The most costly and labor-intensive activity for almost every warehouse is the order picking process and a key challenge for manufacturing companies is to store parts in an efficient way. Therefore, to minimize the order retrieval time when picking from a storage, the need of a sufficient storage categorization strategy becomes vital. One of the logistics centers at Scania in Södertälje stores parts that will be transported to the chassis assembly and the assembly of gearboxes and axles when needed in the production. In one of the storage areas at the logistics center, namely the PS storage, the forklift drivers picking from the storage have experienced congestion in the storage aisles and that it might be possible to reduce the order fulfillment time when picking the orders. This master thesis aims to investigate the possibility of optimizing the picking process in the PS storage, with respect to the order fulfillment time for the forklift drivers, with categorization of the goods. This has been analyzed with a heuristic optimization approach and with the use of a discrete event simulation model, where different categorization strategies have been applied on the storage and compared to the current state. By categorizing the goods in the PS storage, a reduction of the order fulfillment time can be done of around 4% - 5% compared to the current state with all tested categorization strategies. The strategy which has been shown to give the largest improvement is by categorizing the parts in the storage according to their final delivery address at the production line, which would reduce the order fulfillment time by 5.03% compared to the current state. With this categorization method, parts that are picked on the same route are located close to each other.

Much research has been undertaken to gain insight into business alignment of IT. This alignment basically aims to improve a firm’s performance by an improved harmonization of the business function and the IT function within a firm. The thesis discusses previous approaches and constructs an overall framework, which a potential approach needs to fit in. Being in a highly regulated industry, for airports there is little space left to increase revenues. However, the retailing business has proven to be an area that may contribute towards higher income for airport operators. Consequently, airport management should focus on supporting this business segment. Nevertheless, it needs to be taken into account that smooth airport operations are a precondition for successful retailing business at an airport. Applying the concept of information intensity, the processes of gate allocation and airport retailing have been determined to appraise the potential that may be realized upon (improved) synchronization of the two. It has been found that the lever is largest in the planning phase (i.e. prior to operations), and thus support by means of information technology (for information distribution and improved planning) may help to enable an improved overall retail performance. In order to determine potential variables, which might influence the output, a process decomposition has been conducted along with the development of an appropriate information model. The derived research model has been tested in different scenarios. For this purpose an adequate gate allocation algorithm has been developed and implemented in a purposewritten piece of software. To calibrate the model, actual data (several hundred thousand data items from Frankfurt Airport) from two flight plan seasons has been used. Key findings: The results show that under the conditions described it seems feasible to increase retail sales in the magnitude of 9% to 21%. The most influential factors (besides the constraining rule set and a retail area’s specific performance) proved to be a flight’s minimum and maximum time at a gate as well as its buffer time at gate. However, as some of the preconditions may not be accepted by airport management or national regulators, the results may be taken as an indication for cost incurred, in case the suggested approach is not considered. The transferability to other airport business models and limitations of the research approach are discussed at the end along with suggestions for future areas of research.

Thesis is based on original self-made application programmed at VBA in MS Excel 2007. The reason to build this application was integration of simulation Monte Carlo and chosen optimization methods. The application allows do simulation of the knapsack problem and of the assignment problem with uncertainty. The parameters of these models are possible to set up as changing values in dependence of chosen probability distribution. Output of the simulation is a probability recommendation which objects should be used. Choose of objects depend on optimized models. Results of both models are represented by statistical indexes, tables of parameters and graph.

I model foreign trade among European countries by applying gravity equation model on panel data. The aim is to investigate exchange rate volatility impact on foreign trade and to test for the presence of the so-called Rose effect in relation to the Euro currency area. I develop a novel complex approach to the estimation of the gravity equation when the assumption of homogeneous reaction within the group of studied countries is relaxed. New methodology, tests and implementation is proposed. I develop several heuristic methods that permit effective clustering of countries in a selection of subgroups. The clustering process is iterative: in each step, countries are redistributed in new subgroups and the process is terminated, when no subsequent superior redistribution is possible. Finally, the effective selection of subgroups of countries is chosen to minimize an appropriately defined objective function. Results of the proposed heuristic tests suggest that no dominant method exists. Therefore, an algorithm of chaining of alternative heuristic methods is proposed. After the solution is achieved with one method, an alternative method is imposed and the search for the optimal solution continues, until the objective function reaches its minimum. The proposed methodology is applied to estimate the gravity equation of foreign trade with the extension that permits to assign countries into optimally selected subgroups using the newly introduced algorithms.

The subject of the thesis is the optimization of one the key processes in a book company, namely warehouse logistics. This problem consist of two parts; first part focuses on route optimization of completion of customers' orders on daily basis, second part focuses on assigning of storage subsystems and their interconnection. The proposed solution uses a traveller salesman problem implemented into intranet application. Second problem was designed as quadratic assignment problem with use of ex post data analysis. On the basis of achieved results, we presented effective procedures for solving both of aforementioned problems and suggested their implementation into the company's enterprise resource planning system. Keywords:

Le travail que nous présentons dans cette thèse porte sur le problème d'affectation dans une place de marché de prospects Internet. Plus précisément, ce travail a pour ambition de répondre à la problématique de l'adéquation de l'offre et de la demande, dans un contexte caractérisé par des flux continus faisant évoluer en temps réel l'ensemble des offres disponibles et les demandes à satisfaire. Pour ce faire, nous proposons dans un premier temps un modèle mono-période qui optimise le problème d'affectation à un instant donné et en considérant une seule période de temps, tout en permettant la prise en compte instantanée des nouvelles offres et demandes et leur adéquation en temps réel. Ce modèle permet d'optimiser deux objectifs à savoir: la maximisation du chiffre d'affaires et la satisfaction des clients.Par la suite nous proposons d'étendre ce modèle sur plusieurs périodes de temps futures afin de prendre en compte l'aspect temps réel de l'activité de la place de marché et donc le fait que des flux continus font évoluer en temps réel l'ensemble des offres et des demandes. L'objectif étant de tirer profit de la connaissance concernant cette évolution, par le biais de l'intégration d'un modèle de prévision dans un modèle d'optimisation multi-période.Ainsi, nous proposons un modèle d'optimisation multi-période permettant d'envisager à un instant donné des affectations sur plusieurs périodes de temps futures afin de réaliser les meilleures affectations possibles. Aussi, nous proposons un modèle de prévision des nouveaux flux tout en considérant les caractéristiques du modèle d'optimisation multi-période.Construire un modèle de prévision nécessite de définir les données à prévoir avant d'envisager toute méthode de prévision. En d'autres termes, nous devons choisir les paramètres du modèle de prévision, à savoir: les données historiques appropriées, le pas de temps de la prévision ainsi que l'horizon de la prévision. Le défi consiste donc à définir les paramètres du modèle de prévision qui conviendront au fonctionnement du modèle de l'optimisation multi-période.Par ailleurs, une des caractéristiques de la place de marché est la temporalité de son système. Ainsi, nous proposons un algorithme assurant l'aspect temps réel et donc le fait que les affectations s'effectuent toutes les minutes. L'algorithme que nous proposons fonctionne de manière continue à longueur de journée en optimisant à chaque instant l'adéquation offre/demande de prospects Internet tout en considérant instantanément les flux continus de prospects Internet ainsi que la mise à jour régulière de la demande Enfin, pour mettre en évidence l'efficacité et les bénéfices que la place de marché peut en tirer par l'utilisation des modèles et de l'algorithme proposés, nous avons mené des tests et différentes expérimentations sur des données réelles. Ces tests nous ont permis de valider nos travaux et d'évaluer la qualité des résultats obtenus.L'objectif de ce travail est double, d'une part, donner un cadre solide et formel pour répondre à la problématique de la place de marché de prospects Internet. D'autre part, le cadre proposé devrait être aussi générique que possible afin de résoudre tout autre problème analogue à celui de la place de marché de prospects Internet. / The work that we present in this thesis focuses on the assignment problem in a marketplace of Internet prospects. More precisely, this work aims to address the problem of matching offers and demands in a context characterized by a continuous flows. These latter evolve inreal time the set of available offers and demands to satisfy. To do this, we propose initially a mono-period model which optimizes the assignment problem at a given instant and taking into account asingle period of time while allowing the instantaneous consideration of new offers and demands and their adequacy in real time. This model considers two objectives to optimize, namely: maximization of turnover as well as clients satisfaction.Thereafter, we propose to extend this model over several future time periods in order to take into account the real time aspect of the marketplace activity and so the fact that a continuous flows evolve in real time the set of offers en demands. The objective is to take advantage of knowledge about this evolution, through the integration of a forecasting model in a multi-period optimization model. Thus,we propose a multi-period optimization model for considering at agiven instant assignments over several future time periods. Also, we propose a forecasting model for new flows while considering the characteristics of the multi-period optimization model.Building a forecasting model requires defining the data before considering any forecasting method. In other words, we have to choose the parameters of the forecasting model, namely the appropriate historical data, the forecasting time step and the forecasting horizon. The challenge is to define the parameters of the forecasting model which agree with the functioning the multi-period optimization model.Furthermore, a feature of the marketplace is the temporality of its system. Thus, we propose an algorithm ensuring real-time aspect and so the fact that assignments are made every minute. The proposed algorithm works continuously all day long while optimizing every instant the offer/demand adequacy of Internet prospects and instantly considering the continuous flux of Internet prospects as well as the regular updating demand. Finally, in order to show the efficiency and the benefits that the marketplace can reap by the use of the proposed models, we conducted tests and various experiments on real data. These tests have allowed us to validate the proposed models and evaluate the quality of the results.The aim is twofold, giving a strong and formal framework to address the issue of the marketplace of Internet prospects but also proposing a generic framework to solve any problem similar to that of the marketplace of Internet prospects.

No description available.

This doctoral thesis represents pioneering research in integrating Smart Mobile Lockers with City Buses (SML-CBs) for e-commerce last-mile delivery, a novel concept rooted in the sharing economy. It explores the innovative use of underutilized urban bus capacities for parcel transportation while incorporating smart parcel lockers to facilitate self-pick-up by customers. Comprising six chapters, the thesis delineates its background, motivations, contributions, and organization in Chapter 1. Chapter 2 presents a comprehensive review of the recent literature on last-mile freight deliveries, including a bibliometric analysis, identifying gaps and opportunities for SML-CBs intervention. In Chapter 3, using survey data, we conduct empirical analytics to study Canadian consumers’ attitudes towards adopting SML-CBs, focusing on deterrents such as excessive walking distances to pick-up locations and incentives led by environmental concerns. This chapter also pinpoints demographic segments likely to be early adopters of this innovative delivery system. To address the concerns over walking distances identified in Chapter 3, Chapter 4 presents a prescriptive model and algorithms aimed at minimizing customer walking distance to self-pick-up points, considering the assignment of SML-CBs and customers. The case study results endorse the convenience of SML-CBs in terms of short walking distances. To systematically assess the sustainability benefits, a key motivator identified in Chapter 3, Chapter 5 includes analytical models for pricing and accessibility of SML-CBs. It also employs a hybrid life cycle assessment (LCA) methodology to analyze the sustainability performance of SML-CBs. It establishes system boundaries, develops pertinent LCA parameters, and illustrates substantial greenhouse gas (GHG) savings in both operational and life cycle phases when SML-CBs are utilized instead of traditional delivery trucks. The dissertation is concluded in Chapter 6, summarizing the principal contributions and suggesting avenues for future research. This comprehensive study not only provides empirical and analytical evidence supporting the feasibility and advantages of SML-CBs but also contributes to the literature on sustainable logistics and urban freight deliveries. / Thesis / Doctor of Philosophy (PhD) / This doctoral thesis represents pioneering research in integrating Smart Mobile Lockers with City Buses (SML-CBs) for e-commerce last-mile delivery. It explores the innovative use of underutilized urban bus capacities for parcel transportation while incorporating smart parcel lockers to facilitate self-pick-up by customers. Comprising six chapters, the thesis delineates its background, motivations, contributions, and organization in Chapter 1. Chapter 2 presents a comprehensive review of the recent literature on lastmile freight deliveries. In Chapter 3, we study Canadian consumers’ attitudes towards adopting SML-CBs, focusing on deterrents such as excessive walking distances to pickup locations and incentives led by environmental concerns. To address the concerns over walking distances identified in Chapter 3, Chapter 4 presents models and algorithms for operating SML-CBs. Chapter 5 presents an assessment of the sustainability of SML-CBs. The dissertation is concluded in Chapter 6, summarizing the principal contributions and suggesting avenues for future research.

An increase in demand for sawed wood products is the reason why Norra Timber has to expand their facility at Sävar Sawmill. During the expansion, a new log sorting will be implemented which can sort timber with different characteristics and qualities compared to the current log sorting. The placement of the new log sorting and the logistics after the construction has not been decided. Therefore, the purpose of this thesis is to suggest a design of the new timber yard which includes placement of the new log sorting, log piles and roads to minimize travel distance for tractors between the log sorting and the saw. The thesis project started with examining the opportunities and challenges that exist in timber logistics through a literature study. Afterwards, the current logistics at Sävar Sawmill were studied. Relevant data was collected to create different layout suggestions and to determine which optimization model that should be used. The placement of the log sorting was determined after the data collection, together with a steering group at Sävar Sawmill. Three layout suggestions were created after the placement of the new log sorting and were restricted to the current asphalted surface for timber handling. All layout suggestions should have a storage capacity with the volumes 15 000 m3f, 20 000 m3f and 35 000 m3f. The unit of volume m3f, describes the solid volume of timber without bark. The assignment problem with the Hungarian algorithm was used to optimize the placement of log classes on the timber yard. Thereafter transport distances and driving hours were calculated with three different production levels. The results show that all timber fits in the timber yard for the three layout suggestions when the storage levels are 15 000 m3f and 20 000 m3f, where an optimal solution is found. In the beginning it was not possible to find an optimal solution when the storage levels increased to 35 000 m3f. To find a solution, one constraint was relaxed that allowed the log piles to become overfilled. Norra Timber did not believe a solution at 35 000 m3f existed and therefore accepted the relaxation. Layout suggestion 1 had the least amount of overfilled log piles and layout suggestion 2 had the most. There was a significant difference for the travel distance per year between the layout suggestions when the storage level was low compared to high. Layout suggestion 1 had the longest travel distance per year and layout suggestion 3 had the shortest for all the production levels. The positions and the number of log piles will be the same regardless the production levels, but the travel distance will increase when the production level increases. The number of driving hours is calculated from the travel distances to point out the differences in working hours for the tractor drivers. Layout suggestion 3 will be proposed to use in the future based on the result from the optimization model. The layout suggestion 3 has significant shorter transport distance for the two lower storage levels compared to the other suggestions. The tractor drivers also appreciated that layout suggestion 3 had more available log piles and that the placement of the log piles will ease their daily work and save many working hours. / En ökad efterfrågan på sågade trävaror gör att Norra Timber är i behov av att expandera sin nuvarande anläggning på Sävar såg. Vid expansionen kommer en ny timmersortering installeras som kan sortera timret på flera egenskaper och kvaliteter jämfört med den befintliga. Varken placeringen av den nya timmersorteringen eller hur logistiken ska fungera efter expansionen är bestämt. Syftet med examensarbetet är att ta fram ett förslag på hur Norra Timber ska designa området med placering av den nya timmersorteringen, vältplatser och vägar för att minimera transportavstånd för traktorerna mellan timmersorteringen och sågen.  Examensarbetet inleddes med att undersöka vilka möjligheter och utmaningar som finns inom timmerlogistik genom en litteraturstudie. Logistiken på Sävar såg studerades sedan och varje aktivitet förklarades i en nulägesbeskrivning. Relevant fakta samlades in för att kunna skapa olika designförslag och avgöra vilken optimeringsmodell som skulle användas. Efter datainsamling bestämdes placeringen av den nya timmersorteringen tillsammans med en projektgrupp på Sävar såg. Utifrån den nya timmersorteringens placering skapades tre olika designförslag som var begränsade till den asfalterade ytan vid den nuvarande timmerhanteringen. Alla designförslag skulle klara av en lagernivå på 15 000 m3f, 20 000 m3f och 35 000 m3f. Volymenheten m3f står för den fasta volymen timmer utan bark. För att optimera var timmerklasserna skulle placeras i vältor på timmerplanen användes tillordningsproblemet med Hungarian algoritm där indatat anpassades efter lager- och produktionsnivå. Transportavstånd och körtimmar räknas sedan ut för alla designförslag med tre olika produktionsnivåer.   Resultatet visar att när lagernivåerna är 15 000 m3f och 20 000 m3f får allt timmer plats på timmerplanen i alla designförslag och modellen hittar en optimal lösning. När lagernivån ökade till 35 000 m3f kunde inte en optimal lösning hittas till en början. För att hitta en lösning relaxerades ett bivillkor vilket gjorde att överfulla vältor tilläts. Norra Timber trodde inte en lösning vid 35 000 m3f existerade och accepterade därför relaxationen. Minst antal överfulla vältor hade designförslag 1 och designförslag 2 hade högst antal. Designförslagens transportavstånd per år skiljer sig mycket mellan den lägsta lagernivån jämfört med den högsta. Designförslag 1 har längst avstånd och designförslag 3 har kortast avstånd för alla lagernivåer. Oavsett vilken produktionsnivå sågen har kommer vältplaceringarna att vara samma för ett designförslag där endast den totala körsträckan ökar. Antal körtimmar beräknas utifrån transportavstånd och presenteras för att visa på skillnaderna mellan traktorförarnas arbetstid. Utifrån optimeringsmodellens resultat rekommenderas Norra Timber att designa den nya timmerplanen på Sävar såg efter designförslag 3. Förslaget har signifikant kortare transportavstånd vid de två lägre lagernivåerna jämfört med de andra två designförslagen. Traktorförarna uppskattade också att förslaget hade fler vältplatser och vältornas placering som kommer underlätta deras vardagliga arbete och spara in många arbetstimmar.

Cette thèse développe des méthodes d'optimisation pour la gestion de la Supply Chain et a pour thème central la flexibilité définie comme la capacité à fournir un service ou un produit au consommateur dans un environnement incertain. La recherche a été menée dans le cadre d'un partenariat entre Argon Consulting, une société indépendante de conseil en Supply Chain et l'École des Ponts ParisTech. Dans cette thèse, nous développons trois sujets rencontrés par Argon Consulting et ses clients et qui correspondent à trois différents niveaux de décision (long terme, moyen terme et court terme).Lorsque les entreprises élargissent leur portefeuille de produits, elles doivent décider dans quelles usines produire chaque article. Il s'agit d'une décision à long terme, car une fois qu'elle est prise, elle ne peut être facilement modifiée. Plus qu'un problème d'affectation où un article est produit par une seule usine, ce problème consiste à décider si certains articles doivent être produits par plusieurs usines et par lesquelles. Cette interrogation est motivée par la grande incertitude de la demande. En effet, pour satisfaire la demande, l'affectation doit pouvoir équilibrer la charge de travail entre les usines. Nous appelons ce problème le multi-sourcing de la production. Comme il ne s'agit pas d'un problème récurrent, il est essentiel de tenir compte du risque au moment de décider le niveau de multi-sourcing. Nous proposons un modèle générique qui inclut les contraintes techniques du problème et une contrainte d'aversion au risque basée sur des mesures de risque issues de la théorie financière. Nous développons un algorithme et une heuristique basés sur les outils standards de la Recherche Opérationnelle et de l'Optimisation Stochastique pour résoudre le problème du multi-sourcing et nous testons leur efficacité sur des données réelles.Avant de planifier la production, certains indicateurs macroscopiques doivent être décidés à horizon moyen terme tels la quantité de matières premières à commander ou la taille des lots produits. Certaines entreprises utilisent des modèles de stock en temps continu, mais ces modèles reposent souvent sur un compromis entre les coûts de stock et les coûts de lancement. Ces derniers sont des coûts fixes payés au lancement de la production et sont difficiles à estimer en pratique. En revanche, à horizon moyen terme, la flexibilité des moyens de production est déjà fixée et les entreprises estiment facilement le nombre maximal de lancements. Poussés par cette observation, nous proposons des extensions de certains modèles classiques de stock en temps continu, sans coût de lancement et avec une limite sur le nombre d'installations. Nous avons utilisé les outils standard de l'Optimisation Continue pour calculer les indicateurs macroscopiques optimaux.Enfin, la planification de la production est une décision à court terme qui consiste à décider quels articles doivent être produits par la ligne de production pendant la période en cours. Ce problème appartient à la classe bien étudiée des problèmes de Lot-Sizing. Comme pour les décisions à moyen terme, ces problèmes reposent souvent sur un compromis entre les coûts de stock et les coûts de lancement. Fondant notre modèle sur ces considérations industrielles, nous gardons le même point de vue (aucun coût de lancement et une borne supérieure sur le nombre de lancement) et proposons un nouveau modèle.Bien qu'il s'agisse de décisions à court terme, les décisions de production doivent tenir compte de la demande future, qui demeure incertaine. Nous résolvons notre problème de planification de la production à l'aide d'outils standard de Recherche Opérationnelle et d'Optimisation Stochastique, nous testons l'efficacité sur des données réelles et nous la comparons aux heuristiques utilisées par les clients d'Argon Consulting / This thesis develops optimization methods for Supply Chain Management and is focused on the flexibility defined as the ability to deliver a service or a product to a costumer in an uncertain environment. The research was conducted throughout a partnership between Argon Consulting, which is an independent consulting firm in Supply Chain Operations and the École des Ponts ParisTech. In this thesis, we explore three topics that are encountered by Argon Consulting and its clients and that correspond to three different levels of decision (long-term, mid-term and short-term).When companies expand their product portfolio, they must decide in which plants to produce each item. This is a long-term decision since once it is decided, it cannot be easily changed. More than a assignment problem where one item is produced by a single plant, this problem consists in deciding if some items should be produced on several plants and by which plants. This is motivated by a highly uncertain demand. So, in order to satisfy the demand, the assignment must be able to balance the workload between plants. We call this problem the multi-sourcing of production. Since it is not a repeated problem, it is essential to take into account the risk when making the multi-sourcing decision. We propose a generic model that includes the technical constraints of the assignment and a risk-averse constraint based on risk measures from financial theory. We develop an algorithm and a heuristic based on standard tools from Operations Research and Stochastic Optimization to solve the multi-sourcing problem and we test their efficiency on real datasets.Before planning the production, some macroscopic indicators must be decided at mid-term level such as the quantity of raw materials to order or the size of produced lots. Continuous-time inventory models are used by some companies but these models often rely on a trade-off between holding costs and setups costs. These latters are fixed costs paid when production is launched and are hard to estimate in practice. On the other hand, at mid-term level, flexibility of the means of production is already fixed and companies easily estimate the maximal number of setups. Motivated by this observation, we propose extensions of some classical continuous-time inventory models with no setup costs and with a bound on the number of setups. We used standard tools from Continuous Optimization to compute the optimal macroscopic indicators.Finally, planning the production is a short-term decision consisting in deciding which items must be produced by the assembly line during the current period. This problem belongs to the well-studied class of Lot-Sizing Problems. As for mid-term decisions, these problems often rely on a trade-off between holding and setup costs. Basing our model on industrial considerations, we keep the same point of view (no setup cost and a bound on the number of setups) and propose a new model. Although these are short-term decisions, production decisions must take future demand into account, which remains uncertain. We solve our production planning problem using standard tools from Operations Research and Stochastic Optimization, test the efficiency on real datasets, and compare it to heuristics used by Argon Consulting's clients