A Monotone Approximate Dynamic Programming Approach for the Stochastic Scheduling, Allocation, and Inventory Replenishment Problem: Applications to Drone and Electric Vehicle Battery Swap Stations

There is a growing interest in using electric vehicles (EVs) and drones for many applications. However, battery-oriented issues, including range anxiety and battery degradation, impede adoption. Battery swap stations are one alternative to reduce these concerns that allow the swap of depleted for full batteries in minutes. We consider the problem of deriving actions at a battery swap station when explicitly considering the uncertain arrival of swap demand, battery degradation, and replacement. We model the operations at a battery swap station using a finite horizon Markov decision process model for the stochastic scheduling, allocation, and inventory replenishment problem (SAIRP), which determines when and how many batteries are charged, discharged, and replaced over time. We present theoretical proofs for the monotonicity of the value function and monotone structure of an optimal policy for special SAIRP cases. Because of the curses of dimensionality, we develop a new monotone approximate dynamic programming (ADP) method, which intelligently initializes a value function approximation using regression. In computational tests, we demonstrate the superior performance of the new regression-based monotone ADP method compared with exact methods and other monotone ADP methods. Furthermore, with the tests, we deduce policy insights for drone swap stations.

Implementación de la planificación estratégica para empresas del sector automotriz en la ciudad de Santo Domingo de los Tsáchilas, Ecuador: Caso Importadora de Autorepuestos Mendoza

La implementación de herramientas administrativas, tal como la planeación estratégica, permitió establecer directrices para un mayor conocimiento de la situación actual de la empresa, así como también, se identificaron las problemáticas y establecieron las metas a corto y largo plazo. De tal modo, la implementación de las etapas de la planificación estratégica a través de la formulación, implementación y evaluación, establecieron una orientación en cada uno de los puntos importantes de la institución, tales como el desarrollo de políticas de recuperación de cartera, proceso de reposición de inventario y llevar a cabo acciones que determinen el direccionamiento y foco estratégico de la empresa. La implementación de la estrategia a través del mapa estratégico, permitió identificar 11 objetivos multinivel direccionados dentro de la perspectiva financiera, cliente, procesos internos y crecimiento / aprendizaje, seguidamente se evaluó el nivel de cumplimiento de los objetivos implementados mediante el diseño del Balanced Scoredcard de 1er y 2do nivel, con ello dar cumplimiento a la visión general de la empresa. The implementation of administrative tools, such as strategic planning, establishing guidelines for a greater understanding of the current situation of the company, as well as identifying problems and establishing short and long-term goals. In this way, the implementation of the stages of strategic planning through the formulation, implementation and evaluation, established an orientation in each of the important points of the institution, such as the development of portfolio recovery policies, process of inventory replenishment and carry out actions that determine the direction and strategic focus of the company. The implementation of the strategy through the strategic map, found 11 multilevel objectives directed within the financial perspective, customer, internal processes and growth / learning, then the level of fulfillment of the implemented objectives was evaluated through the design of the Balanced Scoredcard of 1st and 2nd level, thereby complying with the general vision of the company.

Joint Inventory Replenishment Planning of an E-Commerce Distribution System with Distribution Centers at Producers’ Locations

In this study, joint inventory replenishment planning of an Alibaba distribution system is investigated, which contributes to the circular economy concept. The distribution system includes suppliers, central distribution centers, and front distribution centers. The total replenishment cost of the distribution system can be reduced by setting up distribution centers at producers’ locations (PDCs), which also helps to reduce the wastages of commodities during the transportation and CO2 emission released by transportation. The joint replenishments of multiple products are constrained by a maximum joint replenishment quantity. Trans-shipments happen among different distribution centers. The considered problem seeks to find the replenishment quantities of products among stocks, which can minimize the total replenishment cost of the system, and is formulated as a novel mathematical model. The effectiveness of our proposed model is validated by computational experiments based on Alibaba’s data. The results indicate that PDCs and trans-shipments can bring about lower replenishment costs if a common service level of the system is given.

Inventory classification system in space mission component replenishment using multi-attribute fuzzy ABC classification

PurposeThis project attempts to present a space component inventory classification system for space inventory replenishment and management. The authors propose to adopt a classification system that can incorporate all the different variables in a multi-criteria configuration. Fuzzy logic is applied as an effective way for formulating classification problems in space inventory replenishment.Design/methodology/approachA fuzzy-based approach with ABC classification is proposed to incorporate all the different variables in a multi-criteria configuration. Fuzzy logic is applied as an effective way for formulating classification problems in space inventory replenishment of the soil preparation system (SOPSYS) which is used in grinding and sifting Phobos rocks to sub-millimeter size in the Phobos-Grunt space mission. An information system was developed using the existing platform and was used to support the key aspects in performing inventory classification and purchasing optimization.FindingsThe proposed classification system was found to be able to classify the inventory and optimize the purchasing decision efficiency. Based on the information provided from the system, implementation plans for the SOPSYS project and related space projects can be proposed.Research limitations/implicationsThe paper addresses one of the main difficulties in handling qualitative or quantitative classification criteria. The model can be implemented using mathematical calculation tools and integrated into the existing inventory management system. The proposed model has important implications in optimizing the purchasing decisions to shorten the research and development of other space instruments in space missions.Originality/valueInventory management in the manufacture of space instruments is one of the major problems due to the complexity of the manufacturing process and the large variety of items. The classification system can optimize purchasing decision-making in the inventory management process. It is also designed to be flexible and can be implemented for the manufacture of other space mission instruments.