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11.
随着校园网的快速发展,产生了海量信息,怎样利用数据挖掘技术根据校园网用户的访问日志挖掘出有价值的信息,是值得深入研究的。作者首先介绍了Web日志挖掘技术的主要内容,再深入研究在校园网信息处理方面的应用,重点以遵义师范学院校园网为实例,使用关联规则进行研究分析,探讨出用户的兴趣与偏好,从而更好地为学校教学管理服务。  相似文献   
12.
通过语篇补全测试,调查中国英语学习者对探询型请求子策略的选择。结果发现:学习者在请求主体策略选择上呈现与英语母语者相同的序列;学习者在请求子策略选择上存在过多或不当使用某些情态词,某些话句类型使用单一的情况;角色指向性的选择上,以听话者为指向的比率较高。这些特点表明文化间既具有相通性也存在文化相异,需要在教学中积极开展明示语用教学,重视学生语言能力的培养。  相似文献   
13.
The Inductive Query By Example (IQBE) paradigm allows a system to automatically derive queries for a specific Information Retrieval System (IRS). Classic IRSs based on this paradigm [Smith, M., & Smith, M. (1997). The use of genetic programming to build Boolean queries for text retrieval through relevance feedback. Journal of Information Science, 23(6), 423–431] generate a single solution (Boolean query) in each run, that with the best fitness value, which is usually based on a weighted combination of the basic performance criteria, precision and recall.  相似文献   
14.
This paper examines the factors affecting the performance of global query expansion based on term co-occurrence data and suggests a way to maximize the retrieval effectiveness. Major parameters to be optimized through experiments are term similarity measure and the weighting scheme of additional terms. The evaluation of four similarity measures tested in query expansion reveal that mutual information and Yule's Y, which emphasize low frequency terms, achieve better performance than cosine and Jaccard coefficients that have the reverse tendency. In the evaluation of three weighting schemes, similarity weight performs well only with short queries, whereas fixed weights of approximately 0.5 and similarity rank weights were effective with queries of any length. Furthermore, the optimal similarity rank weight achieving the best overall performance seems to be the least affected by test collections and the number of additional terms. For the efficiency of retrieval, the number of additional terms needs not exceed 70 in our test collections, but the optimal number may vary according to the characteristics of the similarity measure employed.  相似文献   
15.
In the KL divergence framework, the extended language modeling approach has a critical problem of estimating a query model, which is the probabilistic model that encodes the user’s information need. For query expansion in initial retrieval, the translation model had been proposed to involve term co-occurrence statistics. However, the translation model was difficult to apply, because the term co-occurrence statistics must be constructed in the offline time. Especially in a large collection, constructing such a large matrix of term co-occurrences statistics prohibitively increases time and space complexity. In addition, reliable retrieval performance cannot be guaranteed because the translation model may comprise noisy non-topical terms in documents. To resolve these problems, this paper investigates an effective method to construct co-occurrence statistics and eliminate noisy terms by employing a parsimonious translation model. The parsimonious translation model is a compact version of a translation model that can reduce the number of terms containing non-zero probabilities by eliminating non-topical terms in documents. Through experimentation on seven different test collections, we show that the query model estimated from the parsimonious translation model significantly outperforms not only the baseline language modeling, but also the non-parsimonious models.  相似文献   
16.
This paper examines the meaning of context in relation to ontology based query expansion and contains a review of query expansion approaches. The various query expansion approaches include relevance feedback, corpus dependent knowledge models and corpus independent knowledge models. Case studies detailing query expansion using domain-specific and domain-independent ontologies are also included. The penultimate section attempts to synthesise the information obtained from the review and provide success factors in using an ontology for query expansion. Finally the area of further research in applying context from an ontology to query expansion within a newswire domain is described.  相似文献   
17.
The term mismatch problem in information retrieval is a critical problem, and several techniques have been developed, such as query expansion, cluster-based retrieval and dimensionality reduction to resolve this issue. Of these techniques, this paper performs an empirical study on query expansion and cluster-based retrieval. We examine the effect of using parsimony in query expansion and the effect of clustering algorithms in cluster-based retrieval. In addition, query expansion and cluster-based retrieval are compared, and their combinations are evaluated in terms of retrieval performance by performing experimentations on seven test collections of NTCIR and TREC.  相似文献   
18.
Intelligent use of the many diverse forms of data available on the Internet requires new tools for managing and manipulating heterogeneous forms of information. This paper uses WHIRL, an extension of relational databases that can manipulate textual data using statistical similarity measures developed by the information retrieval community. We show that although WHIRL is designed for more general similarity-based reasoning tasks, it is competitive with mature systems designed explicitly for inductive classification. In particular, WHIRL is well suited for combining different sources of knowledge in the classification process. We show on a diverse set of tasks that the use of appropriate sets of unlabeled background knowledge often decreases error rates, particularly if the number of examples or the size of the strings in the training set is small. This is especially useful when labeling text is a labor-intensive job and when there is a large amount of information available about a particular problem on the World Wide Web.
Haym HirshEmail:
  相似文献   
19.
研究利用Web日志文件来进行CRM数据挖掘是很有实际应用价值的,本文从这种实际需求出发,提出在数据预处理过程中使用启发式规则来识别用户,并介绍了一种基于IIS本身配置进行数据采集的方法。  相似文献   
20.
GVLIS船舶航行报告系统可以同时管理数百条全球航行的船舶。安装在每条船上的"GVLIS船上子系统"对每个航次或航段中16类不同事件中的每个事件,可允许录入多达200个不同的数据项,并生成报告,发送到总部子系统。"GVLIS总部子系统"管理船舶报告数据库,并对每条船舶的数据进行检查和分析,及时发出警示信息和分析报告,以便管理人员采取必要的措施。GVLIS是典型的以"操作事件"驱动的应用软件。本文介绍的这类软件的设计方法是规定在设计系统模块时应包括功能描述,用户界面说明,模块数据说明,模块处理过程说明等。  相似文献   
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