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关键词： 唯一标识符   解析系统  

摘要： 分析对比了现有的一些标识符背后所采用的各种解析机制，随后以其中较为优秀的 Handle System为主要对象分析了其名称空间的构成、服务体系结构、唯一标识符管理和 解析的服务原理以及Handle System协议。最后简要介绍了基于Handle System的唯一标 识符系统在国内的实验部署情况。

关键词： 网络互连   开放式系统   OSI   信息技术   数据处理   信息交流   信息交换   定义   对象   ASN.1   注册   题名  

标准号: ISO/IEC 9834-8-2005

摘要： This Recommendation | International Standard specifies the format and generation rules that enable users to produce 128-bit identifiers that are either guaranteed to be globally unique, or are globally unique with a high probability. The UUIDs generated in conformance with this Recommendation | International Standard are suitable either for transient use, with generation of a new UUID every 100 nanoseconds, or as persistent identifiers. This Recommendation | International Standard is derived from earlier non-standard specifications of UUIDs and their generation, and is technically identical to those earlier specifications. This Recommendation | International Standard specifies the procedures for the operation of a Web-based Registration Authority for UUIDs. This Recommendation | International Standard also specifies and allows the use of UUIDs (registered or not registered) as OID components under the arc {joint-iso-itu-t uuid(25) }. This enables users to generate OIDs without any registration procedures. This Recommendation | International Standard also specifies and allows the use of UUIDs (registered or not registered) to form a URN.

关键词： 数字资源唯一标识符   发展战略   数字图书馆建设   异构数据库   方法  

关键词： 注册   定义   数据处理   开放系统互连   客体   信息技术   信息交换   作标记   网络互连  

标准号: ISO/IEC 9834-3-2005

摘要： This Recommendation | International Standard specifies the procedures for operating the International Registration Authority for assignment of values to ASN.l object identifier arcs beneath the top-level arc jointly administered by ISO and ITU-T.

关键词： 程序规则   识别   注册   ASN.1   规程   开放系统互连   信息交流   数据处理   信息交换   定义   网络互连   数据交换   OSI   信息技术  

标准号: ISO/IEC 9834-1-2005

摘要： This Recommendation | International Standard: a) specifies a Registration-Hierarchical-name-tree (RH-name-tree) which is a generic tree structure for allocations made by Registration Authorities, and the ASN.l object identifier tree which is a specific instance of the RH-name-tree; b) registers the three top-level arcs of the ASN. 1 object identifier tree; c) specifies procedures which are generally applicable to registration in the context of an RH-name-tree; d) provides guidelines for the establishment and operation of International Registration Authorities; e) provides guidelines for additional Recommendations | International Standards which choose to reference the procedures in this Recommendation | International Standard. NOTE 1 - This Recommendation | International Standard does not exclude or disallow the use of any syntactic forms of names or any naming domains for registration purposes provided that the domains ensure non-ambiguity within their scope. This Recommendation | International Standard is intended to cover those cases where the registration-hierarchical-name is appropriate. NOTE 2 - Information about registration for specific objects is contained in separate Recommendations | International Standards. This Recommendation | International Standard applies to registration by Recommendations | International Standards, by International Registration Authorities, and by any other Registration Authority.

标准号: BS EN ISO 19112-2005

关键词： 表   图书馆学与情报学   文献目录   参考文献   文献描述   定义   自动计数系统   文献   文献工作   术语  

标准号: BS ISO 12615-2004

摘要： This International Standard applies to the recording, storing and exchange of information on bibliographic sources for terminological work and terminography. It specifies the data elements to be included in bibliographic references for terminology work. These references can be used as data categories in computer applications in terminology or in presenting bibliographies and lists of references accompanying other textual matter, and citations in journal articles. This International Standard does not apply to bibliographic descriptions that record and identify documents and are used by librarians, bibliographers and indexers. This International Standard also describes source identifiers for different types of bibliographical references and their use. It indicates how the data elements from the bibliographic reference can be reflected in a source identifier, and how its constituent parts can be assembled to provide a unique identifier. This International Standard will facilitate the following: — identifying, tracing and validating terminological data and other language resources; — cross-referencing to documents containing terminological data; — data flow management in networking and other cooperative work in terminology documentation and terminography; — exchange of terminological data; — preparation of technical documents; — carrying out of individual projects of terminology and terminography. This International Standard does not take into account needs for a simpler approach that could be fulfilled by ISO 15836.

关键词： 实时   标识符   表结构   委托   宜昌   水文   水情数据库   雨水   水利部  

摘要： 受水利部国科司委托，部水文局于2004年9月9日至10日在湖北宜昌召开了(实时雨水情数据库表结构与标识符标准)审查会。

关键词： digital watermarking   biometrics   data security   authentication   user identification  

摘要： Two-dimensional (2D) barcode symbology is an emerging technology used for compactly storing and retrieving information. These barcodes can be found on the back of drivers' licenses and are encoded with secure text data. Standard 2D barcode such as PDF417 uses upper and lowercase alphabets, numeric digits and special characters for encoding. Some barcodes also include a compressed photo of the individual. The visual quality of the compressed image is usually poor and occupies a large amount of space which greatly reduces the capacity needed for encoding text. This paper presents a novel approach for embedding uncompressed images in a standard PDF417 2D barcode using a blind digital watermarking technique. The text is encoded in the standard PDF417 format with error correction, while the face and fingerprint images are watermarked in the encoded 2D barcode. Experimental results show that the proposed technique effectively increased the standard capacity of the PDF417 2D barcode without altering the contents of the encoded data. The results also show that the visual quality of the extracted photo image is high. The extracted fingerprint image when compared with the original fingerprint using an AFIS system yielded a high matching score. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： 低频   数据压缩   高频   量化   Huffman编码   传输   离散小波变换   标识符   门限   阀值  

摘要： 针对电力系统大量录波信号的传输问题,提出了一种压缩数据的实用方法。采用离散小波变换把数据从时域变换到频域,然后对高频系数取门限进行阀值量化,而低频系数则乘以一定倍数变成整型数据,最后把小波分解阶数,量化倍数,被保留的各级高频系数个数、大小和位置。原始数据个数,低频系数个数以及各数据之间的结束标识符一起进行静态Huffman编码。仿真分析表明,数据压缩比和重构误差都很小,证明该方法有效。