Title: Inventory Control of WEEE (Waste of Electronic and Electrical Equipment) Reverse Logistics in parts of China  --The HEA (household electrical appliances) manufacturers’ perspective   Background: With economic development, the requirement of public for enterprises and products has become increasingly rational. Price is no longer the only consideration of public, they also pay attention to other factors, such as energy conservation. The manufacturers face enormous challenges because of the late start of products recycling in China. So enterprises start to build their own recycling logistics system in order to have more competitive for themselves.   Purpose: The purpose is to describe the methods of inventory controls in the case HEA manufacturers and the problems of inventory controls, find out what problems exsist in the case manufacturers, then analyze what are the origins of these issues for HEA manufacturers as well as propose how these issues can be alleviated, and what methods would be suitable. By solving these research questions, the thesis tries to offer some suggestions about inventory control improvement not only to the cases, but also wider to the whole HEA manufacturers in China.   Method: Multiple - case study as research method has been applied. Specifically, two case companies, Chinese HEA manufacturers, have been selected. Two telephone focused interviews combined with open-ended interviews have been conducted with two related managers. The empirical evidence has been analyzed by using with-in case study and cross-case analysis method, then model analysis is applied.     Results, conclusion: First, the methods are not good enough in the two case companies, a new model is built to help inventory control in the case companies. Second, from external and internal perspective, the origins to cause the problems are a lot, but the main causes are environmental factors, and in busy seasons of these companies. Besides, for doing reverse logistics is a capital costing job, none of the enterprises would like to step in. and reverse logistics is in an uncertainty environment, doing so need to make sure everything clearly and orderly, or costs will be a large amount. The best way of improving inventory control of WEEE reverse logistics in China is that the enterprises standing together to restore the orders.   Limitations and drawbacks: For one thing, there are not enough previous studies references in China, this brought some difficulties of supporting the view points in the thesis. Two empirical cases are not persuasive enough to represent the whole China due to the limitation of the authors’ knowledge and the huge area of China. Nevertheless, the ideal model in model analysis is not that complicated, which means, for more complex problems and processes, the model would be lame.

I ett litet företag finns en risk att ledningen fokuserar så mycket på kärnverksamheten att övriga administrativa verksamheter åsidosätts. Exempelvis finns det risk att företaget inte har full kontroll på sina lager. Syftet med den här uppsatsen är att beskriva och analysera värderingen och styrningen av lagret hos ett litet handelsföretag med butik och i förekommande fall ge förbättringsförslag. Vi har dels studerat lagar och rekommendationer avseende hantering av lager samt litteratur inom området lagerstyrning i handelsföretag. Dessutom har vi intervjuat företrädare för ett typiskt litet handelsföretag. Det undersökta företaget uppfyller gällande lagar och rekommendationer, men inte så mycket mer. Vidare använder sig företaget mestadels av känsla och erfarenhet i sin lagerstyrning. Förtaget använder alltså inte formella analyser och metoder i någon större utsträckning, om ens någon. Vi har några förslag på förbättringar i detta avseende. / In a small company there is a risk that the management focuses so much on the core business that other administrative tasks are ignored. For example, there is a risk that the company does not control its inventories efficiently. The purpose of this thesis is to describe and analyze the valuing and control of the inventory in a small retail company with a store and, where appropriate, give suggestions for improvement. We have studied laws and recommendations regarding inventory valuation and other literature regarding inventory control in retail companies. Additionally we have interviewed representatives for a typical small retail company. The investigated company does comply with applicable laws and recommendations, but not much more. Furthermore, the company uses mostly feel and experience in its inventory control. The company does not use formal inventory control in any great extent, if any. We have some suggestions for improvements in this regard.

The traditional (Q,r) inventory control model assumes that the date at which the order is entered is the same as the date at which it is requested or expected to be delivered. Hence, the penalty cost is incurred when the customer places the order if inventory is unavailable. This is a reasonable assumption for retail systems and most distribution centers (DC), but not for an assemble-to-order (ATO) environment. In this scenario, there is a delivery time which is usually pre-negotiated and in addition to considering the manufacturing process time and in some cases the outbound transportation time, it also has some safety time built-in. This safety time is defined by the manufacturer and represents information related to when the penalty is incurred. The main objective of this research is to develop a modified (Q,r) policy that incorporates the safety time, and to evaluate this policy in terms of expected inventory cost and expected penalty cost / late orders. The problem is addressed following the heuristic approach discussed by Hadley and Whitin (1963). Two main models are developed based on the following assumptions: 1) early shipments are allowed by the customer, and 2) no early shipments are allowed. The behavior of both models is analyzed mathematically and by means of numerical examples. It is shown that from a manufacturer perspective, the first model is preferred over the traditional (Q,r) model. However, it poses a threat for the long term business relationship with the customer because the service level deteriorates, and for the implications that early shipments have on the customer inventory. The behavior of the second model is strictly related to the problem being addressed. Its merits with respect to the traditional and the "early shipment" model are discussed. This discussion is centered on the coefficient of variation of the lead-time demand, the ratio (IC/pi), and the location of the supplier. A final model which is a hybrid of the previous two shipping policies is developed. The models developed in the course of this research are generalizations of the traditional (Q,r) model.

The telecommunications industry has been in the process of merging. However, the decline of Average Revenue Per User (ARPU) shows the saturation of mobile phone market. At the same time, the Directorate General of Telecommunications (DGT) has announced the implementation of number portability will be in January 2005. Therefore, the resort to sell handsets in high discounts is unavoidable to retain the existing customers and get the new subscribers. Because the high cost, short product lifecycle, diversity of usage, uncertainty of leading time in procurement and indefinite of consumers¡¦ demands, the management of handset inventory has been perplexed the telecommunication industry. This research tries to create an inventory model to provide the mobile phone companies a direction for deciding what the right order quantity is and when the re-order point is. It also can improve the satisfaction of customers and enforce the partnership with vendors. The vendor managed inventory (VMI) which is different from traditional inventory management is taken into consideration, and the target is the high-end function handset. The model will employ the data of average demand in the past few months and the decline curve of market price as the base. The relation of handsets has been created by using the characteristics of classified product. The methodology of time series analysis is used for this research. The construct of this handset inventory model is from the viewpoint of telecommunication industry.

In this study, inventory&ndash / routing system of a company operating in Fast Moving Consumer Goods (FMCG) industry is analyzed. The company has decided to redesign distribution system by locating regional warehouses between production plants and customers. The warehouses in the system are all allowed to hold stock without any capacity restriction. The customers are replenished by the warehouse to which they have been assigned. Customer stocks are continuously monitored by the warehouse and deliveries are to be scheduled. In this multi&ndash / item, two-echelon inventory&ndash / distribution system, main problem is synchronizing inventory and distribution decisions. An integrated Mixed Integer Programming optimization model for inventory and distribution planning is proposed with the aim of optimally coordinating inventory management and vehicle routing. The model determines the replenishment periods of items and amount of delivery to each customer / and constructs the delivery routes with the objective of cost minimization. The integrated model is coded in GAMS and solved by CPLEX. The integrated inventory-routing model is simulated with retrospective data of the company. Computational results on test problems are provided to show the effectiveness of the model developed in terms of the performance measures defined. Moreover, the feasible solution obtained for a period is compared to the realized inventory levels and distribution schedules. Computational results seem to indicate a substantial advantage of the integrated inventory-routing system over the existing distribution system.

Inventory management policies of two independent dealers in a service parts system with transshipment is studied in this thesis. Dealers can collaborate by pooling inventory or service. Revenue is shared in transshipment, can sometimes be contrary to profit maximization of one of the parties albeit sum of profits is increased. To assess the benefits of inventory pooling under equilibrium strategies, and the effect of competition on profits, a Markov Decision Process is formulated. A simpler variant of the optimal four-index threshold policy is used to characterize the production, service and transshipment related inventory decisions. A game theoretical approach as well as notions from policy iteration is taken to find the best response policy and equilibrium policies of the dealers. Numerical study is conducted to investigate the effect of cost, revenue and demand parameters, as well as dealer asymmetricities on benefit of pooling, service levels and transshipment flows. Analysis shows that commission schemes fairly allocating transshipment value to the players, high customer traffic intensities, and low transshipment costs are most suited environments for pooling. System centralization is beneficial when the inventory holding costs are high, transshipment costs are low, customer traffic intensities are high or the commission structure is distracting a party. Competition, within the experimental settings, dampens about 45% of the benefits of pooling.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 122-134). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 122-134). Also available on the Internet.

Sammanfattning Syfte - Syftet med denna studie är att bidra till ökad förståelse för hur lager kan styras när varierad efterfrågan förekommer. För att uppnå syftet är målet med studien att sammanställa processer som underlättar för lagerstyrning vid varierad efterfrågan. Detta möjliggörs genom att besvara följande frågeställningar: 1. Vilka metoder för säkerhetslagerberäkning och lagerstyrning är lämpliga när hänsyn bör tas till varierad efterfrågan? 2. Hur påverkas lagerförings- och ordersärkostnader av olika sätt att styra lager vid varierad efterfrågan? Metod - Teorier angående lagerstyrning vid varierad efterfrågan samlades in via litteraturstudier. En fallstudie genomfördes för att applicera det teoretiska ramverket på empiri från fallföretaget. Empiri samlades in via intervjuer och dokumentationsstudier och utgjorde en grund för beräkningar och vidare analys. Resultat - Lämplig säkerhetslagerberäkning vid varierad efterfrågan anses vara SERV2 som tar hänsyn till antalet bristtillfällen och ger ett bra mått på lagertillgängligheten över tid. De dynamiska lagerstyrningsmetoderna Silver & Meal samt Wagner-Whitin kan i större utsträckning hantera stora variationer i efterfrågan gentemot beställningspunktssystem. Beräkningar resulterade i att Wagner-Whitin var den lagerstyrningsmetod som i majoriteten av fallen genererar lägst totalkostnad när hänsyn tas till lagerförings- och ordersärkostnader. En process för lagerstyrning vid varierad efterfrågan har kartlagts där indata i form av metod- och resursobjekt redogörs. Detta för att bidra till ökad förståelse för hur lager kan styras vid varierad efterfrågan. Implikationer - Inom denna studie framgår det att kostnaderna för lagerstyrningen vid varierad efterfrågan kan sänkas med hjälp av dynamiska lagerstyrningsmetoder. Det är dock viktigt med trovärdig indata för att generera tillförlitliga resultat. Begränsningar - Inom de dynamiska lagerstyrningsmetoderna vägs ordersärkostnad mot lagerföringskostnad och genererar det mest ekonomiska alternativet ur lagerstyrningens perspektiv. Det måste inte vara det bästa ur ett helhetsperspektiv då förändrade orderkvantiteter kan påverka andra delar av materialflödet. De processkartor som är upprättade utgår från den valda lösningen, detta begränsar tillämpningen till verksamheter som har liknande förutsättningar som fallföretaget. Nyckelord - Varierad efterfrågan, lagerstyrning, säkerhetslagerberäkning, lagerstyrningsmetod. / Abstract Purpose - The purpose of this thesis is to develop an understanding of how to control inventory when the demand varies. To achieve the purpose, the goal is to create a process that facilitates inventory management at varied demand. This is feasible by answering following questions: 1. Which methods of safety stock calculation and inventory control are appropriate and take varied demand in consideration? 2. How is the inventory carrying cost and ordering cost affected by different methods of controlling inventory when demand varies? Method - Information about controlling inventory at varied demand was gathered through literature studies. A case study was carried out to apply the theoretical framework on empirical data from the business case. The empirical data was collected through interviews and documentation studies, which provided a basis for calculation and further analysis. Findings - SERV2 is considered as an appropriate method for safety stock calculations since it takes the number of occasions for shortages into account and provides a good measurement of the stock availability over time. The dynamic inventory control methods Silver & Meal and Wagner-Whitin can handle variations in demand better than order point systems. Calculations show that Wagner-Whitin generates the lowest total costs in the majority of cases. A process is established to facilitate inventory management at varied demand. Implications - Within this study it is shown that using dynamic inventory control methods can reduce inventory control costs when demand varies. Nonetheless it is important to have persuasive input to generate reliable results. Limitations - The dynamic inventory control methods balance order cost with inventory carrying costs to find the most economic option from an inventory control perspective. It is not always the best solution from a holistic perspective since changed order quantities can affect other parts of the material flow. The established process charts are based on chosen solution, which limits its application to businesses with similar conditions as the case study. Keywords - Varied demand, inventory control, safety stock calculation, inventory management

Inventory management is today seen as more competitive oriented, process oriented and better integrated into the companies than before. But still do several companies run their inventories according a traditional approach. There is therefore a need for some companies to evaluate their inventory management and adapt the new view. There is also a need to adjust for increased focus on sustainability, previous research calls for strategies and tools that include sustainable parameters without lowering the profitability. The purpose with this study is to assess inventory management principles and purchasing routines related to the acquisition of packaging material in a process industry. The study aims to develop a framework for decision makers in inventory management. This framework will be the basis for a support tool incorporating a relatively simple and easy-to-use user interface. This master thesis is performed as a case study research and uses several data collection methods, such as a literature review, observations, and interviews. The findings from the data collection is used to evaluate which impact inventory management has on a company’s profitability, and which basic parameters that could be included in the support tool. The empirical findings show that Barilla Sweden’s current inventory management match the traditional approach, but also that they strive to become more competitive and process oriented in their management of inventories. There is however some constraints in their working strategy that prevents them from taking the next step. Comparison between Barilla Sweden’s current order size and an economical order quantity (EOQ) and just-in-time (JIT) approach is made. The comparison shows that Barilla Sweden has money to save and warehouse space to release with changed order quantities. Adapting a new inventory management approach require review of uncertainties, such as delivery accuracy and forecast changes. It is also necessary to evaluate supplier relations and internal working strategies. The effect of these parameters on inventory management can be noticed in the support tool. The tool compares total costs, average stock, tied capital, and environmental and social consequences between the EOQ model and JIT. The support tool visualizes drawbacks and benefits with different order sizes and has an easy-to-use interface.