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Showing papers on "Systems architecture published in 1994"


Journal ArticleDOI
TL;DR: An Expectation-Maximization (EM) algorithm for adjusting the parameters of the tree-structured architecture for supervised learning and an on-line learning algorithm in which the parameters are updated incrementally.
Abstract: We present a tree-structured architecture for supervised learning. The statistical model underlying the architecture is a hierarchical mixture model in which both the mixture coefficients and the mixture components are generalized linear models (GLIM's). Learning is treated as a maximum likelihood problem; in particular, we present an Expectation-Maximization (EM) algorithm for adjusting the parameters of the architecture. We also develop an on-line learning algorithm in which the parameters are updated incrementally. Comparative simulation results are presented in the robot dynamics domain.

2,418 citations


Journal ArticleDOI
01 Oct 1994
TL;DR: This work surveys data modeling, querying, data structures and algorithms, and system architecture for spatial database systems, with the emphasis on describing known technology in a coherent manner, rather than listing open problems.
Abstract: We propose a definition of a spatial database system as a database system that offers spatial data types in its data model and query language, and supports spatial data types in its implementation, providing at least spatial indexing and spatial join methods. Spatial database systems offer the underlying database technology for geographic information systems and other applications. We survey data modeling, querying, data structures and algorithms, and system architecture for such systems. The emphasis is on describing known technology in a coherent manner, rather than listing open problems.

744 citations


Patent
16 Mar 1994
TL;DR: In this article, the authors propose a collaboration system that integrates separate real-time and asynchronous networks for audio and video, and the latter for control signals and textual, graphical and other data in a manner which closely approximates the experience of face-to-face collaboration.
Abstract: A collaboration system that integrates separate real-time and asynchronous networks - the former for real-time audio and video, and the latter for control signals and textual, graphical and other data - in a manner which closely approximates the experience of face-to-face collaboration. These capabilities are achieved by exploiting a variety of hardware, software and networking technologies in a manner that preserves the quality and integrity of audio/video/data and other multimedia information, even after wide area transmission, and at a significantly reduced networking cost as compared to what would be required by presently known approaches. The system architecture is readily scalable to the largest enterprise network environments. It accommodates differing levels of collaborative capabilities available to individual users and permits high-quality audio and video capabilities to be readily superimposed onto existing personal computers and workstations (12) and their interconnecting LANs (10) and WANs (15). In the case of a plurality of geographically dispersed LANs (10) interconnected by a WAN (15), the demands made on the WAN are significantly reduced by employing multi-hopping techniques, including avoiding the unnecessary decompression of data at intermediate hops, as well as video mosaicing and cut-and-paste technology.

387 citations


Proceedings ArticleDOI
21 May 1994
TL;DR: A theory is presented for one aspect of architectural description, the interactions between components, to define architectural connectors as explicit semantic entities that characterize each of the participant roles in an interaction and how these roles interact.
Abstract: As software systems become more complex the overall system structure - or software architecture - becomes a central design problem. An important step towards an engineering discipline of software is a formal basis for describing and analyzing these designs. We present a theory for one aspect of architectural description, the interactions between components. The key idea is to define architectural connectors as explicit semantic entities. These are specified as a collection of protocols that characterize each of the participant roles in an interaction and how these roles interact. We illustrate how this scheme can be used to define a variety of common architectural connectors. We provide a formal semantics and show how this lends to a sound deductive system in which architectural compatibility can be checked in a way analogous to type checking in programming languages. >

378 citations


Proceedings ArticleDOI
Alan J. Demers1, Karin Petersen1, Mike Spreitzer1, D. Ferry1, Marvin M. Theimer1, Brent B. Welch1 
08 Dec 1994
TL;DR: A fresh, bottom-up and critical look at the requirements of mobile computing applications and carefully pull together both new and existing techniques into an overall architecture that meets these requirements.
Abstract: The Bayou System is a platform of replicated, highly available, variable-consistency, mobile databases on which to build collaborative applications. This paper presents the preliminary system architecture along with the design goals that influenced it. We take a fresh, bottom-up and critical look at the requirements of mobile computing applications and carefully pull together both new and existing techniques into an overall architecture that meets these requirements. Our emphasis is on supporting application-specific conflict detection and resolution and on providing application-controlled inconsistency.

326 citations


Journal ArticleDOI
TL;DR: A general LRGF network structure is introduced that includes most of the network architectures that have been proposed to date and indicates some open issues concerning these types of networks.
Abstract: In this paper, we will consider a number of local-recurrent-global-feedforward (LRGF) networks that have been introduced by a number of research groups in the past few years. We first analyze the various architectures, with a view to highlighting their differences. Then we introduce a general LRGF network structure that includes most of the network architectures that have been proposed to date. Finally we will indicate some open issues concerning these types of networks. >

302 citations


Journal ArticleDOI
TL;DR: This paper connects both simulated and real robots to Alecsys, a parallel implementation of a learning classifier system with an extended genetic algorithm to demonstrate that classifier systems with genetic algorithms can be practically employed to develop autonomous agents.

267 citations


Book
01 Jan 1994
TL;DR: This work focuses on the development of a Reference Model for Multimedia Synchronization, and its applications in Media and Data Streams, and on the Architecture of the Multimedia Database Management System.
Abstract: Foreword Preface 1.Introduction Branch-overlapping Aspects of Multimedia. Content. Global Structure. Multimedia Literature. 2. Multimedia: Media and Data Streams. Medium. Main Properties of a Multimedia System. Multimedia. Traditional Data Stream Characteristics. Data Streams Characteristics for Continuous Media. Information Units. 3. Sound/Audio. Basic Sound Concepts. Music. Speech. 4. Image and Graphics. Basic Concepts. Computer Image Processing. Comments. 5. Video and Animation. Basic Concepts. Television. Computer-based Animation. 6. Data Compression. Storage Space. Coding Requirements. Source, Entropy, and Hybrid Coding. Some Basic Compression Techniques. JPEG. H.261 (px64). MPEG. DVI. Comments. 7. Optical Storage. History. Basic Technology. Video Disks and Other WORMs. Compact Disk Digital Audio. Compact Disk Read Only Memory. CD-ROM Extended Architecture. Further CD-ROM-based Developments. Compact Disc Write Once. Compact Disk Magneto Optical. The Prospects of CD Technologies. 8. Computer Technology. Communication Architecture. Multimedia Workstations. Comments. 9. Multimedia Operating Systems. Introduction. Real-Time. Resource Management. Process Management. File Systems. Additional Operating System Issues. System Architecture. Concluding Remarks. 10. Networking Systems. Layers, Protocols, and Services. Networks. Local Area Networks (LANs). Metropolitan Area Networks (MANs). Wide Area Networks (WANs). Comments. 11. Multimedia Communication Systems. Application Subsystem. Transport Subsystem. Quality of Service and Resource Management. Comments. 12. Data Base Systems. Multimedia Database Management System. Characteristics of an MDBMS. Data Analysis. Data Structure. Operations on Data. Integration in a Database Model. Comments. 13. Documents, Hypertext and Hypermedia. Documents. Hypertext and Hypermedia. Document Architecture SGML. Document Architecture ODA. MHEG. 14. User Interface. General Design Issues. Current Work. Extension through Video and Audio. Video at the User Interface. Audio at the User Interface. User- friendliness as the Primary Goal. Comments. 15. Synchronization. Introduction. Notion of Synchronization. Presentation Requirements. A Reference Model for Multimedia Synchronization. Synchronization. Case Studies. Comments. Summary and Outlook. 16. Abstractions for Programming. Abstraction Levels. Libraries. System Software. Toolkits. Higher Programming Languages. Object-oriented Approaches. Comments. 17. Multimedia Applications. Introduction. Media Preparation. Media Composition. Media Integration. Media Communication. Media Consumption. Media Entertainment. Trends. 18. Future Directions. Where Are We Today? What Are the Next Steps? What Are the Multimedia Research Issues? Abbreviations. Bibliography. Index.

264 citations


Journal ArticleDOI
01 Apr 1994
TL;DR: The design goals, history, and system architecture of p4 are discussed and a diverse collection of applications that have demonstrated the utility of the p4 system are described.
Abstract: p4 is a portable library of C and Fortran subroutines for programming parallel computers. It is the current version of a system that has been in use since 1984. It includes features for explicit parallel programming of shared-memory machines, distributed-memory machines (including heterogeneous networks of workstations), and clusters, by which we mean shared-memory multiprocessors communicating via message passing. We discuss here the design goals, history, and system architecture of p4 and describe briefly a diverse collection of applications that have demonstrated the utility of p4.

209 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a summary of the major technical report of the IFAC/IFIP Task Force on Architectures for Integrating Manufacturing Activities and Enterprises, and the findings generated relating to the suitability of various architectures for the integration task.

133 citations


Journal ArticleDOI
TL;DR: A novel architecture for a fault-tolerant multiprocessor environment that achieves performance of a triple modular redundant system using duplex system redundancy and requires no rollbacks for recovering from single faults is proposed.
Abstract: We propose a novel architecture for a fault-tolerant multiprocessor environment. It is assumed that the multiprocessor organization consists of a pool of active processing modules and either a small number of spare modules or active modules with some spare processing capacity. A fault-tolerance scheme is developed for duplex systems using checkpoints. Our scheme, unlike traditional checkpointing schemes, requires no rollbacks for recovering from single faults. The objective is to achieve performance of a triple modular redundant system using duplex system redundancy. >

Journal ArticleDOI
TL;DR: The architecture relies on innovative data striping and real-time scheduling to allow a large number of guaranteed concurrent accesses, and uses separation of metadata from real data to achieve a direct flow of the media streams between the storage devices and the network.
Abstract: Large scale multimedia storage servers will be an integral part of the emerging distributed multimedia computing infrastructure. However, given the modest rate of improvements in storage transfer rates, designing servers that meet the demands of multimedia applications is a challenging task that needs significant architectural innovation. Our research project, called Massively-parallel And Real-time Storage ( mars ) architecture, is aimed at the design and prototype implementation of a large scale multimedia storage server. It uses some of the well-known techniques in parallel I/O, such as data striping and Redundant Arrays of Inexpensive Disks ( raid ) and an innovative atm based interconnect inside the server to achieve a scalable architecture that transparently connects storage devices to an atm -based broadband network. The atm interconnect within the server uses a custom asic called ATM Port Interconnect Controller ( apic ) currently being developed as a part of an arpa sponsored gigabit local atm testbed. Our architecture relies on innovative data striping and real-time scheduling to allow a large number of guaranteed concurrent accesses, and uses separation of metadata from real data to achieve a direct flow of the media streams between the storage devices and the network. This paper presents our system architecture; one that is scalable in terms of the number of supported users and the throughput.

Journal ArticleDOI
TL;DR: The approach provides a solution to build systems whose on-line behavior is checked against a formal model derived from a formal description, which is a formal and verified model of some adequately selected aspects of the system behavior.
Abstract: Proposes the observer concept for designing self-checking distributed systems, i.e. systems that detect erroneous behaviors as soon as errors act at some observable output level. The approach provides a solution to build systems whose on-line behavior is checked against a formal model derived from a formal description. In other words, the actual implementation is continuously checked against a reference, this reference being a formal and verified model of some adequately selected aspects of the system behavior. The corresponding methodology, the software concepts and some applications of the observer are presented. General definitions are given first that theoretically define self-checking systems as systems that include and implement complete on-line validation. The basic concepts and the difficulties to implement self-checking validation are then given. In order to provide simple implementations, the previous definitions are weakened to design quasi-self-checking observers for LANs using a broadcast service. Three specific applications are given to illustrate the proposed approach: testing a virtual ring MAC protocol, checking the link and transport layers in an industrial LAN, and managing a complete OSI layering, from layer 2 to layer 6, in an open system architecture. >

Proceedings ArticleDOI
01 Jan 1994
TL;DR: The SGI Challenge system architecture provides a high-bandwidth, low-latency cache-coherent interconnect for several high performance processors, I/O busses, and a scalable memory system.
Abstract: This paper presents the architecture, implementation, and performance results for the SGI Challenge symmetric multiprocessor system. Novel aspects of the architecture are highlighted, as well as key design trade-offs targeted at increasing performance and reducing complexity. Multiprocessor design verification techniques and their impact is also presented. The SGI Challenge system architecture provides a high-bandwidth, low-latency cache-coherent interconnect for several high performance processors, I/O busses, and a scalable memory system. Hardware cache coherence mechanisms maintain a consistent view of shared memory for all processors, with no software overhead and minimal impact on processor performance. HDL simulation with random, self checking vector generation and a lightweight operating system on full processor models contributed to a concept to customer shipment cycle of 26 months. >

Proceedings ArticleDOI
01 Nov 1994
TL;DR: This work proposes both hardware and software structures that permit efficient handling of synchronous exceptions by user-level code that reduces exception-delivery cost by an order ofmagnitude on current RISC processors, and shows the performance benefits of that mechanism for several example applications.
Abstract: Program-synchronous exceptions, for example, breakpoints, watchpoints, illegal opcodes, and memory access violations, provide information about exceptional conditions, interrupting the program and vectoring to an operating system handler. Over the last decade, however, programs and run-time systems have increasingly employed these mechanisms as a performance optimization to detect normal and expected conditions. Unfortunately, current architecture and operating system structures are designed for exceptional or erroneous conditions, where performance is of secondary importance, rather than normal conditions. Consequently, this has limited the practicality of such hardware-based detection mechanisms.We propose both hardware and software structures that permit efficient handling of synchronous exceptions by user-level code. We demonstrate a software implementation that reduces exception-delivery cost by an order-of-magnitude on current RISC processors, and show the performance benefits of that mechanism for several example applications.

Journal ArticleDOI
TL;DR: The paper refines the definition of IS architecture and puts it into broader perspective by defining a set of concrete, thus more manageable sub-architectures: process, data, control and technology architectures.

Journal ArticleDOI
TL;DR: This paper examines the fundamental problems that one faces when testing a distributed, hard real-time system and identifies six such fundamental problems: Organization, Observability, Reproducibility, Host/Target Approach, Environment Simulation, and Representativity.
Abstract: This paper examines the fundamental problems that one faces when testing a distributed, hard real-time system. It specifically identifies the influences of the distributedness and of the real-time requirements of the systems considered. We show how the usual problems of testing become more difficult, and which additional problems are introduced, because of these additional system characteristics.

Journal ArticleDOI
TL;DR: In this article, a multi-agent architecture for dynamic scheduling is presented, where the flexibility of the architecture both from the organizational point of view and from the control one is supported by the negotiation technique.
Abstract: This paper addresses a multi-agent architecture for dynamic scheduling. The flexibility of the architecture both from the organizational point of view and from the control one is supported by the negotiation technique. The need for integration, the use of standards and information modelling are emphasized. Combining a distributed architecture with an integration of the scheduling and control functionalities flexibility is increased, especially when disruptions take place. Finally, some conclusions and implementation aspects are presented.

Journal ArticleDOI
TL;DR: The paper narrates how the lengthy and difficult conceptual work created a foundation of knowledge and experience which in turn produced an “explosion” of numerous prototypes, and tries to elaborate on the effort it takes to convert prototypes into marketable products.

Patent
07 Oct 1994
TL;DR: The Communications Management System architecture (CMS) as mentioned in this paper supports asset, frequency and key management functions in a multi-unit, multi-network communications system and automates the planning required for effectively carrying out tactical communications in such an environment.
Abstract: A novel Communications Management System architecture (CMS) supports asset, frequency and key management functions in a multi-unit, multi-network communications system and automates the planning required for effectively carrying out tactical communications in such an environment. CMS matches the detailed frequency and key distribution required for radio networks supporting such an operation, and consolidates all of the information required to operate such a radio system into a single database. The CMS architecture provides a flexibility to allow for specialized key and frequency assignment generation, net communications planning, distribution planning of communication equipment, deployment planning and asset planning and generation of Communications Information (CI). The architecture provides an integrated approach that enables such communication planning/management functions to be tied together into a single software program to assure verification of data and eliminate duplication of effort.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the anticipated future requirements of an advanced control for metal cutting machine tools; of particular interest is the integration of process monitoring and optimization with the normal processes of interpolation and axis control.
Abstract: The authors discuss in detail the anticipated future requirements of an advanced control for metal cutting machine tools; of particular interest is the integration of process monitoring and optimization with the normal processes of interpolation and axis control. A detailed discussion of the philosophy underlying the development of the UBC open architecture machine tool controller and its current capabilities is also presented.

Patent
17 Mar 1994
TL;DR: In this paper, a hardware simulation model simulating the I/O device behavior is presented as follows: an internal connection analysis table and a definition table defining various system architectures are prepared from the H/W specification information and the subsystem definition table are related to each other to prepare the specification description of system architecture.
Abstract: Test environmental programs are prepared using the following steps: Upon application of H/W specification information containing information on the system architecture, a guidance is displayed based on the H/W specification information and the user is caused to input subsystem definition information. The H/W specification information and the subsystem definition table are related to each other to prepare the specification description of system architecture, which is used together with the simulator in a simulator library to generate test environment programs according to a testee designation. In the application-specific hardware simulator, a hardware simulation model simulating the I/O device behavior is prepared as follows: An internal connection analysis table and a definition table defining various system architectures are prepared from the hardware description information describing the I/O device hardware specification in the specification description language. An external I/O interface definition table is thus prepared from an I/O device hardware specification, an interface routine for data conversion between the I/O device and the application-specific hardware simulator and information from the user for designating the correspondence between the I/O device and the interface routine. These various tables are used to generate a source program for the hardware simulation model.

Journal ArticleDOI
Petra Perner1
01 Sep 1994
TL;DR: The architecture of such a complex knowledge-based inspection system used for defect recognition and misprint diagnosis in offset printing is described, and an object-oriented concept and task-dependent algorithms for efficient image processing are implemented.
Abstract: Combining knowledge-based processing with image processing is a key issue in the future of the visual inspection of complex patterns such as offset prints. Often the class of the defect determines the state of the process, which must known for eliminating the cause of the defect. We describe the architecture of such a complex knowledge-based inspection system. The system has been used for defect recognition and misprint diagnosis in offset printing, but it is flexible enough for other applications. The system is based on a set of general and powerful tools for the knowledge interpretation of sensor signals. An object-oriented concept and task-dependent algorithms for efficient image processing are implemented. The paper concentrates on four points: integration of the system in the offset printing process, a description of the system architecture, knowledge acquisition, and implementation results.

Proceedings ArticleDOI
15 May 1994
TL;DR: This paper presents an approach of extending the data model of an object-oriented database system by means of schedules which allow for the description of the temporal characteristics of multimedia operations as they occur when modeling time-dependent data like audio and video.
Abstract: Advanced applications in fields like electronic publishing and telecooperation face the problem of handling multimedia information. Conventional database systems do not offer adequate support for storage management as they do not provide for the modeling, indexing, and manipulation of multimedia data. Database management systems need to be extended if they should be able to handle multimedia information like audio and video. In this paper we present an approach of extending the data model of an object-oriented database system by means of schedules which allow for the description of the temporal characteristics of multimedia operations as they occur when modeling time-dependent data like audio and video. First, we present a model of schedules and define the basic concepts and semantics to execute time-dependent operations. Second, we introduce the specification language as an extension to the VODAK Model Language and illustrate the concepts by examples. Finally, we briefly discuss the impact of integrating multimedia data modeling support into a database management system on the system architecture. >

Proceedings ArticleDOI
07 Dec 1994
TL;DR: The Naval Postgraduate School, SARCOS Inc., and University of Pennsylvania, under Army Research Laboratory sponsorship, demonstrated the insertion of a fully articulated human figure into a DIS environment.
Abstract: Most distributed interactive simulation (DIS) technology demonstrated in recent years has focused on vehicle interaction. The dismounted infantryman-the individual soldier-has been largely ignored or represented by static models. In six weeks of development, the Naval Postgraduate School, SARCOS Inc., and University of Pennsylvania, under Army Research Laboratory sponsorship, demonstrated the insertion of a fully articulated human figure into a DIS environment. This paper describes the system architecture. >

Proceedings ArticleDOI
05 Aug 1994
TL;DR: An outline of the TECHDOC system architecture is given and some recent developments in the project are discussed: the addition of actual event simulation in the KB, steps towards a document authoring tool, and a multimodal user interface.
Abstract: TECHDOC is an implemented system demonstrating the feasibility of generating multilingual technical documents on the basis of a language-independent knowledge base. Its application domain is user and maintenance instructions, which are produced from underlying plan structures representing the activities, the participating objects with their properties, relations, and so on. This paper gives a brief outline of the system architecture and discusses some recent developments in the project: the addition of actual event simulation in the KB, steps towards a document authoring tool, and a multimodal user interface.

Proceedings ArticleDOI
Hiemstra1
01 Jan 1994
TL;DR: A general approach to stock market prediction is presented and an architecture of a fuzzy logic forecasting support system is introduced that supports easy modification of the knowledge base, facilities to trace problem solving, and simulation.
Abstract: Interviews with portfolio managers suggests that a stock market forecasting support system should have a general model, which the users can refine to match their personal needs and beliefs The model should offer interactive problem solving and justification of its conclusion, and be able to process expert knowledge which is typically uncertain and vague. Fuzzy logic is capable of storing uncertain and vague knowledge and providing a declarative, interactive and explanatory prediction. Potential benefits of a fuzzy logic forecast support are: better decision making due to the model-based approach, knowledge management, and knowledge accumulation. The paper presents a general approach to stock market prediction and introduces an architecture of a fuzzy logic forecasting support system. The system architecture supports easy modification of the knowledge base, facilities to trace problem solving, and simulation. Evaluation of the implementation demonstrates the system's functionality. >

Proceedings ArticleDOI
21 May 1994
TL;DR: Concrete examples of what is now possible when architectural principles are applied to industrial problems in systematic ways are provided, and the potential impact of software architecture over the next few years is considered.
Abstract: Whatever the long-term impact of software architecture may turn out to be, an appropriate starting point is a concrete appraisal of the current state of the practice in the use of software architecture. It is the purpose of the article to take a step in this direction. It provides concrete examples of what is now possible when architectural principles are applied to industrial problems in systematic ways, considers the potential impact of software architecture over the next few years, and suggests steps that should be taken to bring this about. >

Journal ArticleDOI
TL;DR: This work presents a new systolic architecture that embodies the Cooley-Tukey algorithm, and requires a smaller number of processors and a small number of memory cells than other recent implementations, as well as having all the advantages of syStolic arrays.
Abstract: The use of the Cooley-Tukey algorithm for computing the 1-d FFT lends itself to a particular matrix factorization which suggests direct implementation by linearly-connected systolic arrays. Here we present a new systolic architecture that embodies this algorithm. This implementation requires a smaller number of processors and a smaller number of memory cells than other recent implementations, as well as having all the advantages of systolic arrays. For the implementation of the decimation-in-frequency case, word-serial data input allows continuous real-time operation without the need of a serial-to-parallel conversion device. No control or data stream switching is necessary. Computer simulation of this architecture was done in the context of a 1024 point DFT with a fixed point processor, and CMOS processor implementation has started. >

Proceedings ArticleDOI
01 Mar 1994
TL;DR: Starting from general requirements on configuration systems, a language based on an extension of the constraint satisfaction problem (CSP) model is developed, which allows a simple system architecture, and a declarative description of the different types of configuration knowledge.
Abstract: The COCOS (COnfiguration through COnstraint Satisfaction) project was aimed at producing a tool that could be used for a variety of configuration applications Traditionally, representation methods for technical configuration have focused either on reasoning about the structure of systems or the quantity of components, which is not satisfactory in many target areas that need both Starting from general requirements on configuration systems, we have developed a language based on an extension of the constraint satisfaction problem (CSP) model The constraint-based approach allows a simple system architecture, and a declarative description of the different types of configuration knowledge We briefly discuss the current implementation and the experiences obtained with a real-world knowledge base >