2004年武汉市公共场所室内空气微生物检测结果分析

为了研究公共场所空气微生物污染水平,对武汉市36家公共场所采用空气平皿沉降法进行微生物污染水平调查;其中宾馆饭店7家,大型商场超市15家,娱乐健身等场所14家,共检测空气样品2 040件.结果显示:武汉市宾馆饭店(合格标准为≤10 CFU/皿)空气细菌总数全年不合格率为25%,大型商场超市(合格标准为≤75 CFU/皿)空气细菌数全年不合格率为0%,娱乐健身等场所(合格标准为≤40 CFU/皿)空气细菌数全年不合格率为0%.结果表明武汉市多数公共场所室内空气卫生质量良好,少数饭店受微生物污染较重.     

A fuzzy clustering approach to real-time demand-responsive bus dispatching control

Quick response (QR) to passenger needs is a key objective for advanced public transportation systems (APTS), and it has become increasingly important for contemporary metropolitan bus operations to gain a competitive advantage over private transportation. This paper presents a real-time control methodology for demand-responsive bus operations that respond quickly to passenger needs. The proposed method primarily involves two levels of functionality: (1) short-term forecasting of passenger demands using time-series prediction models, and (2) identification of service strategies coupled with the associated bus service segments using fuzzy clustering technologies in response to variances in passenger demand attributes and traffic conditions. The proposed bus operations method identifies the demand-responsive vehicle service strategies primarily according to the predicted up-to-date attributes of passengers’ demands, rather than deterministic passenger arrival rates, which were generally used in previous literature. In addition, the variation of traffic conditions along bus lines is considered in the proposed method. Results from numerical studies using real data of passengers’ demands, including passenger volume at each bus stop and the passenger origin-destination (O-D) patterns, are presented to demonstrate the effectiveness of the proposed method for real-world applications.     

研究生录取问题的优化模型与评述

针对2004年首届全国部分高校研究生数学建模竞赛的D题“研究生录取”问题的评卷情况,概括地介绍了这个问题的背景、评卷要点、答卷中存在的问题.并且给出了这个问题的一种有效的解决方法.     

An algorithm for DLP on anomalous elliptic curves over Fp

This paper improves the method of discrete logarithm on anomalous elliptic curves, and establishes an isomorphism from E(Fp) to Fp which can be more easily implemented. Fruthermore, we give an optimized algorithm for discrete logarithm on anomalous elliptic curves E(Fp).     

基于精英单亲遗传算法的冷链物流VRP模型优化研究

针对冷链物流配送的特殊性,探索冷链物流车辆路径问题(VRP)优化方案.首先,在保证货物不超载的条件下,建立基于时间和品质因素的顾客满意度约束的多配送中心VRP(MDVRP)模型;其次,采用重心分区法和改进的精英单亲遗传算法,求解顾客在配送中心的分配,确定配送车辆数以及顾客服务次序;最后,用Matlab工具编程对模型进行求解分析.结果表明构建基于满意度的冷链物流MDVRP模型更适合冷链物流配送最优路径选择,并且改进单亲遗传算法能够有效求解这类问题.     

基于最大期望满意度与背景风险的模糊投资组合模型研究

模糊投资组合是不确定性理论研究的重要领域.然而,由于人的理性局限性,投资者在决策的过程中,可能不是追求理性的效用最大化,而是追求心理满意度的最大化;在金融市场中,投资者不仅面临市场风险,也需要承担由自身因素产生的背景风险.因此,提出了一个考虑背景风险等因素的最大期望满意度模型,该模型的目标是最大化投资组合收益与最小收益证券的差值;最后,以上海证券交易所180指数的十支证券构成的的投资组合为例,分析了此模型在分散投资风险与增加满意度方面的有效性.     

Fitness of others' evaluation effect promotes cooperation in spatial public goods game

Payoff-driven strategy updating rule has always been adopted as a classic mechanism, but up to now, there have been a great many of researches on considering other forms of strategy updating rules, among which pursuing high fitness is one of the most direct and conventional motivations in the decision-making using game theory. But there are few or no researches on fitness from the perspective of others' evaluation. In view of this, we propose a new model in which the evaluation effect with fitness-driven strategy updating rule is taken into consideration, and introduce an evaluation coefficient to present the degree of others' evaluation on individual's behavior. The cooperative individuals can get positive evaluation, otherwise defective individuals get negative evaluation, and the degree of evaluation is related to the number of neighbors who have the same strategy of individual. Through numerical simulation, we find that the evaluation effect of others can enhance the network reciprocity, thus promoting the cooperation. For a strong dilemma, the higher evaluation coefficient can greatly weaken the cooperation dilemma; for a weak one, the higher evaluation coefficient can make cooperator clusters spread faster, however, there is no significant difference in the level of cooperation in the final stable state among different evaluation coefficients. The cooperation becomes more flourish as the number of fitness-driven individuals increases, when all individuals adopt fitness-driven strategy updating rule, the cooperators can quickly occupy the whole population. Besides, we demonstrate the robustness of the results on the WS small-world network, ER random network, and BA scale-free network.     

地方财政公共文化服务支出的效率评价——基于三阶段DEA窗口模型

利用三阶段DEA窗口模型对2005-2014年我国其中31个省市自治区的公共文化服务支出效率进行评估,结果表明:环境因素和随机误差对我国公共文化服务支出效率有显著影响;我国公共文化服务支出效率的总体水平较高,但呈下降趋势;我国公共文化服务支出效率存在明显的地区差异,且地区间效率水平无收敛趋势.     

援疆效果满意度的公因子分析:综合评价和政策取向——以南疆三地州数据为例

以居民对援疆政策满意度为出发点,前学者的研究基础上确定援疆政策效果的满意度的衡量指标,选取6个大方向31个指标来测量援疆效果满意度.通过南疆三地州进行实地问卷调查获得数据为样本,采用因子分析方法确定二级指标及三级指标的权重,进行对援疆政策效果满意度综合评价.研究结论是南疆居民对援疆效果的满意度总得分接近70分,说明总体满意度较高,其中满意度最高的为收入及补贴,排在第一位,排在末尾的就是教育领域,排在第二位的是住房建设,而基层服务的满意度仅仅高于教育领域,排在第五位.排在第三位的就是医疗,第四位才是居民出行为核心内容的基础设施建设.从而为援疆政策效果满意度优化,解决存在的问题,全面改善援疆政策效果提出政策建议.     

A residual-based message passing algorithm for constraint satisfaction problems

Message passing algorithms, whose iterative nature captures complicated interactions among interconnected variables in complex systems and extracts information from the fixed point of iterated messages, provide a powerful toolkit in tackling hard computational tasks in optimization, inference, and learning problems. In the context of constraint satisfaction problems (CSPs), when a control parameter (such as constraint density) is tuned, multiple threshold phenomena emerge, signaling fundamental structural transitions in their solution space. Finding solutions around these transition points is exceedingly challenging for algorithm design, where message passing algorithms suffer from a large message fluctuation far from convergence. Here we introduce a residual-based updating step into message passing algorithms, in which messages with large variation between consecutive steps are given high priority in the updating process. For the specific example of model RB (revised B), a typical prototype of random CSPs with growing domains, we show that our algorithm improves the convergence of message updating and increases the success probability in finding solutions around the satisfiability threshold with a low computational cost. Our approach to message passing algorithms should be of value for exploring their power in developing algorithms to find ground-state solutions and understand the detailed structure of solution space of hard optimization problems.