The usage of advanced audio processing algorithms in products has always been limited by the available processing power. For powerful concepts like the wave field synthesis (WFS) the performance is limited by the exec...
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The usage of advanced audio processing algorithms in products has always been limited by the available processing power. For powerful concepts like the wave field synthesis (WFS) the performance is limited by the execution speed. In the past it was possible to increase the performance of digital signal processors by increasing the clock rate. The next generation will be highly parallel heterogeneous multi-processor systems. This paper presents a now parallel processor architecture and the first stops towards an adequate optimization of WFS. A software development environment which assists in creating scalable programs for highly parallel hardware will be further explained. An enhanced WFS convolution structure is presented which use position dependent filtering and improve the interpolation necessary for moving sound sources.
Bloom's taxonomy of the cognitive domain and the SOLO taxonomy are being increasingly widely used in the design and assessment of courses, but there are some drawbacks to their use in computer science. This paper ...
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ISBN:
(纸本)9781450378420
Bloom's taxonomy of the cognitive domain and the SOLO taxonomy are being increasingly widely used in the design and assessment of courses, but there are some drawbacks to their use in computer science. This paper reviews the literature on educational taxonomies and their use in computer science education, identifies some of the problems that arise, proposes a new taxonomy and discusses how this can be used in application-oriented courses such as programming.
Reactive real-time systems have to react to external events within time constraints: Triggered tasks must execute within deadlines. It is therefore important for the designers of such systems to analyze the schedulabi...
Reactive real-time systems have to react to external events within time constraints: Triggered tasks must execute within deadlines. It is therefore important for the designers of such systems to analyze the schedulability of tasks during the design process, as well as to test the system's response time to events in an effective manner once it is implemented. This article explores the use of genetic algorithms to provide automated support for both tasks. Our main objective is then to automate, based on the system task architecture, the derivation of test cases that maximize the chances of critical deadline misses within the system; we refer to this testing activity as stress testing. A second objective is to enable an early but realistic analysis of tasks' schedulability at design time. We have developed a specific solution based on genetic algorithms and implemented it in a tool. Case studies were run and results show that the tool (1) is effective at identifying test cases that will likely stress the system to such an extent that some tasks may miss deadlines, (2) can identify situations that were deemed to be schedulable based on standard schedulability analysis but that, nevertheless, exhibit deadline misses.
An algorithm for time division multiple access (TDMA) is found to be applicable in converting existing distributed algorithms into a model that is consistent with sensor networks. Such a TDMA service needs to be self-...
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Reactive real-time systems have to react to external events within time constraints: Triggered tasks must execute within deadlines. It is therefore important for the designers of such systems to analyze the schedulabi...
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Reactive real-time systems have to react to external events within time constraints: Triggered tasks must execute within deadlines. It is therefore important for the designers of such systems to analyze the schedulability of tasks during the design process, as well as to test the system's response time to events in an effective manner once it is implemented. This article explores the use of genetic algorithms to provide automated support for both tasks. Our main objective is then to automate, based on the system task architecture, the derivation of test cases that maximize the chances of critical deadline misses within the system;we refer to this testing activity as stress testing. A second objective is to enable an early but realistic analysis of tasks' schedulability at design time. We have developed a specific solution based on genetic algorithms and implemented it in a tool. Case studies were run and results show that the tool (1) is effective at identifying test cases that will likely stress the system to such an extent that some tasks may miss deadlines, (2) can identify situations that were deemed to be schedulable based on standard schedulability analysis but that, nevertheless, exhibit deadline misses.
Parallel asynchronous iterative algorithms relax synchronization and communication requirements, and can potentially extend Desktop Grids beyond embarrassingly parallel applications to support a broader class of paral...
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Message Passing is a popular mechanism used to enable inter-process communication in parallel and distributed computing. Many complex scientific and engineering applications that are executed on clusters have been dev...
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A stress test methodology aimed at increasing chances of discovering faults related to network traffic in distributed systems is presented. The technique uses the UML 2.0 model of the distributed system under test, au...
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ISBN:
(纸本)1595933751
A stress test methodology aimed at increasing chances of discovering faults related to network traffic in distributed systems is presented. The technique uses the UML 2.0 model of the distributed system under test, augmented with timing information, and is based on an analysis of the control flow in sequence diagrams. It yields stress test requirements that are made of specific control flow paths along with time values indicating when to trigger them. Different variants of our stress testing technique already exist (they stress different aspects of a distributed system) and we focus here on one variant that is designed to identify and to stress test the system at the instant when data traffic on a network is maximal. Using a real-world distributed system specification, we design and implement a prototype distributed system and describe, for that particular system, how the stress test cases are derived and executed using our methodology. The stress test results indicate that the technique is significantly more effective at detecting network traffic-related faults when compared to test cases based on an operational profile. Copyright 2006 ACM.
This paper reports on the construction and validation of fault-proneness prediction models in the context of an object-oriented, evolving, legacy system. The goal is to help QA engineers focus their limited verificati...
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ISBN:
(纸本)1595932186
This paper reports on the construction and validation of fault-proneness prediction models in the context of an object-oriented, evolving, legacy system. The goal is to help QA engineers focus their limited verification resources on parts of the system likely to contain faults. A number of measures including code quality, class structure, changes in class structure, and the history of class-level changes and faults are included as candidate predictors of class fault-proneness. A cross-validated classification analysis shows that the obtained model has less than 20% of false positives and false negatives, respectively. However, as shown in this paper, statistics regarding the classification accuracy tend to inflate the potential usefulness of the fault-proneness prediction models. We thus propose a simple and pragmatic methodology for assessing the cost-effectiveness of the predictions to focus verification effort. On the basis of the cost-effectiveness analysis we show that change and fault data from previous releases is paramount to developing a practically useful prediction model. When our model is applied to predict faults in a new release, the estimated potential savings in verification effort is about 29%. In contrast, the estimated savings in verification effort drops to 0% when history data is not included. Copyright 2006 ACM.
Analysis and design by contract allows the definition of a formal agreement between a class and its clients, expressing each party's rights and obligations. Contracts written in the Object Constraint Language (OCL...
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