摘要:

The purpose of this paper is to present an application of fuzzy logic as an organizational framework for a knowledge-based interpretation system in the domain of geotechnical engineering. Knowledge-based systems (KBS) are emerging as a powerful means of dealing with the ill-structured problems encountered in many engineering and medical applications1. (It has been stated2 that expert systems are problem-solving programs that solve substantial problems generally conceded as being difficult and requiring expertise. They are called knowledge-based because their performance depends critically on the use of facts and heuristics (or rules of thumb) used by experts). In a KBS, the knowledge or rules of judgement pertaining to the domain are encoded in the system in an explicit manner; these rules can be examined and modified, if necessary. This is in contrast to the way traditional algorithmic programs are structured. The motivation for this project was two-fold: generally, to demonstrate that knowledge-based techniques are powerful problem-solving tools that can be applied to task areas within geotechnical engineering; and specifically, to develop a KBS to interpret geotechnical characterization data from cone penetrometers.

ISSN:0263-0257    

DOI:10.1080/02630258608970429

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper has four objectives. Firstly, modifications are recommended and presented to a well known set of US Army test data representing eleven tests that involve destruction of buried concrete box structures by ground transmitted shock waves. The resultant database is available for failure mode analysis. Secondly, a new approach forfailure mode analysis based on pattern recognition techniques to the structural engineering community is introduced. Thirdly, a comparison is presented of the results of preprocessing, feature extraction, and cluster analysis for failure modes to several previous studies. The objective here is to inform the structural engineering community about data interpretations that can be inferred using this approach; the authors do not claim to have a conclusive or definitive classification of failure modes in these data. Finally, the importance of a priori decisions about data analysis during the planning stages of physical experiments is emphasized by pointing out the many statistical and other uncertainities that are associated with the data being discussed.

ISSN:0263-0257    

DOI:10.1080/02630258608970430

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A procedure for combining human errors in structural risk analysis is presented. The procedure accounts for the fact that human errors cause unconservative and/or conservative changes in the probability density functions of the basic variables (i.e. resistance and load effect) involved in the structural risk model. The paper also includes results with regard to the sensitivity of the reliability index to changes in (a) the type of individual errors, (b) the type of combination of errors, and (c) the probability of occurrence of such errors. The results could be used to evaluate the significance of various combinations of errors on structural risk.

ISSN:0263-0257    

DOI:10.1080/02630258608970431

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A range of successively more elaborate elastic models is developed, with responses that in many ways mimic those of plastic specimens under load. The bilinear stiffness of a simple one degree-of-freedom elastic prop, which experiences a symmetric point of bifurcation, is first used to model the fundamental elasto-plastic response: the introduction of an imperfection corresponds to the Ramberg-Osgood approximation, rounding off the bilinearity. Upper and lower yield points are reproduced by a model termed the elastic hook, in which an elastic spring of the first model is itself replaced by an elastic prop with a bilinear stiffness. Finally, the normality relation of incremental plasticity theory is reproduced by two props at right-angles: responses are also traced for two hooking models in this configuration, for which no real comparison in plasticity theory seems to exist at present.

ISSN:0263-0257    

DOI:10.1080/02630258608970432

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A new approach to the distribution of gas in a large network is suggested. Instead of minimizing running costs, the authors propose the minimization of power changes of the gas stream through the pipes of the whole system. For this purpose, the specific enthalpy of the gas is used. An example is given in which the gas network includes three compressor stations and 37 pipes. Running costs and power changes of the gas stream have been calculated for this example so that a comparison between the two objective functions can be made.

ISSN:0263-0257    

DOI:10.1080/02630258608970433

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0263-0257    

DOI:10.1080/02630258608970434

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor