A capacitated production planning problem for closed-loop supply chain with remanufacturing

This paper addresses a dynamic capacitated production planning problem in steel enterprise employing a closed-loop supply chain strategy, in which the remanufacturing process is applied. Particularly, the remanufacturing problem considered in this paper is obviously different from the typical lot-sizing problems, within which all demands are met by production or remanufacturing without backlogs; the production, inventory, and remanufacturing levels all have limits; both the production and remanufacturing setup cost functions are arbitrary and time-varying; the objective is to minimize the total cost. Firstly, the closed-loop supply chain with remanufacturing model is formulated. Then, the genetic algorithm heuristic approaches are proposed to solve the NP-hard problem. Finally, a computational experiment is presented which can solve the 200 size problem efficiently. Furthermore, the comparisons against the branch and bound method show the effectiveness and efficiency of the proposed approach for solving the large size remanufacturing problem.     

Designing and planning a multi-echelon multi-period multi-product closed-loop supply chain utilizing genetic algorithm

Designing and planning a closed-loop supply chain in a comprehensive structure is vital for its applicability. To cope with the design and planning issue of a comprehensive closed-loop supply chain network, this paper develops an extended model, which is multi-echelon, multi-product, and multi-period in a mixed integer linear programming framework. The word “comprehensive,” in our mathematical approach, in designing and planning a closed-loop supply chain problem, can be analyzed from two complementary angles: including all possible entities (facilities) of a real condition and considering minimum limitations on possible flows between entities. In our proposed model, customers can be supplied via manufacturers, warehouses, and distributors, as an example. The proposed model is solved by CPLEX optimization software and by a developed genetic algorithm. During this computational analysis, we compare results of proposed pretuned genetic algorithm with a global optimum of CPLEX solver. Then, a sufficient number of large-size instances are generated and solved by the proposed genetic algorithm. To the best of our knowledge, there has been no similar multi-period multi-product closed-loop supply chain design and planning problem utilizing any kind of meta-heuristics let alone genetic algorithms. Therefore, in this issue, it is an original research, and results prove the acceptable performances of the developed genetic algorithm.     

再制造闭环物流网络优化设计模型

为提高再制造物流管理绩效，合理设计再制造物流网络结构，基于混合整数线性规划方法提出一种多产品、有能力限制的再制造闲环物流网络优化设计模型，据此确定网络中各种设施的数量和位置，并在由此构成的各条物流路径上合理分配物流量，目标是使计划期内的净收益最大。通过一个算例验证模型的有效性，并从正向和逆向物流设施的集成、正向和逆向物流运输的整合、回收处理技术的选择等方面讨论模型的进一步扩展。     

闭环物流宏微观协同决策模型

在原有的正向物流基础上,将逆向物流并入其中,构成一个闭环的物流网络。以总闭环物流运输成本、库存成本、惩罚成本和建设成本之和最低为目标,建立闭环物流网络数学规划模型,实现了在闭环物流系统宏观总需求前提下的微观物流计划安排,并利用分支定界法解出其最优解。实例分析结果表明,宏微观协同决策模型较好地补充了传统闭环物流模型的静态单目标单产品问题,可以解决动态多目标多产品的决策问题,实现了供应链设计宏观战略和微观战术的结合。     

A multi-echelon reverse logistics network design for product recovery—a case of truck tire remanufacturing

Due to increasing environmental deterioration, government regulations, social responsibilities, resource reduction, and economic factors, many companies are engaged in the product recovery business. Product recovery refers to the set of activities designed to reclaim value from a product at the end of its useful life. Due to the increasing number of vehicles in the country like India, large quantities of used tires are generated every year, and proper disposal of these used tires creates a significant problem in the day-to-day life. An alternative way to recover the value (tire remanufacturing also called retreading) from the used tire is proposed in this work. The implementation of such remanufacturing system usually requires an appropriate reverse logistics network for choosing the physical locations, facilities, and transportation links to convey the used products from customers to the remanufacturing facility and from there to secondary markets. The main objective of this work is to develop a mixed integer nonlinear programming model for maximizing the profit of a multi-echelon reverse logistics network and also to present a real-life case study of truck tire remanufacturing for the secondary market segment. The proposed model is solved using LINGO 8.0 optimization solver which provides the decisions related to the number of facilities to open, their locations, and also the allocation of the corresponding product flows. Finally, it is concluded that the choice of using retreaded tires is a profitable one by the way of cost reduction. Sensitivity analysis of the model is also presented to find the maximum allowable distance between the customers and initial collection points.     

A proposed mathematical model for closed-loop network configuration based on product life cycle

Products may be returned over their life cycle. Industrial experiences show that there are three main return–recovery pairs. Commercial returns are repaired. End-of-use returns often are remanufactured. In addition, end-of-life returns are recycled. However, up to now, no optimization model is proposed for closed-loop configuration based on three return–recovery pairs. The repaired and remanufactured products can be sold in the same or secondary market. In this paper, we design and configure a general closed-loop supply chain network based on product life cycle. The network includes a manufacturer, collection, repair, disassembly, recycling, and disposal sites. The returned products are collected in a collection site. Commercial returns go to a repair site. End-of-use and end-of-life returns are disassembled. Then, end-of-life returns are recycled. The manufacturer uses recycled and end-of-use parts and new parts to manufacture new products. The new parts are purchased from external suppliers. A mixed-integer linear programming model is proposed to configure the network. The objective is to maximize profit by determining quantity of parts and products in the network. We also extend the model for the condition that the remanufactured products are sent to the secondary market. The mathematical models are validated through computational testing and sensitivity analysis.     

报废汽车零部件回收再利用的价值潜力

汽车产业的发展离不开对资源的索取和利用,然而大部分的车用材料都是有限且不可再生的,因而资源的回收再利用是汽车产品闭环设计必须坚持执行的准则。该研究以乘用汽车的寿命分布函数为依据建立了汽车报废量和零部件回收价值之间的关系。通过对报废汽车零部件的三种主要回收利用方式(零部件再使用、再制造和升级再制造)理论价值模型的建立,形成了报废汽车零部件的回收价值评估体系。并以汽车发动机作为样本零部件,研究结果表明:每回收1000辆小型客车,其发动机的直接再使用(或再制造)价值相当于44台(或21台)新的发动机。     

Lot-streaming policy for forward–reverse logistics with recovery capacity investment

In this paper, we consider the problem where after usage the finished goods are collected at a constant rate and returned to the manufacturer who uses them to produce new products. In order to optimize this kind of closed-loop supply chain, it is necessary to synchronize the forward flow and the reverse flow in establishing the operational policies for both the lot size and the delivery frequency between products consumption and parts recovery. Additionally, the decision regarding recovery policy with lot-streaming policy should be considered deliberately to minimize overall supply chain cost. We develop the optimization model for controlling the lot-streaming policy in the closed-loop logistics scheme and propose the solution procedure for determining the lot-streaming policy and recovery policy. From the sensitivity analyses, we observe that optimal lot-streaming policy and recovery policy could be characterized by either pure strategy or mixed strategy according to the changes in the relevant cost factors. So, an integrated management of both lot-streaming policy and recovery decision could be a critical managerial issue in a closed-loop supply chain.     

零售商主导闭环供应链混合回收渠道选择决策

为研究奖惩机制下零售商主导闭环供应链中各参与主体的回收渠道最优决策问题,运用博弈论建立4种奖惩机制下具有竞争性的双渠道销售和多渠道回收闭环供应链模型,对比分析了4种混合回收模式下供应链成员利润、整个供应链系统的利润和回收水平。研究表明:废旧产品回收价格系数与回收渠道竞争系数之比较小时,制造商会选择制造商和第三方回收商这一混合回收渠道,此时供应链存在不稳定性;反之,制造商会选择制造商、零售商和第三方回收商这一混合回收渠道,此时供应链具有长期稳定性。单位奖惩因子和销售渠道模式不影响供应链各成员的最优回收渠道决策。     

基于回收比例的闭环供应链动力学行为分析

运用系统动力学构建具有普遍适用性的闭环供应链仿真模型,在不同需求条件下设置不同回收比例,研究回收对正向供应链动力学机制的影响,仿真结果显示,闭环供应链动力学行为尽管仍使正向供应链各级成员表现出牛鞭效应,但随着回收比例的增加,牛鞭效应会不断弱化。     

Design of a closed-loop supply chain (CLSC) model using an interactive fuzzy goal programming

A closed-loop supply chain (CLSC) network is composed of both forward and reverse flows. An essential issue to be considered in designing any supply chain network is determination of number and locations of facilities in each layer of the network. Such a problem is a challenging job, since it contains sub-problems which are proven to be nondeterministic polynomial time complete. This paper proposes a CLSC distribution network design problem in which reverse flows are imported into forward model proposed by Selim and Ozkarahan (Int J Adv Manuf Technol 36:401–418, 1). Such a model is considered assuming forward covering (model I) and backward covering (model II) objectives, and then results are compared against the model incorporating covering of both forward and backward networks (model III). Our aim is to accentuate on the role of considering backward parameters in design of a CLSC network and to show how results differ from considering sub-problems separately. To model and solve the problem, a fuzzy goal programming approach is developed for network design in an interactive manner between decision maker and the model. To validate the presented model and the proposed solution approach, a test problem is presented and comparison of results is made using this problem. The results show that the proposed model can solve the CLSC problems in a manageable time. Moreover, outputs of the three models differ significantly. Therefore, the role of incorporating backward flows into the network design problem has been shown using our experiments.     

产品回收模型研究

讨论了废旧产品回收的各种方案和回收过程，提出了产品回收的混合整数规划模型，模型的目标是最大化产品回收过程的净利润。在模型中考虑了产品回收处、加工工厂、回收方案的选择。该模型具有很强的通用性。     

The economics of cell phone reuse and recycling

There is widespread consensus that landfill of waste electronic and electric equipment is not an acceptable end-of-use management option. Diversion from landfill, either through voluntary or mandatory take-back and collection programs, overwhelmingly leads to the recycling of e-waste, which typically consists of the recovery of a limited number of metals. Cell phones are currently one of the few electronic products, if not the only one, that also have a thriving reuse market. In fact, more handsets are reused than recycled. Cell phones therefore offer the rare opportunity to compare closed-loop supply chains for e-waste reuse and recycling. In this paper, we examine the economics of cell phone reuse and recycling based on detailed primary data collected from reverse logistics, reuse and recycling operations in 2003 in the UK and in 2006 in the US. We show that while cell phone reuse has a healthy profit margin, handset recycling is currently a by-product of reuse.     

逆向供应链生产运作研究

针对传统生产模式存在的弊端,结合目前国内外逆向供应链研究的现状,提出了一种集成制造与再制造模式的逆向供应链生产运作模型。研究了再制造的存在条件,分析了组件恢复比率和回收产品平均滞后期对产品最大收益的影响,解决了制造与再制造共存环境下生产计划的制定问题,并通过数值算例验证了模型的可行性和有效性。最后对企业生产提出了具有现实指导意义的建议,展望了逆向供应链生产运作未来的研究方向。     

具有外包选择的闭环供应链切换模型及其鲁棒控制

建立了一类具有外包选择的闭环供应链切换系统模型,包括自行回收再制造和外包两个子系统,以及基于成本的切换信号向量。为了抑制闭环供应链系统在自行回收再制造和外包切换过程中产生的运作波动和牛鞭效应,应用鲁棒控制理论方法给出了供应链切换系统的控制律,分析了闭环供应链切换系统运作过程,并进行了控制律计算和系统仿真,验证了鲁棒控制律的有效性。     

面向再制造闭环供应链的虚拟企业知识管理研究

在引入虚拟企业运作模式的基础上,首先分析了面向再制造闭环供应链的虚拟企业的运作框架,然后从核心层运作与松散层运作的流程和特点出发,对其知识需求深入分析,并以此为依据提出知识框架,构建核心层与松散层的知识管理过程模型,进而从知识资源管理的角度为面向再制造闭环供应链的虚拟企业解决了发展的关键问题,为再制造产业的知识水平提升起到了促进作用。     

A two-echelon inventory model with product returns considering demands dependent return rates

Supply chains usually deal with processing of returned products so that part of the customer demands can be met using the remanufactured products. Therefore, to have an effective inventory management system, it is necessary to consider the effects of the returned products on inventory policy of all involved parties in a supply chain. In this paper, a two-echelon inventory model is developed for a single reusable product in which the return rates explicitly depend on demand streams. The remanufacturing process transforms a returned product to a serviceable one. We extend the basic inventory model incorporating both manufacturing and remanufacturing processes using a continuous review inventory policy. We apply a dynamic programming approach for solving our extended model. To show the applicability of the model, a numerical example is presented. Sensitivity analysis results of the model are consistent with the expected behaviors of our developed model.     

A dynamic multi-commodity inventory and facility location problem in steel supply chain network design

Logistics network design is a major strategic issue due to its impact on the efficiency and responsiveness of the supply chain. This paper focuses on strategic and tactical design of steel supply chain (SSC) networks. Ever-increasing demand for steel products enforces the steel producers to expand their production and storage capacities. The main purpose of the paper includes preparing a countrywide production, inventory, distribution, and capacity expansion plan to design an SSC network. The SSC networks consist of iron ore mines as suppliers, raw steel producer companies as producers, and downstream steel companies as customers. Demand is assumed stochastic with normal distribution and known at the beginning of planning horizon. To achieve the service level of interest, a potential production capacity along with two kinds of safety stocks including emergency and shared safety stocks are suggested by the authors. A mixed integer nonlinear programming (MINLP) model and a mixed integer linear programming (MILP) model are presented to design dynamic multi-commodity SSC networks. To evaluate the performance of the MILP model, a real case of SSC network design is solved. Furthermore, solving two proposed models by using a commercial solver for a set of numerical test cases shows that the MILP model outperforms MINLP in medium- and large-scale problems in terms of computational time. Finally, the complexity of the linear model is investigated by relaxing some major assumptions.     

Coordination of order and production policy in buyer–vendor chain using PROSA Holonic architecture

Supply chain (SC) coordination can be pursued by adopting a centralized or decentralized decision-making approach. In recent years, new software architecture for managing the supply chain at the tactical and operational levels has emerged. It views the supply chain as a set of intelligent software agents, each responsible to perform one or more activities in the supply chain while interacting and negotiating with other agents in the planning and execution of these responsibilities. This paper describes a practical system framework for coordination activities in a buyer–vendor chain to determine the best decision making in the chain using the holonic paradigm. In the present article, while reference is made to the holonic paradigm, its related concepts as well as the implementation aspects of the mentioned paradigm within a supply chain are discussed. Throughout the article, as we try to cast light on the Product-Resource-Order-Staff Architecture of this approach, attention is paid to the operational advancements of the model in order for the model to be responsive to the needs of coordination of product and information flows within a buyer–vendor chain under present stochastic environments. The proposed holonic model in this article makes use of intelligent agents and mathematical models to build decision-making models in the proposed holons, as well as solution algorithms, negotiation mechanisms, and coordination-expanded policies in the mentioned architecture. Numerical studies are also provided to illustrate the effectiveness of the proposed models and methods.     

经销商从事再制造的多期闭环供应链网络均衡*

近年来,在工程机械和建筑设备等行业,出现了经销商从事再制造的实际案例。基于此,研究经销商从事再制造的多周期闭环供应链网络均衡问题。在每个规划期末,经销商承担废旧产品的回收,然后将一部分转卖给制造商,剩余部分用于自身的再制造;此外,考虑制造商能够在设计阶段确定产品的可再制造水平。利用变分不等式和拉格朗日对偶理论获得各层成员的Nash均衡条件,进而建立整个闭环供应链网络的均衡模型。通过修正投影收缩算法求解,结合算例分析经销商的再制造转化率和经销商销售给制造商的废旧品比例对各成员利润和再制造设计水平的影响。结果表明：在大多数情况下,经销商从事再制造对其自身有利,制造商利润降低,需要设计适当的机制实现系统的帕累托改进;随着再制造转化率的提高,经销商的收益逐渐改善,制造商的利润增加缓慢。