Reasoning about motion is an important part of our commonsense knowledge, involving fluent spatial reasoning. This work studies the qualitative and geometric knowledge required to reason in a world that consists of balls moving through space constrained by collisions with…

A fundamental problem in artificial intelligence is obtaining coherent behavior in rule-based problem solving systems. A good quantitative measure of coherence is time behavior; a system that never, in retrospect, applied a rule needlessly is certainly coherent; a system suffering…

How much information about the shape of an object can be inferred from its image? In particular, can the shape of an object be reconstructed by measuring the light it reflects from points on its surface? These questions were raised…

The actor message-passing model of concurrent computation has inspired new ideas in the areas of knowledge-based systems, programming languages and their semantics, and computer systems architecture. The model itself grew out of computer languages such as Planner, Smalltalk, and Simula,…

The work reported here lies in the area of overlap between artificial intelligence software engineering. As research in artificial intelligence, it is a step towards a model of problem solving in the domain of programming. In particular, this work focuses…

This thesis presents an analysis of a learning situation of positive and negative integers. It is considered as a case study within the more general context of the development of school learning analysis tools based on cognitive psychology. An analysis…

This thesis contains eight chapters. The first deals with Gide's knowledge of English, the second with his ideas on translation. The remaining six examine his versions of the following: Gitanjali by Rabindranath Tagore, parts of Leaves of Grass by Walt…

A satisfactory definition of the imagination has proved elusive in Western philosophy. Two contemporary French thinkers, Gilbert Durand and Paul Ricoeur, are concerned with establishing a fundamental philosophy of imagination. For Durand the imagination is the source of symbolic mediations…

A system for visual recognition is described, with implications for the general problem of representation of knowledge to assist control. The immediate objective is a computer system that will recognize objects in a visual scene, specifically hammers. The computer receives…

This report develops a conceptual framework in which to talk about mathematical knowledge. There are several broad categories of mathematical knowledge: results which contain the traditional logical aspects of mathematics; examples which contain illustrative material; and concepts which include formal…