共查询到20条相似文献，搜索用时 933 毫秒
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基于共词分析法的学科主题演化研究方法的构建 总被引：1，自引：0，他引：1
[目的/意义]相比于以单纯的关键词统计排序为主的词频分析法,和以文献作为分析对象、需要庞大的引文索引作为基础的共引分析法,共词分析法具有一定的优势。因此,基于共词分析法来研究学科主题演化规律。[方法/过程]构建基于共词分析法的学科主题演化研究方法,包括4个模块,分别是：数据准备、演化阶段划分、主题识别和主题演化分析。[结果/结论]在主题识别阶段改进了词频g指数来选取共词分析的对象;在主题演化分析模块,提出从静态和动态两个角度来分析学科主题的演化情况,构建三维战略坐标来进行静态分析,并构建学科主题演化现象识别模型来进行动态分析。 相似文献
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复杂网络领域科研合著网络演化及知识传播特点研究 总被引：1，自引：0，他引：1
以复杂网络研究领域1975年-2012年间的科研合著网络为例,分4个发展阶段对科研合著网络的静态特征、拓扑特征、动态演化特征等参数进行计算,来解释和说明科研合著网络的演化和知识传播特点。仿真实验表明:当知识传递率一定时,知识传播速度受到个体创新能力的影响较大;当个体创新能力一定时,知识传播速度受到知识传递率的影响较小。 相似文献
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[目的/意义]旨在研究肿瘤疫苗领域技术创新合作网络演化特征,为我国肿瘤疫苗领域的技术突破和产业发展提供思路。[方法/过程]提出一种产业技术创新合作网络演化特征分析方法和框架。首先引入专利指标法,通过技术生长率、技术成熟系数、技术衰老系数和新技术特征系数等指数的定量计算对肿瘤疫苗产业技术生命周期进行划分;其次利用社会网络分析法构建技术生命周期各阶段合作网络,从节点数、网络密度、中心势、核心-边缘分析等维度对合作网络的拓扑结构演化规律进行分析;从中心度、凝聚子群分析、创新机构等维度对核心个体演化规律进行分析,进而揭示肿瘤疫苗产业技术创新合作网络的动态演化特征。[结果/结论]以肿瘤疫苗战略性新兴产业为案例进行研究,验证方法的有效性和可行性,为肿瘤疫苗领域技术发展战略和技术合作提供理论依据。 相似文献
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[目的/意义]对知识网络中结构关系的有效识别与提取，有助于从纷繁的数据中探测知识网络的拓扑结构及其演化模式。[方法/过程]本文提出一种基于邻接矩阵特征分解的知识网络结构关系提取方法。基于真实数据分别从静态结构关系提取和动态结构演化两个方面，对特征分解法和传统关联频度法进行对比分析，并与Pathfinder算法进行对比。对基于特征分解法提取知识网络结构关系的有效性进行验证。[结果/结论]研究结果表明：特征分解法能够识别原始知识网络中的主要成分信息，能够准确识别低频次的对网络整体拓扑结构较为重要的关联关系，且提取方法灵活自由。 相似文献
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复杂网络视角下网络信息生态链的演化过程研究 总被引：1，自引：0，他引：1
[目的/意义] 利用复杂网络理论分析网络信息生态链演化过程,以期推动网络信息生态链由无序、低效、不稳定的状态向有序、高效、稳定的状态演变,为网络信息生态链的模拟仿真和实证分析提供参考。[方法/过程] 根据复杂网络理论,在分析信息节点的传播特征和结构变化后,提出网络信息生态链动态演化模型,以此推算出演化速度方程和速度曲线;利用Logistic方程的生命周期曲线,描绘出网络信息生态链演化过程曲线。[结果/结论] 根据曲线的演化速度与加速度的不断变化,发现网络信息生态链的演化过程主要分为4个阶段,即萌芽期、成长期、稳定期以及退化期,最终形成“聚类-协同-循环”的有效模式,帮助网络信息生态链建立起科学、高效的发展机制。 相似文献
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[目的/意义]虽然已有学者通过实证分析社会化问答用户信息搜寻的影响因素,但是目前研究还未探究影响因素间的搭配组合对信息搜寻的影响。为解决这一研究局限,从混合方法的视角出发,在回归分析方法的基础上借助定性比较分析法（qualitative comparative analysis,QCA）来深化对用户特征因素和激励因素之间搭配组合产生影响的认识。[方法/过程]通过回顾先前关于网络用户信息搜寻行为影响因素的研究,指出可以采用QCA来尝试解决存在的研究局限,并以社会化问答用户信息搜寻为实例,运用回归分析方法和QCA方法分析社会化问答社区用户信息搜寻行为的影响因素,比较和总结这两种方法得到的结果。[结果/结论]研究表明,回归分析有助于研究者发现哪些因素会对网络用户的信息搜寻行为产生显著影响,而QCA方法有助于研究者发现这些影响因素如何组合搭配来产生影响作用。 相似文献
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融合主题与情感特征的突发事件微博舆情演化分析 总被引：1，自引：0，他引：1
[目的/意义]微博是突发事件网络舆情传播的重要媒介。面向突发事件的微博主题和情感挖掘对掌握突发事件的网络舆情、识别与预测潜在问题及风险等方面具有重要的实践意义。尝试提出一种融合主题与情感特征的突发事件微博舆情演化分析方法。[方法/过程]以寨卡事件为例,通过划分微博舆情演化的生命周期,基于word2vec技术分别提取该事件生命周期各阶段的微博主题,采用基于词典的情感分析方法,引入情感词、表情符号等多情绪源,对不同主题下的评论情感做细粒度划分,并计算情感强度,最终实现微博主题与情感的协同分析。[结果/结论]所提出的微博舆情演化分析方法能够揭示面向特定事件的微博在突发事件生命周期各阶段的主题特征、情感类型与强度,剖析网络舆情主题与情感特征的协同演化规律。 相似文献
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一种基于ART-2神经网络的案例检索方法 总被引：3，自引：0，他引：3
检索是基于案例推理(CBR)系统中的关键技术,本文把ART神经网络与案例多级索引技术结合起来,提出一种两级ART网络结构模型,为大型案例库建立了案例分类及检索模型,实现案例动态聚类与从类型到具体案例的索引,增强了系统的自学习、自适应能力,大大提高了案例分类和检索的效率。 相似文献
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Nieves R. Brisaboa Antonio Fari?a Susana Ladra Gonzalo Navarro 《Information Retrieval》2012,15(6):527-557
Word-based byte-oriented compression has succeeded on large natural language text databases, by providing competitive compression ratios, fast random access, and direct sequential searching. We show that by just rearranging the target symbols of the compressed text into a tree-shaped structure, and using negligible additional space, we obtain a new implicitly indexed representation of the compressed text, where search times are drastically improved. The occurrences of a word can be listed directly, without any text scanning, and in general any inverted-index-like capability, such as efficient phrase searches, can be emulated without storing any inverted list information. We experimentally show that our proposal performs not only much more efficiently than sequential searches over compressed text, but also than explicit inverted indexes and other types of indexes, when using little extra space. Our representation is especially successful when searching for single words and short phrases. 相似文献
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由于从事医学专业领域活动的多样性,专业读者与非专业读者、本单位读者与外单位读者、本地读者与远程用户在医学书目情报需求目的、需求类型、需求层次及需求行为均存在差异。为满足读者个性化书目情报需求,医学图书馆要提升本地资源与远程资源相结合的文献保障能力、Web 2.0支持下的书目情报技术服务能力、具有医学与信息管理背景的专家服务能力、医学书目情报深度知识服务能力。个性化医学书目情报服务策略包括:知识提供与知识获取技能相结合的策略、多渠道书目情报交流相结合的策略、需求驱动书目情报配置的策略、专家服务推动公共服务的策略。 相似文献
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《期刊图书馆员》2013,64(3-4):287-297
Summary ScienceDirect? has been developed by Elsevier Science to provide a databased, Web host environment for its journals and those of other participating publishers. The target is to create an integrated environment, which will permit efficient and transparent access to the scientific literature by integrating abstracting and indexing searching and by linking to other publishers' sites. 相似文献
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To prepare for a career, in which they keep up-to-date with current physical therapy procedures and health care trends, it is imperative that students become life-long learners. Four core competencies have been identified as skills to promote life-long learning: e-mail, professional electronic mailing lists (listservs), online data-base searching, and searching the World Wide Web. This paper discusses integrating the core competencies into the curriculum of a physical therapist assistant program through a collaborative effort between the physical therapist assistant program faculty and librarians. 相似文献
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Indiana University School of Medicine Library (IUSML) has traditionally been a high volume searching institution. The dramatic effect of CD-ROM on online end-user searching and the negligible effect on mediated searching was reported in an earlier study. This follow-up study reveals that the proportion of mediated searching has been drastically reduced from 94% in 1986/87 to 39% as of November 1989. Mediated searches are declining in absolute numbers as well. End-user searching, by contrast, has increased by 54% percent over the previous year. A related trend is the increased use of CD-ROM by the librarian as an alternative to mediated online searching. These trends are expected to continue as IUSML expands its CD-ROM operation to include other databases. As mediated searching declines, the librarian's role will increasingly include end-user training. 相似文献
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《Library & information science research》2005,27(2):249-263
The problem of language in Web searching has been discussed primarily in the area of cross-language information retrieval (CLIR). However, much CLIR research centers on investigation of the effectiveness of automatic translation techniques. The case study reported here explored bilingual user behaviors, perceptions, and preferences with respect to the capability of the Web as a multilingual information resource. Twenty-eight bilingual academic users from Myongji University in Korea were recruited for the study. Findings show that the subjects did not use Web search engines as multilingual tools. For search queries, they selected a language that represents their information need most accurately depending on the types of information task rather than choosing their first language. Subjects expressed concerns about the accuracy of machine translation of scholarly terminologies and preferred to have user control over multilingual Web searches. 相似文献
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在分析传统网络爬行器爬行算法的基础上,通过将隧道算法和网页页面分块技术相结合,指导专题爬行器进行爬行。通过4所高校门户网站的教育资源搜索实验表明,新的算法可以有效提高搜索效率。 相似文献
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Amritpal Kaur 《International Information and Library Review》2013,45(4):182-193
The article examines academics attitude towards e-journal use. A well structured questionnaire was designed to elicit the opinions of the users. Responses were gathered from 542 faculty members of five universities. The results of the study showed that the characteristics that affect the choice of e-format over print in order of preference are ‘faster access’, ‘available from desktop’, ‘convenience’, ‘remote access’, ‘timeliness’, ‘available at all times’, ‘hyperlinks’, ‘multi-user access’, ‘currency of information’, ‘inclusion of audio–video material’, ‘interactivity’ and ‘animation of graphics’. The characteristics that affect the choice of print format over electronic in order of priority are ‘physical comfort’, ‘portability’, ‘ability to underline’, ‘familiarity with format’ and ‘ability to browse’. A majority of the teachers use e-journals for ‘research’, ‘teaching’, ‘writing reports’, ‘current awareness’, ‘background research’ and ‘internal/external presentations’. The problems faced in accessing e-journals are ‘access difficulties’, ‘discomfort of reading from computer screen’, ‘lack of IT knowledge/skill’, ‘information overload’ etc. A majority of the teachers want future e-journals to have features such as ‘full text index of every article’, ‘searching capability across a wide range of journal articles’, ‘searching capability within an article, display relationship between a wide range of works’ and ‘links to multimedia files’, etc. On the basis of the findings, some suggestions are made for maximizing the use of e-journals. 相似文献