Yue Jin Researcher Member of Technical Staff Bell Labs Ireland Telephone: +353-1-88-64664 (o)                    +353-85-759-1016 (c) Fax: +353-1-88-64782 E-mail: yuejin@alcatel-lucent.com Curriculum Vitae

Research Interest

• Decentralized Decision Making I

  Decentralized decision making posts many interesting questions in front of us. Uncoordinated decentralized decision making system usually performs less efficiently than a centralized decision making system. Naturally one would like to coordinate the decentralized system to achieve the same perfomance as the centralized one. If the system is a consortium of self-intersted players, the first thing one needs to make sure is that each player is willing to take part in the coordination. One needs to make sure that the allocation of profit will make every player better off, comparing to the uncoordinated system. What would be the right allocation of profit? On the other hand, if the system has a principle who manages the system through a group of agents, some different questions emerge. First, the principle can decide the functionality of each agent, that is, what decision each agent gets to make. What would be the right allocation of decision power? Second, the sum of the awards the agents receive is not the total system profit. Neither is the sum of the costs the agents observe necessarily the total system cost. How should the awards and costs be allocated to each agent so that their objectives are aligned with the objective of the principle? There are also some questions common to decentralied decision making systems. The different players/agents obviously need to communicate with each other. What information should they exchange? What format should the information be exchanged in: for example, should the confidence interval of the forecast be sent to the supplier in addition to the point estimation? Should there be some well-defined protocols in the system? Also, each player/agent will keep track of the performance of others in the system as well as his own. What metrics should be in place at each player/agent to ensure good performance as well as to prevent any player/agent from gaming the system? To answer all these challenging questions, interdiscipline coordination is surely a must, including operations management, game theory, statistics, ect.

• Game Theory
• Statistics and Information Sharing
• Industrial Organization
• Mathematical Programming

Journal Publications

• "Single-Warehouse Multi-Retailer Inventory Systems with Full Truck-Load Shipments", under revision in Naval Research Logistics, with Ana Muriel. Abstract PDF

  We consider a multistage inventory system composed of a single warehouse that receives a single product from a single supplier and replenishes the inventory of n retailers through direct shipments. Fixed costs are incurred for each truck dispatched and all trucks have the same capacity limit. Costs are stationary, or more generally monotone as in Lippman (1969). Demands for the n retailers over a planning horizon of T periods are given. The objective is to find the shipment quantities over the planning horizon to satisfy all demands at minimum system-wide inventory and transportation costs without backlogging. Using the structural properties of optimal solutions, we develop (1) an O(T2) algorithm for the single-stage dynamic lot sizing problem; (2) an O(T3) algorithm for the case of a one-warehouse single-retailer system; and (3) a nested shortest-path algorithm for the one-warehouse multi-retailer problem that runs in polynomial time for a given number of retailers. To overcome the computational burden when the number of retailers is large, we propose aggregated and disaggregated Lagrangian decomposition methods that make use of the structural properties and the efficient single-stage algorithm. Computational experiments show the effectiveness of these algorithms and the gains associated with coordinated versus decentralized systems. Finally, we show that the decentralized solution is asymptotically optimal.

• "Optimal Ordering Policies with Convertible Lead Times", European Journal of Operational Research, 176 (2), 892-910, Jan 2007, with G. Gallego, A. Muriel, G. Zhang and V.T. Yildiz. Abstract

  A firm receives orders that will be required at an uncertain time given by an Erlang distribution, and over time observes the associated independent exponential events. The firm, in turn, places orders at a linear cost from a supplier with fixed lead time l and has the option of converting (expediting) each order, at a cost, over a certain time interval after the order is originally placed. A converted order arrives le < l units of time after it is converted. We show that a threshold policy is optimal. Under such a policy the firm places an order after a certain number of exponential events have been observed. An order is converted the first time, if any, when the residual lead time exceeds a time threshold related to the number of exponential events realized since the order was placed.

Please see Curriculum Vitae for conference publications

Work in Progress

• "Capacity-expandable Product Design for a Competitive Downstream Market", with Qiong Wang and Ulas Ozen
• "Price and Service Competition in an Outsourced Supply Chain", with Jennifer Ryan
• "On the Profitability of Remanufactured Products", with Ana Muriel and Yihao Lu. Abstract PDF

  We investigate the profitability of offering remanufactured products for a monopoly firm in a single period setting. We characterize a threshold for the remanufacturing cost below which it is optimal to offer remanufactured products, and focus on analyzing its dependence on the consumer profile. This analysis allows us to identify when it is customer segmentation, and not the cost difference, that drives the remanufacturing decision. That is, we find conditions under which it is optimal to offer remanufactured products even if they are as costly to produce as new products. Consequently, it becomes cost effective to substitute them and offer new products under the remanufactured label when the latter are scarce. These results are also applicable to the evaluation of the common marketing practices of branding, i.e, offering virtually identical products under different brands, and generics, i.e. offering generic versions of a landmark label.

• "Impact of the Quality and Cost of Information on the Reverse Supply Chain", with Erin Baker, Ana Muriel and Jeroen Vits. Abstract PDF

  We analyze the relation between the value captured from returned products and the amount of information available on product quality. We show that increased information accuracy may lead to a decrease in the proportion of product recycled; and investments in information acquisition technology may result in optimally lower accuracy overall.

Links

• Industrial Mathematics and Operations Research Department in Bell Labs
• Bell Labs
• Supply Chain Management Research Group in University of Massachusetts Amherst
• University of Massachusetts Amherst