On the inventory performance of demand forecasting methods of medical items in humanitarian operations

The inventory management of medical items in humanitarian operations is a challenging task due to the intermittent nature of their demand and long replenishment lead-times. While effective response to emergency results in inventory build-up which saves human lives, excess inventories could be intentionally burnt or donated which is costly for humanitarian organizations. Henceforth, linking demand forecasting to the inventory control task is shown to be a significant scope to offer a higher performance. In this vein, it is key to accurately select adequate forecasting methods. This paper investigates the effectiveness of parametric and non-parametric demand forecasting methods that are commonly considered to deal with stock keeping units (SKUs) characterized with an intermittent demand in industrial contexts. To do so, we conduct an empirical study by means of data related to 1254 SKUs managed in three warehouses of a major humanitarian organization based in Geneva, Middle-east and Africa. The investigation is carried out to compare the inventory performance of three parametric and two bootstrapping methods when used with an order-up-to-level inventory control policy. The results demonstrate the high performance of the bootstrapping methods in achieving higher service levels. The investigation enables to gain insights on the forecasting method that should be selected under particular assumptions on the demand and the lead-time value

Prediction of U.S. General Aviation fatalities from extreme value approach

General Aviation is the main component of the United States civil aviation and the most aviation accidents concern this aviation category. Between early 2015 and May 17, 2016, a total of 1546 general aviation accidents in the United States has left 466 fatalities and 384 injured. Hence, in this study, we investigate the risk of U.S. General Aviation accidents by examining historical U.S. General Aviation accidents. Using the Peak Over Threshold approach and Generalized Pareto Distribution, we predict the number of fatalities resulting in extreme GA accidents in the future operations. We use a graphical method and intensive parameters estimates to obtain the optimal range of the threshold. In order to assess the uncertainty in the inference and the accuracy of the results, we use the nonparametric bootstrap approach

An improved method for forecasting spare parts demand using extreme value theory

Inventory control for spare parts is essential for many organizations due to the trade-off between preventing high holding cost and stockouts. The lead time demand distribution plays a central role in inventory control. The estimation of this distribution is problematic as the spare part demand is often intermittent, and as a consequence often only a limited number of non-zero data points are available in practice. The well-known empirical method uses historical demand data to construct the lead time demand distribution. Although it performs reasonably well when service requirements are relatively low, it has difficulties in achieving high target service levels. In this paper, we improve the empirical method by applying extreme value theory to model the tail of the lead time demand distribution. To make the most out of a limited number of demand observations, we establish that extreme value theory can be applied to lead time demand periods computed over overlapping intervals. We consider two service levels: the expected waiting time and cycle service level. Our experiments show that our method improves the inventory performance compared to the empirical method and is competitive with the WSS method, Croston's method and SBA for a range of demand distributions

A study of contagion in global and local banking industries

This thesis investigates contagion risk for the global and local banking environment using three different distance to risk measures (distance to default - DD, distance to capital – DC and distance to inefficiency- DI). In order to achieve this goal, the research has been divided into three parts (each will have its own chapter) to study the contagion effect in the global and local market. In the first part (chapter 4), the thesis investigates the contagion effect among the top 20 countries of the world. The sample consists of 91 banks from 20 countries across the globe including all G8 and BRICS countries. A list of all these countries and their corresponding banks is included later. The sample also includes all the GSIB (Global systematically important banks) banks excluding Group BPCE of France (given that Group BPCE originated in year 2009 by merging Caisse nationale des caisses d'épargne and Banque fédérale des banques populaires). In the second part (chapter 5), the thesis examines the local contagion by studying the spill over among top 15 US states. The sample consist of four of the largest banks from each of the sample 15 US state. A list of these banks is attached in the sample description. In chapter 6, the thesis performs a spill over analysis using DD, DI and DC. In order to do so, the thesis has measured the systemic risk using distance to default, distance to inefficiency and distance to capital, which are introduced by the option pricing theory (Merton, 1976). These distance to risk methods are defined as the theoretical difference between the entity’s current and breakeven risk position (Distance to default is the difference between the current and default position; Distance to inefficiency is the difference between the current and inefficient position and distance to capital is the difference between the current and default capital threshold position). Any position lower then this distance to risk measures is considered undesirable for the entity. The study has calculated 2606 daily observations for each of the different distance to risk measures for each bank in the sample for approximately 10 financial years from 2006 to 2015. Then the thesis compute the probability of experiencing extreme shocks in these distance measures of contagion risk using extreme value threshold. This research categorizes these extreme shocks into sub groups for the first two parts and keep the extreme shock unchanged for the last part and examine the contagion risk ascending from the movement of these extreme systemic shocks all through the US and global baking environment using multinomial logistic regression model (MLM). Finally, in chapter 7, the thesis discussed a possible risk management framework based on findings of the previous chapters. It has taken all the banks and divided them into 4 tiers based on their spill over impact. The study suggests that any bank in the 1st tier of the short term or long-term contagion capacity table should be referred to a high degree of regulatory control to enforce not only better capital governance or liquidity requirement but to also enforce overall financial governance as they have a huge impact on the other financial institutions. For the banks in the second and third tier, the authority may adopt a more gradually enforceable governance control in lieu with the current practice and the last tier can do their business in the current regulation, as they pose no real threat to the other peers. At the end, the study also suggests a new generic risk management framework for financial institutions

Modelo integral de gestión de repuestos para mantenimiento, en empresas intensivas en uso de capital

Empresas intensivas en uso de capital, buscan garantizar la disponibilidad de sus equipos y evitar un paro operativo, para lograr el cumplimiento de sus compromisos de producción. Para el cumplimiento de este objetivo, estas empresas prevén bien sea redundancia de equipos o mantener cantidades considerables de repuestos en sus bodegas para la atención de mantenimientos. Sin embargo, esto tiene como consecuencia, considerables costos por capital inmovilizado en el caso de redundancia, y costos de abastecimiento, almacenamiento y obsolescencia en el caso de repuestos. Este trabajo de grado propone un modelo de gestión de repuestos y de segmentación, alineado a las estrategias de mantenimiento y de abastecimiento, que busca minimizar los costos de repuestos, y garantizar su disponibilidad para atención de mantenimientos, incluyendo los criterios de política de inventarios y de nivel de servicio requerido por mantenimiento. El trabajo, realiza un análisis de procesos y con la opinión de expertos de una empresa intensiva en uso de capital, contrasta la práctica empresarial con la literatura disponible, para desarrollar un modelo de gestión de repuestos de mantenimiento. En la práctica empresarial, se presenta ruptura entre los procesos de mantenimiento y gestión de inventarios por objetivos contrarios entre sí; y de la misma manera en la literatura disponible, el problema se ha estudiado desde la óptica del mantenimiento o de gestión de inventarios. Para la validación del modelo, se aplicó a casos de negocio de segmentos propuestos, verificándose su validez, aplicabilidad y beneficios en una empresa de transporte de crudo por oleoducto.Capital-Intensive companies seek to guarantee the availability of their equipment and avoid an operational stoppage to comply with their production commitments. For the fulfillment of this objective, these companies foresee either redundancy of equipment or maintain considerable quantities of spare parts in their warehouses for the attention of maintenance. However, as a consequence it has considerable costs for immobilized capital in the case of redundancy, and costs of supply, storage and obsolescence in the case of spare parts. This paper proposes a spare parts and segmentation management model, aligned to maintenance and sourcing strategies, which seeks to minimize spare parts costs, and guarantee their availability for servicing maintenance, including inventory policy criteria and the level of service required for maintenance. The study carries out an analysis of the processes and with the opinion of experts of a capital-intensive company, contrasts business practice with the available literature, to develop a maintenance spare parts management model. In business practice, there is a break between maintenance processes and inventory management for their opposite objectives; and in the same way in the available literature, the problem has been studied either from the standpoint of maintenance or inventory management. For the validation of the management model, it was applied to business cases of spare parts segments, verifying its validity, applicability and economic benefits in an oil pipeline company.Magíster en Ingeniería IndustrialMaestrí