23 research outputs found
GUIDELINES FOR THE DESIGN OF ENHANCED, COST EFFECTIVE NETWORKS IN A MANUFACTURING ENVIRONMENT
Investigations into the transmission of real-time interactive speech over local area
networks (LAN) in an industriai/commerciai environment to eventually obviate the
need for a private automatic branch exchange and ultimately prepare the way for a
single interactive integrated information system (PS) that provides work stations, which
are networked via a LAN, with a fully interactive speech and graphics facility
commensurate with the future requirements in computer integrated manufacturing
(CIM).
The reasons for conducting this programme of research were that existing LANs do not
offer a real time interactive speech facility. Any verbal communication between
workstation users on the LAN has to be carried out over a telephone network (PABX).
This necessitates the provision of a second completely separate network with its
associated costs. Initial investigations indicate that there is sufGcient capacity on
existing LANs to support both data and real-time speech provided certain data packet
delay criteria can be met.
Earlier research work (in the late 1980s) has been conducted at Bell Labs and MIT.
[Ref 25, 27 & 28], University of Strathclyde [Ref 24] and at BTRL [Ref 22 and 37].
In all of these cases the real time implementation issues were not fijlly addressed. In
this thesis the research work reported provides the main criteria for the implementation
of real-time interactive speech on both existing and newly installed networks.
With such enhanced communication facilities, designers and engineers on the shop
floor can be projected into their suppliers, providing a much greater integration
between manufacturer and supplier which will be beneficial as Concurrent and
Simultaneous Engineering Methodologies are further developed.
As a result, various LANs have been evaluated as to their suitability for the
transmission of real time interactive speech. As LANs, in general, can be separated
into those with either deterministic or stochastic access mechanisms, investigations were
carried out into the ability of both the:
(i) Token Passing Bus LANs supporting the Manufacturing and
Automation Protocol (MAP)—Deterministic
and
(u) Carrier Sense Multiple Access/Collision Detection (CSMA/CD) LANs
supporting the Technical Office Protocol (TOP)— Stochastic
to support real time interactive speech, as both are used extensively in commerce and
manufacturing.
The thesis that real time interactive speech can be transmitted over LANs employed in
a computer integrated manufacturing environment has to be moderated following the
tests carried out in this work, as follows:-
The Token Passing LAN presents no serious problems under normal
traffic conditions, however, the CSMA/CD LAN can only be used in
relatively light traffic conditions i.e. below 30% of its designed
maximum capacity, providing special arrangements are made to
minimise the access, transmission and processing delays of speech
packets.
Given that a certain amount of delay is inevitable in packet switched systems (LANs),
investigations have been carried out into techniques for reducing the subjective efifect
of speech packet loss on real-time interactive systems due to the unacceptable delays
caused by the conditions mentioned above
High efficiency, character-oriented, local area networks
Imperial Users onl
Hybrid Network for Business and Information Systems
Local Area Networks provide a way of linking together computers for the purpose of sharing resources such as information, communication, high-speed printing facilities, etc., within a small area or over a complete site. Computer networks for Information Systems are available in a number of different topologies utilizing different technologies. The main criterion for network use is that the networks are inexpensive to implement. The networks available range from dedicated networks with the main type of workstation designed for a single off ice environment (but also providing interface for the more popular personal computers), to third party networks designed to connect different networks over a large area. The purpose of this thesis is both to design and to simulate a medium accessing technique for a local network. The thesis highlights some of the other medium accessing techniques available, the topologies used in these techniques, and their advantages and disadvantages. The first chapter defines the problem and briefly proposes a solution to the problem. The second chapter puts the computer network into perspective by looking at different networks. The third and fourth chapters cover the design of the Network Architecture and the Network Manager respectively. Chapter five briefly describes the Data Architecture which was implemented at Business and Economics Research, Oklahoma State University. Results of the simulation conducted are discussed in chapter six of this thesis. Appendix-A provides the figures required in understanding the thesis. Figure (3), and Figures (4, 5 & 10) are referenced from [1] and [5] respectively. Appendix-B is a glossary of all important terms used in writing this thesis.Computing and Information Science
Digital imaging technology assessment: Digital document storage project
An ongoing technical assessment and requirements definition project is examining the potential role of digital imaging technology at NASA's STI facility. The focus is on the basic components of imaging technology in today's marketplace as well as the components anticipated in the near future. Presented is a requirement specification for a prototype project, an initial examination of current image processing at the STI facility, and an initial summary of image processing projects at other sites. Operational imaging systems incorporate scanners, optical storage, high resolution monitors, processing nodes, magnetic storage, jukeboxes, specialized boards, optical character recognition gear, pixel addressable printers, communications, and complex software processes
Space station data system analysis/architecture study. Task 2: Options development, DR-5. Volume 2: Design options
The primary objective of Task 2 is the development of an information base that will support the conduct of trade studies and provide sufficient data to make key design/programmatic decisions. This includes: (1) the establishment of option categories that are most likely to influence Space Station Data System (SSDS) definition; (2) the identification of preferred options in each category; and (3) the characterization of these options with respect to performance attributes, constraints, cost and risk. This volume contains the options development for the design category. This category comprises alternative structures, configurations and techniques that can be used to develop designs that are responsive to the SSDS requirements. The specific areas discussed are software, including data base management and distributed operating systems; system architecture, including fault tolerance and system growth/automation/autonomy and system interfaces; time management; and system security/privacy. Also discussed are space communications and local area networking