作者：
Huignard, J.P.THOMSON-CSF
Laboratoire Central de Recherches Domaine de Corbeville B.P. 10 Orsay91401 France
Advantages of using optical wavelengths for informationstorage and processing has been widely discussed in the last few years and extensive research work has been done on optical memory sys terns and storage medium be...
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Advantages of using optical wavelengths for informationstorage and processing has been widely discussed in the last few years and extensive research work has been done on optical memory sys terns and storage medium because powerful coherent sources are now available and allow theoritically a diffraction limited storage density. Several laboratories have already demonstrated potential capabilities of optical systems coinpared to magnetic technology but it now appears clearly that, optical memories sys tern will only find a place in the hierarchy of storage systems used to day if they will courpete in capacity, acess speed, and very inportant in cost per bit of stored information. Considering these requirements, the "optical Videodisc" is a pood example of a cheap read only opticalstorage sys tern providing 10 bits capacity, nearly diffraction limited-storage density and video recording and readout bandwidth. Two main principles of opticalstorage techniques have been considered up to now : bit oriented memories provinding sequential acces to the storage medium ; page organized holographic memories provinding parallel writing and readout and microsecond random access speed by laser beam deflection. Each of these principles were applied to permanent storage media such as photographic plates or photopolymers materials but many attemps are actually made in the field of read-write optical memories which need erasable photosensitive materials ; Thermomagnetic ; Thermoplastic ; Photoretractive materials are the most attractive candidates for read-write systems which are actually mainly limited by the storage material performances
These three volumes contain 243 papers which are devoted to communications technology. Some topics covered include: social consequences of improved communications, digital implementation of modems, antennas, broadband...
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These three volumes contain 243 papers which are devoted to communications technology. Some topics covered include: social consequences of improved communications, digital implementation of modems, antennas, broadband terminal equipment, digital transmission systems, advances in switching network theory, phase locked loops, millimeter waveguides, propagation and communication, distributing frames, communication needs of developing nations, electronic mail systems, digital microwave systems, telephone test equipment, computer network protocols, earth terminals for communications, digital network timing and synchronization, telecommunication-transportation interactions, mobile telephony, remotely accessed data files, international digital microwave systems, interactive data systems, speech signal processing, economic analysis for loop plant, control of digital communications, networks, digital echo suppressors, electromagnetic compatibility, computer communication networks, geophysical data processing, optical fiber communications, and image bandwidth compression.
The 71 papers contained in this volume deal with such topics as: advances in coding theory, satellite systems control and telemetry, telemetry for health sciences, communication theory, applications of coding to telem...
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The 71 papers contained in this volume deal with such topics as: advances in coding theory, satellite systems control and telemetry, telemetry for health sciences, communication theory, applications of coding to telemetry, digital and analog storage, telemetry and data worldwide communications, computer communications, space communications, advances in devices and instruments, current technology of PCM data recording and recovery, computer control and telemetry, European space communications, and microprocessors for industrial telemetry.
These three volumes contain 243 papers which are devoted to communications technology. Some topics covered include: social consequences of improved communications, digital implementation of modems, antennas, broadband...
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These three volumes contain 243 papers which are devoted to communications technology. Some topics covered include: social consequences of improved communications, digital implementation of modems, antennas, broadband terminal equipment, digital transmission systems, advances in switching network theory, phase locked loops, millimeter waveguides, propagation and communication, distributing frames, communication needs of developing nations, electronic mail systems, digital microwave systems, telephone test equipment, computer network protocols, earth terminals for communications, digital network timing and synchronization, telecommunication-transportation interactions, mobile telephony, remotely accessed data files, international digital microwave systems, interactive data systems, speech signal processing, economic analysis for loop plant, control of digital communications, networks, digital echo suppressors, electromagnetic compatibility, computer communication networks, geophysical data processing, optical fiber communications, and image bandwidth compression.
advances in the technology and organization of telecommunication systems now taking place in the United Kingdom, in common with other highly industrialized countries, will significantly affect the future of telecommun...
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advances in the technology and organization of telecommunication systems now taking place in the United Kingdom, in common with other highly industrialized countries, will significantly affect the future of telecommunications. Typical of these are new and large information handling capacity transmission media of very wide bandwidth such as waveguides and optical fibers exploiting pulsecode modulation (PCM) digital techniques, computer controlled switching systems using digital time-division switches, large-scale integrated (LSI) circuits, high-capacity and fast access memory devices, and new types of solid-state visual display and image sensing devices. These technological advances will not only contribute to the growth and improvement of telephone service, they will also make possible and economic a number of new telecommunication services such as fast data and facsimile transmission (including an electronic mail delivery service), conference television, videophones, and visual display (data access) information services. They could also enhance the range of entertainment sound and television services available in the home, and provide audio/visual services for education and community purposes via broad-band local distribution networks. These technological and system advances may well have significant social implications. Although the rate at which demand for the new services will develop is uncertain, the falling cost of electronics, the rising cost of energy, time and physical transport, the increasing size of the information handling sector of the economy, and the increasing share of business and household expenditure being devoted to communications, all point to an important long-term future for the new services. Whilst the operations of a telecommunications administration need to be based on economic market demand, there may well be significant social considerations with regard to some sections of the community, e.g., the poor, the handicapped, and the old, tha
The paper outlines the general systems aspects and the organisation of nonmechanical optical memories and discusses technical advances with regard to relevant components, their implementation and the state of the art ...
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The paper outlines the general systems aspects and the organisation of nonmechanical optical memories and discusses technical advances with regard to relevant components, their implementation and the state of the art of this technology. Two basic system concepts are discussed: localized opticalstorage, and holographic storage. Two integrated techniques for optical memories are described: a page composer for holographic storage, and a new magnetooptic material for opticalstorage which uses ion milling of iron garnet to produce 10 multiplied by 10 mu m**2 storage cells 5. 5 mu m thick ″islands″ separated by 10 mu m wide, 5. 5 mu m deep grooves. Each ″island″ is switchable individually with respect to its magnetization. Expected performance features are compared with those of alternative technologies, including conventional magnetic systems, semiconductors and magnetic bubbles.
The 1975 SMPTE Equipment Exhibit was the largest our Society has ever held, with some 160 booths housing 110 exhibitors. Noteworthy was the increase in the amount of video equipment shown (as compared to even two year...
The 1975 SMPTE Equipment Exhibit was the largest our Society has ever held, with some 160 booths housing 110 exhibitors. Noteworthy was the increase in the amount of video equipment shown (as compared to even two years ago). Among the types of equipment shown were compact cameras and recorders intended for Electronic Newsgathering (IVC, RCA, Sony, Toshiba); editing control systems for helical scan ENG tapes in the U-Matic cartridge format (Convergence Corp., National Video Corp., Sony, Television Research International); compact time-code generator using the SMPTE-sponsored time code (TRI); high-quality production video recording equipment and accessories (Ampex, IVC); an exceptionally compact frame-storage video signal synchronizer (Quantel); and high-quality telecine equipment, including a new 35mm high-speed film projector, a 16mm cartridge film projector, and a state-of-the-art telecine chain with automatic color-balance control (RCA). — An outstanding application of electronic technology to motion-picture technique was seen in the Cinema Product Cinevid system. Here, an extremely small TV camera is used to provide what could be called an electronic viewfinder for a film camera. — The variety of film-editing equipment at the show indicated a high degree of mechanical and optical sophistication and a tendency toward multi-plate and multi-screen operation. — Of the motion-picture equipment on exhibit, there was a significant amount of super-8 hardware in evidence. Although much of this was not new equipment, it had not appeared previously at SMPTE shows. For this reason, we have collected the super-8 equipment in a special category below. — The information for this report was gathered from a variety of sources. Many of the exhibitors were helpful in supplying technical data and summaries about their products. And a number of members attending the conference took the time to give us their opinions on the show. We are grateful for their help and will look for it aga
Recent advances in reversible opticalstorage materials compatible with low-cost semiconductor lasers have led to experiments on high-areal-density high-data-rate opticalstorage of digital data. The results of these ...
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Recent advances in reversible opticalstorage materials compatible with low-cost semiconductor lasers have led to experiments on high-areal-density high-data-rate opticalstorage of digital data. The results of these experiments indicate that areal-densities of 10**8 bits/in**2 (1. 6 multiplied by 10**7 bits/cm**2) and data-rates from 10-25 Mbits/sec appear feasible. This, together with an improved high-track-density beam servo scheme, allows a high-capacity (1G Byte/surface) optical file to be configured using 14 inch diameter disk technology.
Recent advances in reversible opticalstorage materials compatible with low-cost semiconductor lasers have led to experiments on high-areal-density high-data-rate opticalstorage of digital data. The results of these ...
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Recent advances in reversible opticalstorage materials compatible with low-cost semiconductor lasers have led to experiments on high-areal-density high-data-rate opticalstorage of digital data. The results of these experiments indicate that areal-densities of 10**8 bits/in**2 (1. 6 multiplied by 10**7 bits/cm**2) and data-rates from 10-25 Mbits/sec appear feasible. This, together with an improved high-track-density beam servo scheme, allows a high-capacity (1G Byte/surface) optical file to be configured using 14 inch diameter disk technology.
New technology is always evolving and companies must have appropriate security for their business to be able to keep up-to-date with the changes. With the rapid growth in internet and www facilities, database secur...
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ISBN:
(数字)9780387355641
ISBN:
(纸本)9780792384885;9781475749144
New technology is always evolving and companies must have appropriate security for their business to be able to keep up-to-date with the changes. With the rapid growth in internet and www facilities, database security will always be a key topic in business and in the public sector and has implications for the whole of society.;covers issues related to security and privacy of information in a wide range of applications, including:;This book contains papers and panel discussions from the Twelfth Annual Working conference on database Security, organized by the International Federation for Information Processing (IFIP) and held July 15-17, 1998 in Chalkidiki, Greece.;will prove invaluable reading for faculty and advanced students as well as for industrial researchers and practitioners working in the area of database security research and development.
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