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Communications, IEEE Transactions on

Issue 1  Part 1 • Date January 1982

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  • [Front cover and table of contents]

    Publication Year: 1982 , Page(s): 0
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    Freely Available from IEEE
  • Communications in the Automated Office - Guest Editor's Prologue

    Publication Year: 1982 , Page(s): 1 - 5
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    First Page of the Article
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  • Performance of CSMA/CD Networks Under Combined Voice and Data Loads

    Publication Year: 1982 , Page(s): 6 - 11
    Cited by:  Papers (30)  |  Patents (2)
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    This paper describes a simulation study of a class of carrier sense multiaccess buses with collision detection, similar to the Xerox Ethernet. The driving loads for the network models are similar to ones that might be found in an office information system which integrates data and voice communication. Various backoff algorithms are considered, to investigate the suitability of the approach and to suggest an appropriate family of architecture for communication within this medium. View full abstract»

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  • Bounding Mean Throughput Rate and Mean Delay in Office Systems

    Publication Year: 1982 , Page(s): 12 - 18
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    Offices handle a mix of jobs, with each job consisting of one or more steps. The fundamental ingredients in performance analysis are the job arrival statistics, the service required for each job step, and a scheduling policy, for a given equipment configuration. The approach is hierarchical and can be refined in numerous ways; here the authors focus on a mean value analysis: the inputs are the mean times required to execute each step of each job. A series of examples illustrate how these ingredients can be used to upper bound the mean throughput rate and lower bound the mean delay associated with each job type. View full abstract»

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  • Cost-Benefit Analysis for Local Integrated Facsimile/Data/Voice Packet Communication Networks

    Publication Year: 1982 , Page(s): 19 - 27
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    Corporate planning for the automated office requires an increasing awareness of productivity improvement offered by control of office costs. A model for analyzing the cost tradeoffs involved in adding terminals to the communication channels of a local, centralized store and forward computer network for facsimile, data, and/or voice packet switched transmission is presented. The overall cost-benefit analysis is comprised of the three models: customer requirements, network constraints and cost-benefit. The customer requirements model contains six submodels, i.e. load, processor, software, support, terminal, and telecommunications. The network constrains model is composed of the following submodels: computer node submodel, channel submodel, and terminal submodel. The cost-benefit model computes costs for links, terminals, message transactions, and their related cost-benefit ratio, given the final inputs from the network constraints model. View full abstract»

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  • A Model for Specification of Office Communications

    Publication Year: 1982 , Page(s): 27 - 36
    Cited by:  Papers (1)
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    Specification of office communications requirements necessitates the development of a communications model applicable to office processes. The model must facilitate the representation of communications processes in terms of office physical and logical organization and operation. Physical aspects include office communications equipment and their interconnections, while logical components represent such items as message profiles and information flows. A model for representation of office information communications is developed. The model is based on a paradigm consisting of a representation framework including definition of objects, attributes, and relations. Further, application of the model in the development of a language for specification of logical communication requirements and a computer-based analysis of the requirements is presented. View full abstract»

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  • A Hierarchical Architecture for Computer-Based Message Systems

    Publication Year: 1982 , Page(s): 37 - 45
    Cited by:  Papers (2)
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    In this paper the authors present an overview of an architectural model for large, distributed computer-based message systems. This model specifies (1) the organization of message systems in terms of functional entities; (2) the operation of the system; (3) the protocols and interfaces needed for interprocess communication; and (4) the organization of the directory system used to support identification services. General architectural considerations related to the communications protocols for computer-based message systems are presented; these follow the general framework of the ISO model for open system interconnection. The organization and operation of the directory system are discussed in detail. Special emphasis is given to the importance of identification services in international and interconnected message systems. View full abstract»

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  • Naming and Addressing in a Computer-Based Mail Environment

    Publication Year: 1982 , Page(s): 46 - 52
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    In a computer-based mail environment, digital addresses are sufficient to allow the mail system to perform forwarding and delivery. However, digital addresses are not easily remembered by people and some of the intelligence inherent in the system must be used to provide a more humanly engineered addressing scheme. This paper proposes a two-stage approach. In the first stage, a set of attributes is mapped into an identifier which designates a single originator or recipient (O/R) of mail. This mapping is performed via a database query dialog and is executed prior to the posting of a mail item. The O/R identifier designates an O/R invariant to its current location and is the primary information by which the mail system decides to whom mail must be delivered. In the second stage, the mail system converts the O/R identifier into an address which is then used by the mail system for forwarding and delivery. The paper discusses the relationship between a hierarchy of authority domains and the attributes and identifiers. It also analyzes the problems associated with updating the databases that support the two mapping functions. In addition, methods are developed that allow the mail system to deliver mail items correctly even under the assumption that not all databases involved contain accurate information. View full abstract»

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  • A Design Model for a Real-Time Voice Storage System

    Publication Year: 1982 , Page(s): 53 - 57
    Cited by:  Papers (1)  |  Patents (4)
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    In tomorrow's automated offices, an important role will be played by voice storage systems which enable telephone communication at any time. This paper discusses the problems and technical consideration in designing a flexible voice storage system featuring a distributed structure whose capacity can be expanded at will. Recent advances in microprocessors and magnetic minidisk devices have made this kind of system economically feasible. An efficient new method for real-time accessing of distributed files is proposed which guarantees continuous storing and forwarding of voice messages. A simple method of estimating the required file capacity is also given on the basis of a voice message traffic analysis. View full abstract»

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  • Electronic Mail for the Hearing Impaired and Its Potential for Other Disabilities

    Publication Year: 1982 , Page(s): 58 - 65
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    The introduction of electronic message systems in the office environment suggests a major new tool for the employability of physically disabled individuals. Communications barriers caused by hearing, speech, and visual impairments, as well as mobility barriers caused by paralysis and orthopedic disorders, become insignificant when individuals with such challenges have access to electronic mail. A pilot project involving deaf people clearly points to the usefulness of computer-based telecommunications not only in personal lives but also in work situations for the physically disabled. The current status of message system technology and equipment is reviewed, and recommendations are made to improve this technology to make it financially reasonable and accessible for the physically disabled consumer. View full abstract»

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  • A System for Managing Structured Messages

    Publication Year: 1982 , Page(s): 66 - 73
    Cited by:  Papers (6)  |  Patents (5)
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    Message systems send and receive messages but do not manage the information the messages contain. Database management systems manage the information of a global database but do not have a notion of address. In this paper the authors outline a prototype system which integrates the facilities of message systems and database management systems. The system manages structured messages according to their contents. The messages can be stored within a station and transferred between stations. Information present in the messages can be queried in a distributed manner. Message structure can also be exploited by automatic procedures which recognize triggering conditions and perform user specified actions. View full abstract»

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  • Database Alerting Techniques for Office Activities Management

    Publication Year: 1982 , Page(s): 74 - 81
    Cited by:  Papers (4)  |  Patents (1)
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    In this paper the authors approach the problem of office activities management from the database viewpoint. Database alerting techniques are developed to serve the purpose of office activities management. A conceptual framework for office information system design is presented. Simple database alerters and implementation techniques, existential alerters and time alerters are discussed. An example of journal editing is described in detail. Finally, alerter system stability is discussed. View full abstract»

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  • Computer Support for Group Versus Individual Decisions

    Publication Year: 1982 , Page(s): 82 - 91
    Cited by:  Papers (47)
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    This paper gives several examples of computerized conferencing systems (CCSs) which have served as group decision support systems (DSSs). In addition, the results of a controlled experiment comparing the process and outcome of group decision-making in a face-to-face versus a CCS mode are discussed. Finally, preliminary results are presented from a second controlled experiment which explored how a CCS may best be structured to serve as a group DSS for a specific type of managerial task. View full abstract»

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  • Development of a Spelling List

    Publication Year: 1982 , Page(s): 91 - 99
    Cited by:  Papers (22)  |  Patents (9)
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    The word list used by the UNIX spelling checker, SPELL, was developed from many sources over several years. As the spelling checker may be used on minicomputers, it is important to make the list as compact as possible. Stripping prefixes and suffixes reduces the list below one third of its original size, hashing discards 60 percent of the bits that remain, and data compression halves it once again. This paper tells how the spelling checker works, how the words were chosen, how the spelling checker was used to improve itself, and how the (reduced) list of 30000 English words was squeezed into 26000 16-bit machine words. View full abstract»

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  • Writing Tools

    Publication Year: 1982 , Page(s): 100 - 105
    Cited by:  Papers (2)  |  Patents (2)
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    For many people, writing is painful and editing one's own prose is difficult, tedious, and error-prone. It is often hard to see which parts of a document are difficult to read or how to transform a wordy sentence into a more concise one. It is even harder to discover that one overuses a particular linguistic construct. The system of programs described here helps writers to evaluate documents and to produce better written and more readable prose. The system consists of programs to measure surface features of text that are important to good writing style as well as programs to do some of the tedious jobs of a copy editor. Some of the surface features measured are readability, sentence and word length, sentence type, word usage, and sentence openers. The copy editing programs find spelling errors, wordy phrases, bad diction, some punctuation errors, double words and split infinitives. View full abstract»

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  • The Writer's Workbench: Computer Aids for Text Analysis

    Publication Year: 1982 , Page(s): 105 - 110
    Cited by:  Papers (7)  |  Patents (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    This paper describes the Writer's Workbench programs, which analyze English prose and suggest improvements. Some limited data on the use of the Writer's Workbench and its acceptance are also presented. The Writer's Workbench incorporates the style and diction programs, described in a previous paper of this Transactions, into a more extensive system to help writers improve their writing. The system runs under the UNIXTM operating system, and includes programs to: (1) proofread, (2) comment on stylistic features of text, and (3) provide reference information about the English language. Among other writing faults the programs detect split infinitives, errors in spelling and punctuation, overly long sentences, wordy phrases, and passive sentences. View full abstract»

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  • The Display Text Editor TED: A Case Study in the Design and Implementation of Display-Oriented Interactive Human Interfaces

    Publication Year: 1982 , Page(s): 111 - 119
    Cited by:  Patents (1)
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    The authors present the criteria used in designing the human interface of the display text editor TED and explain how the design tradeoffs were made. Although discussed in the context of a text editor, these criteria are applicable to the design of human interfaces in general. They present a critical evaluation of the TED human interface in hindsight, and suggest modifications to overcome the shortcomings thus uncovered. The new interface is judged to be less obtrusive and more flexible than its earlier version. This process of design-implementation-evaluation is essential to learning how to build good human interfaces in the future. They describe the software architecture of TED and point out how the use of sound software engineering principles has yielded a program that is easy to modify and interface to a variety of I/O devices, namely, screens, keyboards, cursor pointing devices, and voice recognition units. View full abstract»

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  • The Potential of Forms in Office Automation

    Publication Year: 1982 , Page(s): 120 - 125
    Cited by:  Papers (2)
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    Forms have been used in the design of at least three office automation systems (OfficeTalk, Odyssey, and OFS). Forms help ease the transition from a manual office system based on paper forms to a computer office system based on electronic forms. Forms also exhibit other advantages, not exploited presently, that make them very desirable for inclusion in office automation systems of the future. Potential capabilities of electronic forms are explored by focusing on three important aspects-fields, abstraction, and access rights. Electronic forms can have a large variety of fields; constraints and rules can be associated with these fields and automatically enforced. Moreover, forms are similar to abstract data types. Treating forms as abstract data types allows their being used as an abstraction tool and facilitates many kinds of automatic error checking. Finally, access rights can be associated with forms to ensure that forms are accessed and/or modified by appropriate users only. To illustrate the ideas presented, an exemplary form definition is presented and some implementation details discussed. View full abstract»

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  • Bit Error Rate Bounds for Viterbi Decoding with Modem Implementation Errors

    Publication Year: 1982 , Page(s): 129 - 134
    Cited by:  Patents (6)
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    A useful technique is derived for upper bounding the bit error rate of convolutional coding-Viterbi decoding in the presence of modem implementation errors or cochannel interference. This method utilizes the state transition matrix to find the contribution of each error event. By slightly underestimating the distance of each error path, the randomness of the implementation errors or interference can be averaged on a bit-by-bit basis. This produces an effective reduction of signal-to-noise ratio, and the elements of the state transition matrix merely reflect this reduction. The resulting bound is both accurate and very simple to apply. View full abstract»

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  • Cochannel Interference Considerations in Frequency Reuse Small-Coverage-Area Radio Systems

    Publication Year: 1982 , Page(s): 135 - 142
    Cited by:  Papers (94)
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    Frequency reuse small-coverage-area radio systems having hexagonal and square coverage areas are compared. Comparison is made on the basis of average signal to average interference (S̅/I̅) in the corners of the areas and on the basis of the expected probability of S/I exceeding some system threshold for at least one base station that is eligible to provide service. The difference in performance between square and hexagonal systems is small, smaller than the usual uncertainties in the propagation parameters needed in the performance estimates. Results suggest that, even if the signal strength decreases as slowly as the inverse cube of the distance and the standard deviation of the large scale signal variation is as large as 10 dB, good service probabilities (on the order of 99 percent) can be provided in small-coverage-area radio systems using 30-40 channel sets. View full abstract»

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  • The Power Spectral Density of Digital Modulations Transmitted Over Nonlinear Channels

    Publication Year: 1982 , Page(s): 142 - 151
    Cited by:  Papers (9)
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    This paper examines by analytical methods the power spectral densities of digital modulations (in particular, staggered and unstaggered quadrature modulations) passed through band-limited nonlinear channels. Previously observed (by computer simulation or hardware measurement) behavior of such spectra with regard to the suppression or restoration of its sidelobes after passing through the nonlinearity is verified analytically. Several examples corresponding to specific quadrature modulations and filter-nonlinearity combinations are presented as illustrations of the general results. View full abstract»

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  • Optimal Sequence Detection and Optimal Symbol-by-Symbol Detection: Similar Algorithms

    Publication Year: 1982 , Page(s): 152 - 157
    Cited by:  Papers (20)
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    An algorithm is derived which performs optimal symbol-by-symbol detection of a pulse amplitude modulated sequence. The algorithm is similar to the Viterbi algorithm with the optimality criterion optimal symbol detection rather than optimal sequence detection. A salient common feature is the merge phenomenon which allows common decisions to be made before the entire sequence is received. View full abstract»

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  • Differentially Coherent Detection of QASK for Frequency-Hopping Systems--Part I: Performance in the Presence of a Gaussian Noise Environment

    Publication Year: 1982 , Page(s): 158 - 164
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB)  

    In this paper the concept of differentially coherent detection of differentially phase-encoded QASK signals (DQASK) is described, and a receiver structure proposed. The remainder of the paper analyzes the performance of DQASK in the presence of a Gaussian noise environment with comparisons made to coherent detection of QASK. View full abstract»

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  • Differentially Coherent Detection of QASK for Frequency-Hopping Systems--Part II: Performance in the Presence of Jamming

    Publication Year: 1982 , Page(s): 165 - 172
    Cited by:  Papers (1)
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    The performance of differentially coherent detection of frequency-hopped QASK in the presence of partial-band noise and partial-band multitone jamming is presented. In each case, the worst case jamming strategy is determined which consists of specifying the worst case partial-band fraction and the corresponding maximum average error probability. The results obtained are compared with those of M-ary FH-DPSK operating in the same jamming environment. View full abstract»

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  • Performance Analysis of the SNA Virtual Route Pacing Control

    Publication Year: 1982 , Page(s): 172 - 184
    Cited by:  Papers (18)  |  Patents (1)
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    In this paper the authors provide a model and analysis of the IBM SNA virtual route pacing control used to control congestion in SNA networks. The model is appropriate to single virtual routes only. The analysis uses a Norton equivalent of the virtual route queueing model. Similar analyses of two other end-to-end window control mechanisms are carried out; one a sliding window with each message individually acknowledged, the other a fixed window control with the final message in the window only producing an acknowledgement, enabling comparisons to be made between all three. The SNA pacing control procedure, in which the first message in a given window induces an acknowledgement, is found to perform within 4 percent of the sliding window mechanism. Simulation results validate the analysis and performance curves obtained. The third window scheme, with the final message in the window generating an acknowledgement, is found to result in considerable reduction in throughput, as expected. View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Robert Schober
University of British Columbia