Showing papers by "Mitre Corporation published in 1970"

Diffraction-Limited Scalar Image Formation with Holograms of Arbitrary Shape

Abstract: A theory of image formation is presented for a large-angle, point reference hologram, whose recording arrangement consists of a surface of arbitrary shape, a point reference source, and the object. The hologram is illuminated by a spherical wave during reconstruction. The resulting image field is similar to that of a Fourier-transform hologram. An exact, integral formulation of monochromatic, scalar diffraction theory is used to find the image field. The hologram is modeled by surface sources determined from the irradiance of the recorded field. The image field produced by the holographic system approximates the field produced by the ideal system, which forms the image of a point object by launching a converging, spherical wave.

Optimal Inventory Policies in Perturbed Demand Models

Abstract: Investigation is continued of inventory models in which customer good will is lost when stockout occurs. Several models are formulated and optimal policies for the firm are derived conceptually i.e., algebraic equations satisfied by the optimal parameter values are determined. Both constant and distributed demand are considered, and it is shown that the same formulation applies to both.

Braille display device

Abstract: In the Braille display system disclosed herein a plurality of identical cells are arranged in a row and each cell is adapted to display a single Braille character. Each cell employs a plurality of pins which can be selectively raised to projecting positions by pneumatic signals which are common to all of the cells in a given row. Further, each cell includes an electrically actuable interposer member which can be selectively operated to either lock the pins in that cell in their existing positions or to free them and thereby enable them to respond to the common pneumatic signals.

Computer-generated speech and man-computer interaction.

Abstract: Large-scale use of talking computers may be anticipated for reasons of general convenience and special effectiveness. A telephone link to a computer, with touch-tone inputs and stored speech outputs, poses a number of design problems of interest for the human factors specialist. Recommended features include (1) user pacing and optional repetition of speech output in a transactional sequence, (2) use of different voices and other auditory coding to distinguish types of output, and (3) use of tone codes to indicate required input.

Nonrecursive digital filtering using cascade fast Fourier transformers

Abstract: The organization of a special-purpose digital processor for performing nonrecursive digital filtering is described. The processor uses two complementary cascade fast Fourier transformers. Each transformer can simultaneously transform two independent data blocks of length N words using \log_{2} N arithmetic units and 3/2 N complex words of digital storage. Continuous filtering is achieved by sectioning the input signal, performing a fast transform on each section, multiplying by the frequency characteristics of the desired filter, and inverse transforming. The cascade organization of the processor allows processing at very high speeds. Word rates in excess of 3 MHz are possible with currently available hardware.

A multiple-precision division algorithm

Abstract: A generalized division algorithm for use with positive integral operands is presented. Depending upon the algebraic relationship of the first two ciphers of the divisor, one or at most two adjustments to the original divisor and dividend must be performed before the division operation can be initiated. The uniqueness of this method will cause each trial cipher in the quotient to be either equal to or one greater than its final replacement.

SHOEBOX: a personal file handling system for textual data

Abstract: The SHOEBOX system, a part of MITRE's long-term effort in the development of text-processing systems, is designed to be the electronic analog of a personal desk file drawer. A desk drawer is conveniently at hand and readily accessible. It contains documents, reports, adversaria---probably most of which, if the work of others, haven't been thoroughly read, or if one's own work, remain unfinished. This material is organized under whatever whimsical scheme suits one's fancy; and as one's fancy changes, the file contents are variously combined or further segregated. (Or at least one would like to perform that kind of reorganization, at present a formidable undertaking.) Needless to add, the texts are set down in a variety of formats, the only common factor among them all being a close adherence to the grammar rules of natural language. Such an unstructured environment is the bane of digital mechanization, but it is to this problem that we have addressed ourselves.

Analytic Coherent Radar Techniques for Target Mapping

Abstract: From among the many inverse shape and motion techniques considered in our work, a review is made of four methods for target mapping using coherent monostatic and multistatic measurements. These methods can provide a wide variety of shape description: surface outline, a map of discontinuities, or a viewable image in two or three dimensions. The paper discusses the form of the resulting target descriptions, as well as the kind of processing-and measurements required. In so doing, the discussion also provides an account of the nature of inverse scattering techniques in general.

Global Energy Balance

Abstract: In "Global energy balance" by D. A. Berkowitz (31 July, page 426), line 19, column 3 should read: "2.7 x 10 -2 watt/m 2 of land area."

High-Resolution, Radar Coherent Linear FM Microwave Source

Abstract: The microwave CLFM study was directed to generating 14 ?s S-band pulses of 1000 MHz bandwidth and an rms phase error of a few degrees. Over 972 MHz bandwidth, the sampled phase error relative to the reference was 7 degrees rms and 17 degrees peak, with a maximum Fourier component of 4 degrees. The FM pulse train is generated by a gated BWO driven by a stable linearizing waveform. Phase coherency during each pulse is obtained by a sampling technique, where the phase is corrected at intervals of 1/6 ?s, the RF phase having changed an integral number of cycles in each interval. Multiplication of the BWO signal by the sampling pulse train results in band-limited phase error pulses which are applied in a feedback loop. Pulse-to-pulse coherency is obtained by phase lock of the BWO starting frequency to the crystal reference. Feedback leveling holds the output constant to 0.3 dB. The basic MITRE technique was originally demonstrated at 10 MHz in 1964. Range results measured with the X-band model radar using the CLFM generator are given and confirm the phase errors of the CLFM.

Evidence for Heavy-Particle Production Processes at Energies above 2×10 11 eV

Abstract: Cosmic-ray flux measurements in the energy region ${10}^{10}$-${10}^{14}$ eV obtained by calorimeters on the satellites Proton I and II have shown results that are at variance with previous data. While a single power law provides an approximate fit to the all-particle spectrum, the primary proton flux falls sharply at energies above \ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}${10}^{11}$ eV, indicating that at high energies protons become progressively scarcer in the primary flux. The cross section for particle production by protons on carbon is found to rise by 20% in the interval between 2\ifmmode\times\else\texttimes\fi{}${10}^{10}$ and ${10}^{12}$ eV. Assuming that, in the energy region of interest, (1) the real proton flux is given by a single power law, and (2) the nuclear composition remains constant, we show that the satellite flux measurements can be explained by an energy-loss mechanism in the calorimeter, the loss being a function of the energy per nucleon rather than the total energy. Furthermore, this "$X$" process has a cross section of the right magnitude to account for the $p$-carbon cross-section measurements. The $X$ process could be described in terms of particle production or dissociation of the primary protons.

Elevation steering of the pattern of a vertical array of vertically polarized elements over a ground screen

Abstract: Patterns of vertically polarized elements above circular finite ground screens directly on soil were computed, using equations obtained recently by Wait [1]. The applicability of a steering illumination, considered optimum for an array above a perfect ground of infinite extent to the ground screen case, was investigated. It was found that this illumination gives very good results even for a modest ground screen ( 16\lambda ) in the region above 3 dB beamwidth of the aperture, consisting of the elements and the images.

An improved ATC radar beacon system

Abstract: This paper summarizes the work of the Beacon Systems Panel of the Air Traffic Control Advisory Committee.

Guidelines for Training Blind Computer Programmers.

Abstract: In drawing up guidelines for the selection, training, and placement of blind persons in computer programming, we ought to look at what to improve in our present activities. To selection, training, and placement, I would like to add a fourth phase, employment. I think it is an essential concept, one that allows us to know that the other three phases are being handled in proper perspective. What the individual blind programmer is actually doing on the job and what he gets into in the way of successes and failures are very important. I will return to this point later. To improve selection, more emphasis should be given to thorough testing and screening. This has been said before and it will be said again. Perhaps this makes some counselors unhappy, but I wish to remind them that the better the testing and screening, the greater the chance of success for those participating in the total program. There have been some trainees in the past who were marginal and whose acceptance for training was experimental. Such experimentation has been and should continue to be identified as such and be distinguished from the more regular activities of training the blind in programming. o Although we do not know what a programmer is or how to test for one very well, we do have some indications. We know that the counselor should screen clients for their employability in intellectual work. This includes mobility, emotional stability, and many other attributes that are pertinent to a man's ability to manage himself in a social and occupational environment. This must include adequate communication and study skills. Programming is intellectual work and its expression is in the form of complex, symbolic, and detailed relationships. Accuracy in these details is paramount. We know that the work is logical and requires imagination and that the programmer must be methodical and motivated. This motivation is most important in the case of the blind person because he must come to work in order to excel, not just to be there. In addition to his motivation, he must have some ability to do the work. Our problem is that we do not know how to identify these abilities with accuracy before the individual is employed and demonstrating his ability by actually doing the job. Nevertheless, the counselor should provide whatever screening and testing that is possible so that the meat grinder of vocational misplacement can be avoided. To do this, the teachers and employers must give the counselors adequate information about what is required for the job of programmer. In tum, the counselor must make sure that the

Comment on "A new procedure for calculating varactor Q from impedance versus bias measurements" [with author reply]

Abstract: The above-mentioned paper by E.W. Sard [ibid., vol. MTT-16, pp. 849-860, October 1968] claims rigor in the procedure. Although Sard mentions the possibility of variable resistance in the varactor, he does not discuss completely the effects this might have on his analysis, and the commentor (N. Houlding) contends that the reason why "(previously) losses in the external transformation circuitry must be either neglected or nonrigorously corrected for" is that the assumption of constant resistance is not justified. The commentor thinks that the problems of circuit loss and variable resistance can not be attacked independently; and, in particular, that there is no justification for assuming the varactor will not contain loss terms which will simulate the behavior of losses in a matching network. The commentor believes it is misleading to imbed the varactor in a circuit which is not the minimum-loss form and to perform an analysis assuming that the varactor resistance is constant. Houlding's detailed argument is provided. In replying, the original author (Sard) states that subject to the assumed equivalent circuit described in his Fig. 1, he still believes the method described to be completely rigorous.

Resource allocation for transportation

Abstract: A linear programming formulation is described that will permit the optimal assignment of transportation resources (vehicles) and movement requirements to a network consisting of a set of designated origins, ports of embarkation, enroute bases, ports of debarkation, and destinations to achieve a prescribed schedule of arrivals.

The structuring of health information system options: summary and assessment of methodology

Abstract: On the basis of a voluntary cooperative arrangement, The MITRE Corporation provided technical support to the Joint Center for Urban Studies (JCUS) in its Health Information System Project (see the Appendix). The major part of this effort involved, first, developing a structured approach for the characterization and analysis of System Options and, second, assisting in its application. Best described as “semi-systematic”, the approach was designed to stimulate relevant dialogue and aid decision processes in the technically-diverse, politically-sensitive, and multi-organizational Project environment. The approach contained an iterative sequence of several analytical steps, beginning with the clarification of system objectives, embodying consideration of both “operating” and “computer support” characteristics and their synthesis, and ending with the selection and planning of a preferred System Option. While its usefulness is difficult to assess fully, the approach assisted in the conception, clarification and more systematic characterization and evaluation of alternative options, and aided Project leadership in guiding debate and converging on policy decisions. Such semisystematic analytical aids are useful in attacking a variety of problems in the urban and social areas, but the degree of formal rigor and the timing must be carefully tailored to each particular situation.

Current issues in military program control

Abstract: There is currently a national furore over the way large military programs are managed. Some of it is politically or journalistically inspired. But some of it reflects a genuine disagreement over how these programs should be controlled. This paper presents a number of issues involved in the disagreement and develops the thesis that two diverging camps are being formed on their resolution: one focused on resources and the other on products. It then concludes that because there is much merit to the argument presented on both sides of many of these issues, the direction that must be taken in the program-control field is not to attempt to resolve the individual issues directly; rather it is to deal with root causes that can accommodate both points of view. It then offers a sample of three suggestions in this regard.

The State Variable Approach to System Effectiveness

Abstract: Expressions are given in the literature for the availability, mean-time-between-failures, mean uptime, and mean downtime for systems consisting of a number of identical modules in redundancy. Using the concept of superstates, vector expressions for these parameters are presented which apply to a system consisting of an arbitrary interconnection of different types of modules. A vector expression for system effectiveness is presented which is formally the same as the expression for availability in the case of a single-function system and which can be extended easily to cover multifunction systems.

Defining the Interchange of a Loop

Abstract: (1970). Defining the Interchange of a Loop. Mathematics Magazine: Vol. 43, No. 3, pp. 141-143.

Minimal realization of discrete linear systems from input/output observations

Abstract: A direct procedure is presented for obtaining a minimal realization of a linear, time invariant, discrete system from observations of input and output. It is shown that the procedure can be used for almost any input sequence. Application of the procedure requires knowledge of an upper bound on the minimal system dimension; a modification is given to handle the situation where an upper bound is not known. The structure of the realization obtained is displayed and can be used as a check on the realization. An example is included to show the operation of the procedure.

Design considerations for an infrared flying-spot telescope.

Abstract: This device combines the image-forming capability of a passive-ir line-scanning radiometer with motion sensing. The main purpose is to enhance image interpretability by adding motion information to the picture. Selection of wavelength and other salient features is discussed. The 10.6-μ wavelength has unique advantages and is the preferred choice, mainly due to the existence of high power, high efficiency cw lasers at this wavelength, coherent receiver techniques, and haze/fog penetration capability. A simplified method of estimating laser power is given, based on area scan rate as the dominant factor.