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A NETWORK OF computerS RUNNING THE UNIX SYSTEM

AT&T BELL LABORATORIES TECHNICAL JOURNAL 1984年第8期63卷 1877-1896页

作者： FRITZ, TE HEFNER, JE RALEIGH, TM AT&T Bell Laboratories. Thomas E. Fritz: B.S. (Chemistry) 1976 Moravian College M.S. (Computer Science) 1979 Iowa State University AT&T Bell Laboratories 1979—. Joseph E. Hefner: B.E.E. 1969 University of Dayton M.S. (Bioengineering) 1976 Polytechnic Institute of Brooklyn Sperry Rand Corporation 1969–1976 U. S. Naval Systems Center 1976–1982 AT&T Bell Laboratories 1982—. AT&T Bell Laboratories present affiliation Bell Communications Research Inc. Thomas M. Raleigh: B.S.E.E. (Electrical Engineering) 1970 The Cooper Union M.S.E.E.C.S. 1971 University of California at Berkeley AT&T Bell Laboratories 1971–1983.

This paper discusses experience in designing software to interconnect large numbers of processors that are based on the UNIX ™ operating system over a high-speed local area network. The paper discusses portability of the implementation between different processors and operating systems based on the UNIX system, the influence of different schedulers, input/output subsystems, and different speed processors on the implementation and performance of the network. Also discussed are characteristics of network usage, such as traffic patterns, throughput, and response.

关键词： computer NETWORKS

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A computer-MODEL FOR SHIPBOARD ENERGY ANALYSIS

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NAVAL ENGINEERS JOURNAL 1984年第5期96卷 33-45页

作者： DETOLLA, JP FLEMING, JR Joseph DeTolla:is a ship systems engineer in the Ship Systems Engineering Division SEA 56D5 at the Naval Sea Systems Command. His career with the Navy started in 1965 at the Philadelphia Naval Shipyard Design Division. In 1971 he transferred to the Naval Ship Engineering Center. He has held positions as a fluid systems design engineer and auxiliary systems design integration engineer. Mr. DeTolla has worked extensively in the synthesis and analysis of total energy systems notably the design development of the FFG-7 class waste heat recovery system. He is NA VSEA's machinery group computer supported design project coordinator and is managing the development of a machinery systems data base load forecasting algorithms and design analysis computer programs. Mr. DeTolla has a bachelor of science degree in mechanical engineering from Drexel University and a master of engineering administration degree from George Washington University. He is a registered professional engineer in the District of Columbia and has written several technical papers on waste heat recovery and energy conservation. Jeffrey Fleming:is a senior project engineer in the Energy R&D Office at the David Taylor Naval Ship R&D Center. In his current position as group leader for the future fleet energy conservation portion of the Navy's energy R&D program he is responsible for the identification and development of advanced components and subsystems which will lead to reductions in the fossil fuel consumption of future ships. Over the past several years he has also directed the development and application of total energy computer analysis techniques for the assessment of conventional and advanced shipboard machinery concepts. Mr. Fleming is a 1971 graduate electrical engineer of Virginia Polytechnic Institute and received his MS in electrical engineering from Johns Hopkins University in 1975. Mr. Fleming has authored various technical publications and was the recipient of the Severn Technical Society's “Best Technical Paper of the Year” award in 1

In support of the Navy's efforts to improve the energy usage of future ships and thereby to reduce fleet operating costs, a large scale computer model has been developed by the David Taylor Naval Ship Research and Development Center (DTNSRDC) to analyze the performance of shipboard energy systems for applications other than nuclear or oil-fired steam propulsion plants. This paper discusses the applications and utility of this computer program as a performance analysis tool for design of ship machinery systems. The program is a simulation model that performs a complete thermodynamic analysis of a user-specified energy system. It offers considerable flexibility in analyzing a variety of propulsion, electrical, and auxiliary plant configurations through a component building block structure. Component subroutines that model the performance of shipboard equipment such as engines, boilers, generators, and compressors are available from the program library. Component subroutines are selected and linked in the program to model the desired machinery plant functional configurations. The operation of the defined shipboard energy system may then be simulated over a user-specified scenario of temperature, time, and load profiles. The program output furnishes information on component operating characteristics and fuel demands, which allows evaluation of the total system performance.

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AN ADVANCED METHODOLOGY FOR PRELIMINARY HULL FORM DEVELOPMENT

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NAVAL ENGINEERS JOURNAL 1984年第4期96卷 147-161页

作者： LIN, WC DAY, WG HOUGH, JJ KEANE, RG WALDEN, DA KOH, IY Wen-Chin Lin:heads the Ship Powering Division at the David Taylor Naval Ship R&D Center (DTNSRDC). Dr. Lin received his B.S. degree in mechanical engineering from the National Taiwan University in 1957. He was awarded his M.S. degree in naval architecture and Ph.D. in engineering science from the University of California at Berkeley in 1963 and 1966 respectively. From 1966 to 1969 he was employed by ESSO Research and Engineering Company to conduct marine hydrodynamic research for oil tankers and offshore structures. Since joining DTNSRDC in 1969 he has actively conducted and directed hydrodynamic research to advance naval ship design technology and improve ship performance. Active in national and international symposia on ship hydrodynamic research he is recognized for contributions to the ship research community. For the past six years he has been a member of the Performance Committee of the ITTC and currently serves as secretary of the committee. He is a member of SNAME and the Society of Naval Architects of Japan. William G. Day Jr:. has been employed as a naval architect at the David Taylor Naval Ship R&D Center since receiving a B.E.S. degree from the Johns Hopkins University in 1966. He obtained an M.S. E. degree from George Washington University in 1971. As Head Design Evaluation Branch of the Ship Performance Department he is responsible for model experiments to evaluate the hydrodynamic performance of ships and propulsors. He is a member of ASNE and SNAME. In-Young Koh:received his B.S. and M.S. degrees in electrical engineering from Lowell University in 1969 and 1971 respectively and his Ph.D. in applied mechanics from Rensselaer Polytechnic Institute in 1976. Dr. Koh joined DTNSRDC as an electronic engineer specializing in the application of advanced instrumentation and computer techniques to ship research and design. He is currently engaged in research and development of active control systems for naval ship applications. Dr. Koh is a member of ASNE SNAME and IEEE. David Andrew Walden:is

A ship design methodology is presented for developing hull forms that attain improved performance in both seakeeping and resistance. Contrary to traditional practice, the methodology starts with developing a seakeeping-optimized hull form without making concessions to other performance considerations, such as resistance. The seakeeping-optimized hull is then modified to improve other performance characteristics without degrading the seakeeping. Presented is a point-design example produced by this methodology. Merits of the methodology and the point design are assessed on the basis of theoretical calculations and model experiments. This methodology is an integral part of the Hull Form Design System (HFDS) being developed for computer-supported naval ship design. The modularized character of HFDS and its application to hull form development are discussed.

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RIGHT-ANGLE REFLECTION OF SAW FROM AN ARRAY OF CONDUCTING STRIPS

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IEEE TRANSACTIONS ON SONICS AND ULTRASONICS 1983年第2期30卷 90-99页

作者： BERTONI, HL Department of Electrical Engineering and Computer Science Polytechnic Institute of New york University Brooklyn NY USA

The propagation characteristics of surface acoustic waves (SAW) are studied for the case of propagation under an array of conducting strips, when the direction of propagation is 45° to the strips. For frequencies in the stopband, this configuration leads to right-angle reflection of the SAW for materials that have a reflection symmetry plane lying perpendicular to the strips. An example of such a configuration is (110) propagation on Z-cut BGO. The location of the stopband and the reflection coefficient R per strip are determined as a function of the array geometry and the piezoelectric coupling constant ΔV/VR of the material. The conducting strips are assumed to be of vanishing thickness so that they influence the SAW only through its electric fields. Copyright © 1983 by The institute of Electrical and Electronics Engineers, Inc.

关键词： Surface acoustic waves Frequency Acoustic reflection Acoustic arrays Acoustic propagation Conducting materials Piezoelectric materials Surface acoustic wave devices Strips Attenuation

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ANALYSIS AND DESIGN OF FREQUENCY SCANNED TRANSMISSION GRATINGS

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RADIO science 1983年第4期18卷 513-518页

作者： SHMOYS, J HESSEL, A Department of Electrical Engineering and Computer Science Microwave Research Institute Polytechnic Institute of New York Farmingdale New York 11735

A transmission grating can be used as a frequency scanned antenna, provided most of the incident power is transferred to the diffracted mode, i.e., the grating is blazed. A design procedure for blazing a rectangular bar transmission grating is presented. The performance of a number of gratings is presented. Efficiencies in excess of 99% can be obtained at a single frequency. A scan range of 55° between 3-dB points can be obtained.

关键词： Gratings Diffraction Bragg gratings Diffraction gratings Reflection Antennas Bars

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HYBRID GREENS-FUNCTION FOR SH MOTION IN A LOW VELOCITY LAYER

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WAVE MOTION 1983年第1期5卷 83-97页

作者： KAMEL, AH FELSEN, LB Department of Electrical Engineering and Computer Science Microwave Research Institute Polytechnic Institute of New York Farmingdale NY 11735 USA

Wave motion in an elastic layer has been analyzed conventionally either in terms of normal (discrete and continuous) mode spectra or in terms of ordinary or generalized ray fields. Either of these representations is inconvenient for describing the motion over the entire range of observations from early to late arrivals. A recently developed hybrid formulation, wherein modal fields, ray fields and a remainder are combined according to specified criteria within a single rigorous framework, overcomes these difficulties, Combinations may be chosen that ensure smooth passage from the ray phase at early times to the modal phase at later times. The method is illustrated here on the two-dimensional time-dependent SH Green's function for a homogeneous sediment layer above a higher velocity homogeneous semi-infinite bedrock, with the source located in the sediment. The hybrid fields may include various combinations of trapped modes, leaky modes, trapped rays, leaky rays, and lateral rays (head waves). This study complements an earlier investigation wherein the source was located in the bedrock.

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CREEPING WAVES AND RESONANCES IN TRANSIENT SCATTERING BY SMOOTH CONVEX OBJECTS

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1983年第3期31卷 426-437页

作者： HEYMAN, E FELSEN, LB Department of Electrical Engineering Computer Science Microwave Research Institute Polytechnic Institute of New york University Farmingdale NY USA

Scattering by smooth convex objects, excited by a transient field with broad spectral content, has been analyzed either by ray formulations, which are useful at observation times descriptive of the early arrivals, or by the complex resonances of the singularity expansion method (SEM), which are most appropriate at intermediate and late observation times. Within the framework of SEM, efforts have recently been made to show that in a grouping of the resonances along "layers," rather than along the conventional "arcs" based on an angular harmonic field representation, the higher order resonances behave collectively like a wave traveling circumferentially around the object. This observation has provided the stimulus for the present investigation in which the relation between the wavefront arrivals (creeping waves) and the SEM resonances is placed on a rigorous basis. Using a perfectly conducting circular cylinder as a canonical model, this is done by direct application of the theory of characteristic Green's functions to construct alternative field solutions, and by collective summation of groups of wavefront arrivals or groups of resonances. The connection between creeping waves and resonances thus having been established, hybrid formulations are developed which combine the creeping waves and the SEM resonances within a single rigorous framework so as to maximize the utility of each over the entire range of observation times. These results are then generalized to smooth cylindrical objects with noncircular convex shape.

关键词： Resonance Scattering Frequency Transient analysis Shape Time factors Engine cylinders

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AN ADAPTIVE ROBUSTIZING APPROACH TO KALMAN FILTERING

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AUTOMATICA 1983年第3期19卷 279-288页

作者： TSAI, C KURZ, L Department of Electrical Engineering and Computer Science Polytechnic Institute of New York Brooklyn NY 11201 United States

The performance of a linear Kalman filter will degrade when the dynamic noise is not Gaussian. A robust Kalman filter based on the m -interval polynomial approximation (MIPA) method for unknown non-Gaussian noise is proposed. Two situations are considered: (a) the state is Gaussian and the observation noise is non-Gaussian; (b) the state is non-Gaussian and the observation noise is Gaussian. It is shown, as compared with other non-Gaussian filters, the MIPA Kalman filter is computationally feasible, unbiased, more efficient and robust. For the scalar model, Monte Carlo simulations are given to demonstrate the ideas involved.

关键词： adaptive systems Kalman filters non-Gaussian noise nonlinear filters robust filtering

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ON LIFE BEHAVIOR UNDER SPECTRUM LOADING

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engineering FRACTURE MECHANICS 1983年第2期18卷 271-283页

作者： KOZIN, F BOGDANOFF, JL Department of Electrical Engineering and Computer Science Polytechnic Institute of New York Route 110 Farmingdale NY 11735 U.S.A.

B- models are used to study life in cumulative damage under spectrum loading. The basic elements of scatter in sample cdf's, mean cdf, methods of testing and load interaction are delineated and examined in some detail. Application to one set of life data under spectrum loading is considered. Stationary and nonstationary B- models of life under spectrum loading are discussed.

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SPECTRAL THEORY OF SOUND-PROPAGATION IN AN OCEAN CHANNEL WITH WEAKLY SLOPING BOTTOM

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JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1983年第4期73卷 1120-1130页

作者： KAMEL, A FELSEN, LB Department of Electrical Engineering and Computer Science Microwave Research Institute Polytechnic Institute of New York Farmingdale New York 11735

Spectral representations based on the theory of characteristicGreen’s functions (resolvents) have been used effectively for studying sound propagation in a coordinate separable ocean environment. Such representations are here generalized to accommodate weak nonseparability as represented by a homogeneous water channel separated from a homogeneous sediment by a gradually and monotonically sloping bottom. The generalization involves the use of adiabatic invariants for the spectral integration variable and of symmetrizing factors in order to insure that the Green’s function, so expressed, reduces by residue calculus to the conventional adiabatic trapped mode expansion whenever that is valid. However, subject to ignoring coupling between the adiabatic modes, the generalized Green’s function contains all of the spectral information (discrete and continuous) for upslope propagation from a source to arbitrary observation points in the water or the bottom, and it can be used to derive ray, hybrid ray‐mode, and other formulations in this configuration. Numerical evaluation of the spectral integral and comparison with results obtained independently by the parabolic equation algorithm have confirmed its validity for a typical range of observer locations. Asymptotic considerations have been employed to clarify the mechanism of adiabatic mode transition from trapped to radiating in terms of lateral and leaky waves, and to reduce the spectral integral to a simpler canonical transition function similar to those of Pierce [J. Acoust. Soc. Am. 7 2, 523–531 (1982)] and of Arnold and Felsen [J. Acoust. Soc. Am. 7 3, xxx–xxx (1983)] which were derived by entirely different methods.

关键词： Green&apos s function methods Oceans Sound propagation Underwater sound Acoustical properties

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