Split Hamiltonian Monte Carlo

We show how the Hamiltonian Monte Carlo algorithm can sometimes be speeded up by “splitting” the Hamiltonian in a way that allows much of the movement around the state space to be done at low computational cost. One context where this is possible is when the log density of the distribution of interest (the potential energy function) can be written as the log of a Gaussian density, which is a quadratic function, plus a slowly-varying function. Hamiltonian dynamics for quadratic energy functions can be analytically solved. With the splitting technique, only the slowly-varying part of the energy needs to be handled numerically, and this can be done with a larger stepsize (and hence fewer steps) than would be necessary with a direct simulation of the dynamics. Another context where splitting helps is when the most important terms of the potential energy function and its gradient can be evaluated quickly, with only a slowly-varying part requiring costly computations. With splitting, the quick portion can be handled with a small stepsize, while the costly portion uses a larger stepsize. We show that both of these splitting approaches can reduce the computational cost of sampling from the posterior distribution for a logistic regression model, using either a Gaussian approximation centered on the posterior mode, or a Hamiltonian split into a term that depends on only a small number of critical cases, and another term that involves the larger number of cases whose influence on the posterior distribution is small.     

学前教育事业发展的公平之维——罗尔斯正义论的视角

学前教育公平是学前教育事业发展的首要价值。由于学前期幼儿身心发展的迅速且不可逆性，一旦错失发展机遇以后不容易补偿，因此学前教育公平对一个人终生的发展具有极端重要性。按照罗尔斯正义论的看法，学前教育事业发展应该首先向弱势群体倾斜，保障处境不利幼儿平等的受教育权。     

A Factor-Adjusted Multiple Testing Procedure With Application to Mutual Fund Selection

In this article, we propose a factor-adjusted multiple testing (FAT) procedure based on factor-adjusted p-values in a linear factor model involving some observable and unobservable factors, for the purpose of selecting skilled funds in empirical finance. The factor-adjusted p-values were obtained after extracting the latent common factors by the principal component method. Under some mild conditions, the false discovery proportion can be consistently estimated even if the idiosyncratic errors are allowed to be weakly correlated across units. Furthermore, by appropriately setting a sequence of threshold values approaching zero, the proposed FAT procedure enjoys model selection consistency. Extensive simulation studies and a real data analysis for selecting skilled funds in the U.S. financial market are presented to illustrate the practical utility of the proposed method. Supplementary materials for this article are available online.     

人工智能时代的话语悖论与结构转向

以追求智能、精准为核心的技术认知对突发社会问题的预测失灵,形塑了人工智能时代的话语悖论。此悖论体现出盲目崇尚加速的、闭合化的现代性认知结构的困窘,且揭示了晚近技术反思的谱系化与经验"二分"的双重结构观的局限性,进而使超越悖论的结构转向成为必须面对的命题。因此关键在于以突发社会问题为节点,面向日常生活,实现对"二分"的总体性统合。唯有把握日常生活在突发问题中可能产生的反转契机,合理审视智能化的技术,促使技术的精准思维融入于日常生活之中,方能为加速多变的现代科学创设总体化的良善格局。     

Fibonacci helps to evacuate from a convex region in a grid network

This study considers an evacuation problem where the evacuees try to escape to the boundary of an affected area, which is convex, and a grid network is embedded in the area. The boundary is unknown to the evacuees and we propose an online evacuation strategy based on the Fibonacci sequence. This strategy is proved to have a competitive ratio of 19.5, which is better than the best previously reported result of 21.     

基于商业化趋势下的湖南舞蹈产业发展研究

尽管湖南的舞蹈产业正在有条不紊的发展着,但事实上其发展过程中已经显现了一定的疲态。通过对商业化趋势下的舞蹈产业发展进行综合分析,尝试进行基于传统舞蹈、群众舞蹈等方面的商业化探索,同时强调推广平台的重要性,旨在寻求舞蹈艺术与商业价值之间的平衡,从而实现舞蹈产业在商业化道路上的良性发展。     

“可行能力”与西部民族地区和谐社会构建

“可行能力”是一个有重要理论意义的经济学范畴。一个人的可行能力指的是此人有可能实现的、各种可能的功能性活动的组合。可行能力是实现各种可能的功能性活动组合的实质自由（或者用日常语官说，就是实现各种不同生活方式的自由）。缺乏“可行能力”，难以构建西部民族地区和谐社会。西部民族地区的个人可行能力归纳为三个方面，即利益表达、经济参与和社会机会，以此来考察西部民族地区的个人可行能力的状况。     

我国上市公司信息披露机制实证检验——基于投资者保护的视角

基于投资者保护的上市公司信息披露机制的实证检验表明,公司的信息质量以及信息披露的及时性能够发挥投资者的保护功能;仅通过提高公司信息披露的频率还远远不够,关键是提高公司信息披露质量;公允价值计量基础没有成为投资者保护的有效促进因素,反而可能成为公司进行盈余管理的手段.对此,应加强我国证券市场的信息监管,制定高质量的会计准则,实现上市公司信息披露制度由静态监管向动态监管的转变.     

油气田边远地区天然气资源的综合利用研究

油气田边远地区天然气资源包括油田放空天然气(主要是油田伴生气)和低产气井天然气,它们均因气量小,就地无用户和远离输气管网等原因长期未得到开发利用,不仅极大地浪费了资源,而且严重地污染了油田地区的大气。综述了国内外可用于油气田边远地区天然气资源开发利用的净化技术和综合利用技术,认为利用这部分天然气资源应依据气质、气量和市场需求选用合理的净化技术及利用技术,最后对吐哈油田边远地区天然气资源的综合利用进行了研究。     

谈弗·雷·利维斯小说批评中的非个性化原则

非个性化是利维斯衡量其伟大小说和小说家的重要尺度.通过时这一尺度的诠释来捕捉和说明利维斯评价标准的实质,推敲和体味这一标准在其重要评价中所具有的丰富意蕴,这对于我们正确理解和评价利维斯的批评事业无疑是至关重要的.