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.     

等比级数在级数中的应用

文章阐述了等比级数∞n=0axn=a1-x(|x|<1)在求幂级数的和函数以及将函数展开成幂级数中的重要作用。     

浅析巴西私立高等教育扩张对教育公平的影响

近年来,巴西私立高等教育急剧扩张,但由于高昂的学费以及学位价值与支出的课程费用的不相称,大多数巴西人并不能就读私立大学。这不仅产生了教育的质量问题,而且也出现了教育不公平的现象。尽管私立高等教育中的助学贷款和政府补贴有所增加,但教育公平仍不能真正实现。     

铜基电子封装材料研究进展

介绍了国内外铜基电子封装材料的研究现状及最新发展动态,指出了目前我国新型铜基电子封装材料研究中所存在的问题及进一步完善的措施,预测了电子封装用铜基复合材料的发展趋势和应用前景．未来的铜基电子封装材料将朝着高性能、低成本、轻量化和集成化的方向发展．     

高职院校图书馆读者服务内容的拓展与质量保证策略

在现代信息技术环境下,图书馆读者服务工作面新的挑战,高校图书馆应关注读者需求、丰富馆藏资源、开展“称心”“放心”“欢心”服务、把图书馆建成学生社会实践基地;坚持“以人为本”、强化馆员主动服务意识、不断提升馆员的服务能力。     

扩招形势下以"自主学习"为中心的英语课堂设计思路

扩招给大学英语课堂教学带来的诸多问题,迫使英语课堂必须转向以"自主学习"为中心的模式.针对扩招带给课堂教学带来的影响,有针对性地设计课堂教学的思路,会对英语教学改革带来意想不到的收获.     

冷冻技术对休闲油炸豆类食品品质的影响

本课题根据冷冻技术可使食品（原料）体积膨胀和品质变化等特点,研究确定了冷冻技术对大豆等油炸休闲食品品质变化的影响程度,并进行了品质分析。     

Research in non-equalization machining method for spatial cam

Many kinds of devices with cam have been widely used in various mechanical equipments. However, non-equalization machining for spatial cam trough remains to be a difficult problem. This paper focuses on the analysis of running conditions and machining processes of spatial cam with oscillating follower. We point out the common errors in the biased distance cutting. By analyzing the motion of oscillating follower of spatial cam, we present a new 3D curve expansion model of spatial cam trough-outline. Based on this model, we have proposed a machining method for trochoidal milling with non-equalization diameter cutter. This new method has led to a creative and effective way for non-equalization diameter machining for spatial cam with oscillating follower.     

高职百万扩招助力职业教育精准扶贫

高职院校百万扩招有利于扩大职业教育精准扶贫覆盖面,通过职业教育大扩招政策红利的杠杆作用,面向贫困群体开展精准培养和精准帮扶,促进扶贫对象在技能技术、精神、就业创业能力等方面快速提升,实现贫困群体的“精准就业”和“精准脱贫”。新时代高职院校的百万大扩招是我国精准扶贫补短板的重要战略举措,具有重要的意义和使命,为我国打赢扶贫攻坚战提供坚实的软实力支撑。