This paper is based on a workshop held at the University of Southern California Center for softwareengineering in March, 2002. The components of the Capability Maturity Model IntegrationSM (CMMISM) systems Engineerin...
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Adaptive Quality-of-Service management is critical for enabling effective collaboration between distributed clients in a heterogeneous (wired and wireless) environment. This is because both client profiles (capabiliti...
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This paper presents the design and evaluation of an adaptive system sensitive partitioning and load balancing framework for distributed adaptive mesh refinement applications on heterogeneous and dynamic cluster enviro...
This paper presents the design and evaluation of an adaptive system sensitive partitioning and load balancing framework for distributed adaptive mesh refinement applications on heterogeneous and dynamic cluster environments. The framework uses system capabilities and current system state to select and tune appropriate partitioning parameters (e.g., partitioning granularity, load per processor) to maximize overall application performance. Furthermore, it uses dynamic load sensing (using NWS) to adapt to the load dynamics in the cluster.
We present a methodology and a tool to support test selection from regression test suites based on change analysis in object-oriented designs. We assume that designs are represented using the Unified Modeling Language...
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We present a methodology and a tool to support test selection from regression test suites based on change analysis in object-oriented designs. We assume that designs are represented using the Unified Modeling Language (UML) and we propose a formal mapping between design changes and a classification of regression test cases, i.e., three categories: reusable, retestable, and obsolete. We provide evidence of the feasibility of the methodology and its usefulness by using our prototype tool on an industrial case study.
With computersystems becoming ever larger and more complex, the cost and effort associated with their construction is increasing and the systems are now sufficiently complex that developers need help to analyse and u...
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With computersystems becoming ever larger and more complex, the cost and effort associated with their construction is increasing and the systems are now sufficiently complex that developers need help to analyse and understand them. However, at design time, when this understanding is crucial, the system is unavailable because it has yet to be built. Formal, executable models can help with this problem by providing developers with a platform on which to establish the feasibility of a proposed design. However, commercial developers seem reluctant to employ this type of modelling in their design activity. This paper describes a modelling tool in which the traditional model generation technique of writing "programming language like" code is replaced with a model generation tool which uses a graphical representation of models whilst retaining sufficient formality to permit the models to be executed, or converted into code for analysis by a traditional model checking tool.
The overall quality of network connections has a significant impact on the performance of networked applications. Consequently, QoS management for networked multimedia applications over IP is a significant and immedia...
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The overall quality of network connections has a significant impact on the performance of networked applications. Consequently, QoS management for networked multimedia applications over IP is a significant and immediate challenge. While differentiated services (diffserv) provide a sense of resource allocation and QoS, they do not guarantee QoS. This paper presents design, implementation and evaluation of a content-aware bandwidth broker (CABB) that manages QoS of multimedia applications for the diffserv environment. CABB allocates network resources to multimedia flows based on client requirement and the tolerance and adaptability of the application. CABB has been implemented and evaluated using the NS-2 simulator toolkit. Evaluations show that CABB improves network resource allocations and increases overall throughput. The results also show that multimedia flows are better managed and controlled, thereby improving perceived QoS and avoiding possible congestion in core routers.
A number of strategies have been proposed for state-based class testing. An important proposal made by Chow (1978), that was subsequently adapted by Binder (1999), consists in deriving test sequences covering all roun...
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A number of strategies have been proposed for state-based class testing. An important proposal made by Chow (1978), that was subsequently adapted by Binder (1999), consists in deriving test sequences covering all round-trip paths in a finite state machine (FSMs). Based on a number of (rather strong) assumptions, and for traditional FSMs, it can be demonstrated that all operation and transfer errors in the implementation can be uncovered. Through experimentation, this paper investigates this strategy when used in the context of UML statecharts. Based on a set of mutation operators proposed for object-oriented code we seed a significant number of faults in an implementation of a specific container class. We then investigate the effectiveness of four test teams at uncovering faults, based on the round-trip path strategy, and analyze the faults that seem to be difficult to detect. Our main conclusion is that the round-trip path strategy is reasonably effective at detecting faults (87% average as opposed to 69% for size-equivalent, random test cases) but that a significant number of faults can only exhibit a high detection probability by augmenting the round-trip strategy with a traditional black-box strategy such as category-partition testing. This increases the number of test cases to run -and therefore the cost of testing- and a cost-benefit analysis weighting the increase of testing effort and the likely gain in fault detection is necessary.
This paper explores three different methods, employed separately and in combination, to improve the quality of video delivery on wireless local area networks. The approaches are: leader-driven multicast (LDM), monitor...
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ISBN:
(纸本)0780373715
This paper explores three different methods, employed separately and in combination, to improve the quality of video delivery on wireless local area networks. The approaches are: leader-driven multicast (LDM), monitoring MAC layer unicast (re)transmissions by other receivers; application-level forward error correction (FEC) using block erasure codes; negative feedback from selected receivers in the form of extra parity requests (EPR). The performance of these three methods is evaluated using both experiments on a mobile computing testbed and simulation. The results indicate that, while LDM is helpful in improving the raw packet reception rate, the combination of FEC and EPR is most effective in improving the frame delivery rate.
In softwareengineering, design patterns propose solution skeletons for common design problems. The solution skeleton is described in such a way that the design can be used for other projects, where each application t...
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In softwareengineering, design patterns propose solution skeletons for common design problems. The solution skeleton is described in such a way that the design can be used for other projects, where each application tailors the design to specific project constraints. This paper describes research into investigating how a similar approach to reuse can be applied to requirements specifications, which we term requirements patterns. Specifically, the paper explores how object-oriented modeling notations, such as the Unified Modeling Language (UML), can be used to represent common requirements patterns. Structural and behavioral information are captured as part of a requirements pattern. In order to maximise reuse, we focus on requirements patterns for embedded systems. This paper also describes case studies that illustrate how we have applied these general patterns to multiple embedded systems applications from the automotive industry.
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