The structures for the storage of data in CAD systems influence to a large extent the effectiveness of the system. This paper reviews the wide range of data structures and database management systems (DBMS) available ...
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The structures for the storage of data in CAD systems influence to a large extent the effectiveness of the system. This paper reviews the wide range of data structures and database management systems (DBMS) available for structuring CAD data. Examples of basic data types are drawn from the MODULA-2 language. The relationship between these basic data types, their composite structures and the classical data models (on which many DBMS are based) is discussed, and the limitations of existing DBMS in modelling CAD data highlighted. A set of requirements for CAD database management systems is drawn up and the emerging role of product models (which seek to encapsulate the totality of data elements required to define fully an engineering artefact) is explored. Copyright (C) 1996 Civil-Comp Limited and Elsevier Science Limited.
Technical developments in the past few decades have led to scanners with greater accuracy and higher frequencies of operation at larger scan angles with wider apertures. The causes of this evolution of galvanometric a...
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ISBN:
(纸本)0819417300
Technical developments in the past few decades have led to scanners with greater accuracy and higher frequencies of operation at larger scan angles with wider apertures. The causes of this evolution of galvanometric and resonant scanners, whose attributes make sophisticated applications possible, are given in order to anticipate future requirements and technologies for the next generation of these scanning devices.
To develop new high density opticaldatastorage, we have studied near field optical microprobe array of waveguide mode, including the design optimization of microprobe structure, fabrication using micro-fabrication p...
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During the past years, the limited access-times and memory bandwidth in electronic random-access memory (RAM) has triggered a concerted research effort towards deploying optical memory circuitry for exploiting the inh...
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During the past years, the limited access-times and memory bandwidth in electronic random-access memory (RAM) has triggered a concerted research effort towards deploying optical memory circuitry for exploiting the inherent high-bandwidth characteristics of light-based technologies. Yet the deployment of optical memory elements in functional optical RAM demonstrations has still been limited to single-bit capacity levels, with the few multi-bit demonstrations still offering only storage functionality without any true random-access capabilities. In this article, we demonstrate an experimental 16-bit all-optical RAM bank prototype that follows a 4 x 4 matrix organization and supports addressable random access storage of four 4-bit WDM-formatted opticaldata Words at a 20 Gb/s memory-throughput. The proposed architecture constitutes of completely passive Row/Column decoding (RD/CD) subsystems, four Semiconductor optical Amplifier Mach-Zehnder Interferometer (SOA-MZI) Access Gates (AGs) for enabling the access towards the 4 available Word Lines (WLs) and 16 all-optical Flip-Flops (AOFF) arranged in a 4 x 4 RAM bank. Each FF is incorporated in an indicative photonic integrated circuit (PIC). The experimental validation of the complete 16-bit RAM bank reveals error-free operation in Write mode with a peak power penalty between 8.3-10.2 dB at 10(-9) bit-error-rate (BER) measurements, indicating a roadmap for two-dimensional addressable (2D) RAM banks that can penetrate the optical computing application domain.
To create and utilize a strong Light source with sub-wavelength size has opened up a new frontier in optics, the near-field optics, One of the most attractive applications of the near-field optics is near-field optica...
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To create and utilize a strong Light source with sub-wavelength size has opened up a new frontier in optics, the near-field optics, One of the most attractive applications of the near-field optics is near-field opticaldatastorage, The optical memory with high density and high data transfer rate is highly demanded to utilize an array of high throughput nano-scaled light sources for writing and reading bits on a medium. In this paper. we propose a hybrid structure of vertical cavity surface emitting laser (VCSEL) and aperture array for optical near-field memory head, namely VCSEL/NSOM. A technological solution for fabrication of the aperture array with Si micromachining technology is presented. An investigation of the optical performance of the near-field light at the apertures of the Si micromachined aperture array is presented. The primary result of writing and reading bits on a phase change (PC) medium using the fabricated structure is demonstrated. (C) 2002 Elsevier Science B.V. All rights reserved.
We introduced an inorganic electrochromatic layer for layer selection recordable optical disk (LS-R) by applying voltage. The material showed a large transmittance change in a wide wavelength range. The cross-talk bet...
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opticaldatastorage is now well into the second decade of continuing market and technology expansion. Media removability, whish is the main attribute of this technology, presented the optical recording industry with ...
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ISBN:
(纸本)0819437204
opticaldatastorage is now well into the second decade of continuing market and technology expansion. Media removability, whish is the main attribute of this technology, presented the optical recording industry with unmatched opportunities and also new challenges. On the one hand, data interchange between the media and drives from different sources becomes a major concern, which can only be solved if international standards for all optical recording disk/cartridge are available. Many standards organizations, with the help of world wide industrial support, took up the challenge, and numerous international standards were established which are now being adapted. One the other hand, copy protection technology must be developed to prevent illegal copying and distribution of contents using this removable media. This need is accentuated by the proliferation of low cost CD and now DVD disks replication means and the availability of recordable and rewritable CD and DVD devices. This paper provides an update of the brief summary of the current status of the international optical disk standards published ealier(1) and a breif review of the copy protection technology.
This conference proceedings contains 5 papers. The main subjects are optical disc storagetechnology, compact image storage by computers, electronically scanned micrographs, the recording and provision of image data f...
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This conference proceedings contains 5 papers. The main subjects are optical disc storagetechnology, compact image storage by computers, electronically scanned micrographs, the recording and provision of image data for satellites, and storage and retrieval of facial images.
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