考虑多类零售商的库存与运输VMI 集成策略

研究由单批发商多零售商构成的供应商管理库存(VMI)供应链,批发商向外部供应商订货,并为价格和缺货成本不同的零售商补货.首先构造解析模型以分析如何为多类零售商确定不同的库存分配策略;然后将这一最优的库存分配策略与最优的先到先服务(FCFS)策略进行比较,同时比较相应简化的库存分配策略和简化的FCFS策略.解析和算例结果表明,简化的库存分配策略总是优于简化的FCFS策略,而最优的库存分配策略大部分情况下优于最优的FCFS策略.     

基于ACCESS的产品实时库存及质量检验管理系统

为使产品库存和产品质量检验数据管理规范化、便捷化,并且在企业内部局域网实现数据共享,对企业的库存管理方式和产品质检过程进行充分调研,针对中小型机械制造类企业的实际需求,利用Microsoft Access 2003开发了产品实时库存及质量检验管理系统。实践证明,该数据库系统解决了企业旧的台账管理方式中数据处理机械化、低效率问题。     

A note on a production‐inventory model under stock‐dependent demand,Weibull distribution deterioration,and shortage

Recently, Roy and Chaudhuri presented a production‐inventory model for deteriorating items when the demand rate depends on the instantaneous inventory level and the production rate depends on both stock level and demand. The models without shortages and with shortages were discussed. These models impose continuity constraints on the inventory levels, and consequently the optimization problems so obtained are constrained ones. However, the authors treated them as unconstrained ones.     

An optimal policy for a single-vendor and a single-buyer integrated system with setup cost reduction and process-quality improvement

The single-vendor single-buyer integrated production inventory system has been an object of study for a long time, but little is known about the effect of investing in reducing setup cost reduction and process-quality improvement for an integrated inventory system in which the products are sold with free minimal repair warranty. The purpose of this article is to minimise the integrated cost by optimising simultaneously the number of shipments and the shipment quantity, the setup cost, and the process quality. An efficient algorithm procedure is proposed for determining the optimal decision variables. A numerical example is presented to illustrate the results of the proposed models graphically. Sensitivity analysis of the model with respect to key parameters of the system is carried out. The paper shows that the proposed integrated model can result in significant savings in the integrated cost.     

An alternative simple solution algorithm of an inventory model with fixed and variable lead time crash costs under unknown demand distribution

Inventory models with controllable lead time both for known and unknown demand distributions have been proposed in the literature. A model is useless unless it is formulated correctly and feasible. A simple solution procedure of a model also plays an important role in its application. This article highlights an erroneous formulation of an inventory model developed with fixed and variable lead time crash costs under unknown demand distribution, and also demonstrates its infeasibility. To attain feasibility we extend the model to include a constraint. Then, we present an alternative simple solution technique of the modified model and carry out a comparative study on a numerical example to show its potential significance.     

Decomposition schemes and acceleration techniques in application to production–assembly–distribution system design

The purpose of this paper is to study several schemes for applying Dantzig–Wolfe decomposition (DWD) to the production–assembly–distribution system design problem (PADS). Each scheme exploits selected embedded structures. The research objective is to enhance the rate of DWD convergence in application to PADS through formulating a rationale for decomposition by analyzing potential schemes, adopting acceleration techniques, and assessing the impacts of schemes and techniques computationally. Test results provide insights that may be relevant to other applications of DWD.     

An integrated production and inventory model for a system comprising an assembly supply chain and a distribution network

This study investigates the production and inventory problem for a system comprising an assembly supply chain and a distribution network. A uniform lot size is produced uninterruptedly with a single setup at each production stage. Equal-sized batch shipment policy is applied to the whole system and the number of batches can be varied. All retailers have agreed on a joint replenishment policy with a common replenishment cycle. The objective is to determine the optimal common replenishment cycle, the number of batches of each production stage and retailer, all of which minimises the integrated total cost. Moreover, a new concept is introduced; namely, critical replenishment cycle. The replenishment cycle division (RCD) and recursive tightening (RT) methods are then developed to obtain the optimal solutions to the subject problem. Two theorems are verified to ensure the solutions obtained by the RCD and RT methods reaching the global optimum. An example is presented to illustrate the procedures involved in the RCD and RT methods.     

An integrated vendor–buyer inventory model with backorder price discount and effective investment to reduce ordering cost

The single-vendor single-buyer integrated production inventory system has been an object of study for a long time, but little is known about the effect of investing in reducing ordering cost on the integrated inventory models with backorder price discount and variable lead time. The purpose of this article is to investigate in the continuous review model with backorder price discount and variable lead time to effectively increase investment and to reduce the joint expected annual total cost. The integrated strategy discussed here is one in which the buyer orders a quantity, then the vendor produces n times order quantity in each production cycle, in order to reduce setup cost. In addition, the buyer offers backorder price discounts to the customers that may motivate the customers’ desire for backorders, and buyer ordering cost can be reduced through effective investment. An integrated inventory model is established to find the optimal solutions of order quantity, ordering cost, backorder price discount, lead time, and the number of shipments from the vendor to the buyer in one production run, so that the joint expected annual total cost incurred has the minimum value. Furthermore, numerical examples are used to demonstrate the benefits of the model.     

An improved 3D imaging system for dimensional quality inspection of rolled products in the metal industry

Measurement, inspection and quality control in industry have benefited from 3D techniques for imaging and visualization in recent years. The development of machine vision devices at decreased costs, as well as their miniaturization and integration in industrial processes, have accelerated the use of 3D imaging systems in industry. In this paper we describe how to improve the performance of a 3D imaging system for inline dimensional quality inspection of long, flat-rolled metal products manufactured in rolling mills we designed and developed in previous works. Two dimensional characteristics of rolled products are measured by the system: width and flatness. The system is based on active triangulation using a single-line pattern projected onto the surface of the product under inspection for range image acquisition. Taking the system calibration into account the range images are transformed into a calibrated point cloud representing the 3D surface reconstruction of the product. Two approaches to improve the line detection and extraction method used in the original system are discussed, one intended for high-speed processing with lower accuracy, and the other providing high accuracy while incurring higher computational time expenses. A mechanism to remove, or at least reduce, the effects of product movements while manufacturing, such as bouncing and flapping, is also proposed to improve the performance of the system.     

A two‐warehouse inventory model for items with three‐parameter Weibull distribution deterioration,shortages and linear trend in demand

Depending on the type of goods and storage facilities available, perishable goods decay in different manners in terms of the initial point and rate of deterioration. The three‐parameter Weibull distribution is an excellent generalization of exponential decay, with the flexibility of modeling various types of deteriorations. Since inventory management of perishable goods involves expensive storage facilities, the retailer with small storage may have to rent a warehouse. In this paper, we discuss a two‐warehouse inventory model where deteriorations in the two warehouses follow independent three‐parameter Weibull distributions. Transfer of units is from the rented warehouse to the own warehouse, and incurs a positive cost per unit. Demand is a non‐decreasing linear function of time, shortages are backlogged and replenishment is instantaneous. A solution procedure for obtaining optimal values of initial inventory level and cycle time is presented. Sensitivity analysis is carried out. The effect of using other related deterioration distributions is illustrated.     

An operational policy for an integrated inventory system under consignment stock policy with controllable lead time and buyers’ space limitation

This paper aims to enable the decision maker of an integrated vendor–buyer system, under Consignment Stock (CS) policy, to make the optimal/sub-optimal production/replenishment decisions where the buyer places a space limitation to the vendor and the lead-time is controllable with an extra investment. Within any production cycle, the vendor produces at a finite rate and ships the outputs to the buyer with a number of equal-sized lots. With a long-term consignment stock agreement, the vendor takes responsibility to maintain a certain inventory level in the buyer's warehouse. Some of the shipments are delayed so that the buyer's inventory does not go beyond the capacity limitation. The buyer compensates the vendor after the complete consumption of the products. The holding cost consists of a storage component and a financial component. Two constraint four-variable non-linear integer optimization models are established wherein the buyer space limitation is considered. Because the developed models are mathematically very difficult to solve, three doubly hybrid meta-heuristic algorithms are employed to solve the models. The computational results show that one of these three algorithms works very well both in the sense of the success rate and the mean CPU time. The analysis of the computational example also reveals the quantitative effects the buyer space limitation may have to the annual joint total expected cost (JTEC) of the integrated system.     

An intelligent adaptive system for the optimal variable selections of R&D and quality supply chains

The cost of research & development (R&D) and quality management are always regarded as two major parts of total cost. The variable performance of R&D and quality design is an important index that will reflect the effectiveness of the cost reduction. This research has attempted to simultaneously vary all of the variables to achieve the global optimum for the optimal variable selections of R&D and quality design. Genetic algorithm (GA) can treat all of the variables for the global search. In this study, fuzzy refinement with orthogonal arrays was effective in improving the performance of the GA, and also showed the benefits of a good chromosome structure on the behavior of GA. It is also proposed the postponement design with temporal concept, to select the effective variables for the cost reduction of R&D and quality management design. The experimental results showed that tempo-postponement design will increase the flexibility and quick response for supply chain management. Hence, this approach can act as a useful guideline for researchers working on the optimization of the key variable selections for R&D and quality model design.     

Perceived risks, counter-beliefs, and intentions to use anti-/counter-terrorism websites: An exploratory study of government–citizens online interactions in a turbulent environment

This study examines the relationships between various risks, beliefs, and behavioral intentions that are related to citizens' use of anti-/counter-terrorism e-Government websites. The data was collected through two surveys within a one-year interval — before and after the Iraqi regime was expelled by the US coalition army. The results suggest that perceived privacy risk from an anti/counter-terrorism authority is the major obstacle in citizen-to-government anti/counter-terrorism information flow, while citizens' belief in the authority's domain competence greatly influences citizens' dependence on anti/counter-terrorism website information. Other findings and implications are discussed, and directions for future research are suggested.