共查询到20条相似文献，搜索用时 62 毫秒
1.
K-means算法是一种应用广泛的聚类算法,但是存在初始聚类中心和K值选取的难题.本文提出了一种基于学术文献同被引分析的初始聚类中心和K值选取的K-means改进算法.该算法属于两步聚类算法,首先对学术文献进行同被引分析,得到同被引矩阵,然后基于同被引矩阵进行层次聚类.算法记录每次迭代过程中被聚为一类的学术文献间的距离以及两次迭代间的距离差,当两次迭代的距离差取得最大值时取其聚类数作为第二步K-means算法的K值,并且将此时的类中心作为第二步K-means算法的初始聚类中心.第二步聚类则依据文献内容实现K-means算法.实验通过与经典K-means算法和基于凝聚层次聚类算法的改进K-means算法的对比,证明了本文提出的改进的K-means算法具备更优的聚类效果. 相似文献
2.
K-means算法研究综述 总被引：4，自引：0，他引：4
对聚类分析中的基本算法K-means算法中的K值确定、初始聚类中心选择以及分类属性数据处理等主要问题进行综述,理清K-means算法的整个发展脉络及算法研究中的热点和难点,提出改进K-means聚类算法的思路。 相似文献
3.
一种基于改进K-means的文档聚类算法的实现研究 总被引：1，自引：1，他引：0
在对文档聚类的含义、作用和一般过程的阐述基础上,分析一种基于“最小最大”原则初始质心优选的改进K-means聚类的基本思想,并重点设计相关的聚类算法,实现聚类系统,基于系统对300篇学术文档及其相关特征词语进行聚类实验。实验结果表明,本文所设计和实现的改进K-means的聚类算法表现出较好的性能。 相似文献
4.
提出利用蚁群聚类方法进行初始聚类,通过K-means聚类算法对初始聚类的结果进一步分层聚类,并结合术语综合相似度计算的方式提取每个类的标签,从而完成术语层次关系的构建。最后抽取部分实验结果,由领域专家对其进行评价,并对结果进行分析。 相似文献
5.
文章在对DBSCN与K-means两种经典聚类算法分析研究基础上,结合中文文本数据的特点,对这两种方法进行结合与改进,提出了一种中文文本聚类方法：DKTC。该算法能自动产生簇的个数,且对“噪声”或异常数据不敏感,对数据的输入顺序不敏感,另外,与DBSCAN相比,该算法有更高的处理效率。实验表明,DKTC算法不仅能对中文文本进行聚类,且与传统DBSCN与K-means法相比,聚类效果都有一定程度的改善。 相似文献
6.
7.
提出了一个新的基于双向近邻技术的多层文档聚类算法。使用新的文档特征抽取方法构造了文档的主题和关键字特征向量。首先在主题特征向量空间中,改进了传统的最近邻技术,使最近邻概念由单向变为双向。利用改进后的方法对文档进行初始聚类,然后在基于主题关键字的新的特征向量空间中利用类间距和连接度对初始文档类进行求精,从而得到最终聚类。由于使用了两层聚类方法,使算法的效率和精度都大大提高。最后对算法的有效性、可伸缩性和时间复杂度进行了研究。 相似文献
8.
基于粒子群的模糊C均值文本聚类算法研究 总被引：1，自引：0，他引：1
9.
基于粗糙用户聚类的协同过滤推荐模型 总被引：1，自引：0，他引：1
【目的】将粗糙集引入到基于用户聚类的协同过滤中,提高推荐质量。【方法】提出一种基于粗糙用户聚类的协同过滤推荐模型:离线时采用粗糙K-means用户聚类算法,根据用户与聚类中心的相似度将其分配到K个类的上、下近似中,形成用户的初始近邻集;在线时从目标用户的初始近邻集中搜索其最近邻,预测项目评分并向其产生推荐。【结果】通过实验对比发现,该模型比传统的和基于项目的协同过滤推荐算法降低约14%的平均绝对误差,比基于用户聚类的协同过滤推荐算法降低约10%的平均误差。【局限】在考虑上、下近似对聚类中心调整的重要程度时,忽略了用户聚类数目和最近邻集用户数阈值的变化所产生的影响。【结论】该模型能有效提高推荐精度,具有较强的可行性和现实意义。 相似文献
10.
11.
《Slavic & East European Information Resources》2013,14(1-2):123-143
ABSTRACT The article examines the most important periodicals of ethnic minorities in Poland. After 1989, many ethnic groups (e.g., Germans and Romanies) were allowed to publish journals and newspapers for the first time since the end of World War II. The publications examined show the rich cultural life of the various ethnic groups as well as their current status in Poland. In addition to popular titles, some scholarly publications are also discussed. 相似文献
12.
Josie Barnes Parker 《图书馆管理杂志》2013,53(6):731-737
ABSTRACTIn today's current political environment raising support for millage renewals, bond campaigns or even millage continuations for public libraries is affected by national politics, and a tendency towards tax aversion on principle across the country. The lessons we can learn from the governing boards of small and rural public libraries are worth raising up to a greater national consciousness. Board governance, community consciousness, and facilities management are clear and logical tools that elected boards of public libraries can use to politick for support of libraries. 相似文献
13.
Jon C. Giullian 《Slavic & East European Information Resources》2013,14(3):278-284
The author answers a reference question on bibliographic sources for the Ukrainian periodical press 1840–1850. Helpful publications include bibliographies, guides, and library catalogs. These potentially make mention of revolutionary developments in Hungary (such as the Twelve Points paragraph of the Demands of the Hungarian Nation in March 1848, the subsequent April Laws, and Hungary's declaration of independence in April 1949), and elsewhere in the Hapsburg Empire. 相似文献
14.
《Slavic & East European Information Resources》2013,14(1):25-74
ABSTRACT The history of the almanac in Croatia is reconstructed through primary research in bibliographic and archival sources. The almanac is a vehicle for knowledge communication in informal contexts, engaging both oral tradition and literary forms traceable to medieval literacy and ways of structuring knowledge. The history of the almanac in Croatia reflects the changing context of the book trade, literacy, and the evolution of language. Four main stages are identified: (1) the beginning of the annual almanac in the seventeenth century; astrological almanacs reflecting the sensibility of the Baroque period; (2) the Enlightenment's stimulation of almanac publishing in the spirit of contemporary secular reforms in agriculture and education; (3) nineteenth-and twentieth-century almanac trade, showing complex and overlapping networks for the production, distribution and appropriation of printed almanacs;(4) roughly the end of World War II, when the almanac slowly moved out of the role of a popular mass medium and into specialized niches represented by regional, diaspora, and religious almanacs. 相似文献
15.
Neil De Young 《Publishing Research Quarterly》2009,25(3):139-146
Some key questions for publishers in today’s market are: Could Amazon’s recent merger and acquisitions strategy create a disruptive or paradigm shifting business model in the publishing industry? Do their recent actions post mergers and acquisitions illustrate a predicable pattern of behaviour that publishers can strategize around? This paper will explore these questions and look at some of the possible reasons behind Amazon’s business practices and the possible consequences to publishers. 相似文献
16.
Barbara Lison 《图书馆管理杂志》2013,53(2):180-187
ABSTRACTGerman authorities are expecting more than 1 million refugees by the end of 2015. These people come to Germany to seek protection and assistance and to build a new life, therefore it is important to welcome them and to assist them in their integration as soon as possible. This situation creates a versatile and perfectly fitting opportunity for cultural and educational programs, including libraries, which can play a vital role in this integration process. The key to integration is the knowledge of the German language, and the most important challenge now is to teach the necessary language skills to as many asylum-seekers as possible. 相似文献
17.
《Journal of Web Librarianship》2013,7(1):41-59
Abstract Many libraries use RSS to syndicate information about their collections to users. A survey of 65 academic libraries revealed their most common use for RSS is to disseminate information about library holdings, such as lists of new acquisitions. Even though typical RSS feeds are ill suited to the task of carrying rich bibliographic metadata, great potential exists for developing applications that can exploit metadata exposed to Web services via RSS. Using the MODS metadata format, entire catalog records can be seamlessly embedded in RSS 2.0 feeds. Existing tools, such as Library of Congress Java toolkits and XSLT stylesheets, can facilitate this process, while a new XSLT stylesheet may be used to create the RSS feeds complete with MODS records. As an example of the added functionality these MODS/RSS feeds can offer, records from a MODS-enriched RSS feed can be ingested into a non-RSS application such as Zotero. As more emerging library technologies use Web services architectures to handle data objects, the ability to syndicate catalog records will become more critical to providing innovative library Web services. 相似文献
18.
Michelle Rodino-Colocino 《Critical Studies in Media Communication》2013,30(5):375-390
This essay investigates key moments in the history of personal digital assistant (PDA) marketing to women. Analyzing promotional texts for three PDAs that received considerable press coverage from 1999 to 2001, this essay explores the cultural significance of the convergence of anxieties about women's place in the gendered division of labor with the computer industry's changing marketing imperatives. Drawing on an array of promotional texts, including news articles, press releases, promotional Web sites, and ads appearing in newspapers and magazines, this paper tells the story of how the computer industry aimed to sell smaller, faster computing devices to women while promising to mediate and thus reproduce women's overwork as paid and familial laborers. After experimenting with the PDA as a sexy fashionable gadget for working women, marketers approached women as mothers with “Audrey,” an Internet appliance designed for the kitchen. 相似文献
19.
Lindsay Dillingham 《Journal of Business & Finance Librarianship》2013,18(4):313-327
This study explores the attitudes and actions of bank managers toward communication spending during recession. Results of this study indicate that organizational leaders cut communication spending early during recession and also erroneously rely on the bank's financials to mitigate irrational customer withdrawals. This research is used to illustrate the need for public librarians to meet the needs of bank stakeholders when their institution ceases to communicate during crises, for academic librarians to educate students in undergraduate and graduate programs regarding heightened information needs during recession, and for corporate librarians to understand a potential avenue for competitive advantage during recession. 相似文献
20.
指出共链分析已在商务网站评价、竞争情报分析、商业信息挖掘等领域有广泛应用。综合运用共链分析与社会网络分析的方法,对国内市场份额排名前50位的电子商务网站的企业竞争态势与竞争关系及地位进行综合分析,并对企业间潜在竞争关系挖掘进行初步探索,以期能对竞争情报方法论研究和国内电子商务市场的发展提供一定的启示和参考。研究发现,共链网络中节点的程度中心性与企业实际的市场份额之间存在显著的相关关系,且竞争关系多存在于不同组织下业务类型相似的企业实体,而有些互补服务的企业之间则是合作关系的存在,这一发现或许能为未来电子商务市场发展战略规划与制定提供一定的指导和帮助。 相似文献