Invited Session Tue.2.H 1029

Tuesday, 13:15 - 14:45 h, Room: H 1029

Cluster 15: Multi-objective optimization [...]

Interactive multiobjective optimization


Chair: Kaisa Miettinen



Tuesday, 13:15 - 13:40 h, Room: H 1029, Talk 1

Martin Josef Geiger
Multi-objective inventory routing: Reference-point-based search, representations, and neighborhoods

Coauthors: Thibaut Barthélemy, Marc Sevaux


The talk considers a multi-objective generalization of the inventory routing problem, a problem arising in transportation/the physical distribution of goods. In our problem formulation, inventory levels and routing costs are not combined into an overall evaluation function but treated separately. The problem is solved by the use of metaheuristics, and numerical results are computed and reported.\Particular emphasis has been laid on the representation of solutions from a practical point of view. In detail, individual frequency values are derived for each customer, implementing a recurring delivery policy. On the one hand, this leads to a relatively easy, understandable encoding of delivery policies. On the other hand however, the possibilities of the optimization approach are depending on the chosen representation, and interrelations with the chosen neighborhoods and search-/optimization-strategies become apparent.\Our findings show that there is great potential for tradeoffs between the two objectives. Especially in tactical planning situations, this problem extension can provide useful insights. A DSS making use of multiple reference points has thus been realized.



Tuesday, 13:45 - 14:10 h, Room: H 1029, Talk 2

Kaisa Miettinen
Interactive Pareto Navigator method for nonconvex multiobjective optimization

Coauthors: Markus Hartikainen, Kathrin Klamroth


We describe a new interactive method called Nonconvex Pareto Navigator which extends the convex Pareto Navigator method for nonconvex multiobjective optimization problems. In the new method, a piecewise linear approximation of the Pareto optimal set is first generated using a relatively small set of Pareto optimal solutions. The decision maker (DM) can then navigate on the approximation and direct the search for interesting regions in the objective space. In this way, the DM can conveniently learn about the interdependencies between the conflicting objectives and possibly adjust one’s preferences. Besides nonconvexity, the new method contains more versatile options for directing the navigation. The Nonconvex Pareto Navigator method aims at supporting the learning phase of decision making. It is well-suited for computationally expensive problems because the navigation is computationally inexpensive to perform on the approximation. Once an interesting region has been found, the approximation can be refined in that region or the DM can ask for the closest actual Pareto optimal solution.



Tuesday, 14:15 - 14:40 h, Room: H 1029, Talk 3

Hans L. Trinkaus
Multi criteria decision support in real-time


Integration of Project, Process and Knowledge Management.
The business processes observed here affect various organizational units during evolving in successive phases. A few examples to that: surveillance and maintenance of ship equipment, transport logistics of wind wheel parts, and innovation of OLED technology.
At certain stations of those processes several things have to be done: knowledge retrieval and storage, working out of prescribed context relevant documents or performing situation dependent programs, and exploring and evaluating various feasible scenarios. Again some examples: time- or cost-optimal remedying of a ship's defect, selecting, assimilating and tracking of conveyor chains, and designing and simulating product or shop floor prototypes.
In finding "best paths'' through such dynamic processes two tools, addressing the outstanding visual cognition of man, assist: "processBoard'', for designing, adapting, monitoring and controlling processes on a virtual board, and "knowCube'', for getting balanced decisions by using graphical means, applicable by non-experts, too. Both tools are combined in a web portal.


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