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tRAFFiC CAPABiLitiEs OF 2 REARRANGEABLY NONBLOCKiNG PHOtONiC sWitCHiNG MODULEs

At&t tECHNiCAL JOURNAL 1985年第10期64卷 2331-2373页

作者： tHOMPsON, RA AT&T Bell Laboratories. Richard A. Thompson: B. S. (Electrical Engineering) 1964 Lafayette College M. S. (Electrical Engineering) 1966 Columbia University Ph.D. (Computer Science) 1971 University of Connecticut AT&T Bell Laboratories 1963–1968 1977—.

the architectures of two small switching networks are compared as potential implementations of a 4 × 4 photonic switching module. such a module would be made by interconnecting several 2 × 2 photonic directional couplers on a single LiNbO 3 substrate. While both networks are rearrangeably nonblocking, we investigate whether one network requires significantly more rearrangements than the other. the analysis includes transient, Monte Carlo simulation, and Markov steady-state techniques. We conclude that the traffic capabilities of the two structures are not significantly different, and that selection of an architecture can be based on other criteria, like loss, crosstalk, or ease of manufacture.

关键词： tELEPHONE sYstEMs, AUtOMAtiC

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sYstEM-75 - sWitCH sERViCEs sOFtWARE

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At&t tECHNiCAL JOURNAL 1985年第1期64卷 197-212页

作者： DENsMORE, W JAKUBEK, RJ MiRACLE, MJ sUN, JH All authors are members of AT&T Information Systems Laboratories an entity of AT&T Information Systems Inc. Wayne Densmore: B.S. (Electrical and Computer Engineering) 1975 Clarkson College of Technology M.S. (Electrical and Computer Engineering) 1976 Clarkson College of Technology AT&T Bell Laboratories 1976–1983 AT&T Information Systems Laboratories 1983—. Ray J. Jakubek: B.S. (Electrical Engineering) 1967 Manhattan College M.S. 1968 and Ph.D. (Electrical Engineering) 1973 New York University Bell Laboratories 1968–1982 Michael J. Miracle: B.S. (Electrical and Computer Engineering) 1979 University of Wisconsin M.S. (Electrical Engineering) 1980 Stanford University AT&T Bell Laboratories 1979–1982 John H. Sun: B.S. (Electrical Engineering) 1972 National Chiao-Tung University Taiwan M.S. (Computer Science) 1977 University of Connecticut Taiwan Telecom Research Laboratories 1974–1975 ACCO-Bristol Company 1978 Bell-Northern Research 1979 AT&T Bell Laboratories 1980–1982

the switch services software of system 75 provides the basis for an extensible office communication system, supporting a wide variety of voice and data-switching services. this paper presents the software architecture of the system 75 switch services. the concepts of user, group, and process-per-call form its foundation. We introduce the architecture by stepping through a simple station-to-station phone call, and proceed to the derivation of a call model based on the topology of a call. this call model is realized as a layered set of cooperating processes that execute under the Oryx/Pecos Operating system on the system 75 switch processor. the software layers and processes are discussed and a call walk-through is used to illustrate the process interactions.

关键词： DiGitAL COMMUNiCAtiON sYstEMs

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A stUDY ON tHE ABiLitY tO AUtOMAtiCALLY RECOGNiZE tELEPHONE-QUALitY sPEECH FROM LARGE CUstOMER POPULAtiONs

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At&t tECHNiCAL JOURNAL 1985年第2期64卷 423-451页

作者： WiLPON, JG AT&T Bell Laboratories. Jay G. Wilpon: B.S. A.B. (cum laude in Mathematics and Economics respectively) 1977 Lafayette College Easton Pa. M.S. (Electrical Engineering/Computer Science) 1982 Stevens Institute of Technology Hoboken N.J. AT&T Bell Laboratories 1977—.

to ascertain whether a speaker-independent word recognition system, using current technology, could function in normal telephone environments, it was necessary to conduct a study under such real-world conditions. such an experiment was described by Wilpon and Rabiner (1983), in which telephone customers, speaking under ordinary telephone conditions, in Portland, Maine, were asked to speak their telephone number as a sequence of isolated digits. For each customer a maximum of four digits were obtained. the results from that study were very encouraging and led to further improvements in our recognition systems. to further study the feasibility of implementing speech recognition systems for general use over the telephone network, another field study was initiated. in this test, spoken seven-digit telephone numbers were obtained from a large number of telephone customers over a variety of transmission facilities in Baton Rouge, Louisiana. this paper presents the results of several recognition experiments performed on this database. Experiments were also carried out quantifying the robustness of template sets created in Portland, Baton Rouge, and under laboratory conditions in our Murray Hill, New Jersey, laboratory. Finally, a recognition system that incorporates syntactic information available in a seven-digit telephone is discussed. Our tests indicate a number of distinct real-world problems that must be considered when implementing a speech recognition system for widespread use. A discussion of the overall results and the implications for future research will be given.

关键词： sPEECH

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sYstEM-75 - GAMUt - A MEssAGE UtiLitY sYstEM FOR AUtOMAtiC tEstiNG

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At&t tECHNiCAL JOURNAL 1985年第1期64卷 305-320页

作者： LAKE, CJ sHANLEY, JJ siLVERstEiN, sM Authors are employees of AT&T Information Systems Laboratories an entity of AT&T Information Systems Inc. Carole J. Lake: B.A. (Mathematics) 1968 Gettysburg College M.S. (Numerical Science) The Evening College of The Johns Hopkins University 1970 National Security Agency 1968–1974 Bell Laboratories 1979–1982 AT&T Information Systems Laboratories 1983—. James J. Shanley: B.E.E. 1961 Polytechnic Institute of New York M.E.E. 1963 New York University Bell Laboratories 1955–1982 Steven M. Silverstein: B.S. (Electrical Engineering) 1973 M.S. (Electrical Engineering/Computer Science) 1974 Polytechnic Institute of Brooklyn Bell Laboratories 1973–1982

GAMUt is an automated testing tool that can verify message activity in message-based systems. this tool is unique because it can be customized for application to a variety of systems and used in all test phases of a development cycle. Using a single interface, rather than an array of port-specific interfaces, GAMUt can generate and verify load traffic through scripts, as well as provide an automatic record and playback mechanism for feature testing. this paper discusses the design philosophy and distinctive features of GAMUt as well as its architecture. it illustrates message definition and the script command language by building a sample test script of a station-to-station call on the system 75 office communications system and concludes with a discussion of challenges and problems encountered while using the tool to test system 75.

关键词： DiGitAL COMMUNiCAtiON sYstEMs

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AiR-CUsHiON LANDiNG CRAFt NAViGAtiON

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NAVAL ENGiNEERs JOURNAL 1985年第4期97卷 248-260页

作者： GRAHAM, HR KiM, JC BAND, EGU FOWLER, AW Herbert R. Graham:received his degrees of B.S. in 1951 and M.S. in 1958 in aeronautical engineering from the Massachusetts Institute of Technology and the California Institute of Technology respectively. He also attended the Harvard Graduate School of Business Administration. He is presently a task manager at TRW Inc. McLean Virginia responsible for landing craft air cushion (LCAC) engineering support. Since joining TRW in 1967 he has had several technical project management and system engineering responsibilities in amphibious ships transportation and energy. He was responsible for the preliminary engineering design and cost estimates for tracked air cushion vehicles (TACVs). He has been active in several professional societies including ASNE and served as vice-chairman Los Angeles Section American Institute of Aeronautics and Astronautics. John C. Kim:received his degrees of B.S. in electrical engineering Tri-State University 1959 M.S. in electrical engineering Michigan State University 1960 and Ph.D. in electrical engineering Michigan State University. He is presently a senior staff engineer with TRW Inc. McLean Virginia where his technical experience has included communications system engineering and navigation system analysis. Since joining TRW in 1969 he has held numerous positions including section head project manager and department manager. His previous employment includes E-Systems/Melpar Division and Honeywell. Dr. Kim has been active in the IEEE Washington Chapter activities which included secretary vice-chairman and chairman of Systems Science and Cybernetics Group. Edward G.U. Band:received a B.S. degree in mechnical engineering in 1946 and a D.I.C in aeronautical engineering in 1947 at the City and Guilds College of London University. In 1951 he received an M.S. degree from Stevens Institute of Technology in fluid dynamics. After a career in the aircraft industry in England Canada and the U.S.A. he spent several years teaching in Chile and at Webb Institute of Naval Archi

Air cushion vehicles (ACVs) have operated successfully on commercial routes for about twenty years. the routes are normally quite short; the craft are equipped with radar and radio navigation aids and maintain continuous contact with their terminals. Navigation of these craft, therefore, does not present any unusual difficulty. the introduction of air cushion vehicles into military service, however, can present a very different picture, especially when external navigation aids are not available and the craft must navigate by dead reckoning. this paper considers the problems involved when navigating a high-speed air cushion vehicle by dead reckoning in conditions of poor visibility. A method is presented to assess the ACV's navigational capability under these circumstances. A figure of merit is used to determine the sensitivity of factors which affect navigation such as the range of visibility, point-to-point distance, speed, turning radius and accuracy of onboard equipment. the method provides simplistic but adequate answers and can be used effectively to compare the-capability and cost of alternative navigation concepts.

关键词： AiR CUsHiON VEHiCLEs

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AN iMPROVED WORD-DEtECtiON ALGORitHM FOR tELEPHONE-QUALitY sPEECH iNCORPORAtiNG BOtH sYNtACtiC AND sEMANtiC CONstRAiNts

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At&t BELL LABORAtORiEs tECHNiCAL JOURNAL 1984年第3期63卷 479-498页

作者： WiLPON, JG RABiNER, LR MARtiN, t AT&T Bell Laboratories. Lawrence R. Rabiner: S.B. and S.M. 1964 Ph.D. 1967 (Electrical Engineering) The Massachusetts Institute of Technology AT&T Bell Laboratories 1962—. Jay G. Wilpon: B.S. A.B. (cum laude) in Mathematics and Economics respectively 1977 Lafayette College Easton PA M.S. 1982 (Electrical Engineering/Computer Science) Stevens Institute of Technology Hoboken NJ AT&T Bell Laboratories 1977—.

Accurate location of the endpoints of spoken words and phrases is important for reliable and robust speech recognition. the endpoint detection problem is fairly straightforward for high-level speech signals in low-level stationary noise environments (e.g., signal-to-noise ratios greater than 30-dB rms). However, this problem becomes considerably more difficult when either the speech signals are too low in level (relative to the background noise), or when the background noise becomes highly nonstationary. such conditions are often encountered in the switched telephone network when the limitation on using local dialed-up lines is removed. in such cases the background noise is often highly variable in both level and spectral content because of transmission line characteristics, transients and tones from the line and/or from signal generators, etc. Conventional speech endpoint detectors have been shown to perform very poorly (on the order of 50-percent word detection) under these conditions. in this paper we present an improved word-detection algorithm, which can incorporate both vocabulary (syntactic) and task (semantic) information, leading to word-detection accuracies close to 100 percent for isolated digit detection over a wide range of telephone transmission conditions.

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tHE ViRtUAL PROtOCOL MACHiNE

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At&t BELL LABORAtORiEs tECHNiCAL JOURNAL 1984年第8期63卷 1859-1876页

作者： FittON, MJ HARKNEss, CJ KELLEMAN, KA LONG, PF MEE, C AT&T Bell Laboratories. Michael J. Fitton: B.S. (Computer Science) 1981 Rutgers University M.S. (Computer Science) 1983 Stevens Institute of Technology AT&T Bell Laboratories 1977—. Carol J. Harkness: B.A. (Mathematics) 1969 University of Wisconsin M.S. (Computer Science) 1970 Purdue University AT&T Bell Laboratories 1969—. Keith A. Kelleman: B.S. (Electrical Engineering) 1979 Lafayette College M.S. (Computer Science) 1981 Stevens Institute of Technology AT&T Bell Laboratories 1979—. Paul F. Long: B.S. (Engineering Mathematics) 1960 M.S. (Applied Mathematics) 1963 North Carolina State University Bellcomm Inc. 1965–1972 AT&T Bell Laboratories 1972—. Carl Mee III: B.S. (Mathematics) 1957 The University of the South M.A. (Mathematics) 1964 The University of Virginia U.S. Air Force 1958–1962 Bellcomm Inc. 1964–1966 1968–1972 Informatics Inc. 1966–1968

the UNiX ™ operating system Virtual Protocol Machine (VPM) is a package of software tools that allows a wide variety of link-level data communications protocols to be implemented efficiently in a high-level language. the resulting protocol implementations are independent of the particular communications hardware, the host machine architecture, and the host operating system, and therefore can be ported easily from one hardware/software environment to another. An extension to VPM, the Common synchronous interface (Csi), provides similar benefits for the higher-level protocol software that runs in the UNiX system host. the implementations of VPM use Programmable Communications Devices (PCDs) to off load the link-level communications processing from the host CPU. A high-level language protocol description is translated by a protocol compiler that runs on the host machine. the resulting module is then loaded into the PCD and executed. the other components of VPM are a transparent protocol driver that allows user processes to interact directly with a link-level protocol implementation, a realtime trace capability to facilitate debugging, and several utility programs. VPM has been implemented on several different PCDs and several types of host computers. VPM-based protocol implementations can be ported with little or no change from one VPM implementation to another. VPM and Csi greatly reduce host system overhead while producing maximum communications throughput. A number of different higher-level protocols and their link-level counterparts have been implemented in the UNiX system using Csi and VPM; among them are X.25, 3270 emulation, a synchronous terminal interface, and a facility for remote job entry to iBM hosts.

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A NEtWORK OF computers RUNNiNG tHE UNiX sYstEM

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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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ON tHE APPLiCAtiON OF EMBEDDED tRAiNiNG tO CONNECtED LEttER RECOGNitiON FOR DiRECtORY ListiNG REtRiEVAL

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At&t BELL LABORAtORiEs tECHNiCAL JOURNAL 1984年第3期63卷 459-477页

作者： RABiNER, LR WiLPON, JG tERRACE, sG AT&T Bell Laboratories. Lawrence R. Rabiner: S.B. and S.M. 1964 Ph.D. 1967 (Electrical Engineering) The Massachusetts Institute of Technology Bell Laboratories 1962—. Sandra G. Terrace: B.S. (summa cum laude in Mathematics) 1975 Northeastern University Boston Massachusetts. Ms. Terrace works primarily from her home in Chelmsford Massachusetts where she and her husband own and operate a computer software consulting firm. She is a computer software consultant to the Acoustics Research Department of AT&T Bell Laboratories at Murray Hill New Jersey. Jay G. Wilpon: B.S. and A.B. (cum laude) in Mathematics and Economics respectively 1977 Lafayette College Easton Pennsylvania M.S. (Electrical Engineering/Computer Science) 1982 Stevens Institute of Technology Hoboken N.J. AT&T Bell Laboratories 1977—.

Automatic speech recognition has advanced to the stage where it is now possible to recognize connected strings of words (e.g., digits, letters, city names, airline terms) from a word reference set of isolated tokens of each of the words in the vocabulary. Recently, an improved training technique called embedded word training was proposed, in which reference word patterns were extracted from within connected word sequences themselves. in this investigation we extend the embedded word training procedure to handle letters of the alphabet for use in a directory listing retrieval task. By performing connected letter recognition of spoken names based on letter classes (rather than specific letters themselves), we show how reliable name recognition results can be achieved using a fairly straightforward system on 200 randomly chosen names (chosen from an 18,210-name directory) spoken at a normal rate by four talkers (three male, one female) in a speaker-trained mode. We have found that an 8-percent improvement in name recognition accuracy is obtained when using embedded letter training patterns over that obtained from isolated letter patterns alone. the overall name recognition accuracy was close to 95 percent.

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BUiLD - A sOFtWARE CONstRUCtiON tOOL

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At&t BELL LABORAtORiEs tECHNiCAL JOURNAL 1984年第6期63卷 1049-1059页

作者： ERiCKsON, VB PELLEGRiN, JF AT&T Bell Laboratories. Verlyn B. Erickson: B.A. (Mathematics/Physics) 1968 Augustana College M.S. (Computer Science) 1970 University of Wisconsin Madison Mathematics Research Center University of Wisconsin 1969–1972 Engineering Computing Laboratory University of Wisconsin 1970–1977 AT&T Bell Laboratories 1977—. John F. Pellegrin: B.A. (Mathematics) 1965 Occidental College M.A. (Mathematics) 1967 Arizona State University AC Electronics Defense Research Laboratories Goleta CA 1967–69 Ph.D. (Mathematics) 1972 Arizona State University AT&T Bell Laboratories 1972—.

the build tool is used as a sophisticated method of generating and modifying software systems. Build is being used successfully by a number of UNiX ™ software-based projects at At&t Bell Laboratories. Build is an extension to the make program that permits several software developers to independently make a collection of software while sharing the same fully populated set of directories, with the changed files residing in their own directories. An important concept in using build is software view , which represents the selection of a particular version of software for a generation environment. For example, a developer's view of a software system generally includes all of the current “official” software perturbed by the developer's private modifications to the system. A testing team's view may be the current official software perturbed by changes that a set of developers have made and have submitted for project system testing. A system user's view is a fully tested and released version of the software. the function of build is to simplify the administration of the different views of the software system. the build tool is being used by a number of large software development projects as the primary software generation tool. Build plays a central role in the development strategies and standards used in these projects.

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