W'e present a formal syntax and semantics for the SNePS Semantic Network P recessing System (Shapiro 1979), based on a \leinongian theory of the intensional objects of thought (Rapaport 198Sa). Such a theory avoids possible worlds and is appropriate t or AI considered as "computational philosophy"-AI as the study of how intelligence is possible-or "computational psychology"- .ql

This language must satisfy minimal criteria, as follows.

Retrospective on lessons learned from the Dendral project."The DENDRAL and Meta-DENDRAL programs are products of a large, interdisciplinary group of Stanford University scientists concerned with many and highly varied aspects of the mechanization of scientific reasoning and the formalization of scientific knowledge for this purpose. An early motivation for our wok was to explore the power of existing Al methods, such as heuristic search, for reasoning in difficult scientific problems. Another concern has been to exploit the AI methodology to understand better some fundamental questions in the philosophy of science, for example the processes by which explanatory hypotheses are discovered or judged adequate. From the start, the project has had an applications dimension. It has sought to develop "expert level" agents to assist in the solution of problems in their discipline that require complex symbolic reasoning. The applications dimension is the focus of this paper."Artificial Intelligence 11 (1-2): 5-24

It is essentially a Horn clause theorem prover augmented with a special inference rule for'dealing with

"Computing can change our ways of thinking about many things, mathematics, biology, engineering, administrative procedures, and many more. But my main concern is that it can change our thinking about ourselves: giving us new models, metaphors, and other thinking tools to aid our efforts to fathom the mysteries of the human mind and heart. The new discipline of Artificial Intelligence is the branch of computing most directly concerned with this revolution. By giving us new, deeper, insights into some of our inner processes, it changes our thinking about ourselves. It therefore changes some of our inner processes, and so changes what we are, like all social, technological and intellectual revolutions." This book, published in 1978 by Harvester Press and Humanities Press, has been out of print for many years, and is now online, produced from a scanned in copy of the original, digitised by OCR software and made available in September 2001. Since then a number of notes and corrections have been added. Atlantic Highlands, NJ: Humanities Press.

For example, lnterlisp permits accessing the control stack at an unusually detailed level.

"The terms adaptation, learning, concept-formation, induction, self-organization, and self-repair have all been used in the context of learning system (LS) research. The research has been conducted within many different scientific communities, however, and these terms have come to have a variety of meanings. It is therefore often difficult to recognize that problems which are described differently may in fact be identical. Learning system models as well are often tuned to the require- ments of a particular discipline and are not suitable for application in related disciplines."In Encyclopedia of Computer Science and Technology, Vol. 11. Dekker

Master skill--operational in the sense-t'hat it can be run on Another form of the'Master skill' aspiration aims at correct'strong mastery' in this sense is attainable for the complete None of the above listed endgames contains anything problematical from a Master's point of view and computer programs Using a vocabulary which is defined in Kmoch's (1959) 'An enemy pawn ahead on the same file is a counterpawn, Some of these relations may be very useful if developed further. For expmple, if a pawn is'overloaded', in that it is pefforming Defence Diagram, see Figure 1). A rule is applied'to a position (in a manner familiar to'forcing tree' that guarantees the achievement of better-goals The'and-or' tree search, carried out by module 1 of the AU Figure 1 The ADD corresponding to the position shown in Figure 1. The Computer Journal ' HOW DIFFICULT IS THE KNKR PROBLEM? Longest variation in Fine before capture of the Knight: 24 moves; longest known variation 27 moves.

This paper is concerned primarily with (1) the procedure by which process-oriented specifications are obtained from goal-oriented requirement specifications and (2) computer-based tools for their construction. It first determines some attributes of a suitable process-oriented specification language, then examines the reasons why specifications would still be difficult to write in such a language. The key to overcoming these difficulties seems to be the careful introduction of informality based on partial, rather than complete, descriptions and the use of a computer-based tool that uses context extensively to complete these descriptions during the process of constructing a well-formed specification. Some results obtained by a running prototype of such a computer-based tool on a few informal example specifications are presented and, finally, some of the techniques used by this phototype system are discussed.

THE REPRESENTATION AND USE OF FOCUS IN A SYSTEM FOR UNDERSTANDING DIALOGS Barbara J. Grosz Artificial Intelligence Center SRI International, Menlo Park, California 94025 ABSTRACT As a dialog progresses the objects and actions that are most relevant to the conversation, and hence in the focus of attention of the dialog participants, change. This paper describes a representation of focus for language understanding systems, emphasizing its use in understanding taskoriented dialogs. The representation highlights that part of the knowledge base relevant at a given point in a dialog. A model of the task is used both to structure the focus representation and to provide an index into potentially relevant concepts in the knowledge base The use of the focus representation to make retrieval of items from the knowledge base more efficient is described. I INTRODUCTION To understand the sentences in a discourse, a computer system, like a person, must have knowledge about the domain of the discourse. However, the knowledge required to understand even simple, reallife domains is so extensive that it will overwhelm a system that does not apply it selectively. This means that the ability to focus on the subset of knowledge relevant to a particular situation is crucial. This paper addresses the problem of focus from the perspective of building a computer system that can participate in a task-oriented dialog. A representation for focus is presented; its use is illustrated by showing how the referents of definite noun phrases are identified. A combination of contextual factors influences the interpretation of an utterance. In fact, what is usually meant by "the context of an utterance" is precisely that set of constraints which together direct attention to the concepts of interest in the discourse in which the utterance occurs. Both the preceding discourse context - - the utterances that have already occurred -- and the situational context -- the environment in which an utterance occurs -- affect the interpretation of the utterance. For a dialog, the situational context includes the physical environment, the social setting, and the relationship between the participants in the dialog. This paper shows how the task and dialog contexts combine to provide a focus on those concepts relevant to the interpretation of utterances in task-oriented dialogs.