Problem Solving
Artificial Intelligence Research at Carnegie-Mellon University
AI research at CMU is closely integrated with other activities in the Computer Science Department, and to a major degree with ongoing research in the Psychology Department. Although there are over 50 faculty, staff and graduate students involved in various aspects of AI research, there is no administratively (or physically) separate AI laboratory. To underscore the interdisciplinary nature of our AI research, a significant fraction of the projects listed below are joint ventures between computer science and psychology.
Problem Solving Tactics
Finally, abstraction can be extended to involve multiple complexity. In particular, one of the most costly behaviors levels, leading to a hierarchy of plans, each serving as a of the basic problem solving strategies is their inefficiency skeleton for the problem solving process at the next level in dealing with goal descriptions that include conjunctions. of detail. The search process at each level of detail can Because there is usually no good reason for the problem thus be reduced to a sequence of relatively simple solver to prefer to attack one conjunct before another, an subproblems of achieving the preconditions of the next incorrect ordering will often be chosen. This can lead to step in the skeleton plan from an initial state in which the an extensive search for a sequence of actions to try to previous step in the skeleton plan has just been achieved.
Generalizations based on explanations
GENERALIZATIONS BASED ON EXPLANATIONS Gerald DeJong Coordinated Science Laboratory University of Illinois 1101 West Springfield Avenue Urbana, IL 61801 This paper describes a new project at the University of Illinois in computer learning. The phenomenon under study is a kind of "insight learning" of procedural schemata. The system described here is designed to grasp some principle underlying a natural language input. Once acquired, the schema serves the same purpose as the other schemata in the system: it aids in processing future natural language inputs. The neutral term "schema" rather than "frame" (Minsky (1975), Charniak (1976)) or "script" (Schank A Abelson (1977)) is used to refer to knowledge chunks because a frame (which is used to describe static objects as well as progressions of world situations) is too general a notion, and the notion behind a script is-too specific.
Associative search network: A reinforcement learning associative memory
Barto, A. G. | Sutton, R. S. | Brouwer, P. S.
An associative memory system is presented which does not require a "teacher" to provide the desired associations. For each input key it conducts a search for the output pattern which optimizes an external payoff or reinforcement signal. The associative search network (ASN) combines pattern recognition and function optimization capabilities in a simple and effective way. We define the associative search problem, discuss conditions under which the associative search network is capable of solving it, and present results from computer simulations. The synthesis of sensory-motor control surfaces is discussed as an example of the associative search problem.
Optimal Search Strategies for Speech Understanding
Specifically, it is concerned with control strategies governing the formation and refinement of partial hypotheses about the identity of an utterance that can guarantee the discovery of the best possible interpretation. We assume a system that contains the following components: a) A Lexical Retrieval component that can find the k best matching words in any region of an utterance subject to certain constraints and can be recalled to continue enumerating word matches in decreasing order of goodness (where possible constraints include anchoring the left or right end of the word to particular points in the utterance or to particular adjacent word matches).
Planning and Meta-Planning
The selection of what to do next is often the hardest part of resource-limited problem solving. In planning problems, there are typically many goals to be achieved in some order. The goals interact with each other in ways which depend both on the order in which they are achieved and on the particular operators which are used to achieve them. A planning program needs to keep its options open because decisions about one part of a plan are likely to have consequences for another part. This paper describes an approach to planning which integrates and extends two strategies termed the least-commitment and the heuristic strategies.
Utterance and Objective: Issues in Natural Language Communication
Two premises, reflected in the title, underlie the perspective from which I will consider research in natural language processing in this article. First, progress on building computer systems that process natural languages in any meaningful sense (i.e., systems that interact reasonably with people in natural language) requires considering language as part of a larger communicative situation. Second, as the phrase “utterance and objective” suggests, regarding language as communication requires consideration of what is said literally, what is intended, and the relationship between the two.
The Stanford Heuristic Programming Project: Goals and Activities
Buchanan, Bruce G., Feigenbaum, Edward A.
The Heuristic Programming Project of the Stanford University Computer Science Department is a laboratory of about fifty people whose main goals are to model the nature of scientific reasoning processes in various types of scientific problems and various areas of science and medicine; and to construct expert systems — programs that achieve high levels of performance on tasks that normally require significant human expertise for their solution.
The contract net protocol: High-level communication and control in a distributed problem solver
"The contract net protocol has been developed to specify problem-solving communication and control for nodes in a distributed problem solver. Task distribution is affected by a negotiation process, a discussion carried on between nodes with tasks to be executed and nodes that may be able to execute those tasks. We present the specification of the protocol and demonstrate its use in the solution of a problem in distributed sensing. The utility of negotiation as an interaction mechanism is discussed. It can be used to achieve different goals, such as distributing control and data to avoid bottlenecks and enabling a finer degree of control in making resource allocation and focus decisions than is possible with traditional mechanisms." IEEE Transactions on Computers C-29(12):1104-1113. PDF: http://www.reidgsmith.com/The_Contract_Net_Protocol_Dec-1980.pdf.