Bringing order [replenishment process control]

The importance of replenishment management in "make to stock" businesses is often overlooked in demand management studies in favour of forecast management. The real issue in replenishment strategy is addressing the fundamental challenge between holding enough inventory to protect future sales versus reducing inventory to reduce costs and enhance productivity. It is likely that replenishment lead-time will be greater than is desirable, vendors will be unreliable and forecasts will in most cases be wrong. Thus, in this paper, the author urges manufacturers to take control of the replenishment process.     

多品种联合补充库存策略综述

为了系统总结多品种物品环境下联合补充问题的研究历史和现状,在相关资料的基础上,对联合补充问题中确定型策略和随机型策略的模型和算法等问题进行了综述,分析了这些研究的特点与不足。对该领域的发展历史进行了简述。分别针对确定型策略的间接分组策略和随机型联合补充策略进行综述。讨论了策略形式间的比较问题,提出了联合补充库存理论研究的方向和重点。     

Maintaining profitable assets [plant maintenance]

The introduction of the climate change levy and pollution prevention and control legislation has placed a greater emphasis on plant maintenance. With pressure to ensure optimum performance and efficiency from all plant assets coming from every side-economic, environmental and political, the author looks at the services and technology available to help.     

Maintaining quality lead-free [circuit board inspection]

The change to lead-free solders means that circuit board inspection will become more important than ever. The author investigates differences between lead and lead-free solders.     

Optimal replenishment policies for deteriorating control wafers inventory

This paper considers a control wafers replenishment problem with inventory deterioration. In the process, control wafers begin to deteriorate after the pre-disposition. The objective of this research is to minimize the total cost of control wafers, where the cost includes ordering cost, holding cost and purchase cost. We first formulate the control wafers inventory problem as a dynamic programming model. We then transform the control wafers’ inventory problem into the mixed 0–1 linear programming model. An illustrative example with four cases is used to illustrate the practicality of these models, and sensitivity analysis is applied to understand the impact of parameters to these models. The results demonstrate that the proposed mixed 0–1 linear programming model is an effective tool for determining the replenishment of control wafers for multi-periods.     

The book that changed the world [inventory control]

The author refers to the books titled “The machine that changed the world” by Womack-Jones-Roos and the follow-up publication “Lean thinking” by Womack-Jones, and explains why a single management book has had a major impact on the thinking of almost every manufacturing company in the Western world. The book is a landmark publication in our understanding of the evolution of lean-production concepts that has taken place in Japanese supply chains     

Scheduling and replenishment plan for an integrated deteriorating inventory model with stock-dependent selling rate

An integrated approach is used to clarify the critical issues of scheduling and replenishment planning in an advanced inventory system under stock-dependent selling rate environment. This is because integration removes the barriers between enterprises and improves overall performance. A close collaboration such as just-in-time (JIT) operations also improves product quality of the supply chain. Different from the single-stage inventory model, this study develops an integrated two-stage production-inventory deteriorating model for the buyer and the supplier with stock-dependent selling rate, as well as considering imperfect items and JIT multiple deliveries. Our paper proposes a significant method using a time-weighted-inventory approach to analyze the supplier’s saw-tooth holding cost. We derive the optimal number of inspection, optimal deliveries and the optimal delivery-time interval. A numerical example is also presented to illustrate the theory. The results show that the fixed demand rate, the holding cost and the unit inspection cost are critical in the management of the deteriorating inventory model.     

A heuristic technique for inventory replenishment policy with increasing demand pattern and shortage allowance

In the growth stage of a product life cycle, the demand rate is usually unstable and follows an increasing pattern. The traditional inventory policies, which have been developed for stationary demand pattern, are not appropriate to this situation. Although there exist some researches in the past dealing with inventory policy for the case of increasing demand pattern, most of them focused on the inventory systems in which shortages are not allowed. In reality, the presence of shortages is sometimes economically preferable when holding cost is significant as compared with shortage cost. The aim of the research presented in this paper is, therefore, to develop a replenishment policy for inventory systems with nonlinear increasing demand pattern and shortage allowance in such a way that the total demand during a predefined planning horizon can be exactly met. A heuristic technique to help determine the operational parameters for the inventory policy is then developed. In the proposed heuristic technique, the consecutive improvement method developed by Wang (Comput Oper Res, 29:1819–1825, 2002) will first be used to help determine replenishment times. And then, a new concept of reduction cost, which is defined as the difference between the holding cost when shortage is allowed and the incurred shortage cost, is introduced and applied to help find the optimal shortage starting point in each replenishment cycle. Numerical experiments are also conducted to illustrate the applicability of the proposed technique.     

A genetic algorithm to optimize multiproduct multiconstraint inventory control systems with stochastic replenishment intervals and discount

There are two main assumptions in multiperiodic inventory control problems. The first is the continuous review, where, depending on the inventory level, orders can happen at any time, and the other is the periodic review, where orders can only happen at the beginning of each period. In this paper, these assumptions are relaxed, and the periods between two replenishments are assumed independent and identically distributed random variables. Furthermore, the decision variables are assumed integer-type and that there are two kinds of space and budget constraints. The incremental discounts to purchase products are considered, and a combination of backorder and lost sales are taken into account for the shortages. The model of this problem is shown to be a mixed integer-nonlinear programming type, and in order to solve it, both genetic algorithm and simulated annealing approaches are employed. At the end, two numerical examples are given to demonstrate the applicability of the proposed methodologies in which genetic algorithm method performs better than simulated annealing in terms of objective function values.     

Defying the market [STMicroelectronics]

In a market suffering a seemingly perpetual downturn, STMicroelectronics is outperforming its competitors. The diversity of its product lines, technologies, alliances and customer base is reckoned to be a strength for ST, but it means that the group often finds itself managing and anticipating the needs of a complex network of internal and external relationships. The article examines the company's success.     

Connected [e-commerce]

Recent years have seen a rapid expansion in the use of the Internet for social and commercial purposes. The author outlines some of the main changes and business issues that the connected company may expect to face. The author takes the view that the new technology should be seen for what it is: another communications channel, not a universal panacea for boosting economic activity. The most likely outcome may be that the Internet supplements the existing communications technologies (e.g. mail, telephone, fax, e-mail and radio) rather than making one or more of them obsolete (remember the `paperless office'?). With that view in mind, the article presents a discussion of what some companies have been able to achieve with the Internet and what may be achievable in the near future     

Leaping the barrier [information technology]

The role of information technology (IT) in manufacturing and engineering is now well understood. It is difficult to imagine a factory, warehouse or drawing office today that could even function without the right IT system. Yet IT has come much further now than just automating manual manufacturing and engineering processes. There are whole new fields of advantage to be gained from squeezing more out of IT systems, particularly by making better use of the information that is stored within them. Overall, technologies such as forecasting tools, data warehousing and workflow can help manufacturers to reduce the level of disconnection in the organisation between different functions and departments. The key is to ensure that as much corporate information as possible is held in a single, digital format, whether as data, test, graphics or knowledge     

Using the system [manufacturing software]

Software implementations tend to be so complex that their delivery becomes an end in itself; not just another investment. The author looks at an approach that keeps the organisation's eyes firmly focused on the business benefits     

Orchestrating the Airbus [project management]

The paper reports on the task of managing the interrelationships and interdependencies between a set of projects supporting different parts of the British Aerospace Airbus design and manufacturing process. The programme office manager monitors progress across 60 live plans to ensure not only that they stay on time and within budget, but that they all deliver optimum business benefits. A continuous improvement programme has been adopted to constantly reassess the project progress against a changing environment     

Making the millennium [factory 2000]

Looks at the roles of technology and management in building a factory that will be competitive in world markets into the next century     

Mind the gap [transistor costs]

The cost of testing each transistor on a chip in 2000 was less than a hundredth of its manufacturing cost. But, within ten years, test costs could have increased and manufacturing costs fallen to the point where the two cross over.     

Breaking the boundaries [embedded testing]

Embedded testing and design for embedded test, are key issues for telecomms manufacturers. The author outlines some recent developments in the field of boundary scan and embedded testing.