Simple Design Problem Research Articles

Electronics for the beginner (with the physics teacher in mind). The logic gate: Part 1

This is the first of a series of articles covering electronics material which is common to A-level physics syllabuses offered by the various examination boards. The articles are aimed at teachers who are not familiar with this area of study. The first deals with elementary Boolean algebra and the AND, OR, NOT gates. The second will be concerned with NAND and NOR gates and will include a simple logic design problem. Further articles will study the operational amplifier.

Electronics for the beginner (with the physics teacher in mind). The logic gate: Part 2

This is the second of a series of articles covering electronics material which is common to A-level physics syllabuses offered by the various examination boards. The articles are aimed at teachers who are not familiar with this area of study. The first article dealt with elementary Boolean algebra and the AND, OR, NOT gates. Copies of this may be obtained from the Editor of Electronic Systems News. This second article is concerned with NAND and NOR gates and includes a simple design problem. Further articles will study the operational amplifier.

A note on design when response has an exponential family distribution

SUMMARY Some simple design problems are considered when responses have an exponential family distribution with the difference between 'treatment' groups in the canonical parameter being the objective of study. It is shown that normal theory conclusions apply to a possibly surprising extent. The loss from randomizing followed by subsequent stratification is the equivalent of one observation per stratum. For binary data heterogeneity has to be quite large before failure to stratify induces serious loss, whereas unnecessary use of a matched pair design is fully efficient asymptotically.

CAD for Pneumatic Circuit Design in Low Cost Automation

This paper describes the design of a CAD system for pneumatic sequential control. A special language for describing the sequence is developed. The procedure of memory designation and function generation, switching function minimization, and circuit construction is described in detail. Referring to a simple design problem, the computer process from the high level language statement to the pneumatic circuitry is illustrated. Finally, the application of the design package to other control problems is outlined.

Truss Design: Two Loading Conditions with Prestress

This paper reviews the effect of prestress on a simple truss design problem with two loading conditions. Optimality criteria are formulated on the “sum” and “difference” problems. These criteria are subsequently interpreted to imply that the optimal design is fully stressed and to develop an iterative design scheme. Examples are included.

Inverse Transonic Wing Design Method

An inverse, transonic flow method for the design of three-dimensi onal wings has been developed. The flow method is based on a three-dimensional, finite-differ ence solution of the full-potential equation. The inverse scheme utilizes a Dirichlet boundary condition in conjunction with surface transpiration to affect geometry definition. Such a scheme has previously been utilized in a two-dimensional method. This paper summarizes an analogous development for three dimensions. Basic steps and underlying assumptions of the inverse scheme are described. Applications of the method to both simple and complicated design problems are discussed and advantages of the method are identified.

A Sufficient Test for Global Optimality with Signomial Design Applications

A general, sufficient test for proving a local minimum to be the global minimum is presented. The test uses a special lower bounding function and methods for constructing this special bounding function for univariable or multivariable unconstrained signomial design problems are given. Two simple design problems illustrate the use of the constructions and test.

On Product Reliability Under Random Field Loads

This paper presents a simple design problem to illustrate the relationship between product reliability and design strength for the case where product failure is due to a single overload in a sequence of loads applied during the mission of the product.

On Probabilistic Design

The probabilistic approach to design is developed and contrasted with the conventional safety factor approach. A careful interpretation of random variable design inputs is given, leading to a statistical extreme-value model of loads. In addition to the “reliability” concept, the concept of “mission length” is explicitly introduced to the design process. A simple design problem, involving random variable loads and constant material properties, is solved and illustrated. Possible extensions of this design problem, and their likely difficulties, are indicated.

On the optimum design of thin-walled compression members

Current discussions concerning the validity of simultaneous buckling as a criterion of optimization are quantified by the formulation of a simple design problem for a thin-walled strut. Here, simultaneity of overall and local buckling leads to a well-defined optimum for a perfect column, and recent calculations by A. van der Neut are used to examine the extent to which this optimum can be eroded away by imperfection-sensitivity associated with coupled-branching behaviour. The optimum is seen to shift quite significantly for small imperfections, and for larger ones it can be entirely eliminated.

Analysis and Design of Tower Foundations

A comprehensive set of design procedures for tower foundations of the drilled shaft type is presented. Included is an analysis of various soil types, soil testing procedures, and interpretation of field and laboratory test results. Procedures are developed separately for horizontal shear, compression, and uplift in various soil types. The structural design of the reinforced concrete shaft for combined uplift and bending is presented as well as cases involving compression at extremely high eccentricities. Computer generated design aids are presented which offer some relief from tedious calculations. Two simple design problems are used to illustrate the developed procedures.

Artificial Intelligence and Structural Design

A review of some of the literature concerned with questions of artificial intelligence is presented and particular attention is paid to work which may be applied to problems of structural design. The possibility of an adaptive structural design system is examined and a simple design problem is used to illustrate some aspects of learning behavior.

Aids for the Gross Design of Satellite Communication Systems

Satellite communication systems are being proposed with ever-increasing frequency as integral components of many future commercial, military, and space programs. Thus, many people in all levels of engineering, management, government, and military occupations are being called upon to deliver judgments on this new mode of communications. However, there are sometimes difficulties in developing these judgments, because even gross design of satellite communication systems requires simultaneous manipulation of a half dozen or more parameters. This paper has been compiled as a computational aid for designers and reviewers of communication systems employing earth satellites as relays. Pertinent design equations are introduced and discussed briefly, with special emphasis placed on the limitations of the equations and the ranges of the parameters. Many of the computational aids, such as charts and nomographs, that are applicable to the gross design of satellite communication systems are presented. The utility of these computational aids is demonstrated in the solutions of some simple satellite communication system design and analysis problems. This paper is intended to be of practical usefulness; there is no suggestion that the theory of communications or satellites is probed in depth or detail.