Efficient heterogeneous sampling for stochastic simulation with an illustration in health care applications

In modeling disease transmission, contacts are assumed to have different infection rates. A proper simulation must model the heterogeneity in the transmission rates. In this article, we present a computationally efficient algorithm that can be applied to a population with heterogeneous transmission rates. We conducted a simulation study to show that the algorithm is more efficient than other algorithms for sampling the disease transmission in a subset of the heterogeneous population. We use a valid stochastic model of pandemic influenza to illustrate the algorithm and to estimate the overall infection attack rates of influenza A (H1N1) in a Canadian city.     

竞争中的参考价格效应及承诺

消费者的社会感知会影响其对产品和品牌的评价。当消费者进行购买选择时，经常会受到参考价格效应的影响。而广告和价格不仅是企业经常要考虑的重要决策，还会对参考价格产生重要影响。为此，一个值得研究的的问题是：在考虑参考价格效应的情况下，企业该怎样确定其动态广告和价格策略？
为了研究该问题，本文构建了一个广告和价格的动态模型，来研究一个双寡头市场环境下两个寡头企业的价格和广告决策，并以此分析参考价格效应的作用。具体而言，我们假定企业可以采用广告承诺和价格承诺中的一种，其中前者承诺其在一段时间内的广告投入量恒定不变，而后者确保价格不变。两种策略不仅会影响消费者的购买决策，也会影响竞争对手的选择。在上述假定下，我们探讨了两个寡头企业在都采用广告承诺、都采用价格承诺及一个企业采用广告承诺而另一个企业采用价格承诺等三种不同情形下的最优广告和价格决策，并以此分析了三种情形下参考价格效应对最优的广告投入及定价策略的影响。最后，通过数值分析，探讨了不同情形下企业的最优策略选择。     

Load-Oriented Order Release (LOOR) revisited: bringing it back to the state of the art

In the workload control literature, the Load-Oriented Order Release (LOOR) approach has been neglected since its robustness was questioned at the end of the 1990s. This paper revisits LOOR and evaluates whether its performance can be improved in two ways. First, an intermediate pull release mechanism is added to avoid starvation between periodic release events. This mechanism was recently shown to be effective at improving the performance of a state-of-the-art release method known as LUMS COR. Second, an integer linear programming model is used to manage the trade-off between the timing and load balancing functions of order release. The two refinements are assessed using simulations of different shop configurations, which allow us to evaluate robustness. Results demonstrate that the refinements contribute to improving the performance of LOOR such that it can even outperform LUMS COR. Perhaps counter-intuitively, putting more emphasis on load balancing than on the urgency of individual orders is shown to lead to a lower percentage of tardy orders. Overall, the improvements mean that concerns about LOOR’s robustness are no longer valid – it now appears suitable for a wide range of shops found in practice.     

舆论危机的异化极化效应研究

随着Web2.0时代的到来,网络媒体逐渐成为舆论生成、传播和交锋的主阵地,舆论危机的形成及其异化也成为日益突出的社会风险问题.本文以舆论的异化演化机理为研究对象,通过梳理典型事件舆论话题的异化过程,对其基本内涵、表现形式和演化模式等进行系统总结.随后,研究以舆论超网络模型为基础,借鉴社会影响理论的基本原则,提出舆论异化机理的极化算法,并对其具体流程进行解析和实现.最后,本文以“7·23甬温动车事故”为例,对舆论危机的异化极化过程和影响因素进行系统仿真和实证分析.     

邓小平社会主义核心价值观教育思想探析

以泰州某大跨度连续梁桥的静动载试验为例，建立ANSYS和桥梁博士模型进行静动力有限元数值计算。将试验结果与模型计算值进行比较，试验结果表明,该桥结构刚度和承载能力满足设计要求。     

Flexible work planning of service agents with load balancing

This work emerged from the need to better plan the daily work of 29 travelling service agents, who provide 1090 services to 412 customers in 283 sites, on daily average. A handy and flexible tool was developed and is presented herein. A major contribution of this study is an explicit consideration of the multi-dimensional nature of the problem by the inclusion of workload balancing, which may stand in conflict to cost minimisation. Further, the geographical distribution of the demand is highly irregular. Therefore, two load measures are required and balanced. This required to fitting a proper planning scheme. The planning tool has been applied successfully by the commercial service provider. Improvements in the order of 20% and more were obtained in key performance measures. Moreover, cost reductions, service improvement and load balance were obtained simultaneously: the standard deviations of the service times and working day’s duration were reduced by 18 and 58%, respectively. This enables to reduce the number of agents with no significant harm in performance. Additional practical advantages of the proposed tool are also discussed and demonstrated, for example, the ability to cope with geographical distributions and the flexibility to respond to daily variations in demand.     

适应性市场假说及其在中国资本市场的实证

金融危机近些年爆发频繁,传统市场理论如有效市场假说和行为金融面对复杂的现实金融世界未能给出合理解释.Lo提出的适应性市场假说则弥合了这两个学派的分歧,逐渐引起了学术界的重视.本文尝试从动态市场效率、时变贝塔和技术交易策略演变这三个角度对适应性市场假说能否解释我国资本市场进行实证研究.研究发现:我国股票市场效率在动态变化,无效的时段与金融危机或政策巨变等重大事件联系密切;股市风格指数贝塔随市场环境变化而改变;技术交易策略绩效随投资者适应环境变化而演变.研究结果表明,适应性市场假说相比有效市场假说和经典资本资产定价模型,能够更好地解释我国资本市场上述现象.最后对投资者如何根据市场环境变化制定适应性投资策略给出几点建议.     

Production and changeover control policies of a class of failure prone buffered flow-shops

This article deals with a stochastic optimal control problem for a class of buffered multi-parts flow-shops manufacturing system. The involved machines are subject to random breakdowns and repairs. The flow-shop under consideration is not completely flexible and hence requires setup time and cost in order to switch the production from a part type to another, this changeover is carried on the whole line. Our objective is to find the production plan and the sequence of setups that minimise the cost function, which penalises inventories/backlogs and setups. A continuous dynamic programming formulation of the problem is presented. Then, a numerical scheme is adopted to solve the obtained optimality conditions equations for a two buffered serial machines two parts case. A complete heuristic policy, based on the numerical observations which describe the optimal policies in system states, is developed. It will be shown that the obtained policy is a combination of a KANBAN/CONWIP and a modified hedging corridor policy. Moreover, based on our observations and existent research studies extension to cover more complex flow-shops is henceforth possible. The robustness of such a policy is illustrated through sensitivity analysis.     

试论邓小平关于"发展"与"稳定"的思想

邓小平在综览当代世界政治经济形势,深刻反思近百年来特别是最近几十年来中国社会发展的曲折历程的基础上,提出了独具特色的关于社会"发展"与"稳定"的思想,以及这一思想付诸实现的具体措施."发展"与"稳定"思想具有动态平衡性.     

西南边疆多民族地区社会动力机制

在推进和谐社会建设的进程中，西南边疆多民族地区社会动力机制运行不断完善，但还存在许多问题：社会发展的经济动力不足，政府的工作存在比较大的改进空间，法律法规的规范力处在较低层次上，社会成员的认知程度和文化需求的现实满足程度还偏低。实现西南边疆多民族地区社会和谐必须把推动社会发展的经济动力、政治动力、文化动力等充分激活，让创造社会价值和财富的源泉充分进发。