课程文献中心 更多>>

关键词： 对等网络   分布式哈希表   主成分分析   邻近标识符选择  

摘要： 保持对等网络与底层网络的拓扑良好契合是保障对等网络性能的重要条件.以对等网络系统CAN为基础,将底层网络拓扑建模为高维欧氏空间,使用主成分分析法将底层网络拓扑映射到低维CAN逻辑空间,从而根据节点在底层网络中的位置决定其在对等网络中的标识符.实验结果表明,该算法能够有效减少对等网络链路延时,提高路由效率.

关键词： ISSN   linking ISSN   ISSN-L   ISO 3297   serials   continuing resources   identifiers  

摘要： This article is an updated version of an article based on a NASIG 2005 presentation that explored the background and progress of the revision of the ISSN standard. The ISSN standard, ISO 3297, has been in existence for over 30 years. ISO standards are reviewed every five years for relevance and to determine if they need updating. For most of its lifetime (with a few exceptions when more significant revisions have occurred), ISO 3297 has been approved without substantial revision. However, the 2003 ISO review resulted in the decision to revise the standard to better meet the needs of the digital environment. A Working Group was formed in late 2003 to revise the standard and, in ISO voting completed November 6, 2006, the revised standard was approved unanimously. Although the assignment of separate ISSN to each medium version of a continuing resource is confirmed in the revised standard, a new mechanism is described, called the linking ISSN (ISSN-L), which is intended to enable the use of ISSN in cases where finding or linking to a continuing resource without regard to medium is desired. Publication of the revised standard is slated for April 2007. [PUBLICATION ABSTRACT]

关键词： Boolean Galerkin discretization   Fredholm integral equation   multidimension   two-scale  

摘要： In this paper, some two-scale Boolean Galerkin discretizations are proposed and analyzed for a class of Fredholm integral equations of the second kind in multidimensions. It is shown by both theory and numerics that this type of multiscale discretization algorithm not only significantly reduces the number of degrees of freedom but also produces very accurate approximations.

关键词： internet of things   coding schemes   communication protocols   decentralized systems  

摘要： Managing product information for product items during their whole lifetime is challenging, especially during their usage and end-of-life phases. The main difficulty is to maintain a communication link between the product item and its associated information as the product item moves over organizational borders and between different users. As network access will typically not be continuous during the whole product-item lifecycle, it is necessary to embed at least a globally unique product identifier ( GUPI) that makes it possible to identify the product item anytime during its lifecycle. A GUPI also has to provide a linking mechanism to product information that may be stored in backend systems of different organizations. GUPIs are thereby a cornerstone for enabling the Internet of Things, where 'intelligent' products' can communicate over the Internet. In the current paper, we analyse and compare the three main currently known approaches for achieving such functionality, i.e. the EPC Network, DIALOG and WWAI.

关键词： optimal clones   bioinformatics tool   comparative genomic hybridization   gene expression   DNA microarray   genomic shotgun libraries  

摘要： In DNA microarray experiments, the gene fragments that are spotted on the slides are usually obtained by the synthesis of specific oligonucleotides that are able to amplify genes through PCR. Shotgun library sequences are an alternative to synthesis of primers for the study of each gene in the genome. The possibility of putting thousands of gene sequences into a single slide allows the use of shotgun clones in order to proceed with microarray analysis without a completely sequenced genome. We developed an OC Identifier tool (optimal clone identifier for genomic shotgun libraries) for the identification of unique genes in shotgun libraries based on a partially sequenced genome;this allows simultaneous use of clones in projects such as transcriptome and phylogeny studies, using comparative genomic hybridization and genome assembly. The OC Identifier tool allows comparative genome analysis, biological databases, query language in relational databases, and provides bioinformatics tools to identify clones that contain unique genes as alternatives to primer synthesis. The OC Identifier allows analysis of clones during the sequencing phase, making it possible to select genes of interest for construction of a DNA microarray.

关键词： 数字期刊   唯一标识符  

摘要： 通过对DOI标准规范的描述，对比国内外几大数字文献生产商DOI标识规范和DOI解析系统的建设情况，从信息资源建设角度论述了中文DOI标识规范和DOI解析系统建设的意义。

关键词： 多链路   标识符   分片   重组   缓存器   帧格式  

摘要： 多链路ppp可以快速的传输数据,在传输中数据被分片重组,数据包自带寻址地址,而且是通过实际上的多条物理链路来传输。从而解决数据传输中速率和带宽的问题,也可以降低网络传输的成本。

关键词： generalized estimating equations   longitudinal data   maximal correlation   type I error  

摘要： Longitudinal population-based surveys are widely used in the health sciences to study patterns of change over time. In many of these data sets unique patient identifiers are not publicly available, making it impossible to link the repeated measures from the same individual directly. This poses a statistical challenge for making inferences about time trends because repeated measures from the same individual are likely to be positively correlated, i.e., although the time trend that is estimated under the naive assumption of independence is unbiased, an unbiased estimate of the variance cannot be obtained without knowledge of the subject identifiers linking repeated measures over time. We propose a simple method for obtaining a conservative estimate of variability for making inferences about trends in proportions over time, ensuring that the type I error is no greater than the specified level. The method proposed is illustrated by using longitudinal data on diabetes hospitalization proportions in South Carolina.

关键词： 高宽比   彩色印刷   数据交换   数据格式   数据输出   数字数据   印刷业   成象   信息交流   印刷   标识符  

标准号: ISO 12639 AMD 1-2007

摘要： This standard is Graphic technology - Prepress digital data exchange - Tag image file format for image technology (TIFF/IT); Amendment 1: Use of JBIG2-Amd2 compression in TIFF/IT

关键词： 面向方面编程   方面挖掘   标识符分析   形式概念分析   预过滤器  

摘要： 面向方面编程技术与传统的重构技术融合，掀起了面向方面软件重构研究的热潮。这一课题分为方面挖掘和方面重构两个步骤，方面挖掘是方面重构的先决条件，也是面向方面软件重构的关键步骤，其结果直接影响软件重构的进行。 本文选取一种典型的方面挖掘方法——标识符分析方法，将研究重点放在对方法的改进和提高上。标识符分析方法面临着概念生成时间爆炸、手工挑选概念复杂难行以及在大型遗产系统中难于应用三大难题，其原因在于标识符分析使用形式概念分析算法生成大量形式概念，时间消耗大，并且结果包含了大量干扰挖掘的冗余概念。通过分析，作者发现，能够通过对生成概念格的上下文表进行预过滤，阻止那些对有效概念的生成毫无用处的元素和属性进入概念生成阶段。据此，作者给出了一系列定义、命题及其证明，保证所用的过滤方法有正确的理论依据，并在此理论基础上，提出了名为“预过滤器”的预过滤算法，将上下文表转化成上下文矩阵，通过对矩阵进行简单、巧妙的数学变换和运算，高效、灵活地实现对上下文的过滤。值得说明的是，预过滤算法的应用范围不局限于方面挖掘方法，只要对感兴趣的概念包含的元素和属性个数有要求，就可以考虑使用，因此具有一定的普遍意义。 改进的标识符分析方法，将预过滤器加入到概念生成步骤之前，有效地控制了概念生成的输入量，节省了大量概念生成时间，减少了冗余概念的生成，生成的概念格结构更加清晰，向“所得即所需”的理想状态迈进了一大步;并且降低了手工挑选横切概念的工作量和复杂度，提高了标识符分析方法的挖掘能力和适应性。