Showing papers on "Systems architecture published in 1981"

Beyond Question-Answering.

Abstract: : We demonstrate, using protocols of actual interactions with a question-answering system, that users of these systems expect to engage in a conversation whose coherence is manifested in the interpendence of their (often unstated) plans and goals with those of the system. Since these problems are even more obvious in other forms of natural-language understanding systems, such as task-oriented dialogue systems, techniques for engaging in question-answering conversation should be special cases of general conversational abilities. We characterize dimensions along which language understanding systems might differ and, based partly on this analysis, propose a new system architecture, centered around recognizing the user's plans and planning helpful responses, which can be applied to a number of possible application areas. To illustrate progress to date, we discuss two implemented systems, one operating in a simple question-answering framework, and the other in a decision support framework for which both graphic and linguistic means of communication are available. (Author)

Practical Natural-Language Processing by Computer

Abstract: : This paper describes the state of the art in practical computer systems for natural-language processing. We first consider why one would want to use natural language to communicate with computers at all, looking at both general issues and specific applications. Next we examine what it really means for a system to have a natural-language capability. This is followed by a discussion of some major limitations of current technology. The bulk of the paper is devoted to looking in detail at a single application of natural-language processing: database retrieval by natural-language query. We lay out an overall system architecture, explaining what types of processing and information are required. Then we look at two general classes of systems, special-purpose and general-purpose, explaining how they differ and their relative advantages and disadvantages. Afterwards we point out some remaining problems that will require additional basic research. Finally we conclude by discussing when language-processing technology at various levels of capability is likely to be commercially practical, and what it may cost to develop and use applications of that technology.

Combined mode supervisory program-panel controller method and apparatus for a process control system

Abstract: A combined mode program-panel controller method for a distributed industrial process control system permits a system operator to configure the overall system architecture to control the sequential operation of the entire system or a sub-portion thereof. The program-panel controller includes a first user accessible graphic program by which the system architecture can be symbolically reconfigured and a second user accessible instruction set program by which the operating parameters of the so-configured system or a sub-portion thereof may be altered.

Software architecture based on communicating residential environments

Abstract: This paper describes an alternative approach to software architecture, where the classical division of responsibilities between operating systems, programming languages and compilers, and so forth is revised. Our alternative is organized as a set of self-contained environments which are able to communicate pieces of software between them, and whose internal structure is predominantly descriptive and declarative. The base structure within each environment (its diversified shell) is designed so that it can accomodate such arriving software modules.The presentation of that software architecture is done in the context of an operational implementation, the SCREEN system (System of Communicating REsidential ENvironments).

Architecture of future data base systems

Abstract: In this paper we first discuss three typical programming interfaces which future DBMS systems may support. These interfaces are: I) non-procedural, set-oriented (relational), 2) navigational (CODASYL), and 3) access method. After briefly comparing the language levels provided by each interface, four data base system architectures are described which can support a high level interface on top of one of the other two interfaces. We believe these architectures are the only reasonable candidates for future DBMS packages.

Chapter 2. Distributed system architecture model

Abstract: We have presented a general multidimensional model for a distributed system architecture that, we believe, usefully serves to unify design issues, analysis, system organization, and should be useful in establishing standards for required interfaces. We have also introduced design goals and issues that will be discussed, along with details of useful mechanisms, further in later chapters. The central features of the model are that it emphasizes

How expert should an expert system be

Abstract: A computer system which aids computer engineers in fault diagnosis is described. The system, called CRIB (Computer Retrieval Incidence Bank) is shown to fit into the class of pattern-directed inference systems. Emphasis is placed on the "before" and "after" phases of system generation and it is shown why, to be called an expert system, these phases are important. The forms of knowledge used in CRIB are shown to be adequate for diagnosis and yet possess little of the structural or functional knowledge of more advanced expert systems. Summaries are given of the three phases of implementation: elicitation, implementation of knowledge structures, validation and improvement. The idea of an expert system as a "model of competence" is mentioned and the transferrance of the system architecture to software diagnosis, using the same model, is described. There are short discussions of system performance and the nature of expert systems.

MESSIDOR system

Abstract: MESSIDOR is an interactive information retrieval system. It differs from current systems in that it allows the simultaneous search of several bibliographic databases. The databases may be on different sites and may use different query languages (MISTRAL, QUEST,...). These local languages are invisible to the users of MESSIDOR. They are all translated to a single language. We describe MESSIDOR's goals, system architecture, user language and some details of the implementation. The system is implemented on a MICRAL 80-30 microcomputer.

A pipelined pseudoparallel system architecture for motion analysis

Abstract: Parallel processing has mostly been applied to well-defined and a priori partitioned problems, and not much has been done to introduce parallelism into serial algorithms. This paper introduces a new concept of pseudoparallelism in which the serial algorithm is partitioned into several noninteractive independent subtasks so that parallelism can be used within each subtask level. This novel approach is illustrated by taking motion analysis as an example. Complete details of such a pseudoparallel architecture with a distributed operating system (no master control) have been worked out. Problems encountered in the course of designing such a system are outlined, and necessary justifications provided. A detailed scheme indicating various memory modules, processing elements, and their data-path requirements is included, and ways to provide continuous flow of partitioned information in the form of a synchronized pipeline are described. Finally, the performance of the proposed scheme is evaluated. The basic strategy appears to be useful in designing such parallel systems for other unexplored complex problems.

Prototyping: An approach to information and communication system design

Abstract: This paper describes prototyping, a state-of-the-art methodology to assist a design team in making a through definition and analysis of new requirements, feasibility, alternative selections, workload impact, system and/or application specification, implementation, and testing. Suggested prototype tools and techniques are presented, and guidance is included to aid a design team in obtaining accurate and timely results. This paper is not intended to be a complete text on design. It should be enhanced with a design team's expertise, consultation from sources with design experience, and reference to other design literature.Prototyping is a process (the act, study, or skill) of modeling an information-communication system architecture in one or more levels of detail, using descriptive models, abstract models, and working models of the system and its component parts (synonym: archetyping).This work was completed while the author was working with prior employers.

High-Level Computer Architecture

Abstract: Associated with each programming language is a computer architecture that executes programs in that language. If the language is a low-level instruction set, the associated computer architecture is a low-level von Neumann architecture; if the language is high-level, the associated architecture is high-level. The internal structure of a high-level architecture reflects the constructs of the high-level language. The articles in this special issue deal with high-level computer architecture.

BFS—realization of a fault-tolerant architecture

Abstract: The paper considers possibilities of distributed architecture to improve the reliability of microcomputer systems to realize a fault-tolerant system. By using and extending existing redundancies of hardware, software, and time, a partially meshed ring structure that meets the requirements of a fault-tolerant architecture has been designed. Aspects of hardware implementation, system software structure, operating system requirements, fault diagnosis, and reconfiguration are explained, based on the fault-tolerant architecture basic fault-tolerant system—BFS.

Software Maintainability - What It Means and How to Achieve It

Abstract: The terms reliability and maintainability are often misunderstood in the software field since software does not `break' or `wear out' in the physical sense; it either works in a given environment or it does not. This means that the program is either right or wrong in the environment. However, it does not follow that a program that is right is reliable or maintainable. For the purposes of this paper a program is maintainable if it meets the following two conditions: ? There is a high probability of determining the cause of a problem in a timely manner the first time it occurs, and ? There is a high probability of being able to modify the program without causing an error in some other part of the program. There are three important topics in developing a program which fulfills the above criteria: documentation, standards, and system architecture. This paper discusses the third topic since it is the real key to the development of maintainable software. A particular architecture of structured modular design using controlled communication between modules is presented together with its relationship to maintainability and reliability. The benefits of this approach are: ? High isolation between modules. ? Communication visibility and monitoring. ? Error location. ? Overload control. ? Simplified control program. ? Transparency to multicomputer configurations. A method is presented for calculating maintainability parameters related to this architecture, and examples of these calculations are given and interpreted.

A VLSI Architecture for Software Structure: The Intel 8086

Abstract: By supporting modular programs and high-level languages, this microprocessor architecture aids the implementation of complex software.

VISION II: a dynamic raster-scan display

Abstract: The analog graphics display is one of the most fascinating devices that computer technology has produced. The fluidity and complexity of motion possible with line-drawing displays is quite captivating and has initiated many interesting and fruitful software endeavors.Unlike their analog counterparts, the majority of raster-scan display systems have been capable of producing only text or static imagery. Dynamic graphics on raster displays has yet to be explored thoroughly in either the hardware or software area. This paper describes a digital video display system architecture with dynamic graphics capabilities. The hardware design and implementation derives from the author's thesis work at the University of Illinois.

A general purpose data processing system simulator for satellite ground stations

Abstract: The Data Processing System Simulation for Satellite Ground Stations (DPSSGS) is designed to model a general class of Automatic Data Processing Equipment (ADPE) functions for a satellite ground control station. A typical ground station might contain ten computers with associated disks and memories and must process large quantities of data in real-time. The selection of the hardware, the design of the computer system architecture and software is a prodigious task and presents a high risk in terms of the performance and cost of the final system if adequate design data is not available early in the design process. The DPSSGS is a generic model of multi-tasking computers and computer networks and provides a design tool for analyzing the many alternate computer configurations proposed in the design of a ground station. Although the impetus for the development of the DPSSGS came from the designers of ground stations, application to a wider range of data processing systems is possible. The DPSSGS was applied extensively to the design of a recent ground station.

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

Abstract: An active controls technology (ACT) system architecture was selected based on current technology system elements and optimal control theory was evaluated for use in analyzing and synthesizing ACT multiple control laws. The system selected employs three redundant computers to implement all of the ACT functions, four redundant smaller computers to implement the crucial pitch-augmented stability function, and a separate maintenance and display computer. The reliability objective of probability of crucial function failure of less than 1 x 10 to the -9th power per flight of 1 hr can be met with current technology system components, if the software is assumed fault free and coverage approaching 1.0 can be provided. The optimal control theory approach to ACT control law synthesis yielded comparable control law performance much more systematically and directly than the classical s-domain approach. The ACT control law performance, although somewhat degraded by the inclusion of representative nonlinearities, remained quite effective. Certain high-frequency gust-load alleviation functions may require increased surface rate capability.

A General Purpose Multicomputer System Based On The Ieee S-100 Bus

Abstract: Multicomputer systems based on microprocessors have been built for several specialized applications during the past five years. This paper presents a general purpose multicomputer system based on the IEEE S-100 BUS with provisions for up to 16 computers using either 8 or 16 bit microprocessors. The system architecture provides for up to 256K Bytes of memory per computer with easy extension of the local computer bus to provide additional memory and/or 1/0 devices. The paper provides a summary of the design objectives and a review of possible applications.

Design and implementation of a portable database system for small computers

Abstract: This paper describes the design and implementation of PEDMS. Part B describes design objectives, resulting system architecture and interfaces to user and database administrator. Part C concentrates on the implementation of PEDMS, discussing the difficulties imposed by the environment, and the ways of circumventing these difficulties.