共查询到20条相似文献，搜索用时 703 毫秒
1.
Web网络中存在海量文本,需要进行合理高效的文本抽取,实现Web文本数据挖掘。由于Web文本数据的高维特性,文本抽取过程中自动分类配对困难。提出一种基于RBF神经网络隐节点共振致密配对的Web数据文本抽取算法,进行Web数据文本特征采样与关联主特征挖掘,在每次移动中形成RBF隐节点共振致密配对,得到最优文本特征选择的路径,建立RBF神经网络分类器,实现基于蚁群算法的特征抽取算法改进。实验结果表明,该算法能有效实现对隐节点的共振致密配对,特征挖掘跟踪性能较好,保障了挖掘性能,系统所提取的特征分量与其他模糊分量差距较小,文本正确抽取召回率高于传统方法,在Web网络数据文本抽取中具有优越可靠的应用价值。 相似文献
2.
提出一种基于协方差特征爬虫的网页语义概念树构建方法,引入语义概念决策树算法进行主特征建模,根据语义三叉特征决策树概率正则训练迁移法则,得到决策树网络节点最近时刻获得的数据集有效特征概率,采用协方差特征网页爬虫进行网页语义概念树构建算法的改进。通过协方差特征爬虫,进行自相关成分的独立快速分离,得到语义自相关检索编码,实现网页语义概念树构建指导信息检索。仿真结果表明,该算法能有效进行数据挖掘和网页语义概念树的构建,为信息定位提供了最优分叉路径,从而实现对主题热点信息的准确检索和定位,算法具有较好的网页召回和定位检索性能,数据召回率提高明显,展示了较好的应用价值。 相似文献
3.
为了提高用户对网站使用的效率,提高网站本体模型的搜索性能,研究一种高效的网页语义概念树构建方法,进行搜索覆盖度层状拓展。传统方法中,使用搜索引擎的词语相似度算法进行搜索拓展,利用规则、聚类等技术对形式背景进行约简,无法有效简历概念间的上下位关系,性能不好。提出一种基于语义主题树特征匹配的搜索覆盖度层状拓展方法,进行Web语义模型和主题树构建,构建特征空间互信息区域文档词频向量模型,对数据库中记录的属性字段进行归类抽象,形成概念汇聚点,实现语义主题树构建搜索覆盖度拓展设计,构建语义主题树特征匹配算法,优化搜索引擎对文本特征的搜索敏感度,提高搜索覆盖度,实现文本搜索覆盖度层状拓展。实验分析得出,该方法具有较好的文本特征分类结果,语义层次结构清晰,可以有效提高文本数据召回率和查准率,展示了较好的应用价值。 相似文献
4.
对电磁脉冲信号相位特征的准确挖掘和参量估计可以有效准确地确定信号源的方位,实现对识别目标的准确定位。传统的相位特征挖掘算法采用贝叶斯估计算法,算法在受到脉冲干扰时估计性能不好。提出一种基于机器学习的电磁脉冲信号相位特征挖掘算法,实现对相位估计精度的改进提高。首先构建电磁脉冲信号的模型,得到相位特征挖掘模型原始模型,求解相位模糊数搜索结合解得到两个阵列输出数据的相位差。计算电磁脉冲信号参数相位补偿项,采用机器学习算法进行电磁脉冲信号相位特征挖掘,构建调频信号作为估计目标方位角的载波信号,采用最小二乘拟合求斜率最终实现相位特征等相关信息的挖掘。仿真实验表明,该算法能准确估计出电磁脉冲信号辐射源的相位等参数信息,相位特征挖掘性能较好,展示了优越的数据挖掘和目标检测定位性能。 相似文献
5.
《科技通报》2015,(8)
为了有效从海量的特征和噪声数据提取能表征目标特征的有用数据,提高对目标的检测识别能力,需要对目标回波特征的时频TID(time interference domain)域扩散参数进行快速挖掘,达到提取目标特征的目的。传统方法中采用频繁项挖掘方法实现扩散参数挖掘,导致在速度模糊的情况下对基带回波特征参数估计困难,性能不好。提出一种基于贝叶斯估计的目标特征识别扩散参数挖掘模型。有效挖掘出局部离群点,对基带回波特征进行频域变标脉冲压缩处理,对优化后的特征矢量进行累加限幅,并计算互补累积分布函数,基于贝叶斯估计构建检测统计量和统计函数,从而挖掘出时频TID域扩散参数,提高对特征参数的识别能力,仿真结果表明,该算法对时频TID域扩散参数挖掘精度较高,能有效提高对运动状态目标的参数估计精度及目标识别的能力。 相似文献
6.
随着大数据信息技术的发展,数据在线监测和数据挖掘成为计算机信息领域研究的热点。通过对Web热点数据分割挖掘,提高信息热点追踪和Web数据分类能力。传统算法采用非结构化数据挖掘算法,无法有效对Web热点数据进行准确定位和分层挖掘。提出一种基于半结构化分割的Web热点数据挖掘算法。采用半结构化数据进行特征分割,基于优秀基因位进行差分进化,使寻优曲线不断趋于平缓,在多个节点上并行的运行比较脚本,采用半结构化分割,使得Web热点特征挖掘实现自适应寻优,得到Web热点数据的分配因子,提高了挖掘性能。仿真结果表明,该算法获得了良好的效率和精度,提高了Web热点数据挖掘的自适应寻优能力。 相似文献
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8.
针对Web数据奇异特征挖掘时,信道对奇异特征具有卷积效应,影响特征挖掘精度。提出一种脉冲响应不变解卷积算法,实现对奇异特征对的盲解卷积,提高奇异特征挖掘性能。利用Web数据奇异特征的时间可预测性作为盲解卷积的解卷测度,采用脉冲响应不变算法对基于该测度的代价函数进行优化求解,从而成功得到解卷积滤波器系数,实现对Web数据奇异特征的盲解卷积。仿真实验表明,采用该算法挖掘Web数据的奇异特征,对于奇异特征信号具有很好的盲解卷积效果,所挖掘的奇异特征相关系数和重构信噪比均较高,特征挖掘聚类性好。 相似文献
9.
研究主要针对PageRank只考虑链接关系,而不考虑相关性的缺点进行了一些改进,把Web数据挖掘技术的内容挖掘应用到PageRank算法中,基于超链接文本和内容与主题的相关性,提出了PageRank算法的优化算法,并通过实验仿真,实验结果表明改进后的方法对提高更高相关性的网页的排名是有效的,符合人们的期望。 相似文献
10.
基于多因素方差分析的文本向量特征挖掘算法 总被引：2，自引：0，他引：2
文本向量特征挖掘应用于信息资源组织和管理领域,在大数据挖掘领域具有较大应用价值,传统算法精度不好。提出一种基于多因素方差分析的文本向量特征挖掘算法。使用多因素方差分析方法得到多种语料库的特征挖掘规律,结合蚁群算法,根据蚁群适应度概率正则训练迁移法则,得到种群进化最近时刻获得的数据集有效特征概率最大值,基于最优划分的K-means初始聚类中心选取算法,先对数据样本进行划分,然后根据样本分布特点来确定初始聚类中心,提高文本特征挖掘性能。仿真结果表明,该算法提高了文本向量特征的聚类效果,进而提高了特征挖掘性能,具有较高的数据特征召回率和检测率,时间耗时较少,在数据挖掘等领域应用价值较大。 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