DecisionSupport Systems for the Water Industry: An Object-Oriented Approach

ReportNo WSAA 74

April 1994




Thisreport outlines the development of MOSES, a Methodology for Object-orientedSoftware Engineering of Systems, which was initially developed in order toconstruct a decision support system to aid in a wastewater resources managementand planning problem. The report also develops a design for the decisionsupport system which provides a case-study evaluation of the methodology.


Theresearch methodology essentially involved theory construction and case studyevaluation. The research was undertaken in three parts. Part A was theidentification of a problem in water resources planning leading to a proposedsolution that involved the development of a decision support system and anumber of process models of a wastewater treatment plant using anobject-oriented approach. Part B was the development of an object-orientedanalysis and design methodology, including the specification of the object-modelsupported, the notation and documentation supported, the life-cycle of anobject-oriented development and the process of the methodology. Part C was anevaluation of the methodology and the construction of an object-oriented designfor a decision support system for wastewater planning called ECWAT.


Thereare two major contributions of the research: a new object-oriented methodology;and the development of ECWAT. The results of the research into object-orientedmethodologies includes a number of new features in the area of theobject-model, the notation and the process. The object-model is an integrationof semantic modelling and object-oriented programming language models; it usesthe “software by contracting” metaphor for specifying behaviour; and it separatesthe inheritance and generalisation hierarchies during the design process. Thenotation is one of the most complete and consistent yet presented in theliterature while the process is a detailed description of ten major activitiesnecessary to construct an object-model. The research also presents a newobject-oriented life-cycle model, called the fountain model.


Evaluationof the methodology concluded that it was strong as a technical methodology butwas less comprehensive in the areas of management and design metrics which wereidentified as an important areas for further work.


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