Cost-based filtering for stochastic inventory control

Abstract. An interesting class of production/inventory control problems considers a single product and a single stocking location, given a stochastic demand with a known non-stationary probability distribution. Under a widely-used control policy for this type of inventory system, the objective is to find the optimal number of replenishments, their timings and their respective order-up-to-levels that meet customer demands to a required service level. We extend a known CP approach for this problem using a cost-based filtering method. Our algorithm can solve to optimality instances of realistic size much more efficiently than previous approaches, often with no search effort at all.

Business models and network design in hinterland transport

International Series in Operations Research & Management ScienceInternational container transport is the backbone of global supply chains. Hinterland transport, the transport from the port to the final destination and vice versa, is an important component of international container transport. However, academic attention to hinterland transport has emerged only recently. This chapter discusses business models and network design in hinterland transport. Understanding business models is relevant, as many different types of companies (e.g., shipping lines, terminal operating companies and forwarders) play a role in hinterland transport. Their business models influence how they position themselves in the market, their stance concerning cooperation and coordination in hinterland transport, and their scope in network design. Network design is a core issue in hinterland transport. New services need to be designed—and in such a way that they are expected to be profitable. Furthermore, current service patterns only change through deliberate redesign. So competition through the (re)design of transport services is a very important—perhaps the most important—form of competition in intermodal freight transport. One potentially promising innovation in this respect is the extended gate concept, where an inland hub becomes the ‘virtual gate’ of the deep sea terminal

Transit Network Re-Timetabling and Vehicle Scheduling

Abstract. In the transit planning literature, network timetabling and vehicle scheduling are usually treated in a sequential manner. In this paper, we focus on combining important features of these two steps, and underline how their simultaneous optimization is meaningful and can bring important improvements to both quality of service and level of resources required. We deal with the objectives of networkwide quality of service through number and quality of the transfers and evenness of the line headways, and with the resources side through number of vehicles needed. Our approach is adapted to the problem faced by regulating authorities, treating among others intermodality, multi-periods for headways and travel times, and complex timetable schemes. We introduce an optimization procedure based on Iterated Local Search and present computational experiments carried out on a real large transit network, showing substantial improvements in both quality of service and level of resources compared to the current practice

What Makes Logistics Integration More Effective? Governance from Contractual and Relational Perspectives

Third-party logistics (3PL) user-provider integration is attracting increasing attention from both academics and practitioners. However, it remains unclear how best to adopt governance mechanisms to safeguard 3PL user-provider integration (e.g., information sharing and process coordination). Based on transaction cost economics and social exchange theory, this study examined the individual and joint effects of contractual (e.g., detailed contracts and contract application) and relational governance (e.g., trust and relational norms) on 3PL user-provider integration for operational performance. We conducted a survey involving 247 3PL service users and analyzed the conceptual model using the method of structural equation modeling. The results showed that process coordination improved operational performance, while information sharing alone did not significantly improve operational performance but complemented the role of process coordination in improving operational performance. In addition, having detailed contracts was positively related to process coordination, while contract application was positively related to information sharing. Trust was not significantly related to information sharing or process coordination, while relational norms were positively related to both. Finally, three joint effects on 3PL user-provider integration were found. Two of them were substitutional (detailed contracts and relational norms; contract application and trust), and one was complementary (detailed contracts and trust). This study makes several theoretical contributions and provides novel guidelines for 3PL relationship development