A multi-objective and multi-period optimization model for urban healthcare waste’s reverse logistics network design

Various types of healthcare waste (or medical waste) generated by urban healthcare activities have increased due to the expansion of urban population and medical needs. As healthcare wastes are harmful to both the environment and human health, managing medical waste is becoming progressively more important. Constructing an optimized medical waste recycling network is one of the key problems in the management of urban healthcare waste. This paper conducts a two-stage reverse logistics network design for urban healthcare waste. The first stage involves the prediction of the amount of medical waste. Based on the Grey GM(1,1) prediction model, the amount of medical waste in multi-period of the target hospitals is predicted. In the second stage, a multi-objective model aimed at minimizing operating costs and minimizing environmental impact is developed for facilities allocation decisions, which include the configuration of key facilities such as hospitals, collection centers, transshipment centers, processing centers, and disposal sites, as well as medical waste flow control among facilities. A dynamic approach for the healthcare waste reverse logistics network is constructed by combining the Grey GM(1,1) prediction method with multi-objective optimization model. Sensitivity analysis of key parameters has been performed to analyze their impact on network performance. Some insightful management practices have been revealed.

     

基于二阶段随机规划的城市医疗废弃物回收网络设计

城市医疗废弃物日益增加,且回收需求量受诸多因素的影响,难以准确预测,假定回收需求为确定值的医疗废弃物网络优化设计不能与实际需求相匹配。本文考虑了离散随机参数环境下,医疗回收网络设计中选址规划、分配计划及运输规划的协同优化问题,建立了以选址成本、运输成本最小为目标,设施与车辆能力限制为约束的二阶段随机规划模型。根据模型特点,设计了基于Benders decomposition的求解算法,同时,设计了一系列加速技术用于提高算法的求解效率。最后,以国内某城市医疗回收网络为背景设计算例,检验本文模型和求解策略的可行性和有效性。结果表明：相比确定性规划,随机规划的解能够节约总成本,结合一系列加速技术的Benders decomposition方法比CPLEX与纯的Benders decomposition更有优势。     

Analysis of Local Acceptance of a Radioactive Waste Disposal Facility

Like many other countries in the world, Korea has struggled to site a facility for radioactive waste for almost 30 years because of the strong opposition from local residents. Finally, in 2005, Gyeongju was established as the first Korean site for a radioactive waste facility. The objectives of this research are to verify Gyeongju citizens' average level of risk perception of a radioactive waste disposal facility as compared to other risks, and to explore the best model for predicting respondents' acceptance level using variables related to cost-benefit, risk perception, and political process. For this purpose, a survey is conducted among Gyeongju residents, the results of which are as follows. First, the local residents' risk perception of an accident in a radioactive waste disposal facility is ranked seventh among a total of 13 risks, which implies that nuclear-related risk is not perceived very highly by Gyeongju residents; however, its characteristics are still somewhat negative. Second, the comparative regression analyses show that the cost-benefit and political process models are more suitable for explaining the respondents' level of acceptance than the risk perception model. This may be the result of the current economic depression in Gyeongju, residents' familiarity with the nuclear industry, or cultural characteristics of risk tolerance.     

A systems simulation model of the Kenyan economy

This paper describes a systems simulation model of the national economy of Kenya. The model contains an input/output production component linked to a consumption component, disaggregated into nine income classes. Capital formation and government are integrated into the model as interactive elements. The model is demand driven and thus growth rates in the productive sectors are generated endogenously as a function of demand. The model has been used by the Kenyan Ministry of Finance and Economic Planning for forecasting and policy evaluation problems. A contributory factor in the successful implementation of the model is its ability to supply detailed quantitative forecasts which, in a developing country, are not readily available from routine sources. In addition, the model deals explicitly with income distribution and inflation consequences which are issues of current concern to local development planners.     

Stakeholder Views on Flood Risk Management in Hungary''s Upper Tisza Basin

With escalating costs of flood mitigation and relief, a challenge for the Hungarian government is to develop a flood mitigation and insurance/relief system that is viewed as efficient and fair by the many stakeholders involved. To aid policymakers in this task, this article reports on a recent study to elicit stakeholder views on flood risk management in the Upper Tisza Basin, including views on appropriate means of reducing losses and for transferring the residual losses from the direct victims to taxpayers or an insurance pool. This study is part of a project to develop an integrated approach to flood risk management coordinated by the International Institute of Applied Systems Analysis (IIASA) in collaboration with Swedish and Hungarian researchers. The discussion begins by describing the background of flood risk management problems in the Upper Tisza Basin. The results of interviews carried out with selected key stakeholders and the results of a public survey eliciting views on flood risk management are reported. The final section draws conclusions on incorporating stakeholder views into a flood risk management model, which will be used to illustrate policy paths at an upcoming stakeholder workshop. The conclusions are also of direct interest to Hungarian policymakers.     

高等教育最优投资双层规划模型研究

高等教育投资具有"双层"的特点,上层为省级主管部门,下层为高等学校。本文成功运用了双层规划模型,在不考虑高校自筹发展资金投入的情况下,建立了高等教育最优投资双层规划模型,研究了模型最优解的存在性,给出并证明了模型最优解的等价形式,设计了模型解的算法并进行了算法复杂性分析。通过求解模型,可以同时得到省级主管部门和高等学校的最优投资决策方案。文章最后还给出了考虑高校自筹发展资金的两种情况下建立投资模型和求得最优解的方法。     

RELIABILITY-CONSTRAINED PRICING,CAPACITY, AND QUALITY: AN ILLUSTRATION OF ECONOMIC CONCEPTS TO POSTAL SERVICES

A model is developed from which welfare-optimal prices, capacities, and reliabilities for a service provider are simultaneously determined. Solutions are determined under conditions of stochastic demand subject to a reliability constraint on service quality. Both quality of service provided, as well as price, impact on demand for services rendered. Results indicate that (i) optimal prices are equated to the reliability-constrained marginal costs, (ii) optimal reliabilities require that the marginal benefits of increasing reliability are equated to the marginal costs of doing so, and (iii) optimal capacity allocation involves minimizing the system's expected costs subject to meeting the prespecified reliability constraint for service quality. The model is applied to postal delivery services in light of the growing competition that has emerged in this industry.     

基于生产者责任延伸的新能源汽车动力电池回收帕累托均衡

动力电池回收过程涉及到产业链上多个利益主体,存在回收责任界定不清、企业回收积极性不高、回收成本居高不下等问题。考虑在生产者责任延伸理念下,整车企业承担回收的主体责任,构建整车企业、动力电池生产企业和第三方回收拆解企业的三方博弈模型,通过模型求解,分析帕累托均衡状态。研究结果表明：不同市场环境因素对各企业策略选择的影响强弱不尽相同,而作为回收责任的源头主体,整车企业策略选择极大程度上决定了电池生产企业承担延伸责任的积极性,对构建良性回收网络有关键性影响;同时不同主体间的研发补贴作用有所不同,持续增加补贴会起到一定的反作用。     

Financing Liabilities Under Superfund

One of the more critical environmental risk areas involves the financing of cleanup costs associated with past improper disposal of hazardous wastes. These costs will run into the tens of billions of dollars. The federal Superfund program and related state programs are the driving forces for cleaning up hazardous waste. Under Superfund, the government collects taxes and coordinates cleanup strategies, and searches for potentially responsible parties (generators, disposers, transporters) to assist in financing the cleanup. To lessen the financial impact, responsible parties are looking to their liability insurers to provide coverage under old general liability insurance policies. Insurance companies contend that Superfund liabilities are not covered under liability policies. The paper examines the various financing methods and liabilities produced by Superfund. Particular emphasis is placed on developments in the courts which are resulting in a significant shift in the financial responsibilities to the insurance industry. Broad estimates of the financial impact of Superfund liabilities are developed. Finally, several public policy issues, which are raised by the topics exmained in this paper, are discussed.     

一类污水处理项目的运营与排污者行为动态分析

本文针对污水处理项目运营风险高、企业偷排行为控制难问题,首先依据排污信息和排污价格的波动与否,构建了4种计算实验情景;然后针对各种情景分别设计了污水处理价格形成机制、居民和企业社会属性与行为的变化规则,分析了经济压力、社会影响以及政府监管对排污价格形成、排污者行为变化的影响;最后运用计算实验方法模拟了污水处理项目运营与排污者行为在4种情景下的动态变化。结果表明:合理的静态定价策略要优于运营商动态定价策略;动态外部环境既给污水处理项目的运营带来风险,又给政府对企业的监管带来不便;单纯的市场价格机制或政府监管机制很难有效控制偷排现象,也不一定能实现居民的节水减排,企业和运营商的逐利行为可能会使得目标落空。     

Resilience Analytics with Application to Power Grid of a Developing Region

Infrastructure development of volatile regions is a significant investment by international government and nongovernment organizations, with attendant requirements for risk management. Global development banks may be tasked to manage these investments and provide a channel between donors and borrowers. Moreover, various stakeholders from the private sector, local and international agencies, and the military can be engaged in conception, planning, and implementation of constituent projects. Emergent and future conditions of military conflict, politics, economics, technology, environment, behaviors, institutions, and society that stress infrastructure development are prevalent, and funding mechanisms are vulnerable to fraud, waste, and abuse. This article will apply resilience analytics with scenario‐based preferences to identify the stressors that most influence a prioritization of initiatives in the electric power sector of Afghanistan. The resilience in this article is conceived in terms of the degree of disruption of priorities when stressors influence the preferences of stakeholders, and ultimately a prioritization of initiatives. The ancillary results include an understanding of which initiatives contribute most and least across strategic criteria and which criteria have the most impact for the analysis. The article concludes with recommendations for risk monitoring and risk management of the portfolio of stressors through the life cycle and horizon of grid capacity expansion.     

考虑供应风险的多源应急物资采购双层规划模型

自然灾害频繁发生,事故灾难不断涌现,公共卫生事件猝不及防,社会安全风险交织叠加,给人们的生产和生活带来了巨大的风险和不确定性。在突发事件背景下,考虑应急物资供应中的各类风险,激励多源应急物资的稳定供给,受到党和政府高度重视。应急物资供应有哪些风险,如何规避这些风险,针对多种渠道的采购,如何优化采购结构。这些问题是本论文关注的重点。本文以政府、制造型企业、受灾地区民众为决策主体的三级供应链为基础,构建了上层以整个供应链系统收益最大化为目标函数、下层以供应风险最小化为目标函数的双层规划模型,对不同情景下物资采购订单的分配进行研究。在此基础上,本文以某市洪涝灾害为例进行分析,证明了模型的可行性,并探究了供应风险变化对物资采购订单分配、以及整个供应链系统收益的影响,以期为政府应急物资采购决策提供参考性建议。     

Developing and Testing a Facility Location Model for Canadian Nuclear Fuel Waste

The purpose of this paper is to develop and test a facility location model for the siting of a nuclear fuel waste disposal facility in Canada. The model is based on successful Canadian siting processes related to hazardous waste and low level radioactive waste facilities, as well as attributes of facility siting found in the literature. The proposed model was presented to a sample of participants in the federal environmental assessment review of the technical feasibility of the Canadian Nuclear Fuel Waste Disposal Concept (CNFWDC) held throughout Canada in 1990. Results demonstrate that despite the fact that over half of the survey respondents did not support the CNFWDC during the public hearings, the majority favorably rated the proposed facility location model. Components of the model that were tested included siting criteria and goals, decision-making groups, and siting safeguards. On the basis of these results, it is concluded that the siting of a nuclear fuel waste disposal facility must make the decentralization of decision-making authority to local communities and governments a priority.     

逆向供应链中电子废弃产品回收定价和补贴策略研究

随着废弃电子产品的大量涌现和社会环保意识的增强,废弃电子产品的回收处理成为社会关注的热点问题之一。在现有的文献研究中,更多的是从逆向供应链系统化的视角关注价格或税收政策对回收商或处理商的运营效率、积极性的影响,逆向供应链激励的关键问题即如何确定回收价格和补贴方面的研究却较少见。本文基于社会福利最大化的视角,建立斯塔克伯格博弈模型（社会福利模型）来确定逆向供应链分散管理中的回收价格和社会最优补贴费,该模型可以检验分散管理系统（环保局作为领导者、MIS和回收商作为追随者）中回收逆向供应链的回收价格和补贴的激励效应。通过社会福利模型和资金平衡模型的比较,以及比较案例的数值演算,结果发现：达到市场最优销售数量和向顾客提供回收废弃电子产品的最优奖金的状况下,销售商和回收商处于平衡状态;社会福利模型中窒息价格、零奖金对应的基准收集数量、相对于奖金的收集量敏感度等因素对社会福利的影响均优于资金平衡模型。     

考虑交通时间与设备转换时间的跨区域就医调度优化问题

在资源共享时代背景下,跨区域就医可以很好地解决患者日益增长的就医需求与医疗资源紧张的矛盾。本论文以医疗联盟为研究对象,在关键医疗资源共享的前提下,通过患者跨区域就医实现就医诊断延误最小化,以满足患者就医需求。本研究同时考虑了患者跨区域交通时间与基于患者诊断类型的设备转换时间,以最小化患者就医总延迟为目标,分配患者就诊医院及优化患者就诊/检查顺序。针对该问题,论文首次提出以最早交货期原则（EDD rule）为基础,以患者再分配为主导的EDD-ReAss1和EDD-ReAss2启发式算法,结合局部搜索算法以进一步提高就医调度方案的质量,缩短患者诊断/检查等待时间。实验结果表明,新启发式算法EDD-ReAss1和EDD-ReAss2算法性能显著好于EDD,SPT和LPT等调度规则;在较短运算时间内Swap局部搜索算法性能最优。     

Multiproduct cost-volume-profit model with product limits

A multiproduct cost-volume-profit model is extended to incorporate sales or product capacity limits for each product, required rate of return on sales, and the tax rate depending on profit levels as determined by the government. The model also deals with overhead costs that are traceable to a group of products but which cannot be allocated to individual products within the group to any reasonable accuracy. To solve the model, an algorithm is constructed to determine the required volume for each product that will achieve the best possible rate of return on sales revenue. Based upon the dBase Database Management System and the CVP model, a user-friendly menu-driven interactive decision support system is developed. The model algorithm and decision support system is illustrated with an example consisting of five products. Various reports generated by the interactive decision support system are also presented.     

Options in Radioactive Waste Management Revisited: A Proposed Framework for Robust Decision Making

Deregulation, with concurrent pressure on electricity utilities, has fundamentally changed the once-"closed" radioactive waste management system controlled by the so-called "nuclear establishment." Advocacy coalitions may change-who knows in which direction-but policy learning may also take place. This article presents a framework to evaluate the management options for a specified concept of "sustainability." When weighing the different objectives in view of the long-lasting potential danger of radiotoxic substances, the overall goal of a sound waste management system is to demonstrate safety. The first-priority objective of a disposal system, therefore, is its stability so that it can comply with the protection goal, that is, the long-term protection of humans and the environment from ionizing radiation. The complementary objective is flexibility, defined here as intervention potential. Because trade-offs within the "sustainability triangle" of ecology, economy, and society are unavoidable, the concept of "integral robustness"-both technical and societal-is introduced into radioactive waste management. A system is robust if it is not sensitive to significant parameter changes. In the present case, it has to have a conservative, passively stable design with built-in control and intervention mechanisms. With regard to technical implementation, a concept called "monitored long-term geological disposal" is presented. Such an "extended" final disposal concept emphasizes technical robustness, recognizes evaluation demands (for a potential break-off of a project), and enhances process-based transparency. This open approach admittedly sets high challenges with regard to technicalities as well as the institutional setting and the management process. It requires "mutual learning" by and from all stakeholders to achieve a truly sustainable radioactive waste management system.     

On-Site Storage of High Level Nuclear Waste: Attitudes and Perceptions of Local Residents

No public policy issue has been as difficult as high-level nuclear waste. Debates continue regarding Yucca Mountain as a disposal site, and—more generally—the appropriateness of geologic disposal and the need to act quickly. Previous research has focused on possible social, political, and economic consequences of a facility in Nevada. Impacts have been predicted to be potentially large and to emanate mainly from stigmatization of the region due to increased perceptions of risk. Analogous impacts from leaving waste at power plants have been either ignored or assumed to be negligible. This paper presents survey results on attitudes of residents in three counties where nuclear waste is currently stored. Topics include perceived risk, knowledge of nuclear waste and radiation, and impacts on jobs, tourism, and housing values from leaving waste on site. Results are similar to what has been reported for Nevada; the public is concerned about possible adverse effects from on-site storage of waste.     

基于动态博弈的远程医疗政策与患者社会福利研究

为了研究远程医疗的有效政策以及政策对患者社会福利的影响,考虑一个由政府、医院和患者三个主要利益相关者构成的医疗系统,利用动态博弈等理论建立了三种博弈模型：完全竞争条件下的两阶段动态博弈模型、医保报销比例政策下的三阶段动态博弈模型、医保报销比例和医疗服务价格限制双重政策下的三阶段动态博弈模型。研究结果表明,患者社会福利在完全竞争博弈中最低,在医保报销比例政策下的博弈中次之,在医保报销比例和医疗服务价格限制双重政策规制的博弈中最高。将远程医疗纳入医保范围,并给予较高的医保报销比例,既有利于远程医疗市场占有量的增长,又有利于患者社会福利的增加。但较高的医保报销比例会使远程医疗和传统医疗服务价格都显著上涨,必须施加医疗服务价格限制,以控制价格的上涨,减少社会医疗成本。最后,算例和敏感性分析验证了模型的有效性和正确性。     

双层规划在城市交通污染控制中的一个应用

本文从控制城市交通污染的角度出发,考虑到用户的路径选择行为,采用双层规划模型描述城市交通管理与污染控制问题,并给出了相应的启发式求解算法及算例,在此基础上,提出了城市交通管理与污染控制框架。