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Presentation on theme: "EFFECT OF VERTICAL TRANSSHIPMENT IN A DELIVERY SYSTEM By Pierre El Khoury."— Presentation transcript:


2 Outline  Some Background  What a Delivery System is?  What an Agents is?  Definition of Transshipment  Framework  Without Transshipment  With Transshipment  Simulations  What did we prove?

3 Where did the idea come from? Delivery Systems Optimization

4 Review Many Researchers focus on identifying a practical field which uses delivery, instead of tackling the delivery problem itself as a concept... Thus, there is no standardized scientific vocabulary to describe variations to the delivery problem

5 Delivery in specific fields Truck Delivery Problem (1) (1) Jun Sawamoto, “Truck Delivery Scheduling System with a Mobile Communication Feature”, International Journal of Information Technology, August 2002.

6 Delivery in specific fields Taxi Delivery Service (2) (3) (2) Shih-Fen Cheng, Xin Qu, “A Service Choice Model for Optimizing Taxi Service Delivery”, School of Information Systems, Singapore Management University. (3) Der-Horng Lee, “A Taxi Dispatch System based on current demands and real-time traffic conditions”, 82nd Annual Meeting of the Transportation Research Board and consideration of publication in Transportation Research Record, November 12, 2002.

7 Delivery in specific fields Shipping Services (4) (5) (4) Ante Munitic, Slavko Simundic, Josko Dvornik, “System Dynamics Modelling of Material Flow of the Port Cargo System”, Split College of Maritime Studies, Faculty of Law Split, Croatia. (5) Mabel Chou, MiaoSong, Chung-Piaw Teo, “Inventory-Routing Problem in Sea Freight: Direct versus Transshipment Model”, July 30, 2003

8 What we did… We did not move much away from what these researchers did… We are thinking about our problem as a food delivery system, where orders are placed online, and many delivery boys handle the delivery on a road mesh. In the system, we have multiple providers (restaurants), and multiple agents (delivery boys)

9 But after we finished our study… We gave our project a more general title, which describes more technically our problem: “Effect of using Transshipment as a vertical area division in a Delivery System”

10 What is a Delivery System A delivery system is widely referred to as a “Pickup and Delivery problem”, according to the literature review we conducted… (6)(7)(8)(…) (6) Snezana Mitrovic-Minic, Gilbert Laporte, “The Pickup and Delivery Problem with Time Windows and Transshipment”, INFOR Vol. 44, p. 217-227, Aug 2006. (7) Sophie N. Parragh Karl F. Doerner Richard F., “A survey on pickup and delivery problems”, Hartl Institut fur Betriebswirtschaftslehre, Universitat Wien Brunnerstr, Austria, April 16, 2008. (8) Quan Lu, Maged Dessouky, “An Exact Algorithm for the Multiple Vehicle Pickup and Delivery Problem”, University of Southern California, Department of Industrial and Systems Engineering, December 12, 2002.

11 Pickup location

12 Delivery Location

13 Delivery Networks

14 What are agents? The means by which we process the delivery. In our example, agents are Delivery Boys

15 Transshipment Transshipment is the shipping of goods to intermediate locations before they are delivered to their final destination

16 Transshipment From a legal point of view, Transshipment is looked upon with caution, since it could be used for illegal activities (ranging from smuggling to terrorism) By transshipment, some people try to disguise the point of origin of their goods from Customs officials (9) (9) US Customs and Borders Protection, “TRANSSHIPMENT, TECHNICAL INFORMATION FOR PRE-ASSESSMENT SURVEY”, Focused Assessment Program Exhibit 5L, US Department of Homeland Security, October 2003.

17 Transshipment Transshipment is widely used in delivery systems optimization (6)(12). It is also widely used to optimize supply chain management (10)(11)(12) (6) Snezana Mitrovic-Minic, Gilbert Laporte, “The Pickup and Delivery Problem with Time Windows and Transshipment”, INFOR Vol. 44, p. 217-227, Aug 2006. (10) Yale T. Herer, Michal Tzur, “The Dynamic Transshipment Problem”, Naval Research Logistics, Vol. 48, (2001) (11) Jing Shao, Harish Krishnan, S. Thomas McCormick, “Incentives for Transshipment in a Supply Chain with Decentralized Retailers”, September 25, 2009. (12) Rodolfo Dondo, Carlos A. Méndez, Jaime Cerdá, “The supply-chain pick-up and delivery problem with transshipments ”, INTEC (UNL-CONICET), Güemes 3450, 2500- Santa Fe, Argentina, 24 June 2009.

18 Transshipment here In this project, we study the effect of transshipment at specific locations inside the network and we compare to the performance of the delivery system without transshipment.

19 Framework  Assumptions:  Cost of preparing the goods at the provider node is small compared to the time needed by any agent to reach this node.  Environment costs (road costs, or costs between nodes) do not change with time.  Two cases: Delivery system without transshipment and with Transshipment

20 Delivery with No Transshipment

21 What is A*?

22 Why A*, not Dijkstra?  A* is almost Dijkstra, with a heuristic  But in Dijkstra, each node has to be aware of the entire search space in order for the algorithm to operate. Therefore, every node has to know the exact costs between nodes in the network  A* is admissible and optimal (13)  Also, the time complexity of A* is better than Dijkstra since we are using a heuristic (14) (13) Dechter, Rina, Judea Pearl, "Generalized best-first search strategies and the optimality of A*“, Journal of the ACM 32 (3): 505–536, (1985). (14) Russell S J, Norvig, P, “Artificial Intelligence: A Modern Approach”, Upper Saddle River, Prentice Hall, pp. 97–104, (2003).

23 Delivery with Transshipment

24 Simulations Table1: 7*7 No Transshipment Simulation on a 7*7 network12345678910Total2663 Total Time281263256267268254283246291254Average266.3 Table2: 3*3 No Transshipment Simulation on a 3*3 network12345678910Total1037 Total Time10412597105111122861029293Average103.7 Table 3: 7*7 Vertical Transshipment Simulation on a 7*7 network12345678910Total3124 Total Time345308312283305307303311331319Average312.4 Table 4: 3*3 Vertical Transshipment Simulation on a 3*3 network12345678910Total1236 Total Time133107119153103113150122116120Average123.6

25 What did we prove? These simulations show that using two agents to process deliveries between two areas, using vertical transshipment, is worse than using them without transshipment. Therefore, splitting the environment into two distinct areas was not beneficial for the system.

26 How can we improve?  Check for the effect of transshipment in larger networks  Check for the effect of transshipment with more agents  Modify the transshipment concept adopted, so that transshipment can occur all over the network under specific conditions

27 The End…


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