209,829 research outputs found

    Reliability Prediction and Web Service Selection Using Soft Computing Techniques for Service-Oriented Systems

    Get PDF
    Building a wide variety of distributed systems is a complex task these days. Since, service oriented architecture (SOA) is a major framework for distributed systems, it’s reliability is the major concern while developing a related software. The assessment of reliability in service-oriented systems (SOS) mainly depends on the accessibility of web-services, which leans on different parameters i.e. unpredictable internet, communication links and the location of web services. Hence, reliability needs to be predicted for the better functioning of a system. Selection of an optimal web-service is also an important concern in SOS. Since, for an abstract task to perform in SOS, a large number of functionally equivalent web service candidates are available. The same web service candidate can perform differently with different users. So, a technique is required for building the personalized web service ranking framework for designers. Hence, for predicting the reliability of SOS and for selection of an optimal web service candidate from functionally equivalent set of web service candidates a most effective approach is desired. In this work, a novel methodology is proposed for predicting the reliability of Web Service candidate which basically uses the past failure experience of similar service users and a personalized framework for selection of an optimal Web Service candidate from functionally equivalent candidates' set which basically is associated with the past Web-Service usage experience of similar users. In this work, no additional invocation of Web service is required. The experimental results are compared with many other techniques proposed by other authors in literature which shows the effectiveness of proposed approach

    Rigorously assessing software reliability and safety

    Get PDF
    This paper summarises the state of the art in the assessment of software reliability and safety ("dependability"), and describes some promising developments. A sound demonstration of very high dependability is still impossible before operation of the software; but research is finding ways to make rigorous assessment increasingly feasible. While refined mathematical techniques cannot take the place of factual knowledge, they can allow the decision-maker to draw more accurate conclusions from the knowledge that is available

    A Survey of Prediction and Classification Techniques in Multicore Processor Systems

    Get PDF
    In multicore processor systems, being able to accurately predict the future provides new optimization opportunities, which otherwise could not be exploited. For example, an oracle able to predict a certain application\u27s behavior running on a smart phone could direct the power manager to switch to appropriate dynamic voltage and frequency scaling modes that would guarantee minimum levels of desired performance while saving energy consumption and thereby prolonging battery life. Using predictions enables systems to become proactive rather than continue to operate in a reactive manner. This prediction-based proactive approach has become increasingly popular in the design and optimization of integrated circuits and of multicore processor systems. Prediction transforms from simple forecasting to sophisticated machine learning based prediction and classification that learns from existing data, employs data mining, and predicts future behavior. This can be exploited by novel optimization techniques that can span across all layers of the computing stack. In this survey paper, we present a discussion of the most popular techniques on prediction and classification in the general context of computing systems with emphasis on multicore processors. The paper is far from comprehensive, but, it will help the reader interested in employing prediction in optimization of multicore processor systems

    Design diversity: an update from research on reliability modelling

    Get PDF
    Diversity between redundant subsystems is, in various forms, a common design approach for improving system dependability. Its value in the case of software-based systems is still controversial. This paper gives an overview of reliability modelling work we carried out in recent projects on design diversity, presented in the context of previous knowledge and practice. These results provide additional insight for decisions in applying diversity and in assessing diverseredundant systems. A general observation is that, just as diversity is a very general design approach, the models of diversity can help conceptual understanding of a range of different situations. We summarise results in the general modelling of common-mode failure, in inference from observed failure data, and in decision-making for diversity in development.

    Do System Test Cases Grow Old?

    Full text link
    Companies increasingly use either manual or automated system testing to ensure the quality of their software products. As a system evolves and is extended with new features the test suite also typically grows as new test cases are added. To ensure software quality throughout this process the test suite is continously executed, often on a daily basis. It seems likely that newly added tests would be more likely to fail than older tests but this has not been investigated in any detail on large-scale, industrial software systems. Also it is not clear which methods should be used to conduct such an analysis. This paper proposes three main concepts that can be used to investigate aging effects in the use and failure behavior of system test cases: test case activation curves, test case hazard curves, and test case half-life. To evaluate these concepts and the type of analysis they enable we apply them on an industrial software system containing more than one million lines of code. The data sets comes from a total of 1,620 system test cases executed a total of more than half a million times over a time period of two and a half years. For the investigated system we find that system test cases stay active as they age but really do grow old; they go through an infant mortality phase with higher failure rates which then decline over time. The test case half-life is between 5 to 12 months for the two studied data sets.Comment: Updated with nicer figs without border around the

    The problems of assessing software reliability ...When you really need to depend on it

    Get PDF
    This paper looks at the ways in which the reliability of software can be assessed and predicted. It shows that the levels of reliability that can be claimed with scientific justification are relatively modest
    corecore