Simplicial Pivoting Algorithms for a Tractable Class of Integer Programs

We present a tractable class of integer feasibility problems. This class of max-closed IP problems was studied in somewhat restricted form by Glover, Pnueli, Hochbaum and Chandrasekaran and has a logic counterpart known as the class of Horn formulas. First we modify the existing algorithms in order to avoid the related recognition problem. Then we show that in order to solve these max-closed IP problems, simplicial path following methods can be used. This is important because these methods are flexible with respect to starting conditions, which make them more suitable than the top-down truncation algorithms that have been suggested.     

贸易与环境实证研究综述

在过去10年中,贸易与环境问题越来越成为学术界和大众关注的热点。贸易与环境问题的复杂性和可靠数据的缺乏限制了贸易与环境的实证研究。该文首先综述了贸易与环境实证研究的背景、主要方向和进展;然后总结了研究的主要方法和观点;最后简要表明作者的观点。该文围绕两个问题进行：①环境政策对国内产业和贸易的影响;②贸易与环境的联系, 贸易政策对环境的影响。     

水资源社区自主管理的历史考察——以明清晋陕地区为例

面对严峻的水资源短缺和明清地方政府在水资源管理事务中的强力收缩,晋陕地区水资源呈现出社区自主管理的特点。以乡绅阶层为核心力量的民间水利组织,逐渐承担起水资源管理的任务。他们依靠一系列建立在用水惯例、传统伦理道德和国家水法基础上的水利规约,形成了和谐的用水秩序,保障了社区整体的用水安全,其管理成效具体体现在小型水利工程的兴修、水利纠纷的妥善处理等方面。但是,受监督体制的缺失和狭隘的局部用水观念的影响,作为领导核心力量的乡绅阶层在水管理过程中也不可避免地出现了腐败、渎职等问题,同时,农民阶层对水管理参与权的缺失,也使得这种自主管理的民主性是有限度的。     

郭象美学的本体论

作为魏晋玄学发展成熟阶段的代表人物,郭象吸取了诸家的思想资源,开辟出了一条关于人性的精神本源的思路.由于论证的艰难性,郭象不得不借助牢笼中的语言来摆脱语言的牢笼,通过对造物生成论、自生论的不断否定,向我们展开了人性的生存之根"独化"."独化"在最高旨趣上达到人的天性,人在精神上走向无限.     

The unequal impact of Covid-19 on the lives and rights of the children of modern slavery survivors,children in exploitation and children at risk of entering exploitation

This article discusses the unequal impact of Covid-19 on the lives of the children of survivors of modern slavery, child victims of exploitation and children at risk of exploitation in the UK. It draws on research that has analysed the risks and impacts of Covid-19 on victims and survivors of modern slavery. It explores how pandemic responses may have hindered these children's rights to education, food, safety, development and participation and representation in legal processes. It suggests that the pandemic should be used as an impetus to address inequalities that existed pre-Covid-19 and those that have been exacerbated by it.     

Modified genetic algorithm-based clustering for probability density functions

This article modifies two internal validity measures and applies them to evaluate the quality of clustering for probability density functions (pdfs). Based on these measures, we propose a new modified genetic algorithm called GA-CDF to establish the suitable clusters for pdfs. The proposed algorithm is tested by four numerical examples including two synthetic data sets and two real data sets. These examples illustrate the superiority of proposed algorithm over some existing algorithms in evaluating the internal or external validity measures. It demonstrates the feasibility and applicability of the GA-CDF for practical problems in data mining.     

Public Access to Government Information in the Digital Age: Findings from China

The openness of government information is an unavoidable issue in the digital age. The Chinese government makes great effort to publish administrative information and seek advice on good governance from the general public, but is nonetheless unable to meet citizens’ legitimate demands for the right to know and participate. This study analyzes this contradiction from four angles: the driving force, the type of information, the access platform, and the annual examination and supervision system for government information disclosure. The findings showed that (a) netizens’ heavy pressure rather than Chinese authorities’ strong leadership pushes forward the disclosure of government information; (b) administrative information concerning the public agenda rather than the policy agenda best meets the needs of the general public; (c) commercial Weibo websites are a more satisfactory channel than official government websites for practical requests; and (d) as a unique institutional arrangement for examination and supervision, the annual report on government information disclosure should be standardized.     

灰色关联决策方法研究

以灰色决策分析理论为基础,探讨了经典灰色关联决策方法的优势和不足。提出了基于理想方案的最大关联度方法、基于临界方案的最小关联度方法,以及同时考虑理想方案和临界方案的综合关联度方法及其相关概念。建立了灰色区间关联系数公式和灰色区间相对关联系数公式。运用分析技巧,构建了上述3种关联度决策算法。指出了灰色区间关联系数公式和最大关联度方法分别是经典灰色关联系数公式和灰色关联决策方法的推广,而最小关联度方法和综合关联度方法是经典灰色关联决策方法的拓展。文中实例说明了所提出的灰色关联决策方法的合理性及其算法的有效性。     

Nonparametric depth-based multivariate outlier identifiers, and masking robustness properties

In extending univariate outlier detection methods to higher dimension, various issues arise: limited visualization methods, inadequacy of marginal methods, lack of a natural order, limited parametric modeling, and, when using Mahalanobis distance, restriction to ellipsoidal contours. To address and overcome such limitations, we introduce nonparametric multivariate outlier identifiers based on multivariate depth functions, which can generate contours following the shape of the data set. Also, we study masking robustness, that is, robustness against misidentification of outliers as nonoutliers. In particular, we define a masking breakdown point (MBP), adapting to our setting certain ideas of Davies and Gather [1993. The identification of multiple outliers (with discussion). Journal of the American Statistical Association 88, 782–801] and Becker and Gather [1999. The masking breakdown point of multivariate outlier identification rules. Journal of the American Statistical Association 94, 947–955] based on the Mahalanobis distance outlyingness. We then compare four affine invariant outlier detection procedures, based on Mahalanobis distance, halfspace or Tukey depth, projection depth, and “Mahalanobis spatial” depth. For the goal of threshold type outlier detection, it is found that the Mahalanobis distance and projection procedures are distinctly superior in performance, each with very high MBP, while the halfspace approach is quite inferior. When a moderate MBP suffices, the Mahalanobis spatial procedure is competitive in view of its contours not constrained to be elliptical and its computational burden relatively mild. A small sampling experiment yields findings completely in accordance with the theoretical comparisons. While these four depth procedures are relatively comparable for the purpose of robust affine equivariant location estimation, the halfspace depth is not competitive with the others for the quite different goal of robust setting of an outlyingness threshold.