Use Of Digital Computer Research Articles

An estimation theory of level distribution over a long time interval on the basis of the level distribution over a short time interval under a digital measurement of random noise and its experiment

A strictly stationary random process seldom exists in practical random phenomena such as urban noises within a long time interval. Furthermore, noise data within a long time interval has recently been automatically measured in the form of digital level and discrete time. Accordingly, in order to predict and/or estimate the state variables in non-stationary urban noise, it will be necessary to find a skillful method of data analysis by use of digital computer. Concerning the actual road traffic noise with many different types of level distribution forms, at first a new trial of a statistical treatment to estimate the noise level distribution within a long time interval is considered on the basis of any information of the noise level statics (with a high degree of experimental reliability) within a short time interval. The above estimation technique is suitable to the form of digital level and any finite number of data. Finally, the validity of the above estimation theory is experimentally confirmed by applying it to the data of actually measured road traffic noise. The experimental result is in good agreement with the theory.

Generalized equations for the calculation of absorptance, reflectance, and transmittance of a number of parallel surfaces

Derivations of general equations to describe the absorptance, reflectance, and transmittance of any number of parallel surfaces are presented. Two corollaries describing the propagation of light by two surfaces are derived and then used to derive the general equations. These general equations have wide utility because they describe exactly the propagation of light by any number or type of parallel surfaces (interfaces), using relatively simple expressions, which are readily adaptable for digital computer use.

Comparative effectiveness of certain queueing systems with adaptive demand and service mechanisms

This paper sets out to evaluate simple queueing models embodying the concept of adaptation of service to demand and vice versa, systems which hold out the promise of improved operational characteristics by comparison with conventional non-adaptive systems. Over the many years during which research in queueing theory has been in progress there has been little concern with models of this kind, yet it is in the direction of environmental adaptation that one must look for operational improvements. The models studied are mainly of birth and death type. Some consideration is given to renewal models which, in a certain sense, are the equivalents of birth and death types. The emphasis in the paper is placed on the requirements of an operational assessment and on its realization. The use of digital computers in research of this kind is underlined. For illustration extracts from [9] are used to describe the performance of three fundamental adaptive systems.

Verbatim and Whole !

Although I had heard of his prowess with analog com puters and their use for simulation when he was still with Lockheed Aircraft in Burbank, California, I didn't meet Granino Korn until 1956-probably because he had been holed up in a trailer with his wife Terry coauthoring that Bible of early simula tionists, Electronic Analog Computers. After finish ing that book Granino joined the faculty of the University of Arizona as professor of electrical engineering, where he has educated and indoctrinated many fine simulationists. No one, they say, is so fervently dedicated as a convert, and Granino illus trates the point. Some of the most notable contri butions to the use of digital computers for simula tion have been made by that old analog hand with his DARE (Digital Analog REplacement) series of hardware/ software systems. Granino continues to write travel, and lecture internationally - and thus influ ence, for the better I am convinced, the lives and fortunes (?) of all us simulationists.

Controllability, observability and decoupling of multivariable systems

State feedback decoupling theory, as it stands now, is mathematically abstract, in that the system differential equations are manipulated to achieve a one-to-one relationship between the input controls and the output variables. Study of the decoupling problem, however, is greatly simplified by the properties associated with controllability and observability. A now approach towards the development of state feedback decoupling synthesis based on these concepts is presented in this paper. The tangible advantage of this approach i3 the simplification it gives to the systematic use of digital computer for the algebraic calculations, which makes the synthesis procedure very flexible with increase in the dimension of the system

An Application of Digital Computers to Breaker-Fail Protection

The paper describes a technique for detecting changes in power system currents or voltages. The technique is based upon the calculation of the rate of rise of these quantities at their own zero crossings and is referred to as “current (or voltage) derivative relaying”.The technique emerged from a study of the possible use of digital computers for back-up protection when it is used to detect the failure of a circuit breaker to interrupt the flow of fault current.The technique is found to be suitable also for realisation as a relatively simple electronic circuit.

Software Engineering Education

Recent trends have led to the expanded use of digital computers in large complex system applications. The major burden of meeting the requirements for these systems has fallen on the flexibility of software. This has placed many demands on all areas associated with digital systems development. A significant impact has been on the development of software personnel required to develop and manage these complex systems. The purpose of this paper is to present a three level program for software education of executives, managers, and engineers which is being offered at the Air Force Institute of Technology (AFIT). The needs and approaches in satisfying software engineering education requirements are presented. Educational objectives for executives, managers, and engineers serve as the foundation of the curricula, courses, and topics presented.

Studies on packing of powder. VII. The use of digital computer for simulation of powder compaction on two-dimensional model (author's transl)

Following the previous work on a simulation of powder compaction on two-dimensional model, where 400 discs were used and the cohesion probability P' and insertion probability P" were introduced, 1600 discs (40×40) were used and it was assumed that discs did not shift to the hole present in the lower layer when the coordination number of a disc or the probability variable (R) related to the coordination number was greater than a given value (q). The elimination or jumping probability P'" were newly introduced. Almost all the data of porosity and tapping number followed the first-order rate equation and the rate constant k increased with decreasing the probability P' and with increasing the probability P". As the tapping number increased, the porosity approached a definite value, which varied according to the magnitude of the values of q and P"'.

Digital computer applications in the control of electric power systems

This paper reviews the state of development of the use of digital computers for the control of power systems. The discussion of control functions which are currently in service in the electric power industry is made within the framework of computer hierarchies and from the viewpoint of overall power system operation.

Application of Ultrasound to NDE of Materials

Absrract-A review of state of the art applications of ultrasonics to the nondestructive inspection of materials for defects is given along with some of the limitations associated with the present state of the art. These limitations include 1) the inability to determine defect dimensions quantitatively, 2) the lack of suitable reference standards, 3) the general lack of equipment for the inspection of parts with complex geometries, 4) the nonreproducibility of transducer characteristics, and 5) the lack of a sound theoretical foundation for ultrasounddiscontinuity interaction. Some of the current research and development work in the use of digital computers for scanning parts with complex geometries and in signal processing to increase inspection reliability and defect detection is also described.

Automation in Metal Processing: A Review

The iron and steel industry is characterized by the enormous size of its production processes and machinery and by ever-increasing requirements of precision and accuracy on its steel products. Automation through the use of digital computers has been a significant factor in increasing unit production per process and per plant. In addition, computer software has become a principal part of the technology of metallurgical processes. For example, on strip and plate mills, near optimal interactive control programs involve value trade-offs amongst product qualities, including flatness or crown, thickness, width, grain growth and tensile characteristics, and the more conventional values of yield and tonnage.

Monochrome digital image enhancement

The use of digital computers as an aid in the enhancement of monochrome imagery is explored. Point processes, spatial processes, and artifact generation are discussed. The former includes single pixel nonlinear mappings for better visual response. Spatial processes include both linear and nonlinear filtering techniques in the Fourier and singular value decomposition domains of an image. Finally, the generation of possible artifacts by enhancement processes is discussed. Numerous pictorial examples illustrating all the techniques developed are included throughout the paper.

Self-Organizing Control and Applications to Trainable Manipulators and Learning Prostheses

Self-Organizing Control (S.O.C.) has been defined as the descriptive which treats dynamic systems with uncertainties operating in deterministic or stochastic environments. Self-organization is performed by the controller to on-line reduce the uncertainties pertaining to the behavior of the systems and to drive its output to attain the desired goal. Parameter Adaptive S. O. Controls explicitly identify the uncertainties of the system dynamics, which are characterized by a parameter vector, while Performance Adaptive S. O. Controls improve the uncertainties that pertain only to the improvement of its performance, and therefore, identify the systems implicitly. A collection of successful methods for both Parameter Adaptive and Performance Adaptive Algorithms are discussed and compared in this paper to demonstrate the desirability and applicability of explicit or implicit parameter identification in a SOC system. The implementations of these algorithms requires the use of digital computers of various sizes depending on their specific application at hand. An interesting application of S. O. Control to trainable industrial manipulators and learning prosthetic devises, using minimcomputers is currently investigated by the author. Parameter Adaptive schemes, using explicit parameter identification of the system dynamics for an “attitude control” type of hierarchical arm-joint coordination seems more appropriate for training industrial manipulators to perform mechanical tasks. On the other hand, Performance Adaptive techniques are more suitable for human prosthetic devices with learning capabilities, controlled from the nervous or muscular system of the computer with visual feedback, to perform purely anthropomorphic functions. Current results of this investigation will be discussed.

Multi-Company Electric Power System Control on the Pennsylvania-New Jersey-Maryland Interconnection

A presentation in five sections describing the use of digital computers for generation and transmission control employed by eleven electric power companies operated as a fully coordinated power pool. The theme section provides the introductory description of the power pool and an overview of the objectives and responsibilities of the pool and the participating member companies. The companion sections describe unique approaches taken by four of the member companies. The pool computer control center has been in service since 1970. Two of the company control systems were placed in service in 1973, one in 1974, and the fourth is scheduled for operation in 1976. Each presents a solution tailored to satisfy the requirements of an independent corporate entity and the responsibilities as a member of the multi-company coordinated power pool operation.

A time-share based simulator to teach the use of digital computers

A course to acquaint students with the laboratory based digital computer as a chemical tool.

Computer Applications in Urban Water Distribution System Control

The objective of water distribution system control is to provide an adequate level of service at all points in the system economically under varying conditions of loading. With the increase in size and complexity of water systems, the need for reliable and economic operation has resulted in the use of digital computers for data acquisition and supervisory control. In this paper, the functional aspects of computer control of water systems are discussed with respect to (i) alternative system configurations for reliability and cost, and (ii) the application of mathematical models for simulation and optimization of the distribution system operation. Both on-line and off-line software requirements for computer control are discussed. Finally, examples of applications of recent developments in computer control are given together with directions for future research effort.

The Transformation of Aerodynamic Stability Derivatives by Symbolic Mathematical Computation

SummaryThe formulation of mathematical models of aeronautical systems for simulation or other purposes, involves the transformation of aerodynamic stability derivatives. It is shown that these derivatives transform like the components of a second order tensor having one index of covariance and one index of contravariance. Moreover, due to the equivalence of covariant and contravariant transformations in orthogonal Cartesian systems of coordinates, the transformations can be treated as doubly covariant or doubly contravariant, if this simplifies the formulation. It is shown that the tensor properties of these derivatives can be used to facilitate their transformation by symbolic mathematical computation, and the use of digital computers equipped with formula manipulation compilers. When the tensor transformations are mechanised in the manner described, man-hours are saved and the errors to which human operators are prone can be avoided.

Dynamic Analysis of Multistory Buildings

Analysis and design of common types of buildings to resist earthquake forces is done by the method described in the Uniform Building Code. Approximate formulas for natural periods of fundamental mode of buildings are available and are used in the static method of aseismic design of Uniform Building Code. However, some building codes in the seismic regions require dynamic analysis of tall buildings and other important structures. The dynamic analysis of multistory structures is laborious and time consuming because of the many degrees of freedom involved. Modern electronic computers have made possible the dynamic analysis of multidegree freedom systems which was prohibitive by hand calculations. However, when the number of degrees of freedom is large, the dynamic analysis requires the use of digital computers of large capacities and the computer time used can be very expensive. In the modal method of dynamic analysis, the natural periods and mode shapes for various modes of vibrations are determined by computer analysis. The objective in this paper is to develop simplified methods for determining natural periods of vibrations of multistory buildings so that expensive computer time is kept to a minimum. Since the aseismic design by dynamic analysis require a few preliminary trials before final satisfactory design is achieved, the simplified methods can save laborious computer calculations in the preliminary design. The simplified methods discussed in this paper are developed using the concept of an elastic shear wave equation in solid uniform bars. A numerical example is presented to compare the simplified methods with the more rigorous analysis.

The Use of Digital Computers in Dermatologic Diagnosis: Computer-Aided Diagnosis of Febrile Illness with Eruption

A computer program has been written to assist medical personnel in the diagnosis of eruptions with fever. Thirty-four criteria are utilized in the diagnosis of 33 clinical entities. Diagnosis is based on template analysis, Bayesian statistical analysis, or a combination of the two. Of 97 cases of febrile illnesses with eruption, 62 were documented diagnoses within the universe of the program. Template analysis succeeded in 90% of these, Bayesian analysis produced the correct diagnosis in 81%, and in 55% it resulted in a list containing the clinician's diagnosis is most probable. The combined method yielded the clinician's diagnosis as most probable in 65% of the cases. The discrepancies between the clinician's diagnosis and the computer output have been analyzed and found to be due to inadequacies in the dermatologic data base.

The use of a small digital computer for stereotactic surgery.

There are many stereotactic systems available for the direction of fine surgical instruments into the deeply situated nuclei of the brain. In some of these techniques the location of the target and the calculation of the corresponding settings on the stereotactic frame are determined by approximate two-dimensional solutions. In others, careful alignment of the axes of the stereotactic frame with the mid-plane of the brain can simplify complicated three-dimensional mathematics to two-dimensional problems. The use of digital computers to calculate accurate frame settings to reach chosen targets in the brain is an obvious but expensive way of eliminating the need for time consuming alignment procedures.