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IBM Journal of Research and Development

Issue 1 • Date Jan. 1958

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Displaying Results 1 - 11 of 11
  • Table of Contents

    Page(s): 1
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    Freely Available from IEEE
  • A Learning Machine: Part I

    Page(s): 2 - 13
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Machines would be more useful if they could learn to perform tasks for which they were not given precise methods. Difficulties that attend giving a machine this ability are discussed. It is proposed that the program of a stored-program computer be gradually improved by a learning procedure which tries many programs and chooses, from the instructions that may occupy a given location, the one most often associated with a successful result. An experimental test of this principle is described in detail. Preliminary results, which show limited success, are reported and interpreted. Further results and conclusions will appear in the second part of the paper. View full abstract»

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  • An Error-Sampled Sweep-Position Control System

    Page(s): 14 - 35
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (863 KB)  

    This paper illustrates the application of sampled-data theory to the synthesis of a feedback control system using forward-path digital compensation to achieve high accuracy and fast response. It also presents a detailed description of the design and operation of a transistor system prototype. Developed for the specific purpose of controlling the position of an instantaneous portion of a cathode-ray-tube trace, the system has a number of unusual characteristics such as transport lag, digital integration, and numerous sampling rates. The practical manner in which these characteristics are implemented and the mathematical techniques used for system analysis should prove applicable to a wide variety of control-system problems. View full abstract»

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  • Magnetic-Recording-Head Selection Switch

    Page(s): 36 - 42
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (419 KB)  

    A switch for selecting one out of 100 magnetic recording heads for reading or writing is described. The recording heads are arranged in a 10 by 10 matrix and the switching is accomplished by semiconductor devices. The problem of obtaining suitably fast current rise time during writing is discussed, and the problem of crosstalk from unselected recording heads during reading is analyzed. Experimental results illustrate the performance of the switch. View full abstract»

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  • Computation of Arctan N for −∞ < N < +∞

    Page(s): 43 - 53
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    Rational (R) and polynomial (P) approximations to Arctan N are studied with the aim of computing this function, to any prescribed accuracy and without unduly increasing the number PC of stored constants, in a minimum number M of multiplications (and divisions for R approximations). The number Dg of first correct significant digits in principle is not bounded. The results corresponding to the values 8, 10, 18 and 20 of this number are as follows; (Table of results is given for M ranging in value from 4 to 10.) If M is increased, subroutines with smaller PC are easily deduced from our general results. Thus, for instance, rational approximations with Dg = 6 can be obtained in three multiplications only, if PC = 19 (combination m* = 3, q = 10); but the same accuracy Dg = 6 characterizes also the cases M = 4 with PC = 11 and M = 5 with PC = 7 (combinations m* = 4, q = 6 and m = 5, q = 4). If polynomial approximations are used, Dg = 6 is obtained for M = 5, PC = 7, but also for M = 4 and PC = 11. No subroutines with a stored table of values of Arctan x are considered. View full abstract»

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  • Effects of Low Temperatures on Transistor Characteristics

    Page(s): 54 - 71
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    The four-pole parameters of a group of similar pnp alloy junction transistors were measured in the frequency range from 0.5 to 5 mc and from room temperature down to that of liquid nitrogen. The measured parameters are translated into simple electrical networks for application in these frequency and temperature ranges. View full abstract»

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  • A New Approach to Small-Computer Programming and Control

    Page(s): 72 - 83
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    A novel approach to computer programming and control, used in the IBM 610 computer, allows the solution of complex problems by an operator whose only previous experience with computing has been the desk calculator. The machine's command structure is designed so that the operator can at all times communicate with the computer by a series of short sentence-type instructions closely resembling the steps of manual arithmetic solution. A type of floating-decimal operation called the “auto-point” mode permits entry of data into storage locations with automatic positioning of the decimal point, without elaborate programming. The decimal point is automatically re-positioned during subsequent computation. View full abstract»

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  • IBM Technical Papers Published in Other Journals

    Page(s): 84 - 85
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    Freely Available from IEEE
  • Recent IBM Patents

    Page(s): 86
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    Freely Available from IEEE
  • Authors

    Page(s): 87
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    Freely Available from IEEE
  • Contents of Previous Issues

    Page(s): 88
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    Freely Available from IEEE

Aims & Scope

The IBM Journal of Research and Development is a peer-reviewed technical journal, published bimonthly, which features the work of authors in the science, technology and engineering of information systems.

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Meet Our Editors

Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center