基于WEB的全文搜索引擎系统设计与实现

随着企事业单位信息资源的膨胀,如何优化企事业信息资源检索越发重要。从分析开源搜索引擎lucene出发,设计了一种基于SSlweb框架和lucene全文搜索工具包的全文搜索引擎系统,实现了以B／S模式远程搜索服务器文件,满足局域网内对文档搜索的需求,实验结果表明该搜索引擎有效地提高信息检索的准确度。     

A knowledge-based semantic framework for query expansion

Searching for relevant material that satisfies the information need of a user, within a large document collection is a critical activity for web search engines. Query Expansion techniques are widely used by search engines for the disambiguation of user’s information need and for improving the information retrieval (IR) performance. Knowledge-based, corpus-based and relevance feedback, are the main QE techniques, that employ different approaches for expanding the user query with synonyms of the search terms (word synonymy) in order to bring more relevant documents and for filtering documents that contain search terms but with a different meaning (also known as word polysemy problem) than the user intended. This work, surveys existing query expansion techniques, highlights their strengths and limitations and introduces a new method that combines the power of knowledge-based or corpus-based techniques with that of relevance feedback. Experimental evaluation on three information retrieval benchmark datasets shows that the application of knowledge or corpus-based query expansion techniques on the results of the relevance feedback step improves the information retrieval performance, with knowledge-based techniques providing significantly better results than their simple relevance feedback alternatives in all sets.     

两种EGR率标定方法下柴油机工作特性的对比

EGR成为降低发动机NOx排放的最有效方式之一,但标定其再循环量的重要参数EGR率的标定方法却有非常多种。针对这种情况,进行了柴油机在同等EGR率数值下的不同EGR率标定方法的柴油机工作特性的对比研究。研究结果发现,不同EGR率标定方法下,柴油机工作参数的变化趋势是一致的,区别在于标方法不同时,对工作参数的影响程度不同。     

基于Jess规则的数据库通知服务

提出一种实现数据库通知服务的技术框架,使用Jess规则代替SQL编码来表达用户的数据监控策略,规则执行时先由规则解释器将规则翻译成SQL语句然后执行.使用这种方法,数据监控策略易于理解和接受,修改方便;其次,可在规则解释器中实现异构数据库系统之间的关联通知服务;最后,Jess规则还可以进行复杂的推理,实现通知业务的智能化.     

搜索引擎Google的检索功能及PageRank技术分析

本文介绍了搜索引擎Google的特点和检索功能，并重点介绍了其PageRank专利技术的概念及计算方法。     

关于自然语言检索问题

自然语言检索当前仅在关键词检索的层次上已经实现，重点分析了全文检索所适应和不适应的检索要求及其评价，用分析说明了当前关于自然语言检索的主流观点的不切实际，指出自然语言检索的发展方向是与情报检索语言结合和融合。     

Dictionary-based text categorization of chemical web pages

A new dictionary-based text categorization approach is proposed to classify the chemical web pages efficiently. Using a chemistry dictionary, the approach can extract chemistry-related information more exactly from web pages. After automatic segmentation on the documents to find dictionary terms for document expansion, the approach adopts latent semantic indexing (LSI) to produce the final document vectors, and the relevant categories are finally assigned to the test document by using the k-NN text categorization algorithm. The effects of the characteristics of chemistry dictionary and test collection on the categorization efficiency are discussed in this paper, and a new voting method is also introduced to improve the categorization performance further based on the collection characteristics. The experimental results show that the proposed approach has the superior performance to the traditional categorization method and is applicable to the classification of chemical web pages.     

搜索引擎的智能检索机制

探讨搜索引擎的一些智能检索机制,包括基于概念匹配的检索,对网络信息进行深层次挖掘,分析并预测用户的信息需求和提供个性化、专业化的检索服务。     

《发动机原理及构造》课程教学方法的探讨

分析并比较了传统教学方法、现代教学方法、互动式教学方法在《发动机原理及构造》课程的教学中应用时的优缺点，提出了一种全新的互动式现场教学方法。这种教学方法能充分发挥教师、学生的积极性，提高了课堂教学的效果，并培养了学生的动手能力和创新能力。     

基于分类目录的元搜索引擎模型的提出与实现

本文首先给出了搜索引擎的定义、工作机制及分类 ,并指出了目前搜索引擎的不足 ,针对这些不足提出了几点改进意见 ,实现了一种基于分类目录的元搜索引擎。最后对该搜索引擎进行了评估和展望