摘要:

McAllester'sconspiracy numbersalgorithm is an exciting new approach to minimax search that builds trees to variable depth without application‐dependent knowledge. The likelihood of the root taking on a value is expressed by its conspiracy number: the minimum number of leaf nodes that must change their value to cause the root to change to that value. This paper describes experiences with the algorithm, using both random and application‐generated trees. Experiments suggest that more emphasis on breadth, rather than depth, can lead to significant performance improvements. New enhancements to the algorithm are capable of solving 41% more problems than McAllester's original propo

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1990.tb00125.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A hierarchical planning system achieves efficiency by planning with the most important conditions first, and considering details later in the planning process. Few attempts have been made to formalize the structure of the planning knowledge for hierarchical planning. For a given domain, there is usually more than one way to define its planning knowledge. Some of the definitions can lead to efficient planning, while others may not. In this paper, we provide a set of restrictions which defines the relationships between a non‐primitive action and its set of subactions. When satisfied, these restrictions guarantee improved efficiency for hierarchical planning. One important feature of these restrictions is that they are syntactic and therefore do not depend on the particular structure of any plan. Along with these restrictions, we also provide algorithms for preprocessing the planning knowledge of a hierarchical planner. When used during planning, the preprocessed operator hierarchies can enable a planner to significantly reduce its search spac

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1990.tb00126.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Human discourse is fraught with rhetorical devices such as contradictions, illustrations, and analogies. These rhetorical devices carry important information which a listener uses to speed up the comprehension process. In this paper, we present a taxonomy of rhetorical devices commonly used in tutoring environment, and model the meaning of a class of rhetorical devices in terms of their anticipated effect on a listener's knowledge. These predictions are then used in planning computer‐generated discourse. As a testbed for our ideas, a system called WISHFUL is being implemented to generate commentaries in the domain of high‐school algebra within the framework of an intelligent tutoring sys

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1990.tb00127.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A basic agent has been constructed which integrates limited natural language understanding and generation, temporal planning and reasoning, plan execution, simulated symbolic perception, episodic memory, and some general world knowledge. The agent is cast as a robot submarine operating in a two‐dimensional simulated “Seaworld” about which it has only partial knowledge. It can communicate with people in a vocabulary of about 800 common English words using a medium coverage grammar. The agent maintains an episodic memory of events in its life and has a limited ability to reflect on those events. A person can make statements to the agent, ask it questions, and give it commands. In response to commands, a temporal task planner is invoked to synthesize a plan, which is then executed at an appropriate future time. A large variety of temporal references in natural language are interpreted with respect to agent time. The agent can form and retain compound future plans, and replan in response to new information or new commands. Natural language verbs are represented in a state transition semantics for compatibility with the planner. The agent is able to give terse answers to questions about its past experiences, present activities and perceptions, future intentions, and general knowledge. No other artificial intelligence artifact with this range of capabilities has previously been constr

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1990.tb00128.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY