Event-Driven Network Model for Space Mission Optimization with High-Thrust and Low-Thrust Spacecraft

Numerous high-thrust and low-thrust space propulsion technologies have been developed in the recent years with the goal of expanding space exploration capabilities; however, designing and optimizing a multi-mission campaign with both high-thrust and low-thrust propulsion options are challenging due to the coupling between logistics mission design and trajectory evaluation. Specifically, this computational burden arises because the deliverable mass fraction (i.e., final-to-initial mass ratio) and time of flight for low-thrust trajectories can can vary with the payload mass; thus, these trajectory metrics cannot be evaluated separately from the campaign-level mission design. To tackle this challenge, this paper develops a novel event-driven space logistics network optimization approach using mixed-integer linear programming for space campaign design. An example case of optimally designing a cislunar propellant supply chain to support multiple lunar surface access missions is used to demonstrate this new space logistics framework. The results are compared with an existing stochastic combinatorial formulation developed for incorporating low-thrust propulsion into space logistics design; our new approach provides superior results in terms of cost as well as utilization of the vehicle fleet. The event-driven space logistics network optimization method developed in this paper can trade off cost, time, and technology in an automated manner to optimally design space mission campaigns.Comment: 38 pages; 11 figures; Journal of Spacecraft and Rockets (Accepted); previous version presented at the AAS/AIAA Astrodynamics Specialist Conference, 201

A Decision Making Framework for Reverse Logistics Network Design

The main objective of this research is to answer the following research question “How should a company design their reverse logistics network in a more efficient or responsive way?” In this research, a conceptual framework has been developed based on several key factors for network design. Through the analysis of each key factor affecting network design decision, we have built a conceptual framework for reverse logistics network for companies to decide on whether to centralize versus decentralize their reverse logistics operations, and whether to outsource or insource some of their operations? Some existing studies are able to fit well in our proposed framework, giving us better insights to decision making in reverse logistics network design. The proposed conceptual framework is helpful for the companies or organizations to make better decisions when designing their reverse logistics operations to achieve a lean or responsive network

Reverse Logistics Network Structures and Design

Logistics network design is commonly recognized as a strategic supply chain issue of prime importance. The location of production facilities, storage concepts, and transportation strategies are major determinants of supply chain performance. This chapter considers logistics network design for the particular case of closed-loop supply chains. We highlight key issues that companies are facing when deciding upon the logistics implementation of a product recovery initiative. In particular, we point out differences and analogies with logistics network design for traditional 'forward' supply chains. Moreover, we discuss the strategic fit between specific supply chain contexts and logistics network structures. Conclusions are supported by a quantitative analysis

Dataset of the Refrigerator Case: design of closed loop supply chains

This paper contains the dataset for the refrigerator case concerning the design of a production and return network for refrigerators. Section 1 emphasises the major changes to the problem structure and assumptions used by Umeda et al. (1999). Section 2 contains the parameter settings. Section 3 contains the distance matrix for all locations.supply chain management;reverse logistics;facility location;network design;product design

Design of Closed Loop Supply Chains

Increased concern for the environment has lead to new techniques to design products and supply chains that are both economically and ecologically feasible. This paper deals with the product - and corresponding supply chain design for a refrigerator. Literature study shows that there are many models to support product design and logistics separately, but not in an integrated way. In our research we develop quantitative modelling to support an optimal design structure of a product, i.e. modularity, repairability, recyclability, as well as the optimal locations and goods flows allocation in the logistics system. Environmental impacts are measured by energy and waste. Economic costs are modelled as linear functions of volumes with a fixed set-up component for facilities. We apply this model using real life R&D data of a Japanese consumer electronics company. The model is run for different scenarios using different parameter settings such as centralised versus decentralised logistics, alternative product designs, varying return quality and quantity, and potential environmental legislation based on producer responsibility.supply chain management;reverse logistics;facility location;network design;product design

Design of a Third-party Reverse Logistics Network under a Carbon Tax Scheme

© 2016 Eastern Macedonia and Thrace Institute of Technology. Reverse logistics network involves significant inherent uncertainties, which cannot be completely characterized because of a lack of adequate historical data. In this study, a multi-product and multi-period interval programming model was developed on the basis of partial information to design an effective reverse logistics network. In addition, the trade-offbetween economic benefits and the environmental burdens from carbon emissions was analyzed by considering the effect of a carbon tax scheme on the reverse logistics network design. Through an improved and modified interval linear programming method, the optimal interval solution was obtained with LINGO. Finally, numerical simulations were conducted to explore the effectiveness of the model and the effect of the carbon tax scheme. Results show that the optimal solution of the reverse logistics network design is robust. The effect of the carbon tax scheme is trivial when the carbon tax is low and significant when the carbon tax is high. As carbon tax gradually increases, carbon emissions effectively decrease, but sharply declines the total profit sharply declines. The findings indicate that the proposed model can effectively solve the reverse logistics network design with partial information under a carbon tax scheme

Linear integrated location-inventory models for service parts logistics network design

We present two integrated network design and inventory control problems in service-parts logistics systems. Such models are complicated due to demand uncertainty and highly nonlinear time-based service level constraints. Exploiting unique properties of the nonlinear constraints, we provide an equivalent linear formulation under part-warehouse service requirements, and an approximate linear formulation under part service requirements. Computational results indicate the superiority of our approach over existing approaches in the literature

Congestion pricing and network expansion

Over the past decade network industries (such as gas, electricity, and telecommunications) have undergone a dramatic transformation. Competition has been introduced in industries that had long been viewed as textbook examples of natural monopolies. Production and transport have been unbundled to foster the introduction of competition: the capacity provider (the owner of the infrastructure) now often differs from the service provider. Chief among the challenges this raises for economists and policymakers: to design institutions that lead to"optimal"network expansion. Different arrangements have been suggested, ranging from indicative planning to decentralization of investment decisions through congestion pricing. Two questions lie at the core of the debate: Is the infrastructure network still a natural monopoly? And what role should congestion pricing play in ensuring optimal network expansion? The author shows that simple economic principles apply to the use of congestion pricing to induce network expansion: a) If network provision is competitive, congestion pricing leads to optimal investment. b) If network provision is monopolistic, congestion pricing leads to underinvestment. He shows the model applying to power networks as well as to the Internet. Policymakers must therefore assess whether network expansion is indeed competitive and design institutions that ease entry, or design an appropriate regulatory framework.Banks&Banking Reform,Economic Theory&Research,Common Carriers Industry,Transport and Trade Logistics,Markets and Market Access,Common Carriers Industry,Economic Theory&Research,Geographical Information Systems,Banks&Banking Reform,Transport and Trade Logistics