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 Schedule
			| Thursday, 30 January
 |  | 08:30-09:10 | Welcome-registration-coffee | B14-B15-B16 |  | 09:10-09:30 | Opening session | Amphi Cuccaroni |  | 09:30-10:30 | Plenary session  - Adam Letchford (Chair: Martine Labbé) | Amphi Cuccaroni |  | 10:30-11:20 | Coffee break | B14-B15-B16 |  | 11:20-12:40 | Parallel sessions |  |  | Multi-objective Optimization Chair: Sara Tari
 Room: E501
 | Health-care Chair: Véronique François
 Room: E502
 | Public Transportation Chair: Javier Duran Micco
 Room: E503
 | Global Optimization Chair: Olivier Rigal
 Room: E601
 | Analytics 1 Chair: Rafael Van Belle
 Room: E602
 |  | 12:40-14:10 | Lunch/ORBEL Board meeting | B14-B15-B16/E501 |  | 14:10-15:10 | Parallel sessions |  |  | Air, Rail and Multimodal Transportation Chair: Paola Paregrini
 Room: E501
 | Game Theory Chair: Lotte Verdnock
 Room: E502
 | Transportation of People Chair: Yves Molenbruch
 Room: E503
 | Multi-level Optimization Chair: Concepcion Dominguez
 Room: E601
 | Analytics 2 Chair: Vedavyas Etikala
 Room: E602
 |  | 15:10-15:50 | Coffee break | B14-B15-B16 |  | 15:50-16:40 | Parallel sessions |  |  | Sport Timetabling Chair: Dries Goossens
 Room: E501
 | Project Management and Scheduling Chair: Fan Yang
 Room: E502
 | Rich Routing and Graphs Chair: Alexandre Bontems
 Room: E503
 | Logistics Chair: Yuan Yuan
 Room: E601
 | Analytics 3 Chair: Jari Peeperkorn
 Room: E602
 |  | 16:50-17:30 | ORBEL general assembly | Amphi Cuccaroni |  | 19:00-20:00 | Cocktail | Bar Zango |  | 20:30-23:00 | Dinner | La Terrasse des Ramparts |  | Friday, 31 January
 |  | 09:30-10:30 | Plenary session - Miguel F. Anjos (Chair: Luce Brotcorne) | Amphi Cuccaroni |  | 10:30-11:20 | Coffee break | B14-B15-B16 |  | 11:20-12:40 | Parallel sessions |  |  | Automatic Configuration and Metaheuristics Analysis Chair: Kenneth Sorensen
 Room: E501
 | Real Life and Integrated Problems Chair: Jeroen Belien
 Room: E502
 | Warehouse Management Chair: Harol Mauricio Gamez
 Room: E601
 | Analytics 4 Chair: Noureddine Kouaissah
 Room: E602
 |  | 12:40-14:10 | Lunch | B14-B15-B16 |  | 14:10-15:10 | Parallel sessions |  |  | Orbel Award Chair: Jeroen Belien
 Room: E501
 | Optimization Chair: Julien Dewez
 Room: E502
 | Trucking Optimization Chair: Hatice Çalik
 Room: E601
 | Analytics 5 Chair: Diego Olaya
 Room: E602
 |  | 15:10-15:50 | Coffee break | B14-B15-B16 |  | 15:50-16:50 | Parallel sessions |  |  | Learning and Optimization Chair: Johan Van Kerckhoven
 Room: E501
 | Lot-sizing and Inventory Chair: Philippe Chevalier
 Room: E502
 | Rich Routing Chair: Cristian Aguayo
 Room: E601
 |  | 17:00-17:15 | ORBEL award and closing session | Amphi Cuccaroni |  | 17:15-18:30 | Closing cocktail | B14-B15-B16 |  | 
 |  Thursday 11:20 - 12:40 Multi-objective Optimization
 Room E501 - Chair: Sara Tari
 
 Thursday 11:20 - 12:40 Health-care
 Room E502 - Chair: Véronique François
 
 Thursday 11:20 - 12:40 Public Transportation
 Room E503 - Chair: Javier Duran Micco
 
 Thursday 11:20 - 12:40 Global Optimization
 Room E601 - Chair: Olivier Rigal
 
 Thursday 11:20 - 12:40 Analytics 1
 Room E602 - Chair: Rafael Van Belle
 
 Thursday 14:10 - 15:10 Air, Rail and Multimodal Transportation
 Room E501 - Chair: Paola Pellegrini
 
 Thursday 14:10 - 15:10 Game Theory
 Room E502 - Chair: Lotte Verdnock
 
 Thursday 14:10 - 15:10 Transportation of People
 Room E503 - Chair: Yves Molenbruch
 
 Thursday 14:10 - 15:10 Multi-level Optimization
 Room E601 - Chair: Concepcion Dominguez
 
 Thursday 14:10 - 15:10 Analytics 2
 Room E602 - Chair: Vedavyas Etikala
 
 Thursday 15:50 - 16:50 Sport Timetabling
 Room E501 - Chair: Dries Goossens
 
 Thursday 15:50 - 16:50 Project Management and Scheduling
 Room E502 - Chair: Fan Yang
 
 Thursday 15:50 - 16:50 Rich Routing and Graphs
 Room E503 - Chair: Alexandre Bontems
 
 Thursday 15:50 - 16:50 Logistics
 Room E601 - Chair: Silia Mertens
 
 Thursday 15:50 - 16:50 Analytics 3
 Room E602 - Chair: Jari Peeperkorn
 
 Friday 11:20 - 12:40 Automatic Configuration and Metaheuristics Analysis
 Room E501 - Chair: Kenneth Sorensen
 
 Friday 11:20 - 12:40 Real Life and Integrated Problems
 Room E502 - Chair: Jeroen Belien
 
 Friday 11:20 - 12:40 Warehouse Management
 Room E601 - Chair: Harol Mauricio Gamez
 
 An Exact Model for the order picking problem Farzaneh Rajabighamchi (Maastricht)
 Co-authors: Christof Defryn, Stan Van Hoesel
 Abstract:
 order picking activity has become increasingly significant to manage due to the introduction of operating programs such as Just-In-Time (JIT) principle, cycle time reduction and quick response to orders and new marketing strategies such as micro marketing. With so many new technological advancements, the world of e-Commerce is transforming rapidly. This significant growth in digital marketing and daily increase in the number of customers who do online shopping, impose challenges and  pressure for warehouses to operate more efficient and fast to satisfy customer demands. Any under-performance in order picking can result in high operational cost and unsatisfactory service for the warehouse and the whole supply chain. As a consequence, to increase the operate efficiency, the order-picking process needs to be optimally controlled.
The order picking process, defined as the retrieval of products from their storage locations based on customer orders, is the most time-consuming warehouse process, especially in the case of manual order picking. Therefore, it contributes largely to the operational cost of the warehouse (Tompkins et al. 1996). By reducing the picking time which consists of travel time  and  time  for picking the products, order picking productivity can be improved. one of the best ways of reducing travel times is by finding a sequence in which items have to be picked from storage such that travel distances are as short as possible.
This paper is dealing with the sequencing and routing of order pickers within a multi-block warehouse layout with parallel aisles. In the literature, exact algorithms only exist for small warehouses with few number of cross aisles, while for other larger warehouse types some heuristics methods are provided. Most of the existing models rely on the definition of a (Steiner) Travelling Salesman problem over the set of product locations. 
This paper will focus on presenting an exact routing method for warehouses with  parallel  aisles, a depot, and possibilities for changing aisles by using cross aisles. These cross aisles are usually located at the front and back of the warehouse, but there can also be one or more cross aisles between them. to the best of our knowledge, this problem can not be solved in a polynomial-time except when there are a bounded number of cross-aisles. we propose an exact algorithm for any number of cross-aisles to use it for problem implementation. We show in this paper that the problem can be efficiently solved optimally with integer programming using an exact formulation as well as adequate pre-processing.
We present a new efficient exact mixed integer linear programming formulation that considers the picker routing based on the active aisle corner nodes. in order to increase the calculation speed and reduce the running time, first we propose some pre-processig algorithms which are based on network(graph) reduction methods. then, an exact mixed integer model is implemented and evaluated experimentally. the presented method allows solving bigger (more realistic) instances in a minimum amount of time. 
Moreover, some problem instances from the literature are implemented and detailed numerical experiments are carried out to evaluate the performances of the proposed model and compare the results with the existing methods in literature. In conclusion, for the majority of the instances, a newly developed model appears to perform better than the existing models and it comes out to be an efficient methods in terms of solution quality and computational efficiency.  The results illustrate that the proposed model outperforms existing formulations in simillar articles in terms of simplicity, size and calculation time.
 
Integrating Classification, Labelling and Packaging Regulations in Manual Order Picking Sarah Vanheusden (Hasselt University, research group logistics)
 Co-authors: Teun van Gils, Katrien Ramaekers and An Caris
 
Integration of multiple order picking planning problems and vehicle routing: state of the art Ruben D'haen (UHasselt)
 Co-authors: Kris Braekers, Katrien Ramaekers
 
The Scattered Storage Assignment Problem Harol Mauricio Gamez Alban (University of Antwerpen)
 Co-authors: Trijntje Cornelissens and Kenneth Sörensen
 
 Friday 11:20 - 12:40 Analytics 4
 Room E602 - Chair: Noureddine Kouaissah
 
 Friday 14:10 - 15:10 Orbel Award
 Room E501 - Chair: Jeroen Belien
 
 Friday 14:10 - 15:10 Optimization
 Room E502 - Chair: Julien Dewez
 
 Friday 14:10 - 15:10 Trucking Optimization
 Room E601 - Chair: Hatiz Çalik
 
 Friday 14:10 - 15:10 Analytics 5
 Room E602 - Chair: Diego Olaya
 
 Friday 15:50 - 16:50 Learning and Optimization
 Room E501 - Chair: Jorik Jooken
 
 Friday 15:50 - 16:50 Lot-sizing and Inventory
 Room E502 - Chair: Philippe Chevalier
 
 Friday 15:50 - 16:50 Rich Routing
 Room E601 - Chair: Cristian Aguayo
 
 
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	  	|  | ORBEL  - Conference chairs: Diego Cattaruzza and Maxime Ogier 
 
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