Invited Session Tue.2.H 0111

Tuesday, 13:15 - 14:45 h, Room: H 0111

Cluster 13: Logistics, traffic, and transportation [...]

Logistics and network optimization: New problems and new approaches

 

Chair: Frieda Granot and Daniel Granot

 

 

Tuesday, 13:15 - 13:40 h, Room: H 0111, Talk 1

Alexander Richter
An integrated approach to tactical logistics network optimization

Coauthors: Tobias Harks, Felix K├Ânig, Jannik Matuschke, Jens Schulz

 

Abstract:
In global logistics operations, tactic planning aims at laying the groundwork for cost-efficient day-to-day operation by deciding on transport modes, routes, and delivery frequencies between facilities in the network. We consider a fixed charge multi-commodity network flow model to optimize supply chains on the tactical level, that is, the infrastructure is already in place and we seek cost optimal transport and storage modes. Model characteristics include a frequency pattern expansion to capture the tradeoff between inventory costs and economies of scale for transport costs, as well as multidimensional commodity properties and complex tariff structures. We devise local search type and combinatorial heuristics that can be combined with mixed integer programming techniques. To evaluate the quality of these approaches we present a computational study on a set of large-scale real-world instances provided by our industrial cooperation partner. The model and the obtained results are part of the MultiTrans project, a cooperation between the COGA group at TU Berlin and 4flow AG, a market leader in logistics and supply chain management consulting.

 

 

Tuesday, 13:45 - 14:10 h, Room: H 0111, Talk 2

Michal Penn
Cyclic routing of unmanned aerial vehicles

Coauthors: N. Druker, O. Strichman

 

Abstract:
Developing autonomous monitoring systems for Unmanned Aerial Vehicles (UAVs), which facilitate scanning and monitoring a set of targets on the ground is of growing interest in security applications. These monitoring systems have to support complex tasks that include multiple UAVs that should scan and monitor multiple distant predefined targets, with a known distance matrix, in cyclic routes. Each target is associated with a temporal constraint, namely, a relative deadline, that is, the maximum permitted time interval between two successive scanning of the target. Our aim is to determine the minimum number of UAVs required for suitable cyclic route that visits, under the temporal constraints all targets. We formulate the problem as MILP and as Satisfiability Modulo Theories (SMT) problem. We use several solutions methods, such as Mosek, Z3 and DFS and demonstrate their numerical results

 

 

Tuesday, 14:15 - 14:40 h, Room: H 0111, Talk 3

Tal Raviv
Optimal control of battery switching stations

Coauthor: Gil Einy

 

Abstract:
We introduce a new on-line scheduling problem motivated by the business model of Better Place Ltd. The company sells electric vehicles (EV) with replaceable Lithium Ion batteries and provides battery replacement services in Battery Switching Stations (BSS). The BSS Scheduling Problem is defined as follows: a stream of requests for battery switches to be fulfilled is governed by a known, non-homogenous, stochastic process. The disassembled batteries are recharged and used to fulfill future requests. Partly charged batteries can be supplied at a penalty cost that depends on their charging level. The charging duration and power consumption during the process varies depending on the battery and charging technologies. The cost of electricity and the maximum allowed power consumption varies during the planning horizon. The operational goal is to establish a charging policy so as to minimize the expected total electricity and penalty costs. We develop an on-line heuristic for the BSS problem, based on an efficient algorithm for a deterministic version of this problem, and demonstrate its efficiency by an extensive numeric experiment in a realistic setting.

 

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