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The history of digital computers represents a twofold development toward the common goal of harnessing “electronic energy” to solve human problems. On the one hand we have the hardware designers producing faster, cheaper, more versatile computers to execute larger, more complex programs. On the other hand we have the software designers generally producing faster, cheaper, and more versatile languages, compilers, operating systems, and application software with which to program these larger, more complex problems. It is only recently that timesharing and interactive systems have begun to bridge the hardware-software generation gap. This paper describes a system which is intended to eliminate the gap by providing a computer which directly executes a powerful language - APL - in a highly efficient manner. The programmer and machine communicate entirely in APL with a fully interactive timesharing operating system integral in the design. In particular this paper focuses on the execution aspects of the computer and relates results obtained by emulating the main processor to conventional computer approaches.

This paper surveys record automatic optimization methods which either have found or should find useful application in the optimal design of microwave networks by digital computer. Emphasis is given to formulations and methods which can be implemented in situations when the classical synthesis approach (analytic or numerical) is inappropriate. Objectives for network optimization are formulated including minimax and least pth. Detailed consideration is given to methods of dealing with parameter and response constraints by means of transformations or penalties. In particular, the formulation of problems in terms of inequality constraints and their solution by sequential unconstrained minimization is discussed. Several one-dimensional and multidimensional minimization strategies are summarized in a tutorial manner. Included are Fibonacci and Golden Section search, interpolation methods, pattern search, Rosenbrock's method, Powell's method, simplex methods, and the Newton-Raphson, Fletcher-Powell, and least squares methods. Relevant examples of interest to microwave circuit designers illustrating the application of computer-aided optimization techniques are presented. The paper also includes a classified list of references.

1. Introduction. The purpose of this article is to present a revised version of an early paper by the author on a register transfer, logic design language and its application to the design of early microprogrammable computer. This paper [1] as an invited paper at an IRE was presented originally at an IEEE meeting held at the Moore School of the University of Pennsylvania, early in 1957. It is being published here in the open literature for the first time in order to present to a wider audience this approach to computer design in its original form.

In setting the stage for the papers which follow, there is discussion in this paper of some problems of terminology concerning multiple-access, on-line, interactive man-computer systems. It presents three viewpoints from which to examine man-computer interaction.

The application of electromechanical mass storage devices to computers is rapidly increasing in importance. Mass storage units are being assigned key general systems functions and are basic to many developing applications such as time sharing, communication, and on-line processing. In this paper, the characteristics of typically available hardware in the drum, disk-file, and tape-strip categories are discussed. Next, the most important applications of mass storage devices are reviewed. The special considerations in the design of computer systems which use mass storage are outlined. Commonly used and certain important proposed techniques of file organization and processing are then described. The paper concludes with a discussion of the technology used, some aspects of control unit design, and future possibilities in both hardware and software. Major challenges to designers of future hardware are identified as reduction of the cost per bit of removable media, economical devices with storage capacities larger than 109bits, and a solution to the dilemma of increasing access time with increasing storage capacity.

This paper discusses the ILLIAC IV computer and its application to seismic signal-processing problems. ILLIAC IV, now being fabricated by the Burroughs Corporation, will be operational at the University of Illinois' Computer Science Department in 1970. ILLIAC IV is an array of 256 coupled high-speed digital computers; as such, it has the capacity to execute algorithms 256 times faster than present-day computers. Achievement of large speedup factors, however, is dependent upon "structuring" an algorithm into groups of (nominally, 256) identical computations. As an aid to the programmer, the Tranquil language is being designed with certain common statements, such as matrix operations, prestructured to provide for the parallel execution of code on many pieces of data. These, as well as other aspects of the ILLIAC IV system and the Tranquil language, are described in the first part of this paper. The second part of the paper discusses the structuring of common signal-processing algorithms, such as beam forming, convolution, and fast Fourier transform for ILLIAC IV parallel computation. It is shown that, in a great variety of situations, the full speedup factor, 256, can be obtained.

A comprehensive technical survey of Soviet switching theory and its applications to the logical design of digital systems reveals that, despite considerable activity (763 papers and books), the average state of the art in the U.S.S.R. is somewhat behind that in the U.S. However, there are a large number of noteworthy contributions, particularly in those aspects of the field dealing with complexity estimates of switching networks, synthesis of multiterminal circuits, the selection of logical primitives (building blocks), and certain minimization problems. This paper evaluates the Soviet position through June, 1964, compares it with that in the West, and summarizes the significant Soviet technical contributions. Recommendations are offered for initiating research in the United States in several special problem areas in switching theory.

During the past two years development has been initiated on several large-scale automatic digital computing machines, both in this country and abroad. The present paper is concerned with the over-all organization of one such machine. A logical division of the machine into four major components is described, and the machine performance is interpreted in terms of these component functions. The electronic techniques used to accomplish the storage, transmission, and arithmetic manipulation of numbers, together with certain methods used for control of the computer, are briefly discussed. Although the paper is concerned with the design of a particular machine, it is felt that the design problems and engineering techniques are applicable to most large-scale computing machines.

This paper describes the application of reliability calculation techniques presented in a companion paper [1] to actual power system networks. A digital computer program to facilitate reliability calculations is described, and a comparison of calculated and observed reliability on an actual system is presented.

Many papers have been written about the reflected binary system and it is well known in the computer field for analog-to-digital conversion. The method used in creating this system may be extended to systems of bases other than two. It is the purpose of this paper to carry this extension to its logical conclusion. The author describes how reflected systems of different bases may be composed. The equations for translating between the conventional and reflected systems are then derived. It is also demonstrated how the reflected binary system is a special case of reflected number systems and how the general case simplifies for the reflected binary case.

This paper discusses various strategies and techniques used for editing two-dimensional programs or text and for automatic type-composition of conventional mathematical expressions. The techniques may be used for input prepared on a typewriter that is on-line to a computer or that generates off-line machine-sensible documentation, such as punched paper tape. These techniques, with minor modification, may also be used with a keyboard-controlled cathode ray tube as an input device. Methods of driving a special typewriter in the preparation of composed text can be extended for photocomposition or for a high-speed printer with a special character set. The basic algorithms for the regeneration and internal storage of the two-dimensional document, input in an arbitrary character-by-character order, are discussed, as are other basic techniques for recognizing and parsing two-dimensional mathematical forms and symbols. Illustrations show applications to the automatic composition of mathematical tables and to computer-assisted typing of mathematical text using a newly-designed typewriter terminal (see Fig. 8 of text).

Obtaining a cost-effective teleprocessing network is postulated on efficient utilization of the communication links and processing equipment. A variety of line-sharing devices and procedures are commonly used for this purpose. The functional, economic, and application aspects of frequency-division multiplexing (FDM), synchronous time-division multiplexing (STDM), asynchronous time-division multiplexing (ATDM), message switching concentration (MSC), and line (or circuit) switching techniques are discussed. The motivations for line sharing stem from economies of scale in the cost of bandwidth and from the traffic smoothing effect which such devices produce when serving a large terminal population characterized by unscheduled requests for service. The discussion of these techniques includes a detailed contrast between multiplexing and concentration, two terms which are often (and unfortunately) used synonymously. It is shown that FDM and STDM are examples of conventional multiplexing, whereas message switching and line switching usually illustrate concentration. ATDM is shown to be a hybrid line-sharing scheme embodying certain features of both concepts. Thus it is often referred to as statistical multiplexing. The first part of the paper is devoted to a functional explanation of the various concepts referenced above. The balance of the paper is concerned with applications and systems-design considerations involving multiplexing and concentration techniques. The application section focuses on important economic factors pertaining to the selection and use of the various methods. The role of line-sharing devices in contemporary common-carrier and end-user networks is also considered. The economic and technical aspects of these contrasting application environments are emphasized and illustrate the multiplicity of uses for line-sharing devices. The concluding portion of the paper includes a discussion of system-design considerations. This section illustrates precisely how the decision to use multiplexers or concentrators in a typical computer-communication network is implemented. Various techniques for geographically positioning multiplexers and concentrators to minimize total costs are presented. The use of one of these procedures is demonstrated using a typical design problem as a case study.

Project Whirlwind is a high-speed computer activity sponsored at the Digital Computer Laboratory, formerly a part of the Servomechanisms Laboratory, of the Massachusetts Institute of Technology (MIT) by the US Office of Naval Research (ONR) and the United States Air Force. The project began in 1945 with the assignment of building a highquality real-time aircraft simulator. Historically, the project has always been primarily interested in the fields of real-time simulation and control; but since about the beginning of 1947 most of its efforts have been devoted to the design and construction of the, digital computer known as Whirlwind I (WWI). This computer has been in operation for about 1 year and an increasing proportion of project effort now is going into application studies. Whirlwind I was designed for use in control and simulation work such as air traffic control, industrial process control, and aircraft simulation. Various design and synthesis issues are presented. [Note: Discussion of this paper was combined with that of the following paper: "Evaluation of the Engineering Aspects of Whirlwind I."]

The paper reports on augmenting human problem solving capability in the day-to-day work in management or science through provision of information in a large integrated file with split second response to demands for data or program execution. A number of such systems have been developed. However, the description is in terms of the latest system developed at the University of Pennsylvania. In the first part, the paper deals with tbe Multilist technique for mass storage embedded in a system for remote consoles. Console services, a high level query language and interpreter for the query language, and a highly structured file organization are among the special subsystems described. The second part is devoted to illustrations of usages describing a number of the applications which can be concurrently serviced within the system. These include: an automatic library catalog, to illustrate storage and retrieval functions, and inventory management, to illustrate large scale management functions.

Automatic interpretation of electrocardiograms is a particular example of the application of digital computers to medical diagnosis; this paper describes our experience with a new approach involving pattern recognition techniques. The program employs a multiple adaptive matched filter system with a variety of normalization, weighting, comparison, decision, modification, and adapting operations. The flexibility of the method has permitted study of effects of experimental variations of these operations on the pattern classification process to simulate human interpretation of electrocardiograms more closely. These programs have been successfully applied to actual electrocardiograms from cardiac patients. These researches in application of computer pattern recognition techniques to the automatic interpretation of electrocardiograms have been undertaken because they join together three fields of great interest. First, an example of artificial intelligence or a self-organized system is represented by the adaptive filter memory, together with the related decision operations. Second, we consider our program to be a model of complex sensory discrimination and use our intuition of human psychology as a guide when selecting one of several possible program mechanisms to overcome temporary obstacles. Third, the automation of medical diagnosis is a rapidly developing and promising field contributing to medical progress. This paper pays particular attention to the third of these objectives. The present state of computer analysis of electrocardiograms is mainly one of orthogonalization of the spatial vector, point recognition to separate the various component waves, parameterization, in one case via Fourier techniques, and then statistical matrix analysis.

An important objective of software test programs is to identity, "high-risk" components. This paper focuses on one method which can be applied to identify high-risk software components, the use of a classification tree with an established software metrics set. The selected examples of high-risk software components are those modules which are most likely to induce errors in the target operational system, and those software components which will require the most effort in the development process. The associated metrics are software reliability and productivity. This paper describes the methodology utilized by the US Army in the application of classification trees for analysis of software metrics data. A detailed example is provided with a step-by-step procedure for construction of a classification tree for software metrics analysis. >

This paper reviews the state of the art of methods and techniques suitable for use in the automatic optimization of microwave circuits by digital computer. A number of significant recent developments in the rapidly developing area of computer-oriented circuit theory and design which may be directly applied to high frequency or distributed circuits are emphasized. A fairly extensive classified bibliography on optimization methods and on some applications, primarily in the microwave area, is included. The principal aim of this paper is to bring the microwave circuit designer up to date with developments in computer-oriented optimization methods and techniques and their application to microwave circuit design. To achieve this, the state of the art is reviewed in a tutorial manner, highlighting the talk with material taken from a variety of recent research papers, published during the last year or so. Promising areas for future work are indicated. A fairly extensive classified bibliography on optimization methods and on some applications, primarily in the microwave area, concludes the paper. Papers and books not necessarily in the microwave area are referenced if it is felt that the subject matter is, nevertheless, relevant. The first question that a microwave circuit designer might have is what material should he read to convince himself that he can solve a wide variety of design problems using optimization techniques. Five articles [1]-[5] are referenced under the heading of Reviews of Network Optimization which should probably be found most useful.

This paper presents a synthesis method of ternary digital systems by means of a threshold algebra. The method is based on the fact that the K operations of any ternary function can be expressed as threshold operations on a set of functions called midterms. Such midterms can be easily generated from the outputs of the ternary multivibrators described by the authors in a previous paper [4].

Applications of computers in the planning of power system generation, transmission, and distribution are surveyed. Following a brief description of significant developments in the growth of these applications over the 22 years since the first published paper, the stages in planning (policy, standardization, outline, and detail design) and the mathematical techniques which can be applied to the numerical solution of quantifiable problems arising in these stages are outlined. The greatest concern is with the technical and economic studies commonly used in the major areas of planning, i.e., load forecasting, assessment of generation capacity and mix, transmission and distribution network development. Approaches using simulation and optimization techniques are described. Reference is made to developments in corporate planning.

In this paper we discuss the issues involved in implementing an automatic computer voice response system which is capable of serving up to ten independent output channels in real time. The system has been implemented on a Data General NOVA- 800 minicomputer. Individual isolated words and phrases are coded at a rate of 24 000 bits/s using a hardware adaptive, differential pulse-code modulation (ADPCM) coder, and stored on a fixed-head disk as a random access vocabulary. By exploiting the features of ADPCM coding, it is possible to create and edit automatically a vocabulary for the system from an analog tape recording of the spoken entries, with minimal operator intervention. To provide ten simultaneous output lines of speech which are independent of each other required the use of an efficient scheduling algorithm. Such an algorithm was provided by the computer manufacturer in their real-time multitasking system which was part of their Fortran software. Thus almost all the programming required to implement this real-time system was in Fortran, thereby providing flexibility and ease in making changes in the system. Initial applications of the voice response system are in computer aided voice wiring, automatic directory assistance, and experiments on speaker verification, but the system is sufficiently modular to adapt readily to other applications.

The main objective of this paper is to give a survey of recent automatic optimization methods which either have found or should find useful application in the area of computer-aided network design. Huang's family of algorithms for unconstrained optimization is reviewed. The Fletcher method and the Charalambous family of algorithms for unconstrained optimization, which abandon the "full linear search," are presented. Special emphasis is devoted to algorithms by Bandler and Charalambous on least pth and minimax optimization which can be readily programmed and used. Due to work by Bandler and Charalambous, it is shown how constrained minimax problems can be solved exactly as unconstrained minimax problems by using a new approach to nonlinear programming. The application of minirnax optimization on the design of lumped-distributed active filters, problems for future investigation, and a select list of references are also included.

In this computer era, most engineers have benefitted tremendously from use of computers. This paper explains the application of computer-aided design to the remote control transmitter for the Magnavox deluxe color T. V. remote control system.

A historical development of mechanical and electronic differential analyzers as well as the significant developments in simulation techniques are discussed. Present-day application of modern analog and hybrid computers to electric power systems are presented. Included are the simulation of electric machines, static converter drives, transmission lines, and dc power systems. Special-purpose analog and hybrid computers are also discussed briefly. The material presented in this paper should enable an informed evaluation of the capabilities of analog and hybrid computers in the analysis of power system problems.

This paper claims that the increasing heterogeneity of the community of conmputer users poses a challenge to psychologists and human factors researchers. There follows a brief discussion of why this challenge apparently has not yet evoked a strong response. Three problems, or problem areas, are identified as being particularly in need of human factors research. These are (1) the development and evaluation of conversational languages, (2) the determination of how the use patterns adopted by users depend on system characteristics, and (3) the description, or modelling, of man-computer interaction.

Computer-driven cathode-ray tube (CRT) displays are becoming an important means of on-line man-machine communication, particularly for graphical input/output in laboratory investigations of computer-aided design techniques. Their operation, however, often requires so much of the computational resources of the associated computer that they are not yet considered economic or practical for general industrial use. This paper discusses the systems engineering problems in designing and using display systems, with emphasis on the hardware-software tradeoffs. As an example, a display specifically developed for computer-aided design applications is described which has unusual special-purpose computing capabilities for dynamic picture manipulations, including rotation, scaling, and translation of 3-dimensional images. it is concluded that there is much work ahead, and that the proper hardware-software organization for these complexes of computers, communication links, terminals, and men is a fertile field for the systems engineer.

The study of speech communication and speech processing systems by simulation on a digital computer, and the design and physical implementation of these systems with discrete components, require a detailed knowledge of the elements known as digital filters. Following a definition of the digital filter, the different areas in which digital filters have been used in speech research and communication are explored. The basic theory relating to the design and application of digital filters is reviewed. Attention is given not only to the use of a general purpose computer to mechanize the simulation but also to the design of special purpose hardware to realize the digital filter as either an actual communication system component or as a laboratory research element. Following a discussion of several of the numerical problems that can arise in the design and utilization of digital filters, the paper concludes with a cursory look at some of the advantages and disadvantages of the use of digital filters in speech processing systems.

General Purpose Digital Computers are now making their appearance in industrial plants. For the most part, they do not merely mechanize tasks previously handled by humans but make possible an entirely new era in control of complicated processes. Industrial Control Computers are now being designed for such applications. This paper discusses in basic terms the characteristics and performance features of Industrial Computers, and how they can increase process profitability. Computer Speed, Memory Capacity, Kind of Memory, Mechanical Design, Programming Features, Reliability and other specifications are related to requirements of Industrial Control. A typical application analysis is explained through use of a high-speed tin plate line as an illustrative example. Several suggestions are offered as an aid in the writing of better purchase specifications. Currently about three years are needed to go from first conception to an operating Industrial Computer installation. A discussion is given of the many tasks to be completed by user and supplier in this process.

This paper presents a procedure for stability analysis by the Tsypkin Locus method of an unforced control system with relay-type actuator. The procedure was written with special attention given to the minimization of the computation time; thus it may be efficiently executed on a minicomputer. The procedure and a flow chart are presented and the case of a nuclear reactor control is given as an example.

This paper is a summary of the principal conclusions that can be made from a rather extensive survey of the open Soviet literature in the technical areas relevant to the design of reliable digital computers. Particular emphasis in the survey was on the various techniques for the constructive application of redundancy in order to achieve the reliability necessary for the successful realization of machines of high computational power and high availability. In this summary overall conclusions are presented regarding the nature and significance of Soviet activities in these fields.1

Displays are playing an increasingly important role in providing man-machine interaction in computer systems. Small-screen displays, such as cathode-ray tubes, coupled with alphanumeric or graphic input devices, provide a console that permits close on-line interaction between the user and the computer and data base. Large-screen displays permit groups of users to interact both with one another and with the information processing system. This paper discusses several of the more important applications of computer generated displays, display systems design and characteristics, and display technologies which are the primary candidates for implementing the visual transducer portion of future display systems. Several problem areas are identified.

Digital computers have had a significant effect on engineering practice, but they have not yet had a comparable effect on educational methods, primarily because of a lack of convenient man-machine communication capabilities. However, during recent years substantial strides have been taken in making the digital computer more responsive and easier to use with natural "problem-oriented" languages and almost instantaneous response. This emerging generation of rapid-access computer systems promises to have a profound impact on both engineering practice and education. The purpose of this paper is to describe an educational experiment that was undertaken to explore the use of "computer laboratory" projects as part of a graduate course on "Electronic Circuit Theory: Nonlinear and Time-Varying."

This paper describes the functional characteristics of the Standard Computer MLP-900 processor. This microprogrammable processor is designed for general-purpose emulation of a wide variety of known processors as well as being adaptable to new general-purpose and special-purpose applications. Two approaches to the design of microprogrammed processors, namely minimally encoded and highly encoded, are considered. The significant architectural properties that provide the multilingual capability are discussed. A target language-execution strategy for the MLP-900 is presented followed by a problem-oriented target instruction set which provides for packed field operations. Finally, some projected uses of the processor are considered.

Computers are used in medicine to assist with the two related tasks of increasing diagnostic precision and of making the improved diagnoses more widely available. Following a brief review of the background of computer-aided medical diagnosis, this paper describes the various automated diagnostic methods and their mathematical bases. The efficacies of several diagnostic procedures are compared. The important matter of the quality of the medical input data is discussed. It is pointed out that, to achieve the goal of wide-spread computer-aided diagnosis it is necessary not only to strengthen medical computing capabilities but also to educate physicians to the advantages of computer diagnosis.

The weighing industry is perhaps more cognizant of accuracy than any other instrumentation industry. Basic scale accuracies of 1/10 of 1 per cent are, generally speaking, minimum, with over-all system accuracies in this vicinity desirable. The two digital devices described in this paper are unique in that they are an integral part of the weighing instrument and as a result, the accuracy of conversion from weight indication to a digital signal is absolute (no error encountered). Therefore, the system accuracy is virtually the some as the basic instrument accuracy.

This paper explores various factors to be considered in the application of computer techniques to radio engineering functions. A general outline of the radio engineer functions related to system performance, layout engineering, frequency coordination, and administration are included. The interrelationship of the decision parameters of manpower, economics, work volume, work complexity, and computer development are discussed. Consideration is given to the productivity and economic aspects of computer application. Some potential problem areas are reviewed.

A system of IBM 7090 Data Processing System computer programs was developed for the purpose of normal and/or fault simulation of the Saturn computer. This paper will describe the design of the simulator and cite several applications in the development of the Saturn computer. The architecture, plus several important characteristics of the simulator, are presented. These include the Design Automation input interface, the logic selection procedure, failure injection, the compilation procedure, logical simulation and functional simulation. The ability to simulate up to 4000 Saturn instructions in either normal and/or fault environments (up to 33 faults per IBM 7090 run) will be demonstrated. Simulation of single, multiple, solid or intermittent faults, plus an automated statistical analysis of intermittent fault simulation results, will be presented. The IBM 7090 execution time of a compiled logic simulator can be prohibitive. To minimize running time several programming techniques were utilized, including logic block ordering (to allow single pass simulation), parallel fault simulation, stimulus bypassing, and functional simulation. These techniques are described. Several special forms of simulator output were developed. The use of this output and the applications of the simulator are presented, including design verfication, test program evaluation, generation of a test point catalog, disagreement detector network evaluation, disagreement detector placement, intermittent failure analysis.

This paper is intended to show how the unique features of the Variable Instruction Computer (VIC) make it valuable for applications requiring high reliability. By careful choice of components, use of error-checking circuits, and selected application of redundant hardware, the basic unextended reliability of the VIC is comparable with the state-of-the-art. This is verified by a standard MIL-HDBK-217 type of analysis. The variable instruction technique is briefly described by use of a block diagram. The method for extending reliability by use of variable instructions is explained and an example is given. The concept of algorithm change to achieve controlled graceful degradation is discussed. An analysis of a typical application of this technique is given and extensions of the variable instruction concept to more advanced reliability requirements are discussed.

Considerations of bandwidth, noise, distance, response time, data and system integrity, maintenance, interfacing, software control, data organization, cost, and development time complicate the implementation of intercomputer links in real time control and data acquisition systems. This paper tells how to do it. The NAL link provides an example.

This paper describes the system organization of a digital computer whose purpose is to activate simultaneously more than one cockpit of an operational flight trainer. The simulated aircraft are assumed to be all of the same type, but each is simulated independently. The computer is drum-sequenced and represents an application of the theory of multiple computers, since there are several different kinds of memories and more than one arithmetic unit in the system.

This paper proposes a method for the statistical evaluation of small subsystems performance. The method requires that performance data from a small subsystem be analyzed using a multiple linear regression method; this has been programmed for a digital computer making use of a step-wise solution. The result along with predetermined component variation is then used in a computer programmed Monte Carlo simulation to develop both the output distribution and descriptive statistics. Experimental results from a small, one-core impulse-switched memory system are presented. Other applications include the analysis of high speed computer circuits; one application integrated circuitry, offers great promise.

The essence of decision-making is understanding the economic impact of uncertainty. In this paper a previous discussion of information value theory is extended to illustrate how the availability of information on the uncertain factors of a problem affects the probability density function of profit, the profit lottery. A bidding problem serves to demonstrate the type of calculations required and their implications.

The algorithm described in this paper is the outcome of an endeavor to answer the following question: Is it possible to find procedures which would enable a computer to solve efficiently path-connection problems inherent in logical drawing, wiring diagramming, and optimal route finding? The results are highly encouraging. Within our framework, we are able to solve the following types of problems: 1) To find a path between two points so that it crosses the least number of existing paths. 2) To find a path between two points so that it avoids as much as possible preset obstacles such as edges. 3) To find a path between two points so that the path is optimal with respect to several properties; for example, a path which is not only one of those which cross the fewest number of existing paths, but, among these, is also one of the shortest. The minimal-distance solution has been programmed on an IBM 704 computer, and a number of illustrations are presented. The class of problems solvable by our algorithm is given in a theorem in Section III. A byproduct of this algorithm is a somewhat remote, but unexpected, relation to physical optics. This is discussed in Section VI.

Physical elements used for switching logic have finite probability of failure. The application of redundancy to logic circuits is presented for improving computer reliability. This paper shows various redundant configurations considered and the conclusionon drawn. From all of the considerations, the majority gate provides a practical method for increasing the reliability. It shows that for operating periods which are short compared to the mean time to failure of the elements, a substantial increase in system reliability is obtained with majority-gate redundancy.

Performance calculations on single-phase induction motors require two to four times as much time as comparable calculations on polyphase motors. This paper describes MONECA, a new calculator developed especially for these calculations. It is based upon a new revolving-field equivalent circuit, but can be readily reconnected for many other different circuits. It has shortened the time for many present calculations, made practicable many calculations that were formerly too time-consuming, and has given its users a clearer concept of the revolving-field theory. It appears to have an almost unlimited number of future applications.

The accuracy of a digital filter is limited by the finite word length used in its implementation. Techniques have been developed to analyze this problem. Good agreement between the theoretical and experimental results has been reported. This paper discusses some of these accuracy problems and reviews some of the approaches used in investigating them. The calculation of the statistical mean-squared error at the output of the filter is discussed in detail.

This paper describes the planning and execution of a recent experiment which utilized a hardware monitor- ing device and associated analysis programs to evaluate the performance of a computer system which is employed for real-time satellite command and control. The evaluated system was the portion of the United States Air Force Satellite Control Facility Real-Time Data System, located in Sunnyvale, California. Communication line, processor, and channel utilization were analyzed, as was the interaction of Executive, Input/Output, and Application software modules.

Techniques in automated data-handling for medical research and patient-care purposes are being investigated using a conversational timeshared computer system. This paper covers the initial design considerations, implementation experience, and user reaction with the prototype set of on-line, multiple-access, general-purpose information storage and retrieval programs. This system is designed to pemit hospital personnel (without the need for special assistance or any direct intervention by trained computer programmers) to define and establish private data files, to enter or change moderately large volumes of English text or coded data, and to retrieve and manipulate selected output information. Hospital staffs, from remote terminals, have been using this system on an operational basis for more than a year. The development and implementation of the system is being carried out by Bolt Beranek and Newman Inc., and the Massachusetts General Hospital, under the support of the National Institutes of Health.

This paper describes methods for using power system readings to compute a real-time power flow solution of the transmission network. The use of redundant data is discussed and procedures are outlined to detect, identify, and correct for data errors. Several examples are presented and the numerical behavior of the methods is discussed.