The paper exhibits experience, and that of others using QA2 and QA3, solutions to these problems obtained by QA3, a one of the first difficulties encountered is the computer program based on these theorem-proving representation of problems, especially statetransformation methods.

"Almost all the basic methods used by

ABSTRACT Prospector is a computer consultant system intended to aid geologists in evaluating the favorability of an exploration site or region for occurrences of ore deposits of particular types. Knowledge about a particular type of ore deposit is encoded in a computational model representing observable geological features and the relative significance thereof. We describe the form of models in Prospector, focussing on inference networks of geological assertions and the Bayesian propagation formalism used to represent the judgmental reasoning process of the economic geologist who serves as model designer. Following the initial design of a model, simple performance evaluation techniques are used to assess the extent to which the performance of the model reflects faithfully the intent of the model designer. These results identify specific portions of the model that might benefit from "fine tuning", and establish priorities for such revisions. This description of the Prospector system and the model design process serves to illustrate the process of transferring human expertise about a subjective domain into a mechanical realization. I. INTRODUCTION In an increasingly complex and specialized world, human expertise about diverse subjects spanning scientific, economic, social, and political issues plays an increasingly important role in the functioning of all kinds of organizations. Although computers have become indispensable tools in many endeavors, we continue to rely heavily on the human expert's ability to identify and synthesize diverse factors, to form judgments, evaluate alternatives, and make decisions -- in sum, to apply his or her years of experience to the problem at hand. This is especially valid with regard to domains that are not easily amenable to precise scientific formulations, i.e., to domains in which experience and subjective judgment plays a major role.

In this section, I propose another, quite different view about the nature To choose their actions, reasoning programs must be able to make assumptions and subsequently of reasoning. I incorporate some new concepts into this view, and the combination revise their beliefs when discoveries contradict these assumptions. The Truth Maintenance System overcomes the problems exhibited by the conventional view.

TEntEsuis is a program designed to provide assistance on the task of building knowledge-based results and motivations for its actions.

Another concern has been to exploit (d) detection of metabolic disorders of genetic, developmental, toxic or infectious the AI methodology to understand better some fundamental questions in the origins by identification of organic constituents excreted in abnormal quantities philosophy of science, for example the processes by which explanatory hypotheses in human body fluids.

In this paper we present a new algorithm for searching trees. The algorithm, which we have named For this reason, the search is usually limited in some way (e.g., number of nodes B*, finds a proof that an arc at the root of a search tree is better than any other. It does this by to be expanded, or maximum depth to which it may go).

Human programmers seem to know a lot about programming. This suggests a way to try to build here was designed to shed some light on questions like these.

R. L. GREGORY, Psychological Laboratory, Cambridge Discussion on paper 5 683 6 Some questions concerning the explanation of learning 691 in animals MR. A. J. WATS01,4 Psychological Laboratory, Cambridge Discussion on paper 6 721 7 Information, redundancy and decay of the memory trace 729 DR. Y. BAR-HILLEL, The Hebrew University, Jerusalem Discussion on paper 2 801 3 To what extent can administration be mechanized?

APPENDIX I Attendance List *An asterisk indicates either that the person was a part--time deputy for a delegate, or that their attendance was restricted to particular Sessions by accomodation difficulties.