摘要:

Level of service (LOS) is a qualitative measure of traffic flow from the users' perspectives. This paper presents a new methodology to find LOS of urban roads by taking users' perceptions and analyzing them through fuzzy set theory. Speed, volume and acceleration noise (defined as the standard deviation of accelerations) are taken as the evaluating criteria. The six categories of LOS A to F of the Highway Capacity Manual are assigned linguistic terms. The users have been divided into two age groups. Their perceptions, recorded through primary surveys, have been used to establish membership functions for different fuzzy sets and to arrive at importance factors assigned to them. Four important corridors of movement in the Metropolitan City of Madras formed the backdrop of the study.

ISSN:0263-0257    

DOI:10.1080/02630259608970213

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper addresses the optimum design of axially loaded non-prismatic steel columns, in which the objective is to minimize their volume under a given load by changing their shape, and assuming that are subject to buckling and strength constraints. We use a genetic algorithm (GA) to move through the search space of possible column designs, and choose the best one. Several issues arise when using the GA, such as how to decide which is the most appropriate representation scheme and how to fine tune its parameters. Both floating point and binary representation (with and without Gray coding) were used and compared to a more traditional optimization technique based on the generalized reduced gradient method. Our results show that the floating point representation provides the best solutions overall, reducing the volume of the column up to 30% in some cases.

ISSN:0263-0257    

DOI:10.1080/02630259608970214

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper describes the testing stage of the knowledge base of the expert system EXACT (EXpert system of Actuated control for Traffic at isolated intersections). In Tests by two parties (our expert and external experts), more than eighty percent agreement was found between EXACT's solutions and the two parties’ solutions. EXACT was developed to assist traffic engineers in selecting the appropriate type of traffic-actuated controller and its associated features, the type of detector and its configuration, and time settings at a particular intersection. The development of EXACT, including the identification of variables, shell selection, knowledge acquisition, knowledge representation, and knowledgebase development, was presented in earlier papers.

ISSN:0263-0257    

DOI:10.1080/02630259608970215

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259608970216

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259608970217

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor