考虑质量成本的再制造系统批量计划综合优化

研究需求和再制造率不确定下整个再制造系统的综合协调问题,帮助再制造商制定各环节批量决策以实现整体最优． 首先,考虑对应其拆卸后不同质量状况的差异再制造成本,构建能反映质量成本的拆卸和再制造总成本模型; 接着,考虑新零部件采购提前期,利用两阶段利润函数的思想,构建包括拆卸、再制造和重新装配3个子系统中所有成本因素、以利润最大化为目标的优化模型; 然后,求解最优再制造/拆卸比率、拆卸批量、再制造/采购批量和重新装配批量; 最后,通过算例验证并讨论平均再制造零部件获取成本对再制造批量、采购批量、拆卸和再制造总成本以及总利润的影响,再制造/拆卸比率和单位拆卸成本的关系．     

第Ⅱ类拆卸线平衡问题建模及优化

环境资源问题日益凸显、人们环保意识的增强以及经济利益的驱动，促使社会进行废旧产品回收再利用，以发展绿色经济。拆卸作为回收再利用过程中的核心环节，采用流水线的方式组织产品精细化拆卸，可实现资源最大化价值。然而，零部件作业任务在流水线上分配排序过程复杂，各工作站上的作业负荷需保持相对均衡，才能保证拆卸线高效运行。为此，本文在拆卸线工作站数量固定的情况下，以最短节拍时间和均衡任务在工作站上的分配为目标，建立第Ⅱ类拆卸线平衡问题优化模型，并提出一种并行动态邻域深度搜索算法进行求解。所提算法采用动态搜索机制实现解在各邻域结构集内的并行深度搜索；通过设置扰动阈值对解实施干扰，以加快跳出局部最优；在节拍时间调整过程中，采用基于二分法的定界策略，以实现向最优节拍时间的快速靠拢。最后，通过不同规模算例验证了模型的有效性以及算法的高效性。     

基于GERT随机网络的废弃回收预测模型研究

在阐述回收处理业务流程的基础上,分析其不确定性;运用随机网络系统模型的相关理论构建GERT网络模型,探讨产品回收再制造零部件和可再生材料的预测模型。该模型既可以预测出废弃产品返回数量、回收处理过程中的再造零部件和可再生材料的比例和数量,又可以预测出它们的期望返回时间。最后,以打印机的回收再制造为例,对模型进行了实际应用。     

作业时间依赖顺序的拆卸线平衡多目标优化

在废旧产品拆卸时无先后关系约束的任务之间可能存在拆卸干扰，使任务作业时间依赖于拆卸顺序，导致产品总作业时间不确定，从而影响拆卸线的平衡。为此，考虑拆卸过程中任务间的相互干扰，以最小化拆卸成本和环境危害为目标，构建作业时间依赖顺序的拆卸线平衡多目标优化模型，并提出一种Pareto人工蜂群算法进行求解，采用混合生成法保证种群质量与多样性，设计变邻域深度搜索策略以提高雇佣蜂局部开采效率，为降低侦察蜂探测的盲目性采用基于外部存档的单点变异算子进行搜索。最后通过算例与实例验证算法的有效性以及平衡任务在拆卸线上分配的重要性。     

基于补偿合约的供应链定价与能力设计的协调问题研究

研究和分析了在需求不确定并且受价格影响的情况下,供应链中制造商与供应商的产品定价与能力设计的协调问题。制造商从供应商处采购用于产品生产的关键零部件,供应链面临的潜在需求服从随机分布,有效需求则受产品定价的影响。当供应商的生产能力出现约束时,制造商可以从外部其他渠道获取关键零部件,但是需要付出一个更高的采购价格。制造商确定产品的销售价格,供应商确定生产能力。分析比较了在集成供应链与独立决策的供应链中的定价与能力计划策略,提出了一种能够有效协调制造商和供应商的决策行为的补偿合约。最后,进行了数值分析,证明补偿合约的有效性。     

废旧产品回收再制造计划模式研究述评

在分析再制造基本概念及流程的基础上,从废旧产品回收计划、回收产品拆卸计划、再制造生产计划等三个方面对国内外再制造计划模式的研究现状进行综述。指出目前研究中对再制造过程的不确定性特征认识不足、对产品回收后的状态不能有效预测、对不确定情形的产品拆卸计划研究较少、对于再制造生产计划与控制缺乏系统研究。针对上述不足,提出了进一步研究的方向。     

考虑成本共担的复杂产品零部件协同创新Stackelberg优化研究

在技术不断升级改造背景下,复杂产品作为高端装备产品的代表,它的工艺技术创新水平在一定程度上代表了制造业的技术水平。由数以万计的零部件所组成的复杂产品在生产研发过程中,零部件的生产创新直接决定复杂产品的生产创新,而如何从供应链角度去研究零部件生产协同问题来实现复杂产品的生产协同成为难点。本文基于复杂产品协同制造模式,从主制造商激励视角出发,考虑零部件的工艺创新和装备创新,研究主制造商成本共担机制下复杂产品零部件的协同创新问题。首先,为激励供应商进行创新积极性,通过设计创新程度相关参数,依据零部件工艺创新程度和装配创新程度构建了复杂产品生产函数,探讨了主制造商成本共担激励策略,建立了基于成本共担协同创新Stackelberg博弈模型;其次,借助于成本共担与不共担情形下对比研究了最优创新程度水平以及主制造商最佳成本共担比例;最后,借助某商用飞机电力支持系统进行数值验证,结果表明：供应商最优成本共担比例和工艺弹性和装配弹性呈正比,最优工艺创新程度和装配创新程度与工艺弹性和装配弹性呈反比例关系,当弹性在一定范围变动时,成本共担要比成本不共担要好;当弹性超过变动范围时,则不再分担成本进行激励。本文系统分析了成本分担下零部件创新程度问题,为供应商和主制造商长期激励合作提供了一定决策依据。     

加权局域世界网络组织技术扩散模型及仿真分析

采用仿真方法模拟技术在网络组织间扩散过程,分析了加权局域世界网络组织的网络结构、演化、结点、局域世界特征对技术扩散率的影响.仿真结果表明:新结点加入和旧结点退出概率越小、网络平均邻结点数越大、结点学习能力越强,技术扩散速率越快;静态网络中,局域世界内的联系比在不同局域世界间的联系更有利于整个网络组织技术扩散,而在动态演化网络中,这种效果主要集中在技术扩散初期;静态网络中,技术扩散初期局域世界内以结点强度偏好性作为连边原则比随机连边原则更有利于技术扩散,但在动态演化网络中,这种效果持续整个技术扩散过程;动态网络中,“结点度偏好性选择连接原则”比“适应度偏好性选择连接原则”更有利于技术扩散.     

面临零部件过期的产品销售与售后服务供应链合同分析

备件库存管理对产品售后服务至关重要,而零部件过期会影响备件库存的正常补货,进而延长故障修复时间,降低产品可用率.终身购买作为应对零部件过期的重要策略,被广泛运用在实践中.然而,学术论文中关于零件过期对供应链管理影响的研究并不多见.本文建立了同时考虑产品销售和售后服务情况下的供应链动态博弈模型,分析了客户的产品订购批量、供应商的定价决策以及备件终身购买批量之间的相互作用,探讨了保修期和零部件过期采购成本对合同均衡策略和供应链利润的影响.结果表明,当零部件过期采购成本较低时,供应商可以在延长保修期的同时降低备件库存数量,并允许一定程度的备件缺货水平,从而最大化提升产品可用率所带来的收益.同时,应当适当降低对备件数量的技术标准要求.而当零部件过期 采购成本较高时,供应商应当避免提供较长的保修期,并增加备件终身购买批量以减小零部件过期带来的负面影响.此时,备件数量的技术标准则可以适当提高.     

面临零部件过期的产品销售与售后服务供应链合同分析北大核心CSCDCSSCI

备件库存管理对产品售后服务至关重要,而零部件过期会影响备件库存的正常补货,进而延长故障修复时间,降低产品可用率.终身购买作为应对零部件过期的重要策略,被广泛运用在实践中.然而,学术论文中关于零件过期对供应链管理影响的研究并不多见.本文建立了同时考虑产品销售和售后服务情况下的供应链动态博弈模型,分析了客户的产品订购批量、供应商的定价决策以及备件终身购买批量之间的相互作用,探讨了保修期和零部件过期采购成本对合同均衡策略和供应链利润的影响•结果表明,当零部件过期采购成本较低时,供应商可以在延长保修期的同时降低备件库存数量,并允许一定程度的备件缺货水平,从而最大化提升产品可用率所带来的收益.同时,应当适当降低对备件数量的技术标准要求.而当零部件过期采购成本较高时,供应商应当避免提供较长的保修期,并增加备件终身购买批量以减小零部件过期带来的负面影响.此时,备件数量的技术标准则可以适当提高.     

Pricing decisions in a multi-criteria setting for product recovery facilities

Unpredictability in the arrival time and quantity of discarded products at product recovery facilities (PRFs) and varying demand for recovered components contribute to the volatility in their inventory levels. Achieving profit under such capricious inventory levels and stringent environmental legislations remains a challenge to many PRFs. This paper presents a multi-criteria decision model to determine a pricing policy that can simultaneously address two issues: stabilize inventory fluctuations and boost profits. The model considers that PRFs passively accepts discarded products as well as acquires them proactively if necessary. Under a multi-criteria setting, the current work determines prices of reusable and recyclable components to maximize revenue and minimize product recovery costs. A genetic algorithm is employed to solve the multi-criteria decision making problem. Sensitivity analysis is performed to investigate the effect of sorting yield, disassembly yield, and reusable component yield on the profits, prices, inventory levels, and disposal quantities.     

Exact methods in optimum disassembly sequence search for problems subject to sequence dependent costs

Disassembling complex products is formally approached via network representation and subsequent mathematical modeling, aimed at selecting a good or optimum sequence of disassembly operations. This is done via heuristics, metaheuristics or mathematical programming. In contrast with heuristics and metaheuristics, which select a near-optimum solution, mathematical programming guarantees the selection of the global optimum. This problem is relatively simple if the disassembly costs can be assumed sequence independent. In practice, however, sequence dependent disassembly costs are frequently encountered, which causes NP-completeness of the problem. Although methods, e.g., based on the two-commodity network flow approach, are available to solve this constrained asymmetric Traveling Salesperson problem rigorously, this requires the introduction of integer variables. In this paper, a modification of the two-commodity network flow approach is proposed, which reduces the number of integer variables. This is applied to product structures that can be represented by a disassembly precedence graph. It is demonstrated that use of integer variables is completely avoided by iteratively solving a binary integer linear programming problem. This appears to be more efficient than solving the corresponding integer linear programming problem. It is demonstrated, on the basis of some cases, that this method might provide the exact solution of problems with increased complexity compared to those discussed so far in the literature. This appears particularly useful for evaluating heuristic and metaheuristic approaches.     

Production planning and control for remanufacturing: literature review and analysis

This article reviews the literature on production planning and control (PPC) for remanufacturing. The objectives are threefold: to determine whether the gaps identified by Guide (Guide Jr, V.D.R., 2000. Production planning and control for remanufacturing: industry practice and research needs. Journal of Operations Management, 18, 467–483) on the subject with respect to the main complicating characteristics of remanufacturing have been fulfilled; to classify the literature based on an appropriate structure to obtain a better understanding of the subject identifying sources of future research and to provide a useful source for scholars and practitioners. Seventy-six papers were examined and classified. It was found that none of the studies deals simultaneously with all of the complicating characteristics, and that more practical research is needed. In addition it was found that we lack studies regarding forecasting and aggregate planning considering disassembly of returned products, material matching restrictions or stochastic routings, master production scheduling considering material matching restrictions or stochastic routings, ordering system and capacity planning considering material matching restrictions and inventory control and management considering stochastic routings.     

Determining optimal disassembly and recovery strategies

We present a stochastic dynamic programming algorithm for determining the optimal disassembly and recovery strategy, given the disassembly tree, the process-dependent quality distributions of assemblies, and the quality-dependent recovery options and associated profits for assemblies. This algorithm generalizes the one proposed by Krikke et al. (International Journal of Production Research 1998; 36(1):111–39) in two ways. First, there can be multiple disassembly processes. Second, partial disassembly is allowed. Both generalizations are important for practise.     

Dezentrale Koordination von Stoffströmen in Recyclingnetzwerken

New legal regulations assign an extended product responsibility to the manufacturers, e.g. in the field of Waste Electrical and Electronic Equipment. Therefore, recycling of discarded products becomes increasingly important. For Waste Electrical and Electronic equipment, recycling is usually carried out by service providers, which are organised in recycling networks. In such networks of independent companies, centralized planning is not possible and therefore, a decentralized coordination mechanism is necessary. Within the article, a 2-level coordination approach is developed. This approach seems to be a good starting point for an efficient assignment of recycling tasks within the network, if a central planner is not present. The functionality of the approach is demonstrated based on an example.     

A general approach to disassembly planning and control

Closing product and material cycles have emerged as a paradigm for industry in the 21st century, and are directed towards an economical and responsible use of our limited resources. Disassembly plays a key role in recycling. It enables the recovery of functioning components for re-use of pure materials for re-utilization and the separation of harmful substances. Major challenges are presented by the enormous variety of products to be disassembled, by uncertainty as to quantity and by their unknown properties. An appropriate planning and control of disassembly processes is essential for an economic disassembly. Based on an investigation of the suitability of common production planning and control (PPC) methods for disassembly, a specific disassembly planning and control concept (DPC) is outlined.     

Reducibility of stochastic networks

This paper deals with the problem of reducing a stochastic network to one equivalent activity. The problem was motivated by the question of determining or approximating the probability distribution function of the duration of the longest or shortest path in a stochastic network. We define a particular reduction and use it to characterize the reducibility of such a network. The network can be reduced to one equivalent activity if the network does not have a special graph which we call the ‘interdictive graph’, or IG for short. If an IG is embedded in the network, the network is irreducible. In this case, its reduction becomes possible by duplicating some of the arcs in the irreducible network. The concept of duplicating an arc is introduced, then it is used to identify the arcs which can be duplicated. The reduction procedure is stated and illustrative examples are provided. An upper bound on the number of duplications is established.     

Literature review: Strategic network optimization models in waste reverse supply chains

In scientific literature two large, partly overlapping areas regarding the environmental and economical attractive removal of waste coexist: reverse logistics and waste management. Both fields study, among other topics, the flows of discarded products leaving the end consumer. This review takes an integrated point of view on reverse logistics and waste management and aims at a better integration. More specifically, it gives a concise but complete overview of the efforts already performed in the area of strategic network design in waste reverse supply chains by means of combinatorial optimization models. Its purpose is to guide interested readers and researchers directly to publications of their interest, and let them identify courses other than the well-worn paths. Among others, we explicitly refer to (1) the importance of environmental, social and performance indicators in multi-objective models, (2) the potential of incorporating the different waste reverse supply chain stakeholders into the network design model, (3) the consideration of future waste reverse supply chain developments like extended producer responsibility schemes and the circular economy and their challenges, and (4) better heuristics to deal with the increasingly complex strategic network design models.