With growing markets and customers being geographically spread out, more pressure is put on a company’s logistics processes and their inventory structures are becoming more complex. This puts more pressure on the inventory control solution provided by a company like IFS, that supports their customers with inventory control through the Inventory Planning and Replenishment module in IFS Applications. As their customers’ supply chains grow larger, their inventory structures become more complex the next step is to find a solution for the IPR module more suitable in a called multi-echelon structure, i.e. several tiers of stock locations, such as local, regional and central warehouses.   The purpose of this study is to compare a reorder point model with a solution suitable in a multi-echelon setting and investigate how they are able to manage uncertainties with service level targets.   A literature study was performed, to find previous research on inventory control in multi-echelon inventory systems. In the literature study, the importance of coordination and information sharing between the echelons was emphasized and used as a focus when finding a suitable multi-echelon model. To answer the purpose a theoretical model was formulated from the findings in previous research, with a replenishment method suitable in a multi-echelon environment. The inventory control models also included lot sizing method and a safety mechanism, where the difference between the models were their respective replenishment policy. The theoretical model was based on the replenishment method Distribution Requirements Planning (DRP), as it enables information sharing, coordination and synchronization of the supply chain, while the other inventory control model uses the Reorder Point method (ROP).   As information sharing was emphasized in previous research on multi-echelon systems, and the main difference between the two inventory control models is the information sharing in the DRP model, the important question to be answered with the comparison is; what effects and benefits can be achieved through information sharing in a multi-echelon inventory system? The two inventory control models were then simulated in Excel and exposed to even demand and seasonal variations in an inventory structure with three echelons and four sites, see figure below. When analyzing the results three evaluation criteria were used; difference in service levels, average inventory levels and if there were signs of overstocking in the regional and central warehouse, i.e. if the system was exposed to the bullwhip effect.   The analysis was carried out based on the criteria above and divided into three sections. First, differences between the models for even demand were investigated. The same procedure followed for seasonal demand, identifying differences and what caused them. Findings were then summed up at the end of the chapter. For even demand, differences were small and sharing information does not give large benefits. Under seasonal demand though, sharing information proved to be very beneficial, reducing average inventory held in the system by 60%, compared to not sharing information. This because sharing information together with synchronizing eliminates the bullwhip effect.   By testing different standard deviations, changing lead times and order quantities, using forecast or being blind to forecast, the robustness of the conclusions drawn from the analysis was put to the test. Carrying out a sensitivity analysis on the models served two purposes. First, finding more evidence promoting the benefits of synchronizing the supply chain and how important it is that the shared information is correct, otherwise the benefits are reduced. The second purpose was to validate that the models performed as expected when changing input data.   The conclusions were the following:   Information sharing enables synchronization of the supply chain Synchronization allows for reaching higher service levels with lower inventory levels   Findings suggest that by sharing information, which must be the first step, synchronizing the inventory system is possible. It is the synchronization that creates the real benefits, such as higher service levels and lower inventory levels. However, the quality and accuracy of the shared information was found to play an important role. Sharing inaccurate or wrong information increase the risk of the system starting to suffer from the bullwhip effect, resulting in higher inventory levels and lower service levels.

Supply chain leaders in the information technology industry face challenges regarding their ability to mitigate amplified demand and supply variability in a supply chain network--the bullwhip effect--and reduce adverse implications on their component supply chain networks. The purpose of this multiple case study was to explore the strategies supply chain leaders in the United States used to reduce the bullwhip effect. Bullwhip effect theory served as the conceptual framework. Participants in the study were 5 purposefully selected supply chain leaders in the state of Texas who successfully implemented strategies to reduce the bullwhip effect on their networks. Data were collected from semistructured interviews and analysis of documents from the participants' websites. The data were analyzed using the 5 data analysis steps consistent with Yin's approach: collection, stratification, reassembly, interpretation, and conclusion. Four themes emerged from data analysis: (a) collaboration strategy, (b) communication strategy, (c) component shortage reduction strategy, and (d) resource management strategy. Supply chain leaders might use the findings of this study to reduce the bullwhip effect within their networks and improve their profitability. The implications for positive social change include the potential for leaders to improve environmental sustainability by using effective supply chain strategies to reduce the accumulation of excess inventories, reduce transportation fuel usage, and lessen the consumption of natural resources.

Konsumentbeteende påverkas av olika faktorer, oro för kriser är något som kan förändra konsumentbeteendet och ha en stor påverkan på livsmedelskedjan. Under covid-19 syntes dess förändringar tydligt då rädsla och oro fick människor att bunkra. Liknande beteenden märktes även under början av kriget mellan Ryssland och Ukraina. Det har märkts av i form av tomma butikshyllor och att vissa butiker haft problem med beställningar. I nuläget har inte kriget stor påverkan på Sveriges försörjningskedja men det är svårt att bedöma hur det kommer se ut längre fram. På grund av den ökade efterfrågan leder det till variationer i beställningar som ökar längre bak i kedjan, detta fenomen kallas för bullwhip-effekten och startar hos konsumenter. Syftet med denna studie är att undersöka effekter i försörjningskedjan på grund av ändrat konsumentbeteende i en kris. För att uppfylla syftet och svara på frågeställningarna valdes ett kvantitativt förhållningssätt. Vi valde att göra en enkätundersökning för att få en stor representation av befolkningen. Enkäten syftar till att ge en uppfattning om konsumenters val och hur kriget och covid-19 påverkat deras konsumentbeteende och se exempelvis om de köper mer av vissa livsmedel eller bygger lager för att få en uppfattning om hur det påverkar försörjningskedjan.Slutsatsen blev att konsumentbeteendet från covid-19 inte har en stor påverkan på försörjningskedjan idag. Pandemin visade hur viktigt det är att livsmedelskedjan är flexibel och bör resultera i mer kontroll av lagerhållning och delning av information för att mildra bullwhip-effekten. En del respondenter uttryckte känslor av stress när de såg tomma hyllor i livsmedelsbutikerna sedan kriget i Ukraina började. Respondenterna visade också sig mer påverkade från sociala medier än vänner och familj. Trots antagande att de ej känt sig påverkade av kriget har ca 40% köpt extra av framför alltkonserver. Studien påvisade att många respondenter är oroliga för att framtida kriser kommer påverka försörjningskedjan. Om en ny kris skulle uppstå kommer vi förmodligen se liknande konsumentbeteende som i de två föregående kriserna. Detta resulterar i fortsatta störningar i kedjan och bullwhip-effekten. / Consumer behavior is affected by various factors, concern about crises is something that can change consumer behavior and have a major impact on the food chain. During covid19, the changes were seen clearly when fear and anxiety made people start hoarding food. Similar behaviors were also noticed during the beginning of the war between Russia and Ukraine. It has been noticed in the form of empty store shelves and that some stores have had problems with orders. At present, the war does not have a major impact on Sweden's supply chain, but it is difficult to assess what it will look like in the future. Due to the increased demand, it leads to variations in orders that increase further back in the chain, this phenomenon is called the bullwhip-effect and it starts with the consumers. The purpose of this study is to investigate effects in the supply chain due to changes in consumer behavior in a crisis. In order to fulfill the purpose and answer the questions, a quantitative approach was chosen. We chose to do a survey to get a large representation of the population. The survey aims to provide an idea of consumers choices and how the war and covid-19 affected their consumer behavior and see whether they buy more of certain foods or perhaps stockpile, to get an idea of how it affects the supply chain.The conclusion was that consumer behavior from covid-19 does not have a major impact on the supply chain today. The pandemic showed how important it is for the food chain to be flexible and should result in more control over inventory and information sharing to mitigate the bullwhip effect. Some respondents expressed feelings of stress when they saw empty shelves in grocery stores since the war in Ukraine began. The respondents also proved to be more influenced by social media than friends and family. Despite assuming they did not feel affected by the war, about 40% bought extra food, especially canned goods. The study showed that many respondents are worried that future crises will affect the supply chain. Should a new crisis arise, we will probably see similar consumer behavior as in the two previous crises. This results in continued chain disruptions and the bullwhip effect.

Yes / The lack of separation between urgent and non-urgent medical goods encourages sub-optimal vehicle fleet operations owing to the time critical nature of urgent items. An unattended electronic locker bank, to which individual urgent items can be delivered thereby separating urgent and non-urgent supply, was proposed for the Great Ormond Street Hospital in London, UK. This concept was quantified using ‘basic’ and ‘intuitive’ hill climbing optimisation models; and qualitatively using staff interviews and expert reviews. Results indicated that a locker bank with a fixed height (1.7 m) and depth (0.8 m) required a length of 4 m (basic model) and 3.63 m (intuitive model), to accommodate 100% of urgent consignments for a typical week. Staff interviews indicated the wider benefits such as staff personal deliveries.

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.

Background: An organization's ability to control bound material can be the difference between success or failure. Organizations that effectively work with supply chain management has strengthened their positions and increase their competitive edge on the global market. Organizations is the pharmaceutical industry has a major social responsibility by ensuring a continuous flow of medicines as well as pharmaceutical equipment. The industry is controlled by the strict regulations. The stringent security requirements for delivery reliability and delivery precision combined with extensive production regulations have resulted in these organizations having difficulty in maintaining even inventory levels.   Purpose: The study aims to investigating the correlation between high level of safety requirements in the pharmaceutical industry and high inventory levels with the help of a case study. The study wants to investigate consequences of such connection as well investigate potential solution in which organizations can reduce their inventory levels without jeopardizing the delivery precision and delivery safety of pharmaceutical organizations.   A case study has been conducted at the pharmaceutical company Fresenius Kabi who is a global market leader in the production of intravenous nutritional solutions.   Finding: Findings of the study indicates that safety requirements controlling the pharmaceutical industry have a major impact on the organization's production planning and storage. The consequences of the high security requirements results in in uneven production patterns and tied capital in high inventory levels. The consequences also indicated on a Bullwhip-effect. Lean management enables organizations in the pharmaceutical industry to establish even production patterns and reduce their inventory levels.   The study presents a new factor that prevents organizations in the pharmaceutical industry to reduce the number of articles. The new factor has a strong link to why organizations in the pharmaceutical industry have high inventory levels. / Bakgrund: Hantering av lager och uppbundet material kan vara avgörande för en organisations framgång eller misslyckande. En ökad globalisering av dagens marknad har lett till att organisationer som effektivt arbetar med supply chain management stärker sina positioner och ökar sina konkurrensfördelar. En bransch på den globala marknaden som verkar under håra regleringar är läkemedelsbranschen. Branchen har ett stort samhällsansvar genom att säkerställa ett kontinuerligt flöde av läkemedel samt läkemedelsutrustning. De hårda säkerhetskraven på leveranssäkerhet och leveransprecision i kombination med omfattande produktionsregleringar har resulterat i att dessa organisationer har svårt att upprätthålla jämna lagernivåer. Syfte: Med hjälp av en fallstudie vill studien undersöka hur sambandet mellan höga säkerhetskrav och höga lagernivåer inom läkemedelsbranschen ser ut. Studien vill undersöka hur sambandet påverkar organisationer inom läkemedelsbranschen samt analysera hur man medhjälp av olika åtgärder kan minska lagernivåer utan att äventyra organisationernas leveransprecision och leveranssäkerhet. Fallstudien är baserad på läkemedelsorganisationen Fresenius Kabi. Fresenius Kabi är en global aktör som är marknadsledande inom produktion av intravenösa näringslösningar. Studien har undersökt produkten smofkabvien som produceras i Uppsala i syfte till att besvara studiens frågeställning. Med hjälp av intervjuer och insamlad sekundärdata besvaras studiens syfte. Slutsats: Studienkonstaterar att säkerhetskraven som reglerar läkemedelsbranschen har en stor inverkan på organisationens produktionsplanering och lagerhållning. Resultatet av de höga säkerhetskraven resulterar i ojämna beställning-och produktionsmönster vilket resulterar i hög kapitalbindning samt indikerar på en potentiell Bullwhip-effekt inom försörjningskedjan. Med hjälp av Lean management, heijunka och just-in-time kan organisationer inom läkemedelsbranschen upprätta jämna produktion-och beställningsmönster samt reducera sina lagernivåer. Studien presenterar en ny faktor vilken förhindrar organisationer inom läkemedelsbranschen möjlighet att reducera antalet artiklar. Den nya faktorn har en stark koppling till varför organisationer inom läkemedelsbranschen höga lagernivåer.

Made available in DSpace on 2016-03-15T19:25:47Z (GMT). No. of bitstreams: 1 Eduardo Roque Mangini.pdf: 1190434 bytes, checksum: cf196a3b431423c3d80304b0db4442bb (MD5) Previous issue date: 2007-02-07 / Supply chain involves all the activities associated to the handling of products since the very stage of raw materials up to the delivery of the manufactured goods to the final consumer which includes information sources and the attainment of these, the production schedule, processing order, inventory management, transportation, storage and costumer service. The relation of existing dependence among the participants of supply chain activities and resources causes consequences of negative nature when variation in any section or stage of the process occurs, phenomenon known as bullwhip effect. This phenomenon, also known as effect Forrester, is related with the increase of variation that occurs due to the up making of decisions related to political and organizational choices of investment front to the customers demand. The way the companies react to this whip effect, that is, the performance achieved is evaluated by the customers within aspects such as product quality, schedule reliability, order flexibility, delivery punctuality and last but not least a competitive final cost. These aspects are known as performance measures or competitive priorities. The main objective of this research is verifying the influence of the whip effect management within the food industry companies and the specific aim is mapping the generating features of the whip effect in this sector, besides, acknowledging the existence of such effect in levels of the supply chain and highlight the measures of control of the whip effect which are being used by the plants and also verifying the direct relationship of the bullwhip effect with the performance of everyone involved in the supply chain system. Research of qualitative and quantitative order has been lead in association with supermarkets of São Roque and Ibiúna area, quantitative surveys with the supermarkets as well as wholesale companies and Food processing companies. The results of the research point to the existence of the bullwhip effect, perceived and caused by the consumers, and amplified for the existence of promotion in the supermarkets companies, lack of sharing information among the companies of the supply chain as well as the absence of tools of electronic integration. The bullwhip effect observed also influences the performance of the organizations, mainly in flexibility and trustworthiness, affecting the Food processing companies corporative image. / A cadeia de suprimentos envolve todas as atividades associadas com a movimentação de produtos desde o estágio de matéria prima até a entrega do produto ao consumidor final, incluindo fontes de informações e obtenção destas, cronograma de produção, ordem de processamento, gerenciamento de inventário, transporte, armazenamento e serviço de atendimento ao cliente. A relação de dependência existente entre os participantes da cadeia de suprimentos, atividades e recursos causam conseqüências de natureza negativa quando ocorre variabilidade em qualquer sentido na cadeia de suprimentos, fenômeno este conhecido como efeito chicote. Este fenômeno, também conhecido como efeito Forrester, está relacionado com a amplificação e variabilidade que ocorrem pela antecipação de decisões, políticas, formas organizacionais e escolha de investimento frente a demanda dos consumidores. O modo como as empresas reagem ao efeito chicote, ou seja, o desempenho apresentado, é avaliado pelos clientes nos aspectos relacionados com qualidade de produtos, confiabilidade no prazo estipulado, flexibilidade com relação à quantidade, agilidade ou velocidade na entrega e um preço competitivo, o que sugere um baixo custo geral. Esses aspectos, são conhecidos como medidas de desempenho ou prioridades competitivas. O objetivo principal deste trabalho foi verificar a influência do gerenciamento do efeito chicote nas empresas relacionadas com a indústria alimentícia, e os objetivos específicos foram mapear os fatores que promovem o efeito chicote na indústria alimentícia, verificar a presença do efeito chicote nos vários níveis da cadeia de suprimentos e destacar fatores de controle do efeito chicote que estão sendo utilizados pelas empresas, além de verificar o relacionamento do efeito chicote com o desempenho dos participantes dessa cadeia de suprimentos. Foram conduzidas pesquisas de natureza qualitativa e quantitativa com empresas supermercadistas da região de São Roque e Ibiúna e pesquisas quantitativas com os clientes das empresas supermercadistas bem como com empresas atacadistas e fabricantes de produtos alimentícios. Os resultados das pesquisas apontam para a existência do efeito chicote, percebido e ocasionado pelos consumidores, e amplificado pela existência de promoção nas empresas supermercadistas, falta de compartilhamento de informações entre as empresas da cadeia de suprimentos bem como pela ausência de ferramentas de integração eletrônica. O efeito chicote observado, influencia também o desempenho das organizações, principalmente na flexibilidade e confiabilidade, afetando a imagem corporativa das empresas da indústria alimentícia.

Enligt Carlsson och Rönnqvist (2005) och Frayret et al. (2007) blir det allt viktigare att arbeta med supply chain management inom trävaruindustrin. En utmaning är att finna ett arbetssätt för att hantera variationen i kundens efterfrågan. Idag hanteras variationen oftast genom onödigt stor lagerhållning (Lee et al., 1997b; So och Zheng, 2003).                                                                                 Syftet med studien är att utreda påverkande faktorer som bidrar till en varierande efterfrågan inom trävaruindustrin samt föreslå hur uppkomsten av dessa kan undvikas. För att svara på syftet har tre frågeställningar tagits fram och en fallstudie genomfördes på ett hyvleri. Informationsinsamlingen har skett genom intervjuer av anställda från olika avdelningar samt litteraturstudier. Studien visar att det finns flera utmaningar när det är stor variation på efterfrågan såsom brist på tillgång till prognoser och kommunikationsbrist med kunder. Det medför att planeringen av råvaruåtgången försvåras och det leder till svårigheter att uppnå leveransprecision.   Slutsatsen visar att de påverkande faktorer som bidrar till en varierad efterfrågan är prisvariationer, orderstorlek och orderfrekvens. Prisvariationer kan undvikas genom ABC-indelning av produkterna utifrån produktefterfrågan. Prognoser underlättar uppskattning av efterfrågan men för ett fungerande prognosarbete krävs samsyn, nära relation samt god kommunikation mellan kund och leverantör. Problem med orderstorlek och orderfrekvens kan reduceras om kunden får avgöra orderstorleken utan att specifika krav måste uppfyllas. Slutsatsen visar även att faktorer såsom väderlek, trender, mode, helgdagar och rotavdragets eventuella försvinnande påverkar variationen i efterfrågan. / According to Carlsson & Rönnqvist (2005) and Frayret et al. (2007) supply chain management in the wood products industry is getting more important. One of the challenges is to find a way to deal with customer’s fluctuating demand. Traditional solution to handle fluctuating demand is large inventory (Lee et al., 1997b; So & Zheng, 2003), which causes often high inventory cost for effective supply chain management.   The aim of the study is to investigate factors that affect a fluctuating demand in the wood products industry and suggest how to reduce the fluctuating demand through related factors analysis in order to improve Demand-Supply chain management efficiency. For this pursose, a case study on a planing is conducted. To collect data, interviews with employees from different departments have been made along with literature studies. The study presents that there are many challenges for the fluctuation demand such as lack of forecasts and lack of communication with customers. This, in turn, will cause problems with planning of the raw material as well as difficulties to deliver the goods on time.   The conclusion shows that the factors affecting a fluctuating demand are price variations, the orders batch size and order frequency. Price variations can be improved by ABC classification of the products by product demand. Forecasts will make the estimation of demand easier, although, in order to use forecasts properly a joint vision, close relationships and good communication with customer and supplier is required. Problems regarding batch size and order frequency can be reduced if the customer is allowed to decide the batch size with no specific requirements. The study also shows that factors such as weather, trends, fashion, holidays and disappearance of ROT work affects the fluctuating demand.

Dans cette thèse, nous nous sommes intéressés au mode d’exploitation de la demande prévisionnelle pour le pilotage des flux amont dans un contexte de production de masse de produits fortement diversifiés et de dispersion géographique des unités de production. Lorsque l’information prévisionnelle est mal exploitée, des phénomènes, similaires à l’effet coup de fouet connu en chaîne logistique aval, apparaissent en chaîne logistique amont altérant durablement sa performance. Dans le but de contrer certains des mécanismes à l’origine de ces phénomènes, nous avons proposé une adaptation de la MRP permettant d’exploiter au mieux l’information prévisionnelle. L’adaptation de la MRP repose sur une méthode de calcul des besoins basée sur l’exploitation statistique des nomenclatures de planification et la diffusion d’informations sur les niveaux de recomplètement le long de la chaîne logistique amont. Cette approche a été testée avec succès sur plusieurs cas d’application dans l’industrie automobile / In this PhD dissertation, we investigated the way of exploiting the demand forecasts for the upstream flow management in a context of mass production of highly diverse products and of geographical dispersion of the production units. When the forecasts are poorly exploited, phenomena similar to the well-known bullwhip effect in the downstream supply chain appear in the upstream supply chain altering permanently its performances. In order to counter some of the mechanisms underlying these phenomena, we proposed an adaptation of the MRP to perform the exploitation of the forecasted demand. The adaptation of the MRP is based on a calculation method that uses the planning BOM for calculating and transmitting replenishment levels along the upstream supply chain. This approach has been successfully tested on several application studies in the automotive industry

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.