摘要:

This paper describes an attempt to develop a statistical expert system (FILTEX) as an intelligent aid for time-series filter design. To this end the knowledge of the filter design strategy is represented in Prolog and coupled with numerical routines of a general purpose signal processing package. This knowledge-based system is conceived as a set of independent knowledge sources integrated into a system by a blackboard mechanism which embodies overall control of the filter design process. Modularity and flexibility of knowledge representation in such a framework preserve usability of the evolving system during its development from the original numerical package to an expert system for filter design. This approach seems to be more flexible than the use of shells and less time consuming than building from scratch. A novel method for incorporating classical statistical information into an uncertainty management mechanism is presented. Experimental results confirm the feasibility of the approach and set directions for further research.

ISSN:0266-4763    

DOI:10.1080/02664769100000011

出版商:Carfax Publishing Company    

年代:1991

数据来源: Taylor

摘要:

Causal probabilistic models have been suggested for representing diagnostic knowledge in expert systems. This paper describes the theoretical basis for and the implementation of an expert system based on causal probabilistic networks. The system includes model search for building the knowledge base, a shell for making the knowledge base available for users in consultation sessions, and a user interface. The system contains facilities for storing knowledge and propagating new knowledge, and mechanisms for building the knowledge base by semi-automated analysis of a large sparse contingency table. The contingency table contains data acquired for patients in the same diagnostic category as the intended application area of the expert system. The knowledge base of the expert system is created by combining expert knowledge and a statistical model search in a model conversion scheme based on a theory developed by Lauritzen & Spiegelhalter and using exact tests as suggested by Kreiner. The system is implemented on a PC and has been used to simulate the diagnostic value of additional clinical information for coronary artery disease patients under consideration for being referred to coronary arteriography.

ISSN:0266-4763    

DOI:10.1080/02664769100000012

出版商:Carfax Publishing Company    

年代:1991

数据来源: Taylor

摘要:

This paper describes methods for extracting belief functions from data and incorporating expert opinions. The techniques are applied to a medical domain involving the diagnosis of diferent types of liver diseases. This is a domain in which experts are poor at predicting precise (singleton) outcomes. The methodology developed is shown to perform considerably better than the experts alone. Several methods by which to find belief functions from data are compared, and some methods proposed here are shown to outperform a suggestion by Shafer. The system has been fully implemented on a SEQUENT parallel machine and has a user interface which is simple to use and allows for changes and questions.

ISSN:0266-4763    

DOI:10.1080/02664769100000013

出版商:Carfax Publishing Company    

年代:1991

数据来源: Taylor

摘要:

A prototype of a statistical consultation system was developed with an emerging methodology for the development of knowledge-based systems. Although the Statcons-1 prototype has a working problem solver and an advanced direct manipulation interface, it appears that the intended users cannot work with the system. This problem is due to a lacuna in the development of Statcons-1. Therefore the methodology was extended to support the analysis of co-operation between user and system. This analysis results in a model of co-operation that can be empirically tested in mock-up experiments with future users. This paper applies the analysis of co-operation to the StatCons domain. Mock-up experiments suggest that a redesigned system would be satisfactory.

ISSN:0266-4763    

DOI:10.1080/02664769100000014

出版商:Carfax Publishing Company    

年代:1991

数据来源: Taylor

摘要:

In recent years, several expert systems have been developed for practical applications in applied statistical methodologies. Existing expert systems in statistics have explored several areas, e.g. the determination of appropriate statistical tests, regression analysis, and determination of the ‘best’ experimental design for industrial screening experiments. We present here the DESIGN EXPERT which is a prototype expert system for the design of complex statistical experiments. It is intended for scientific investigators and statisticians who must design and analyze complex experiments, e.g. multilevel medical experiments with nested factors, repeated measures, and both fixed and random eflects. This system is ‘expert’ in the sense that it is capable of the following:(i) recognize specific types of complex experimental designs, based on the application of inference rules to non-technical information supplied by the user; (ii) encode the obtained and inferred information in a flexible general-purpose internal representation, for use by other program modules; (iii) generate analysis of variance tables for the recognized design and an appropriate BMDP runfile for data analysis, using the encoded information. DESIGN EXPERT is capable of recognizing randomized block designs, including lattice designs within embedded Latin squares, cross-over designs, split plots, nesting, repeated measures and covariates. It is written in an experimental programming language developed specifically for research in artificial intelligence.

ISSN:0266-4763    

DOI:10.1080/02664769100000015

出版商:Carfax Publishing Company    

年代:1991

数据来源: Taylor