The problem of producing sentences of a transformational grammar by using a random generator to create phrase structure trees for input to the lexical insertion and transformational phases is discussed. A purely random generator will produce base trees which will be blocked by the transformations, and which are frequently too long to be of practical interest. A solution is offered in the form of a computer program which allows the user to constrain and direct the generation by the simple but powerful device of restricted subtrees. The program is a directed random generator which accepts as input a subtree with restrictions and produces around it a tree which satisfies the restrictions and is ready for the next phase of the grammar. The underlying linguistic model is that of Noam Chomsky, as presented in Aspects of the Theory of Syntax.

A question-answering system. Tech. Note 15, AI Group, Stanford Research Institute, Menlo Park, Calif.

Science 166:178-192

This is a reprint of a chapter that first appeared in 1968 in a collection of papers on operations research [1]. The chapter was written to survey the progress in heuristic processes since an earlier 1968 paper on the same topic [2]. In the current collection, it serves as something of a historical introduction to the SOAR system, which occupied Newell and his students for many years. Even though SOAR did not exist at the time this chapter was written, one finds some of the threads that are later to be drawn together into the construction of SOAR. Newell explores so-called weak methods, which trade power for general applicability.

In Walker, D. E. & Norton, L. N. (eds. ), IJCAI 1969: INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, May 7-9, 1969 Washington, D. C., pp. 241-252

A program was writte n to solve calculus word problems. The program, CARPS (CAlculus Rate Problem Solver), is restricte d to rate problems. The overall plan of the program is simila r to Bobrow's STUDENT, the primary difference being the introductio n of "structures " as the internal model in CARPS. Structures are stored internally as trees, each structure holding the information gathered about one object.In Walker, D. E. & Norton, L. N. (eds. ), IJCAI 1969: INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, May 7-9, 1969 Washington, D. C., pp. 241-252

In Walker, D. E. & Norton, L. N. (eds. ), IJCAI 1969: INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, May 7-9, 1969 Washington, D. C., pp. 219-39.

In IJCAI 1969: INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, May 7-9, 1969 Washington, D. C.

PLANNER is a language for proving theorems and manipulating models in a robot. The language is built out of a number of problem solving primitives together with a hierarchical control structure. Statements can be asserted and perhaps later withdrawn as the state of the world changes. Conclusions can be drawn from these various changes in state. Goals can be established and dismissed when they are satisfied . The deductive system of PLANNER is subordinate to the hierarchical control structure in order to make the language efficient . The use of a general purpose matching language makes the deductive system more powerful. In IJCAI-69, pp. 295-€“301.

This paper shows how a question -answering system can be constructed using first -order logic as its language and a resolution -type theorem -prover as its deductive mechanism. A working computer -program, Q A3, based on these ideas is described. The performance of the program compares favorably with several other general question -answering systems.