摘要:

One approach in addressing reliability aspects of water distribution networks is to require two paths from a source to a demand point. The problem faced in these approaches is to define the paths and to what degree there is, or should be, dependency, i.e., common links in those paths. This study attempts to examine the implications associated with these dependency issues. Using an optimization formulation which includes minimum path constraints, various path requirements ranging from a single path to two distinct, independent paths (to each demand node) are investigated.

ISSN:0263-0257    

DOI:10.1080/02630259008970580

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Coping with the increasing shortage of skilled labour, the demands for higher productivity and quality and the inroads of external competition provides a sufficient argument for an increased level of automation in the civil and construction industry. Elsewhere in manufacturing, automation has been brought about by the adoption of more general purpose machines and robots to replace dedicated, and less flexible, items of equipment. By linking such items together through the use of local area networks and factory wide systems the control of product flow and the rescheduling of work to meet demand has been significantly enhanced. Also a mechatronic approach to the design of integrated systems (combining electronic and mechanical engineering and computer technology) provides a further influence upon the design and adoption of automated systems. While the environment of a civil engineering site is a far more unstructured environment than that of a factory, requiring greater flexibility and adaptability from the equipment deployed, the range of opportunities for the deployment of automated systems is nevertheless significant. Therefore this paper considers the requirements for introducing robotic systems within the civil and construction industries and examines the possibility of introducing a particular item of automated plant, namely a robotic excavator. Site requirements are also considered in relation to the introduction of a range of automation and robotic technologies.

ISSN:0263-0257    

DOI:10.1080/02630259008970581

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Decision making in civil engineering systems necessarily involves imprecise data. Fuzzy linear programming (FLP) has been used to deal with imprecision in parameter definitions. In this paper, it is argued that present methods of FLP can be improved upon by using a new method of fuzzy quadratic programming (FQP) which enables the modelling of independent fuzzy parameters. Several numerical examples are presented and compared with other techniques.

ISSN:0263-0257    

DOI:10.1080/02630259008970582

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In this paper, an angular fuzzy set model is introduced. The model uses an angle to determine a line that represents a linguistic value. Therefore, the membership value is a function of the angle a. This angular fuzzy set model can be applied to fuzzy logic modusponensand modus tollensdeduction techniques. In relation to these techniques, we employ fuzzy logic operations, such as the truth functional modification and inverse truth functional modification. A relatively simple calculation procedure is required to perform these operations. The conventional models that are represented graphically could pose difficulties during the interpretation of the graphs. The angular models, on the other hand, depend only on the angle. They are solved numerically, and therefore are easier to interpret. Illustrations using this model and comparison with conventional models are presented in this paper.

ISSN:0263-0257    

DOI:10.1080/02630259008970583

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This paper presents an information architecture (IA), or a scheme for organizing the categories of required information, to support computer integrated construction. This IA is developed through the analysis of a process model of the functions required to provide an operational facility to the end user during the life of the facility. It has four broad categories of information: product elements (sometimes referred to as product modelling); process control elements (sometimes referred to as project management); feedback elements (sometimes referred to as project control); and finally, constraint elements (typically the codes, economy etc.). The structure for the IA is discussed and detailed definitions of the elements and subelements in each category are presented. These definitions include examples of documents found in use on sites visited. Finally, a strategy for further developing the information architecture is proposed.

ISSN:0263-0257    

DOI:10.1080/02630259008970584

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The use of portfolio theory allows the consideration of correlation between projects and may rationalize the selection of the projects and capital budgeting. Positive coefficient of correlation increases the risk for a portfolio, while negative coefficient decreases the risk. On the other hand, the expected return of a portfolio may increase or decrease due to project correlation. The correlation between projects is due to several casual factors which are of different importance and contribution to project correlation. The importance and the level of contribution of each factor can be estimated based on experience and judgement. Experience and judgement may easily be expressed in semantic measures rather than mathematical terms. Classical portfolio theory fails to incorporate subjective information. The semantic measures can be translated into mathematical values using the fuzzy set theory. A method by which project correlation may be estimated based on experience and judgement is proposed. The method utilizes the fuzzy set theory to estimate the coefficient of correlation and the judgement uncertainty. Then, the total risk of a portfolio can be estimated.

ISSN:0263-0257    

DOI:10.1080/02630259008970585

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A methodology is presented to explore the tradeoffs associated with the numerous solutions typically obtained through multiobjective optimization procedures. The method is a graphical surface navigation technique based on a spring equilibrium analogy. The procedure is cast in the framework of an interactive graphical session, which permits a user easily to move from one noninferior point to another on the objective response surface. A zooming capability is also incorporated which facilitates refinement of the noninferior set approximation over particular areas of interest and as well, provides for the capability to examine the exact noninferior set. A three-dimensional and a five-dimensional problem are used to illustrate the method.

ISSN:0263-0257    

DOI:10.1080/02630259008970586

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259008970587

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630259008970588

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor