Use Of Analog Computer Research Articles

The promise of analog computation

Future computing paradigms and technologies will have to be more like the physical processes by which they are realized, and because these processes are primarily continuous, post-Moore’s law computing will involve an increased use of analog computation. Traditionally analog computers have computed ordinary differential equations of time, but analog field computation permits massively parallel temporal integration of partial differential equations. In principle many different physical media – not just electronics – can be exploited to implement the basic operations of analog computing, a small number of which are sufficient to approximate a wide variety of analog computations, thus providing a basis for universal analog computation and general-purpose analog computers. The contentious issue of the computational power of analog computers is addressed best on its own terms, rather by asking it within the context of Church-Turing computation, which distorts the relevant questions and their answers.

Analog Computations and Current Problems of Automatic Control

The widespread use of analog computation in the past is no longer the case. It implies not only shutting down one of the sectors consuming analog microcircuits. In fact, it leads to narrowing the “knowledge base” on automatic control with a subsequent bias in training of the specialists. The way out can be found in wider application of analog computing subsystems, for instance, in testing predictive algorithms for moving objects control and by analysis of chaotic systems. There is hardware available and research to support such developments.

Analog computers in academia and industry: a history of analog computing at the University of Michigan and the founding of Applied Dynamics International

This article recounts the author's personal history as a graduate student and faculty member at the University of Michigan and as a founder of Applied Dynamics International (ADI). It traces the use of analog computers in various research projects for the US Air Force, Rand Corporation, and the Office of Naval Research, including the development of a simulator for aircraft flight equations with six degrees of freedom. It also discusses the founding of ADI in 1957 and the development of their product line of analog computers.

CMOS Analog MAP Decoder for (8,4) Hamming Code

Design and test results for a fully integrated translinear tail-biting MAP error-control decoder are presented. Decoder designs have been reported for various applications which make use of analog computation, mostly for Viterbi-style decoders. MAP decoders are more complex, and are necessary components of powerful iterative decoding systems such as turbo codes. Analog circuits may require less area and power than digital implementations in high-speed iterative applications. Our (8, 4) Hamming decoder, implemented in an AMI 0.5-/spl mu/m process, is the first functioning CMOS analog MAP decoder. While designed to operate in subthreshold, the decoder also functions above threshold with a small performance penalty. The chip has been tested at bit rates up to 2 Mb/s, and simulations indicate a top speed of about 10 Mb/s in strong inversion. The decoder circuit size is 0.82 mm/sup 2/, and typical power consumption is 1 mW at 1 Mb/s.

Use of analog computer to investigate valveless pneumopercussive mechanism with single driven chamber

Use of analog computer to investigate valveless pneumopercussive mechanism with single driven chamber

Briefly Now, More Later

I think I can best let Vince Rideout tell it for himself: "When I was a new assistant professor (about 1948) in the EE Department of the University of Wisconsin, struggling to introduce our first auto matic control course, my chairman, Harold A. Peterson, got me interested in the idea of using some of the new electronic analog computers in connection with this work. We purchased some Philbrick 'boxes,' and have been simulating ever since. During the summer of 1951 I worked for Boeing in Seattle and got some further familiarity with the use of analog computers there, and even more as a consultant for Allis Chalmers from 1956 on. In 1954 when I went to Bangalore.. India for a year at the Indian Institute of Science, I took along some plug-in op-amps., etc. and built India's first analog computer there. About 1964 I began to work on cardiovascular system simulation, and continue to do so. Also, about 1965 I was instrumental in getting a large hybrid instal lation at Wisconsin, and was director of our hybrid laboratory until 1972, when I left to become depart ment chairman. Since leaving the chairmanship a year ago, I have become interested in two new fields of research-array computer design and large-scale socioeconomic modeling."

Use of analogue computers to model the interaction between support and the strata. In Polish : OLASZOWSKI, W PRZEGL. GORN. V31, N10, 1975, P387–392

Use of analogue computers to model the interaction between support and the strata. In Polish : OLASZOWSKI, W PRZEGL. GORN. V31, N10, 1975, P387–392

SHAC-a simple homogeneous analogue computer. I

With a view towards a more generalised use of analogue computers in schools for improving existing physics courses, the author discusses the specifications of a school built analogue computer.

The use of the analogue computer in pesticide research

AbstractThe basic components of a general‐purpose analogue computer are described in terms of their operational functions. Their use in pesticide research has been extremely limited but such examples as exist are reviewed.Examples of the use of analogue computers are given. These include the simulation of single and consecutive first‐order reactions, the sorption‐desorption processes affecting the availability of pesticides in soils, diffusion and leaching in soils and the build‐up of residues in soils following repeated annual applications to the soil surface.

Use of analog computer in heat transfer study

Use of analog computer in heat transfer study

Some Questions Concerning the Application of the Sensitivity Theory to an Analysis of Transient Processes while Simulating Systems with Distributed Parameters on Analog Computers

At present, analog computers are widely used to analyse systems with distributed parameters. So far the main method of such an analysis has been that of direct simulation. The sensitivity theory has alreacty been developed to analyse other systems on analog computers. In this paper the mechanism of the sensitivity theory is used for systems involving a component element with distributed parameters in studying the effect of the parameters on the behaviour of a transient process. Finding of parameters having little effect brings about a simplification of the mathematical description and simulation of the system because these parameters are ignored. However, the evaluation of parameters characterized by a strong effect facilitates the control of transient processes and their optimization so the problem of estimation of the parameters neglecting appears. Based on engineering experience a problem is also posed consisting in that the parameters which are difficult to simulate should be allowed for in other parameters leading to a more simple mathematical model. This paper deals with a structural method of simulation developed to simulate transient processes and allowing to draw up block diagrams of a system model and sensitivity directly from the basic diagram of the system, without the need of presenting its mathematical description. The system model is visualized as a total combination of elementary block diagrams. In this case a particular elementary block diagram corresponds to each element of the basic diagram and to the nodal point as well. In doing so, the block diagram of the model of a basic-diagram element is defined by the subgraph, since the subgraph gives the connection diagram of computing elements with transfer constants corresponding to the transfer constants of branches. Eased on above stated a library of subgraphs and corresponding structural block diagrams of different elements of electrical system with distributed parameters was compiled. To obtain sensitivity models of electrical systems with distributed parameters, a library of sensitivity subgraphs and corresponding elementary block diagrams were compiled. This library was derived from the library of subgraphs of the systems of elements based on special rules, developed for this purpose. In order to extend structural simulation with the use of analog computers to sensitivity with respect to the final variations of parameters and to obtain the analytical dependence of the variation of an unknown variable on the variable parameter, high-order derivatives are used in evaluating the sensitivity of the considered system. The number of terms, wich is sufficient for accurate determination of such changing is controled by the remanent term in form of Lagrange for expression of expansion unknown quantity in Talor's series. The analog junction block is developed for finding sensitivity junctions on analog computer allowing to form, store, and supply, in case of necessity, a successive series of high-order derivatives on the basis of a given parameter. Methods devised to use the sensitivity theory for analysing transient processes dealt With in this paper have been checked in simulating electrical systems with distributed parameters by analog computers. Numerical results have been obtained which allow to evaluate the following factors for a particular system. 1.Sensitivity functions on the basis of different parameters of an electrical system with distributed parameters while simulating by means of an automatic computer;2.The effect of the long-line length on the errors of simulating the above systems by an automatic computer which are due to the inaccuary of the coefficients specified;3.The error due to ignoring the losses distributed over the long line;4.The possibility of the losses distributed over the long line to be taken into account by resistances concentrated at a number of line points without losses.

An analog computer in hybrid loops

In the article new problems dealing with the use of analog computer in hybrid loops are discussed, among them a review of the methods concerning optimal determination of scale factors and transfer coefficients. New approach is introduced based on the notion of optimal scales vector. Two ways of analog set-up diagrams synthesis mechanization with the digital computer help are presented : transformation of the differential equations original system to the system of first order differential equations, compiling and equivalent transformation of the unidirected graph corresponding to the given differential equations. Besides that, an account of the known automatic adjusting systems is given.

On the measurement of resistor dynamic characteristics

This paper is a summary of two techniques for the meas urement of resistor dynamic characteristics. It is not a comprehensive paper in that it does not include a liter ature search or a review of well-established bridge tech niques. It does, however, present methods of measuring resistor high- and medium-frequency dynamic characteris tics, using only a square-wave generator, a sine-wave generator, and a high-speed oscilloscope. It emphasizes the use of models, both physical and mathematical, and completely avoids the use of analog computer measuring methods, even though the practical goal is analog-compu ter oriented.

SOME APPLICATIONS OF ANALOGUE COMPUTERS TO TEACHING

SUMMARY The use of analogue computers for teaching purposes has considerable application in relation to anaesthesia. Examples are presented of hydrodynamic and electronic analogues expressing the complex relationships involved in carbon dioxide and oxygen stores, and in the uptake of general anaesthetic agents.

The use of analog computers for teaching chemistry

Examines the mathematical operations of basic electrical components, the method of programming an analog computer, and using an analog computer to solve problems of chemical interest.

Use of analog computers in anesthetic research.

Use of analog computers in anesthetic research.

On Using an Analog Computer to Study Hydrodynamic Stability

The use of analog computers to study hydrodynamic stability is complicated by the fact that the governing differential equation has two rapidly varying solutions (one growing and one decaying), and two which are well behaved. Thus, errors in setting initial conditions and noise in an analog computer excite the rapidly growing solution, making the computer behave in an unstable way. This unstable behavior has its origin in the role played by fluid viscosity. Approximate techniques are discussed whereby these instabilites can be circumvented. The techniques are applied to the case of the Blasius boundary layer on a flat plate, and the results are compared with results available in the literature, obtained with a digital computer. The analog-and digital-computer results are in good agreement.

Closure to “Discussions of ‘The Use of Analog Computers for Determining Surface Parameters Required for Prediction of Thermal Contact Conductance’” (1964, ASME J. Heat Transfer, 86, pp. 550–551)

Closure to “Discussions of ‘The Use of Analog Computers for Determining Surface Parameters Required for Prediction of Thermal Contact Conductance’” (1964, ASME J. Heat Transfer, 86, pp. 550–551)

Static and dynamic control of the basic oxygen process

The limitations of static control techniques for the basic oxygen steelmaking process—such as charge control and static material balances through the use of analog computers—are discussed. The results of laboratory and plant experiments performed by Jones & Laughlin Steel Corp. at their Aliquippa and Cleveland Works—examining dynamic control techniques based on the continuous measurement of CO and CO2 effluent gas evolved from the converter, calculation of the decarburization rate, and, consequently, the development of a continuous carbon balance—are described.

Chemical kinetics in electrochemical processes: Electron transfer between or within multi-component sub-systems of the type:

A general treatment is given for electrochemical processes involving (pseudo-) first-order chemical reactions and semi-infinite planar diffusion. The physical implication of a derived, general equation relating surface concentration and currents — which are time dependent functions — are discussed. The constants of the equation are evaluated for a generalized three-component sub-system, and the formulation of specific response functions is demonstrated for pre-kinetic, post-kinetic, both pre-and post-kinetic, and parallel-kinetic (catalytic) cases. Solutions of the equation are obtained for various specific systems and techniques, including chronopotentiometry, chronoamperometry, and a.c. chronopotentiometry. Also, a general expression for the phase angle (between current and potential) in a.c. methods involving only one pair of electroactive species is developed. Finally, the interpretation, of experimental data is discussed and some methods (including the use of analog computers) which could be used to evaluate the constants of the equation for more complicated systems are mentioned.