Problem-Solving under Insu cient Resources

This paper discusses the problem of resources-limited information processing. After a review of relevant approaches in several elds, a new approach, controlled concurrency, is described and analyzed. This method is proposed for adaptive systems working under insu cient knowledge and resources. According to this method, a problemsolving activity consists of a sequence of steps which behaves like an anytime algorithm | it is interruptible, and the quality of the result is improved incrementally. The system carries out many such activities in parallel, distributes its resources among the them in a time-sharing manner, and dynamically adjusts the distribution according to the feedback of each step. The step sequence for a given problem is formed at run time, according to the system's knowledge structure, which is also dynamically formed and adjusted. Finally, this approach is compared with other approaches, and several of its properties and implications are discussed. In a computer system, all problem-solving activities cost computational resources, mainly processor time and memory space. Because these two types of resource can often be substituted by each other, this paper focuses on the management of the time resource. The paper begins by a review of the di erent assumptions about time resource made in various elds for di erent purposes. Then, a new situation, problem-solving under insufcient resources, is de ned and discussed. A resource-management mechanism, controlled concurrency, is proposed for this situation. After its basic components are introduced, the properties and implications of the mechanism are discussed and compared with those of other approaches.

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