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Software Engineering Journal

Issue 1 • Date Jan 1992

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Displaying Results 1 - 7 of 7
  • An empirical evaluation (and specification) of the all-du-paths testing criterion

    Page(s): 43 - 51
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    The all-du-paths structural testing criterion is one of the most discriminating of the data-flow testing criteria. Unfortunately, in the worst case, the criterion requires an intractable number of test cases. In a case study of an industrial software system, it is found that the worst-case scenario is rare. Eighty percent of the subroutines require ten or fewer test cases. Only one subroutine out of 143 requires an intractable number of tests. However, the number of required test cases becomes tractable when using the all-uses criterion. The authors include a formal specification of both the all-du-paths criterion and the software tools used to estimate a minimal number of test cases necessary to meet the criterion View full abstract»

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  • Achieving high integrity of process control software by graphical design and formal verification

    Page(s): 53 - 64
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    The International Electrotechnical Commission is standardising four compatible languages for designing and implementing programmable logic controllers (PLCs). The language family includes a diagrammatic notation that supports the idea of software ICs to encourage graphical design techniques and systematic software reuse. The authors present an interactive system with a graphical interface for constructing and validating PLC software. The semantics of a graphical design is defined by a mapping associating each design with an executable formal specification. The specification provides the basis for rigorous proofs and early tests of critical properties of a new design. A realistic example illustrates these features View full abstract»

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  • File system caching in large point-to-point networks

    Page(s): 65 - 80
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    The design of a file system for a general-purpose scalable parallel computing engine, based on an extensible mesh of processors is examined. Although many distributed file systems have already been developed, none have properly addressed the characteristics that are special to these computing engines, namely dynamic load-balancing and point-to-point networks. Client caching is identified as a key area where current systems fall short. The authors propose two new caching schemes, that employ an extra level of caching in addition to that used by current client caching schemes. They present some results from a simulation study of the two new caching schemes, which demonstrate that the schemes outperform traditional client caching schemes when used in a general-purpose processor mesh-based, parallel computing engine. Since one of these caching schemes is quite complex, a formal specification in the Z language has been developed View full abstract»

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  • The complexity of software testing

    Page(s): 13 - 24
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    The futility of using a general-purpose metric to characterise `the' complexity of a program has been argued to support the design of specific metrics for the different stages of the software life-cycle. An analysis of the module testing activity is performed, providing evidence of the absurdity of all-purpose metrics, as well as a methodical means with which to measure testing complexity. Several standard metrics are seen to serve as component measures for the intricacies of testing. The methodology is applied to compare traditional and adaptive means of testing. It is shown that previous informal arguments asserting the superiority of adaptive methodologies are formally confirmed View full abstract»

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  • Modelling of visualised data-flow diagrams using Petri net model

    Page(s): 4 - 12
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (876 KB)  

    An approach to the modelling and implementation of data-flow diagrams (DFDs) using Petri nets is introduced. A direction is identified where visualisation and high-level semantics can be incorporated into data-flow diagrams to facilitate direct manipulation, interpretation and validation. At the automation level, visualised DFDs generate layouts for data-flow vectors and use Petri nets to safeguard the correctness of a specification. The Petri net model uses a set of constraints to enforce consistency, both within and across diagrams. Al the visual level, visualised DFDs replace the traditional textual specifications of the process and data-flow components with graphical forms. The entity-relationship model is adopted as the hierarchical and logical view of data View full abstract»

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  • Two object-based decomposition methodologies: a case study

    Page(s): 35 - 42
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    An interesting and little documented problem is the influence of a design methodology on program architecture. In the case study, the authors compared two design methodologies and their impact on both development process and the resulting program architecture. The methodologies are object-based variants of refinement methodology and structured design, respectively. Both methodologies were applied to the same problem (a library system of less than 1000 lines of Ada code), and the results were compared. Substantial differences between the two resulting architectures are analyzed and discussed View full abstract»

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  • Vista: a user interface for a distributed object-oriented software engineering environment

    Page(s): 25 - 34
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1268 KB)  

    A prototype user interface for a distributed software engineering environment is described, where the components of the environment are autonomous agents with some inherent decision-making capabilities. Agents may be distributed across a local- or wide-area network. Two forms of interaction are supported; namely, direct manipulation and message passing. Synchronous interaction is supported via the direct manipulation of system objects. Asynchronous interaction is managed by a central server agent, distributing electronic mail messages to the appropriate human or automated agents. The functionality of the system is illustrated by examples drawn from the domain of software development View full abstract»

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