基于动态网络分析的中国高绩效科研合作网络共性特征研究

运用动态网络分析法,以CNKI(China National Knowledge Infrastructure)中2017年综合指数排名前五的学者为核心构建的科研合作网络为研究对象,以2006—2017年间学者们参与的国内期刊论文为数据样本,构建含期刊论文影响因子权重的合著网络和关键词网络,从网络总体结构、整体属性和个体属性三个层面系统揭示不同领域高绩效科研合作网络潜在的共性特征,并按照时间段划分探究其演化规律。研究结果表明,高绩效科研合作网络具有整体规模大、平均聚类系数高、平均路径长度小、研究人员与关键词流动数目大等特点。以上研究结果可映射出实际的科研合作网络所具备的特征,对揭示高绩效科研合作网络隐含的共性特征具有理论意义,可为人事管理部门和科研人员对于协同创新战略规划、组织引导机制、管理制度创新等措施的出台提供科学依据。     

Bid keyword suggestion in sponsored search based on competitiveness and relevance

In sponsored search, many advertisers have not achieved their expected performances while the search engine also has a large room to improve their revenue. Specifically, due to the improper keyword bidding, many advertisers cannot survive the competitive ad auctions to get their desired ad impressions; meanwhile, a significant portion of search queries have no ads displayed in their search result pages, even if many of them have commercial values. We propose recommending a group of relevant yet less-competitive keywords to an advertiser. Hence, the advertiser can get the chance to win some (originally empty) ad slots and accumulate a number of impressions. At the same time, the revenue of the search engine can also be boosted since many empty ad shots are filled. Mathematically, we model the problem as a mixed integer programming problem, which maximizes the advertiser revenue and the relevance of the recommended keywords, while minimizing the keyword competitiveness, subject to the bid and budget constraints. By solving the problem, we can offer an optimal group of keywords and their optimal bid prices to an advertiser. Simulation results have shown the proposed method is highly effective in increasing ad impressions, expected clicks, advertiser revenue, and search engine revenue.     

作者合著网络中研究兴趣相似性实证研究

[目的/意义]从作者微观个体研究兴趣角度出发,通过对作者合著网络中作者关联关键词集的研究,定量地验证研究兴趣相似是作者合作的一个动机。[方法/过程]收集WOS中检索领域相关文献题录信息,构建作者合著网络,并利用Louvain算法划分社区,实现了Jaccard系数及余弦相似性系数的计算指标,统计与对比分析整体网络及社区内部作者研究兴趣的相似性。[结果/结论]在网络整体层次,作者合著网络中作者的研究兴趣相似性较高,但也存在一定比例的差异性即互补性;在科研社区内部,合著作者平均研究兴趣相似性及互补性均高于网络整体层次,科研社区的形成受到作者研究兴趣的影响。两个层次的兴趣相似性反映了研究兴趣相似是作者合作的一个重要动机。     

Connections between online harassment and offline violence among youth in Central Thailand

Increasing evidence indicates that face-to-face (offline) youth violence and online harassment are closely interlinked, but evidence from Asian countries remains limited. This study was conducted to quantitatively assess the associations between offline violence and online harassment among youth in Central Thailand. Students and out-of-school youth (n = 1,234, age: 15–24 years) residing, studying, and/or working in a district in Central Thailand were surveyed. Participants were asked about their involvement in online harassment and in verbal, physical, sexual, and domestic types of offline violence, as perpetrators, victims, and witnesses within a 1-year period. Multivariable logistic regression was used to assess independent associations between different kinds of involvement in offline violence and online harassment. Perpetration and victimization within the past year were both reported by roughly half of the youth both online and offline. Over three quarters had witnessed violence or harassment. Perpetrating online harassment was independently associated with being a victim online (adjusted odds ratio [AOR] = 10.1; 95% CI [7.5, 13.6]), and perpetrating offline violence was independently associated with being a victim offline (AOR = 11.1; 95% CI [8.1, 15.0]). Perpetrating online harassment was independently associated with perpetrating offline violence (AOR = 2.7; 95% CI [1.9, 3.8]), and being a victim online was likewise independently associated with being a victim offline (AOR = 2.6; 95% CI [1.9, 3.6]). Online harassment and offline violence are interlinked among Thai youth, as in other countries studied so far. Interventions to reduce either might best address both together.     

LDA单词图像表示的蒙古文古籍图像关键词检索方法

[目的]为了克服传统视觉词袋方法（Bag-of-Visual-Words）中忽略视觉单词间的空间关系和语义信息等问题。[方法]本文提出一种与视觉语言模型相结合的基于LDA主题模型,并采用查询似然模型实现检索。[结果]实验数据表明,本文所提出的基于LDA的表示方法可以高效、准确地解决蒙古文古籍的关键词检索问题。[结论]同时,该方法的性能比BoVW方法有显著提高。