We report on a project with Polaroid Corporation in which we developed a supply chain model to provide decision support for planning production and transportation. Production occurs in Asia to serve world-wide demand. Production planners must determine both the production quantities as well as whether to ship by sea or by air. We develop a model to optimize a static version of this problem and then show how to use this static model in a dynamic setting. We test the model with data from Polaroid and show its effectiveness. / Singapore-MIT Alliance (SMA)

GNT Group is a Nordic/Baltic wholesaler that distributes products in the IT, entertainment and home electronics sector. GNT is facing problems with inaccurate inventory levels which can lead to unnecessarily high inventory carrying costs or lost sales. Currently the decisions about when and how many to order are made somewhat arbitrarily by the responsible personnel. Their decisions are based only on some brief sales history and on experience. GNT wants to develop its ERP system to be able to support the purchaser in these and other related decisions. The purpose of this thesis is to give suggestions to what decisions the ERP system should support and how these decisions can be made. The three main tasks in this thesis are to suggest how to calculate the optimal order quantity, how to calculate the optimal ordering point and how to decide whether it can be profitable to store an article in only one of GNT’s warehouses. The suggested solution is based on a volume value/demand frequency classification which also takes an item’s life cycle characteristics into consideration. For the different classes suitable calculations and decisions are suggested concerning the three main tasks and issues related to them.

Hydraulic fracturing is an important and abundant process in both industrial applications and natural environments. The current work is the first systematic quantitative study of the effect of interaction in and between complex hydraulic fractures at different spatial scales. A mathematical model, based on the boundary collocation method, has been developed. The model has been employed for a typical field case, a highly segmented vein. This vein is well-mapped, and therefore, represents a well constrained example. The computed apertures are compared to the measured apertures. By using the simplest constitutive model, based on an ideal elastic material, and including the effect of interaction between the segments, it was possible to obtain an excellent match at all considered scales. It was also shown that the concept of effective fracture, as currently accepted in the literature, is not always applicable and may lead to unbounded inaccuracy. Unfortunately, in most cases, very little (if any) directly measured data on fracture and material properties is available. An important example of such a weakly constrained case, involving hydraulic fracturing, is diking beneath the seafloor at mid-oceanic ridges. In this study, it is shown that the commonly accepted scenario of a dike propagating from the center of the pressurized magma chamber to the ocean floor is not consistent with conventional fracture mechanics due to the fact that the chamber has the shape of a thin lens. Even at such a large scale (i.e., a kilometer or more), the mechanical principles of elastic interaction appear to be applicable. Since diking is likely to generate a region of high permeability near its margin, in addition to heat, the ongoing hydrothermal activity becomes localized. Our modeling suggests the probable positions of the propagating dikes. Consequently, comparing the observed locations of hydrothermal sites with respect to that of the magma chamber could be useful for constraining the mechanisms of magma lens evolution.

This study is about an integrated procurement and transportation planning system for purchased components of a consumer-durables manufacturer. Due to transportation cost structures and demand characteristics our problem can be classified as a variant of the dynamic-demand joint replenishment problem. The problem is to determine the replenishment policy using the advantages of coordinated transportation of items that will minimize the sum of total inventory holding and tranportation costs over a finite planning horizon. A mathematical model is formulated for purchasing and transportation decisions for the purchased items using the advantage of joint transportation costs. A two-phased solution method is proposed in order to obtain a &ldquo / good solution&rdquo / for the problem. The proposed solution method is compared with the current practice for different problem instances using retrospective data and created data. As a result it is shown that proposed method decrease the total inventory and transportation cost of the system even though the first aggregate problem can not be solved to optimality.

Ericsson AB har en produktionsenhet i Gävle (Sverige), CDC Gävle. Denna enhet är indelad i två fabriker, Skolgången och Avaström. På Skolgången monteras WCDMA radiobasstationer (3G) och på Avaström GSM radiobasstationer (2G). CDC Gävle har idag ett stort returflöde av emballage från inkommande monteringsmaterial. Det förekommer också många störningar i materialförsörjningen till monteringen. CDC Gävle har beslutat att på sikt ska allt material som idag finns på lager befinna sig på hubbar. Syftet med examensarbetet var att undersöka påfyllnaden av monteringsmaterial till linan. Påfyllnad skulle ske direkt mot linan. Resultatet av arbetet blev en teoretisk försörjningsmodell som byggde på att materialet kom från hubbar. Försörjningsmodellen skulle ta hänsyn till nuvarande systemlandskap samt att det skulle ske på ett så kostnads- och utrymmeseffektivt sätt som möjligt. Den skulle också se över problemen med emballage och störningarna i materialflödet. Arbetet skulle besvara följande centrala frågor: • Hur bör materialet fördelas på hubbarna? • Vilka lastbärare är lämpliga vid levereras till linan? • Vilka förändringar kan komma att krävas av befintliga system, arbetsmetodik samt vilka krav ska ställas? • Var och hur bör omplock av material ske? • Hur kommer materialflödet att se ut från hubb till monteringslina? Arbetet har bedrivits genom datainsamling på CDC Gävles olika anläggningar. Det genomfördes även ett flertalet studiebesök för att se hur andra producerande företag arbetade med liknande frågor. Under arbetsgången har det skett kontinuerliga litteraturstudier. Författarna belyste och tog fram ett flertal parametrar som anses avgörande vid utformningen av en ny försörjningsmodell. CDC Gävle måste besluta hur dessa parametrar ska lösas innan en fullständig implementering av hubbar kan börja. Arbetet resulterade i en försörjningsmodell som är generell för både WCDMA och GSM. Arbetet tar också upp hur hubben bör arbeta, vilka funktioner den ska innehålla samt vart den bör lokaliseras. Vidare rekommenderas lämpliga lastbärare och vilka arbetssätt som är lämpliga för CDC Gävle. Ett av de största problemen i arbetet var att ta hänsyn till de speciella materialflödena som CDC Gävle har, detta gällde bl a reklamation och enhetspackade artiklar. Den centrala parametern i hela försörjningsmodellen var frystiden. Frystiden är den tidsperiod från att kunden inte kan ändra sin order till ordern startas på monteringen. Om det inte existerar någon frystid kommer inte hubben hinna plocka fram och leverera det material som CDC Gävle behöver. Författarna bedömer att det finns goda möjligheter att flytta befintliga lager till hubbar. Det bör dock genomföras ett flertal piloter med olika sorters material innan man går vidare. / Ericsson AB has a production unit in Gävle (Sweden), CDC Gävle. The unit is divided into two facilities, Skolgången and Avaström. WCDMA (3G) Radio Base Stations are assembled at Skolgången and GSM (2G) Radio Base Stations are assembled at Avaström. Today CDC Gävle has a major return flow of packing from received assembly material. There also exist several disruptions in the material supply to the assembly. CDC Gävle has decided that in the long term all material, which today is stored in the warehouse, will be stored in hubs. The purpose of the thesis work was to investigate the replenishment of material to the line. Replenishment was to be made directly to line. The result of the thesis work became a theoretical supply model that was based on the material arriving from hubs. The supply model had to consider the present system environment and also be as cost and area efficient as possible. It was also supposed to look at the problems with packing and disruptions within the material flow. The thesis work was to answer the following essential questions: • How should the material be allocated to the hubs? • Which load-carriers are appropriate on delivery to the line? • What changes could be required of the present systems, working methods and also what requirements are to be made? • Where and how should the re-arrangement of material be done? • What will the material flow look like from hub to assembly line? The thesis work has been carried out by the collection of data at CDC Gävle’s different facilities. Several study visits were conducted to see how other producing companies worked with similar questions. During the work process there have been continuous literature studies. The authors elucidated and compiled several parameters, which were considered crucial in the design of a new supply model. CDC Gävle must decide how these parameters will be solved before a full-scale implementation of hubs can begin. The result of the thesis work was a supply model, which is common to both WCDMA and GSM. The thesis work also covers how the hub should work, which functions it will contain and where it should be located. Further, more suitable load-carriers and ways of working for CDC Gävle are recommended. One of the biggest problems was to take into consideration of the special material flows, which CDC Gävle has; amongst those concerned were the claims flow and the unit-packed articles. The essential parameter in the whole supply model was the frozen horizon. The frozen horizon is the time period from when a customer cannot change the order to when the order is started in the assembly. If there is no frozen horizon, the hub will not have enough time to take out and deliver the material, that CDC Gävle need. The authors’ opinion is that there are good possibilities of moving the present warehouse to hubs. However several pilots should be conducted with different kinds of materials before any further step is taken.

No description available.

À l'ère de la mondialisation, l’environnement industriel et économique a subi plusieurs changements majeurs. Les chaînes logistiques sont en train de devenir de plus en plus de complexes réseaux composés de nombreux acteurs qui sont tantôt en concurrence et tantôt coopèrent pour répondre aux incessantes exigences des consommateurs. Dans un tel contexte, les entreprises se sont rapidement rendu compte de la limite du modèle complètement décentralisé où chacune d’entre elles optimise sa propre chaîne logistique indépendamment des autres acteurs. Afin de trouver de nouvelles sources de compétitivité et de faire face à la perpétuelle complexité de l’environnement économique, les entreprises tentent de dépasser la frontière des actions individuelles favorisant les actions coordonnées et centralisées. Désormais, la coopération entre les diverses chaînes logistiques et la formation d’alliances se trouvent au coeur des préoccupations des entreprises. En effet, en mutualisant les moyens logistiques, la coopération permet une meilleure exploitation des ressources et par le biais des actions collectives, elle permet de mieux bénéficier des économies d’échelles conduisant à réduire significativement les coûts et à générer des bénéfices considérables. Toutefois, dans de tels systèmes coopératifs, les acteurs sont indépendants et par ailleurs toujours intéressés en priorité par leurs profits individuels. De ce fait, la coopération soulève deux enjeux essentiels : (1) Quelles sont les alliances qui sont susceptibles de se former ? Et (2), comment partager les bénéfices réalisés sur les différents acteurs coopérants ? Dans cette thèse, nous nous intéressons au phénomène de la coopération dans les chaînes logistiques. Particulièrement, nous posons les précédentes questions dans des chaînes logistiques ou plusieurs firmes peuvent réduire leurs coûts logistiques en optant pour une gestion collective des stocks. Les principaux résultats de cette thèse portent sur l’utilisation des principes de la théorie des jeux coopératifs pour déterminer les alliances les plus profitables ainsi que la portion de profit que chaque firme doit recevoir afin de garder la stabilité des alliances formées. / In the age of outsourcing and globalization, the economic and industrial landscape has seen many radical changes. In such context, supply chains are becoming complex networks of a large number of entities that sometimes compete and sometimes cooperate to fulfill customers’ needs. Standalone supply chains, where each entity makes its decisions so as to maximize its own profits according to its own objectives, often lead to a loss of efficiency and fail to face the complexity of the economic environment they are facing with. Cooperative structures, however, where resources/service facilities are shared and decisions are made to maximize the global profit, prove to be more beneficial and efficient. Consequentially, many companies are fundamentally changing their way of doing business by exceeding the border of standalone and individual actions toward collective actions and cooperative strategies. Therefore, building alliances appears as a successful strategy in modern supply chain networks. In general, cooperation enables a better exploitation of the system’s resources and offers the opportunity to get benefit from large economies of scope, which in turn reduces the total cost/increases the total savings. However, it raises two natural questions that need to be addressed: (1) Which coalitions can be expected to be formed? And, (2) How will the cooperating actors share their total profit? In this Ph.D. dissertation, we tempt to address these questions in retail supply chains where independent retailers coordinate their replenishment from a supplier in order to save on delivery costs. Considering various joint replenishment environments, our principal contribution is to use principles from cooperative game theory to identify the most profitable alliances and to determine the portion of profit that would be allocated to each actor in order to guarantee the stability of the formed alliances.

This dissertation aims to provide models which will help companies make sustainable logistics management and transportation decisions. These models are extensions of the economic lot sizing model with the availability of multiple replenishment modes. The objective of the models is to minimize total replenishment costs and emissions. The study provides applications of these models on contemporary supply chain problems. Initially, the impact of carbon regulatory mechanisms on the replenishment decisions are analyzed for a biomass supply chain under fixed charge replenishment costs. Then, models are extended to consider multiple-setups replenishment costs for age dependent perishable products. For a cost minimization objective, solution algorithms are proposed to solve cases where one, two or multiple replenishment modes are available. Finally, using a bi-objective model, tradeoffs in costs and emissions are analyzed in a perishable product supply chain.

The retail industry is today characterized by downward price pressure, and the increasedcompetition in the industry has led to pressure on profit margins. Purchasing and supply chainmanagement have become areas of increased strategic importance and play a crucial role inthe business performance. This study aims to extend previous literature in these fields byproviding the existing research with an empirical study on how the purchasing strategy canincorporate a total cost perspective of the supply chain.The purpose of this study was to suggest aspects to incorporate in the purchasing strategywith the objective to consider a total cost perspective of the supply chain. This was donethrough conducting an empirical case study at a Swedish middle sized retail company, bycollecting and analyzing both qualitative and quantitative data through interviews, meetingsand internal databases. Challenges that prohibit the case company to apply a total costperspective were identified in the purchasing process and a total cost model was built tovisualize how these affect total costs. Our findings show that there are six challenges thatprohibit the case company to include the total cost perspective in the purchasing process; theinability to reach minimum order quantities (MOQ), production specific requirements, thedifficulty to combine order suggestions on related stock keeping units (SKU), an uneven flowof orders to suppliers, inefficient time supply period and an inability to coordinate transports.Three aspects were identified as root causes for these challenges and suggested to the casecompany to incorporate in their purchasing strategy to enable the management of total costs inthe supply chain. The aspects are flexible time supply periods, internal and externalinformation sharing and coordination of transport. Furthermore, this research also gives anunderstanding of how the formation of the private label assortment fuels the challenges thatprohibit the company to take a total cost perspective.

No description available.