Approximation strategy-proof mechanisms for obnoxious facility location on a line

In the facility location game on a line, there are some agents who have fixed locations on the line where an obnoxious facility will be placed. The objective is to maximize the social welfare, e.g., the sum of distances from the facility to all agents. On collecting location information, agents may misreport the locations so as to stay far away from the obnoxious facility. In this paper, strategy-proof mechanisms are designed and the approximation ratio is used to measure the performances of the strategy-proof mechanisms. Two objective functions, maximizing the sum of squares of distances (maxSOS) and maximizing the sum of distances (maxSum), have been considered. For maxSOS, a randomized 5/3-approximated strategy-proof mechanism is proposed, and the lower bound of the approximation ratio is proved to be at least 1.042. For maxSum, the lower bound of the approximation ratio of the randomized strategy-proof mechanism is proved to be 1.077. Moreover, a general model is considered that each agent may have multiple locations on the line. For the objective functions maxSum and maxSOS, both deterministic and randomized strategy-proof mechanisms are investigated, and the deterministic mechanisms are shown to be best possible.     

Asymptotically optimal policy for stochastic job shop scheduling problem to minimize makespan

This paper studies the large-scale stochastic job shop scheduling problem with general number of similar jobs, where the processing times of the same step are independently drawn from a known probability distribution, and the objective is to minimize the makespan. For the stochastic problem, we introduce the fluid relaxation of its deterministic counterpart, and define a fluid schedule for the fluid relaxation. By tracking the fluid schedule, a policy is proposed for the stochastic job shop scheduling problem. The expected value of the gap between the solution produced by the policy and the optimal solution is proved to be O(1), which indicates the policy is asymptotically optimal in expectation.     

Co-Occurring Psychosocial Problems and Multiple Sexual Partners among Men Who Have Sex with Men in Shanghai,China: A Syndemic Approach

We aimed to apply syndemic theory to verify the association and reinforcing effects between psychosocial problems and multiple sexual partners (MSP) of men who have sex with men (MSM) in Shanghai, China. A cross-sectional study was conducted among 547 MSM in Shanghai, China using a face-to-face survey. Sociodemographic and psychosocial data were collected, as well as information on MSP and condomless anal sex. In the 6 months prior to the survey, 54.3% of the MSM sample had had MSP. Univariate analysis showed that self-esteem, depression, loneliness, sexual compulsivity, and involuntary subordination (IS) were associated with MSP. Sexual compulsivity (multivariate odds ratio [ORm] = 2.94, 95% CI = 1.76–4.91) and IS (ORm = 1.79, 95% CI = 1.14–2.81) remained significant in multivariate analysis. MSM with five or more psychosocial problems had greater odds of (adjusted odds ratios = 3.06, 95% CI = 1.49–6.25) having MSP in the previous 6 months than the non-syndemic group. Our findings provide preliminary confirmation of the additive relationship of syndemic psychosocial health conditions and MSP among MSM in Shanghai, China. An integrated intervention with special focus on sexual compulsivity and IS is needed.     

中国:问题、经验与理论

从学界过去突出"中国问题",到近年来人们越来越多地谈到"中国经验"与"中国理论",表明中国不仅为自己开辟出有特色的现代化道路,也开始在思想理论上向世界发挥积极的影响.而弄清"中国经验"、"中国理论"与西方的"经验"、"理论"的关系,与中国传统的"学问"、"学术"的关系,以及与我们处身其中的现实世界的关系,是我们恰如其分地评估并自觉地开展经验创造和理论建构的前提.本文认为.如果我们过去主要是从"中西古今"的框架看待这些问题的话,那么,现在则应当转向"全球化与地方性"关系的框架.中国的经验与理论能够在多大程度上影响世界,我们在世界上能够获得多大的话语权,取决于我们"地方性"的经验、知识与理论能够在多大程度上成为"全球性"的经验、知识与理论.     

学术期刊的使命与魅力

一本优秀的学术期刊,必须提高核心竞争力,而核心竞争力的重中之重是理论创新,思想性、时代性、规律性与创造性是理论创新的标志;必须突出问题意识,善于提出有意义、有价值的真问题,坚决拒绝无意义、无价值的伪问题;必须直面和回答重大的现实问题,科学地观察"挑战一应战"的社会状态,揭示时代发展中的瓶颈因素,深刻反映人类应对挑战的智慧及成果;必须肩负学术研究导向的使命,在学术水准、学术课题、学术服务、学术争鸣、学术风气等方面发挥导向作用;必须推出新人、扶持新人,为他们提供平台,使他们能够尽快成长起来;必须关注学术的大众化,让一流的学术走进百姓的视野,成为经世致用的显学.学术期刊的魅力正在于此.     

社会空间的拓展:新一轮政府机构改革透视

新一轮地方政府机构改革已拉开帷幕,此次改革的首要任务是转变政府职能,对社会管理体制进行实质性变革.从国家与社会的关系角度来看,国家社会化是此次改革的内在逻辑.从现实背景来看,民间组织的大量涌现以及在社会管理中发挥的重大作用是促进改革的重要力量.从主要趋向来看,经过此次改革,社会力量将从边缘走上前台,社会治理将从控制走向共治,市民社会将由弱小走向成熟.总之,国家与社会将朝着一种全新的关系模式发展.     

金融危机与凯恩斯主义的全面回归——兼论对中国的政策启示

从上个世纪六、七十年代开始,笃信自由放任政策的新古典经济学在西方学术界及政府宏观经济政策层面开始发挥越来越重要的影响,这一时期西方发达国家经济的发展历程似乎也印证了"管得越少的政府越是好政府",市场也越有效率.上个世纪末,世界经济的运行方式发生了很大改变,虚拟经济在西方发达国家呈现高度膨胀的态势,而实体经济则相对萎缩,并且二者的比例严重失调,面对这一新形势,各国政府普遍加强了对经济的介入力度,凯恩斯主义重新回到了历史的前台.这一发展趋势对中国有重要的启示意义.     

科学确证的研究进路探微

现代科学哲学对证据给予假说一定程度支持的考察与研究,经历了由确定性证实到弱证实性确证、由定性分析到定量分析、由二元确证关系考察到三元确证关系考察、由逻辑重构到逻辑与经验统一分析的过程.这一过程既反映出人们对科学确证认识的进步,也体现出对科学确证进行逻辑重构的理性诉求.     

爱因斯坦、量子力学与道家

爱因斯坦与量子力学之间争论的实质是两种科学观的较量,而科学家至今无法对二者进行盖棺论定则源于人们对科学本质属性的困惑。科学是西方主客二元对立思想的产物,科学的发展又进一步巩固了这种对立。在这种思维模式下,很难对两种不同的科学观念进行公平审判。现代科学观遭遇的困境表明,未来的科学观必须超越传统主客对立的僵化思想。只有如此,科学理论才能达到真正的统一。在这一问题上,中国古代道家思想可以为今人提供启示。     

全球一体化、后殖民批判主义和我们的对策

《共产党宣言》发表至今已经160多年,全球一体化虽然与马克思时代有了很大的不同,但马克思关于全球一体化的本质、动力、过程、前景的分析方法以及基本观点,依旧具有指导意义。在全球一体化的过程中,受害最深的仍然是落后国家。落后国家人民反抗西方资本主义经济、文化冲击和压迫的斗争在殖民时代结束后一直没有停止过,后殖民批判主义就是这种文化抗争的形式之一。我们要反对西方的文化帝国主义行径,这与后殖民批判主义的主张基本一致。在全球化趋势的今天,正确对待后殖民批判主义所坚持的立场和观点,冷静分析我国现代化建设中的问题,有必要提出我们应对全球化发展的对策。