The thesis is focused on analysis of property business and the possibility of using expert engineering methods. The broker is seen as an expert in the field of purchasing and renting of estates. The thesis investigates in details the particular operations of the broker and progressivly analysis the possibilities of the aplication of expert engineering methods.

WATREX is an expert system used to aid in potable water treatment plant design and was developed several years ago by the Water Research Commission. More recently, this system was tested and a number of deficiencies identified. Amongst these deficiencies were the list of possible chemicals that should be additionally included in the system, as well as the prediction of turbidity removal. The objectives of this project were to investigate and improve these deficiencies. This was achieved in two ways. The chemical addition deficiency was improved through the introduction of new chemicals as separate processes and via improved formulation to model the effects of these chemicals using a spreadsheet with automated calculation abilities. Turbidity removal prediction was improved by the mathematical modelling using data obtained from existing water treatment plants throughout South Africa. The results obtained from the chemical addition improvements were compared to those obtained from other models and found to be correct. The modelling of the turbidity removal data resulted in a series of equations that predict turbidity removal based on plant performance and incoming turbidity values, a first of its kind. Though complete, these models have yet to be incorporated into the existing WATREX system. / Prof. J. Haarhoff

M.Sc. / Surgical patients admitted to an intensive care unit, are susceptible to infection by a large number of micro-organisms. Host defence mechanisms are breached by severe injuries or operations, or the use of life-support systems such as ventilators, catheters and endotracheal tubes. These organisms, some of which are resistant to antibiotics, can therefore invade sterile tissue. Although tissue samples from infected sites are sent to a laboratory to be analyzed, treatment of the patient has to commence before the results are known. Intelligent computer systems, of which expert systems are one of the most popular applications, can be utilized to support diagnostic and therapeutical decisions. This thesis describes the development of an expert system that supports clinical decision-making in the diagnosis and treatment of hospital-aquired pneumonia in an intensive care unit. Input data required by the expert system module are extracted from a data base with patient records. The data base and expert system module communicates by means of a program written in a conventional programming language. The system, which is only a prototype, can be extended to include additional expert system modules addressing other infections. Aquiring knowledge to be encoded in the expert system's knowledge base, remains a problem. In this case an existing scoring system that assigns weights to measurements and the outcomes of certain investigations, is used to obtain a score according to which pneumonia can be diagnosed. The infection is subsequently classified as one of several categories, according to existing guidelines. Appropriate therapy is recommended. The system can also consult a file containing sensitivities of bacteria for antibiotics for the unit, in order to facilitate the choice of drugs. The system has been implemented and tested with a few cases.

The rule excluding evidence of opinion is traditionally stated in broad and general terms, subject to a more or less closed list of exemptions. Stephen says that a witness’s opinion is “deemed to be irrelevant”. A witness may depose to the facts which he has observed, but he may not ordinarily state any inferences which he has drawn from those facts, or opinions founded upon facts of which he has no personal knowledge. The general rule is that the evidence of opinion or belief of a witness is irrelevant because it is the function of a court to draw inferences and form its opinion from the facts; the witnesses give evidence as to the facts and the court forms its opinion from those facts. The opinion of an expert is admissible if it is relevant. It will be relevant if the witness’s skill, training or experience enables him materially to assist the court on matters in which the court itself does not usually have the necessary knowledge to decide. Where the topic is such that an ordinary judicial officer could be expected to be able, unassisted, to draw an inference, expert evidence is superfluous. In principle, there is no rule that a witness cannot give his opinion on an issue that the court has to decide ultimately. It is not experts alone who may give their opinions on ultimate issues but, in practice, there is a strong tendency to regard the evidence of lay persons on ultimate issues as constituting prima facie evidence only. If such lay testimony remains unchallenged, it may be of greater significance. It is generally true that relevant evidence is admissible and irrelevant evidence is inadmissible. At this stage the following question may be posed: is the opinion of any witness – whether from an expert or lay person – admissible evidence? Should an opinion be admitted for purposes of persuading the court to rely on it in deciding the issue at hand? The basic answer is that relevance remains the fundamental test for admissibility. Certain issues simply cannot be decided without expert guidance. Expert opinion evidence is therefore readily received on issues relating to ballistics, engineering, chemistry, medicine, accounting and psychiatry, to mention only a few examples. The problem which arises is this: what is the best way of cross-examining the expert witness? Although the concept of skilful cross-examination conjures up the image of the crossexaminer destroying the expert witness in the witness box, total annihilation of expert evidence in court occurs only rarely. In reality, lawyers who are expected to cross-examine experts are often at a disadvantage in that they do not possess sufficient in-depth knowledge of the specific field of expertise to enable them to cross-examine the witness. Despite the expert nature of the evidence, it is suggested that the true basis of crossexamination should not be abandoned when dealing with experts. The effectiveness of crossexamination is enhanced by keeping the number of questions to a minimum as well as opening and concluding with good strong points. At the outset it should be mentioned that there is a distinction between matters of scientific fact and matters of mere opinion. On matters of scientific fact experts seldom differ but within the province of opinion one encounters difficulties. Lengthy cross-examination concerning expert’s theoretical knowledge is usually inefficient and should rarely be attempted. Cross-examination should be directed at pure logic or scientific analysis. The cross-examiner should always have relevant authority with him in court so as to confront the expert with these. The whole effect of the testimony of an expert witness can also be destroyed by putting the witness to test at the trial as to his qualifications, his experience and his ability and discriminations as an expert. A failure to meet this test renders his evidence nugatory.

This thesis explores whether computer-based expert systems can be used in planning and, if so, under what circumstances. Expert systems are computer-based programs that solve problems in a way that mimics the human reasoning process. Expert system reasoning relies upon logic and rules-of-thumb rather than the numerical and mathematical algorithms of most other computer programs. Planning has been interpreted in the professional context of urban and regional planning, rather than the cross-disciplinary fiscal or project management planning often implied in computer literature. To determine expert systems could be useful to planners, the reasons for incompatibility between the nature of planning and conventional computers models of the past are explored. Advantages and disadvantages of expert systems are considered. Expert systems represent substantial improvement in areas where conventional programs are inadequate. Chapters 2 to 5 form the theoretical base of the thesis. Chapter 2 explains the fundamentals of expert system reasoning and how it differs from other computer software. Chapter 3 outlines reasons why this technology might appeal to planners. Chapter 4 introduces some of the disadvantages of expert systems, including technical limitations, ethical and legal issues. Chapter 5 introduces general guidelines to help the reader understand what type of planning tasks might benefit from the use of this new tool. Chapters 6 to 8 consider issues raised in the preceding chapters. Three Canadian systems now at the forefront of expert systems applications to planning are reviewed in chapters 6, 7 and 8 Respectively. The first application, HERMES, is an emergency planning application. It advises emergency response personnel during crises involving hazardous materials. SCREENER is an environmental planning application. It assists environmental officers at Transport Canada to assess simple capital projects for environmental impact statements and screen out more complicated ones for further review. The third application used for illustrative purposes, PLANCHECKER, is a municipal planning example. The system assists plan checkers at City Hall in assessing building plans. The three case-studies satisfy the task suitability guidelines quite well and appear to be successful applications of expert systems to planning. It is still too early to draw definite conclusions, but it is likely the technology will prove useful to planners. Planners should be prepared understand both the potential and limitations of expert systems so they can use the technology wisely. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Expert systems are being developed despite the widely acknowledged problem of acquiring knowledge from experts. This study attempts to understand how knowledge acquisition is conducted in practice by investigating three expert system development projects. The variables examined include the expert, knowledge engineer, problem domain, organizational setting, the knowledge acquisition process, the expert system construction process, and the expert system itself. A case research methodology is adopted and data is collected through observation and taped protocol of knowledge acquisition sessions, post facto interviews with the participants involved, journalistic accounts kept by the subjects, and deliverables produced. Three cases on expert systems built in the domains of law of negligence, telephone line fault diagnostic, and wastewater treatment have been investigated. By juxtaposing the observations drawn from these cases with the findings reported in the literature, this inquiry contributes to the current understanding of the knowledge acquisition process. / Business, Sauder School of / Graduate

The work described in this thesis stems from the idea that expert systems should be able to accurately and appropriately handle uncertain information. The traditional approaches to dealing with uncertainty are discussed and are shown to contain many inadequacies. The Dempster-Shafer, or D-S, theory of evidence is proposed as an appealing theoretical basis for representing uncertain knowledge and for performing inexact reasoning in expert systems. The D-S theory is reviewed in some detail; including its approaches to representing concepts, to representing belief, to combining belief and to performing inference. The D-S implementation approaches pursued by other researchers are described and critiqued. Attempts made early in the thesis research which failed to achieve the important goal of consistency with the D-S theory are also reviewed. Two approaches to implementing D-S theory in a completely consistent manner are discussed in detail. It is shown that the second of these systems, a frame network approach, has led to the development of a fully functional prototype expert system shell called FRO. In this system, concepts are represented using D-S frames of discernment, belief is represented using D-S belief functions, and inference is performed using stored relationships between frames of discernment (forming the frame network) and D-S belief combination rules. System control is accomplished using a discrete rule-based control component and uncertain input and output are performed through an interactive belief interface system called IBIS. Each of these features is reviewed. Finally, a simple but detailed example of an application of a frame network expert system is provided. The FRO system user's documentation is provided in the appendix. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Since MYCIN, explanation has become a fundamental feature of knowledge-based systems (KBS). Among the common deficiencies of KBS explanations, the most acute one is the lack of knowledge. This dissertation research investigates the use of explanations provided with hypertext for increasing the availability and accessibility of domain knowledge. The ultimate objective is to determine the behavioral and cognitive basis of the use of hypertext in providing KBS explanations. Two informationally equivalent KBS were comparatively studied in a laboratory setting: one used hypertext to provide explanations, while the other one used conventional lineartext. The experiment involved 26 experienced professionals, and 29 undergraduate and graduate students specializing in accounting. Subjects used the experimental KBS to work on a realistic problem of financial analysis. Both the process and outcomes of explanation use were assessed. Outcome variables included improvement in decision accuracy, trust in the KBS, and perceived usefulness of explanations. In addition to questionnaires used to measure decision accuracy and perceptions, computer logs were used to capture the number, type, and context of explanation use. Thinkingaloud procedures were used to assess the nature of explanation use. Results indicate that the use of hypertext for providing explanations significantly improved decision accuracy, and influenced users' preference for explanation types, and the number and context of explanation requests. Enhanced accessibility to deep explanations via the use of hypertext significantly increased the number of deep explanations requested by both novices and experts. Verbal protocol analysis shows that the lack of knowledge and means of accessing deep explanations could make it difficult to understand KBS recommendations, and that deep explanations could improve the understandability of KBS advice, especially in cases where unfamiliar domain concepts were involved. In the hypertext group, about 37% of the deep explanations were requested in the context of judgment making, rather than in the abstract. While only about 28% of the deep explanations requested by the lineartext group were the How type, 42% were the How type for the hypertext group. Experts and novices had different preferences for explanation types. Experts requested a much higher percentage of How, and lower percentages of Why and Strategic explanations, than novices. Verbal protocol analysis illustrates that experts and novices used explanations for different purposes. / Business, Sauder School of / Management Information Systems, Division of / Graduate

M.Sc. (Computer science) / Knowledge representation suffers from certain problems, which is not a result of the inadequacies of knowledge representation schemes, but of the way in which they are used and implemented. In the first part of this dissertation we examine the relational model (as used in relational database management systems) and we examine frames (a knowledge representation scheme used in expert systems), as proposed by M. Minsky [MIN75]. We then provide our own definition of frames. In the second part, we examine similarities between the two models (the relational model and our frame model), establishing frames as a superclass of relations. We then define normalization for frames and examine how normalization might solve some of the problems we have identified. We then examine the integration of knowledge-based systems and database management systems and classify our normalization of frames as such an attempt. We conclude by examining the place of normalization within the expert system development life cycle

A trial judge serves as gatekeeper in the courtroom to ensure that only reliable expert witness testimony is presented to the jury. Nevertheless, research shows that while judges take seriously their gatekeeper status, legal professionals in general are unable to identify well conducted research and are unable to define falsifiability, error rates, peer review status, and scientific validity (Gatkowski et al., 2001; Kovera & McAuliff, 2000). However, the abilities to identify quality scientific research and define scientific concepts are critical to preventing “junk” science from entering courtrooms. Research thus far has neglected to address that before selecting expert witnesses, judges and attorneys must first evaluate experts’ CVs rather than their scientific testimony to determine whether legal standards of admissibility have been met. The quality of expert testimony, therefore, largely depends on the ability to evaluate properly experts’ credentials. Theoretical models of decision making suggest that ability/knowledge and motivation are required to process information systematically. Legal professionals (judges and attorneys) were expected to process CVs heuristically when rendering expert witness decisions due to a lack of training in areas of psychology expertise. Legal professionals’ (N = 150) and undergraduate students’ (N = 468) expert witness decisions were examined and compared. Participants were presented with one of two versions of a criminal case calling for the testimony of either a clinical psychology expert or an experimental legal psychology expert. Participants then read one of eight curricula vitae that varied area of expertise (clinical vs. legal psychology), previous expert witness experience (previous experience vs. no previous experience), and scholarly publication record (30 publications vs. no publications) before deciding whether the expert was qualified to testify in the case. Follow-up measures assessed participants’ decision making processes. Legal professionals were not better than college students at rendering quality psychology expert witness admissibility decisions yet they were significantly more confident in their decisions. Legal professionals rated themselves significantly higher than students in ability, knowledge, and motivation to choose an appropriate psychology expert although their expert witness decisions were equally inadequate. Findings suggest that participants relied on heuristics, such as previous expert witness experience, to render decisions.