Supply chain management: A just-in-time perspective

Just-in-time (JIT) has been a widely recognized production philosophy alternative since the early 1980s. JIT principles and techniques have been widely adopted in many manufacturing firms. More recently, supply chain management has evolved as a discipline focusing on the design, planning and control of processes linking the initial raw materials to the ultimate consumption of the finished product. Supply chain efficiency is dependent on the efficiencies of the individual manufacturing organizations and the ability to connect along the supply chain. In this paper supply chain management from a JIT perspective is investigated, focusing on the linking mechanisms between successive companies and the collective efficiency of the supply chain.     

A machine-learning approach for a sintering process using a neural network

This paper presents a machine-learning approach using a multi-layered neural network (NN) with application to a sintering process in an iron- and steel-making plant. Our method induces 'operational rules' that determine operational conditions to obtain products that meet a given quality specification. In our application, an operational condition decides the appropriate ranges of chemical composition and heat input to obtain sinter with desirable properties. Our approach consists of two stages. First, backpropagation (BP) training is performed to obtain a NN which decides whether a given condition is appropriate or not. Secondly, from the trained NN, we extract rules which explain what operational conditions are appropriate. In spite of the effective learning capability, a major drawback of a NN is 'unreadability' of the learned knowledge, or the lack of an explanatory capability, which is crucial in the second stage. We developed a rule extraction algorithm which contributes to overcoming this 'unreadability'. The extracted rules are found to agree well with the knowledge in material science.     

Establishing safety stocks for master production schedules

The basic master production scheduling problem assumes that periodic demands are known with certainty. Uncertainty in the forecasts arc typically accommodated afterwards by adding safety stocks to a schedule. Two popular methods for establishing safety stocks are: (1) the constant cycle service level method; and (2) the constant safety stock method. This paper outlines these methods and then develops a third method which results in optimal safety stocks. The paper includes an experimental investigation aimed at comparing performances of the three safety stock methods. The constant safety stock method is shown to perform within one or two per cent of optimal, while the constant cycle service level method performs worse under most conditions. Shorter lead times, variable order interval lengths, and time-dependent forecast errors all adversely affect the performances of the non-optimal methods. An operations manager could use these results to evaluate the appropriateness of the methods for his master production scheduling environment.     

Recurrence relations for single and product moments of order statistics from a generalized half logistic distribution with applications to inference

In this paper, we derive several recurrence relations satisfied by the single and product moments of order statistics from a generalized half logistic distribution. These generalize the corresponding results for the half logistic distribution established by Balakrishnan (1985). The relations established in this paper will enable one to compute the single and product moments of all order statistics for all sample sizes in a simple recursive manner; this may be done for any choice of the shape parameter k. These moments can then be used to determine the best linear unbiased estimators of location and scale parameters from complete as well as Type-I1 censored samples.     

关于社会主要矛盾中需求变化的分析

社会主义初级阶段的主要矛盾仍然是“人民日益增长的物质文化需要同落后的社会生产之间的矛盾”,但“人民日益增长的物质文化需要”的内容和结构已经发生了新的变化,主要表现为公共消费品的匮乏。这一状况严重制约着社会主要矛盾的解决和社会主义发展目标的实现。政府应该从经济发展、民主法制等方面通过一定途径加以解决,以促进社会的全面进步。     

Fusion Product Planning: A Market Offering Perspective*

Devices that integrate multiple functions together are popular in consumer electronic markets. We describe these multifunction devices as fusion products as they fuse together products that traditionally stand alone in the marketplace. In this article, we investigate the manufacturer's fusion product planning decision, adopting a market offering perspective that allows us to address the design and product portfolio decisions simultaneously. The general approach adopted is to develop and analyze a profit‐maximizing model for a single firm that integrates product substitution effects in identifying an optimal market offering. In the general model, we demonstrate that the product design and portfolio decisions are analytically difficult to characterize because the number of possible portfolios can be extremely large. The managerial insight from a stylized all‐in‐one model and numerical analysis is that the manufacturer should, in most cases, select only a subset of fusion and single‐function products to satisfy the market's multidimension needs. This may explain why the function compositions available in certain product markets are limited. In particular, one of the key factors driving the product portfolio decision is the margin associated with the fusion products. If a single all‐in‐one fusion product has relatively high margins, then this product likely dominates the product portfolio. Also, the congruency of the constituent single‐function products is an important factor. When substitution effects are relatively high (i.e., the product set is more congruent), a portfolio containing a smaller number of products is more likely to be optimal.     

The Differential and Contingent Impact of Concurrency on New Product Development Project Performance: A Holistic Examination*

This article comprehensively examines how the four facets of new product development (NPD) concurrency, consisting of process and product concurrency groupings, influence NPD project performance under the five contextual conditions of (i) location of product in family stream, (ii) project size, (iii) stage in the product life cycle, (iv) innovativeness of the product, and (v) predictability of market demand. Using data from a large sample of NPD projects in multiple industries, there is support for this hypothesized four‐faceted structure of concurrency, consisting of process and product concurrency groupings, thereby contributing new knowledge to the concurrency literature. All four facets of concurrency display a contingent impact on NPD project performance, even though individual effects vary according to the specific contextual variable under consideration. In particular, the process concurrency facet of dynamic iterative routines was universally effective across all five contextual variables, while the product concurrency facet of cross‐functional coordination was effective in significantly influencing at least one NPD project measure. This article also reports similar, but less strong, contingency patterns, with respect to the process concurrency facet of the implementation of downstream coordination and the product concurrency facet of the use of computer‐based integrated design tools. Theoretical and practical implications of our results are also offered.     

Managing Product Rollovers

We study the product rollover strategy decision, where a firm decides whether to phase out an old generation of a product to be replaced by a new with either a dual or single roll. Our model considers a final build of the old product and preannouncement of the new, and incorporates dynamic pricing and inventory decisions. We find that the optimal price path closely follows changes in reservation price curves for the two products over time. We also identify the drivers of the rollover strategy decision, finding that lower market risk (faster diffusion, higher market responsiveness to preannouncements) and higher performance improvement for the new generation are associated with the single roll strategy.     

面向产品全生命周期的保证成本预测系统

随着市场竞争日益激烈,产品保证成本预测所依赖的数据需要根据反馈情况不断更新,对产品整个生命周期中的保证成本预测进行集成管理显得十分重要。本文提出了基于网络、集成技术,等一系列预测方法和管理模式的保证成本预测系统,并介绍了其系统架构、实现的关键技术:浏览器技术、中间件技术、数据库技术及其功能实现方式。     

Designing Products for Adaptability: Insights from Four Industrial Cases

Developing products that are more easily adaptable to future requirements can increase their overall value. Product adaptability is largely determined by choices about product architecture, especially modularity. Because it is possible to be too modular and/or inappropriately modular, deciding how and where to be modular in a cost‐effective way is an important managerial decision. In this article, we gather data from four case studies to model effects of firms’ product architecture decisions at the component level. We optimize an architecture adaptability value (AAV) measure that accounts for both the benefits of more architecture options and the costs of interfaces. The optimal architecture prompted each firm to rearchitect an existing product to increase its expected future profitability. Several insights emerged from the case evidence during this research. (i) Although decomposing an architecture into an increasing number of modules increases product adaptability, the amount of modularity is an insufficient predictor of the adaptability value of a system. AAV, which also accounts for interface costs, provides an improved measure of appropriate modularity. (ii) Managers can influence the path of architectural evolution in the direction of increased value. This influence may diminish but does not disappear as products become more mature. Also, modularity and innovations coevolved, as the new modularizations suggested by AAV optimization prompted and guided searches for further innovations. (iii) When presented with the concepts of options, interface costs, and AAV, the firms’ designers and managers were initially skeptical. However, in each case, the modelers were able to rearchitect an actual product not only with increased AAV by our model (theoretical improvement) but also with actual future benefits for their firm. Postproject reports from each firm confirmed that the AAV modeling and optimization approaches were indeed helpful, equipping them to increase the adaptability, cost‐efficiency, lifespan, and overall value of actual products. The evidence suggests that firms can benefit from designing products for adaptability, but that how they do so matters. This study expands our understanding of modularity and adaptability by illuminating managerial decisions and insights about appropriate approaches to each.