Life cycle implications of product modular architectures in closed-loop supply chains

Most of the product life cycle costs and environmental impacts are determined during product design stage. A product supply chain network can be seen as a system dealing with product life cycle processes. Ideally, a product should be designed to have a structure yielding a good life cycle performance in its existing supply chain network. However, there is a lack of research related to modeling supply chain effects in the product design stage. This paper aims at investigating the supply chain effects on product modular design. The life cycle performance of a modular structure (life cycle cost and life cycle environmental impact) at various supply chain states is evaluated by a supply chain evaluation model and analyzed by statistical techniques. The preliminary results indicate that the supply chain-related effects on product life cycle performance are significant and modular structure optimization is effective in reducing the surge of life cycle cost and life cycle environmental impact caused by various supply chain states. The main supply chain effects are identified for use in product design improvement.     

基于拉格朗日松弛和遗传算法的供应链协同计划

研究了多级供应链伙伴间的生产计划协调优化问题。对集成性多阶段约束生产批量计划模型增加了关联约束和相关需求约束。基于模型的加可分性结构,利用拉格朗日松弛技术将其分解为成员独立的子问题。应用遗传算法更新拉格朗日乘子来协调成员决策,在不干涉成员决策权和私有信息的前提下,实现了多级供应链生产计划的协调优化。仿真实验证明了基于拉格朗日松弛技术与遗传算法的计划协同模式和协调方法的优越性和鲁棒性。     

一种面向产品族设计的模块动态规划方法

针对产品族设计中的模块规划问题,研究和分析了产品族核心系统的模块化理论和实施方法,对产品生命周期中的各种动态要素进行了分析;根据核心系统零部件成本等市场因素的动态变化对模块规划的影响,从可维护性和经济性考虑,提出一种产品族核心系统模块动态规划方法;通过建立功能关联矩阵和动态关联权重矩阵,采用模糊聚类方法对功能关联矩阵中的组件进行聚类,通过取适当的α截集,将产品族中的核心系统划分为多个子功能模块,结合动态关联权重分析对模块部件进行动态评价,并提取出动态评价值较高的部件,为设计阶段重点考虑这些部件提供了理论依据,减少了后期维护成本.通过装载机液压传动系统的模块规划和后期维护数据,证明了该方法的可行性.     

无线通讯技术在铁路车号自动识别系统中的应用原理及存在问题分析

介绍了GSM、GPRS、CDMA传输方式在铁路车号自动识别系统(ATIS)中的应用及应用中存在的问题。通过比较,认定GPRS目前最适合车号自动识别系统,并对移动公司与厂家提出一些具体要求。     

A computer-integrated FMEA for dynamic supply chains in a flexible-based environment

Quality management (QM) for dynamic supply chains (DSCs) in a flexible-based environment has received increasing attention in current business environment. This study focuses on the development of an QM tool, based on the failure modes and effects analysis (FMEA) approach, and demonstrates how it can be extended from application in supply chain management (SCM) to other business environments. The main contributions are to implement an iterative process using FMEA for DSCs in a flexible-based environment by overcoming the weaknesses associated with traditional FMEA system and to develop a user-friendly interface, with which the distributed parties in chains could cooperate as a whole and meet the needs of dynamic control. In specific, this paper proposes a computer-integrated FMEA approach that enhanced FMEA in SCM through automated processing using a fuzzy approach and a computer-integrated and internet-based interface to support the system implementation. The efficiency and practical implication of the proposed system has been validated by the developed system with a case study. The developed system can help prevent possible failures in the design and operations and, furthermore, the assurance of quality for DSCs in a flexible-based environment. The proposed system may easily be extended to more complex real-world applications.     

Constraint ratio in product assembly planning

Assembly planning considers the product, process, and production system. The existence of constraints makes the assembly planning process difficult and time consuming. The planning degree of freedom (PDOF) for designers will be increased if the number of constraints is decreased on either the product or the other sides. A higher PDOF means that companies can be more flexible in responding rapidly to the assembly of parts. In this paper, a constraint ratio (C_R) has been defined to measure the influence of the product constraints on assembly planning. Some rules have been established to simplify the evaluation procedures of the constraint ratio of the product. Examples are illustrated and explained.     

钢铁工业三级供应链协调生产计划研究

为了研究矿山、选矿厂和炼铁厂所构成的钢铁工业三级供应链中的协调生产计划问题，建立了相应的混合整数非线性规划模型。该模型的特点是：①集成3个环节的生产计划；②集成生产与运输计划。针对该模型的特殊结构，提出了一种将原问题转化为等价的多个线性规划问题，然后使用Excel标准线性规划程序求解的策略。最后，通过案例说明了模型的有效性，并探讨了进一步研究的方向。     

指数需求下考虑绝对公平关切的供应链定价模型

为研究公平关切对供应链定价决策的影响,在由单制造商和单零售商组成的两级供应链中考虑成员的绝对公平关切,即供应链成员在关注自身获得的经济收益的同时也关注供应链的总利润在各成员之间划分的比例是否公平.假定市场需求为指数函数形式,制造商和零售商之间是Stackelberg博弈,分别分析了零售商和制造商考虑绝对公平关切时的供应链最优定价决策.研究表明,在两种情形下制造商都不能使用批发价契约实现供应链的渠道协调;在一定条件下零售商的绝对公平关切可以减轻双重边际化效应,并且任何时候都不会加重双重边际化效应;而制造商的绝对公平关切则既可能减轻也可能加重双重边际化效应.     

Inventory replenishment and delivery planning in a two-level supply chain with compound Poisson demands

This paper presents a model for integrating inventory replenishment and delivery planning in a two-level supply chain consisting of a supplier and a retailer. The supplier is authorized to manage the inventory level of the retailer by using the information on demands from final customers and the inventory level of the retailer. The problem considered here is to determine order-up-to levels of the supplier and the retailer simultaneously for the objective of minimizing the expected long-run average cost, which is composed of replenishment cost at the supplier, delivery cost to the retailer, and inventory holding costs at both members. We develop a renewal theoretic optimization model for a case of compound Poisson demands with distribution-free order quantities and present an approximation method for obtaining a solution of the problem. In addition, a closed-form solution is derived for the problem with a special case of compound Poisson demands, in which demand quantities follow an exponential distribution. A series of simulation tests show that the solutions obtained from the approximated cost functions are reasonably good.     

基于三维产品模型的装配顺序规划实现技术研究

针对割集法装配序列自动生成存在的问题,以三维产品模型为基础,建立了基于三维产品模型的装配顺序系统结构,对其中涉及的最小生成树的获取、割集法装配序列自动生成、装配信息建模等关键技术进行了研究.在此基础上,以车床刀架为例.对以上技术进行了实现.     

现代产品开发中的概要工艺规划研究

根据产品设计和工艺设计活动的并行效果和产品信息变化规律,提出了初始工艺规划、粗略工艺规划和详细工艺规划3阶段的工艺设计模型。提出了基于关键特性表示粗粒度的非完备产品信息,并建立了概要工艺规划的策略框架。对概要工艺规划的关键技术,即基于关键特性的产品信息识别、具有多级分辨率的制造工艺分类与选择、具有可扩展性的核心工艺设计和基于差异度的可生产性评价,提出了解决方案。     

A measure of the bullwhip effect in supply chains with stochastic lead time

In this paper, we exactly quantify the bullwhip effect, the variance amplification in replenishment orders, for cases of stochastic demand and stochastic lead time in a simple two-stage supply chain with one supplier and one retailer. In most of the previous research, the impact of order lead time on the bullwhip effect in supply chains with pre-specified demand processes is investigated mostly for cases of deterministic lead time. In this paper, we deal with a first-order autoregressive, AR(1), demand process and investigate the behavior of a measure for the bullwhip effect with respect to autoregressive coefficient and stochastic order lead time. Extension to a mixed first-order autoregressive-moving average, ARMA(1,1), demand process is also considered.     

Hybrid approach to distribution planning reflecting a stochastic supply chain

Today’s business environment is experiencing as a period of expansion and the globalization. Therefore, a distribution plan with low cost and high customer satisfaction in supply chain management (SCM) has been widely investigated. The purpose of this study is to establish optimal distribution planning in the supply chain. In this paper, a hybrid approach involving a genetic algorithm (GA) and simulation is presented to solve this problem. The GA is employed in order to quickly generate feasible distribution sequences. Considering uncertain factors such as queuing, breakdowns and repairing time in the supply chain, the simulation is used to minimize completion time for the distribution plan. The computational results for an example of a simple supply chain are given and discussed to validate the proposed approach. We obtained a more realistic distribution plan with optimal completion time by performing the iterative hybrid GA simulation procedure which reflects the stochastic nature of supply chains.     

A view-based approach to modeling product semantics in design chains

To reduce “time-to-market”, semantics of a product must be synchronized in a design chain, because inconsistencies during collaborative product development cause an unnecessary waste of time. To guarantee semantic synchronization, all enterprises should co-operate and maintain semantics whenever they are updated. In this paper, a V2-model is proposed to share product semantics during collaborative product development through view-based semantic synchronization. The V2-model has two kinds of model layers for semantic synchronization: a view-independent model (VIM) layer and a view-specific model (VSM) layer. Semantics in the VIM is the well-structured semantics shared among all enterprises and thus are published across the collaborative design chain. On the other hand, semantics in the VSM is the inconsistent semantics for product information that occurs during the early design stage, when different enterprises may have differing views about product concepts that are constructs of semantics. The inconsistencies between the different views can be solved by a decision and sharing (DnS) process and V2-model. The DnS process transforms the concepts in the VSM to the concepts in the VIM by utilizing topic maps-based scoping and merging functions. The proposed V2-model has been successfully applied to the design process of a washing machine model.     

用遗传算法实现产品回收中的拆卸序列规划

拆卸是产品回收利用中的一个重要环节,拆卸规划的目的是找到最优的顺序,以使拆卸代价最小或者代价效益比最低。这里使用遗传算法来规划拆卸序列,产生满足约束条件的效率最好的顺序。最后算法在一个实际装配体上得到了验证。     

分散决策供应链生产计划协同研究

为解决多级、多产品、分散供应链系统生产计划协同问题,提出了一种基于拉格朗日松弛算法的生产计划协同模型.在该模型中,建立每个企业独立的生产计划模型,使用拉格朗日松弛算法,松弛掉企业之间的物流平衡约束,将需要集中决策的供应链生产计划协同问题,分解为企业间分散的独立决策问题;运用次梯度算法对拉格朗日因子进行更新,通过反复迭代的优化过程实现生产计划协同.仿真实验表明,基于拉格朗日松弛算法的供应链协同对复杂供应链系统能够较好地逼近最优解,协同效果和收敛速度优于遗传算法.     

Threshold-based identification of wireless SAW RFID-tags with pulse position encoding

In recent decades, there have been designed and developed passive surface acoustic wave radio frequency identification tags with time position encoding in groups of slots. For such tags identified when the received pulse-burst exceeds a threshold, we specify the generic identification (ID) error probability and optimize the threshold employing the Marcum Q-function of first order. As examples, we estimate the ID errors for the one-group 28-slot tag and Barker encoding. It is shown that, under the ideal conditions of equal SNRs (14.8 dB) in On-pulses and zeroth in Off-pulses, the ID error probability lesser 1% (one slip per 100 readings) can be guarantied with single reading for any reasonable number of slots. It becomes lesser 0.1% (1 slip per 1000 readings) with seven or lesser slots.     

Evaluation of supply chain structures using a delayed product differentiation process

In this paper, we consider a two-level supply chain consisting of a retailer and n “non-identical” customers. The retailer orders different perishable products in response to the demands of the customers. The unsatisfied demand at a retailer is partially backlogged with a time-proportional backlogging rate. We formulate models for a postponement system and an independent system to minimize the total average cost function per unit time for ordering and keeping n “non-instantaneous deteriorating items.” An algorithm is given to derive the optimal solutions of the proposed models. The impact of the deterioration rate on the inventory replenishment policies is studied with the help of both theoretical and numerical results.     

产品开发中的多软件联合仿真技术

多学科联合仿真需要控制、机构、有限元等不同仿真环境的集成和数据交换.从当前产品设计过程对多学科联合仿真的需求出发,介绍了一种运用多种软件联合仿真开发产品的新思路,通过对CAD,CAE及CAT技术的集成从而达到缩短产品开发周期提高产品质量的目的.