Investigating and counteracting popularity bias in group recommendations

Popularity bias is an undesirable phenomenon associated with recommendation algorithms where popular items tend to be suggested over long-tail ones, even if the latter would be of reasonable interest for individuals. Such intrinsic tendencies of the recommenders may lead to producing ranked lists, in which items are not equally covered along the popularity tail. Although some recent studies aim to detect such biases of traditional algorithms and treat their effects on recommendations, the concept of popularity bias remains elusive for group recommender systems. Therefore, in this study, we focus on investigating popularity bias from the view of group recommender systems, which aggregate individual preferences to achieve recommendations for groups of users. We analyze various state-of-the-art aggregation techniques utilized in group recommender systems regarding their bias towards popular items. To counteract possible popularity issues in group recommendations, we adapt a traditional re-ranking approach that weighs items inversely proportional to their popularity within a group. Also, we propose a novel popularity bias mitigation procedure that re-ranks items by incorporating their popularity level and estimated group ratings in two distinct strategies. The first one aims to penalize popular items during the aggregation process highly and avoids bias better, while the second one puts more emphasis on group ratings than popularity and achieves a more balanced performance regarding conflicting goals of mitigating bias and boosting accuracy. Experiments performed on four real-world benchmark datasets demonstrate that both strategies are more efficient than the adapted approach, and empowering aggregation techniques with one of these strategies significantly decreases their bias towards popular items while maintaining reasonable ranking accuracy.     

上海“朱葆三路”考——以地方志为中心

通过翻检新修地方志，考证得出位于近代上海法租界内的朱葆三路曾经历过命名——改名——复名——再改名等阶段，首度命名始于1922年，中止时间为1943年10月9日。大约从抗战胜利初期至20世纪50年代又被复名使用，总计使用时间30年左右。     

Toward a Communication Model for the Socialization of Voluntary Members

Because most socialization/assimilation research focuses on employment as the primary membership role in groups and organizations, the accompanying models have failed to consider the unique characteristics of voluntary membership. In addition, those models have been criticized for being too linear and based on concepts of organizations as containers. Using principles of the bona fide group perspective and a case study, this paper develops a model that emphasizes the unique characteristics of the socialization of voluntary members. The multilevel model also examines how membership in various other groups, such as work and family, influence and interact with individuals’ voluntary memberships. With a focus on communication, the model emphasizes the fluid process of voluntary associations in organizations with ambiguous boundaries.     

Parliamentary procedure in a community group: Communication and vigilant decision making

Parliamentary procedure is pervasive in most decision‐making groups of a dozen or more persons, but it is has been understudied as an important influence on the group communication process. It is not well understood by members of groups who claim to have adopted it, and procedures are seldom invoked in ways that suggest a very sophisticated model. However, parliamentary procedure need not be considered as simply a rigid set of laws. This multi‐phase research project provides insight into how parliamentary procedure is selectively used in community groups and functions as a set of rules that influences the vigilance of the communication process.     

Classroom communication satisfaction,teacher uncertainty and course certainty over time 1

Classroom communication satisfaction (CCS), teacher uncertainty and course certainty were examined over time. Results indicated a decrease in teacher uncertainty while CCS and course certainty did not significantly change over time. Discussion focused on an interpretation of the results.     

开滦集团组织人事管理机制的优化策略

立足开滦集团实际：分析了组织人事管理面临的三个新挑战，提出了优化组织人事管理机制的思路及构建战略组织人事管理模式的措施。     

大生集团早期金融事业的兴衰

近现代中国最大工业集团之一大生集团主要是通过借贷融资、发行股票和建立银行吸储等将民间资金及少量官款转化为工业资本。1920年,大生系工商资本集团创建了淮海实业银行和花纱与股票交易所。银行还印备了钞票,准备占领更大分额的资本市场。但大生集团未能象日本涩泽系企业集团那样在较早的时候就建设好工商活动与金融事业间的良性关系。连同交易所在内的大生系的金融机构在数年后未能承受苏北大水灾等所引发的金融危机。大生集团早期金融业的兴衰为当代中国民营企业的资本积累和运作,提供了值得记取的经验和教训。     

Anonymity in classroom voting and debating

The advent of networked environments into the classroom is changing classroom debates in many ways. This article addresses one key attribute of these environments, namely anonymity, to explore its consequences for co-present adolescents anonymous, by virtue of the computer system, to peers not to teachers. Three studies with 16-17 year-olds used a vote-debate-vote scenario to explore in Study 1 (N = 59) anonymous, public or private voting with public oral debate; Study 2 (N = 79) anonymous, public or private voting with public written debate; and Study 3 (N = 84) anonymous or public voting and debating. Students were more likely to change their views after debate and show less convergence to group norms if voting anonymously. However, anonymous debate created an increased amount of off-task behaviour, but only at the beginning of the lesson. In general, anonymity was found to bring positive benefits to classroom argumentation.     

《楚辞·天问》所见夷夏关系及其考古学印证

《天问》中保存了较多的夏、夷集团的史料,全面地反映了五帝时代中期至夏初两大集团的关系是权力斗争和交流并进的：在夷夏斗争中,包含着婚姻等和平方式的交往;在婚姻关系中,也蕴含着斗争和利用,并非以往学者所说的单纯的武力斗争。《天问》仅千字之文,全面记载了这一时期东夷、华夏集团联盟间的重要史事,难能可贵。