共查询到20条相似文献，搜索用时 138 毫秒
1.
《科技通报》2015,(8)
通过对智能数据库的特征优化挖掘,实现特征数据融合,优化数据库分组访问信道,提高数据调度效率。当前的智能数据库特征挖掘算法采用相关度匹配的特征级联挖掘技术,当分层特征之间的具有较大的相似度时,挖掘效果不好。提出一种基于小波多窗谱提取的智能数据库特征挖掘算法。构建数据库模型,建立GMS方法以最小的代价和以最小的样本偏差来实现最高质量的样本数据集,采用粗糙概念格的生成算法进行数据流的频繁访问特征分区,构建小波函数,得到智能数据库的特征双曲调频母小波,提取数据库信息流的多窗谱特征,进行智能数据库特征挖掘算法改进。仿真结果表明,该算法进行数据库特征挖掘的运行时间较短,数据库特征挖掘精确度较高,提高了对数据库的访问和数据调度的精度和效率。 相似文献
2.
《科技通报》2015,(8)
在数字化信息系统中,将大量网络计算资源、存储资源与软件资源等多源信息资源进行多层次异构存储,对信息资源的调度和检索成为难题。传统的多源信息检索方法采用概念格差异融合算法,无法有效识别差异化网络数据的语义特征,检索性能不好。提出一种基于概念格特征分区的多源信息检索优化算法。概念格的生成是进行数据分析、关联分析和挖掘关联规则的前提,首先给出概念格的构造模型,进行概念格特征分区,得到数据库集合的特征概率函数密度,构建满足约束条件的无冗余概念格,计算多源信息的两种相似度系数,挖掘约束关联规则,提高信息检索精度。仿真实验表明,该算法实现多源信息检索性能优越,无偏性好,精度较高。 相似文献
3.
研究GPS全球定位系统大数据库的分区方位特征分割问题,提高GPS大数据访问的抗干扰能力。传统方法采用基于块匹配的GPS大数据定位信号调度方法实现数据访问,在弱信号强干扰环境下干扰抑制能力差,算法稳健性不好。为解决这一问题,提出一种基于模式匹配的GPS大数据库分区访问特征分割算法,构建GPS大数据库数据访问模型,数据块按可靠性需求划分为若干个等级,得到储节点模块匹配模型,设计GPS大数据信息流集合划分机制,对流量信息占用概率进行特征匹配,实现GPS大数据库分区访问特征分割,通过计算数据访问的精确度和抗干扰能力等指标进行性能测试分析,仿真结果表明,采用该算法能较好地反映GPS大数据信息流的分区特征,特征分割效果较好,数据访问中抗干扰能力强,实时性好,GPS大数据定位信息访问精度较高,具有优越性。 相似文献
4.
5.
6.
Bordat建格算法是一种有效的基于形式背景建造概念格的算法,在Bordat算法中,需要频繁地扫描数据库,并且在子节点生成时,重复生成了许多重复的节点。本文对概念格建格算法Bordat进行深入分析,对该算法进行改进。新的算法只需一次扫描数据库就能够生成概念格,并有效地克服了Bordat算法中重复节点重复产生的问题。 相似文献
7.
针对级联数据库中可逆隐藏数据定位不准,访问恢复困难的问题,提出一种基于非对称补偿粒子滤波的可逆隐藏数据访问算法,实现对数据库中可逆隐藏数据准确访问。算法使用非对称粒子滤波对数据库中可逆隐藏数据的目标位置和访问信道衰减参数进行同时估计,提高可逆隐藏数据定位精度。设计非对称补偿滤波器,抑制数据访问中相干数据干扰,采用迭代方式对隐藏数据访问进程进行更新。最后采用取对数能量求倒谱的方法对数据进行恢复处理,实现对可逆隐藏数据的精准定位访问。仿真实验表明,采用该算法对大型级联数据库进行访问,能准确定位可逆隐藏数据,抗干扰能力强,无损可逆性好,数据库访问识别率和鲁棒性均有明显提高。 相似文献
8.
9.
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
10.
传统方法以不同数据库数据紧密逻辑特征和均值特征进行失效数据的定位,没有考虑逻辑特征被破坏带来的定位误差过大问题。提出基于困难区域划分思维的级联数据库查询方法。算法引入困难区域的概念,在设置初始簇中心时,以数据融合属性特征为基础,对属性融合差异较大的区域进行划分,形成融合困难区域,在困难区域内,计算最大的属性困难度的相似性,并对上述特征进行聚类分析,完成数据属性特征的筛选,优化查询过程。实验结果表明,利用该算法进行差异级联数据库的数据库查询,能够删除数据库中的冗余数据,提高数据库的查询效率。 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.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
15.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
16.
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
17.
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
18.
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
19.
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
20.
《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献