A heuristic for the time constrained asymmetric linear sum assignment problem

The linear sum assignment problem is a fundamental combinatorial optimisation problem and can be broadly defined as: given an \(n \times m, m \ge n\) benefit matrix \(B = (b_{ij})\), matching each row to a different column so that the sum of entries at the row-column intersections is maximised. This paper describes the application of a new fast heuristic algorithm, Asymmetric Greedy Search, to the asymmetric version (\(n \ne m\)) of the linear sum assignment problem. Extensive computational experiments, using a range of model graphs demonstrate the effectiveness of the algorithm. The heuristic was also incorporated within an algorithm for the non-sequential protein structure matching problem where non-sequential alignment between two proteins, normally of different numbers of amino acids, needs to be maximised.     

Total completion time minimization in online hierarchical scheduling of unit-size jobs

This paper investigates an online hierarchical scheduling problem on m parallel identical machines. Our goal is to minimize the total completion time of all jobs. Each job has a unit processing time and a hierarchy. The job with a lower hierarchy can only be processed on the first machine and the job with a higher hierarchy can be processed on any one of m machines. We first show that the lower bound of this problem is at least \(1+\min \{\frac{1}{m}, \max \{\frac{2}{\lceil x\rceil +\frac{x}{\lceil x\rceil }+3}, \frac{2}{\lfloor x\rfloor +\frac{x}{\lfloor x\rfloor }+3}\}\), where \(x=\sqrt{2m+4}\). We then present a greedy algorithm with tight competitive ratio of \(1+\frac{2(m-1)}{m(\sqrt{4m-3}+1)}\). The competitive ratio is obtained in a way of analyzing the structure of the instance in the worst case, which is different from the most common method of competitive analysis. In particular, when \(m=2\), we propose an optimal online algorithm with competitive ratio of \(16\) \(/\) \(13\), which complements the previous result which provided an asymptotically optimal algorithm with competitive ratio of 1.1573 for the case where the number of jobs n is infinite, i.e., \(n\rightarrow \infty \).     

改进粒子群算法优化灰色神经网络预测模型及其应用

文章针对神经网络存在局部最优、收敛速度慢以及大样本等缺点,将改进的粒子群算法、灰色模型和神经网络模型有机结合,构建了改进粒子群优化灰色神经网络预测模型(IPSO-GMNN).并与其他预测模型进行比较,实证结果表明:IPSO-GMNN预测模型能够克服神经网络预测模型的不足,更好地识别时间序列的非线性和突变性特征.在对我国专利授权数量的预测应用中,新模型对非线性时间数据预测表现出更好的预测精度和稳定性.     

大数据背景下线上商品价格变动对CPI的影响

文章利用2011年2月至2015年9月阿里巴巴研究院公布的网络零售价格(ASPI)指数及其各分类商品价格指数与国家统计局公布的CPI历史数据分别作为线上、线下一般商品价格变动的代理变量,在协整检验的基础上采用向量误差修正模型对线上、线下商品价格变动的关联关系进行了定量分析,并对构成ASPI的各分项商品价格指数与CPI之间的关系进行了分析.研究表明:在误差修正机制的作用下,线上、线下商品价格之间存在稳定均衡的关系.     

Robust inference for group sequential trials

For ethical reasons, group sequential trials were introduced to allow trials to stop early in the event of extreme results. Endpoints in such trials are usually mortality or irreversible morbidity. For a given endpoint, the norm is to use a single test statistic and to use that same statistic for each analysis. This approach is risky because the test statistic has to be specified before the study is unblinded, and there is loss in power if the assumptions that ensure optimality for each analysis are not met. To minimize the risk of moderate to substantial loss in power due to a suboptimal choice of a statistic, a robust method was developed for nonsequential trials. The concept is analogous to diversification of financial investments to minimize risk. The method is based on combining P values from multiple test statistics for formal inference while controlling the type I error rate at its designated value.This article evaluates the performance of 2 P value combining methods for group sequential trials. The emphasis is on time to event trials although results from less complex trials are also included. The gain or loss in power with the combination method relative to a single statistic is asymmetric in its favor. Depending on the power of each individual test, the combination method can give more power than any single test or give power that is closer to the test with the most power. The versatility of the method is that it can combine P values from different test statistics for analysis at different times. The robustness of results suggests that inference from group sequential trials can be strengthened with the use of combined tests.     

国际社会打击索马里海盗的法律分析

为维护国际海运安全,国际社会纷纷派出军舰赴索马里海域参加打击海盗的行动。这一行动的国际法依据是联合国安理会的授权、海洋法公约的相关规定和索马里过渡政府的同意,且三个因素相互关联。同时打击海盗的行动应受到相关国际法的约束,包括履行尊重沿岸国主权的义务、遵守人道主义法则的义务和因国际不法行为造成损失的赔偿责任。     

中国国际经济关系研究的一般特征和发展趋势（之二）：学者、研究机构、地区的学术影响力及研究热点——基于2000-2007年CSSCI期刊论文数据的分析

本文研究了中国国际经济关系研究领域中的学者、研究机构和地区的学术影响力,并分析了该领域的研究热点和研究趋势.本文认为我国国际经济关系研究仍然处于初步成长之中,研究队伍有待进一步培养和扩大,但是研究成果和学术影响力已有显著的提高,高校和社科院系统是研究的主力,北京是研究的中心.     

我国网络新闻传播专业教育现状的思考

本文从当前我国网络新闻传播专业教育的现状入手,论析现阶段我国网络新闻传播专业教育的相关问题。     

西部民族地区社会资本与生态文明建设

从西部民族地区生态文明建设所面临的困难与障碍出发,利用社会资本分析范式,从西部民族地区社会资本对变革生产方式的推动作用、对降低政府管理成本的作用、对提升生态意识的作用等几方面来分析社会资本对推动西部民族地区生态文明建设的积极意义：     

保险代位求偿权行使的相关限制

保险代位求偿权是保险法中的一项专门制度,具有自身独特的地位、特征与功能,在保险实务中的行使很普遍,但保险代位求偿权在行使上有相应的限制。由此,就保险代位求偿权在适用范围、第三人、时效等方面的行使限制情形作探讨分析。