摘要:

This paper describes an experimental facility for use in wind‐tunnel studies of highly threedimensional flows. The system is microcomputer controlled, incorporating a precision probe‐traversing mechanism with five degrees of freedom and pressure‐measuring apparatus with on‐line data acquisition and analysis. The experimental setup is illustrated and discussed in detail, together with examples of practical applications of the f

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00248.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

“Pavement Expert” is an expert system developed to aid in the evaluation of concrete pavements. The system is operational on an IBM microcomputer. It guides the engineer through the evaluation procedure, ensures that it is carried out adequately, and that it can be independently repeated by other engineers. “Pavement Expert” operates in two modes: dialogue and data rogging modes. The dialogue mode is controlled by a Savoir shell which controls the dialogue between the user and the system. The system makes decisions “intelligently” concerning the length of the section to evaluate, extent and severity of the observed distresses, and calculates and stores the final indices. The data logging mode acts as an intelligent data logger recording specific observed distresses. This information is presented graphically on the screen, allowing for alterations to be made. The system consists of five stages ranging from identifying the road to providing a full report on the general condition of t

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00249.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

An expert system is developed for evaluating transportation network improvement alternatives with multicriteria. The advantages of this system are 1) integrating data, transportation models, and evaluation methods within one framework; 2) applying multicriteria evaluation methods and choice rules for these methods onto various evaluation environments; and 3) providing a friendly man‐machine interface. First, a transportation network improvement evaluation problem is specified. Then, an expert system is formulated. The relative data bases, model bases, and knowledge bases are described. Finally, a brief example is used to demonstrate the practicality of the system. The whole program is an integration of LOTUS 123, Turbo PROLOG and C language programs on an IBM personal compute

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00250.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

A family of mixed‐time integration methods applicable to first‐order systems of equations which are amenable to parallel computations are presented. The method is based on nodal partitioning and can allow different values of α in the α‐algorithm to be used in different subdomains of the mesh. Parallelism is introduced by allowing each subdomain to be updated independently over a time step. A stability analysis is given for the case of implicit—explicit and implicit—implicit integration. Several numerical examples are given to demonstrate numerically the accuracy and stability of

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00251.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

An efficient and robust optimization algorithm is presented for minimum weight disign of continous multispan steel plate girders using the general geometric programming technique. The loading on the girder can consist of any number of concentrated and uniformly distributed loads. The nonlinear programming problem is formulated on the basis of the last edition of the American Institue of Steel Construction (AISC) specification. The desing variables are the flange width and thickness, teh web depth and thickness, and the dimensions and spacings of the transverse stiffeners for stiffened plate girders. In the optimization algorithm, the nonlinear primal problem is transformed to and via double condesation. The algorithm is quite general and can be applied to stiffened of unstiffened, homogeneous or hybird plate girders. The girder may be fully restrained agained lateral torsional buckling or may haae lateral supports only at selected locations along the length ofthe girder. The algorithm id implemented in FORTRAN 77 in an interactive computing environment with graphic capabilities. The grogram can display the plate girder elevtion, various cross sections, and loading on the girder. Three examples are presented, a two‐span homogeneous, a three‐span hybird, and a five‐span homogeneous plate g

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00252.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

A microcomputer‐oriented semianalytical method of solution is presented for rectangular plates with variable rigidity or thickness. The solution procedure is based on the classical method of separation of variables. The two‐dimensional governing partial differential equation is first reduced to and ordinary difference equation. The classical unidirectional finite‐difference method is then employed to solve the resulting ordinary differential equation. Results are presented for plates with different edge and loading conditions. Results for partially loaded plates with variable rigidity or thickness are presented in the literature for the first

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00253.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The present paper describes the computer adaption of the classical graphical technique developed by Newmark in 1942, for the computation of the axial stresses within an elastic soil mass. The paper describes the essential features of the computer implementation procedure and presents results for ceratin specific cases in which the surface of the elastic half‐space region is subjected to uniformly distributed loads of finite exten

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00254.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

This paper presents computational results from implementations of two previously published but untested algorithms for solving a class of very large problems arising in transportation: singlecommodity spatial price equilibrium problems with nonlinear excess demand fundtions. An indirect algorithm solves an approximating sequence of linear subproblems in a Newton‐like iteration. A direct algorithm modifies the min‐ratio test of the algorithm used for solving linear subproblems to accommodate the nonlinear excess demand functions, thus solving the problem directly. Although the direct algorithm is seemingly more elegant and would appear on the surface to be more efficient, we present evidence to support the hypothesis that unavoidable computational overhead required by an implementation of the direct method renders it far less efficient in most cases than the indirect met

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1988.tb00255.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY