Wolter J. Fabrycky

An input/output control system for the dynamic job shop

Abstract A combined input/output control system is presented for periodically determining the set of jobs to be released (input variables) and the capacities of processing centers (output variables) in the dynamic job shop, so that a composite cost function is minimized. An interactive heuristic optimizing algorithm incorporating a 0–1 linear mixed integer program is formulated. The resulting control system is compared by simulation with an alternate system for which only input is subject to control. Significant improvements are obtained for most performance measures evaluated.

Decision evaluation with interval mathematics: a power distribution system case study

A decision evaluation methodology which considers both economic and performance aspects is presented. Interval mathematics is used in economic modeling. Interval mathematics eliminates the need for multiple sensitivity studies associated with input parameter variations. A decision evaluation vector and display for distribution systems are proposed. The methodology is applied to a distribution system case study. Results of the case study are presented. >

Fuzzy set based multi‐attribute conceptual design evaluation

Identification of a need or functional/performance deficiency initiates conceptual design. Methods such as Quality Function Deployment (QFD), Checklists and Taxonomies (CAT), and Input/Output Matrices (IOM) provide a framework for translating a need into specific qualitative and quantitative customer requirements. Design concepts and technical solutions are then generated to address these requirements. This paper represents an extension of ongoing research in the application of fuzzy set methods to evaluate design concepts. Since imprecision and vagueness characterize this nascent design phase, the QFD method and Pughs concept selection process are modified and extended with concepts from fuzzy set theory [Verma, 1994; Verma and Fabrycky, 1995]. This fuzzy set based extension provides a rigorous mechanism for dealing with imprecise requirements and priorities, as well as the subjective correlation between customer and design requirements. Furthermore, the approach presented herein is discussed from the perspective of invoking Taguchis loss function during design concept feasibility analysis within conceptual system design.

Systematically identifying system engineering practices and methods

Proper implementation of system engineering (SE) concepts and principles requires a breakdown of the overall SE process into specific activities and tasks. For maximum effectiveness, appropriate SE practices and methods should be identified, selected, adapted, and then applied in an integrated manner. A systematic approach to identify relevant practices and methods, as a function of the phase of the system design and development process, is developed. A brief survey of SE practices is included to illustrate the application of this approach.

THE APPLICATION OF INTERVAL ANALYSIS TO ECONOMIC DECISION EVALUATION OF ELECTRIC ENERGY SYSTEMS

Abstract A general model for decision evaluation is presented which consists of engineering, economic, and decision evaluation submodels. The methodology utilizes interval mathematics, which offers a new approach to modeling parameter uncertainty and transforms results from the engineering and economic models into indices that are used for performing pairwisc comparisons between alternative designs A distribution case study which considers eight alternative designs is presented. Sample results are presented in terms of the proposed decision evaluation vector and display.

A CAPITAL BUDGETING MODEL BASED ON THE PROJECT PORTFOLIO APPROACH: AVOIDING CASH FLOWS PER PROJECT

ABSTRACT The widely used concept of a cash flow per project in capital budgeting has serious weaknesses when resources are shared by different projects. Accordingly, the concept of cash flow per project is not used herein. Instead, the project portfolio approach is used in which costs are considered only in the acquisition and utilization of resources; when these costs actually occur. The main conclusion from this approach is that better capital budgeting decisions can be made if the concept of cash flow per project is avoided when resources are shared.

THE NSF SPONSORED RESEARCH PLANNING CONFERENCE ON ENGINEERING ECONOMICS

Abstract Editors Mote: In recent tines It has been recognized by academics and practitioners in the field of engineering economics of the necessity of an active, continuing research program. Such s program will provide improvements in the state-of-the-art along with development of the manpower required Co carry on the profession. In 1983, specific activities were initiated to increase the awareness of research activity within the profession and to identify those research areas of greateat need or promise On August 24–29, 1984, the National Science Foundation sponsored the Research Planning Conference on Engineering Economics at Mountain Lake, Virginia. The following report describes this important meeting and the recommendations that resulted. Because of the importance of this meeting to the profession, this summary has been Included here. The proceedings resulting from this planning conference are available free of charge by contacting U. J. Fabrycky, Department of Industrial Engineering and Operations ...