Journal articleIEEE Communications Surveys and Tutorials · January 1, 2026
Virtualized networks are built on the principle of replacing bulky and rather static hardware-based functions with software-based, virtualized instances of those functions, enabling more agile and cost-effective communication infrastructures. However, this ...
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Journal articleIEEE Transactions on Sustainable Computing · January 1, 2025
Container technology, as the key enabler behind microservice architectures, is widely applied in Cloud and Edge Computing. A long and continuous running of operating system (OS) hosting container-based services can encounter software aging that leads to pe ...
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Journal articleJournal of Systems and Software · August 1, 2024
In recent years, software bug prediction has shown to be effective in narrowing down the potential bug modules and boosting the efficiency and precision of existing testing and analysis tools. However, due to its non-deterministic nature and low presence, ...
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Journal articleComputer · April 1, 2024
This article discusses model-driven methods with analytic-numeric solutions. In addition to traditional non-state-space and state-space methods, multilevel methods are explored using real case studies. Challenges met while developing and solving dependabil ...
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Journal articleIEEE Transactions on Reliability · March 1, 2024
Traditional software fault tolerance makes use of design-diversity-based redundancy. While proven to be effective, the independent development of multiple versions of a program or component is connected with high costs. This article shows that failures cau ...
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Journal articleIEEE Transactions on Cloud Computing · October 1, 2023
This paper aims to use analytical modeling technique to quantitatively study the dependability of Vehicle Platooning Application, which consists of Multiple Sub-Services (VPP-MSS) to achieve its functionality. Each sub-service (SS), based on network functi ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · July 1, 2023
The Multi-access Edge Computing (MEC) and Network Function Virtualization (NFV) integrated architecture is a key enabling platform for 5G to run multiple customized services in the form of service function chain (SFC) configured as an ordered set of servic ...
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Journal articleIEEE Transactions on Services Computing · July 1, 2023
Multi-access edge computing (MEC)-enabled Internet of Things (IoT) is considered as a promising paradigm to deliver computation-intensive and delay-sensitive services to users. IoT service requests can be served by multiple microservices (MSs) that form a ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · July 1, 2023
As software plays an increasingly important role in our lives, it is essential to maintain its reliability, and generally dependability. Software bugs can cause huge financial losses and dangerous accidents; the safety risks from software are underscored t ...
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Journal articleIEEE Transactions on Vehicular Technology · April 1, 2023
Unmanned aerial vehicle (UAV) and network function virtualization (NFV) facilitate the deployment of multi-access edge computing (MEC). In the UAV-based MEC (UMEC) network, virtualized network function (VNF) can be implemented as a lightweight container ru ...
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Journal articleIEEE Transactions on Reliability · December 1, 2022
Understanding and predicting types of bugs are of practical importance for developers to improve the testing efficiency and take appropriate steps to address bugs in software releases. However, due to the complex conditions under which faults manifest and ...
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Journal articlePeer to Peer Networking and Applications · July 1, 2022
Network function virtualization (NFV) has been explored to be integrated with multi-access edge computing (MEC) to facilitate the development of 5G (fifth-generation) network. Latency-sensitive applications can be deployed as serial-parallel hybrid service ...
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Journal articleComputer · May 1, 2022
Software can show symptoms of two different types of aging. Sometimes, it is even subject to both types. ...
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Journal articleIEEE Transactions on Services Computing · January 1, 2022
Migration-based Dynamic Platform (MDP) technique, a type of Moving Target Defense (MTD) techniques, defends against sophisticated cyber-attacks by randomly and dynamically selecting a platform for executing service/job. Security defense mechanisms protect ...
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Journal articleIEEE Transactions on Cloud Computing · January 1, 2022
With the rapid and wide development and deployment of system virtualization, service availability analysis has become increasingly important in a virtualized system (VS) which suffers from software aging. Software rejuvenation techniques can be applied to ...
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Journal articleIEEE Transactions on Reliability · September 1, 2021
Mandelbug-caused software failures are significant threats to system availability, especially in the context of mission-critical and safety-critical systems. However, there is still no systematic method for keeping the software free from Mandelbugs before ...
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Journal articleIEEE Transactions on Network and Service Management · September 1, 2021
The safety-critical applications of vehicular ad hoc networks (VANETs) require high reliability and low transmission latency. IEEE 802.11p and IEEE 802.11bd are two standards proposed for such vehicular communication systems. In this paper, we propose an e ...
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Journal articleIEEE Transactions on Vehicular Technology · June 1, 2021
Vehicle platooning can be applied to cooperative downloading and uploading (CDU) services through the cooperation between lead vehicle and non-lead vehicles. CDU service can be completed cooperatively by containers constructed in vehicles of the vehicle pl ...
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Journal articleIEEE Transactions on Network and Service Management · June 1, 2021
The recent trend of network softwarization suggests a radical shift in the implementation of traditional network intelligence. In Software Defined Networking (SDN), for instance, the control plane functions of forwarding devices are outsourced to the contr ...
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Journal articleIEEE Transactions on Reliability · June 1, 2021
Intrusion tolerance is an ability to keep the correct service by masking the intrusion based on fault-tolerant techniques. With the rapid development of virtualization, the virtual machine (VM)-based intrusion tolerance scheme has been developed according ...
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Journal articleIEEE Transactions on Network Science and Engineering · January 1, 2021
As multi-hop wireless networks are attracting more attention, the need to evaluate their performance becomes essential. In order to evaluate the performance metrics of multi-hop wireless networks, including sending and receiving rates of a node as well as ...
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Journal articleIEEE Transactions on Network and Service Management · June 1, 2020
In Software Defined Networking (SDN), network programmability is enabled through a logically centralized control plane. Production networks deploy multiple controllers for scalability and reliability reasons, which in turn rely on distributed consensus pro ...
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Journal articleIEEE Transactions on Reliability · March 1, 2020
Software failures caused by data race bugs have always been major concerns in parallel and distributed systems, despite significant efforts spent in software testing. Due to their nondeterministic and hard-to-reproduce features, when evaluating systems' op ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · January 1, 2020
The Internet world is moving toward a scenario where users and applications have very diverse service expectation, making the current best-effort model inadequate and limiting. To be able to design high-availability service systems, it is essential to cons ...
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Journal articleFuture Generation Computer Systems · January 1, 2020
The extent of epistemic uncertainty in modeling and analysis of complex systems is ever growing, mainly due to increasing levels of the openness, heterogeneity and versatility in cloud-based applications that are being adopted in critical sectors, like ban ...
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Journal articleIEEE Access · January 1, 2020
Virtualization technology has promoted the fast development and deployment of cloud computing, and is now becoming an enabler of Internet of Everything. Virtual machine monitor (VMM), playing a critical role in a virtualized system, is software and hence i ...
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Journal articleIEEE Transactions on Reliability · December 1, 2019
This paper presents an empirical study of 5741 bug reports for the Linux kernel from an evolutionary perspective, with the aim of obtaining a deep understanding of bug characteristics in the Linux operating system. Bug classification is performed based on ...
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Journal articleIEEE Transactions on Cloud Computing · October 1, 2019
Infrastructure as a Service (IaaS) is one of the most significant and fastest growing fields in cloud computing. To efficiently use the resources of an IaaS cloud, several important factors such as performance, availability, and power consumption need to b ...
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Journal articleIEEE Transactions on Reliability · September 1, 2019
In long running systems, software tends to encounter performance degradation and increasing failure rate during execution. This phenomenon has been named software aging, which is caused by aging-related bugs (ARBs). Testing resource allocation can be optim ...
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Journal articleIEEE Transactions on Reliability · June 1, 2019
The Android operating system (OS) is a sophisticated man-made system and is the dominant OS in the current smartphone market. Due to the accumulation of errors in the system internal state and the incremental consumption of resources, such as the Dalvik he ...
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Journal articleIEEE Transactions on Network and Service Management · June 1, 2019
In some applicable scenarios, such as community patrolling, mobile nodes are restricted to move only in their own communities. Exploiting the meetings of the nodes within the same community and the nodes within the neighboring communities, a delay tolerant ...
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Journal articleReliability Engineering and System Safety · March 1, 2019
Malicious lateral movement-based attacks have become a potential risk for many systems, bringing highly likely threats to critical infrastructures and national security. When launching this kind of attacks, adversaries first compromise a fraction of the ta ...
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Journal articleReliability Engineering and System Safety · December 1, 2018
Software aging often affects the performance of software systems and may eventually cause them to fail. A complementary approach to handle transient software failures due to the software aging is called software rejuvenation. It is a preventive and proacti ...
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Journal articlePerformance Evaluation · October 1, 2018
Due to the increasing need for computational power, the market has shifted towards big centralized data centers. Understanding the nature of the dynamics of these data centers from machine and job/task perspective is critical to design efficient data cente ...
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Journal articleComputer Journal · October 1, 2018
In this paper, the performance of a grid resource is modeled and evaluated using stochastic reward nets (SRNs), wherein the failure–repair behavior of its processors is taken into account. The proposed SRN is used to compute the blocking probability and se ...
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Journal articleIEEE Transactions on Cloud Computing · October 1, 2018
Heterogeneity prevails not only among physical machines but also among workloads in real IaaS Cloud data centers (CDCs). The heterogeneity makes performance modeling of large and complex IaaS CDCs even more challenging. This paper considers the scenario wh ...
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Journal articleIEEE Transactions on Network and Service Management · September 1, 2018
In software defined networking (SDN), critical control plane functions are offloaded to a software entity known as the SDN controller. Today's SDN controllers are complex software systems, owing to heterogeneity of networks and forwarding devices they supp ...
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Journal articleAnnual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference · July 2018
Outpatient centers comprised of many concurrent clinics increasingly see higher patient volumes. In these centers, decisions to improve clinic flow must account for the high degree of interdependence when critical personnel or equipment is shared between c ...
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Journal articleFuture Generation Computer Systems · June 1, 2018
The increasing shift of various critical services towards Infrastructure-as-a-Service (IaaS) cloud data centers (CDCs) creates a need for analyzing CDCs’ availability, which is affected by various factors including repair policy and system parameters. This ...
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Journal articleElectronic Notes in Theoretical Computer Science · May 9, 2018
Data-centers have recently experienced a fast growth in energy demand, mainly due to cloud computing, a paradigm that lets the users access shared computing resources (e.g., servers, storage, etc.). Several techniques have been proposed in order to allevia ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · January 1, 2018
This paper presents a performability model for RAID storage systems using Markov regenerative process to compare different RAID architectures. While homogeneous Markov models are extensively used for reliability analysis of RAID storage systems, the memory ...
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Journal articleInformation Sciences · January 1, 2018
Transient performance analysis of power distribution network (PDN) after a failure occurrence could facilitate the better design of smart grid. Researchers have proposed analytical models and the numerical solutions to analyze the PDN's transient behaviors ...
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Journal articleJournal of Grid Computing · March 1, 2017
Cloud computing infrastructures are designed to be accessible anywhere and anytime. This requires various fault tolerance mechanisms for coping with software and hardware failures. Hierarchical modeling approaches are often used to evaluate the availabilit ...
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Journal articleIEEE Transactions on Vehicular Technology · March 1, 2017
In a traffic jam or dense vehicle environment, vehicular ad hoc networks (VANETs) cannot meet the safety requirement due to serious packet collisions. The traditional cellular network solves packet collisions but suffers from long end-to-end delay. Third-G ...
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Journal articleIEEE Transactions on Reliability · December 1, 2016
Software rejuvenation is a proactive software control technique that is used to improve a computing system performance when it suffers from software aging. In this paper, a two-granularity inspection-based software rejuvenation policy, which works as a clo ...
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Journal articleReliability Engineering and System Safety · November 1, 2016
The reliability of power grids has been subject of study for the past few decades. Traditionally, detailed models are used to assess how the system behaves after failures. Such models, based on power flow analysis and detailed simulations, yield accurate c ...
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Journal articleReliability Engineering and System Safety · September 1, 2016
Vehicular ad hoc network (VANET) is a technology that facilitates communication between vehicles by creating a 'mobile Internet'. The system aims at ensuring road safety and achieving secured commutation. For this reason, reliability and survivability of t ...
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Journal articleIEEE Transactions on Reliability · March 1, 2016
Software failures are still a major concern in mission- and enterprise-critical contexts, despite significant efforts spent in software testing. In fact, while software testing is effective against easily-reproducible bugs (Bohrbugs), it is considerably le ...
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Journal articleTelecommunication Systems · December 1, 2015
Featured Publication
Survivability is a concept that describes the capability of a system to achieve timely recovery after the occurrence of undesired events. It is more general and detailed than many terms, such as RTO and RPO, that have a similar goal. Survivability is capab ...
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Journal articleTelecommunication Systems · March 27, 2015
Featured Publication
In this position paper on reliable networks, we discuss new trends in the design of reliable communication systems. We focus on a wide range of research directions including protection against software failures as well as failures of communication systems ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · March 1, 2015
In this paper, performance of grid computing environment is studied in the presence of failure-repair of the resources. To achieve this, in the first step, each of the grid resource is individually modeled using Stochastic Reward Nets (SRNs), and mean resp ...
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Journal articleIEEE Transactions on Services Computing · January 1, 2015
Traditional system-oriented dependability metrics like reliability and availability do not fully reflect the impact of system failure-repair behavior in service-oriented environments. The telecommunication systems community prefers to use Defects Per Milli ...
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Journal articleProceedings IEEE 25th International Symposium on Software Reliability Engineering Workshops Issrew 2014 · December 12, 2014
With its simple principles to achieve parallelism and fault tolerance, the Map-reduce framework has captured wide attention, from traditional high performance computing to marketing organizations. The most popular open source implementation of this framewo ...
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Journal articleIEEE Transactions on Computers · December 1, 2014
IEEE 1609.4 protocol defines a channel switching mechanism to enable a single radio operating efficiently on multiple channels to support both safety and non-safety services. Basic safety message (BSM) is transmitted only through the control channel at reg ...
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Journal articleEuropean Journal of Operational Research · November 1, 2014
In this paper, an algorithm for the fast computation of network reliability bounds is proposed. The evaluation of the network reliability is an intractable problem for very large networks, and hence approximate solutions based on reliability bounds have as ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · September 18, 2014
The explosive growth of data generation and increasing reliance of business analysis on massive data make data loss more damaging than ever before. Nowadays many organizations start relying on cloud services for keeping their valuable data. It is a critica ...
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Journal articleInternational Journal of Modern Physics B · September 10, 2014
The paper regards the complex dynamical network (CDN) as a static network with temporal characteristics so as to consider its dynamic behavior. The influence factor and dynamics laws in CDN are explored by using the methods of simulation and statistical ph ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · January 1, 2014
In modern IT systems, data backup and restore operations are essential for providing protection against data loss from both natural and man-made incidents. On the other hand, data backup and restore operations can be resource-intensive and lead to performa ...
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Journal articleIEEE Transactions on Services Computing · January 1, 2014
From an enterprise perspective, one key motivation to transform the traditional IT management into Cloud is the cost reduction of the hosted services. In an Infrastructure-as-a-Service (IaaS) Cloud, virtual machine (VM) instances share the physical machine ...
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Journal articleIEEE Transactions on Cloud Computing · January 1, 2014
In a large Infrastructure-as-a-Service (IaaS) cloud, component failures are quite common. Such failures may lead to occasional system downtime and eventual violation of Service Level Agreements (SLAs) on the cloud service availability. The availability ana ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · January 1, 2014
Software systems running continuously for a long time often confront software aging, which is the phenomenon of progressive degradation of execution environment caused by latent software faults. Removal of such faults in software development process is a c ...
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Journal articleEurasip Journal on Wireless Communications and Networking · December 1, 2012
In the current worldwide ICT scenario, a constantly growing number of ever more powerful devices (smartphones, sensors, household appliances, RFID devices, etc.) join the Internet, significantly impacting the global traffic volume (data sharing, voice, mul ...
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Journal articleACM SIGMETRICS Performance Evaluation Review · March 9, 2012
Reliability and performance evaluation are important, often mandatory, steps in designing and analyzing (critical) systems. In such cases, accurate models are required to adequately take into account interference or dependent behaviors affecting th ...
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Journal articleIEEE Vehicular Technology Conference · December 23, 2011
IEEE- and ASTM-adopted Dedicated Short Range Communications (DSRC) vehicle safety-related communication services, which require reliable and fast message delivery, usually demand broadcast communications in vehicular ad hoc networks (VANETs). In this paper ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · December 14, 2011
High-availability assurance of cloud service is a critical and challenging issue for cloud service providers. To quantify the availability of cloud services from both architectural and operational points of views, availability modeling and evaluation are e ...
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Journal articleCtrq 2011 4th International Conference on Communication Theory Reliability and Quality of Service · December 1, 2011
In this paper, an analytic model is proposed for the performance evaluation of vehicular safety related services in the dedicated short range communications (DSRC) system on highways. The generation and service of safety messages in each vehicle is modeled ...
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Journal articleCtrq 2011 4th International Conference on Communication Theory Reliability and Quality of Service · December 1, 2011
In this paper, we investigate the availability modeling of computer networks with redundancy mechanisms. Sensitivity analysis is applied in order to find the bottlenecks of system availability. We use Markov chains for the analytical evaluation of complex ...
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Journal articleProceedings 2011 3rd International Workshop on Software Aging and Rejuvenation Wosar 2011 · December 1, 2011
A number of studies have reported the phenomenon of "software aging", characterized by progressive software performance degradation. Response time (RT) as a customer-affecting metric can be used to detect the onset of software aging. Alberto Avritzer et al ...
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Journal articleProceedings of IEEE Pacific Rim International Symposium on Dependable Computing Prdc · December 1, 2011
Several studies have been carried out on software bugs analysis and classification for life and mission critical systems, which include reproducible bugs called Bohrbugs, and hard to reproduce bugs called Mandelbugs. Although software reliability in IT sys ...
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Journal articleProceedings 2011 3rd International Workshop on Software Aging and Rejuvenation Wosar 2011 · December 1, 2011
The need for reliability and availability has increased in modern applications, in order to handle rapidly growing demands while providing uninterrupted service. Cloud computing systems fundamentally provide access to large pools of data and computational ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2011
A number of studies have reported the phenomenon of "Software aging", caused by resource exhaustion and characterized by progressive software performance degradation. We develop experiments that simulate an on-line bookstore application, following the stan ...
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Journal articleProceedings 2011 3rd International Workshop on Software Aging and Rejuvenation Wosar 2011 · December 1, 2011
In this paper we present an experimental comparative study of most of the rejuvenation techniques developed so far, divided into two groups: i) simple approaches: physical node reboot (switch off/on), VM reboot, OS reboot and standalone application restart ...
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Journal articleProceedings 2011 3rd International Workshop on Software Aging and Rejuvenation Wosar 2011 · December 1, 2011
In this paper, a multi-granularity software rejuvenation policy isstudied. Four granularities of rejuvenation are proposed tomitigate the impact of four levels of software aging respectively.Continuous Time Markov Chain (CTMC) model is used to obtain theav ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2011
Stochastic models are often employed to study dependability of critical systems and assess various hardware and software fault-tolerance techniques. These models take into account the randomness in the events of interest (aleatory uncertainty) and are gene ...
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Journal articleProceedings 2011 3rd International Workshop on Software Aging and Rejuvenation Wosar 2011 · December 1, 2011
Virtual machine monitor (VMM) rejuvenation is a proactive recovery method against failures caused by software aging in VMM. Since the job running on a hosted virtual machine (VM) is interrupted at VMM rejuvenation, the preemption type of VMM rejuvenation i ...
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Journal articlePerformance Evaluation · October 1, 2011
This paper proposes an improved computation method of maximum likelihood (ML) estimation for phase-type (PH) distributions with a number of phases. We focus on the EM (expectation-maximization) algorithm proposed by Asmussen et al. [27] and refine it in te ...
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Journal articleProceedings of the 12th IFIP IEEE International Symposium on Integrated Network Management IM 2011 · September 19, 2011
As online service providers utilize cloud computing to host their services, they are challenged by evaluating the quality of experience and designing redirection strategies in this complicated environment. We propose a hierarchical modeling approach that c ...
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Journal article2011 Prognostics and System Health Management Conference Phm Shenzhen 2011 · August 3, 2011
A review is carried out on how quantitative approaches have been applied so far to the Reliability Prediction and Assessment (RPA) for computer and communication systems. A series of the reliability evaluation technology based on analytic models and comput ...
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Journal articleComputer Communications · August 2, 2011
IEEE 802.15.4 is a popular choice for MAC/PHY protocols in low power and low data rate wireless sensor networks. In this paper, we develop a stochastic model for the beaconless operation of IEEE 802.15.4 MAC protocol. Given the number of nodes competing fo ...
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Journal articleProceedings of International Conference on Software Engineering Software Quality the Road Ahead Conseg 2011 · January 1, 2011
In this paper, we describe a Markov chain based approach for the performance and availability analysis of cloud provided services. We use infrastructure-asa-service as an example of a cloud based service, where service availability and provisioning respons ...
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Journal articleInternational Journal of Performability Engineering · January 1, 2011
Reliability is one of the key attributes of dependability and quality of service. Techniques and tools for reliability assessment are therefore required in order to evaluate and to predict system behavior. In many contexts, merely taking into account of st ...
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Journal articleInternational Journal of Performability Engineering · January 1, 2011
Survivability is the capability of a system to fulfill its mission in a timely manner in the presence of failures, attacks and accidents. In this paper, quantitative assessment of survivability of cellular networks is conducted by developing an analytical ...
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Journal articleProceedings of the 2011 6th International Conference on Availability Reliability and Security Ares 2011 · January 1, 2011
High-availability assurance of server systems is becoming an important issue, since many mission-critical applications are implemented on server systems. To achieve high-availability, software rejuvenation is a practical technique to reduce unexpected down ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2011
Optimizing for performance is often associated with higher costs in terms of capacity, faster infrastructure, and power costs. In this paper, we quantify the power-performance trade-offs by developing a scalable analytic model for joint analysis of perform ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2011
Over the last decade, research on dependable computing has undergone a shift from reactive towards proactive methods: In classical fault tolerance a system reacts to errors or component failures in order to prevent them from turning into system failures, a ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2011
Over the last decade, research on dependable computing has undergone a shift from reactive towards proactive methods: In classical fault tolerance a system reacts to errors or component failures in order to prevent them from turning into system failures, a ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2011
High availability is one of the key characteristics of Infrastructure-as-a- Service (IaaS) cloud. In this paper, we show a scalable method for availability analysis of large scale IaaS cloud using analytic models. To reduce the complexity of analysis and t ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · December 30, 2010
In this paper, we discuss a Monte Carlo sampling based method for propagating the epistemic uncertainty in model parameters, through the system availability model. We also outline methods to compute the number of samples needed to obtain a desired confiden ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · December 30, 2010
Cloud based services may experience changes - internal, external, large, small - at any time. Predicting and quantifying the effects on the quality-of-service during and after a change are important in the resiliency assessment of a cloud based service. In ...
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Journal articleLecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics · December 15, 2010
Restarts or retries are typical control schemes to meet a deadline in real-time systems, and are regarded as significant environmental diversity techniques in dependable computing. This paper reconsiders a restart control studied by van Moorsel and Wolter ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2010
Defects per million (DPM), defined as the number of calls out of a million dropped due to failures, is an important service (un)reliability measure for telecommunication systems. Most previous research derives the DPM from steady-state system availability ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2010
Software aging is a phenomenon defined as the continuing degradation of software systems during runtime, being particularly noticeable in long-running applications. Aging-related failures are very difficult to observe, because the accumulation of aging eff ...
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Journal articleProceedings 16th IEEE Pacific Rim International Symposium on Dependable Computing Prdc 2010 · December 1, 2010
Prior to field deployment, mission critical sensor networks should be analyzed for high reliability assurance. Past research only focused on reliability models for sensor node or network in isolation. This paper presents a comprehensive approach for reliab ...
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Journal articleProceedings 16th IEEE Pacific Rim International Symposium on Dependable Computing Prdc 2010 · December 1, 2010
Handling diverse client demands and managing unexpected failures without degrading performance are two key promises of a cloud delivered service. However, evaluation of a cloud service quality becomes difficult as the scale and complexity of a cloud system ...
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Journal articleACM International Conference Proceeding Series · November 22, 2010
Attack tree (AT) is one of the widely used combinatorial models in cyber security analysis. The basic formalism of AT does not take into account defense mechanisms. Defense trees (DT) have been developed to investigate the effect of defense mechanisms usin ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · September 20, 2010
As space mission software becomes more complex, the ability to effectively deal with faults is increasingly important. The strategies that can be employed for fighting a software bug depend on its fault type. Bohrbugs are easily isolated and removed during ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · September 20, 2010
Proactive approaches to failure avoidance, recovery and maintenance have recently attracted increased interest among researchers and practitioners from various areas of dependable system design and operation. This first workshop provided a stimulating, and ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · September 20, 2010
Proactive approaches to failure avoidance, recovery and maintenance have recently attracted increased interest among researchers and practitioners from various areas of dependable system design and operation. This first workshop provided a stimulating, and ...
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Journal articleEdcc 8 Proceedings of the 8th European Dependable Computing Conference · July 12, 2010
Reliability is one of the major concerns for software engineers. The increasing size of software systems and their inherent complexity - which is essentially related to the intricate interdependencies among many heterogeneous components - pose serious diff ...
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Journal articleIEEE Transactions on Software Engineering · March 29, 2010
With software systems increasingly being employed in critical contexts, assuring high reliability levels for large, complex systems can incur huge verification costs. Existing standards usually assign predefined risk levels to components in the design phas ...
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Journal articleInternational Journal of System Assurance Engineering and Management · January 1, 2010
Companies are expected to keep their systems up and running and make data continuously available. Several recent studies have established that most system outages are due to software faults. In this paper, we discuss availability aspects of large software- ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · January 1, 2010
A number of studies have reported the phenomenon of "Software aging", characterized by progressive software performance degradation. This is mainly caused by the exhaustion of the combination of system resources. Traditionally, modeling and analysis of sof ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · January 1, 2010
As server virtualization is used as an essential software infrastructure of various software services such as cloud computing, availability management of server virtualized system is becoming more significant. Although time-based software rejuvenation is u ...
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Journal articleIEEE Transactions on Computers · January 1, 2010
A distinct characteristic of multistate systems (MSS) is that the systems and/or their components may exhibit multiple performance levels (or states) varying from perfect operation to complete failure. MSS can model behaviors such as shared loads, performa ...
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Journal articleIEEE Transactions on Reliability · January 1, 2010
In the past ten years, the software aging phenomenon has been systematically researched, and recognized by both academic, and industry communities as an important obstacle to achieving dependable software systems. One of its main effects is the depletion o ...
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Journal articleProceedings of the 2009 7th International Workshop on the Design of Reliable Communication Networks Drcn 2009 · December 16, 2009
There is a need to quantify system properties methodically. Dependability and security models have evolved nearly independently. Therefore, it is crucial to develop a classification of dependability and security models which can meet the requirement of pro ...
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Journal article2008 IEEE International Conference on Software Reliability Engineering Workshops ISSRE Wksp 2008 · December 15, 2009
Virtualization enables data centers to consolidate servers to improve resource utilization and power consumption. This paper presents the issues of performability management in a virtualized data center that hosts multiple services using virtualization. On ...
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Journal article2008 IEEE International Conference on Software Reliability Engineering Workshops ISSRE Wksp 2008 · December 15, 2009
Since the notion of software aging was introduced thirteen years ago, the interest in this phenomenon has been increasing from both academia and industry. The majority of the research efforts in studying software aging have focused on understanding its eff ...
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Journal article2009 15th IEEE Pacific Rim International Symposium on Dependable Computing Prdc 2009 · December 1, 2009
This paper develops an availability model of a virtualized system. We construct non-virtualized and virtualized two hosts system models using a two-level hierarchical approach in which fault trees are used in the upper level and homogeneous continuous time ...
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Journal articleInternational Symposium on Performance Evaluation of Computer and Telecommunication Systems 2009 Spects 2009 Part of the 2009 Summer Simulation Multiconference Summersim 2009 · December 1, 2009
IEEE 802.15.4 is a popular choice for MAC/PHY protocols in low power and low data rate wireless sensor networks. In this paper, we develop a stochastic model for the beaconless operation of IEEE 802.15.4 MAC protocol. Given the number of nodes competing fo ...
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Journal articleProceedings Winter Simulation Conference · December 1, 2009
Critical services in a telecommunication network should survive and be continuously provided even when undesirable events like sabotage, natural disasters, or network failures happen. The network survivability is quantified as defined by the ANSI T1A1.2 co ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · November 25, 2009
Proactive approaches to failure avoidance, recovery and maintenance have recently attracted increased interest among researchers and practitioners from various areas of dependable system design and operation. This first workshop aimed to provide a stimulat ...
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Journal articleProceedings of the 2009 International Symposium on Performance Evaluation of Computer and Telecommunication Systems Spects 2009 · November 12, 2009
IEEE 802.15.4 is a popular choice for MAC/PHY protocols in low power and low data rate wireless sensor networks. In this paper, we develop a stochastic model for the beaconless operation of IEEE 802.15.4 MAC protocol. Given the number of nodes competing fo ...
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Journal articleProceedings International Conference on Advanced Information Networking and Applications AINA · October 5, 2009
OSPF is a popular interior gateway routing protocol. Commercial OSPF routers limit their processing load by using a hold time between successive routing table calculations as new link state advertisements (LSAs) arrive following a topology change. A large ...
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Journal articleInternational Journal of Reliability Quality and Safety Engineering · August 1, 2009
Service Reliability is an important consideration for new service deployment. Traditional system-oriented measures are no longer adequate to describe the reliability perceived by the user. In this paper we propose a general service reliability analysis app ...
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Journal articleIEEE ACM Transactions on Networking · July 3, 2009
This paper addresses a parameter estimation problem of Markovian arrival process (MAP). In network traffic measurement experiments, one often encounters the group data where arrival times for a group are collected as one bin. Although the group data are ob ...
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Journal articleComputer Networks · June 11, 2009
Critical services in a telecommunication network should be continuously provided even when undesirable events like sabotage, natural disasters, or network failures happen. It is essential to provide virtual connections between peering nodes with certain pe ...
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Journal articleACM SIGMETRICS Performance Evaluation Review · March 25, 2009
This paper discusses the modeling tool called SHARPE (Symbolic Hierarchical Automated Reliability and Performance Evaluator), a general hierarchical modeling tool that analyzes stochastic models of reliability, availability, performance, and perfor ...
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Journal articleIEEE ACM International Conference on Computer Aided Design Digest of Technical Papers Iccad · January 1, 2009
The term resilience is used differently by different communities. In general engineering systems, fast recovery from a degraded system state is often termed as resilience. Computer networking community defines it as the combination of trustworthiness (depe ...
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Journal articleProceedings of the 14th IEEE Pacific Rim International Symposium on Dependable Computing Prdc 2008 · December 1, 2008
We present the availability model of a high availability SIP Application Server configuration on WebSphere. Hardware, operating system and application server failures are considered. Different types of fault detectors, detection delays, failover delays, re ...
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Journal articleIBM Systems Journal · December 1, 2008
The successful development and marketing of commercial high-availability systems requires the ability to evaluate the availability of systems. Specifically, one should be able to demonstrate that projected customer requirements are met, to identify availab ...
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Journal articleProc the 3rd Int Conf Systems and Networks Communications Icsnc 2008 Includes I Centric 2008 Int Conf Advances in Human Oriented and Personalized Mechanisms Technologies and Services · December 1, 2008
In a telecommunication network it is essential to provide virtual connections between peering nodes with performance guarantees such as minimum throughput, maximum delay or loss. Critical services in telecommunication network should be continuously provide ...
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Journal articleIPDPS Miami 2008 Proceedings of the 22nd IEEE International Parallel and Distributed Processing Symposium Program and Cd Rom · September 10, 2008
We discuss availability aspects of large software-based systems. We classify faults into Bohrbugs, Mandelbugs and aging-related bugs, then examine mitigation methods for the last two bug types. We also consider quantitative approaches to availability assur ...
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Journal articleLecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics · June 11, 2008
We discuss availability aspects of large software-based systems. We classify faults into Bohrbugs, Mandelbugs and aging-related bugs, and then examine mitigation methods for the last two bug types. We also consider quantitative approaches to availability a ...
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Journal articleLecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics · June 9, 2008
As modern society becomes more and more dependent on computers and computer networks, vulnerability and downtime of these systems will significantly impact daily life from both social and economic point of view. Words like reliability and downtime are freq ...
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Journal articleElectronic Transactions on Numerical Analysis · January 1, 2008
This contribution proposes a decompositional iterative method with low memory requirements for the steadystate analysis ofKronecker structured Markov chains. The Markovian system is formed by a composition of subsystems using the Kronecker sum operator for ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2008
Our society is heavily dependent on a wide variety of communication services. These services must be available even when undesirable events like sabotage, natural disasters, or network failures happen. The network survivability as defined by the ANSI T1A1. ...
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Journal articleIEEE Transactions on Vehicular Technology · January 1, 2008
For cellular communication systems, mobility and limited radio coverage of a cell require calls to be handed over from one base station system (BSS) to another. Due to the limited bandwidth available in various cells, there is a finite probability that an ...
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Journal articleIEEE Transactions on Reliability · December 1, 2007
Recently, measurement-based studies of software systems have proliferated, reflecting an increasingly empirical focus on system availability, reliability, aging, and fault tolerance. However, it is a nontrivial, error-prone, arduous, and time-consuming tas ...
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Journal articleProceedings of IEEE International Symposium on High Assurance Systems Engineering · December 1, 2007
Computer and communication systems are ubiquitous and are used extensively in safety critical, life critical, and finance critical applications. Due to the excessive cost of outages, downtime is not tolerated by the users. High availability applications ar ...
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Journal articleIEEE Transactions on Reliability · September 1, 2007
This paper proposes a hierarchical modeling approach for the reliability analysis of phased-mission systems with repairable components. The components at the lower level are described by continuous time Markov chains which allow complex component failure/r ...
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Journal articleIEEE Transactions on Computers · July 1, 2007
Grid computing is a newly emerging technology aimed at large-scale resource sharing and global-area collaboration. It is the next step in the evolution of parallel and distributed computing. Due to the largeness and complexity of the grid system, its perfo ...
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Journal articleJournal of Systems and Software · April 1, 2007
With component-based systems becoming popular and handling diverse and critical applications, the need for their thorough evaluation has become very important. In this paper we propose an architecture-based unified hierarchical model for software performan ...
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Journal articlePerformance Evaluation · March 1, 2007
This paper develops time-based rejuvenation policies to improve the performability measures of a cluster system. Three rejuvenation policies, namely standard rejuvenation, delayed rejuvenation and mixed rejuvenation, are designed to improve the cluster's p ...
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Journal articleLecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics · January 1, 2007
Web services providers often commit service-level agreements (SLAs) with their customers for guaranteeing the quality of the services. These SLAs are related not just to functional attributes of the services but to performance and reliability attributes as ...
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Journal articleProceedings 2007 IEEE International Conference on Services Computing Scc 2007 · January 1, 2007
Stochastic reliability analysis of composite services is challenging, primarily since it needs us to carefully balance accuracy of analysis and its computational complexity: Given stochastic models of service components, we often combine them and define a ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2007
In this paper, we present a variational Bayesian (VB) approach to computing the interval estimates for nonhomogeneous Poisson process (NHPP) software reliability models. This approach is an approximate method that can produce analytically tractable posteri ...
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Journal articleIEEE Transactions on Reliability · December 1, 2006
Traditional approaches to software reliability modeling are black box-based; that is, the software system is considered as a whole, and only its interactions with the outside world are modeled without looking into its internal structure. The black box appr ...
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Journal articleInternational Symposium on Performance Evaluation of Computer and Telecommunication Systems 2006 Spects 06 Part of the 2006 Summer Simulation Multiconference Summersim 06 · December 1, 2006
Survivability analysis measure the degree of functionality remaining in a system after failures. It consists of evaluating metrics which quantify the system performance during failure scenarios as well as in normal operation. Existing research work in this ...
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Journal articleProceedings 12th Pacific Rim International Symposium on Dependable Computing Prdc 2006 · December 1, 2006
Carrier grade high availability platforms are designed to enable the development and deployment of highly available services in the telecommunications industry. In order to build-in high availability and compare availabilities that differ in the sixth deci ...
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Journal articleProceedings 12th Pacific Rim International Symposium on Dependable Computing Prdc 2006 · December 1, 2006
Recently, measurement based studies of software systems proliferated, reflecting an increasingly empirical focus on system availability, reliability, aging and fault tolerance. However, it is a non-trivial, error-prone, arduous, and time-consuming task eve ...
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Journal articleProceedings International Computer Software and Applications Conference · December 1, 2006
Performance engineering is an important activity for software architects and designers. Assessment and tuning of performance can help to make key changes in the system, especially if done early in its development. In this paper, we present a tool for the p ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2006
High reliability and performance are vital for software systems handling diverse mission critical applications. Such software systems are usually component based and may possess multiple levels of fault recovery. A number of parameters, including the softw ...
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Journal articleIEEE Transactions on Reliability · September 1, 2006
Several recent studies have reported & examined the phenomenon that long-running software systems show an increasing failure rate and/or a progressive degradation of their performance. Causes of this phenomenon, which has been referred to as "software agin ...
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Journal articleIEEE Transactions on Vehicular Technology · September 1, 2006
In this paper, a new soft handoff scheme for CDMA cellular systems is proposed and investigated. It is pointed out that some handoff calls unnecessarily occupy multiple channels with little contribution to the performance of handoffs in IS95/CDMA2000-based ...
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Journal articleIEEE Transactions on Reliability · June 1, 2006
A large number of software reliability growth models have been proposed to analyse the reliability of a software application based on the failure data collected during the testing phase of the application. To ensure analytical tractability, most of these m ...
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Journal articleIEEE Transactions on Vehicular Technology · March 1, 2006
This paper investigates the features of a cellular geometry in code-division multiple-access (CDMA) systems with soft handoff and distinguishes controlling area of a cell from coverage area of a cell. Some important characteristics of the cellular configur ...
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Journal articleInternational Journal of Performability Engineering · January 1, 2006
In this paper, we present a general survivability quantification approach that is applicable to a wide range of system architectures, applications, failure/recovery behaviors, and metrics. We show how this approach can be applied to derive survivability me ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2006
We present three algorithms for detecting the need for software rejuvenation by monitoring the changing values of a customer-affecting performance metric, such as response time. Applying these algorithms can improve the values of this customer-affecting me ...
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Journal articleProceedings International Computer Software and Applications Conference · December 1, 2005
In this paper, we describe three different state space models for analyzing the security of a software system. In the first part of this paper, we utilize a semi-Markov Process (SMP) to model the transitions between the security states of an abstract softw ...
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Journal articleReliability Engineering and System Safety · October 1, 2005
The semi-Markov decision model is a powerful tool in analyzing sequential decision processes with random decision epochs. In this paper, we have built the semi-Markov decision process (SMDP) for the maintenance policy optimization of condition-based preven ...
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Journal articleIEEE Transactions on Reliability · September 1, 2005
We present a hierarchical model for the analysis of proactive fault management in the presence of system resource leaks. At the low level of the model hierarchy is a degradation model in which we use a nonhomogeneous Markov chain to establish an explicit c ...
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Journal articleIEEE Transactions on Reliability · September 1, 2005
Mean time to failure (MTTF) is an important reliability measure. Previous research is mainly concerned with the MTTF computation of coherent systems. In this paper, we derive equations to calculate the steady-state MTTF for noncoherent systems. Based on th ...
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Journal articleReliability Engineering and System Safety · January 1, 2005
A two-level rejuvenation policy for software systems with degradation process is studied. Both full restarts and partial restarts are considered in this rejuvenation strategy. A semi-Markov process model is constructed, and based on its closed-form solutio ...
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Journal articleOpsearch (India) · 2005
All non-homogeneous Poisson process (NHPP) software reliability growth models of the finite failures category share the property that every time to failure distribution is defective. The reason for this phenomenon is the fact that according to these models ...
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Journal articleComputer Communications · 2005
In this paper, we propose a high availability design of a Cable Modem Termination System (CMTS) clusters system based on the software rejuvenation technique. This proactive system maintenance technique is aimed to reduce system outages and the associated d ...
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Journal articleProceedings Winter Simulation Conference · January 1, 2005
Cellular networks are gradually shifting from voice only to voice and data due to increased demand for WWW, FTP and multi-media messaging. This has substantially increased the volume of cellular data traffic. Schemes have been proposed for co-existence and ...
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Journal articleProceedings of the Fifth International Workshop on Software and Performance WOSP 05 · January 1, 2005
With software systems becoming more complex, and handling diverse and critical applications, the need for their thorough evaluation has become ever more important at each phase of software development. With the prevalent use of component-based design, the ...
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Journal articleLecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics · January 1, 2005
Service availability is an important consideration when carriers deploy new, packet-based services. In this paper we define the service availability based on user behavior, and derive formulas to compute service availability starting with the user behavior ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · January 1, 2005
Recently, the phenomenon of software aging, one in which the state of the software system degrades with time, has been reported. This phenomenon, which may eventually lead to system performance degradation and/or crash/hang failure, is the result of exhaus ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2005
Many software reliability growth models assume that the time to next failure may be infinite; i.e., there is a chance that no failure will occur at all. For most software products this is too good to be true even after the testing phase. Moreover, if a non ...
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Journal articleInternational Conference on Information Technology Coding and Computing ITCC · January 1, 2005
Software coding practices, in the interest of efficiency, often ignore to enforce strict bound checking on buffers, arrays and pointers. This results in software code that is more vulnerable to security intrusions exploiting buffer overflow vulnerabilities ...
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Journal articleLecture Notes in Computer Science · January 1, 2005
The architecture of a software system is the highest level of abstraction whereupon useful analysis of system properties is possible. Hence, performance analysis at this level can be useful for assessing whether a proposed architecture can meet the desired ...
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Journal articleJournal of High Speed Networks · December 29, 2004
Increasing deployment of computer systems in critical applications has made study and quantifiable analysis of the security aspects of these systems an important issue. Security quantification analysis can either be done by logging large amounts of operati ...
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Journal articlePerformance Evaluation · December 1, 2004
Conventional approaches to analyze the behavior of software applications are black box based, that is, the software application is treated as a whole and only its interactions with the outside world are modeled. The black box approaches ignore information ...
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Journal articleProceedings International Symposium on Software Reliability Engineering ISSRE · December 1, 2004
The telecommunications industry has achieved high reliability and availability for telephone service over decades of development. However, the current design does not aim at providing service survivability when a local switching office fails due to catastr ...
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Journal articleProceedings Asia Pacific Software Engineering Conference APSEC · December 1, 2004
In general, the software reliability models based on the non-homogeneous Poisson processes (NHPPs) are quite popular to assess quantitatively the software reliability and its related dependability measures. Nevertheless, it is not so easy to select the bes ...
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Journal articleIEEE Transactions on Wireless Communications · September 1, 2004
In this paper, an optimal training equalization for wireless communication is proposed and analyzed. By our scheme, the training of the equalizer is carried out periodically, with the training interval optimized for a maximal channel utilization. A closed- ...
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Journal articleProceedings IEEE Pacific Rim International Symposium on Dependable Computing · June 15, 2004
This paper analyzes two software rejuvenation policies of cluster server systems under varying workload, called fixed rejuvenation and delayed rejuvenation. In order to achieve a higher average throughput, we propose the delayed rejuvenation policy, which ...
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Journal articlePerformance Evaluation · May 1, 2004
Capacity-on-demand is the key concept in multiplexing bursty mobile data traffic over wireless links featuring limited bandwidth. This scheme maintains a connection for a mobile only when it has data to transfer and allows quick release of radio resource w ...
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Journal articlePerformance Evaluation · March 1, 2004
Complex software and network based information server systems may exhibit failures. Quite often, such failures may not be accidental. Instead some failures may be caused by deliberate security intrusions with the intent ranging from simple mischief, theft ...
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Journal articleIEICE Transactions on Information and Systems · January 1, 2004
Software rejuvenation is a preventive and proactive solution that is particularly useful for counteracting the phenomenon of software aging. In this paper, we consider both the periodic and non-periodic software rejuvenation policies under different depend ...
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Journal articleSoftware Quality Journal · January 1, 2004
Software reliability is an important metric that quantifies the quality of a software product and is inversely related to the residual number of faults in the system. Fault removal is a critical process in achieving desired level of quality before software ...
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Journal articleIEEE Transactions on Dependable and Secure Computing · January 1, 2004
The development of techniques for quantitative, model-based evaluation of computer system dependability has a long and rich history. A wide array of model-based evaluation techniques is now available, ranging from combinatorial methods, which are useful fo ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2004
As the new generation high-availability commercial computer systems incorporate deferred repair service strategies, steady-state availability metrics may no longer reflect reality. Transient solution of availability models for such systems to calculate int ...
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Journal articleIEEE Transactions on Computers · December 1, 2003
In this paper, a new algorithm based on Binary Decision Diagram (BDD) for the analysis of a system with multistate components is proposed. Each state of a multistate component is represented by a Boolean variable, and a multistate system is represented by ...
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Journal articleProceedings of the American Control Conference · November 6, 2003
This paper presents software performance analysis using a finite state automaton model. A signed real measure of formal languages has been used for quantitative evaluation of the software. This paper extends an earlier model based on a discrete time Markov ...
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Journal articleIEEE Transactions on Vehicular Technology · November 1, 2003
Performance modeling of the contention-based reservation protocol in general packet radio service (GPRS)/enhanced general packet radio service (EGPRS) under bursty traffic is practically useful in system design. Instead of using discrete event simulation, ...
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Journal articleComputer Communications · September 22, 2003
Handoff is an important issue in cellular mobile telephone systems. Recently, studies that question the validity of the assumption of handoff arrivals being Poissonian have appeared in the literature. The reasoning behind this claim can be summarized as fo ...
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Journal articleInternational Journal of Reliability Quality and Safety Engineering · September 1, 2003
Preventive maintenance is applied to improve the system availability or decrease the operational cost. This paper addresses the optimal preventive maintenance problem for multi-state deteriorating systems, where the system experiences multiple stages of pe ...
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Journal articleInternational Journal of Communication Systems · August 1, 2003
The high expectations of performance and availability for wireless mobile systems has presented great challenges in the modelling and design of fault tolerant wireless systems. The proper modelling methodology to study the degradation of such systems is so ...
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Journal articleIEEE International Conference on Communications · July 18, 2003
We propose to use Markov regenerative process (MRGP) models to study the availability of Internet-based services perceived by a Web user, which capture the interactions between the service facility and the user. The necessity of the sophisticated MRGP mode ...
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Journal articleIEEE Transactions on Reliability · March 1, 2003
Telecommunication systems are large and complex, consisting of multiple intelligent modules in shelves, multiple shelves in frames, and multiple frames to compose a single network element. In the availability and performability analysis of such a complex s ...
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Journal articleProceedings of the IEEE · January 1, 2003
Real-time systems are an important class of process control systems that need to respond to events under time constraints, or deadlines. Such systems may also be required to deliver service in spite of hardware or software faults in their components. This ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2003
We present a framework of adaptive estimation and rejuvenation of software system performance in the presence of aging sources. The framework specifies that a degradation model not only describe an aging process but also enable the adaptation of model-base ...
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Journal articleComputers and Mathematics with Applications · January 1, 2003
With growing emphasis on reuse, the software development process moves toward component-based software design. As a result, there is a need for modeling approaches that are capable of considering the architecture of the software made out of components. Thi ...
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Journal articleProceedings of the ACM Workshop on Survivable and Self Regenerative Systems · January 1, 2003
Security is an important QoS attribute for characterizing intrusion tolerant computing systems. Frequently however, the security of computing systems is assessed in a qualitative manner based on the presence and absence of certain functional characteristic ...
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Journal articleProceedings of the International Conference on Dependable Systems and Networks · January 1, 2003
The presence of physical obstacles and radio interference results in the so called "shadow regions" in wireless networks. When a mobile station roams into a shadow region, it loses its network connectivity. In cellular networks, in order to minimize the co ...
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Journal articleProceedings of the Annual Reliability and Maintainability Symposium · January 1, 2003
An overview is given of novel techniques for computing importance measures in state space dependability models. Specifically, reward functions in a Markov reward model (MRM) are utilized for this purpose, in contrast to the common method of computing impor ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · December 17, 2002
Recently, the phenomenon of "software aging", one in which the state of a software system gradually degrades with time and eventually leads to performance degradation or crash/hang failure, has been reported. Preventive maintenance of operational software ...
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Journal articleInformation Sciences · December 1, 2002
In this paper, we report our recent work on closed form solutions to the blocking and dropping probability in wireless cellular networks with handoff. First, we develop a performance model of a cell in a wireless network where the effect of handoff arrival ...
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Journal articleProceedings of the Joint Conference on Information Sciences · December 1, 2002
In this paper, we report our recent work on closed form solutions to the blocking and dropping probability in wireless cellular networks with handoff. First, we develop a performance model of a cell in a wireless network where the effect of handoff arrival ...
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Journal articleProceedings of the IEEE Conference on Decision and Control · December 1, 2002
This paper addresses the outage problem and its mitigation for quality of service (QoS) of wireless networks with fading channels. At first, we set up a continuous time Markov chain (CTMC) model that includes various source states and channel outage states ...
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Journal articleProceedings of the International Workshop on Modeling Analysis and Simulation of Wireless and Mobile Systems · December 1, 2002
Network survivability reflects the ability of a network to continue to function during and after failures. Our purpose in this paper is to propose a quantitative approach to evaluate network survivability. We perceive the network survivability as a composi ...
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Journal articleProceedings of the 2002 International Conference on Dependable Systems and Networks · December 1, 2002
A tool called Software Reliability Estimation and Prediction Tool (SREPT) that seeks to address the limitation given in other tools is presented. Unlike most models that assume instantaneous and perfect debugging, SREPT allows the users to analyze the effe ...
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Journal articleProceedings of the 2002 International Conference on Dependable Systems and Networks · December 1, 2002
Quite often failures in network based services and server systems may not be accidental, but rather caused by deliberate security intrusions. We would like such systems to either completely preclude the possibility of a security intrusion or design them to ...
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Journal articleIEEE Transactions on Reliability · June 1, 2002
This paper studies the steady-state availability of systems with times to outages and recoveries that are generally distributed. Availability bounds are derived for systems with limited information about the distributions. Also investigated are the applica ...
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Journal articleComputer Communications · May 1, 2002
Call admission control (CAC) algorithms that reduce dropped calls in code-division multiple access (CDMA) cellular systems are discussed in this paper. The capacity of a CDMA system is confined by the interference of users from both inside and outside of t ...
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Journal articlePerformance Evaluation · 2002
In this paper, the analysis of second-order stochastic fluid models, where the fluid rate is dependent on the fluid level, is addressed. The boundary conditions are presented for the fluid models under consideration, which have extended previous work with ...
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Journal articleApplied Numerical Mathematics · January 1, 2002
We propose a methodology aimed at automating the software development of fast discrete transforms for N-body problems. The methodology starts with a representation of the transform matrix in compact form. Then, two translation phases are applied. One trans ...
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Journal articleReliab. Eng. Syst. Saf. (UK) · 2002
Preventive maintenance is applied to improve the device availability or decrease the repair costs when the device failures are in deterioration (or aging) phase. Preventive maintenance can be made more efficient by periodic monitoring wherein the state of ...
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Journal articleProceedings of the 2002 International Conference on Dependable Systems and Networks · January 1, 2002
The NASA Remote Exploration and Experimentation (REE) Project, managed by the Jet Propulsion Laboratory, has the vision of bringing commercial supercomputing technology into space, in a form which meets the demanding environmental requirements, to enable a ...
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Journal articleProceedings of the 2002 International Conference on Dependable Systems and Networks · January 1, 2002
In this paper, we characterize a broad class C of prefetching algorithms and prove that, for any prefetching algorithm in this class, its total elapsed time is no more than twice the smallest possible total elapsed time. This result provides a performance ...
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Journal articleProceedings of the 2002 International Conference on Dependable Systems and Networks · January 1, 2002
SHARPE is a well known package in the field of reliability and performability, used in universities as well as in companies. It is believed that SHARPE is a useful modeler's "toolchest" because it contains support for multiple model types and provides flex ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · January 1, 2002
In this paper, we consider a new stochastic model for a file recovery action with checkpointing when the system failure occurs according to a homogeneous Poisson process. The present checkpoint model strongly depends on the system age and is quite differen ...
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Journal articleIEEE International Conference on Communications · January 1, 2002
In this paper, an optimal training equalization for wireless communication is proposed and analyzed. By our scheme, the training of the equalizer is carried out periodically, with the training interval optimized for a maximal channel utilization. A closed- ...
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Journal articleProceedings of the Annual Reliability and Maintainability Symposium · January 1, 2002
In this paper we develop analytical models for the study of the dependability characteristics of systems with uninterruptible power supply (UPS) units. Dependability of systems with UPS cannot be modeled exactly using the prevalent Markov modeling approach ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 2001
This article gives the detailed mathematical results on the hypergeometric distribution software reliability model (HGDSRM) proposed by Tohma et al. [IEEE Trans. Software Eng. (1989, 1991)]. In the above papers, Tohma et al. developed the HGDSRM as a discr ...
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Journal articleComputer Journal · December 1, 2001
Software rejuvenation is a preventive maintenance technique that has been extensively studied in recent literature. In this paper, we extend the classical result by Huang et al. (1995), and in addition propose a modified stochastic model to generate the so ...
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Journal articleElectronics Letters · November 22, 2001
The problem of transmission control protocol (TCP) traffic with random early detection (RED) is addressed. With the formulation of stochastic differential equation (SDE), an explicit expression for the relation between RED parameters and network parameters ...
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Journal articleComputer Communications · October 1, 2001
In this paper, we develop a concise performance model of partial packet discard (PPD) and early packet discard (EPD) schemes in ATM switches. We study the performance of PPD and EPD with heterogeneous traffic sources. The sources included Poisson, and ON-O ...
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Journal articleIEEE Transactions on Vehicular Technology · September 1, 2001
With the increasing popularity of wireless communication systems, customers are expecting the same level of service, availability, and performance from the wireless communication networks as the traditional wire-line networks. Traditional pure performance ...
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Journal articleComputer Communications · July 15, 2001
A single base repeater failure in time division multiple access (TDMA) wireless systems causes all active calls on this base repeater to be dropped. In order to increase system end-to-end availability, a multiple channel recovery method for TDMA wireless s ...
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Journal articlePerformance Evaluation · July 1, 2001
With the growing emphasis on reuse, software development process moves toward component-based software design. As a result, there is a need for modeling approaches that are capable of considering the architecture of the software and estimating the reliabil ...
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Journal articleIEEE ACM Transactions on Networking · June 1, 2001
In this paper, we develop performance models of the Broadcast and Unknown Server (BUS) in the LANE. The traffic on the BUS is divided into two classes: the broadcast and multicast traffic, and the unicast relay flow. The broadcast and multicast traffic is ...
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Journal articleIEEE Transactions on Vehicular Technology · May 1, 2001
In this paper, we develop a performance model of a cell in a wireless communication network where the effect of handoff arrival and the use of guard channels is included. Fast recursive formulas for the loss probabilities of new calls and handoff calls are ...
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Journal articlePerformance Evaluation Review · January 1, 2001
Several recent studies have reported the phenomenon of "software aging", one in which the state of a software system degrades with time. This may eventually lead to performance degradation of the software or crash/hang failure or both. "Software rejuvenati ...
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Journal articleDiscrete Event Dynamic Systems: Theory and Applications · 2001
Hybrid Systems are models of interacting digital and continuous devices with applications in the control of aircraft, computers, or modern cars for instance. Concurrently, Fluid Stochastic Petri Nets (FSPNs) have been introduced as an extension of stochast ...
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Journal articleIBM Journal of Research and Development · January 1, 2001
In response to the strong desire of customers to be provided with advance notice of unplanned outages, techniques were developed that detect the occurrence of software aging due to resource exhaustion, estimate the time remaining until the exhaustion reach ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · January 1, 2001
Many architecture-based software reliability models have been proposed in the past without any attempt to establish a relationship among them. The aim of this paper is to fill this gap. First, the unifying structural properties of the models are exhibited ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · January 1, 2001
As CORBA (Common Object Request Broker Architecture) gains popularity as a standard for portable, distributed, object-oriented computing, the need for a CORBA messaging solution is being increasingly felt. This led the Object Management Group (OMG) to spec ...
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Journal articleProceedings of the Annual Reliability and Maintainability Symposium · January 1, 2001
In reliability analysis of computer systems, models such as fault trees, Markov chains, and stochastic Petri nets(SPN) are built to evaluate or predict the reliability of the system. In general, the parameters in these models are usually obtained from fiel ...
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Journal articleIEEE Transactions on Reliability · December 1, 2000
Perhaps the most stringent restriction in most software reliability models is the assumption of statistical independence among successive software failures. Our research was motivated by the fact that although there are practical situations in which this a ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 2000
The GMDH (group method of data handling) network is an adaptive learning machine based on the principle of heuristic self-organization. In this paper, we apply the GMDH networks to predict software reliability in testing phase. Three kinds of networks: the ...
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Journal articleConference Record IEEE Global Telecommunications Conference · December 1, 2000
Traditional pure performance model that ignores failure and recovery but considers resource contention generally overestimates the system's ability to perform a certain job. On the other hand, pure availability analysis tends to be too conservative since p ...
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Journal articlePerformance Evaluation · January 1, 2000
Several tools have been developed for the estimation of software reliability. However, they are highly specialized in the approaches they implement and the particular phase of the software life-cycle in which they are applicable. There is an increasing nee ...
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Journal articleEuropean Transactions on Telecommunications · January 1, 2000
With the increasing penetration of wireless communications systems, customers are expecting the same level of service, reliability and performance from the wireless communication systems as the traditional wire-line networks. Due to the dynamic environment ...
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Journal articleProceedings of the IEEE Symposium on Reliable Distributed Systems · January 1, 2000
The Event service is the earliest CORBA solution to the message queue model of communication in distributed systems. Typical implementations however suffer from the lack of event delivery guarantees. The loss of messages is aggravated in the presence of bu ...
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Journal articleProceedings of the IEEE Annual Simulation Symposium · January 1, 2000
Software systems are known to suffer from outages due to transient errors. Recently, the phenomenon of 'software aging', one in which the state of the software system degrades with time, has been reported. To counteract this phenomenon, a proactive approac ...
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Journal articleProceedings IEEE INFOCOM · January 1, 2000
Call admission control algorithms that reduce dropped calls in CDMA cellular systems are discussed in this paper. The capacity of a CDMA system is confined by interference of users from both inside and outside of the target cell. Earlier algorithms for cal ...
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Journal articleIEEE Transactions on Reliability · December 1, 1999
This paper presents a new algorithm (PMS-BDD) based on the binary decision diagram (BDD) for reliability analysis of phased-mission systems (PMS). PMS-BDD uses phase algebra to deal with the dependence across the phases, and a new BDD operation to incorpor ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1999
Software systems are known to suffer from outages due to transient errors. Recently, the phenomenon of `software aging', one in which the state of the software system degrades with time, has been reported. The primary causes of this degradation are the exh ...
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Journal articleIEEE Vehicular Technology Conference · December 1, 1999
A single base repeater failure in TDMA wireless systems causes all active calls on this base repeater to be dropped. In order to increase system end-to-end availability, an RF channel recovery method for TDMA wireless systems is proposed in this paper. By ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1999
Perhaps the most stringent restriction that is present in most software reliability models is the assumption of independence among successive software failures. Our research was motivated by the fact that although there are practical situations in which th ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1999
The software reliability growth models (such as NHPP models) are frequently used in software reliability prediction. Estimation of parameters in these models is often done by point estimation. However, some numerical problems arise and make the actual comp ...
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Journal articleComputer Communications · September 15, 1999
In this paper, the effect of Web caching on network planning, in the sense of bandwidth computation for the access link interconnecting the ISP's subnet with the Internet, is studied by means of simulations. The latency of a browser retrieving files is stu ...
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Journal articleComputer Communications · June 15, 1999
The performance of prioritized distributed queue dual bus (DQDB) metropolitan area network (MAN) under bursty traffic environment is studied in this article. The tagged node model is adopted to simplify the analysis. The processes of the packet arrivals to ...
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Journal articleIEEE Wireless Communications and Networking Conference Wcnc · January 1, 1999
An RF channel at a cell is assigned to a call during the call set-up process. The channel is dedicated to the subscriber until the call is terminated (normal termination) or the subscriber leaves the cell (handoff). However, the RF channel may fail due to ...
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Journal articleReliability Engineering and System Safety · 1999
The purpose of this paper is to describe an efficient Boolean algebraic algorithm that provides exact solution to the unreliability of a multi-phase mission system where the configurations are described through fault trees. The algorithm extends and improv ...
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Journal articlePerformance Evaluation · January 1, 1999
In a distributed process control system, information about the behavior of physical processes is usually collected and stored in a real-time database which can be remotely accessed by human operators. In this paper we propose an analytic approach to comput ...
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Journal articleReliability Engineering and System Safety · January 1, 1999
In this paper, we propose an integrated reliability/availability modeling and analysis environment suitable for heterogeneous hierarchical system analysis. A key component of this environment is a high level system specification and input language which ac ...
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Journal articleAnnals of Software Engineering · January 1, 1999
The past 20 years have seen the formulation of numerous analytical software reliability models for estimating the reliability growth of a software product. The predictions obtained by applying these models tend to be optimistic due to the inaccuracies in t ...
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Journal articleIEEE Transactions on Software Engineering · January 1, 1999
The purpose of this paper is to describe a method for the simulation of the recently introduced fluid stochastic Petri nets. Since such nets result in rather complex system of partial differential equations, numerical solution becomes a formidable task. Be ...
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Journal articleIEEE Vts 50th Vehicular Technology Conference Vtc 1999 Fall · January 1, 1999
Following Mandayam et al., we define outage events as the channel being attenuated for at least a deterministic period of time, τm. Compared with continuous time Markov chain or discrete time Markov chain, a semi-Markov process (SMP) is general ...
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Journal articleProceedings Annual International Conference on Fault Tolerant Computing · January 1, 1999
Process replication is provided as the central mechanism for application level software fault tolerance in SwiFT and DOORS. These technologies, implemented as reusable software modules, support cold and warm schemes of passive replication. The choice of a ...
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Journal articleProceedings Annual International Conference on Fault Tolerant Computing · January 1, 1999
In this paper, a new algorithm based on Binary Decision Diagrams (BDD) for dependability analysis of distributed computer systems (DCS) with imperfect coverage is proposed. Minimum file spanning trees (MFST) are generated and stored via BDD manipulation. B ...
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Journal articleIEEE Transactions on Computers · December 1, 1998
Preventive maintenance of operational software systems, a novel technique for software fault tolerance, is used specifically to counteract the phenomenon of software "aging." However, it incurs some overhead. The necessity to do preventive maintenance, not ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1998
The phenomenon of software aging refers to the accumulation of errors during the execution of the software which eventually results in it's crash/hang failure. A gradual performance degradation may also accompany software aging. Pro-active fault management ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1998
Software reliability measurement problem can be approached by obtaining the estimates of the residual number of faults in the software. Traditional black-box based approaches to software reliability modeling assume that the debugging process is instantaneo ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1998
Two case studies, one of a terminating application, and the other of a real-time application with feedback control, are presented to illustrate the flexibility offered by discrete-event simulation to analyze complex systems. Data from these studies confirm ...
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Journal articleIEEE Transactions on Reliability · December 1, 1998
This paper presents a simpler and more efficient algorithm (I_VT), based on the one proposed by Veeraraghavan & Trivedi (VT), to calculate system reliability using 'sum of disjoint products' and 'multiple variable inversion' (MVI) techniques. A proposition ...
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Journal articleIEEE Internet Computing · July 1, 1998
Java can be used to create a network computing platform that lets users share applications not specifically devised for the Web. The authors used one such platform to port an existing tool and develop a new application. ...
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Journal articleEuropean Journal of Operational Research · February 16, 1998
In this paper we introduce a new class of stochastic Petri nets in which one or more places can hold fluid rather than discrete tokens. We define a class of fluid stochastic Petri nets in such a way that the discrete and continuous portions may affect each ...
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Journal articlePerformance Evaluation Review · January 1, 1998
Petri nets represent a powerful paradigm for modeling parallel and distributed systems. Parallelism and resource contention can easily be captured and time can be included for the analysis of system dynamic behavior. Most popular stochastic Petri nets assu ...
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Journal articlePerformance Evaluation · January 1, 1998
Stochastic Petri nets have been used to analyze the performance and reliability of complex systems comprising concurrency and synchronization. Various extensions have been proposed in literature in order to broaden their field of application to an increasi ...
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Journal articleJournal of Circuits Systems and Computers · January 1, 1998
Analytical modeling plays a crucial role in the analysis and design of computer systems. Stochastic Petri Nets represent a powerful paradigm, widely used for such modeling in the context of dependability, performance and performability. Many structural and ...
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Journal articleMicroelectronics Reliability · January 1, 1998
Energy management system (EMS) computer architectures have changed significantly over the recent past increasing the difficulty and the need for a priori assessment of system performance and dependability. The old practice based on measurements is no longe ...
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Journal articleMicroelectronics Reliability · January 1, 1998
Mean time to failure (MTTF) is one of the most frequently used dependability measures in practice. By convention, MTTF is the expected time for a system to reach any one of the failure states. For some systems, however, the mean time to absorb to a subset ...
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Journal articleProceedings of the Pacific Rim International Symposium on Fault Tolerant Systems Prfts · December 1, 1997
Fault tolerance is a survival attribute of complex computer systems and software in their ability to deliver continuous service to their users in the presence of faults. Formulating an analytic model for dependability and performance evaluation of hardware ...
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Journal articleProceedings of the Pacific Rim International Symposium on Fault Tolerant Systems Prfts · December 1, 1997
Cache memory is a small, fast, memory system that holds frequently used data. With increasing processor speed, aggressive design practices increase the probability of fault occurrence and the presence of latent errors as processor allows a short duration f ...
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Journal articleProceedings of the International Conference on Computer Communications and Networks ICCCN · December 1, 1997
A combined performance and dependability (called performability) model for dealing with handoff calls is introduced. Stochastic reward nets (SRNs) are used for this purpose. An SRN model of channel assignment is developed and analyzed. The method of phase ...
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Journal articleJournal of Network and Systems Management · January 1, 1997
Detection and restoration times are often ignored when modeling network reliability. In this paper, we develop Markov Regenerative Reward Models (MRRM) to capture the effects of detection and restoration phases of network recovery. States of the MRRM repre ...
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Journal articleIEEE International Conference on Communications · January 1, 1997
As switched networks providing services to end users become more commonplace, integral components of these networks must have an increasing level of dependability. One area of interest is determining the optimal number of network servers required for a swi ...
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Journal articleTelecommunication Systems · January 1, 1997
The B-ISDN will carry a variety of traffic types: the Variable Bit Rate traffic (VBR), of which compressed video is an example, Continuous Bit Rate traffic (CBR), of which telemetry is an example, Data traffic, and Available Bit Rate traffic (ABR) that rep ...
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Journal articleCompass Proceedings of the Annual Conference on Computer Assurance · January 1, 1997
Software reliability is an important metric that quantifies the quality of the software product and is inversely related to the number of unrepaired faults in the system. Fault removal is a critical process in achieving desired level of quality before soft ...
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Journal articleProceedings of the High Assurance Systems Engineering Workshop · January 1, 1997
High-assurance system engineering requires efficient computer-aided dependability evaluation. Although various dependability evaluation techniques and tools have been developed and studied in the last two decades, no adequate attention has been paid to all ...
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Journal articleInternational Workshop on Petri Nets and Performance Models · January 1, 1997
The purpose of this paper is to describe a method for simulation of recently introduced fluid stochastic Petri nets. Since such nets result in rather complex set of partial differential equations, numerical solution becomes a formidable task. Because of a ...
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Journal articleCompass Proceedings of the Annual Conference on Computer Assurance · January 1, 1997
Software rejuvenation is a technique for software fault tolerance which involves occasionally stopping the executing software, `cleaning' the `internal state' and restarting. This cleanup is done at desirable times during execution on a preventive basis so ...
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Journal articleProceedings of the IEEE International Conference on Engineering of Complex Computer Systems ICECCS · December 1, 1996
With the increased attention ATM is receiving to meet the needs of a wide variety of applications, tools are needed to help a network designer focus on the design at hand, rather than to spend time exhaustively learning the tools themselves. This is the co ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1996
A number of analytical software reliability models have been proposed for estimating the reliability growth of a software product. In this paper we present an Enhanced non-homogeneous Poisson process (ENHPP) model and show that previously reported Non-Homo ...
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Journal articleIEEE Transactions on Reliability · December 1, 1996
Two arcs are missing in a figure of Malhotra & Trivedi (1995); these arcs are necessary for the proper functioning of the GSPN. Also, priorities of immediate transitions in that figure must be clearer. This note presents a correctly drawn GSPN and describe ...
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Journal articleIEEE Transactions on Software Engineering · December 1, 1996
Stochastic Pétri net models of large systems that are solved by generating the underlying Markov chain pose the problem of largeness of the state-space of the Markov chain. Hierarchical and iterative models of systems have been used extensively to solve th ...
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Journal articlePerformance Evaluation · October 1, 1996
In this paper we consider the problem of numerical computation of the mean time to failure (MTTF) in Markovian dependability and/or performance models. The problem can be cast as a system of linear equations which is solved using an iterative method preser ...
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Journal articlePerformance Evaluation · January 1, 1996
In this paper we consider the problem of numerical computation of the mean time to failure (MTTF) in Markovian dependability and/or performance models. The problem can be cast as a system of linear equations which is solved using an iterative method preser ...
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Journal articleReliability Engineering and System Safety · January 1, 1996
In this paper, we present a comparative reliability analysis of an application on a corporate B-ISDN network under various alternate-routing protocols. For simple cases, the reliability problem can be cast into fault-tree models and solved rapidly by means ...
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Journal articlePerformance Evaluation Review · January 1, 1996
Checkpointing with rollback-recovery is a well known technique to reduce the completion time of a program in the presence of failures. While checkpointing is corrective in nature, rejuvenation refers to preventive maintenance of software aimed to reduce un ...
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Journal articlePerformance Evaluation · January 1, 1996
In recent studies, the phenomenon of software "aging" has come to light which causes performance of a software to degrade with time. Software rejuvenation is a fault tolerance technique which counteracts aging. In this paper, we address the problem of dete ...
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Journal articleAmerican Statistician · January 1, 1996
We compare the accuracy of two approximate confidence interval estimators for the Bernoulli parameter p. The approximate confidence intervals are based on the normal and Poisson approximations to the binomial distribution. Charts are given to indicate whic ...
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Journal articleProceedings IEEE INFOCOM · January 1, 1996
In this paper we characterize the time-dependent behavior of typical queueing systems that arise in ATM networks under the presense of overloads. Transient queue length distribution and transient cell loss probability are obtained numerically and transient ...
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Journal articleProceedings IEEE International Computer Performance and Dependability Symposium IPDS · January 1, 1996
SHARPE (Symbolic Hierarchical Automated Reliability and Performance Evaluator) is a program that supports the specification and automated solution of reliability and performance models [1]. It contains support for fault trees, reliability block diagrams, r ...
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Journal articleIEEE Proceedings of the National Aerospace and Electronics Conference · January 1, 1996
In order to permit users with little analytic background to evaluate dependability, modeling tools require a user-friendly front end. With this motivation, we have developed a software tool referred to as SDDS for 'Software Dependability for Distributed Sy ...
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Journal articleInternational Workshop on Petri Nets and Performance Models · December 1, 1995
Stochastic Petri Net models of large systems that are solved by generating the underlying Markov chain pose the problem of largeness of the state-space. Hierarchical and iterative models of systems have been used extensively to solve this problem. A proble ...
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Journal articleInternational Workshop on Petri Nets and Performance Models · December 1, 1995
Operating systems which implement a dynamic priority mechanism are very common. Nevertheless, it is very difficult to develop an accurate analytical model to evaluate their performance, mainly due to the different forms of dependency between the various co ...
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Journal articleInternational Workshop on Petri Nets and Performance Models · December 1, 1995
In this paper we present and compare two different approaches for the transient solution of Markov regenerative stochastic Petri Nets: the method based on Markov regenerative theory and the method of supplementary variables. In both cases the equations tha ...
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Journal articleProceedings of the International Symposium on Software Reliability Engineering ISSRE · December 1, 1995
In a client-server type system, the server software is required to run continuously for very long periods. Due to repeated and potentially faulty usage by many clients, such software 'ges' with time and eventually fails. Huang et. al. proposed a technique ...
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Journal articleInternational Workshop on Petri Nets and Performance Models · December 1, 1995
The recent literature on Markov Regenerative Stochastic Petri Nets (MRSPN) assumes that the random firing time associated to each transition is resampled each time the transition fires or is disabled by the firing of a competitive transition. This modeling ...
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Journal articleProceedings IEEE Military Communications Conference MILCOM · December 1, 1995
Detection and restoration times are often ignored when modeling network reliability. In this paper, we develop Markov Regenerative Reward Models (MRRM) to capture the effects of detection and restoration phases of network recovery. States of the MRRM repre ...
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Journal articleMicroelectronics Reliability · January 1, 1995
Dependability modeling plays a major role in the design, validation and maintenance of real-time computing systems. Typical models provide measures such as mean time to failure, reliability and safety as functions of the component failure rates and fault/e ...
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Journal articlePerformance Evaluation · January 1, 1995
Detailed dependability models of various disk array organizations are developed taking into account both the hard disk failures and transient errors. Various error and failure modes of individual disks and the disk array are identified. A small proportion ...
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Journal articleIEEE Transactions on Reliability · January 1, 1995
This paper compares three numerical methods for reliability calculation of Markov, closed, fault-tolerant systems which give rise to continuous-time, time-homogeneous, finite-state, acyclic Markov chains. We consider a modified version of Jensen's method ( ...
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Journal articleIEEE Transactions on Reliability · January 1, 1995
This paper describes a methodology to construct dependability models using generalized stochastic Petri nets (GSPN) and stochastic reward nets (SRN). Algorithms are provided to convert a fault tree (a commonly used combinatorial model type) model into equi ...
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Journal articleProceedings of the Annual Southeast Conference · January 1, 1995
We present a new O(n3) algorithm for seminumerical transient analysis of continuous time Markov chains with n states. The algorithm is based on spectral decomposition of the transition rate matrix in combination with partial fraction expansion b ...
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Journal articleIEEE International Conference on Communications · January 1, 1995
The B-ISDN will carry a variety of traffic types: the Variable Bit Rate traffic (VBR), of which compressed video is an example, Continuous Bit Rate traffic (CBR), of which telemetry is an example, Data traffic, and Available Bit Rate traffic (ABR) that rep ...
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Journal articleProceedings International Computer Performance and Dependability Symposium · January 1, 1995
The Markov Regenerative Stochastic Process (MRGP) has been shown to capture the behavior of real systems with both deterministic and exponentially distributed event times. In this paper we survey the MRGP literature and focus on the different solution tech ...
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Journal articleProceedings Annual International Conference on Fault Tolerant Computing · January 1, 1995
Fault trees and Markov chains are commonly used for dependability modeling. Markov chains are powerful in that various kinds of dependencies can be easily modeled that fault tree models have difficulty capturing, but the state space grows exponentially in ...
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Journal articleNetworks · January 1, 1995
Several algorithms have been developed to solve the reliability problem for nonseries‐parallel networks using the sum of disjoint products (SDP) approach. This paper provides a general framework for most of these techniques. It reviews methods that help im ...
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Journal articleProceedings IEEE INFOCOM · December 1, 1994
In this paper we derive expressions for the time-dependent state probabilities and the time-averaged state-probabilities for the leaky bucket rate control scheme. Our model is based on the theory of Markov regenerative processes. Our results specialize to ...
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Journal articleTheoretical Computer Science · June 6, 1994
Imperfect coverage and nonnegligible reconfiguration delay are known to have a deleterious effect on the dependability and the performance of a multiprocessor system. In particular, increasing the number of processor elements does not always increase depen ...
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Journal articleAnnals of Operations Research · April 1, 1994
We consider the numerical computation of response time distributions for closed product form queueing networks using the tagged customer approach. We map this problem on to the computation of the time to absorption distribution of a finite-state continuous ...
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Journal articleIEEE ACM Transactions on Networking · January 1, 1994
The inherently weak reliability behavior of the ring architecture has led network designers to consider various design choices to improve network reliability. In this paper, we assess the impact of provisions such as node bypass, secondary ring and concent ...
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Journal articleProceedings of the IEEE · January 1, 1994
In this paper, we discuss the role of modeling in the design and validation of life-critical, real time systems. The basics of Markov, Markov reward, and stochastic reward net models are covered. An example of a nuclear power plant cooling system is develo ...
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Journal articleIEEE Transactions on Reliability · January 1, 1994
This paper formally establishes a hierarchy, among the most commonly used types of dependability models, according to their modeling power. Among the combinatorial (non-state-space) model types, we show that fault trees with repeated events are the most po ...
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Journal articlePerformance Evaluation Review · January 1, 1994
Most reliability analysis techniques and tools assume that a system is used for a mission consisting of a single phase. However, multiple phases are natural in many missions. The failure rates of components, system configuration, and success criteria may v ...
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Journal articleIEEE Transactions on Computers · January 1, 1994
The need for the combined performance and reliability analysis of fault tolerant systems is increasing. The common approach to formulating and solving such problems is to use (semi-)Markov reward models. However, the large size of size of state spaces is a ...
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Journal articlePerformance Evaluation · January 1, 1994
Stochastic Petri nets of various types (SPN, GSPN, ESPN, DSPN etc.) are recognized as useful modeling tools for analyzing the performance and reliability of systems. The analysis of such Petri nets proceeds by utilizing the underlying continuous-time stoch ...
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Journal articleMicroelectronics Reliability · January 1, 1994
Three methods for numerical transient analysis of Markov chains, the modified Jensen's method (Jensen's method with steady-state detection of the underlying DTMC and computation of Poisson probabilities using the method of Fox and Glynn [1]), a third-order ...
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Journal articleProceedings of the IEEE International Workshop on Modeling Analysis and Simulation of Computer and Telecommunication Systems · January 1, 1994
Performability and reliability modeling techniques and tools have been an area of intensive research activity in the last ten years. We present a unified mathematical framework for performability and reliability models in terms of Markov reward models. The ...
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Journal articleDigest of Papers International Symposium on Fault Tolerant Computing · January 1, 1994
A high fault detection coverage is very critical for systems with ultra-safe requirements and fault injection is an effective technique for estimating the coverage. One difficulty of fault injection lies in the huge number of injections that need to be car ...
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Journal articleDigest of Papers International Symposium on Fault Tolerant Computing · December 1, 1993
An analytic model is developed for predicting the performance and reliability of mirrored disk subsystems. The model includes Markovian dependencies in the request stream, read and write traffic, unit failures, and individual request failures necessitating ...
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Journal articleundefined · December 1, 1993
The common approach to formulating and solving combined reliability/availability and performance problems is to use Markov reward models. However, the large size of state spaces is a problem that plagues Markovian models. Combinatorial models have been use ...
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Journal articleDiscrete Event Dynamic Systems Theory and Applications · July 1, 1993
Markov reward models (MRMs) are commonly used for the performance, dependability, and performability analysis of computer and communication systems. Many papers have addressed solution techniques for MRMs. Far less attention has been paid to the specificat ...
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Journal articleProceedings of the 1993 ACM Sigmetrics Conference on Measurement and Modeling of Computer Systems Sigmetrics 1993 · June 1, 1993
We consider the sensitivity of transient solutions of Markov models to perturbations in their generator matrices. The perturbations can either be of a certain structure or can be very general. We consider two different measures of sensitivity and derive up ...
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Journal articleIEEE Transactions on Computers · January 1, 1993
The objective of this paper is to describe a technique for computing the distribution of the completion time of a program on a server subject to failure and repair. Several realistic aspects of the system are included in the model. The server behavior is m ...
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Journal articleIEEE Transactions on Software Engineering · January 1, 1993
This paper considers the problem of accurately modeling the software fault-tolerance technique based on recovery blocks. Models of such systems have been criticized for their assumptions of independence. Analysis of some systems have considered the correla ...
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Journal articleIEEE Transactions on Education · January 1, 1993
The study of stochastic modeling can be greatly enriched by the use of computer software. Such software should enable students to experiment with modeling techniques, check their understanding of algorithms for model analysis, develop the skills and “intui ...
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Journal articleProceedings IEEE INFOCOM · January 1, 1993
Five different attachment schemes proposed for the FDDI token ring are compared in terms of reliability. For this purpose, the topologies are first studied in isolation (reliability of the path to the backbone) and subsequently end-to-end user reliabilitie ...
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Journal articleIEEE Transactions on Reliability · January 1, 1993
Performability models of multiprocessor systems and their evaluation are presented. Two cases in which hierarchical modeling is applied are examined. 1. Models are developed to analyze the behavior of processor arrays of various sizes in the presence of pe ...
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Journal articleIEEE Transactions on Parallel and Distributed Systems · January 1, 1993
A client-server system is a distributed system where a server station receives requests from its client stations, processes the requests and returns replies to the requesting stations. In this paper, client-server systems in which a set of workstations acc ...
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Journal articlePerformance Evaluation · January 1, 1993
We present a decomposition approach for the solution of large stochastic reward nets (SRNs) based on the concept of near-independence. The overall model consists of a set of submodels whose interactions are described by an import graph. Each node of the gr ...
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Journal articleJournal of Parallel and Distributed Computing · January 1, 1993
A reliability analysis of various disk array architectures (different levels of RAID) is performed. The dependence of reliability and mean time to data loss on various parameters of a disk array is characterized. A study of these characteristics reveals th ...
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Journal articleProceedings International Conference on Distributed Computing Systems · January 1, 1993
We present a performance analysis of a heterogeneous multiprocessor system where tasks may arrive from Poisson sources as well as by spawning and probabilistic branching of other tasks. Non-preemptive priority scheduling is used between different tasks. We ...
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Journal articleProceedings of the Annual Reliability and Maintainability Symposium · January 1, 1993
Mean time to failure (MTTF) is one of the most frequently used dependability measures in practice. MTTF is the expected time for a system to reach the predefined failure states due to any of the failure causes. If system failures are classified into differ ...
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Journal articleProceedings IEEE INFOCOM · December 1, 1992
The performance of a polling system is modeled by stochastic Petri nets and its analysis is done by numerically solving the underlying Markov chain. One key problem in using stochastic Petri nets for real applications is that the size of underlying Markov ...
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Journal articleJournal of Parallel and Distributed Computing · January 1, 1992
We present two software applications and develop models for them. The first application considers a producer-consumer tasking system with an intermediate buffer task and studies how the performance is affected by different selection policies when multiple ...
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Journal articleMicroelectronics Reliability · January 1, 1992
We discuss unified performance and reliability analysis of a system which operates in a critical environment, in the sense that a catastrophic condition is reached when the accumulated down time exceeds a given threshold. Assuming that the system must proc ...
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Journal articlePerformance Evaluation · January 1, 1992
Composite performance and dependability analysis is gaining importance in the design of complex, fault-tolerant systems. Markov reward models are most commonly used for this purpose. In this paper, an introduction to Markov reward models including solution ...
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Journal articleQueueing Systems · December 1, 1991
We consider queueing systems in which the server occasionally takes a vacation of random duration. The vacation can be used to do additional work; it can also be a rest period. Several models of this problem have been analyzed in the past assuming that the ...
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Journal articlePerformance Evaluation · January 1, 1991
We extend the basic GSPN (generalized stochastic Petri net) model to the GSPN-reward model. This allows the concise specification of both the underlying stochastic process and the rewards attached to the states and the transitions of the stochastic process ...
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Journal articleProceedings of the Annual Reliability and Maintainability Symposium · January 1, 1991
A computer system dependability analysis that ties together concepts such as reliability, maintainability and availability is discussed. Three classes of dependability measures are described: system availability, system reliability, and task completion. Us ...
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Journal articleIEEE Transactions on Reliability · January 1, 1991
The purpose of this paper is to describe an efficient Boolean algebraic algorithm to compute the probability of a union of non-disjoint sets as applied to symbolic reliability analysis. Coherent networks and fault-trees with statistically-independent compo ...
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Journal articleProceedings Symposium on Reliability in Distributed Software and Database Systems · December 1, 1990
An efficient Boolean algebraic algorithm for the symbolic reliability and sensitivity analysis of coherent two-terminal networks with s independent components is described. The algorithm is also applicable to a fault tree model without NOT gates. The algor ...
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Journal articleQueueing Systems · September 1, 1990
We consider a queueing system with two stations served by a single server in a cyclic manner. We assume that at most one customer can be served at a station when the server arrives at the station. The system is subject to service interuption that arises fr ...
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Journal articleCommunications in Statistics Stochastic Models · January 1, 1990
In this paper we derive the distribution of the completion time of a job with a PH-distributed work requirement, on a server modeled by a homogeneous Markov reward process. The interactions between the job in progress and the server are allowed to be eithe ...
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Journal articleCommunications in Statistics Stochastic Models · January 1, 1990
Checkpointing is a technique for reducing the completion (execution) time of long-running batch programs in the presence of failures. It consists of intermittently saving the current status of the program under execution so that if a failure occurs, the pr ...
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Journal articleIEEE Transactions on Computers · January 1, 1990
We present an aggregation method for the computation of transient cumulative measures of large, stiff Markov models. The method is based on the classification of the states of the original problem into slow, fast transient, and fast recurrent states. We ag ...
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Journal articleIEEE Transactions on Computers · January 1, 1990
With the increasing complexity of multiprocessor and distributed processing systems, the need to develop efficient and accurate modeling methods is evident. Fault tolerance and degradable performance of such systems has given rise to considerable interest ...
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Journal articleIEEE Journal on Selected Areas in Communications · January 1, 1990
We consider finite-population and finite-capacity polling systems. The behavior of these systems is described by means of generalized stochastic Petri nets. The exact results for the mean response times are obtained numerically by means of the stochastic P ...
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Journal articlePerformance Evaluation · January 1, 1990
Workload characterization is known to be a difficult and yet a very important facet of performance modeling. User behavior graphs have been advocated as a practical means of workload characterization. Performance modeling with user behavior graphs is for t ...
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Journal articleProceedings of the Hawaii International Conference on System Science · January 1, 1990
A model is developed demonstrating that when availability is the only measure of system effectiveness of interest, even a small reconfiguration delay leads to a violation of the monotonic increase in availability with the number of processors. A measure of ...
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Journal articleAdvances in Computers · January 1, 1990
Dependability calculates the capability of a product to deliver its intended level of service to the user, especially in light of failures or other incidents that impinge on its performance, and combines various underlying ideas, such as reliability, maint ...
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Journal articleundefined · December 1, 1989
A VAXcluster is a closely coupled multicomputer system that consists of two or more VAX computers, one or more hierarchical storage controllers (HSCs), two or more disks, and a star coupler. The Markov model of VAX cluster system availability suffers from ...
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Journal articleProceedings of the International Conference on Parallel Processing · December 1, 1989
The authors address the problem of the completion time of a job structured as a directed acyclic graph processed on parallel processors, i.e., programs consisting of precedence-constrained tasks. The processors are allowed to be subject to failure and repa ...
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Journal articleProceedings Real Time Systems Symposium · December 1, 1989
A novel technique that allows a single system to guarantee the execution of both periodic and aperiodic tasks within hard deadlines is presented. The approach is based on dynamically changing the replication factor of periodic tasks in response to aperiodi ...
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Journal articleundefined · December 1, 1989
SPNP, a powerful GSPN package that allows the modeling of complex system behaviors, is presented. Advanced constructs are available in SPNP such as marking-dependent arc multiplicities, enabling functions, arrays of places or transitions, and subnets; the ...
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Journal articleProceedings International Conference on Distributed Computing Systems · June 1, 1989
The problem of predicting the reliability of a distributed system based on the principles of Byzantine agreement is addressed. The system is considered inoperable or failed if Byzantine agreement cannot be guaranteed. The reliability models depend on a uni ...
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Journal articleEuropean Journal of Operational Research · May 25, 1989
The advent of fault-tolerant, distributed systems has led to increased interest in analytic techniques for the prediction of reliability, availability, and combined performance and reliability measures. Markov and Markov reward models are common tools for ...
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Journal articleORSA Journal on Computing · May 1989
Continuous-time Markov chains (CTMC) are widely used mathematical models. Reliability models, queueing networks, and inventory models all require transient solutions of CTMC. The cost of CTMC transient solution increases with size, stiffness, and ...
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Journal articleCommunications in Statistics Stochastic Models · January 1, 1989
Markov chains and Markov reward models provide are useful for modeling fault-tolerant, distributed and multi-processor systems. In this paper, we consider the transient analysis of “cumulative” or “integral” measures of Markov and Markov reward model behav ...
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Journal articleIEEE Transactions on Computers · January 1, 1989
Several different models for predicting coverage in a faulttolerant system are discussed, including models for permanent, intermittent, and transient errors. Markov, semi-Markov, nonhomogeneous Markov, and extended stochastic Petri net models for computing ...
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Journal articleIEEE Transactions on Computers · January 1, 1989
In this paper, we examine the reliability of an unique-path multistage interconnection network (MIN) and a faulttolerant scheme aimed at improving system reliability. We derive closed-form expressions for the time-dependent reliability of the 8×8 and 16 × ...
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Journal articleIBM Journal of Research and Development · January 1, 1989
Local area networks have been developed using both ring and bus topologies. Multi-loop and multi-connected topologies have been proposed to improve the throughput and dependability of single-loop networks. We evaluate the dependability of a class multi-con ...
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Journal articleIEEE Transactions on Reliability · January 1, 1989
We solve for the availability of an n-processor VAXcluster system using a hierarchical approach that allows us to: 1) obtain a closed-form answer to an apparently difficult problem, and 2) determine the optimal number of processors in the cluster for a giv ...
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Journal articleIEEE Transactions on Reliability · January 1, 1989
Based on the nature of the upper-and lower-bound block diagram models of Multistage Interconnection Networks (MINs), we generalize and consider a series system consisting of independent subsystems. In order to model the reliability of such a system with On ...
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Journal articleJournal of Guidance Control and Dynamics · January 1, 1989
The reliability of digital flight control systems can often be accurately predicted! using Markov chain models. We begin our discussion of flight control system reliability models with definitions of key terms. We then construct a single-fault one-processo ...
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Journal article · December 1, 1988
The Hybrid Automated Reliability Predictor (HARP) is a software package that implements advanced reliability modeling techniques. We present an overview of some of the problems that arise in modeling highly reliable, fault tolerant systems, loosely divided ...
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Journal articleDigest of Papers Ftcs Fault Tolerant Computing Symposium · December 1, 1988
The authors examine the augmented-shuffle-exchange network (ASEN), a network with low switch and link complexity. Using exact reliability expressions for small networks and upper and lower bounds for larger networks, the reliability of the ASEN is compared ...
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Journal articlePerform. Eval. Rev. (USA) · 1988
Traditional evaluation techniques for multiprocessor systems use Markov chains and Markov reward models to compute measures such as mean time to failure, reliability, performance, and performability. In this paper, the authors discuss the extension of Mark ...
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Journal articleComputers and Operations Research · January 1, 1988
We consider the numerical evaluation of Markov model transient behavior. Our research is motivated primarily by computer system dependability modeling. Other application areas include finitecapacity queueing models, closed queueing networks and inventory m ...
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Journal articleIEEE Transactions on Computers · January 1, 1988
Multiprocessor systems can provide higher performance and higher reliability/availability than single-processor systems. In order to properly assess the effectiveness of multiprocessor systems, measures that combine performance and reliability are needed. ...
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Journal articleIEEE Transactions on Computers · January 1, 1988
This paper describes a measurement-based performability model based on error and resource usage data collected on a multiprocessor system. A method for identifying the model structure is introduced and the resulting model is validated against real data. Mo ...
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Journal articleProceedings of the Hawaii International Conference on System Science · January 1, 1988
The authors consider the reliability of the shuffle-exchange multistage interconnection network (SEN) and two variations of this network aimed at improving reliability through fault tolerance. The two variations are the SEN with an extra stage and the redu ...
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Journal article · December 1, 1987
The Hybrid Automated Reliability Predictor (HARP) is a software package that implements advanced reliability modling techniques. In this paper we present an overview of some of the problems that arise in modeling highly reliable, fault tolerant systems, lo ...
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Journal articleAnnals of Operations Research · December 1, 1987
System availability is becoming an increasingly important factor in evaluating the behavior of commercial computer systems. This is due to the increased dependence of enterprises on continuously operating computer systems and to the emphasis on fault-toler ...
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Journal articleAdvances in Applied Probability · December 1987
In this paper we present a general model of the completion time of a single job on a computer system whose state changes according to a semi-Markov process with possibly infinite state-space. When the state of the system changes the job service is ...
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Journal articleSadhana · October 1, 1987
We present an overview of the major problems inherent in reliability modelling of fault-tolerant systems. The problems faced while modelling such systems include the need to consider a very large state space, non-exponential distributions, error analysis, ...
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Journal articleInformation Processing Letters · April 6, 1987
We study the stability condition of an M/G/1 priority queue with two classes of jobs. Class 1 jobs have preemptive priority over class 2 jobs. We consider three different types of preemptions and the effects of possible work loss (due to preemption) on the ...
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Journal articleIEEE Transactions on Software Engineering · January 1, 1987
In this paper we consider the queueing analysis of a faulttolerant computer system. The failure/repair behavior of the server is modeled by an irreducible continuous-time Markov chain. Jobs arrive in a Poisson fashion to the system and are serviced accordi ...
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Journal articleIEEE Transactions on Reliability · January 1, 1987
Conclusions-Combinatorial models such as fault trees and reliability block diagrams are efficient for model specification and often efficient in their evaluation. But it is difficult, if not impossible, to allow for dependencies (such as repair dependency ...
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Journal articleIEEE Transactions on Reliability · January 1, 1987
Conclusions-HARP (the Hybrid Automated Reliability Predictor) is a software package that implements acvanced reliability modeling techniques. We present an overview of some of the problems that arise in modeling highly reliable fault-tolerant systems; the ...
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Journal articleDigest of Papers Ftcs Fault Tolerant Computing Symposium · January 1, 1987
The authors describe the behavior of a multiprocessor system as a continuous-time Markov chain and associate a reward rate (performance measure) with each state. They evaluate the distribution of performability for analytical models of two multiprocessor s ...
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Journal articlePerformance Evaluation · January 1, 1987
Continuous-time Markov chains are commonly used insystem reliability modeling. In this paper, we discuss a method for automatically deriving transient solutions that are symbolic in t for acyclic Markov chains. Our method also includes parametric sensitivi ...
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Journal articleIEEE Transactions on Reliability · January 1, 1987
Conclusions-Reliability is the probability that a system functions according to specifications over a given period of time. During this period, system specifications may allow failures and repairs to occur. This paper considers systems with specifications ...
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Journal articleIEEE Transactions on Software Engineering · January 1, 1987
A graph-based modeling technique has been developed for the stochastic analysis of systems containing concurrency. The basis of the technique is the use of directed acyclic graphs. These graphs represent event-precedence networks where activities may occur ...
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Journal articleundefined · December 1, 1986
Combinatorial models such as fault-trees and reliability block diagrams are efficient in both specification and evaluation of system models, but it is difficult if not impossible to allow for various types of dependency, transient and intermittent faults, ...
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Journal articleActa Informatica · November 1, 1986
In order to aid the designers of life-critical, fault-tolerant computing systems, accurate and efficient methods for reliability prediction are needed. The accuracy requirement implies the need to model the system in great detail, and hence the need to add ...
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Journal articleJournal of Guidance Control and Dynamics · January 1, 1986
In this paper, we present an overview of the hybrid automated reliability predictor (HARP), under development at Duke and Clemson Universities. The HARP approach to reliability prediction is characterized by a decomposition of the overall model into distin ...
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Journal articleIEEE Transactions on Computers · January 1, 1986
An approximation algorithm for systematically converting a stiff Markov chain into a nonstiff chain with a smaller state space is described. After classifying the set of all states into fast and slow states, the algorithm proceeds by further classifying fa ...
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Journal articleJournal of Systems and Software · January 1, 1986
We present an effective technique for the combined performance and reliability analysis of multimode computer systems. A reward rate (or a performance level) is associated with each mode of operation. The switching between different modes is characterized ...
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Journal articlePerformance Evaluation Review · January 1, 1986
Queueing models provide a useful tool for predicting the performance of many service systems including computer systems, telecommunication systems, computer/communication networks and flexible manufacturing systems. Traditional queueing models predict syst ...
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Journal articleIEEE Transactions on Computers · January 1, 1986
Provably conservative (and optimistic) reliability models can be systematically derived from more complex models. These derived models incorporate a reduced state space and fewer transitions and, therefore, have solutions that are more cost-effective than ...
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Journal articleIFAC Proceedings Series · January 1, 1986
Dependability measures (such as reliability, mean time to failure, availability) are important criteria for the design of computer-based applications, as well as for their validation. In this paper important techniques for dependability modeling are discus ...
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Journal articleDigest of Papers Ftcs Fault Tolerant Computing Symposium · January 1, 1986
Fault-tolerant computer systems change their level of performance (e. g, mode of operation or service rate) in response to different events such as failure, degradation or repair. The authors present a unified model for the analysis of job (task) completio ...
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Journal articleDigest of Papers Ftcs Fault Tolerant Computing Symposium · January 1, 1986
The system availability estimator (SAVE) program package is described that can be used for constructing and solving probabilistic models of computer system availability and reliability. SAVE is a state-of-the-art tool intended for use during system design ...
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Journal articleundefined · December 1, 1985
A description is given of the philosophical differences between three current SPN models in an attempt to merge the most important (and noncontradictory) aspects into one. This work previews the design of a package for the solution of this unified model. ...
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Journal articleundefined · December 1, 1985
An Extended Stochastic Petri Net (ESPN) model, useful for modeling systems which exhibit concurrent, asynchronous, or nondeterministic behavior is developed. Applications demonstrating the flexibility of the model for a variety of system modeling applicati ...
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Journal articleIEEE Transactions on Computers · January 1, 1985
In order to remain tractable, many reliabilitymod-els do not include the states-and transitions necessary to represent fault/error-handling details. Instead, the effectiveness of fault/ error-handling mechanisms is represented by the use ofinstanta-neous c ...
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Journal articleOperations Research Letters · January 1, 1985
We consider a single server first in first out queue in which each arriving task has to be completed within a certain period of time (its deadline). More precisely, each arriving task has its own deadline - a non-negative real number - and as soon as the r ...
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Journal articleModeling and Simulation Proceedings of the Annual Pittsburgh Conference · December 1, 1984
We detail the use of behavioral decomposition in modeling systems that contain state transitions having widely disparate time constants. We show that such decomposition leads naturally to hybrid system models, containing both analytic and simulative submod ...
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Journal articleundefined · December 1, 1984
Important problems that arise in modeling highly-reliable fault-tolerant systems are discussed. First, reliability models of such systems possess a large number of states, making the solution computationally intractable. This leads to the need for decompos ...
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Journal articleModeling and Simulation Proceedings of the Annual Pittsburgh Conference · December 1, 1984
The need for increased reliability and computing power coupled with advances in technology has given rise to sizeable and complex computer systems. The users and designers of such systems need tools to evaluate the effectiveness of such systems. Current ap ...
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Journal articleJournal of Systems and Software · May 1, 1984
We present an effective technique for the combined performance and reliability analysis of multimode computer systems. A reward rate (or a performance level) is associated with each mode of operation. The switching between different modes is characterized ...
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Journal articleBehaviour and Information Technology · January 1, 1984
Ergonomics in India is a newly emerging discipline-having made inroads to the people of India very recently. Most of the Indians are absolutely unaware of using ergonomics to achieve an efficient man-machine-environment system for better productivity with ...
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Journal articleComputers and Electrical Engineering · January 1, 1984
Current technology allows sufficient redundancy in fault-tolerant computer systems to insure that the failure probability due to exhaustion of spares is low. Consequently, the major cause of failure is the inability to correctly detect, isolate, and reconf ...
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Journal articleActa Informatica · September 1, 1983
This paper examines task allocation in fault-tolerant distributed systems. The problem is formulated as a constrained sum of squares minimization problem. The computational complexity of this problem prompts us to consider an efficient approximation algori ...
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Journal articleIEEE Transactions on Reliability · January 1, 1983
Summary & Conclusions:—Two important problems which arise in modeling fault-tolerant systems with ultra-high reliability requirements are discussed. 1) Any analytic model of such a system has a large number of states, making the solution computationally in ...
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Journal articleIEEE Transactions on Computers · January 1, 1983
A review and a critical evaluation of a representative class of state-of-the-art models for ultrahigh reliability prediction is presented. This evaluation naturally leads us to a new model for ultrahigh reliability prediction now under development. The new ...
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Journal articleIEEE Transactions on Computers · January 1, 1983
Analytic queueing models of programs with internal concurrency are considered. The program behavior model allows a process to spawn two or more concurrent tasks at some point during its execution. Except for queueing effects, the tasks execute independentl ...
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Journal articleProceedings Symposium on Reliability in Distributed Software and Database Systems · December 1, 1982
Task and file allocation are examined in two classes of fault-tolerant distributed systems. The task allocation problem arises in software-implemented fault tolerance (SIFT)-like systems, while the file allocation problem arises in Ethernet-like systems. B ...
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Journal articleIEEE Transactions on Computers · January 1, 1982
An optimization model is developed for assigning a fixed set of files across an assemblage of storage devices so as to maximize system throughput. Multiple levels of executable memories and distinct record sizes for separate files are allowed. Through the ...
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Journal articleIEEE Transactions on Computers · January 1, 1982
Computer performance models of parallel processing systems in which a job subdivides into two or more tasks at some point during its execution are considered. Except for queueing effects, the tasks execute independently of one another and do not require sy ...
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Journal articleComputer Performance · January 1, 1982
A computer configuration design problem is considered. The computer system is modelled as a closed queueing network. The average response time to an interactive user request is minimized and the speeds of the devices are the decision variables. A broad cla ...
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Journal articleNASA Contractor Reports · December 1, 1981
CARE III is a major departure from conventional approaches to reliability modeling in that it purports to support nonexponential distributions, while avoiding the problem of large state spaces through the use of state aggregation. More specifically, CARE I ...
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Journal articleJournal of the ACM Jacm · April 1, 1981
The performance-oriented design of linear storage hierarchies whtch are operating m muluprogramming environments is considered An optimization model is superimposed upon an exponential queuing network model of the hierarchy, yielding a problem whose object ...
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Journal articleNASA Contractor Reports · January 1, 1981
CARE III is a major departure from conventional approaches to reliability modeling in that it purports to support nonexponential distributions, while avoiding the problem of large state spaces through the use of state aggregation. More specifically, CARE I ...
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Journal articleJournal of the ACM Jacm · July 1, 1980
This paper presents a computer system configuration design problem in which the objective is to select the CPU speed, the capacities of secondary storage devices, and the allocation of a set of files across the secondary storage devices so as to maximize t ...
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Journal articlePerformance Evaluation Review · January 1, 1980
A previous model for computer system configuration planning is extended. The problem is to optimally select the CPU speed, the device capacities, and file assignments so as to maximize throughput subject to a fixed cost constraint. This essentially discret ...
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Journal articleEASCON Record IEEE Electronics and Aerospace Systems Convention · January 1, 1980
Design requirements of systems used in life-critical applications result in the specification of extremely high levels of reliability. A case in point is the digital flight control system to be used in the future generation of aircraft. Traditional reliabi ...
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Journal articleNational Bureau of Standards Special Publication · January 1, 1980
This work extends a previous model for computer system configuration planning developed by the authors. The problem is to optimally select CPU speed, device capacities, and file assignments so as to maximize system throughput subject to a fixed cost constr ...
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Journal articleComputing · September 1, 1979
Prepaging is advocated as a technique to reduce the excessive page traffic due to the changes in the phases of execution of a program. Common prepaging techniques are surveyed. It is advocated that the phase transition behavior cannot be adequately predict ...
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Journal articleIEEE Transactions on Software Engineering · January 1, 1979
This paper considers a computer configuration design problem. The computer system is modeled by a closed queuing network. The system throughput is the objective function to be maximized and the speed of the devices are the decision variables. A rich class ...
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Journal articleTransactions of the American Association of Cost Engineers · January 1, 1978
This paper determines the speed of the devices constituting a computer system which will maximize system throughput given a fixed budget. The system composed of a central processor and peripheral devices is modeled as a closed queueing network of exponenti ...
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Journal articleundefined · January 1, 1978
A case study in the use of closed queuing network models for the design and analysis of an interactive distributed computer system as applicable to a military computer system as applicable to a military command and control system is presented. Such a proje ...
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Journal articleundefined · January 1, 1978
A formal proof of correctness of the on-line division algorithm specified in an earlier paper is presented. Two radix 4 on-line division algorithms, with non-redundant and redundant operands respectively, are also derived. ...
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Journal articleHigh Speed Computer and Algorithm Organization · 1977
The Control Data Corporation (CDC) STAR (STring ARray) computer is a high performance vector machine capable of performing up to 100 million operations per second. Although the size of the main memory is limited to either 1/2 million or 1 million 64-bit wo ...
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Journal articleIEEE Transactions on Computers · January 1, 1977
Data paging is of primary concern for problems with large data bases and for many types of array problems. We show that prepaging reduces the paging problems of array algorithms operating on large arrays. We also show that the use of a submatrix algorithm ...
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Journal articleIEEE Transactions on Computers · January 1, 1977
Recently, there has been some interest in the use of continued fractions for digital hardware calculations. We require that the coefficients of the continued fractions be integral powers of 2 and, therefore, well-known continued fraction expansions of func ...
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Journal articleIEEE Transactions on Computers · January 1, 1977
In this paper, on-line algorithms for division and multiplication are developed. It is assumed that the operands as well as the result flow through the arithmetic unit in a digit-by-digit, most significant digit first fashion. The use of a redundant digit ...
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Journal articleIEEE Transactions on Computers · 1977
Data paging is of primary concern for problems with large data bases and for many types of array problems. It is shown that prepaging reduces the paging problems of array algorithms operating on large arrays. Also shown is that the use of a submatrix algor ...
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Journal articleIEEE Transactions on Computers · January 1, 1976
A demand prepaging algorithm DPMIN is defined and proved to be an optimal demand prepaging algorithm. However, it cannot be used in practice since it requires that the future reference string be completely known in advance. Several practical prepaging algo ...
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Journal articleProceedings Symposium on Computer Arithmetic · January 1, 1975
Recently, there has been some interest in the use of continued fractions for digital hardware calculat ions. We require t h a t the coefficients of the continued fractions be integral powers of two. As a result well known continued fraction expansions of f ...
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Journal articleIEEE Transactions on Computers · January 1, 1973
The purpose of this paper is to demonstrate that represen tations of numbers other than positional notation may lead to practical hardware realizations for digital calculation of classes of algorithms. This paper describes current research in the use of co ...
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