Technical Sessions – Monday July 11

4 - Adaptive Large Neighborhood Search for Service Technician
Routing and Scheduling Problems
Richard Hartl, Dept of Management, University of Vienna,
Bruenner Str. 72, A-1210, Vienna, Austria,
richard.hartl@univie.ac.at, Attila Kovacs, Sophie Parragh, Karl
Doerner
We define the service technician routing and scheduling problem with and without
team building. Technicians must complete a set of service tasks with time
windows. Each technician has different skills at different levels and each task
demands technicians with the required skills. Sometimes technicians have to
be grouped into teams for completing complex tasks. The objective is to minimize
total routing and outsourcing costs. Using an adaptive large neighborhood
search algorithm, high quality solutions are obtained within short computation
times for both, artificial and real world instances.
� MB-10
Monday, 14:00-15:30
Meeting Room 111
Strategic Network Design for Time-sensitive
Networks
Stream: Time-Definite Logistics
Invited session
Chair: Anne Lange, Operations Planning Acc. & Control, Technische
Universiteit Eindhoven, Faculteit Industrial Engineering &
Innovation Sciences, Postbus 513, 5600 MB, Eindhoven,
Netherlands, a.lange@tue.nl
1 - A New Method for a Cost-oriented Robust Supply Chain
Design
Thomas Makuschewitz, BIBA - Bremer Institut für Produktion
und Logistik GmbH at the University of Bremen, Hochschulring
20, 28359, Bremen, Germany, mak@biba.uni-bremen.de, Bernd
Scholz-Reiter
A robust supply chain design is given by the capability of the network to cope
with expected and unexpected changes of key parameters. In this talk we measure
the robustness with the stability radius that reflects the smallest perturbation
of parameters that destabilizes the network. Based on a fluid approximation
of a multiclass queueing network and findings concerning the stability
radius we present a method for a robust network design. This method allows
finding the number of production locations, the allocation of production steps
and capacities that maximizes robustness for given costs.
2 - Integrated Bio-refinery and Forest Products Supply
Chain Network Design
Sophie Damours, Mechanical Engineering Dept, Université
Laval, 1065 Avenue de la Medecine, Pavillon Pouliot, G1V 0A6,
Quebec, Canada, Sophie.damours@forac.ulaval.ca, Yan Feng,
Luc LeBel, Mustapha Nourelfath
We present a mixed integer programming model to support the design of the integrated
bio-refinery and forest product supply chain. A general market-driven
supply chain network structure is proposed allowing the optimal investment decisions
to be made in choosing the right facilities, technologies, capacities, and
their locations, that strategically maximize the supply chain value. In the model
development, the biomass and energy supply decisions are also considered as
decision variables. The model is validated using an experimental case. It is
used to analyse the need for timely policy making.
3 - Integrated Scheduling of Production and Distribution
Operations for Rapidly Perishable Products
Tsung-Sheng Chang, Graduate Institute of Logistics
Management, National Dong Hwa University, 1, Sec.2,
Da-Hsueh Rd., Shou-Feng, 974, Hualien, Taiwan,
ts@mail.ndhu.edu.tw, Ya-Ching Lin
The major challenge faced by perishable-product logistics managers is how to
control the quality of perishable products since they continuously and often
rapidly decay throughout the supply chain. This research thus seeks to deal
with the time-sensitive issue of managing perishable-product logistics by effectively
integrating the scheduling of production and distribution operations.
The integrated problem is NP-hard, and involves combining various logistics
activities. Therefore, this research develops decomposition-based approaches
to solve the problem.
IFORS 2011 - Melbourne MB-11
4 - Frequency Driven Strategic Design for Less-thantruckload
Networks
Anne Lange, Operations Planning Acc. & Control, Technische
Universiteit Eindhoven, Faculteit Industrial Engineering &
Innovation Sciences, Postbus 513, 5600 MB, Eindhoven,
Netherlands, a.lange@tue.nl
Less-than-truckload transportation benefits from frequent terminal departures.
Network optimization models integrating frequencies exist, but strongly rely
on data and assumptions that are error-prone for strategic planning. This paper
suggests as an alternative approach a heuristic algorithm generating networks
while ensuring frequencies. Simulating transportation on the networks allows
gaining high-level insights on their behavior. Results show that the mere existence
of minimal frequencies rather than the exact frequency-setting is of
relevance for various aspects of network performance.
� MB-11
Monday, 14:00-15:30
Meeting Room 112
Queueing Models and Analyses I
Stream: Submodular Structures and Optimization
Invited session
Chair: Yutaka Takahashi, Graduate School of Informatics, Kyoto
University, Sakyo-ku, 606-8501, Kyoto, Japan,
takahashi@i.kyoto-u.ac.jp
1 - Conditional Sojourn Times of Processor-Sharing
Queues
Chia-Li Wang, Applied Mathematics Dept, National Dong Hwa
University, Shoufeng, 974, Hualien, Taiwan,
cwang@mail.ndhu.edu.tw
Queues operated by a processor-sharing mode have important applications in
many modern systems. However, performance measures of the sojourn time are
difficult to derive, even with given initial condition. In addition, when the system
limit is finite, the sojourn time is more complicated. In this paper, we take
an algebraic approach to derive the moments of the sojourn time. We obtain an
iterative formula and use it to investigate properties of the conditional sojourn
time. The approach is simple and intuitive, and can be applied to queues with
multiple-class customers as well.
2 - An Efficient Numerical Method for Multi-server Retrial
Queues with Abandonments
Tuan Phung-Duc, Dept. of Systems Science, Graduate School of
Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku,
Kyoto City, 606-8501, Kyoto, Japan, tuan@sys.i.kyoto-u.ac.jp,
Yutaka Takahashi
We consider an M/M/c/c retrial queue where those customers that find all the
servers being fully occupied either leave the queue forever or join an orbit to
retry later. After some exponentially distributed time in the orbit, a retrial customer
either retries to occupy an idle server or abandons receiving service. Using
a matrix continued fraction approach, we develop an efficient algorithm to
compute the joint stationary distribution of the number of busy servers and the
number of customers in the orbit. Numerical examples are presented to show
the influence of retrials and abandonments.
3 - A Simple Backlog Evaluation Formula based on the
Stochastic Network Calculus with Many Flows
Kazutomo Kobayashi, Faculty of Engineering, Nagasaki
University, 1-14, Bunkyo-machi, 852-8521, Nagasaki, Japan,
kobayashi@cis.nagasaki-u.ac.jp, Yukio Takahashi, Yukihiro
Takada
In a previous paper, the authors proposed a new stochastic network calculus for
many flows from an approach like large deviations techniques, and obtained
asymptotic end-to-end evaluation formulas for output burstiness and backlog.
In this paper, we apply this stochastic network calculus to a heterogeneous tandem
network with many forwarding flows and cross traffic flows, and obtain a
simple evaluation formula for the end-to-end backlog.
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