Дисертації з теми "Optimal inventory management"

Companies dependent on commodities for their production have to deal with volatile commodity prices and should employ measures for risk reduction as unfavourable spot price development may cause significant losses. A useful tool for diminishing the risk is hedging on futures market; however, this approach faces a crucial question of optimal hedge ratio determination (ratio between spot and futures units). Our thesis examines nine different ways of optimal hedge ratio estimation (naive, Sharpe, mean extended Gini coefficient, generalized semivariance, value at risk, and minimum variance through OLS, error correction, GARCH, and bivariate GARCH models) and evaluates their efficiency using the data on eight different commodities. The results differ across the respective commodities and cannot be generalized. Two conclusions resulting from the analysis refer to performance of naive and OLS hedge ratios and constant vs time varying hedge ratios. We find that complex hedge ratios, such as bivariate GARCH or VaR hedge ratios, do not outperform naive and OLS hedge ratios and that the results of constant hedge ratios are mostly as good as results of time-varying hedge ratios.

Thesis: M. Eng. in Supply Chain Management, Massachusetts Institute of Technology, Supply Chain Management Program, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 52-53).
While festivals bring a reason to cheer for everyone, businesses dealing with a spike in demand for perishables may have to live with the misery of lost sales and/or expired items. In the case of the dairy industry that deals with liquid milk, both raw material, and finished goods are perishable, which implies that merely stockpiling inventory of either item, without paying attention to potential inventory losses, cannot be an optimal strategy. In developing countries, the supplier base for perishables like milk, fruits, vegetables, flowers, etc. mostly comprise of small farmers instead of corporate/professional agencies, thus leading to supply variability. During special occasions like festivals, as individuals set aside more of the raw material for their own consumption, we encounter a reduction in supply. Around the same time, we notice a spike in customer demand, leading to a demand-supply mismatch. Companies dealing with perishables need an analytical approach to manage this.
In this thesis, we present a framework to address this problem of intermittent demand-supply mismatch using a 3-stage stochastic optimization model. We decide on the sourcing targets, the production plans based on supply realized, and finally, the dispatch plan based on orders received. As a case study, we analyze the operations and data from a private dairy company in eastern India, to understand the research problem and the applicability of the resulting model. We notice the impact of demand spikes and supply reduction in two areas: we increase supply targets in the periods preceding the demand spike; and we increase supply targets in periods when supply is expected to decrease, while demand is as usual. When there are multiple festival days within the time series, the compounding of impact depends on the sequencing of the events.
Finally, when we introduce the realistic constraint that the supply target needs to be constant throughout the time series, we see a degradation in the profitability, as we need to tradeoff between lost sales and wasted products. While the focus of this case study is the dairy industry, the conclusions from this research are broadly applicable to other industries dealing with perishables.
by Vishwanathan Parameshwaran lyer Nurani.
M. Eng. in Supply Chain Management
M.Eng.inSupplyChainManagement Massachusetts Institute of Technology, Supply Chain Management Program

Diese Dissertation analysiert das optimale Zusammenspiel dynamischer Preissetzung, dynamischer Werbung und Bestandsmanagement. Wir betrachten verschiedene Optimierungsprobleme für einen monopolistischen Händler bei gegebener zeitabhängiger deterministischer Nachfrage. In Kapitel 2 erweitern wir das Modell von Rajan et al. (1992). Der Händler darf einen dynamischen Preis, eine dynamische Werberate und die Lagergröße bei fester Verkaufsdauer wählen, so dass der Barwert von Umsatz minus Lager-, Einkaufs- und (nichtlinearen) Werbekosten maximiert wird; zusätzlich zerfällt der Lagerbestand mit exponentieller Rate. Wir ermitteln die optimale Preis-Werbe-Steuerung und die optimale Lagergröße und betrachten auch semi-statische Situationen. Wir führen eine Sensitivitätsanalyse im Hinblick auf den Einfluss der Modellparameter auf die optimalen Ergebnisse durch und vergleichen die Ergebnisse des dynamischen Modells mit denen der semi-statischen Modelle. In Kapitel 3 interpretieren wir den Verkaufsprozess als gesteuerten Diffusionsprozess eines neuen Produktes und die Lagergröße als unerschlossenen Marktanteil. Der Anfangszustand ist exogen gegeben und die Nachfrage hängt zusätzlich vom gegenwärtigen Zustand des Systems ab. Ein Zerfall des Lagerbestandes und alle Kosten bis auf Werbekosten sind ausgenommen. Anders als in Helmes et al. (2013) leiten wir die optimale Steuerung mithilfe des Pontrjaginschen Maximumprinzips her. Als Anwendung betrachten wir das Modell von von Bertalanffy. In Kapitel 4 erweitern wir die Analyse von einperiodigen Modellen auf langfristige Modelle. Die Länge des Verkaufszyklus und die Lagergröße sind Entscheidungsvariablen, wobei die optimalen Steuerungen aus Kapitel 2 bzw. Kapitel 3 während eines Zyklus angewandt werden. Existenzbedingungen für ein optimales Paar aus Zykluslänge und Lagergröße werden hergeleitet. Wir analysieren verschiedene Anwendungs- und Illustrationsbeispiele und verifizieren Strukturaussagen der optimalen Entscheidungsgrößen.
This dissertation analyzes the optimal coordination of dynamic pricing, dynamic advertising, and inventory management. We consider different optimization problems for a monopolistic retailer who faces a time-dependent deterministic demand. In Chapter 2, we generalize the model of Rajan et al. (1992). The retailer is allowed to choose a dynamic price, a dynamic advertising rate, and the inventory capacity for a sales period of fixed length so that the present value of revenue minus inventory, purchasing and (nonlinear) advertising costs is maximized; in addition, the inventory deteriorates at an exponential rate. We derive the optimal dynamic price-advertising control and the optimal capacity and also consider partially static cases. For the optimally controlled dynamic model we carry out a sensitivity analysis with respect to the model parameters and we compare the results of the dynamic model with those of the partially static models. In Chapter 3, we interpret the sales process as the controlled adoption process of a new product and the inventory capacity as untapped market share. The initial state is assumed to be exogenously given and the demand depends on the current state of the system. We exclude, however, deterioration effects and any other costs but the cost of advertising. We derive the optimal controls using a different technique than Helmes et al. (2013) - we apply Pontryagin’s maximum principle. As an interesting application we consider the controlled von Bertalanffy model. In Chapter 4, we extend the analysis of one-period models to multi-period and longterm average models. Assuming that the optimal controls derived in Chapter 2 and Chapter 3 are applied throughout a cycle, we treat the cycle length and the capacity as decision variables. We derive conditions that ensure the existence of an optimal pair of cycle length and capacity. Various examples and illustrations are given, and structural properties of the optimal pair are verified.

Inventory management and production control problem of a dealer operating in a decentralized spare parts network is analyzed in this dissertation. Spare parts network is assumed to be formed of two dealers and the problem of a dealer is considered under the assumption that the other dealer has a known policy. These dealers collaborate through inventory and service pooling. Furthermore, the dealers collaborate through sharing information on the net inventory status. Upon demand arrival, a dealer may request a part from the other dealer, in which case a payment is made. Under this competitive and collaborative environment, the optimal operating policy of an individual dealer is characterized under full information. Through computational analysis, the conditions under which the dealer under consideration is most profitable are identified. Finally, by comparing dierent pooling strategies and several information availability levels, the benefit of information sharing is quantified.

La presente tesis tiene como objetivo identificar si existe correlación alguna entre los costos evitables en operaciones de importación marítima y la prestación de nivel de servicio mostrando resultados sobre la implementación realizada en una de las principales empresas en el rubro de importación y distribución de equipamiento gastronómico profesional de la ciudad de Lima. Luego de realizar la implementación aprobada para el 2017, los costos evitables en operaciones de importación marítima fueron reducidos en un 13.85% con respecto al periodo anterior. Se demostró que los costos evitables (r=0.75) tiene una relación alta y positiva con el nivel de servicio, es decir que a medida que se disminuyan y la empresa deje de asumir estos podrá ser mejor su nivel de servicio. Para la presentación se tiene una estructura de cinco capítulos: En el primer capítulo, el marco teórico, se detalló conceptos relacionados a los costos evitables en operación de importación marítima, nivel de servicio, cantidad óptima a ordenar, inventario de seguridad, punto de reorden y costos totales de gestión de inventarios. Además, se mostró información sobre la empresa donde se implementaron las mejoras. En el segundo capítulo, se explicó temas en relación al plan de investigación, dando a conocer el problema, la formulación de la hipótesis, el objetivo general y los específicos. En el tercer capítulo, se trató la metodología de la investigación, donde se determinó el enfoque y diseño, la población, la definición de variables y la recolección de datos. En el cuarto capítulo, se desarrolló la investigación calculando los costos evitables en 3 niveles de servicio. Se estableció dos escenarios (con costos evitables y sin costos evitables) a los sub-variables niveles de servicio, cantidad óptima a ordenar, inventario de seguridad, punto de reorden y costos totales de gestión de inventarios. Finalmente, en el quinto capítulo se mostró el análisis de resultados respondiendo al problema si existe correlación entre los costos evitables en operación de importación marítima y la prestación de nivel de servicio, y brindaremos conclusiones y las recomendaciones sobre la investigación desarrollada.
The objective of this thesis is to identify if there is any correlation between the avoidable costs in maritime import operations and the level of service provision, showing results on the implementation carried out in one of the main companies in the import and distribution of professional gastronomic equipment category from the city of Lima. After implementing the approved implementation for 2017, avoidable costs in maritime import operations were reduced by 13.85% compared to the previous period. It was shown that the avoidable costs (r = 0.75) has a high and positive relationship with the service level, that is to say that as they decrease and the company stops assuming these, their level of service may be better. For the presentation there is a structure of five chapters: In the first chapter, the theoretical framework, detailed concepts related to avoidable costs in maritime import operation, service level, optimal quantity to order, safety inventory, reorder point and total inventory management costs. In addition, information was shown about the company where the improvements were implemented. In the second chapter, topics were explained in relation to the research plan, making known the problem, the formulation of the hypothesis, the general objective and the specific ones. In the third chapter, the methodology of the research was discussed, where the approach and design, the population, the definition of variables and the data collection were determined. In the fourth chapter, the research was developed calculating avoidable costs in 3 levels of service. Two scenarios were established (with avoidable costs and no avoidable costs) to the sub-variables service levels, optimal quantity to be ordered, security inventory, reorder point and total inventory management costs. Finally, the fifth chapter showed the analysis of results answering the problem if there is a correlation between the avoidable costs in maritime import operation and the level of service provision, and we will provide conclusions and recommendations on the research developed.
Tesis

Nous analysons un type W de système de l’Assemble-à-commande avec des délais de livraison aléatoires, l'arrivée aléatoire de la demande et des ventes perdues, en temps continu. Nous formulons le problème en tant que processus de décision Markov à l'horizon infini. Nous nous éloignons de l'approche standard en caractérisant une région de l'espace d'état où toutes les propriétés de la fonction de coût tiennent. Nous caractérisons la politique optimale dans cette région. En particulier, nous montrons que, dans l'intérieur de la région récurrente, les composants sont toujours produits. Nous caractérisons également la politique d'allocation de composants optimale qui spécifie si une demande de produit arrivant devrait être remplie. Notre analyse révèle que la politique d'allocation optimale est contre-intuitive. Par exemple, même lorsqu'un produit domine l'autre, en termes de coût/taux de vente perdue, sa demande peut ne pas avoir une priorité absolue par rapport à la demande de l'autre produit. Une telle caractéristique n'a pas été observée dans de nombreux paramètres intégrés de production/inventaire où l'allocation d'inventaire suit une priorité fixe pour satisfaire les exigences. Nous montrons également que la structure de la politique optimale reste la même pour les systèmes à production par lots, les temps de production répartis par Erlang et la demande de produits non unitaire. Enfin, nous proposons des heuristiques efficaces qui peuvent être utilisées comme substitut à la politique optimale ou peuvent être utilisées comme une politique de départ pour les algorithmes communs utilisés pour obtenir une politique optimale dans le but de réduire leur temps de calcul
We analyze a W-configuration assemble-to-order system with random lead times, random arrival of demand, and lost sales, in continuous time. We formulate the problem as an infinite-horizon Markov decision process. We deviate from the standard approach by first characterizing a region (the recurrent region) of the state space where all properties of the cost function hold. We then characterize the optimal policy within this region. In particular, we show that within the interior of the recurrent region components are always produced. We also characterize the optimal component allocation policy which specifies whether an arriving product demand should be fulfilled. Our analysis reveals that the optimal allocation policy is counter-intuitive. For instance, even when one product dominates the other, in terms of lost sale cost and lost sale cost rate (i.e., demand rate times the lost sale cost), its demand may not have absolute priority over the other product’s demand. Such a feature has not been observed in many integrated production/inventory settings where inventory allocation follows a fixed priority in satisfying demands. We also show that the structure of the optimal policy remains the same for systems with batch production, Erlang distributed production times, and non-unitary product demand. Finally, we propose efficient heuristics that can be either used as a substitute for the optimal policy or can be used as a starting policy for the common algorithms that are used to obtain the optimal policy in an effort to reduce their computational time

Spatial and temporal information on catchment sediment sources and sinks can provide an improved understanding of catchment response to human-induced disturbances. This is essential for the implementation of well-targeted catchment-management decisions. This thesis investigates the nature and timing of catchment response to human activities by examining changes in sediment sources and sinks in a dry-tropical subcatchment of the Great Barrier Reef (GBR) catchment area, in northeastern Australia. Changes in catchment sediment sources, both in terms of spatial provenance and erosion type, are determined using sediment tracing techniques. Results indicate that changes in sediment source contributions over the last 250 years can be linked directly to changes in catchment land use. Sheetwash and rill erosion from cultivated land (40-60%) and channel erosion from grazed areas (30-80%) currently contribute most sediment to the river system. Channel erosion, on a basin-wide scale, appears to be more important than previously considered in this region of Australia. Optically stimulated luminescence and 137Cs dating are used to determine pre-and post- European settlement (ca. 1850) alluvial sedimentation rates. The limitations of using 137Cs as a floodplain sediment dating tool in a low fallout environment, dominated by sediment derived from channel and cultivation sources, are identified. Low magnitude increases in post-disturbance floodplain sedimentation rates (3 to 4 times) are attributed to the naturally high sediment loads in the dry-tropics. These low increases suggest that previous predictions which reflect order of magnitude increases in post-disturbance sediment yields are likely to be overestimates. In-channel bench deposits, formed since European settlement, are common features that appear to be important stores of recently eroded material. The spatially distributed erosion/sediment yield model SedNet is applied, both with generic input parameters and locally-derived data. Outputs are evaluated against available empirically-derived data. The results suggest that previous model estimates using generic input parameters overestimate post-disturbance and underestimate predisturbance sediment yields, exaggerating the impact of European catchment disturbance. This is likely to have important implications for both local-scale and catchment-wide management scenarios in the GBR region. Suggestions for future study and the collection of important empirical data to enable more accurate model performance are made.

The dissertation contains two major research projects. In the first project, we first study a multi-period inventory planning problem. In each period, the firm under consideration can source from two possibly unreliable suppliers for a price-dependent demand. Our analysis suggests that the optimal procurement policy is neither a simple reorder-point policy nor a complex one without any structure, as previous studies suggest. Instead, we prove the existence of a reorder point for each supplier. No order is placed to that supplier for any inventory level above the reorder point and a positive order is issued to that supplier for almost every inventory level below the reorder point. We characterize conditions under which the optimal policy reveals monotone response to changes in the inventory level. Furthermore, two special cases of our model are examined in detail to demonstrate how our analysis generalizes a number of well-known results in the literature. In the second project, we study a long-run inventory planning problem in which the retailer can replenish inventory and change price adjustment. We establish that it is optimal to change the price from low to high in each replenishment cycle, the optimal order-up-to level may decrease when the ordering cost increases, and fewer customers are served when the unit cost of procurement increases. Additionally, we provide efficient algorithms to compute the optimal stocking and pricing policies.
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碩士
國立中央大學
工業管理研究所
98
In recent years, stores in internet have become one of the channels of buying goods so there are more and more internet stores open and compete with each other intensely. Amazon is the biggest internet store in the world at the present day. It has more competitive than other rivals because of its good operating and managing way. This research considers centralized and decentralized store which is divided two parts by a single retailer (Amazon) and a single vendor. On the decentralized store channel, the retailer decides the price of the product first, and then Amazon decides the ratio of the revenue sharing. After selling the product, the retailer deducts a percentage from the selling price and remits the balance to the supplier. However, on the centralized store channel, they decide the price together. Part one discusses Amazon’s operation way and management. In the operation part, we discuss the website’s running way and situation and where it built its warehouses. In the management part, we discuss Amazon’s inventory, logistics and supply chain management deeply. We also discuss the fee structures of Amazon’s store and auction market. Part two discusses Amazon’s channel model. We divide its channel into centralized and decentralized by the decision maker and method. The demand models are decided or indefinite in these two kinds of model. This research discusses the revenue of the whole channel, Amazon or the vendor in four situations and the optimal price and revenue sharing portion of the central and decentralized channel under the revenue sharing contract. This research shows that the optimal price of the central channel is lower than the optimal price of the decentralized channel. The optimal revenue of the centralized channel is larger than the sum of the supplier’s and Amazon’s revenue of the decentralized channel.

Yu, Yikun.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (p. 117-120).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Literature Review --- p.6
Chapter 3 --- System with Controllable Returns --- p.13
Chapter 3.1 --- Problem Description --- p.13
Chapter 3.2 --- The Model with Controllable Returns --- p.17
Chapter 3.3 --- Numerical Experiments --- p.25
Chapter 3.4 --- Summary --- p.34
Chapter 4 --- System with Controllable Returns and Price Dependent Demand --- p.36
Chapter 4.1 --- System without Disposals --- p.37
Chapter 4.2 --- The System with Disposals --- p.40
Chapter 4.3 --- Numerical Experiments --- p.47
Chapter 4.4 --- Summary --- p.54
Chapter 5 --- Conclusion --- p.56
Chapter 6 --- Appendix --- p.58

In this thesis, we study the statistical issues in lost sales inventory systems, focusing on the complexity arising from the stochastic demand. We model the demand by the Zero Inflated Poisson (ZIP) distribution. The maximum likelihood estimator of the ZIP parameters taking censoring into account are derived separately for the newsvendor and the (s, S) inventory systems. We also investigate the effect of the estimation errors on the optimal policies and their costs. We observe from a simulation study that the MLE taking censoring into account performed the best in terms of cost as well as policy among various estimates. We then proceed to develop a Bayesian dynamic updating scheme of the ZIP parameters. It is applied to the newsvendor system. We perform a simulation study to investigate the advantage of the Bayesian updating approach over the traditional MLE approach. We conclude that the Bayesian pproach offers a better learning technique when one lacks of good understanding of the demand pattern in the first few periods. Since inventory policy affects the information acquisition and-the demand distribution updating process, how to determine the optimal inventory policy when the demand distribution is yet to be learned is the focus of the latter part of the thesis. We investigate the effect of demand censoring on the optimal policy in newsvendor inventory models with general parametric demand distribution and unknown parameter values. We provide theoretical proof of the conjecture that it is better off to adopt a higher than the myopic optimal policy in the initial periods when demand is learned in a censoring system. We show that the newsvendor problem with observable lost sales reduces to a sequence of single-period problems while the newsvendor problem with unobservable lost sales requires a dynamic analysis. We explore the economic rationality for this observation and illustrate it with numerical examples.

博士
中原大學
應用數學研究所
98
The traditional EPQ (Economic Production Quantity) model assumes that the replenishments of raw materials are instantaneous. In practical, business enterprises buy all of the raw materials what they need at the beginning of a cycle time. So, the stock holding cost of raw materials should be counted into the total relevant costs. Besides, on the concept of financial analysis, the managers need to use the concept of time value of money to calculate the present value at same time to compare different cases. In recent years, because of the competition in market and the rapid revision of products , the cycle length of products become shorten and given up.In this research, we assume that in the condition of buying all of the materials at the beginning of a cycle time. First of all, we discuss the inventory model of considering the time value of money in the infinite planning horizon. And then develop the EPQ model to a random planning horizon and then find the present value of the model. Finally, we calculate the present value that does not the salvage of remnant inventories into consideration under a random planning horizon. From above three different models, we minimize the total relevant costs to find the optimal cycle time and numerical examples are included to prove the results in models.

博士
中原大學
應用數學研究所
101
ABSTRACT The traditional Economic Production Quantity (EPQ) assumes that the replenishments are instantaneous and the relevant cost only consists of setup cost, stock-holding cost of the finished goods and the purchasing cost of raw materials. To be a manager of a manufactory, one more issue that must be taken into consideration is the stock-holding cost of raw materials. Suppose all of the raw materials were bought at the beginning, the stock-holding cost for the raw materials would be generated. Regarding the factor, the stock-holding cost of raw material should be accounted into the relevant cost. The main concept of this research is to put the stock-holding cost of raw materials in the EPQ model. Based on this concept, we develop the new inventory models and the corresponding optimal policies. There are some more elements will be considered for the EPQ models, they are described as follows: time value, deteriorating items, imperfect quality items, random planning horizon. The models will be useful and practical. Environmental protection issues have been eagerly discussed and concerned in recent years, and they will still be in the years to come. To deal with these problems, the reusable raw materials are tented to replace the new raw materials to reduce the impact on the environment and increase the competition for business. Therefore most of the models are based on using reusable raw materials to find the optimal relevant cost. The upper and lower bounds are determined in this research in order to develop an algorithm used to compute the optimal cycle time. The analysis brings numerical examples into the algorithm in order to find the different cycle times. This research shows how the model is useful for current and future research. Keywords: Inventory, Economic Production Quantity (EPQ), raw materials,reusable, imperfect quality items, deteriorating items, present value, random planning horizon

Transportation is important in making supply chain decisions. With the careful consideration of transportation expenses, the performance of each supply chain member, as well as the entire supply chain, could be improved significantly. The purpose of this research is: 1) to explore and identify the various situations that relate to replenishment and transportation activities; and 2) to reveal the strength of the connection between purchase quantity and transportation discounts, and integrate the two discounts to enhance supply-chain coordination. The problem is analyzed and categorized into four representative cases, depending on transportation. To aid the supplier or the carrier to determine the discount that should be offered, in light of the buyer's reaction to that discount, decision models are proposed under three different circumstances. First, assuming a single product, we investigate the quantity discounts from the supplier's perspective, via a noncooperative game-theoretical approach and also a joint decision model. Taking into account the price elasticity of demand, this analysis aids a sole supplier in establishing an all-unit quantity discount policy in light of the buyer's best reaction. The Stackelberg equilibrium and the Pareto-optimal solution set are derived for the noncooperative and joint-decision cases, respectively. Our research indicates that channel efficiency can be improved significantly if the quantity discount decision is made jointly rather than noncooperatively. Moreover, we extend our model in several directions: (a) the product is transported by a private fleet; (b) the buyer may choose to offer her customers a different percentage discount than that she obtained from the supplier; and (c) the case of multiple (heterogeneous) buyers. Numerical examples are employed, here and throughout the thesis, to illustrate the practical applications of the models presented and the sensitivity to model parameters. Secondly, we consider a situation with a family of SKUs for which the supplier will offer a quantity discount, according to the aggregate purchases of the product group. Management of those items is based on the modified periodic policy. From the supplier's point of view, what are the optimal parameters (breakpoint and discount percentage)? For deterministic demand, we discuss the cases in which demand is both constant and price-sensitive. First as a noncooperative Stackelberg game, and then when the two parties make the discount and replenishment decisions jointly, we illustrate the impact of price-sensitivity and joint decision making on the supplier's discount policy. The third approach studies the case in which transportation of the goods by a common carrier (a public, for-hire trucking company) is integrated in the quantity discount decisions. In reality, it is quite difficult for the carrier to determine the proper transportation discount, especially in the case of LTL (less-than-truckload) trucking. This is not only because of the "phantom freight" phenomenon, caused by possible over-declaration of the weight by the shipper, but also due to the fact that the discount relates to both transportation and inventory issues. In this research, we study the problem of coordinating the transportation and quantity discount decisions from the perspectives of the parties who offer the discounts, rather than the ones that take them. By comparison of the noncooperative and cooperative models, we show that cooperation provides better overall results, not only to each party, but also to the entire supply chain. To divide the extra payoffs gained from that cooperation, we further conduct a coalition analysis, based upon the concept of "Shapley Value." A detailed algorithm and numerical examples are provided to illustrate the solution procedure. Finally, the thesis concludes with comprehensive remarks. We summarize the contributions of this thesis, show the overall results obtained here, and present the directions that our research may take in the future.

碩士
東海大學
工業工程與經營資訊學系
97
This study focus on the re-engineering of Tube-Feeding-Diet (TFD) operation processes and inventory management in the Nutrition Department in a Medical Center. After conducting careful analysis, we found many problems including inappropriate design of the existing tables and sheets, improper operations in the processes, no discarding procedure was designated and no statistical sheets are available for the managers, etc. In order to solve the above problems, we propose a series of eight-step action items: (1) Design new tables and sheets to replace the inappropriate ones in the TFD service operation processes. (2) Modify the design of the diet-change order sheet and change the operation processes. (3) Replace the existing diet-sheet with a new self-sticking label accompanying with a new design that shows clear and necessary information. (4) Introduce new catering tables and sheets to replace the existing ones. (5) A discarding procedure is proposed for the TFD service operation processes. (6)Re-design the replenishment operation procedure for canned TFD items in Building No.2. (7) Set up an inventory auditing procedures for the TFD items in the preparation room in Building No.1 and the storage room in Building No.2. (8) Establish a new web-based information system to assist the Nutrition Department in the TFD service operation processes. Following cautious assessment, the Nutrition Department not only is able to solve the problems using the six proposed action items, but also secure a cost-saving of $NTD 40,000 each month. To control the inventory of the TFD items, the managers are desperate for a systematic infrastructure and more efficient approaches for optimal purchasing policy derivation. For each category of the TFD items, we employ a mathematical model for obtaining an optimal purchasing policy so as to minimize the total inventory costs per unit time. This study proposes the managers in TCVGH a useful decision support system to significantly improve the efficiency of the operations of the TFD items by reducing the inventory costs and improving the replenishment processes from the suppliers.