Preventing HIV in injection drug users: exploring the tradeoffs between interventions

Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs.     

在工程项目管理中实施过程管理的研究

传统的建设过程彼此分裂的特性，严重影响着工程建设的效率性和有效性。本文结合过程管理的思想，分析工程项目实施和管理的系统过程，探讨工程项目管理过程的识别与建立，并在此基础上提出建立工程项目管理的过程模型的方法。     

我国水上石油物流系统优化问题探讨

随着我国石油需求量及进出口量的不断增长,研究我国水上石油物流系统的优化问题日益重要,本文首先分析了水上石油物流系统研究的必要性,对国内外关于石油物流系统研究现状进行了评述,提出了我国水上石油物流系统优化问题的研究思路和方法.     

Carbon Taxes and Joint Implementation. An Applied General Equilibrium Analysis for Germany and India

Germany has committed itself toreducing its carbon emissions by 25 percent in2005 as compared to 1990 emission levels. Toachieve this goal, the government has recentlylaunched an environmental tax reform whichentails a continuous increase in energy taxesin conjunction with a revenue-neutral cut innon-wage labor costs. This policy is supposedto yield a double dividend, reducing both, theproblem of global warming and high unemploymentrates. In addition to domestic actions,international treaties on climate protectionallow for the supplementary use of flexibleinstruments to exploit cheaper emissionreduction possibilities elsewhere. One concreteoption for Germany would be to enter jointimplementation (JI) with developing countriessuch as India where Germany pays emissionreduction abroad rather than meeting itsreduction target solely by domestic action. Inthis paper, we investigate whether anenvironmental tax reform cum JI providesemployment and overall efficiency gains ascompared to an environmental tax reformstand-alone. We address this question in theframework of a large-scale general equilibriummodel for Germany and India where Germany mayundertake JI with the Indian electricitysector. Our main finding is that JI offsetslargely the adverse effects of carbon emissionconstraints on the German economy. JIsignificantly lowers the level of carbon taxesand thus reduces the total costs of abatementas well as negative effects on labor demand. Inaddition, JI triggers direct investment demandfor energy efficient power plants produced inGermany. This provides positive employmenteffects and additional income for Germany. ForIndia, joint implementation equips itselectricity industry with scarce capital goodsleading to a more efficient power productionwith lower electricity prices for the economyand substantial welfare gains.     

Modeling Disinterest and Dislike: A Bounded Bayesian Mixed Logit Model of the UK Market for GM Food

Mixed logit models represent a powerful discrete choice analytical model but require assumptions about the functional form of the parameter distributions. The use of unbounded distributions, such as the normal distribution, may be regarded as unsuitable where theory indicates that all are negatively affected by increases in an attribute, such as price. Bounded distributions such as the triangular and log-normal are unable to model the case where a section of the population is indifferent towards an attribute, while the remainder are negatively disposed toward it. Train and Sonnier’s bounded mixed logit model accommodates these features and is employed in this paper. A censored normal and Johnson’s S_b distribution are used to model preferences in the UK for food attributes, including price and GM technology. Bi-modal distributions are identified regarding GM food: some are unlikely to ever consume it, some are close to indifference and willing to consume at relatively small discounts while the remainder are fairly unresponsive to further price reductions.     

基于投入产出与解释结构建模法相结合的产业关联及层次识别建模

将投入产出方法与解释结构建模相结合,取长补短,提出了基于这两种方法相结合的产业关联层次识别的分析方法,并呈现了该方法的算法步骤、识别层次结果的基本特性以及其与以往产业关联分析方法的比较优势.最后以经统一调整的1997及2002年投入产出表为基础,对我国国民经济产业关联的层次识别进行实证分析,经对识别结果的跨期对比分析,证明该识别方法的解释效果良好.     

物流系统建模方法的研究

通过对现有系统建模分析方法的比较和分析,针对物流系统提出了一种集成建模分析GI-SIM法。该方法以概念、功能和动态建模思想为基础,以GRAI格、IDEFO和仿真技术为建模工具,满足了复杂物流系统的建模要求。最后,给出了GI-SIM法的建模步骤,并对其进行了总结和评价。     

物流系统规划-仿真集成化技术研究

通过对物流系统规划与仿真模型的分析，归纳出系统规划模型与系统仿真模型的共有属性和关系，采用集成化的技术，建立集成化规划一仿真系统模型，并通过Solidworks和Flexsim研究实现其集成化，并在相关课题中获得成功应用，突破了现有软件在规划与仿真之间数据共享的壁垒。     

军用车辆器材调拨业务流程重组模型研究

基于信息流分析,论述了军用车辆器材调拨系统中信息流程和业务流程的重组和优化应用,采用对象、岗位、任务三维视图的建模方法描述核心业务流程,提高了系统的可读性和可推广性。     

基于Petri网的物流分拣系统的建模与仿真

阐述了面向对象着色Petri网理论，并将它应用于物流分拣系统的建模，在分析该系统的基础上，建立了系统的面向对象着色Petri网模型，并借助AutoMod仿真软件对分拣系统进行了3D仿真。