This thesis develops a method to optimize the inventory-related performance of a VMI (Vendor Managed Inventory) in retailing environments, for two successive products with overlapping lifecycles, under stock-dependent demand. The study refers to existing research in different fields, such as inventory policies and VMIs, retailing of substitutable products, stock-dependent demands and product lifecycle management. However, no study encompassing all these research streams could be found, and thus an abductive approach is developed, aiming at building new theory. The thesis draws upon a case study at Sony Germany, which has started an ambitious VMI initiative with the largest retailer of consumer electronics products in Germany. First, stock and sales data available, along with insights collected among employees, is used to understand the key profit-drivers when lifecycles of the two products overlap, and a set of indicators is propounded to measure them. The pattern of sales in relation to inventories of the two products is studied, and results in the validation of the stock-dependent demand assumption, with demand following a Poisson distribution of parameter λ [on-hand stock]. Demand for the new product is also found to be negatively affected by stock levels of the old product, in an exponential way. Second, a model is built and a scenario- based simulation embedding the patterns previously established is performed to evaluate different strategies to steer the stock levels in the VMI. Scenarios are evaluated against the proposed set of indicators, but no scenario is found to over perform consistently the others. Nevertheless interesting patterns emerge and it is possible to relate the performance observed to specificities of scenarios and product contexts. Using the patterns identified, a set of guidelines is suggested, along with proposals for practical implementation.

O foco dessa dissertação está na gestão de estoques em sistemas multicamadas. O modelo de simulação construído considera o desempenho histórico de uma cadeia de distribuição de medicamentos versus a política de gestão proposta. Os objetivos principais do trabalho são: a avaliação quantitativa da política de cálculo de necessidades aplicada na gestão de sistemas multicamadas, a verificação da importância da cooperação entre os elos da cadeia de distribuição para gestão do fluxo de materiais e o estudo das curvas que representam o dilema ‘nível de serviço’ versus ‘custo total da cadeia’. O modelo considera o fluxo de materiais a partir do estoque em processo do laboratório até a venda para as farmácias, que pode ser aproximada pela demanda dos medicamentos visto que os estoques das farmácias são relativamente pequenos e constantes ao longo do tempo. A modelagem de custos leva em conta o custo de estoque do laboratório e dos distribuidores, o custo de pedido dos distribuidores, o custo de transporte, o custo de entrega com atraso do laboratório e o custo de venda perdida dos distribuidores. Especificamente, são considerados cenários com e sem o compartilhamento de informações entre as empresas da cadeia. Consideram-se também cenários com e sem sazonalidade na demanda. Inicialmente, cada cenário simulado é preparado com a definição do ‘período transitório da simulação’, ‘horizonte de simulação’ e ‘número de réplicas’ necessárias. Depois disso, é feito o delineamento de experimentos para identificar quais variáveis de decisão têm efeito significativo sobre o custo total da cadeia. Finalmente, é feita uma busca da parametrização de cada um dos cenários que apresente o melhor custo total da cadeia. Os resultados da simulação mostraram que as práticas atualmente empregadas na gestão dos estoques das empresas podem ter seu desempenho melhorado com a utilização da política simulada na pesquisa. Os cenários nos quais se considerou o compartilhamento de informações tiveram desempenhos semelhantes aos sem esse compartilhamento. Dessa forma, para a política simulada, conclui-se que o valor do compartilhamento de informações foi relativamente pequeno. Nas simulações pode-se verificar a melhoria simultânea do nível de serviço e do nível de estoques da cadeia. Isso mostra que a política simulada mudou o dilema (trade-off) que interliga antagonicamente essas duas características de desempenho do sistema. / This dissertation focuses on the inventory management for multi-echelon systems. The simulation model proposes a new inventory management policy and compares it to the historical performance of a medicine supply chain. The main objectives of this research are: the quantitative analysis of the method used for the calculation of material requirements in multi-echelon systems; the verification of the importance of the cooperation between the components of the supply chain to the material flow management; and the analysis of the curves which represent the trade-off between ‘service level’ and ‘total cost’. The model takes into account the material flow from the laboratory’s ‘work in process’ up to the sales to the drugstores, which can be approximated by the demand of the final consumer, since the inventory kept by drugstores is relatively small and constant in time. The costs are calculated considering: the laboratory’s and distributors’ inventory costs, the cost of orders from the distributors, the transportation cost, the laboratory’s cost of late delivery and the distributors’ cost of lost sales. Scenarios with and without the sharing of information between the components of the supply chain were both considered. The same is true for scenarios with and without seasonality in the demand. Initially, each scenario was prepared with the definition of the ‘warm-up’ period, the simulation horizon and the amount of required replications. Secondly, the design of experiments (DOE) was done in order to determine which decision variables have influence on the supply chain total cost. Finally, each scenario was tested with many different parameters in order to find the lowest cost for the supply chain. The simulation results have showed that the procedures currently applied for the inventory management can have their performance improved by the use of the policy proposed in this research. The results for the scenarios with the sharing of information were similar to the ones for the scenarios without the sharing. For that reason, we can conclude that, for the proposed inventory management policy, the value of the sharing of information through the supply chain was relatively small. In the simulations, both the ‘service level’ and the ‘total cost’ have improved. In this manner, it can be said that the new policy has improved this trade-off.

<p>Bakgrund: Historiskt har företag haft stora lager för att kunna möta kundernas efterfrågan. I takt med att kundanpassning och flexibilitet har ökat har det blivit allt dyrare och näst intill omöjligt att hålla lager som kan tillgodose kundernas behov. Att styra sitt lager så att det motsvarar efterfrågan har nästan varit en omöjlighet. En lösning på lagerstyrningsproblematiken är Vendor Managed Inventory (VMI) som innebär ett tätare samarbete mellan kund och leverantör. Kunden tillhandahåller information om lager och efterfrågan och leverantören tar över ansvaret för att varorna i kundens lager inte ska ta slut. Litteraturen kring VMI tar upp många positiva effekter som kommer att inträffa vid ett VMI-samarbete. Dock är det skralt med empiriska undersökningar beträffande effekterna av införandet av ett VMI-samarbete.</p><p> Syfte: Syftet med uppsatsen är att undersöka ett VMI-samarbete mellan en leverantör och en kund för att se om det finns empiriskt stöd för de kostnads- och leveransserviceeffekter som teorierna kring VMI tar upp. </p><p>Genomförande: Vi har undersökt samarbetet mellan Abba Seafood och ICA Handlarna. Vi intervjuade personer på båda företagen. Respondenterna hade antingen ett övergripande ansvar för VMI-samarbetet eller kom i kontakt med VMI i det dagliga arbetet. </p><p>Resultat: Efter att ha analyserat samarbetet mellan Abba och ICA så kan vi konstatera att många av de positiva effekter som kan förväntas av ett VMI- koncept har infriats och några inte. Vad vi inte kan fastställa i alla lägen, är om det är just VMI som är bakgrunden till förbättringarna, eller om det helt enkelt är den förbättrade informationsspridningen. En stor fråga har varit om det verkligen är nödvändigt för leverantören att ta över styrningen av kundens lager för att förbättringarna ska vara tydliga.</p>

Bakgrund: Historiskt har företag haft stora lager för att kunna möta kundernas efterfrågan. I takt med att kundanpassning och flexibilitet har ökat har det blivit allt dyrare och näst intill omöjligt att hålla lager som kan tillgodose kundernas behov. Att styra sitt lager så att det motsvarar efterfrågan har nästan varit en omöjlighet. En lösning på lagerstyrningsproblematiken är Vendor Managed Inventory (VMI) som innebär ett tätare samarbete mellan kund och leverantör. Kunden tillhandahåller information om lager och efterfrågan och leverantören tar över ansvaret för att varorna i kundens lager inte ska ta slut. Litteraturen kring VMI tar upp många positiva effekter som kommer att inträffa vid ett VMI-samarbete. Dock är det skralt med empiriska undersökningar beträffande effekterna av införandet av ett VMI-samarbete. Syfte: Syftet med uppsatsen är att undersöka ett VMI-samarbete mellan en leverantör och en kund för att se om det finns empiriskt stöd för de kostnads- och leveransserviceeffekter som teorierna kring VMI tar upp. Genomförande: Vi har undersökt samarbetet mellan Abba Seafood och ICA Handlarna. Vi intervjuade personer på båda företagen. Respondenterna hade antingen ett övergripande ansvar för VMI-samarbetet eller kom i kontakt med VMI i det dagliga arbetet. Resultat: Efter att ha analyserat samarbetet mellan Abba och ICA så kan vi konstatera att många av de positiva effekter som kan förväntas av ett VMI- koncept har infriats och några inte. Vad vi inte kan fastställa i alla lägen, är om det är just VMI som är bakgrunden till förbättringarna, eller om det helt enkelt är den förbättrade informationsspridningen. En stor fråga har varit om det verkligen är nödvändigt för leverantören att ta över styrningen av kundens lager för att förbättringarna ska vara tydliga.

Introduction: Nowadays beverage companies must focus on maintaining healthy finishedgoods inventory stocks in order to be able to decrease inventory costs, meet customerrequirements and to obtain competitive advantage. However many beverage SMEdon’t have an accurate planning and forecasting to manufacturing inventories. Thereforethey often face the problem of optimization in inventory management due to several differentreasons. As a result, company loses its competitiveness. Thus, there is a need tocoordinate Inventory activities of beverage SMEs to improve inventories’ planning. The purpose of this study is to analyze how inventory management is organized in a small Chinese beverage company. Frame of reference: This research is based on the theoretical framework relates with InventoryManagement (IM) and Retailer-managed inventory (RMI), vendor-managed inventory(VMI) and Collaborative Planning, Forecasting and Replenishment (CPFR).Empirical Data were collected through personal interviews and organization documents. Methodology: The research strategy for this paper is a single case study. This strategy allows investigating topic in its real life context. The inductive approach is used for this research based on qualitative data. The major source of data collection was semi-structured interviews and the company's documents. For analyzing data categorization approach was applied. Conclusion: The study found that inventory management theories presented in scientificliteratures are used in practice. To achieve better inventory management for beverageSMEs, the authors summarize four importance parameters based on literatures and findings.The authors also provide some suggestions based on the importance parameters inthe conclusion to optimize the case company’s inventory management.

Le développement des technologies de l’information et de la communication que connait notre siècle a grandement facilité les pratiques d’échanges d’informations au sein des chaînes logistiques. Ces pratiques ont pu ainsi évoluer vers de nouvelles formes de collaborations entre entreprises, telles que le Partage d’Informations (PI) et le Vendor Managed Inventory (VMI). Le VMI est un mécanisme de coordination dans lequel le fournisseur a la responsabilité de la gestion des stocks de son client. Ce mécanisme repose sur plusieurs principes parmi lesquels un partage d’informations très développé entre les parties qui s’y engagent. Le PI et le VMI sont adoptés par les entreprises pour permettre une augmentation des profits et une réduction des coûts. Toutefois, leurs résultats sont mitigés et nécessitent encore un approfondissement de leur compréhension. La contribution de cette thèse se situe dans l’analyse des impacts de ces mécanismes sur des chaînes logistiques où tous les maillons sont des entreprises de production dont les efficacités peuvent être différentes. Pour ce faire, plusieurs scénarios ont été étudiés sur des chaînes logistiques constituées de trois échelons, chaque échelon peut appartenir à quatre classes d’efficacité. Ces chaînes peuvent répondre à deux types de demande du marché final ; une demande stable ou une demande variable. De plus, plusieurs mécanismes de coordination sont étudiés : les mécanismes de gestion standard, de partage d’informations entre deux échelons, de partage d’informations entre trois échelons, de VMI entre deux échelons, puis de VMI étendu aux trois échelons. L’outil utilisé pour mener ces expérimentations est le logiciel de simulation à évènements discrets Arena. L’interprétation des résultats a montré que le mécanisme de coordination avec partage d’informations n’a pas eu d’amélioration très significative sur les résultats. En effet, puisque les entreprises ont des capacités de production finies, la disponibilité de l’information n’a pas permis d’obtenir des résultats différents. Le VMI, de son côté, a pu réaliser des réductions des stocks et des coûts de la chaîne logistique. Ces réductions ont été plus importantes chez les chaînes logistiques dont les maillons sont de faibles efficacités. Chez ces dernières, ce sont les deux parties concernées par le VMI (le fournisseur et le donneur d’ordres) qui ont tiré des avantages du VMI. Chez les chaînes logistiques constituées de maillons de haute efficacité, le VMI a permis une réduction des coûts moins importante, car ces chaînes logistiques sont déjà de performance élevée. Pour celles ci, c’est le client qui a tiré profit du VMI, alors que le fournisseur VMI a subi une augmentation des coûts suite à l’augmentation de la fréquence de transport qu’a impliqué ce mécanisme. / The advent of new information and communication technology has greatly facilitated the information exchange practices within supply chains. These practices recently evolved into new forms of collaborations between companies such as Information Sharing (IS) and Vendor Managed Inventory (VMI). The VMI is a coordination mechanism where the supplier is responsible for the inventory management of his customer. This mechanism is based on several principles, including developed information sharing between involved parties. The use of IS and VMI allow companies to increase profits and reduce costs. However, the results about the benefits from their use remain not clear. This motivates the need for new assessments and a better understanding of their effects. This thesis main contribution lies in the analysis and comprehension of IS and VMI’s impacts on supply chains. Especially, we address the issue of supply chains where tiers are production companies with different effectiveness levels. The examined scenario is based on a three tiers supply chain where each tier can belong to four effectiveness classes. The supply chain can respond to two types of end market demands: stable demands or fluctuant demands. In addition, several coordination mechanisms are studied: (i) standard management mechanism, (ii) information sharing between two enterprises, (iii) information sharing between three enterprises, (iv) VMI and (v) Extended VMI to all the three enterprises. The tool used to conduct these experiments is the discrete event simulation software “Arena”. The interpretation of the results showed that the IS coordination mechanism has not very significant improvement. Indeed, as companies have finite capacity, the availability of information did not yield better results. Whereas, the VMI could achieve reductions in both inventory and supply chain costs. In addition, VMI improved profits of the two parties, the vendor and the customer. Finally, the advantages of VMI appear to be stronger when the overall supply chain is less effective.

O foco dessa dissertação está na gestão de estoques em sistemas multicamadas. O modelo de simulação construído considera o desempenho histórico de uma cadeia de distribuição de medicamentos versus a política de gestão proposta. Os objetivos principais do trabalho são: a avaliação quantitativa da política de cálculo de necessidades aplicada na gestão de sistemas multicamadas, a verificação da importância da cooperação entre os elos da cadeia de distribuição para gestão do fluxo de materiais e o estudo das curvas que representam o dilema ‘nível de serviço’ versus ‘custo total da cadeia’. O modelo considera o fluxo de materiais a partir do estoque em processo do laboratório até a venda para as farmácias, que pode ser aproximada pela demanda dos medicamentos visto que os estoques das farmácias são relativamente pequenos e constantes ao longo do tempo. A modelagem de custos leva em conta o custo de estoque do laboratório e dos distribuidores, o custo de pedido dos distribuidores, o custo de transporte, o custo de entrega com atraso do laboratório e o custo de venda perdida dos distribuidores. Especificamente, são considerados cenários com e sem o compartilhamento de informações entre as empresas da cadeia. Consideram-se também cenários com e sem sazonalidade na demanda. Inicialmente, cada cenário simulado é preparado com a definição do ‘período transitório da simulação’, ‘horizonte de simulação’ e ‘número de réplicas’ necessárias. Depois disso, é feito o delineamento de experimentos para identificar quais variáveis de decisão têm efeito significativo sobre o custo total da cadeia. Finalmente, é feita uma busca da parametrização de cada um dos cenários que apresente o melhor custo total da cadeia. Os resultados da simulação mostraram que as práticas atualmente empregadas na gestão dos estoques das empresas podem ter seu desempenho melhorado com a utilização da política simulada na pesquisa. Os cenários nos quais se considerou o compartilhamento de informações tiveram desempenhos semelhantes aos sem esse compartilhamento. Dessa forma, para a política simulada, conclui-se que o valor do compartilhamento de informações foi relativamente pequeno. Nas simulações pode-se verificar a melhoria simultânea do nível de serviço e do nível de estoques da cadeia. Isso mostra que a política simulada mudou o dilema (trade-off) que interliga antagonicamente essas duas características de desempenho do sistema. / This dissertation focuses on the inventory management for multi-echelon systems. The simulation model proposes a new inventory management policy and compares it to the historical performance of a medicine supply chain. The main objectives of this research are: the quantitative analysis of the method used for the calculation of material requirements in multi-echelon systems; the verification of the importance of the cooperation between the components of the supply chain to the material flow management; and the analysis of the curves which represent the trade-off between ‘service level’ and ‘total cost’. The model takes into account the material flow from the laboratory’s ‘work in process’ up to the sales to the drugstores, which can be approximated by the demand of the final consumer, since the inventory kept by drugstores is relatively small and constant in time. The costs are calculated considering: the laboratory’s and distributors’ inventory costs, the cost of orders from the distributors, the transportation cost, the laboratory’s cost of late delivery and the distributors’ cost of lost sales. Scenarios with and without the sharing of information between the components of the supply chain were both considered. The same is true for scenarios with and without seasonality in the demand. Initially, each scenario was prepared with the definition of the ‘warm-up’ period, the simulation horizon and the amount of required replications. Secondly, the design of experiments (DOE) was done in order to determine which decision variables have influence on the supply chain total cost. Finally, each scenario was tested with many different parameters in order to find the lowest cost for the supply chain. The simulation results have showed that the procedures currently applied for the inventory management can have their performance improved by the use of the policy proposed in this research. The results for the scenarios with the sharing of information were similar to the ones for the scenarios without the sharing. For that reason, we can conclude that, for the proposed inventory management policy, the value of the sharing of information through the supply chain was relatively small. In the simulations, both the ‘service level’ and the ‘total cost’ have improved. In this manner, it can be said that the new policy has improved this trade-off.

During the last decade, research related to Supply Chain Management has got a great deal of attention. The focus has especially circulated around supply chain integration and centralisation due to the increasingly competitive global market. The aim of this thesis has been to investigate how the supply chain performance in international manufacturing companies could be improved. By having a qualitative approach, this thesis contributes to earlier conducted research by providing a holistic view on supply chain management. This is by the authors considered crucial to manage the complexity of supply chain management and supply chain change. The specific context examined in this thesis concerns the spare parts distribution of large international manufacturing companies. The methods used during the case study consisted of a thorough literature review, external interviews and workshops with experts within supply chain management and supply chain change, and several interviews with employees at different levels and functions at the focal company, Toyota Material Handling Europe. Two of the interviewed external experts were managers at the supply chain function at Volvo Construction Equipment and Ericsson. To answer the main research question, three sub-queries have been examined. The first one concerns what main areas of difficulty that can be identified in the current supply chain of the focal company and in international manufacturing companies in general. The second sub-query concerns which supply chain policies that could be used to solve identified areas of difficulty. Finally, the third sub-query concerns which prerequisites that could be identified to successfully manage change within supply chains. The results imply that Information and Inventory Management are the main supply chain related areas in need of improvements at the focal company, as well as in international manufacturing companies in general. Thereby supply chain performance could be improved if performance within these areas is enhanced. To solve these two identified areas of difficulty, four theoretical supply chain policies related to supply chain integration have been examined due to complexity, need of investments during an implementation, as well as each policy’s possibility to solve the identified areas of difficulty. The supply chain policy Vendor-Managed Inventory was considered the most appropriate policy for the focal company to implement. As a consequence, an evaluation of the focal company’s readiness to implement a Vendor-Managed Inventory policy was also conducted by using a supply chain readiness framework developed by Niranjan, Wagner and Nguyen (2012). Based on the literature review, including the theoretical evaluation of the appropriateness of implementing Vendor-Managed Inventory, together with the findings from the external expert interviews, the focal company is recommended to implement a Vendor-Managed Inventory strategy. However, the focal company is also recommended to see such an implementation as an opportunity to later investigate the possibility to also include large suppliers in the collaboration. This would increase the level of integration among supply chain members further and thereby secure the company has the possibility to receive the advantages associated with sharing information (including Points-of-Sales data) with all supply chain members.   From a theoretical perspective the conclusion is that Vendor-Managed Inventory, with its focus on supply chain integration through collaboration and information sharing among supply chain members, is considered appropriate to implement when companies want to improve performance in one or all of these areas. Furthermore, the usage of a consignment stock agreement might be an appropriate complement to Vendor-Managed Inventory due to the international context. However, the authors suggest that international manufacturing companies should strive towards including large suppliers in the supply chain collaboration to increase performance further. Thereby they should move towards capabilities promoted in the supply chain policy Collaborative Planning, Forecasting and Replenishment, which advocate a higher level of integration than Vendor-Managed Inventory. Another main finding pinpoints the importance of a well-formulated and communicated vision in the beginning of a transformation, to manage supply chain change successfully. As a consequence, the authors of this thesis expanded the supply chain framework developed by Chopra and Meindl (2010) to also include vision. In addition, legal has been added as an important supply chain driver since it affects supply chain possibilities and decisions. The added parts are considered critical for the framework to be applicable in an international and rapidly changing business environment. Furthermore, the authors suggest the extended framework should be used to support companies evaluate the current and a desired future supply chain in accordance with examined change management literature. / Supply Chain Management har under det senaste decenniet fått mycket uppmärksamhet. På grund av en ökande internationell handel har forskningen framförallt behandlat Integration och Centralisering inom distributionskedjor. Syftet med denna studie har varit att undersöka hur man kan förbättra prestandan av distributionskedjan hos internationella tillverkningsföretag. Genom ett kvalitativt angreppssätt bidrar denna studie med ett holistiskt synsätt av Supply Chain Management, vilket av författarna är ansett kritiskt för att kunna hantera komplexiteten relaterad till Supply Chain Management och förändringsarbete inom detta område. Studiens forskningsfråga har kunnat besvaras genom att undersöka tre delfrågor. Den första behandlar att identifiera huvudproblemområden i distributionskedjan hos fokusföretaget samt internationella tillverkningsföretag generellt. Den andra delfrågan behandlar vilka teoretiska supply chain policies som skulle kunna användas för att lösa de identifierade problemområdena, medan den tredje och sista delfrågan handlar om att identifiera förutsättningar för att kunna hantera förändringsarbete av, och inom, distributionskedjor på ett lyckat sätt. Samtliga delfrågor och huvudfrågan har kunnat besvaras genom genomförandet av en litteraturstudie, intervjuer och workshops med externa områdesexperter inom Supply Chain Management och Supply Chain Change, samt interna intervjuer med anställda på olika avdelningar och nivåer inom fokusföretaget, Toyota Material Handling Europe. Två av de intervjuade experterna utgjordes av chefer på logistikavdelningen på två stora internationella tillverkningsföretag. Företagen i fråga utgjordes av Volvo Construction Equipment respektive Ericsson. Resultaten visar att Informations- och Lagerhantering anses vara de huvudområden inom Supply Chain Management, vilka är i störst behov av förbättringar och förändringar på fokusföretaget samt i stora internationella tillverkningsföretag generellt. Därmed kan prestandan av distributionskedjan förbättras om företag fokuserar på dessa två områden. För att förbättra Informations- och Lagerhanteringen har fyra teoretiska supply chain policies utvärderats, vilka alla mer eller mindre fokuserar på att öka integrationen mellan medlemmar inom distributionskedjan. Genom att utvärdera dessa supply chain policies med avseende på komplexitet, implementationskostnader samt möjlighet att lösa de identifierade huvudproblemområdena, har författarna kunnat dra slutsatsen att policyn Vendor-Managed Inventory bör vara mest passande att implementera på fokusföretaget. I och med detta resultat utvärderades fokusföretagets lämplighet att implementera Vendor-Managed Inventory utifrån en teoretisk modell utvecklad av Niranjan, Wagner och Nguyen (2012). Resultatet av denna utvärdering stödde det tidigare antagandet att Vendor-Managed Inventory är lämpligt för fokusföretaget att implementera. Författarna rekommenderar dock att en VMI-implementation ska ses som ett första steg varefter förtaget även skall utvärdera möjligheten att inkludera sina större leverantörer och därmed öka integrationen av distributionskedjan ytterligare. Detta för att verkligen uppnå de fördelar informationsdelning kan medföra om information delas med samtliga medlemmar i kedjan. Författarna har med hjälp av dessa resultat kunnat dra den teoretiska och generella slutsatsen att Vendor-Managed Inventory, med dess fokus på att öka integrationen i distributionskedjan genom ökat samarbete och ökad informationsdelning mellan distributionskedjans medlemmar, anses lämplig att implementera då företag vill eller behöver förbättras inom dessa områden. Vidare kan avtalsmodellen Consignment Stock komplettera Vendor-Managed Inventory i en internationell kontext genom användandet av en legal ägare av lager, oavsett lagerposition. Författarna rekommenderar även att stora internationella tillverkningsföretag bör sträva mot att inkludera sina större leverantörer och därmed öka integrationen av, och samarbetet inom, distributionskedjan. Detta skulle medföra att prestandan av distributionskedjan förbättras ytterligare. Därmed bör de utvecklas mot supply chain policyn Collaborative Planning, Forecasting and Replenishment, vilken förespråkar en högre nivå av samarbete än Vendor-Managed Inventory. Vidare visar studien vikten av en välformulerad och kommunicerad Vision i början av större förändringsprojekt. Detta för att öka chanserna till lyckade och välmotiverade förändringar. I och med identifieringen av visionens vitala del i förändringsprojekt, vidareutvecklade författarna modellen; Supply Chain Decison-Making Framework, utvecklad av Chopra &amp; Meindl (2010), till att även inkludera Vision. Dessutom adderades Legala aspekter, då de påverkar både beslutsfattande och möjligheter inom en internationell kontext. Både Vision och Legala aspekter anses av författarna vara kritiska delar för att modellen skall vara applicerbar i en internationell och föränderlig miljö. I linje med forskning inom förändringshantering som identifierats i litteraturen, anses Chopra &amp; Meindl’s vidareutvecklade modell nu vara lämplig att användas som en hjälp för företag att utvärdera sin nuvarande och önskade framtida distributionsstruktur.

[pt] Tema: Este estudo investiga o Problema de Roteamento de Inventário (IRP) no contexto do Gerenciamento de Inventário pelo Fornecedor (VMI), uma prática comum na cadeia de suprimentos onde os fornecedores assumem a responsabilidade pela reposição. O IRP, um problema combinatório estudado amplamente há quase 40 anos, engloba três subproblemas distintos: programação de entregas, gerenciamento de estoque e roteamento de veículos. Problema: Apesar de sua idade, o IRP continua a atrair a atenção da indústria e da academia. O recente décimo segundo Desafio de Implementação DIMACS dedicou uma categoria ao IRP, e entre os benchmarks comumente utilizados, 401 instâncias ainda não possuem soluções ótimas, especialmente no desafiador subconjunto de instâncias grandes. Hipótese e Justificativa: O framework HGS proposto por Vidal et al. (2012) surgiu como uma ferramenta proeminente utilizada por várias equipes de forma satisfatória na competição. No entanto, até onde sabemos, o framework HGS não foi testada para o IRP. Este estudo propõe uma solução que combina o framework HGS com uma estratégia de busca local eficiente, o método NSIRP proposto por Diniz et al. (2020), para abordar o IRP. Metodologia: Implementamos a solução proposta e comparamos seu desempenho com 21 abordagens existentes, utilizando os benchmarks da literatura. Resumo dos Resultados: Nossa abordagem identificou 79 novas Melhores Soluções Conhecidas (BKS) dentre 1100 instâncias. Se aplicada sob as mesmas regras da competição DIMACS, nossa solução teria garantido o primeiro lugar. Contribuições e Impactos: Este trabalho contribui para o desenvolvimento contínuo de soluções para o IRP, oferecendo uma abordagem eficiente e competitiva que pode inspirar futuras pesquisas e aplicações práticas no campo do gerenciamento de estoque e roteamento de veículos. / [en] Theme: This study investigates the Inventory Routing Problem (IRP) within the context of Vendor-Managed Inventory (VMI), a prevalent supply chain practice where suppliers assume responsibility for replenishment. The IRP, a combinatorial problem that has been widely studied for almost 40 years, encompasses three distinct subproblems: delivery scheduling, inventory management, and vehicle routing. Problem: Despite its age, the IRP continues to attract industry and academia attention. The recent 12th DIMACS Implementation Challenge dedicated a track to the IRP, and among the commonly used benchmarks, 401 instances still lack optimal solutions, particularly in the challenging Large instance subset. Hypothesis and Justification: The HGS framework proposed by Vidal et al. (2012) emerged as a prominent tool used successfully by numerous teams in the competition. However, to the best of our knowledge, the HGS framework has not been tested for the IRP. This study proposes a method combining the HGS framework with an efficient local search strategy, namely NSIRP proposed by Diniz et al. (2020), to tackle the IRP. Methodology: We implemented the proposed method and compared its performance to 21 existing methods using the literature benchmarks. Summary of Results: Our approach identified 79 new Best Known Solutions (BKS) out of 1100 instances. If applied under the same rules as the DIMACS competition, our method would have secured the first place. Contributions and Impacts: This work contribute to the ongoing development of IRP methods, offering an efficient and competitive approach that may inspire further research and practical applications in the realm of inventory management and vehicle routing.

We live in an era where markets are more dynamic and the product life cycle is shorter, an era where concepts such as smart manufacturing and mass customization form part of daily life in industries and where consumption rates of products and services are rising. All these result in more dynamic, global, complex and fragile supply chains. Disruptions are negative impacts on business continuity in companies and when a supply chain is disrupted there is only one way to tackle the challenges originated and is the ability to be resilient. Based on a systematic literature review, this thesis lay out a framework to position Vendor Managed Inventory digital solutions in order to provide full visibility in the supply chains, and enhance agility and flexibility skill sets in the organizations to be resilient after massive disruptions such as the COVID-19. The conclusions of this work provide a positive outlook of the capabilities of VMI solutions to create more resilient supply chains. / Vi lever i en era där marknader är mer dynamiska och produkters livscykel kortare. En era där koncept som smart tillverkning och mass-anpassning är en del av dagliga livet i industrier och där konsumtionsnivåer av produkter och tjänster ökar. Allt detta resulterar i mer dynamiska, globala, komplexa och känsliga försörjningskedjor. Störningar påverkar kontinuiteten i verksamheten negativt hos företag och när en försörjningskedja påverkas av störningar finns det bara ett sätt att hantera utmaningarna som uppstår och det är genom förmågan att vara motståndskraftig. Baserad på systematisk litteratursökning, lägger denna avhandling fram ramverk för att positionera Vendor Managed Inventory digitala lösningar för att förse full synlighet i distributionskedjan och förbättra rörlighetens och flexibilitetens förmågor i organisationerna för att bli mera uthållig efter massiva störningar som COVID-19. Slutsatserna av detta arbete ger en positiv syn på möjligheterna för VMI-lösningar för att skapa mer motståndskraftiga försörjningskedjor.