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Showing papers by "Mitre Corporation published in 1978"


Patent
18 Jul 1978
TL;DR: In this paper, a method and apparatus employing spread spectrum techniques in a wide bandwidth communications system is disclosed, where a plurality of transmitting stations are each equipped to provide a transmission signal representing a pseudo-random coded, phase modulated, message signal.
Abstract: A method and apparatus employing spread spectrum techniques in a wide bandwidth communications system is disclosed. A plurality of transmitting stations are each equipped to provide a transmission signal representing a pseudo-random coded, phase modulated, message signal. The transmission signal is directed through a bandwidth which encompasses otherwise dedicated, relatively narrow bandwidth repeater channels, employed in connection with a communications satellite, to a generally fixed receiver station. At the receiving station, the incoming signal is (a) code acquired and tracked, (b) carrier acquired and tracked, (c) phase locked to the receiver local oscillator and (d) coherently demodulated to extract the desired data. The receiving station advantageously employs plural receiving elements each having a pseudo-random sequence code matched filter which significantly reduces code acquisition time by obviating the necessity of exhaustively correlating the incoming signal with a replica of the pseudo-random code word at the receiver station.

117 citations


Journal ArticleDOI
TL;DR: The outlook for the mutual satisfaction of both sets of users is something less than promising as discussed by the authors, if Congress continues to mandate Federal agency evaluation with the intention of establishing agency accountability while agencies are instead sponsoring evaluation in order to improve program management.
Abstract: It seems that evaluation means many things to many people. If Congress continues to mandate Federal agency evaluation with the intention of establishing agency accountability while agencies are instead sponsoring evaluation in order to improve program management, the outlook for the mutual satisfaction of both sets of users is something less than promising.

23 citations


Journal ArticleDOI
T. D. C. Kuch1
TL;DR: The number of authors of papers in four scientific journals is positively correlated with the number of significant words in the titles of the same papers, and a fifth journal showed no correlation.
Abstract: The number of authors of papers in four scientific journals is positively correlated with the number of significant words in the titles of the same papers. A fifth journal showed no correlation. Implications for information retrieval are explored and tentative explanations are offered.

14 citations


Journal ArticleDOI
TL;DR: This paper describes the procedures used for estimating the impact of alternative telemedicine technologies on the delivery of primary care in rural areas and the use of telecommunication technologies for conducting consultation between remotely located non-physicians and physicians.
Abstract: A scarcity of health care workers attributable to the present maldistribution of physicians is one of the most pressing health care delivery problems in rural America. Expanded utilization of non-physician primary health care providers is a possible solution to this problem. The capability of satellite clinics staffed by these personnel to provide ambulatory services efficiently and effectively can be enhanced by reducing the need for physical referral of the patients to a physician at a central clinic. The use of telecommunication technologies for conducting consultation between remotely located non-physicians and physicians can potentially reduce the required number of such referrals. This paper describes the procedures used for estimating the impact of alternative telemedicine technologies on the delivery of primary care in rural areas. Non-physician protocols were used to measure the impact of technology.

10 citations


01 Jan 1978
TL;DR: In this paper, a Monte Carlo simulation model of radiative transfer in turbid water is discussed, which can be used to calculate characteristics of the backscattered signal from an illuminated body of water as a function of the turbidity level and spectral properties of the suspended particulates.
Abstract: A Monte Carlo simulation model of radiative transfer in turbid water is discussed. The model can be used to calculate characteristics of the backscattered signal from an illuminated body of water as a function of the turbidity level and spectral properties of the suspended particulates. The dependence of remote sensing applications on the concentration and spectral properties of sediments in the environmental waters is considered in terms of the model. Attention is directed to the effects of various inputs for the volume-scattering function on backscattered radiance from natural waters. The wavelength dependence of single scattering albedo is investigated.

7 citations


Proceedings ArticleDOI
J.K. Millen1
13 Nov 1978
TL;DR: The confinement problem is how to constrain untrusted software in such a way that information made available to it is not passed along to unauthorized indi viduals.
Abstract: The confinement problem is how to constrain untrusted software in such a way that information made available to it is not passed along to unauthorized indi viduals. One type of attack on this problem is to have the supervisor or operating system control all memory accesses according to a suitable policy. The security kernel is that part of an operating system or supervisor whose correctness is supposed to be sufficient for the desired protection.

6 citations


Journal ArticleDOI
TL;DR: It is found that Lansdell numerals are read at least 15% more slowly than Mackworth or Elite numbers when groups of five symbols are scanned for a target digit, and are read 34% more Slowly when the five digits in each group must be added.
Abstract: In contrast with earlier research showing Lansdell numerals superior in legibility to conventional number shapes during brief exposure of single digits, the present study found that Lansdell numerals are read at least 15% more slowly than Mackworth or Elite numbers when groups of five symbols are scanned for a target digit, and are read 34% more slowly when the five digits in each group must be added. This lower readability indicates that Lansdell numerals should not be used in situations requiring interpretation of displayed numbers, i.e., should not be used for most display applications.

4 citations


Journal ArticleDOI
TL;DR: In this article, a nonlinear dynamic model of a commercial scale high temperature gas-cooled reactor (HTGR) steam power plant was derived in state-space form from fundamental principles.
Abstract: A nonlinear dynamic model of a commercial scale high temperature gas-cooled reactor (HTGR) steam power plant was derived in state-space form from fundamental principles. The plant model is 40th order, time-invariant, deterministic and continuous-time. Numerical results were obtained by digital simulation. Steady-state performance of the nonlinear model was verified with plant heat balance data at 100, 75 and 50 percent load levels. Local stability, controllability and observability were examined in this range using standard linear algorithms. Transfer function matrices for the linearized models were also obtained. Transient response characteristics of 6 system variables for independent step disturbances in 2 different input variables are presented as typical results. Simulation of the HTGR steam power plant provides the basis for (a) understanding the complex and highly interactive process dynamics, (b) designing an interactive multivariable controller, and (c) studying plant dynamic performance under various operating and upset conditions. Modeling and simulation techniques developed in the work from which this paper is abstracted have general applicability, and can be readily adapted to the study of gas-cooled steam power plants.

3 citations


Journal ArticleDOI
TL;DR: In this article, a nonlinear dynamic model of a multicell, atmospheric-pressure, fluidized-bed combustion steam generator is developed in state-space form, and the model can be readily adapted to other CFGs.
Abstract: A nonlinear dynamic model of a multicell, atmospheric-pressure, fluidized-bed combustion steam generator is developed in state-space form. All model parameters are physical quantities derived from design data, and the model can be readily adapted to other fluidized-bed combustion steam generators. Steady-state performance of the nonlinear model is predicted at 100, 87.5, and 75% load levels, and local stability is examined in this range. Frequency response characteristics of several system variables and transient response of the system following a coal feed rate disturbance are presented to illustrate use of the model.

3 citations


Proceedings Article
01 Jan 1978
TL;DR: In this article, an integral glass test module has been fabricated and subjected to environmental testing using electrostatic bonding and the results showed that the test module's performance was excellent and it could be used for solar arrays.
Abstract: An excellent encapsulation system for a terrestrial solar array can be formed using two sheets of glass. Superior technical character, very low cost and simple assembly can result if the active components and the glass sheets are integrally bonded together such that the array is hermetically sealed without employing organic encapsulation materials. Such an approach is being developed using electrostatic bonding. Status of this development is described. Functioning integral glass test modules have been fabricated and subjected to environmental testing. Results have been excellent.

3 citations


Proceedings ArticleDOI
22 Mar 1978
TL;DR: The concept, design, and evaluation of two similar Loran C land vehicle tracking systems developed by MITRE are presented and one was configured to automatically display the reported status and location of two emergency medical service vehicles to aid in more efficient dispatch and control functions.
Abstract: The concept, design, and evaluation of two similar Loran C land vehicle tracking systems developed by MITRE are presented. One system was developed to provide field demonstrations of applications of Loran C location techniques such as highway inventory accounting, highway accident site recording, control and dispatch of emergency and law enforcement vehicles, and control of mass transit vehicles. The second system was configured to automatically display the reported status and location of two emergency medical service (EMS) vehicles to aid in more efficient dispatch and control functions. The Loran coordinates of the vehicle are transmitted to the base station where a microcomputer resolves the Loran coordinates into geographic/display coordinates and displays the vehicle location. Accurate Loran C land vehicle tracking requires calibration of the Loran signals to respective geographic or map coordinate locations. The two systems being discussed use a linear approximation of the hyperbolic Loran grid. The Loran coordinate to display screen position algorithm is, therefore, linear. Automatic tracking Loran receivers are installed in the vehicles. The receivers have been modified to output an audio band signal containing the two Loran time coordinates, the internal status of the receiver, a vehicle identification code, and 1 of 8 vehicle status codes entered on a manual keyboard located in the vehicle. A transmitter key control is also available. Commercial land mobile radios are used for transmission and reception of the audio signal. The land mobile receiver output at the base station is demodulated by a commercially available demodulator and input to the microcomputer on a serial port. After initialization of the system, map display, tracking, screen refresh, and status reporting are all automatic.

Book ChapterDOI
01 Jan 1978
TL;DR: An analytical tool developed and applied to plan for, the use of telecommunications technology to link a non-physician health care provider in a rural satellite clinic to a central source of medical expertise found that telephone-compatible, narrowband technologies could avert nearly two-thirds of the travel that could be averted with broadband technologies.
Abstract: This paper presents an analytical tool developed and applied to plan for, the use of telecommunications technology to link a non-physician health care provider in a rural satellite clinic to a central source of medical expertise. An implicit underlying hypothesis was that high technology plus lower skills (non-physicians) would be “equivalent” in some to-be-defined sense to low technology plus higher skills (physicians). The measurement tool developed to compare the performance of such different manpower/technology combinations is based on the concept of a “patient trajectory,” the sequenced set of interactions that take place between a patient and the health care system from the time the patient perceives a need for medical care for some problem until that problem is resolved. For a fixed non-physician man- power level (defined by medical protocols, three Independent physicians estimated the ability of different telecommunications technologists to avert patient travel at decision points within the protocols that called for physician consultation or referral. These judgments) were used as inputs to a computer simulation to assess prospectively the overall effects on reducing patient travel that might be expected from each of several telecommunications technologies, The major result obtained was that telephone-compatible, narrowband technologies (such as slow-scan television) could avert nearly two-thirds of the travel that could be averted with broadband technologies


Proceedings ArticleDOI
J.S. Ludwick1
22 Mar 1978
TL;DR: In this article, a test of the location sub-system of four Automatic Vehicle Monitoring (AVM) systems in Philadelphia has been examined to determine characteristics useful in the employment of each technique in an operational system.
Abstract: Data collected during a test of the location sub-system of four Automatic Vehicle Monitoring (AVM) systems in Philadelphia have been examined to determine characteristics useful in the employment of each technique in an operational system. A properly chosen algorithm can give accurate time point results of buses stopping at bus stops, but the addition of a door switch can provide greater reliability. Components of location error of each system can be fit graphically on normal probability paper, using linear segments with two different slopes. Some of the error components can be fit very well by a probability distribution composed of a sum of two normal distributions. The resultant distribution has more small errors and more large errors than would result from a single normal distribution. Although most systems exhibit a statistically significant bias, which could be removed during the location determination process, the amount is small compared to system requirements. Incorporation of signpost data improved LORAN-only accuracy approximately threefold.

01 Mar 1978
TL;DR: In this paper, a Monte Carlo simulation method was used to determine the effect of scattering from turbid water on the polarization of a backscattered beam of laser light, and the relationship between the polarization and the type and amount of suspended particulates in the water was investigated.
Abstract: A Monte Carlo simulation method was used to determine the effect of scattering from turbid water on the polarization of a backscattered beam of laser light. The relationship between the polarization and the type and amount of suspended particulates in the water was investigated.

Proceedings ArticleDOI
10 Nov 1978
TL;DR: In this article, an approximate closed-form solution of the radiative transport equation in turbid media is presented and compared with other standard closed form solutions such as quasi-single scattering approximations.
Abstract: Quantitative analytical procedures for relating selected water quality parameters to the characteristics of the backscattered signals, measured by remote sensors, require the solution of the radiative transport equation in turbid media. In this paper, we present an approximate closed form solution of this equation and based on this solution discuss the remote sensing of the sediments. The results are compared with other standard closed form solutions such as quasi-single scattering approximations.

Journal ArticleDOI
01 Aug 1978
TL;DR: The MITRE program as discussed by the authors is an example of a successful industry-developed continuing educational activity in which many companies are engaged and as such may be useful to those who are designing such programs of their own.
Abstract: The problem of providing stimulating, effective continuing education for experienced professionals is becoming more acute for industry as technology's development accelerates. Faced with this problem, The MITRE Corporation has developed an in-house educational program whose learning environment is designed to meet the needs of its technical staff: personnel of widely differing educational backgrounds and professional experience. The course format emphasizes problem solving, personal communications, and teamwork. The latest adult education techniques are used and classroom facilities and decor are designed to encourage interaction and interchange of ideas and experiences. The program has proved successful. Learning by doing and personal involvement in team activity have provided motivation and kept interest high, and the cross-fertilization achieved by the interaction among the students has been a valuable byproduct. This paper presents the MITRE program as an example of a successful industry-developed continuing educational activity. It is representative of the kinds of continuing educational activities in which many companies are engaged and as such may be useful to those who are designing such programs of their own.

Journal ArticleDOI
TL;DR: One of the main conclusions drawn from the economic analysis is that a reasonable transition plan to either LORAN–C or NAVSTAR–GPS, if they are successful, would be to accommodate the more high performance users with these systems, and retain only the Vor part of the VOR/DME system for service to lower performance users.
Abstract: there has been recent concern within the government about the “proliferation of radio navigation systems.” Today, the prime domestic civil air navigation system (VOR/DME) is essentially only usable by aviation due to line–of–sight restrictions. With the availability of wider coverage systems, and low cost microprocessor based user equipment, it may be possible to consolidate air, marine, and land navigation services into one system to be operated by the government. However, each of these services has its own peculiar requirements. The purpose of this paper is to evaluate the feasibility of introducing other navigation systems into the VOR/DME system environment. In particular, two of the most promising systems, LORAN–C and NAVSTAR–GPS, are considered. The issues that are addressed concern the distribution of costs between the users and government, distribution of costs among the various classes of users, user amortization of VOR/DME equipment, signal–in–space redundancy requirements, relationships to landing and communications airborne equipment, and satisfaction of operational requirements. Future implementation scenarios are outlined and subjected to economic analysis. One of the main conclusions drawn from the economic analysis is that a reasonable transition plan to either LORAN–C or NAVSTAR–GPS, if they are successful, would be to accommodate the more high performance users with these systems, and retain only the VOR part of the VOR/DME system for service to lower performance users.

Journal ArticleDOI
Ersch Rotholz1
TL;DR: The paper investigates in detail the trade-off between bandwidth and intermodulation interference of multicarrier signals if the signal carriers are arranged in appropriate frequency plans.
Abstract: Intermodulation interferences of multicarrier signals can be reduced at the expense of increased bandwidth if the signal carriers are arranged in appropriate frequency plans. The paper investigates in detail the trade-off between bandwidth and intermodulation interference. The results are presented in tabular form.

Book ChapterDOI
01 Jan 1978
TL;DR: In this article, the authors discuss background relevant to Fluidized-Bed Combustion (FBC) technology and describe the sampling and analytical strategy recommended for its environmental assessment.
Abstract: Publisher Summary This chapter discusses background relevant to Fluidized-Bed Combustion (FBC) technology and describes the sampling and analytical strategy recommended for its environmental assessment. FBC is an available technology which, when implemented on a commercial scale, can greatly increase the utility of coal as an environmentally acceptable source of energy. The technology involves the combustion of coal in a bed of inert ash and limestone or dolomite that has been fluidized by the uniform injection of air through the bottom of the bed at controlled rates. Assessment of the physical conditions present in streams selected for sampling is prerequisite to the specification of appropriate sampling procedures. Two important parameters influencing technique selection are stream static pressure and temperature. Sampling of all streams takes place at approximately atmospheric pressure for both the atmospheric and pressurized FBC systems.

Proceedings ArticleDOI
W. Scales1
01 Jul 1978

01 Apr 1978
TL;DR: In this paper, a program was conducted for design, fabrication and evaluation of twelve silicon solar cell modules and the purpose of the program was to develop a module design consistent with the requirements and objectives of JPL specification and to also incorporate elements of new technologies under development to meet LSSA Project goals.
Abstract: A program conducted for design, fabrication and evaluation of twelve silicon solar cell modules is described. The purpose of the program was to develop a module design consistent with the requirements and objectives of JPL specification and to also incorporate elements of new technologies under development to meet LSSA Project goals. Module development emphasized preparation of a technically and economically competitive design based upon utilization of ion implanted solar cells and a glass encapsulation system. The modules fabricated, tested and delivered were of nominal 2 X 2 foot dimensions and 20 watt minimum rating. Basic design, design rationale, performance and results of environmental testing are described.

Journal ArticleDOI
TL;DR: How the training was performed using a voice-operated terminal, the successes and problems encountered, and how the course led to Rick's status as an entry-level computer programmer are related.
Abstract: This paper describes an experimental vocational course for Richard (Rick) Pilgrim, a homebound quadriplegic. The goal of this program was to develop training techniques which might prepare Rick for a profession as a computer programmer. This paper relates how the training was performed using a voice-operated terminal, the successes and problems encountered, and how the course led to Rick's status as an entry-level computer programmer.

Journal ArticleDOI
Asok Ray1
TL;DR: In this article, a practical application of a novel parameter identification technique for industrial process control systems is presented, based on numerical inversion of the Laplace Transform, as proposed by Bellman, et al.
Abstract: A practical application of a novel parameter identification technique for industrial process control systems is presented. The solution algorithm is based on numerical inversion of the Laplace Transform, as proposed by Bellman, et al. Its application with the aid of a minicomputer (or a desk calculator) is fairly easy and fast. Using this method, process gain and time-constants of an electric furnace with on- off control are evaluated. Results of an experimental study are presented to validate the theoretical predictions. This identification technique is suitable for a wide range of industrial processes, and it can be applied to direct digital control systems.

Journal ArticleDOI
01 Aug 1978-Energy
TL;DR: In this paper, the authors present a simple and systematic approach to derive energy resource utilization projections using geothermal resources as an example, based on experience with conceptually similar industries and demands on exogenous physical resources and institutional constraints.

Journal ArticleDOI
S. C. Mohleji1
TL;DR: In this article, an approach for the ATC system in the terminal area to accommodate fuel conserving landing approaches is described, and analytical results are presented that illustrate the impact of fuel economic design on terminal controllability and airport capacity.
Abstract: In a high density terminal area, speed control and radar vectoring are typically used to optimize the sequence and assure the spacing of landing aircraft for maximum runway utilization. Fuel conservative descent and landing approaches tend to offer reduced control capability to the extent that they depend upon relatively inflexible paths and rigid speed profiles. Under high traffic demands the loss in terminal controllability could adversely impact both airport capacity and fuel consumption through increased delays. This paper describes an approach for the ATC system in the terminal area to accommodate fuel conserving landing approaches. Analytical results are presented that illustrate the impact of fuel economic design on terminal controllability and airport capacity. Peak hour trade–offs between conserving fuel and maximizing runway utilization are also included in the paper. An analytical fuel consumption model is used to estimate the fuel benefits of lifting the 250 knots speed restriction below 10,000 ft. MSL, for both arrivals and departures.

Book ChapterDOI
01 Jan 1978
TL;DR: In this paper, the authors present some recommended procedures for multimedia sampling and analysis of fluidized-bed combustion systems, which are consistent with the phased environmental assessment strategy, and provide detailed instructions for use by sampling and analytical personnel.
Abstract: Publisher Summary This chapter presents some recommended procedures for multimedia sampling and analysis of fluidized-bed combustion systems. These procedures apply to the generic processes and are consistent with the phased environmental assessment strategy. The chapter summarizes and highlights techniques and provides key references wherein detailed instructions, for use by sampling and analytical personnel, can be found. The chapter focuses on the analytical rather than the sampling aspects of the assessment program. The chapter presents recommended procedures for phased, multimedia chemical characterization of the FBC process streams previously selected for sampling. Procedures for a given analysis area are, for the most part, independent of sample type and, in addition, are insensitive to process configuration. Sample preparation procedures, however, may vary with the type of sample.


E. L. Keitz1
01 May 1978
TL;DR: In this article, the authors present information and numerical evaluations used in the development of mission evaluations for stratospheric trace constituent measurement; and various spatial and temporal distributions for those stratosphere trace species having sufficient measurements available to warrant their presentation.
Abstract: Contained in this volume is material of a supportive nature not considered to be of sufficient importance to be included in the other two previous volumes. This material is of two types:(1) information and numerical evaluations used in the development of mission evaluations for stratospheric trace constituent measurement;and (2) various spatial and temporal distributions for those stratospheric trace species having sufficient measurements available to warrant their presentation.

E. L. Keitz1
01 May 1978
TL;DR: Stratospheric trace constituent measurement requirements are separated into two somewhat overlapping areas in this paper, where the only problem of interest is ozone; its chemistry chain, environmental effects and measurement requirements.
Abstract: Stratospheric trace constituent measurement requirements are separated into two somewhat overlapping areas In the first area, it is assumed that the only problem of interest is ozone; its chemistry chain, environmental effects and measurement requirements In like manner, in the second area it is assumed that the only problem of interest is stratospheric aerosols; their chemistry, effects and measurement requirements