Showing papers by "Xueping Li published in 2010"

Impacts of supply disruptions and customer differentiation in a partial-backordering inventory system

Abstract: Abstract In this paper, we study a single-product inventory system which involves a supplier, a retailer, and differentiated customers. The supplier provides products to the retailer which in turn sells products to its customers. The supplier is unreliable and is subject to random disruptions. The retailer adopts a periodic-review inventory policy, under which the retailer reviews its inventory position every a fixed period of time and decides whether a replenishment is needed or not. Partial backordering is applied when a stockout occurs. That is, under the situations of stockouts, customers can choose either to backorder products or to abandon the purchase. Customers are segmented into two classes according to their backordering probabilities. The customer class with high backordering probability is provided with high priority to receive backorders. In this paper we allow more than one outstanding orders to exist, which is not the case in the previous literature. We develop a simulation model for such an inventory system and investigate the impacts of supply disruptions and customer differentiation on this inventory system.

Key establishment for layered group-based Wireless Sensor Networks

Abstract: Establishing pairwise keys for sensors is crucial to secure communications in Wireless Sensor Networks (WSNs). Several key pre-distribution schemes have been proposed to establish pairwise keys, but they are not scalable and suffer from a dramatic degradation of security when the number of compromised sensor exceeds a threshold. In this paper, we propose a Layered Group-based Key Establishment (LGKE) scheme, in which a logic top layer ensures the scalability through an Exclusion Basic System (EBS) technique while a logic low layer adopts a group-based key preload scheme to ensure the security. The security analysis and quantitative evaluation show the superiority of LGKE with regard to scalability, resilience, robustness and communication overhead.

Metamodel analysis on multi-echelon supply chain simulation experiments

Abstract: Metamodels are abstractions of a simulation model to reveal the system's input-output relationship through simple mathematical expression. It provides an analytical way to study the behaviour of complex systems. A multi-echelon supply chain is one of such systems, which is usually extremely difficult, if not impossible, to obtain closed-form analytical solutions due to the intrinsic complexity of the inventory system and its underlying uncertainty. In this paper, we apply the methodology of simulation metamodel to a multi-echelon supply chain problem and conduct statistical analysis of the parameters. The metamodel is validated using training experiment conditions.