Inverted Index Compression Using Word-Aligned Binary Codes

We examine index representation techniques for document-based inverted files, and present a mechanism for compressing them using word-aligned binary codes. The new approach allows extremely fast decoding of inverted lists during query processing, while providing compression rates better than other high-throughput representations. Results are given for several large text collections in support of these claims, both for compression effectiveness and query efficiency.     

Scale and Translation Invariant Collaborative Filtering Systems

Collaborative filtering systems are prediction algorithms over sparse data sets of user preferences. We modify a wide range of state-of-the-art collaborative filtering systems to make them scale and translation invariant and generally improve their accuracy without increasing their computational cost. Using the EachMovie and the Jester data sets, we show that learning-free constant time scale and translation invariant schemes outperforms other learning-free constant time schemes by at least 3% and perform as well as expensive memory-based schemes (within 4%). Over the Jester data set, we show that a scale and translation invariant Eigentaste algorithm outperforms Eigentaste 2.0 by 20%. These results suggest that scale and translation invariance is a desirable property.     

Proximal advantage in knowledge diffusion: The time dimension

This paper intends to explore the impact of geographic proximity on the diffusion of knowledge in the form of publication citations, and argues that codified knowledge is transmitted faster in proximity and is subject to similar geographic constraints as tacit knowledge. The geographic proximity advantage would be particularly relevant in the early stage of dissemination. We collected three sets of research articles published in 1990, 2000 and 2010 and compared the longitudinal citations they received domestically and from abroad. The study found that domestic citations accumulate faster and reach their peak much earlier than foreign citations, and the difference is most evident in the first few years after publication. The result shows that geographic proximity does play a role in the speed of knowledge diffusion and points to the network effect for citations. Those located closer to the knowledge origin would be exposed and react to publications faster due to the additional opportunities of research exchange and network.     

饱和链烷烃沸点的拓扑研究

本文从距离矩阵和邻接矩阵出发,结合矩阵的数学知识,提出了一种新的拓扑指数Qx=(W×V)1/8,用最小二乘法拟合b.p.(℃),得到线性回归方程为:b.p.(℃)=-277.814+165.248Qx(r=0.993)     

中国能源外交战略分析与思考

随着能源对于国民经济和国家安全的战略意义不断提升,各国在能源领域所开展的外交活动日益活跃,能源外交在国家总体外交中的地位迅速攀升。因此,大力加强能源外交及对能源外交理论的研究,制定与国家能源发展战略相配套的能源外交战略,在我国具有十分重要的现实意义。符合中国国情的能源外交战略,应该有其明确的内涵与定位,能够把握现存的问题并给以解决问题的出路筹谋。     

初中物理教科书中的能量概念比较研究

当前,在世界范围内,能量概念在科学教育尤其是物理教育中占据着越来越重要的地位。然而,能量概念的特殊性决定了能量概念教学的多样性和复杂性。关于能量概念的教学,我国的中学物理课程与国外的许多教程有较大差异。比较国内外物理教科书中关于能量概念的呈现方式和教学方式的差异,对改进能量概念在教科书中的呈现方式进而帮助学生进一步理解能量的概念具有一定意义。     

Esports players,got muscle? Competitive video game players’ physical activity,body fat,bone mineral content,and muscle mass in comparison to matched controls

BackgroundEsports players, like traditional athletes, practice for long hours and, thus, are vulnerable to the negative health effects of prolonged sitting. There is a lack of research on the physical activity and the health ramifications of prolonged sitting by competitive players. The purpose of this study was to investigate activity levels, body mass index (BMI), and body composition in collegiate esports players as compared to age-matched controls.MethodsTwenty-four male collegiate esports players and non-esports players between 18 and 25 years of age signed a written consent to participate. Physical activity was examined using daily activity (step count) with a wrist-worn activity tracker. A questionnaire assessing physical activity was also administered. Secondary outcomes included body-fat percentage, lean-body mass, BMI, and bone mineral content measured using dual X-ray absorptiometry.ResultsThe step count in the esports players was significantly lower than the age-matched controls (6040.2 ± 3028.6 vs. 12843.8 ± 5661.1; p = 0.004). Esports players exhibited greater body-fat percentage (p = 0.05), less lean body mass (p = 0.003), and less bone mineral content (p = 0.03), despite no difference in BMI between the esports and non-esports players.ConclusionAs compared to non-esports players, collegiate esports players were significantly less active and had a higher body-fat percentage, with lower lean body mass and bone mineral content. The BMIs showed no difference between the 2 groups. Esports athletes displayed significantly less activity and poor body composition, which are all correlated with potential health issues and risk of injury. BMI did not capture this difference and should not be considered as an accurate measure of health in competitive esports players.     

武汉市经济社会发展多目标预警体系研究

研究了武汉市经济社会发展预警系统的基本理论,设计出武汉市经济社会发展的预警系统结构,建立了预警指标体系和预警模型,应用层次分析法和系统模糊决策法,通过专家调查分析,得到了各指标的重要性权数,为武汉市经济社会发展预警管理提供了科学的方法。     

发挥图书馆作用 构建和谐高校

构建和谐高校是社会发展的必然要求,是建设社会主义和谐社会的重要组成部分。高校是文化知识的传播源,和谐高校对社会的和谐具有很大的辐射作用。提出了以人为本加强高校图书馆战略建设,注重图书馆人员的继续教育与培训,全面系统地培养高技能、高层次的专业人才,达到图书馆人际关系和谐,实现全社会和谐之目的。     

中国科学院学部学科发展战略研究的学术影响及其作用

基础研究是原始创新的源泉,加强基础研究,前瞻未来科学发展方向,抢占未来发展的制高点,是新时代国家对中国科学院学部发挥学术引领作用的新要求。中国科学院学部学科发展战略研究工作旨在探索各学科内在发展规律,前瞻各学科中长期发展趋势,把握新兴和交叉学科发展方向,明确科学前沿和重大科学问题,指导我国相关学科发展。文章介绍了中国科学院学部学科发展战略研究工作的基本情况,并通过文献调研和问卷调查分析了学科发展战略研究工作的实施效果与影响。研究表明,中国科学院学部学科发展战略研究工作产生了较好的社会影响、政策影响和学术影响,在夯实我国学科基础、优化科技布局、促进人才培养、增进学术交流、推动科技创新和建设创新型国家等方面均作出了积极贡献。