Comparing Fuzzy and Probability Calculus for Representing Imprecision in Preliminary Engineering Design

1989 ◽  
Author(s):  
K. L. Wood ◽  
E. K. Antonsson ◽  
J. L. Beck
Keyword(s):  
Fuzzy Sets ◽  
Engineering Design ◽  
Stochastic Uncertainty ◽  
Probability Calculus ◽  
Fuzzy Calculus ◽  
Design Calculations

Abstract A technique to perform design calculations on imprecise representations of parameters using the calculus of fuzzy sets has been previously developed [17]. An analogous approach to representing and manipulating uncertainty in choosing among alternatives (imprecision) using probability calculus is presented and compared with the fuzzy calculus technique. We find that the fuzzy calculus is well suited to representing and manipulating the imprecision aspect of uncertainty, and probability is best used to represent stochastic uncertainty.

A First Class of Computational Tools for Preliminary Engineering Design

1988 ◽  
Author(s):  
K. L. Wood ◽  
E. K. Antonsson
Keyword(s):  
Fuzzy Sets ◽  
Engineering Design ◽  
Preliminary Design ◽  
Functional Requirement ◽  
Computational Tool ◽  
Computational Tools ◽  
Input Parameters ◽  
Implementation Scheme ◽  
Design Calculations ◽  
Fuzzy Parameters

Abstract Preliminary engineering design intrinsically consists of imprecise descriptions of the input parameters. We present new conceptual and algorithmic procedures for dealing with such imprecise descriptions. Specifically, a two-part method is outlined for performing design calculations on these “fuzzy” parameters, as well as determining a measure for the parameters’ coupling. By interpreting the input set of variables for preliminary design in terms of fuzzy sets, we demonstrate how the engineer may associate his subjective meaning with the input parameters and the output functional requirement, leading to the foundation of our approach. An example of the method highlights the primary issues and the implementation scheme as a computational tool.

Computations with Imprecise Parameters in Engineering Design: Background and Theory

1989 ◽  
Vol 111 (4) ◽  
pp. 616-625 ◽  
Author(s):  
K. L. Wood ◽  
E. K. Antonsson
Keyword(s):  
Engineering Design ◽  
Weighted Average ◽  
Design Parameters ◽  
Average Technique ◽  
Design Elements ◽  
Input Design ◽  
Fuzzy Calculus ◽  
Design Calculations ◽  
Imprecise Parameters ◽  
Preliminary Phase

A technique to perform design calculations on imprecise representations of parameters has been developed and is presented. The level of imprecision in the description of design elements is typically high in the preliminary phase of engineering design. This imprecision is represented using the fuzzy calculus. Calculations can be performed using this method, to produce (imprecise) performance parameters from imprecise (input) design parameters. The Fuzzy Weighted Average technique is used to perform these calculations. A new metric, called the γ-level measure, is introduced to determine the relative coupling between imprecise inputs and outputs. The background and theory supporting this approach are presented, along with one example.

Introduction

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Fluid Flow ◽  
Engineering Design ◽  
Ocean Waves ◽  
Basic Design ◽  
Natural Phenomena ◽  
Turbofan Engine ◽  
Expansion Waves ◽  
Supersonic Aircraft ◽  
Bodily Fluids ◽  
Design Calculations

In this chapter the wide array of engineering devices, from the kitchen tap (a valve) to supersonic aircraft, the basic design of which depends upon considerations of the flow of gases and liquids, is shown. Much the same is true of most natural phenomena from the atmosphere and our weather to ocean waves, and the movement of sperm and other bodily fluids. In this textbook a number of the concepts, principles, and procedures which underlie the analysis of any problem involving fluid flow or a fluid at rest are introduced. In this Introduction, examples have been selected for which, by the end of the book, the student should be in a position to make practically useful engineering-design calculations. These include a dam, a rocket motor, a supersonic aerofoil with shock and expansion waves, a turbojet engine, a turbofan engine, and the blading of a gas turbine.

Imprecision in Engineering Design

1995 ◽  
Vol 117 (B) ◽  
pp. 25-32 ◽  
Author(s):  
E. K. Antonsson ◽  
K. N. Otto
Keyword(s):  
Decision Making ◽  
Fuzzy Sets ◽  
Engineering Design ◽  
Cost Estimation ◽  
Formal Method ◽  
Concurrent Design ◽  
Design Decision ◽  
Design Cost ◽  
Formal Information

Methods for incorporating imprecision in engineering design decision-making are briefly reviewed and compared. A tutorial is presented on the Method of Imprecision (MoI), a formal method, based on the mathematics of fuzzy sets, for representing and manipulating imprecision in engineering design. The results of a design cost estimation example, utilizing a new informal cost specification, are presented. The MoI can provide formal information upon which to base decisions during preliminary engineering design and can facilitate set-based concurrent design.

Fuzzy Set Based Models in Design Optimization

1988 ◽  
Author(s):  
A. R. Diaz
Keyword(s):  
Multiobjective Optimization ◽  
Design Optimization ◽  
Fuzzy Sets ◽  
Engineering Design ◽  
Goal Programming ◽  
Fuzzy Set ◽  
Optimization Problem ◽  
Traditional Methods ◽  
Multiobjective Problems

Abstract A formulation for multiobjective optimization for engineering design based on fuzzy sets is presented. Models for the optimization problem and operations to introduce model variations are described formally. Under a reasonable set of rules it is shown that solutions to fuzzy multiobjective problems are weakly efficient and can reproduce solutions obtained by traditional methods such as compromise and goal programming. Results are easily implemented in computations.

A Fuzzy Sets Approach to Computational Tools for Preliminary Engineering Design

1987 ◽  
Author(s):  
K. L. Wood ◽  
E. K. Antonsson
Keyword(s):  
Fuzzy Sets ◽  
Engineering Design ◽  
Data Driven ◽  
Preliminary Design ◽  
Engineering Structures ◽  
Design Decisions ◽  
Computational Tools ◽  
Alternative Technologies ◽  
Imprecise Parameters ◽  
Preliminary Phase

Abstract The primary goal of this research is to provide computational tools, or aids, to engineering designers, particularly for the preliminary phase of design. Such aids will be particularly useful in choosing between alternative technologies. Design choices of this nature are perhaps the most critical, and likely to be the most costly if in error. Our approach has been to aid preliminary design decisions with analysis tools developed for computations on imprecise parameters. Contemporary computers and algorithms are not well suited for manipulating imprecise descriptions of objects. To provide these basic tools, we are applying the mathematics of fuzzy sets. This approach (along with “data-driven programming”) appears to be well suited to our problem and has been applied to similar problems in analyzing civil engineering structures and failures.

Engineering design calculations with fuzzy parameters

1992 ◽  
Vol 52 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Kristin L. Wood ◽  
Kevin N. Otto ◽  
Erik K. Antonsson
Keyword(s):  
Engineering Design ◽  
Design Calculations ◽  
Fuzzy Parameters
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