利用可编程逻辑控制器实现交通信号灯的控制

文章主要是采用西门子公司的可编程逻辑控制器PLC-200来实现交通信号灯的控制。     

ASSET ALLOCATION AND ANNUITY-PURCHASE STRATEGIES TO MINIMIZE THE PROBABILITY OF FINANCIAL RUIN

In this paper, we derive the optimal investment and annuitization strategies for a retiree whose objective is to minimize the probability of lifetime ruin, namely the probability that a fixed consumption strategy will lead to zero wealth while the individual is still alive. Recent papers in the insurance economics literature have examined utility-maximizing annuitization strategies. Others in the probability, finance, and risk management literature have derived shortfall-minimizing investment and hedging strategies given a limited amount of initial capital. This paper brings the two strands of research together. Our model pre-supposes a retiree who does not currently have sufficient wealth to purchase a life annuity that will yield her exogenously desired fixed consumption level. She seeks the asset allocation and annuitization strategy that will minimize the probability of lifetime ruin. We demonstrate that because of the binary nature of the investor's goal, she will not annuitize any of her wealth until she can fully cover her desired consumption with a life annuity. We derive a variational inequality that governs the ruin probability and the optimal strategies, and we demonstrate that the problem can be recast as a related optimal stopping problem which yields a free-boundary problem that is more tractable. We numerically calculate the ruin probability and optimal strategies and examine how they change as we vary the mortality assumption and parameters of the financial model. Moreover, for the special case of exponential future lifetime, we solve the (dual) problem explicitly. As a byproduct of our calculations, we are able to quantify the reduction in lifetime ruin probability that comes from being able to manage the investment portfolio dynamically and purchase annuities.     

分销物流网络成本模型研究

通过分析分销物流网络成本构成，把分销物流网络成本分解为运输成本和配送中心内部的成本．并对各个成本要素进行了量化研究．进而得出了一个成本函数模型。通过一个实例分析了成本函数模型的应用。     

Attractiveness of cultural activities in European cities: A latent class approach

Cultural tourism behaviour and destination preference was analysed for 19 European capital cities, utilising the level of participation in cultural activities (participation) and the level of enjoyment of those cultural activities (attractiveness). A latent class model with three classes described the association in the data satisfactorily. Class 1 was labeled “low participation and high attractiveness”, Class 2 was labeled “high participation and high attractiveness”, and Class 3 was labeled “high participation and low attractiveness”. The Class 2 respondents with high participation and attractiveness had the highest cultural capital, and could be considered ‘specific cultural tourists’, whereas the Class 3 respondents could be considered ‘general cultural tourists’. Class 1 respondents, with relatively infrequent participation but high enjoyment, are potentially most interesting in marketing terms.     

Optimal Recycling System Design: With an Application to Sophisticated Packaging Tools

This paper deals with the mathematical analysis of product-process chains, aimed at the proper design of recycling systems. A modelling method is presented that can be applied to various chains. It is applied to a case in which a producer of sophisticated packaging tools requires insight into the many options of the design of a reuse/recycling chain. This is due to expectations for the near future that are related to extended product responsibility and the enforcement of recycling. Depending on the weight of different criteria and the choice of systems boundaries, optimal solutions can be selected. It turns out that the modelling method acts as a useful decision tool. A major bottleneck is the availability of data from suppliers and customers.     

论我国城市规划管理机制的问题与创新

要提高城市规划管理的效率和质量,须对现有的规划管理机制进行创新。本文在论述了我国城市规划管理机制现状的基础上,指出城市规划管理机制创新可从四个方面入手：建立科学化与民主化的决策机制、公开化与远东化的政府机制、法制化与完善化的监督机制、专业化与社会化的咨询机制。     

商品销售的动态规划模型及应用求解

商品销售公司在销售某种商品时，对不同的销售情况，可采用不同的决策，若每次决策又影响下一次决策，这是一个多阶段决策的问题。因此，可以建立一个马尔可夫过程，用值迭代法和动态规划最优化原理的策略迭代法合理地解决这一问题。     

收入水平、老龄化与营养摄入——基于广东省城镇住户数据的研究

进入新世纪以来,中国城镇居民面临营养不足与营养过剩并存的双重挑战。文章基于广东省城镇住户调查数据,运用门限模型对样本进行了异质性检验和高低收入样本的划分,在此基础上开展了高低收入样本下收入水平和老龄化对城镇居民营养摄入影响的实证分析。结果表明:总体样本中城镇居民营养摄入存在显著的收入门限效应;低于门限值样本的能量、蛋白质和脂肪需求的收入弹性分别为0.816、0.848和0.840,而当人均收入跨过门限值后,对应的收入弹性值减小为0.666、0.507和0.481;同时,老龄化对高收入组样本的营养摄入有负向显著性影响,但对低收入组样本的影响不显著。可见,在制定不同收入水平人群的食物与营养政策时,有必要采取差别化的干预措施,引导科学合理膳食,改善食物与营养结构;把重点人群作为突破口,开展老年人营养监测和膳食引导。     

二元结构下我国城镇劳动力市场中的性别工资差异研究

文章利用CHIP2002和CHIP2013数据,采用基于RIF无条件分位数回归的分解法,比较了不同时间维度和不同分位数水平上,我国农民工和城镇职工的性别工资差距及其形成机理。研究结果表明：第一,我国城镇劳动力市场中的性别工资差距不断扩大,其中农民工的性别工资差距全方位扩大,且低分位数上的增速最快,致使2013年其各分位数上的性别工资差距超过城镇职工。其中,低收入城镇职工与中等收入农民工群体的性别工资差距及其来源具有相似特征。第二,系数效应是造成城镇职工和农民工性别工资差异的主要因素,两个群体的性别歧视均有所增强。但与城镇职工相比,农民工群体的性别歧视较大且增速较快。由于低收入群体中性别歧视的快速增长,城镇劳动力市场中遭受性别歧视最严重的群体由2002年的高收入的城镇女性职工和高收入的女性农民工,转变为2013年中等收入的女性农民工和低收入的城镇女性职工。第三,尽管针对中高收入城镇女性职工的市场前歧视和市场歧视均有所弱化,但低收入的城镇女性人力资本水平及其回报率仍低于同类男性,呈现与女性农民工相似的特点。上述结果意味着,城镇劳动力市场中不同户籍、不同收入水平的女性,遭受着不同程度的性别歧视,应针对不同群体采用差别化的性别干预政策。     

中国儿童编程教育产业发展研究

在未来人工智能和万物互联的时代,机器智商是成功的关键,而人是通过程序语言与机器进行沟通交流。结合儿童认知发展和程序语言的特点,以及当前国际教育发展的趋势,儿童应尽早接触和学习编程以满足未来社会发展的需要。文章从国家、学校、公益、创业四个方面分析中国发展儿童编程教育的现状和问题,通过层次分析法（AHP）对各方面的情况进行量化分析。得出结论,政府对发展儿童编程教育的支持才刚开始,学校试点局限于一线城市,公益缺乏传统,而创业却有不错的发展势头,可以依托创业来发展儿童编程教育。并提出建议,建立国家重视、学校支持、公益行动、创业有效的协同机制以发展儿童编程教育产业。