摘要:

This paper describes the development of the knowledge base of the expert system EXACT (EXpert system of Actuated control for Traffic at isolated intersections). 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 knowledge-base of EXACT consists of three primary elements: frames, parameters, and rules. These elements are activated by a back-word chaining mechanism during a consultation. The ability to explain its reasoning process to the user is one important feature of EXACT. Moreover, EXACT's knowledge-base has the capability of interfacing with graphics program in order to enhance the understandability of the system. A full description of the knowledge-base development of EXACT as well as its graphics interface are presented below.

ISSN:0263-0257    

DOI:10.1080/02630259308970117

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This study presents the design of a database system that allows storing and manipulating pavement condition data in a systematic manner. The principal design process consists of generating a relational database and developing application interfaces. The database design follows defined functional specifications and places emphasis on the structuring of relation scheme and the manipulation of data. Furthermore, issues of data validation and data conversion are addressed. The developed database is utilized for the design of forms, menus, reports, and programmatic interfaces to facilitate condition evaluation of pavement structures. The user interface and other important design aspects of the system are evaluated and discussed. It is concluded that the developed database system has the capabilities of integrating various levels of data applications.

ISSN:0263-0257    

DOI:10.1080/02630259308970118

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper proposes a new mathematical programming method—grey fuzzy linear programming (GFLP)—as a means for optimization analysis under uncertainty. The method improves upon previous grey linear programming (GLP) and flexible fuzzy linear programming (FLP) methods by allowing uncertainty in both the model coefficients and stipulations to be effectively communicated into the optimization process, and thus provide more satisfactory solutions for an optimization problem under uncertainty. Compared with the ordinary GLP method, grey solutions with smaller variations are provided, which may be useful when model inputs are very uncertain. Compared with existing flexible FLP methods, more uncertain information is incorporated within the GFLP model, and the tolerance interval of the objective function value can be determined quantitatively.

ISSN:0263-0257    

DOI:10.1080/02630259308970119

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Structural design methods that employ optimization have traditionally followed one of two approaches: optimal elastic design which considers constraints on elastic stresses; and, optimal plastic design, involving ultimate load constraints. This study addresses elastic and plastic design, incorporated into an iterative scheme for checking both linear elastic stresses and plastic collapse load factors. Structural optimization of steel frames is achieved through material reallocation, which is governed by a generalized stress parameter in those cases where elastic design controls, and by a reduced cost vector from a linear program when the plastic collapse load factor controls. Regression analysis techniques among member properties are employed to reduce the number of independent design variables and to incorporate buckling and axial toad effects for the elastic design. The linear programming optimization procedure is implemented in a computer system developed for the minimum-weight design of steel frames. Our model is applied to one story-one bay, two story-two bay, and three story-five bay frames.

ISSN:0263-0257    

DOI:10.1080/02630259308970120

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259308970121

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor