搜索引擎的发展概况与趋势

搜索引擎是随着网上信息不断丰富应运而生的一种检索工具。1994年,Internet上诞生了第一个搜索引擎W ebCraw ler,通过对网页做索引来提供检索服务。2000年,Google的出现使搜索引擎市场发生了新的变化。近年来,中文搜索引擎的发展快,数量多。搜索引擎的发展有以下趋势:数据库小型化,专业化;强化全文检索功能;检索智能化、服务个性化;语种多样化;元搜索引擎的发展;搜索服务等。     

Relationships between the use of test results and US students’ academic performance

In this study, we examined relationships between the use of test results and US students’ math, reading, and science performance in the Programme for International Student Assessment (PISA) 2009. Based on a literature review, we hypothesized that the 16 items in the PISA school questionnaire, which are related to the use of test results, can be categorized according to 4 factors. We validated this hypothesized factor structure using a confirmatory factor analysis and then obtained composite scores for each factor. As revealed by a multilevel analysis, when student and school demographic variables were controlled for, using test results to hold schools accountable to authority and the public was significantly positively related to students’ performance across all 3 subjects. No statistically significant relationship, however, was detected between students’ performance and the following uses of test scores: informing parents of their children’s performance, providing information for instructional purposes, and evaluating teachers and principals.     

世界高水平男排不同进攻战术打法运用效果的定量分析

采用录像统计、数理统计等研究方法,对第29届奥运会排球赛的男子八强的最后八场比赛进行战术统计,定量描述了高水平男排比赛中进攻战术打法运用的数量与效果。对男排所有进攻战术打法运用的数量和效果的定量研究,能为教练员在以后的比赛和训练中选择合理有效的进攻战术提供科学的理论参考依据。     

文化哲学的文化视阈下的合法性探析

文化哲学具有文化性与哲学性,文化性是它的基础。文化哲学的文化性体现于它在文化视阈下,文化程序的纵向展开的可能性,也就是文化的发生、发展和文化成果。在文化性与哲学性的不同维度的对话中,文化哲学达到了合法的可能性。     

智能搜索引擎与数字图书馆个性化服务

智能搜索引擎基于知识(概念)层面实行信息检索，以较强的自然语言理解和知识处理能力，表现出良好的个性化信息服务特色。因此，智能搜索引擎应用于数字图书馆个性化服务体系，不仅有效发挥前者数据挖掘、知识发现的功能，同时能较大地加深后者的主动性、智能性优势。     

A heuristic hierarchical scheme for academic search and retrieval

We present PubSearch, a hybrid heuristic scheme for re-ranking academic papers retrieved from standard digital libraries such as the ACM Portal. The scheme is based on the hierarchical combination of a custom implementation of the term frequency heuristic, a time-depreciated citation score and a graph-theoretic computed score that relates the paper’s index terms with each other. We designed and developed a meta-search engine that submits user queries to standard digital repositories of academic publications and re-ranks the repository results using the hierarchical heuristic scheme. We evaluate our proposed re-ranking scheme via user feedback against the results of ACM Portal on a total of 58 different user queries specified from 15 different users. The results show that our proposed scheme significantly outperforms ACM Portal in terms of retrieval precision as measured by most common metrics in Information Retrieval including Normalized Discounted Cumulative Gain (NDCG), Expected Reciprocal Rank (ERR) as well as a newly introduced lexicographic rule (LEX) of ranking search results. In particular, PubSearch outperforms ACM Portal by more than 77% in terms of ERR, by more than 11% in terms of NDCG, and by more than 907.5% in terms of LEX. We also re-rank the top-10 results of a subset of the original 58 user queries produced by Google Scholar, Microsoft Academic Search, and ArnetMiner; the results show that PubSearch compares very well against these search engines as well. The proposed scheme can be easily plugged in any existing search engine for retrieval of academic publications.     

A study of results overlap and uniqueness among major Web search engines

The performance and capabilities of Web search engines is an important and significant area of research. Millions of people world wide use Web search engines very day. This paper reports the results of a major study examining the overlap among results retrieved by multiple Web search engines for a large set of more than 10,000 queries. Previous smaller studies have discussed a lack of overlap in results returned by Web search engines for the same queries. The goal of the current study was to conduct a large-scale study to measure the overlap of search results on the first result page (both non-sponsored and sponsored) across the four most popular Web search engines, at specific points in time using a large number of queries. The Web search engines included in the study were MSN Search, Google, Yahoo! and Ask Jeeves. Our study then compares these results with the first page results retrieved for the same queries by the metasearch engine Dogpile.com. Two sets of randomly selected user-entered queries, one set was 10,316 queries and the other 12,570 queries, from Infospace’s Dogpile.com search engine (the first set was from Dogpile, the second was from across the Infospace Network of search properties were submitted to the four single Web search engines). Findings show that the percent of total results unique to only one of the four Web search engines was 84.9%, shared by two of the three Web search engines was 11.4%, shared by three of the Web search engines was 2.6%, and shared by all four Web search engines was 1.1%. This small degree of overlap shows the significant difference in the way major Web search engines retrieve and rank results in response to given queries. Results point to the value of metasearch engines in Web retrieval to overcome the biases of individual search engines.     

搜索力经济研究

目前,由搜索引擎所引领的另类网络虚拟经济形态一“搜索力经济”正在迅速崛起。作为互联网新经济的核心价值,搜索力正引领着互联网的现在和未来。本文将对这一“热点区域”对“搜索力经济”的概念、出现原因及引发的变革等相关问题进行分析,帮助读者对互联网的新领域有更深刻的了解。     

垂直网站及其信息服务模式

The paper introduces vertical portals and their information service modes,analyzes the inevitability of their emergence and development, and finally gives some suggestions as to how to do a good job in providing information service through vertical portals.     

基于WEB挖掘的用户个性化配置方案研究

为每一位Web用户提供个性化服务已经成为电子商务网站发展的趋势。本文首先分析了Web挖掘的基本概念和工作流程，在此基础上提出了基于Web访问信息挖掘的用户个性化配置方案模型，并对模型实现的关键技术及其在电子商务中的应用进行了研究。