This thesis reports the research which led to the development of the P.R .O. Expert System Shell. The P.R.O . System is primarily, though not exclusively , designed for use in ecological domains. In the light of two specific expert systems, The RCS (River Conservation Status) and the Aquaculture Systems, which were developed as part of this research, a number of areas of importance have been identified. The most significant of these is the need to handle uncertainty effectively. The style of knowledge representation to be implemented also plays an important role. After consulting the relevant literature and the available microcomputer expert system shells, a number of ideas have been included in the P.R.O. System. The P.R.O . System is a backward chaining, production system based expert system shell. It embodies a simple but effective method of handling uncertainty. An important feature of this method is that it takes cognizance of the different relative importances of the conditions which need to be satisfied before a conclusion can be reached. The knowledge base consists of more than rules and questions. It also contains meta-knowledge, which is used by the inference engine. The P.R.O. System has been designed to be of practical use. Its strongest recommendations are therefore, that the two non-trivial systems which have been implemented in it, have been accepted by the experts and their peers as systems which produce good, accurate answers . / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

Ever since MYCIN introduced the idea of computer-based explanations to the artificial intelligence community, it has come to be taken for granted that all knowledge-based systems (KBS) need to provide explanations. While this widely-held belief has led to much research on the generation and implementation of various kinds of explanations, there has however been no theoretical or empirical evidence to suggest that 1) explanations are used by users of KBS, and 2) the use of explanations benefits KBS users in some way. In view of this situation, this study investigates the use of explanations that are provided by a knowledge-based system, from the perspective of understanding both the specific factors that influence it, as well as its effects. The first part of this dissertation proposes a cognitive learning theory based model that both clarifies the reasons as to why KBS need to provide explanations and serves as the basis for conceptualizing the provision of KBS explanations. Using the concepts of the feed forward and feedback operators of cognitive learning it develops strategies for providing KBS explanations and uses them to classify the various types of explanations found in current KBS applications. The roles of feedforward and feedback explanations within the context of the theory of cognitive skill acquisition and a model of expert judgment are also analyzed. These, together with past studies of KBS explanations, suggest that user expertise, the types of explanations provided, and the level of user agreement are significant factors that influence the explanation seeking behavior of users. The dissertation also explores the effects of the use of KBS explanations in judgmental decision making situations supported by a KBS. It identifies and considers four distinct categories of potential effects of the use of explanations --- learning effects, perceived effects, behavioral effects, and effects on judgmental decision making. The second part of the dissertation empirically evaluates the explanation provision strategies in a laboratory experiment in which 80 novice and expert subjects used a KBS for financial analysis to make judgments under conditions of uncertainty. The experiment was designed specifically to investigate the following fundamental research questions: 1) To what extent are the various kinds of explanations used? 2)How does user expertise, the feedforward and feedback provision of explanations, and the level of user agreement influence the amount and the types of explanations that are used? and 3) Does the use of explanations affect the accuracy of judgmental decision-making and user perceptions of usefulness? Some of the major results relating to the determinants of the use of KBS explanations include:1) user expertise is not a determinant of the proportion of explanations used but influences the types of explanations that are used, 2) explanation provision strategy is a critical determinant of the use of KBS explanations with feedback explanations being used significantly more than feedforward explanations, and 3)the three types of explanations are used in different proportions with the Why and How explanations being used significantly more than the Strategic explanations. It was also found that the level of user agreement with the KBS had an "inverted-U" shaped relationship with the use of explanations. The least number of explanations are used when the level of user agreement is either very high or very low. The major results relating to the effects of the use of explanations include the following: 1) the increased use of feedback explanations improves the accuracy of judgmental decision-making but has no effect on user perceptions of usefulness, 2) the increased use of feedforward explanations while having no impact on the accuracy of judgments is positively correlated with user perceptions of usefulness, 3) the use of the Why explanation as feedback improves the accuracy of judgmental decision-making. As well, there was also evidence that the use of the KBS benefited both experts and novices. Considering that an understanding of the determinants and effects of the use of KBS explanations is a critical prerequisite for the design of KBS explanations, these and other findings of the study contribute both towards the development of a theoretical basis for the provision of KBS explanations, as well as the practical design of such explanation facilities. / Business, Sauder School of / Management Information Systems, Division of / Graduate

Bibliography: pages 227-236. / This thesis concentrates on several important issues in expert system research, namely - representation of knowledge - control of reasoning - implementation of non-monotonic logics via truth maintenance systems. There are three parts to this thesis. PART1 covers the background research in the above mentioned topics. PART2 discusses the WISE system and the way in which research from PART1 was applied to the development of the WISE shell. PART3 considers the features of other expert system shells.

M.Comm. / The present study comprises an investigation into and a discussion on the development of expert systems. The theme of the study is of topical interest, since expert systems form an important part of the latest developments in the domain of computer technology. At present, a general deficiency is being experienced in the computer industry in respect of a structured development methodology, and specifically in respect of cost-effective expert systems. The reasons for and causes of the said deficiency, as well as the different ways and means in which possibly to supply this deficiency, represent the issue to be investigated in the present study. Owing to the above-mentioned deficiency in respect of information system methodologies, certain applications and principles have been used throughout the study in a bid to illustrate the differences and similarities between the developmental aspects of certain conventional systems, compared to the same developmental aspects of expert systems. The importance of the various stages of development that the expert system undergo also comes under consideration, together with the development applications and resources, the criteria for cost effectiveness, knowledge engineering and information security. Hereafter, the Sphere Model, based on the introductory chapters, is presented as the solution to the problem posed in the study. This model can, for the entire life cycle of an expert system, be applied in respect of the analysis of the cost effectiveness of such system, and can, at the same time, assist in gathering vital information on the production of subsequent highquality and cost-effective expert systems.

The Refiner series of intelligent systems are used to create non-overlapping category descriptions from a set of cases which have been assigned to categories by an expert.  The systems generalise values for descriptors (fields) for each of the categories to create category descriptions, and suggest to the user various means by which any inconsistencies can be removed. In this thesis we define a new expert system, AKT-R4, which is the fourth iteration of the Refiner series.  Unlike the previous Refiner systems, the focus on AKT-R4 is classification rather than the creation of unambiguous category descriptions. The AKT-R4 system is based on a case-based algorithm focussed on performing a classification task, in particular medical (differential) diagnosis (a classic classification task); AKT-R4 is aimed primarily at medical students and junior doctors (i.e. novice diagnosticians) although it is not domain specific. The AKT-R4 algorithm incorporates concepts from case-based reasoning, hypothetico-deductive reasoning and illness scripts, and performs diagnosis by means of a new concept known as the diagnosis web, which is an expansion of the illness script concept.  This system supports the novice user as he/she develops and navigates through a medical knowledge web and requires no additional knowledge acquisition beyond the specification of a set of cases which the system uses to build a model of the domain. Medical diagnosis is difficult to perform and difficult to teach as it requires a large volume of information of various kinds, and an appreciation of the differential diagnosis process.  As such, an additional benefit of the AKT-R4 system is that it can be used to tutor diagnosis. A preliminary evaluation of the system has been performed and some useful feedback has been received.

Thesis (Ed. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 99-105).

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Abstract. Includes bibliographical references (leaves 40-45). Also available via the Internet.

Thesis (M.S.)--Ohio University, June, 1989. / Title from PDF t.p.

Thesis (M.S.)--Rochester Institute of Technology, 1985. / Typescript. Includes bibliographical references (leaves 74-75).

Thesis (M.B.A.)--University of Hong Kong, 1996. / Includes bibliographical references.