A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 1993

A knowledge-based expert system "PQExpert" has been developed to help make structured, rational and consistent decisions regarding contractor prequalification. Although there are generally accepted decision parameters for contractor evaluation, each organization, and indeed each project, may attach varying importance to different decision factors. PQExpert can suc cessfully handle this difficulty by the knowledge base updating facility it provides - a salient feature of expert systems. It lets the user define client and project requirements for a particular application. PQExpe1t 's Assessment Module builds a sub model according to user-defined specifications, within the global knowledge incorporated into its knowledge-base in the form of IF-THEN rules. The relevant rules are then updated taking into account the user-defined spec ifications. This knowledge-base updating facility of PQExpert that lets the user define sub model within the global model diversifies its applications to a variety of project and owner types. PQExpert can do more than the conventional way of declaring candidates qualified or disqualified. It allows the user to rank the candidates according to their capabilities in different dimensions. It can rank contractors with respect to experience, financial capability, technical expertise or a combination of these. It offers three different methods to determine the rank order of candidate contractors. These weighting methods vary in complexity from the very simple one-dimensional linear way of adding the candidates' ratings in various parameters to more complex multidimensional weighting methods that take into account various factors. A salient feature of PQExpert is its ability to perform sensitivity analysis that lets the user observe the effect of one or more decision factors on prequalification decision and contractor ranking before finalizing the selection process. Sensitivity analysis together with contractor ranking can be used to prepare long and short lists of contractors. In addition to the conventional help facility, PQExpert offers online Hypertext Docu mentation that lets the user retrieve any part of information in a non-linear fashion during the execution of an application. Combination of conventional help and Hypertext Documentation offers far more user friendly interface than conventional expert systems do. In addition to the online Hypertext Documentation, a separate Hypertext Module has been developed on prequ alification that may be used by young officials seeking information on prequalification. This is a useful traininmg module incorporating the knowledge needed to be versatile in prequalification decision making. A small database has also been developed within the environment of PQExpert to have record of prequalification. It is believed that with the use of PQExpert one can make timely, consistent, structured, and rational decisions without much efforts.