Final report on the farmer's aid in plant disease diagnoses

This report is the final report on the FAD project. The FAD project was initiated in september 1985 to test the expert system shell Babylon by developing a prototype crop disease diagnosis system in it. A short overview of the history of the project and the main problems encountered is given in chapter 1. Chapter 2 describes the result of an attempt to integrate JSD with modelling techniques like generalisation and aggregation and chapter 3 concentrates on the method we used to elicit phytopathological knowledge from specialists. Chapter 4 gives the result of knowledge acquisition for the 10 wheat diseases most commonly occurring in the Netherlands. The user interface is described briefly in chapter 5 and chapter 6 gives an overview of the additions to the implementation we made to the version of FAD reported in our second report. Chapter 7, finally, summarises the conclusions of the project and gives recommendations for follow-up projects

Formalized structured analysis specifications

Specifications define systems. The definition of a system can be stated casually or formally. A formal specification is a mathematically precise definition of software functionality. Informal specifications are less precise definitions of software functionality. The benefits of formal specifications are clear. Arguments against the use of formal specifications have been refuted;Several formal specification techniques are available for specifying imperative programs, e.g., Z, VDM, and SPECS. Most specification techniques for distributed/concurrent systems concentrate on low level issues, e.g., deadlock and synchronization;Structured Analysis (SA) specifications are a popular informal specification technique, but they lack a rigorous mathematical semantics. SA specifications are based on a graphical syntax with little underlying formal structure. In this thesis, we identify and formalize those underlying structures that are represented informally, provide a formal definition of a SA specification, develop formal interpretations for those components of SA specifications that are subject to varying interpretation, and define an operational semantics for animating SA specifications. The resulting formalized SA specifications are mathematically precise and can be used to specify distributed/concurrent systems

Integrating Human Factors with Structured Analysis and Design Methods

Current human factors input to system development is effected through methods, tools and guidelines. Although the input prompts the consideration of human factors concerns during system design, reports have highlighted inadequacies with respect to the scope, granularity, format and timing of the contributions, e.g. Smith, 1986; Chapanis and Burdurka, 1990; Sutcliffe, 1989; etc. The thesis argues that such problems are obviated if design needs of both Software Engineering and Human Factors are appropriately represented within an overall system design cycle. Intersecting concerns may then be identified for explicit accommodation by the design agenda. To derive an overall design cycle, current conceptions for the individual disciplines should be examined. Since these conceptions are expressed at a lower level as methods, an overall design cycle may be instantiated more specifically by integrating compatible methods from the two disciplines. Methodological integration is desirable as design inter-dependencies and roles may be defined explicitly. More effective inter-disciplinary communication may also accrue from the use of a common set of notations. Methodological integration is facilitated if the design scope, process and notation of individual methods are well defined. Such characteristics are found in a class of Software Engineering methods commonly referred to as structured analysis and design methods. Unfortunately, the same are not currently to be found for human factors since its methods are generally unstructured and focus only on later design stages. 1 Thus, a pre-requisite for integration is the derivation of a reasonably complete and structured human factors method. Since well developed Software Engineering methods already exist, it would be appropriate (for the purposes of methodological integration) to structure human factors methods around specific structured analysis and design methods. The undertaking is exemplified by the present research for the Jackson System Development method. In other words, the scope of the thesis comprises the derivation, test and integration of a structured human factors method with the Jackson System Development method. In conclusion, the research contributes to the Human Factors discipline in two respects. Firstly, it informs the research community on how similar work with other structured analysis and design methods may be set up. Secondly, it offers designers an extended Jackson System Development method that facilitates the incorporation of human factors during system development