Set Of Design Specifications Research Articles

FIESTA-a filter educational synthesis teaching-aid

The authors describe a circuit synthesis program called FIESTA and its use is a teaching tool in both undergraduate and graduate courses. The program is very easy to use, is highly interactive, and contains graphics capabilities to give the student insights in active RC-filter design. FIESTA makes easier and faster the solution of the filter approximation problem, which traditionally involves use of tables and nomographs for a selected number of specifications. It is especially practical when a set of design specifications is not included in the tables. Highlights include Butterworth, Chebyshev, and Cauer approximations, and an arbitrary group-delay approximation. Circuit implementation is done using for illustration the Tow-Thomas biquadratic active RC-filter as the main basic block. Several computer exercises are suggested to complement classroom lectures and traditional 'paper and pencil design'. Addition of code is easy to implement in FIESTA. >

Field applications of prestressed laminated wood bridge decks

The concept of prestressing laminated wood bridge decks was conceived in Ontario in 1976 as a method of upgrading existing deteriorated nailed laminated wood decks. The success of this technique as a method of rehabilitation prompted considerable research and development aimed at introducing it into new construction. This work led to the formation of a comprehensive set of design specifications, which have since been adapted into the Ontario highway bridge design code and were included in the 1983 edition.Since its inception in 1976, the prestressed wood concept has been used many times, and by 1985, more than 16 bridges incorporated the concept in various ways. The objective of this paper is to discuss a number of these field structures in order to demonstrate the flexibility of the prestressed wood deck system. In new construction, the system has been applied to both longitudinally and transversely laminated decks including on-site deck assembly as well as a preassembled deck panel system.The paper describes the applicability of the system, construction sequence, and field problems. In addition, construction costs for some of the applications, as derived from field data, are discussed. Key words: wood, bridges, prestressed wood decks, laminated decks, preassembled deck panels.

A knowledge based approach to automate forging design

This paper describes a method and a system to automate the design of forging geometries. The method is derived from the principles and the actual practices of forging design used by experienced forging designers. Due to the diversity of the knowledge and problem solving techniques required for forging design, a combination of knowledge-based and algorithmic techniques was employed to implement the AFD (automated forging design) system. Given a set of design specifications, that is, machined part geometry, processing conditions, and special design considerations, the AFD system designs the forging section geometry automatically. Initial results from AFD show that it can be a powerful tool for designing geometries for the rib-web type of forgings.

A network based expert system for intelligent design of mechanisms

Linkage-type mechanisms have numerous applications in industry especially for automation Unfortunately, they are less popular due to lack of proper design tools. This paper describes our efforts to remove the technological barrier in mechanisms design automation. Although the ideas presented apply to automation of mechanisms design in general, the paper discusses the development of an expert system for a particular sub-set of mechanisms called Dwell mechanisms.Many essential and desirable motion characteristics of mechanisms are so implicit that they are difficult to control by analytical methods. By systematically and extensively studying the entire motion characteristics of hundreds of linkages, a comprehensive classification system and heuristics were developed. This qualitative classification scheme led to a finite set of linkage models that cover the entire design space in the sense that any possible design falls under one or more of the models. Our system, called Dwell-Expert, incorporates this design expertise to select the best linkage model for a given set of design specifications and to compare that model against alternatives. The new design methodology and its implementation in AGNESS (A Generalized Network-based Expert System Shell) are explained. A design example is also presented. Our system can reduce even an experienced designer’s initial-design time from a day or more to a minute or less, assuming specifications have already been formulated. Such results motivate extension of this design methodology to other areas of mechanical design and engineering design in general.

MINOPT--An Optimization Program Based on Recent Minimax Results (Computer Program Descriptions)

To solve design problems in which the objective is to best satisfy a given set of design specifications or constraints in the least pth or minimax sense, assuming the availability of first partial derivatives of the functions concerned with respect to the design parameters.

A Statistical Approach to the Design of Diffused Junction Transistors

Monte Carlo methods of statistical analysis are applied to the problems of transistor design and optimization. The experimental tolerances associated with any diffusion process are shown to represent an important factor in the initial design of diffused junction transistors. Many transistor parameters exhibit a substantial degree of sensitivity to small variations in the diffusion process. This is confirmed by a comparison between the theoretical and experimental open-base breakdown voltage, and current gain, for a large number of devices. It is therefore proposed that the design of a transistor be based upon attaining a specified set of electrical characteristics when the device is assumed to be fabricated by a non-ideal diffusion process. An electronic computer has been used in an investigation of the foregoing problem. The investigation shows further that a margin-of-safety must be designed into each electrical parameter of a transistor to assure that the resulting device satisfies a given set of design specifications, even though this margin-of-safety may differ for each parameter. In this paper examples are presented to illustrate the theoretical trade-off between several opposing transistor parameters that exhibit a substantial degree of variability due to a non-ideal diffusion process.

Transistorized Pacemaker for Remote Stimulation of the Heart by Radio-Frequency Transmission

Diverse techniques have been developed for controlling the cardiac rate by external means when normal physiological processes fail to maintain a stable rate. These techniques are presented in a brief summary. The factors underlying the choice of the radio-frequency transmission technique are presented and evaluated, taking into account control of the stimulus, avoidance of infection, and minimizing the number of electrical components within the body. A set of design specifications is then evolved based upon the physiological needs of the patient, utilizing the philosophy of the RF transmission approach. The design of two transistorized, battery-operated pacemakers is then presented in detail with a description of the constructed units and an evaluation of performance. These units have now been used successfully on five patients.