论循环比赛的名次排列

本文以离散数学中的图论方法,就循环比赛中的名次排列进行了研究与论证,有一定的借鉴意义。     

科学搜索引擎Scirus研究

科学搜索引擎Scirus是一种针对科学的、专业领域信息的搜索引擎。它帮助人们从浩如烟海的网络信息中准确快速地获得所需要的科学信息。Scirus凭着优秀的搜索表现,连续三年被“搜索引擎观察”评为最佳专业搜索引擎。本文介绍了Scirus的一些基本情况,并以《Scirus白皮书》为基础,研究Scirus如何能够准确地搜索到用户所需要的信息。     

Probabilistic relevance ranking for collaborative filtering

Collaborative filtering is concerned with making recommendations about items to users. Most formulations of the problem are specifically designed for predicting user ratings, assuming past data of explicit user ratings is available. However, in practice we may only have implicit evidence of user preference; and furthermore, a better view of the task is of generating a top-N list of items that the user is most likely to like. In this regard, we argue that collaborative filtering can be directly cast as a relevance ranking problem. We begin with the classic Probability Ranking Principle of information retrieval, proposing a probabilistic item ranking framework. In the framework, we derive two different ranking models, showing that despite their common origin, different factorizations reflect two distinctive ways to approach item ranking. For the model estimations, we limit our discussions to implicit user preference data, and adopt an approximation method introduced in the classic text retrieval model (i.e. the Okapi BM25 formula) to effectively decouple frequency counts and presence/absence counts in the preference data. Furthermore, we extend the basic formula by proposing the Bayesian inference to estimate the probability of relevance (and non-relevance), which largely alleviates the data sparsity problem. Apart from a theoretical contribution, our experiments on real data sets demonstrate that the proposed methods perform significantly better than other strong baselines.

高校图书馆竞争力评价及对策-基于52所高校的实证研究

高校图书馆竞争力正日益引起关注,为了更好地了解目前高校图书馆建设情况,选取了25所"985计划"和27所"211工程"高校作为研究对象,构建竞争力评价指标体系,并通过因子分析法对8个指标变量、52所高校进行分析,最终得出各高校图书馆竞争力综合排名。最后,采用聚类分析方法,针对不同层次的高校图书馆提出提高竞争力的对策。     

Ranking institutions within a discipline: The steep mountain of academic excellence

We present a novel algorithm to rank smaller academic entities such as university departments or research groups within a research discipline. The Weighted Top Candidate (WTC) algorithm is a generalisation of an expert identification method. The axiomatic characterisation of WTC shows why it is especially suitable for scientometric purposes. The key axiom is stability – the selected institutions support each other's membership. The WTC algorithm, upon receiving an institution citation matrix, produces a list of institutions that can be deemed experts of the field. With a parameter we can adjust how exclusive our list should be. By completely relaxing the parameter, we obtain the largest stable set – academic entities that can qualify as experts under the mildest conditions. With a strict setup, we obtain a short list of the absolute elite. We demonstrate the algorithm on a citation database compiled from game theoretic literature published between 2008–2017. By plotting the size of the stable sets with respect to exclusiveness, we can obtain an overview of the competitiveness of the field. The diagram hints at how difficult it is for an institution to improve its position.     

“全美最佳大学”排行榜的排行理念及其启示

《美国新闻与世界报道》每年9月所推出的"全美最佳大学"排行榜尽管是对美国国内的高等学校进行排名,但却在全球范围内享有盛誉。贯穿于"全美最佳大学"排行榜中的排行理念是其精髓所在,其分类排行、重视促进人才培养的评估指标、评估方法的客观性、为消费者服务的排行理念值得中国学习。     

Are you in h?

A new method of assessment of scientific papers, scientists, and scientific institutions was defined. The significance of a paper was assessed by the definition of the largest (the most prestigious) set, including that paper in its h-core. The sets of papers were defined by affiliation (country, city, university, department) or by subject (branches and sub-branches of science, journal). The inclusion of a paper in the h-core of certain set(s) was used as an indicator of the significance of that paper, and of the scientific output of its author(s), of their scientific institution(s), etc. An analogous procedure was used to assess the contribution of an individual to the scientific output of his/her scientific institution, branch of science, etc.     

A review of ranking approaches for semantic search on Web

With ever increasing information being available to the end users, search engines have become the most powerful tools for obtaining useful information scattered on the Web. However, it is very common that even most renowned search engines return result sets with not so useful pages to the user. Research on semantic search aims to improve traditional information search and retrieval methods where the basic relevance criteria rely primarily on the presence of query keywords within the returned pages. This work is an attempt to explore different relevancy ranking approaches based on semantics which are considered appropriate for the retrieval of relevant information. In this paper, various pilot projects and their corresponding outcomes have been investigated based on methodologies adopted and their most distinctive characteristics towards ranking. An overview of selected approaches and their comparison by means of the classification criteria has been presented. With the help of this comparison, some common concepts and outstanding features have been identified.     

Rickety numbers: Volatility of university rankings and policy implications

The most popular world university rankings are routinely taken at face value by media and social actors. While these rankings are politically influential, they are sensitive to both the conceptual framework (the set of indicators) and the modelling choices made in their construction (e.g., weighting or type of aggregation). A robustness analysis, based on a multi-modelling approach, aims to test the validity of the inference about the rankings produced in the Academic Ranking of World Universities (ARWU) of Shanghai Jiao Tong University and those produced by the UK's Times Higher Education Supplement (THES). Conclusions are drawn on the reliability of individual university ranks and on relative country or macro regional performance (e.g., Europe versus USA versus China) in terms of the number of top performing institutions. We find that while university and country level statistical inferences are unsound, the inference on macro regions is more robust. The paper also aims to propose an alternative ranking which is more dependant on the framework than on the methodological choices.     

中国武术散打王争霸赛积分排名挑战赛制的研究

针对解决中国武术散打王争霸赛与锦标赛赛制中存在的矛盾,既保证散打王参赛运动员的主体,又兼顾了锦标赛优秀运动员的参赛;既保证明星运动员的出场率,保证赛事水平、确保收视率,又能通过新赛制不断地推出新人.以散打王、锦标赛,以及相关项目的赛制为研究对象,通过积分排名的相应计算办法,确定参赛的运动员范围.进一步根据散王打竞赛市场特性的整体构思,设计新的赛制结构和进度,为探索符合市场要求的散打赛制体系提供理论依据.