共查询到20条相似文献，搜索用时 671 毫秒
1.
对大数据的频繁项集挖掘是关联规则挖掘的关键步骤,通过有效的频繁项挖掘提高大数据量数据库的访问效率。传统方法中对大数据的频繁项集挖掘采用FP-Growth的粗糙集挖掘算法,扩展性和容错性不好。提出一种基于贝叶斯粗糙集的大数据频繁项挖掘技术,引入后缀项表的概念,通过后缀项表的构建,保留频繁项集的完整信息。构建FP-Tree,生成闭频繁项集,计算样本的密度,并抽取高密度区域的点集作为聚类中心集合,进行后缀项表的构造,按支持度分成若干集合,对各约简集内的属性集合进行融合,用变精度粗糙集的贝叶斯粗糙进行数据挖掘算法改进,仿真结果表明,算法不受可变参数的影响,鲁棒性较高,数据挖掘的准确度较高,运行时间较短。算法将在人工智能和数据挖掘领域具有更广的应用前景。 相似文献
2.
针对现代电力信息通信系统在出现故障的时候就会导致故障信息不确定或者不完整,或者还会导致丢失关键信息,以此无法对故障诊断进行正确推断的问题,就研究了基于粗糙集和贝叶斯网络的电力信息通信系统快速诊断方法。首先,将断路器、保护作为诊断属性,将故障区域作为决策属性,对其中的故障情况实现决策表的创建,之后根据信息熵属性及可辨识矩阵的方法将最佳的属性约简组合进行提取,最后通过最佳方式实现贝叶斯网络模型的创建,实现节点概率的训练。使用VB语言对方法故障诊断软件进行编写,通过结果可以看出来,此种方法有效且正确,能够提高系统在丢失核属性时候的容错性,并且具有良好的实用价值。 相似文献
3.
4.
《科技通报》2015,(10)
云计算环境下,需要对云数据特征进行深度融合,提高对云数据的调度和决策能力。传统的云数据融合算法采用置信增益概率分配算法,当云数据出现多重特征时,融合深度不够,信息提取效果不好。提出一种基于贝叶斯粗糙集的云数据深度融合算法。引入了置信增益函数贝叶斯粗糙集,得到贝叶斯粗糙集云数据模型构建,在特征空间关系中进行特征合并,进行决策表决策属性分区处理,提高融合精度,依据信任函数最大化原则确定新对象的决策属性取值,实现云数据深度融合算法改进。仿真实验表明,采用该算法,能有效提高数据融合深度和精度,稳健性较好,可以明显的抑制噪声的影响,并提高20 d B左右的特征空间增益,算法在高维空间中仍体现出了较为明显的数据融合优势,该算法在云计算和云数据信息处理等领域具有较好应用前景。 相似文献
5.
故障诊断是保障电力系统可靠运行的重要手段,本文对基于知识的电力系统故障诊断方法进行了综述,分析介绍了专家系统、人工神经网络、优化技术、petri网络、模糊集理论、多代理系统、粗糙集理论、贝叶斯网络等方法,最后对基于知识的电力系统故障诊断方法的发展趋势进行了展望。 相似文献
6.
7.
旅游景点信用评估是一种典型的分类问题,本文概述了粗糙集和决策树的理论,基于这两种理论,提出了一个基于数据挖掘粗糙集理论与决策树分类技术相结合的信用评估方法来建立旅行景点的信用评估模型,利用粗糙集的知识约简的概念,对样本数据进行预处理,去除冗余属性对分类模型的影响,然后用决策树方法建立分类模型。最后通过Pawlak重要度的属性约简算法和ID3决策树算法实现了该模型。 相似文献
8.
9.
为了能从通讯的角度识别犯罪团伙,文章以深圳杯夏令营数学建模的数据作为研究数据,利用贝叶斯网络分类器和粗糙集模型两种方法对识别出的结果进行验证。研究结果表示：通过贝叶斯网络分类器识别出的结果和粗糙集获得结果是一致的。从而可以给公安部分侦破犯罪团伙提供参考,提高犯罪案件的侦破率。 相似文献
10.
11.
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
12.
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
13.
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
14.
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
15.
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
16.
《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
17.
《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
18.
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
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
20.
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