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Czesław Daniłowicz 《Information processing & management》1983,19(3):159-163
Principles for determining the profile of a system user have been presented. These principles are based on the analysis of co-occurrence of index terms in queries and pertinent documents. Moreover, a procedure for determining index term weights on the basis of user profiles has been introduced. The information value of the index term weights depends on the degree of homogeneity of the system users. 相似文献
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Traditional measures of retrieval effectiveness, of which the recall ratio is an outstanding example, are strongly influenced by the relevance properties of unexamined documents—documents with which the system user has no direct contact. Such an influence is awkward to explain in traditional terms, but is readily justified within the broader framework of a utility-theoretic approach. The utility-theoretic analysis shows that unexamined documents can be important in theory, but usually are not when it is the statistics of large samples that are of interest. It is concluded that the traditional concern with the relevance or nonrelevance of unexamined documents is misplaced, and that traditional measures of effectiveness should be replaced by estimates of the direct utility of the examined documents. 相似文献
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查收查引服务中存在文献未检到现象,文献检索不到既影响用户使用,也说明图书馆需要提高服务质量.文章从数据库商、用户、检索人员3个角度针对性地提出了相关策略和建议. 相似文献
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Thomas R. Kochtanek 《Information processing & management》1982,18(1):33-39
An algorithm based upon reference and citation links is shown to improve effectiveness in compiling a bibliography on a cross-disciplinary medical subject area. Sets of documents are generated and compared to a set of documents identified by researchers as being relevant to their informational needs. The result is a rank ordered list of documents as they relate to the chosen entry document. The algorithm is described as a generalized technique applicable to any cross-disciplinary informational query which has as its objective the compilation of a bibliography of pertinent documents. 相似文献
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Paul Duguid 《The Information Society》2005,21(2):109-118
Community of practice theory is inherently a social theory. As such it is distinct from more individualist accounts of human behavior, such as mainstream economics. Consequently, community of practice theory and economics favor different accounts of knowledge. Taking a community of practice perspective, this article challenges economists' attempts to reduce knowledge to information held by individuals and to reject tacit knowledge as mere uncodified explicit knowledge. The essay argues that Polanyi's notion of a tacit dimension affected numerous disciplines (including economics) because it addressed aspects of learning and identity that conventional social sciences overlooked. The article situates knowledge, identity, and learning within communities and points to ethical and epistemic entailments of community practice. In so doing it attempts to limit, rather than expand, the scope of community of practice analysis and to stress the difference, rather than the commonalities, between this and other apparently congenial forms of social analysis. 相似文献
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This study examined the development of individual social capital in a distributed learning community. Feld's theory of focused choice predicts that the formation of network ties is constrained by contextual factors that function as foci of activities. In our research, we examined how group assignment and location could function as such foci to influence the development of individual social capital in a distributed learning community. Given that networks with different content flows may possess different properties, we examined two different types of networks—task-related instrumental networks and non-task-related expressive networks. A longitudinal research design was used to evaluate the evolution of networks over time. Hypotheses were tested using a sample of 32 students enrolled in a distributed learning class. The results show strong support for Feld's theory. While serving as foci of activities to organize social interactions, both group assignment and geographic separation can also function to fragment a learning community. 相似文献
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This paper presents an investigation about how to automatically formulate effective queries using full or partial relevance information (i.e., the terms that are in relevant documents) in the context of relevance feedback (RF). The effects of adding relevance information in the RF environment are studied via controlled experiments. The conditions of these controlled experiments are formalized into a set of assumptions that form the framework of our study. This framework is called idealized relevance feedback (IRF) framework. In our IRF settings, we confirm the previous findings of relevance feedback studies. In addition, our experiments show that better retrieval effectiveness can be obtained when (i) we normalize the term weights by their ranks, (ii) we select weighted terms in the top K retrieved documents, (iii) we include terms in the initial title queries, and (iv) we use the best query sizes for each topic instead of the average best query size where they produce at most five percentage points improvement in the mean average precision (MAP) value. We have also achieved a new level of retrieval effectiveness which is about 55–60% MAP instead of 40+% in the previous findings. This new level of retrieval effectiveness was found to be similar to a level using a TREC ad hoc test collection that is about double the number of documents in the TREC-3 test collection used in previous works. 相似文献
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William S. Cooper 《Information processing & management》1976,12(6):367-375
Traditional measures of retrieval effectiveness, of which the recall ratio is an outstanding example, are strongly influenced by the relevance properties of unexamined documents—documents with which the system user has no direct contact. Such an influence is awkward to explain in traditional terms, but is readily justified within the broader framework of a utility-theoretic approach. The utility-theoretic analysis shows that unexamined documents can be important in theory, but usually are not when it is the statistics of large samples that are of interest. It is concluded that the traditional concern with the relevance or nonrelevance of unexamined documents is misplaced, and that traditional measures of effectiveness should be replaced by estimates of the direct utility of the examined documents. 相似文献
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《Information processing & management》2001,37(4):623-637
One of the most important problems in information retrieval is determining the order of documents in the answer returned to the user. Many methods and algorithms for document ordering have been proposed. The method introduced in this paper differs from them especially in that it uses a probabilistic model of a document set. In this model documents are regarded as states of a Markov chain, where transition probabilities are directly proportional to similarities between documents. Steady-state probabilities reflect similarities of particular documents to the whole answer set. If documents are ordered according to these probabilities, at the top of a list there will be documents that are the best representatives of the set, and at the bottom those which are the worst representatives. The method was tested against databases INSPEC and Networked Computer Science Technical Reference Library (NCSTRL). Test results are positive. Values of the Kendall rank correlation coefficient indicate high similarity between rankings generated by the proposed method and rankings produced by experts. Results are comparable with rankings generated by the vector model using standard weighting schema tf·idf. 相似文献
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A common approach to Lyapunov's stability control is to design a controller such that a Lyapunov function can be derived for the control system to ensure stability. This procedure often leads to a discontinuous controller. When the controller is implemented, the discontinuous terms are replaced with continuous functions to avoid chattering of the control signal. Two associated problems have been overlooked during this procedure. One is that discontinuous control systems are non-smooth, which violates the fundamental assumptions of solution theories and the applicability of Lyapunov's stability theory is questionable. Another problem is that the replacement of discontinuous terms may weaken stability, which can be critical. In this paper, we discuss proper stability analysis of discontinuous control systems using the extended Lyapunov's second method based on Filippov's solution concept for non-smooth systems. We further propose to utilize the concept of Lyapunov exponents to quantitatively analyze the stability of continuous control systems obtained by replacing the discontinuous terms in the discontinuous controllers. An example involving the stabilization of a two-link non-fixed-base robotic manipulator is presented for demonstration. This research fills the gap in designing continuous Lyapunov's stability controllers regarding limited available Lyapunov functions. 相似文献
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本文根基商业模式内涵,构建商业模式结构模型,依据发展历程收集5家代表案例企业时间序列新闻文献和数据资料,运用内容分析法结构化分析文献资料,提炼互联网业商业模式动态演化规律和演化路径。研究显示：互联网业商业模式中,价值定义、价值实现、价值创造与传递三大构件的主导地位依次更替,对应呈现出客户价值实现、企业价值实现和网络价值实现的纵向三阶段演化模型,三阶段模型在时间跨度和运营绩效上与企业生命周期的创业期、发展期和成熟期很好吻合,商业模式的三大构件同样呈现出动态演化特征。本研究试图打开商业模式的组成结构黑箱,将商业模式的设计理论从静态视角升级到动态层面,为互联网业的发展给出可行的实践参考。 相似文献
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Applying text mining techniques to legal issues has been an emerging research topic in recent years. Although a few previous studies focused on assisting professionals in the retrieval of related legal documents, to our knowledge, no previous studies could provide relevant statutes to the general public using problem statements. In this work, we design a text mining based method, the three-phase prediction (TPP) algorithm, which allows the general public to use everyday vocabulary to describe their problems and find pertinent statutes for their cases. The experimental results indicate that our approach can help the general public, who are not familiar with professional legal terms, to acquire relevant statutes more accurately and effectively. 相似文献
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[目的/意义]已有研究对文献耦合关系和同被引关系比较的研究较少，本文比较两种关系在文献间建立联系的差异，并且比较耦合/同被引强度与文献相似度的相关性，分析耦合分析和同被引分析各自更适合哪些方面的应用。[方法/过程]根据复杂网络理论，构建文献耦合网络和同被引网络，实证比较文献耦合网络和同被引网络的拓扑性质。利用QAP关联分析，研究耦合关系、同被引关系与文献内容相似度的关系。[结果/结论]网络拓扑结构分析表明，耦合关系在文献之间建立的联系更普遍而且更稳定，更利于检索被引用次数较少的大多数文献；同被引关系在高被引文献之间建立的联系更紧密，利于检索和确定领域内的核心文献。QAP关联分析表明耦合强度和文献相似度的相关性更强，在文献聚类分析研究主题时，耦合强度更可靠。 相似文献
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M. Mercedes Martínez-Gonzlez Pablo de la Fuente 《Information processing & management》2007,43(6):1808
References to parts of structured documents use their structure to locate the piece of document which is the reference target. On the other hand, XML has become an increasingly important language for structured documents. One of its most important related languages is XPath, the language that permits fragments of XML documents to be selected. In this article we present a methodology, and an application case, to automatically extract and solve references to fragments of structured documents. This approach combines structure manipulation and information extraction, to enhance reference extraction tools by improving the precision of the references extracted. We take advantage of XML markup to locate the position within the structure in which the references are found. The use of XPath, one of the most important XML related languages, for reference resolution is original: the resolution tool automatically builds XPath expressions. This proposal is inspired (and implemented) from our work with legislative documents. 相似文献
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《Information processing & management》2020,57(4):102239
Expert finding addresses the task of retrieving and ranking talented people on the subject of user query. It is a practical issue in the Community Question Answering networks. Recruiters looking for knowledgeable people for their job positions are the most important clients of expert finding systems. In addition to employee expertise, the cost of hiring new staff is another significant concern for organizations. An efficient solution to cope with this concern is to hire T-shaped experts that are cost-effective. In this study, we have proposed a new deep model for T-shaped experts finding based on Convolutional Neural Networks. The proposed model tries to match queries and users by extracting local and position-invariant features from their corresponding documents. In other words, it detects users’ shape of expertise by learning patterns from documents of users and queries simultaneously. The proposed model contains two parallel CNN’s that extract latent vectors of users and queries based on their corresponding documents and join them together in the last layer to match queries with users. Experiments on a large subset of Stack Overflow documents indicate the effectiveness of the proposed method against baselines in terms of NDCG, MRR, and ERR evaluation metrics. 相似文献
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Tadeusz Radecki 《Information processing & management》1976,12(5):319-326
The object of this paper is to present a new kind of approach to the problem of information system effectiveness evaluation as based on the theory of fuzzy sets. On the basis of this theory, the concepts of relevance and pertinence, which are the basic concepts used in determining the indices of information system effectiveness evaluation, have been defined. Assuming that in evaluating the effectiveness of information systems, one should consider separately the problem of quality evaluation of the transformation of the contents of documents and information requests into their search patterns and the problem of quality evaluation of the process of profile control of a document set of the information system, definitions have been given of parameters of quality evaluation of the transformation of the contents of documents and information requests into their search patterns with regard to a given information request as well as of parameters of quality evaluation of the process with regard to the whole set of information requests under examination. Besides, parameters of quality evaluation of the process of profile control of a document set of the information system have been defined. The parameters of effectiveness evaluation of information systems put forward in this paper take account of the fact that both evaluation of the relevance and evaluation of the pertinence of documents are of a continuous character. 相似文献