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1.
《科技通报》2015,(8)
混合云存储系统的大数据部署和管理过程中,出现大量冗余数据,需要对冗余数据合理删除,获取想要云端的数据,提高系统稳定性。传统的冗余数据删除算法会在分数阶Fourier域出现伪峰峰值,不能有效地对冗余数据进行检测滤波和删除处理,提出一种基于压缩特征码的混合云冗余数据删除算法。预测出不同时间片内混合云的任务执行期望完成时间,对混合云数据冗余主成分进行特征编码,表征为校验信息存储子集对部分冗余数据的块层结构,提高冗余数据删除性能,实现算法改进。仿真结果得出,该算法对云存储系统中冗余数据的检测性能较好,有效避免数据信息流的干扰特征造成的误删和漏删,冗余数据删除准确性高,具有较好的应用价值。 相似文献
2.
在云存储服务中,为使用户可以随时验证存储在云存储服务器上数据的完整性,需要对云计算数据进行移动学习,在移动学习过程中,产生大量的重复数据。需要设计云计算静态重删系统,对重复数据有效及时删除。传统方法采用虚拟化云平台分类层次重删模型,需要修改内核代码或者以模块的形式动态植入内核代码,重删效果不好。本文提出一种基于奇异值分解移动学习的云计算静态重删系统设计方案,进行云计算存储系统设计与重删数据特征分析,对云计算静态重复数据的尺度伸缩分解,把重复数据宽带互模糊度函数映射为一个检测统计量特征分解问题,构建一个参数未知多重假设检验,对云计算静态重复数据进行奇异值尺度伸缩分解,对分解后的奇异值特征进行状态空间重组和移动学习,得到重删系统模型改进。仿真结果表明,该算法对云计算静态重复数据检测性能较高,重删性能优越,抗干扰能力强,具有较好的应用前景。 相似文献
3.
基于块奇异值分解的水印算法研究 总被引：8，自引：0，他引：8
奇异值分解是一种特殊的矩阵变换，并具有良好的性质。本文充分利用奇异值分解的特性，提出了一种新的基于块奇异值分解的量化水印算法和一种新的基于块奇异值分解的扩频水印算法。这两个算法都是通过对各个数据块的最大奇异值进行修改来嵌入水印，都可以根据待嵌入的水印信息量来调整分块的大小，算法的复杂度较低。其中的量化水印算法是含边信息的嵌入方法，可以实现盲检测。实验结果证明，基于块奇异值分解的水印算法对常规的图像处理攻击具有很好的鲁棒性，尤其是其中的量化水印算法。 相似文献
4.
伴随网络技术迅速发展与广泛应用,云计算逐渐成为对海量数据计算主要运算形式。由于数据通过高维形式储存,造成严重存储开销。文中以海量激光雷达数据为研究对象,在云计算下对存储系统进行优化设计。对于海量激光雷达数据,采用New-blocking分块策略,设定分块阈值包括最小分块因子值和最大分块因子值,利用阈值判定是否对文件分块,通过定义文件均匀度获得文件分块大小数据值;运用增加副本策略,根据文件热度判断其被访问情况,增加此文件block副本缓解负载。为进一步解决负载问题,运用数据动态平衡模型对激光数据进行监控、合并、拆分及数据移动等步骤处理,使物理节点通过迁移虚拟节点完成资源重分配,从而实现数据动态存储系统优化设计过程。实验证明,该系统能够有效存储激光雷达数据并达到系统资源使用率最大化的目的。 相似文献
5.
根据当前教育信息化的需求和挑战,本文通过实际数据测试提出了一个云存储系统在教育信息化中的应用方案.在原型验证系统中,采用HepyCloud海量云存储系统.该存储系统既具有分布式存储扩展性好、可用性高的优点,又有客户端访问速度快、性能较稳定等特点,适用于教育信息化建设中音、影、图及管理信息等大容量、高访问的应用系统.通过实际测试教育信息化系统中最常应用的网站中小文件访问和FTP大文件应用访问两个案例进行实际应用性能测试,测试结果表明该云存储结构方案能够解决传统教育信息化系统中的文件存储效率不高的问题,提高了数据存储效率和数据被访问的性能,很好地支持了用户对各种类型数据的访问. 相似文献
6.
采用改进的隐式曲面重建模型,采用分层次重建思想和局部支撑的径向基函数相结合的重建算法,使其结合了局部和全局函数的优点,采用局部支撑径向基函数有效降低系统求解复杂度,分层方法可以有效处理残缺和非均匀点云数据。算法首先对点云数据进行层次划分,接着递归地将前一级的插值结果作为后一级的偏移,由粗糙到精细逐步改善重建结果。实验结果表明,算法简单易实施,重建效果良好。 相似文献
7.
激光扫描点云数据存储是目前地理信息系统和测量系统的一个重要研究方向,点云数据存储系统的效率影响着点云数据处理分析能力,从而影响地理信息的获得,以及对测量等方面工作造成影响。传统的激光扫描点云数据库存储系统,一直存在存储内存空间大,存储效率却很低的问题。提出基于OTSU多阈值分割的激光扫描点云数据存储系统设计方法,首先分析点云数据查询系统结构,了解用户需求,完成系统运行平台的选择及系统安全性的分析,从而完成点云数据存储和管理框图,然后利用OTSU多阈值分割方法对数据库数据进行分析,提高激光扫描点云数据存储系统查询结果的准确性,通过仿真实验证明,所提方法能够有效提高激光扫描点云数据存储系统效率且占用的内存较其他方法小,具有较高的实用价值。 相似文献
8.
对大型云动态数据的完整性检测可以避免云用户存储在其中数据被篡改或删除。传统方法中,采用代数结构标签加密方法进行数据完整性检测,不能保证足够的置信度,性能不好。在云储存环境下,提出一种基于可信第三方判定和动态标签信息更新的多路复用大型云动态数据完整性检测方法。假设被处理云采集数据的是可分类的,引入了一个管理因子,得到多路复用标签信息,基于可信第三方判定和动态标签信息更新进行,进行对用户存在云存储服务器上的文件块被篡改或删掉的判定,由此实现一次数据完整性验证,提高大型云动态数据检测的准确性。仿真结果表明,该算法具有较好的多路复用大型云动态数据完整性检测性能,系统使用率提高,计算开销较少,检测准确性提高。 相似文献
9.
本文针对数字水印的抗攻击性问题,提出了一种新的基于置乱和奇异值分解的算法.算法首先将水印和载体图像同时进行置乱加密,再将置乱后的图像进行分块,然后对每块进行量化奇异值分解,在特征域嵌入水印.将双置乱技术引入分块量化奇异值分解方法中,进一步提高了奇异值分解算法的鲁棒性.其中,采用分块和置化特征矩阵的方法不用计算整个图像的SVD,大大缩短了水印嵌入和提取的时间. 相似文献
10.
在CStor云数据库访问中,细粒度云存储数据的信息特征存在个体较大差异,访问路径产生多频偏移,数据访问调度性能受限。传统方法中采用PSO局部搜索方法进行访问路径修正,搜索效率低,个体更新较慢。提出一种基于细粒度云存储数据迭代恢复匹配的云数据库访问路径偏移修正算法,以PSO多信息融合Pareto支配集为指导,构建多信息融合细粒度数据的主特征模型,采用迭代恢复匹配方法增加了局部搜索提高搜索到全局最优解的几率,实现路径偏移修正。仿真实验采用3组测试集对CStor云数据库进行访问调度和路径偏移修正,结果表明采用该算法,实现对访问路径的动态实时修正,收敛距离较小,提高了CStor云数据库访问和数据挖掘性能。 相似文献
11.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
13.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
14.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
15.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
16.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
17.
Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
18.
Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
19.
Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
20.
Leah A. Lievrouw 《The Information Society》1998,14(2):83-96
The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests. 相似文献