村支书和村委会主任:村民自治背景下的权力博弈

作为传统的一把手,村支书一直执掌村中决策和管理大权。然而随着村民自治在农村的强力推进,村委会的影响力也在不断提升,村民直选的村主任作为村庄的法定代表,要扮演“当家人”的角色,不可避免地面临着与传统村庄权威村支书的权力再分配问题,即政务村务治理权的力量博弈。实际上,村党支部和村委会关系的协调与否,不仅同各自的权力来源和村支书与村委会主任的个人影响力有直接关系,而且同现实状况关系密切,博弈结果因而呈现多样化。     

Neighborhood Characteristics,Parenting, and Children’s Safety

Recent studies highlight the importance of neighborhood context for child and family well-being. Yet challenges to research on neighborhood effects remain; research on young children is sparse, as is research on neighborhood effects on parenting. Measurement also continues to challenge researchers, particularly in devising non-invasive means of gauging neighborhood characteristics. The present study seeks to address these issues by using data from a newly developed observational measure of neighborhood characteristics to examine parent reports of the safety of neighborhood children in the home and self-reports of parenting. The results showed that neighborhood characteristics accounted for 23% of the variance in parent perceptions of children's safety in the home, with neighborhood physical appearance strongly predicting children's safety. Neighborhood effects on self-reported parenting were more modest, accounting for just 6% of the variance in parents' reports of nurturing interactions with their children; vigilance for the safety of the neighborhood was a significant predictor. The study has implications for observational measurement of neighborhood effects and for policy and program practices to improve child and family well-being through neighborhood change.     

论美国城市的定居救助之家运动

19世纪末至20世纪初期,面对美国城市社会贫困形势的日益恶化和外国移民贫民区在美国大城市中的涌现,一批出身美国本土白人新教徒中产阶级家庭的青年大学毕业生,志愿深入到城市贫民区开办定居救助之家,开展对穷人的帮教活动,并积极进行社会调查,争取社会进步立法,这就是历史上美国城市的定居救助之家运动。该运动的开展不仅直接帮助了一部分穷人走出贫困生活,尤其是帮助了一部分贫穷儿童的成长,而且揭开了美国进步运动的序幕,推动了社会进步。     

人口“就近城镇化”：人口迁移新方向

新一轮的城镇化发展必将成为国家战略。如何重新认知和甄别新时期我国城镇化发展的道路、模式、方向与目标,是一个重要的理论与现实问题。这要求改变原有的＂离土不离乡＂、＂进厂不进城＂的老思路,走一条农民＂离土又离乡,进厂也进城＂的人口就近城镇化的新道路。在政府的城乡统筹战略的带动下,真正实现农民生产生活方式的城市化,并最终从心理上实现市民化的人口结构的根本转变。     

Capital at Home and at School: A Review and Synthesis

Human, financial, and social capital from several contexts affects child and adolescent well‐being. Families and schools are among the most important, and research is increasingly studying how effects of capital across such contexts affect child and adolescent academic and social outcomes. Some research suggests that families may be more powerful than schools in promoting child and adolescent well‐being. Additional research is needed to more fully understand how capital across institutions interacts in producing child well‐being, when and why multiple institutions or levels of analysis are relevant, and how several contexts can form chains of causation. Theories of social capital may promote increased conversation among researchers who study the same outcomes yet focus their analyses on different contexts.     

基于自适应大邻域搜索的鲁棒多项目调度方法

多项目资源管理有时需要采用一种资源专享-转移策略，该策略下可更新资源在多项目之间不共享，但在当前项目完工之后其资源可以转移至其它还未开始的项目。针对这一实际问题的理论研究非常有限。考虑活动工期的不确定性，从时差效用函数视角评价项目调度计划的鲁棒性，在考虑拖期成本-鲁棒性的多目标问题框架下，构建了一个资源专享-转移视角下的多项目资源分配(战术层)与鲁棒调度(运作层)双层决策优化模型。针对模型的NP-hard性质和多目标组合优化特征，设计了一种新的自适应大邻域搜索(adaptive large neighborhood search，ALNS)算法求解模型。该算法采用“项目-缓冲-资源-活动”列表的混合编码表示问题可行解，提出基于四类列表的destroy-repair邻域结构，设计一种超体积指标进行自适应搜索以提高算法性能。最后，为了验证ALNS算法的适用性和有效性，设计一种NSGA-II算法作为比较基准，通过大规模仿真实验对算法性能进行了对比分析，并探索工期不确定水平对多项目调度方案鲁棒性的影响。     

Intergenerational mobility and racial inequality: The case for a more holistic approach

Intergenerational social mobility studies have largely explored the relationship between one aspect of parent background (e.g., education, income, occupational status, wealth, or neighborhood context) and the corresponding aspect of that parent's child once they reach adulthood. Studies examining these various measures have provided differing conclusions about the extent that social origins constrain attainment in the U.S. In contrast, the persistence of racial inequality in intergenerational mobility is one consistent finding. For instance, across various measures, research demonstrates Black individuals are more likely than White individuals to experience downward mobility, and less likely to exceed the socioeconomic standings of their parents. In this article, we argue that a more holistic measure of both origin and destination, one that combines the above-mentioned indicators, is necessary to advance our understanding of the extent that origin constrains future attainment. We summarize lessons gleaned from one-dimensional estimates, and from other approaches that either combine some dimensions of socioeconomic background or attempt to capture a more holistic background in other ways. We then make a recommendation for methodological interventions to accomplish this more holistic approach and conclude with research and policy implications.     

Trajectories of discrimination among Chinese American youth: Variation,predictors, and outcomes

Using 3 waves of longitudinal data from 444 Chinese American adolescents (M_age = 13.04 at Wave 1, 54% identified as women), the current study explored if there was variation in discrimination trajectories from early to late adolescence and whether contextual and individual factors predicted trajectories as well as if trajectories were associated with academic achievement and mental health. Three distinct discrimination trajectories were identified: low-increasing, moderate-stable, and high-decreasing. The results also revealed that neighborhood Chinese concentration and adolescents' acculturation predicted discrimination trajectories. Different trajectories were also associated with depressive symptoms; adolescents in the high-decreasing trajectory reported higher levels of depressive symptoms in late adolescence than in the other two trajectories. The findings highlight the heterogeneity in Chinese American adolescents' discrimination experience.     

无人仓系统储位分配问题的优化模型与算法

考虑到无人仓系统补货阶段货架上只有部分空余储位的特点，研究了补货商品储位分配问题的优化模型与算法。以同一货架上存放的商品之间关联度之和最大化为目标建立了混合整数规划模型；结合贪婪算法和邻域搜索算法设计了求解模型的两阶段方法。第一阶段利用贪婪算法求初始可行解；第二阶段利用邻域搜索算法对初始可行解进行优化。利用一个具体算例验证了邻域搜索算法的优化效果，结果显示，通过邻域搜索算法对初始可行解的优化，可以使目标函数值至少提升27%。进一步利用多个小规模算例分析了两阶段算法的近似比和求解速度，验证了算法的快速有效性。本文的研究结果不仅解决了货架初始状态非空情况下的储位分配问题，同样适合解决货架初始状态为空的情况，因此更加符合实际场景，可以作为无人仓管理信息系统的核心模型和算法。