航空发动机控制系统设计课程教学用仿真试验平台建设的思考与建议

本文对航空发动机控制系统设计课程实验教学提出了新的建议和思考。随着国际先进航空发动机控制新技术的发展,基于快速原型的发动机控制系统以及系统综合控制规律设计方法已成为必然趋势,航空发动机控制系统设计专业教学必须做出适应性的对策与措施,以满足教学内容对专业发展需求。借助一些关键发动机仿真试验平台的建设,通过课程实验环节使得学生熟悉了解航空发动机控制系统设计新方法,是一条可行的航空发动机控制专业教学改革途径。     

1997-2011年我国搜索引擎研究论文统计分析

对1997-2011年这15年间刊载在我国18种图书馆学、情报学核心期刊上的有关搜索引擎研究的论文进行定量分析,分析的内容主要包括:论文发表年代分布、论文产出期刊源分布、基金课题项目分布、论文及作者的地区分布和系统分布、作者人均发文量、核心作者的确定、核心作者的职称比例、学历比例以及论文的主题分布等,从而可以了解我国搜索引擎研究的状况。     

Distributed search based on self-indexed compressed text

Query response times within a fraction of a second in Web search engines are feasible due to the use of indexing and caching techniques, which are devised for large text collections partitioned and replicated into a set of distributed-memory processors. This paper proposes an alternative query processing method for this setting, which is based on a combination of self-indexed compressed text and posting lists caching. We show that a text self-index (i.e., an index that compresses the text and is able to extract arbitrary parts of it) can be competitive with an inverted index if we consider the whole query process, which includes index decompression, ranking and snippet extraction time. The advantage is that within the space of the compressed document collection, one can carry out the posting lists generation, document ranking and snippet extraction. This significantly reduces the total number of processors involved in the solution of queries. Alternatively, for the same amount of hardware, the performance of the proposed strategy is better than that of the classical approach based on treating inverted indexes and corresponding documents as two separate entities in terms of processors and memory space.     

Amount of invested mental effort (AIME) in online searching

This research investigates how people’s perceptions of information retrieval (IR) systems, their perceptions of search tasks, and their perceptions of self-efficacy influence the amount of invested mental effort (AIME) they put into using two different IR systems: a Web search engine and a library system. It also explores the impact of mental effort on an end user’s search experience. To assess AIME in online searching, two experiments were conducted using these methods: Experiment 1 relied on self-reports and Experiment 2 employed the dual-task technique. In both experiments, data were collected through search transaction logs, a pre-search background questionnaire, a post-search questionnaire and an interview. Important findings are these: (1) subjects invested greater mental effort searching a library system than searching the Web; (2) subjects put little effort into Web searching because of their high sense of self-efficacy in their searching ability and their perception of the easiness of the Web; (3) subjects did not recognize that putting mental effort into searching was something needed to improve the search results; and (4) data collected from multiple sources proved to be effective for assessing mental effort in online searching.     

The Nature and Functions of Meta-tags: Covert Infringement of Trademarks and Other Issues

Meta-tags are one of the 'associational tools' considered essential to the operation of the World Wide Web. Their significance has been highlighted by recent controversies in the United States which focus on one of their important functions, i.e. as indices of websites which search engines read and rely upon in looking for the appropriate content relative to queries submitted to them. This article deals with the effect of meta-tags on the intellectual property rights of website owners. The author presents a critical survey of the American meta-tag cases and offers an Australian perspective.     

网络环境下大学图书馆馆员搜商的培养

通过简述搜商的概念,指明网络社会大学图书馆员搜商培养的必然趋势,分析了大学图书馆在搜商培养方面的优势条件。从而进一步论述图书馆员搜商培养应该掌握的三项内容。参考文献5。     

Knock prediction for dual fuel engines by using a simplified combustion model

The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions. Project (No. 50106014) supported by the National Natural Science Foundation of China     

基于链接分析的网络信息资源评价研究

在网络信息资源的评价中,链接分析主要作为一种定量评价方法,通常与定性方法相结合,构成综合性的评价指标体系。论文阐述了国内外链接分析的发展过程及现状,并对链接分析在网络信息资源评价中的具体应用进行了分析。     

基于Multi-Agent跨库检索系统的设计与实现

借鉴元搜索引擎的原理，设计一个基于Multi-Agent的跨库检索系统。利用界面Agent、协作Agent、汇总Agent和检索代理Agent来实现系统的智能部件，多个Agent之间的通信通过协作Agent进行协作和交互，共同完成检索任务。同时对跨库检索系统的关键技术进行研究和讨论。     

谷歌数字图书馆研究现状综述

综述国内外学者对谷歌数字图书馆法律问题研究、竞争与反垄断研究、影响研究的现状,认为国内外学者对谷歌数字图书馆的研究均存在不足,国内学者对谷歌反垄断与竞争、和解协议、optout等众多领域未给予关注或研究深度不足,对我国版权法的完善未给出具有建设性的意见等,并提出相应建议。