6th Workshop on Computational Optimization, Modelling & Simulation (COMS) Session 3
Time and Date: 16:40 - 18:20 on 1st June 2015
Room: V201
Chair: Leifur Leifsson
256 | Multi-Objective Design Optimization of Planar Yagi-Uda Antenna Using Physics-Based Surrogates and Rotational Design Space Reduction [abstract] Abstract: A procedure for low-cost multi-objective design optimization of antenna structures is discussed. The major stages of the optimization process include: (i) an initial reduction of the search space aimed at identifying its relevant subset containing the Pareto-optimal design space, (ii) construction—using sampled coarse-discretization electromagnetic (EM) simulation data—of the response surface approximation surrogate, (iii) surrogate optimization using a multi-objective evolutionary algorithm, and (iv) the Pareto front refinement. Our optimization procedure is demonstrated through the design of a planar quasi Yagi-Uda antenna. The final set of designs representing the best available trade-offs between conflicting objectives is obtained at a computational cost corresponding to about 172 evaluations of the high-fidelity EM antenna model. |
Slawomir Koziel, Adrian Bekasiewicz, Leifur Leifsson |
644 | Agent-Based Simulation for Creating Robust Plans and Schedules [abstract] Abstract: The paper describes methods for constructing the robust schedules using agent-based simulation. The measure of robustness represents the resistance of the schedule to random phenomena and we present the method for calculating robustness of the schedule. The procedure for creating the robust schedule combines standard solutions for planning and scheduling with computer simulation. It is described in detail and allows creation an executable robust schedule. Three different procedures for increasing the robustness (by changing the order of allocation of resources, by changing a plan and increasing time reserves) are short explained. The presented techniques were tested using real detailed simulation model of an existing container terminal. |
Peter Jankovič |
413 | Shape Optimization of Trawl-Doors Using Variable-Fidelity Models and Space Mapping [abstract] Abstract: Trawl-doors have a large influence on the fuel consumption of fishing vessels. Design and optimization of trawl-doors using computational models are key factors in minimizing the fuel consumption. This paper presents an efficient optimization algorithm for the design of trawl-door shapes using computational fluid dynamic models. The approach is iterative and uses variable-fidelity models and space mapping. The algorithm is applied to the design of a multi-element trawl-door, involving four design variables controlling the angle of attack and the slat position and orientation. The results demonstrate that a satisfactory design can be obtained at a cost of a few iterations of the algorithm. Compared with direct optimization of the high-fidelity model and local response surface surrogate models, the proposed approach requires 79% less computational time while, at the same time, improving the design significantly (over 12% increase in the lift-to-drag ratio). |
Ingi Jonsson, Leifur Leifsson, Slawomir Koziel, Yonatan Tesfahunegn, Adrian Bekasiewicz |
347 | Optimised robust treatment plans for prostate cancer focal brachytherapy [abstract] Abstract: Focal brachytherapy is a clinical procedure that can be used to treat low-risk prostate cancer with reduced side-effects compared to conventional brachytherapy. Current practice is to manually plan the placement of radioactive seeds inside the prostate to achieve a desired treatment dose. Problems with the current practice are that the manual planning is time-consuming and high doses to the urethra and rectum cause undesirable side-effects. To address this problem, we have designed an optimisation algorithm that constructs treatment plans which achieve the desired dose while minimizing dose to organs at risk. We also show that these seed plans are robust to post-operative movement of the seeds within the prostate. |
John Betts, Chris Mears, Hayley Reynolds, Guido Tack, Kevin Leo, Martin Ebert, Annette Haworth |
514 | Identification of Multi-inclusion Statistically Similar Representative Volume Element for Advanced High Strength Steels by Using Data Farming Approach [abstract] Abstract: Statistically Similar Representative Volume Element (SSRVE) is used to simplify computational domain for microstructure representation of material in multiscale modelling. The procedure of SSRVE creation is based on optimization loop which allows to find the highest similarity between SSRVE and an original material microstructure. The objective function in this optimization is built upon computationally intensive numerical methods, including simulations of virtual material deformation, which is very time consuming. To avoid such long lasting calculations we propose to use the data farming approach to identification of SSRVE for Advanced High Strength Steels (AHSS) characterized by multiphase microstructure. The optimization method is based on a nature inspired approach which facilitates distribution and parallelization. The concept of SSRVE creation as well as the software architecture of the proposed solution is described in the paper in details. It is followed by examples of the results obtained for the identification of SSRVE parameters for DP steels which are widely exploited in modern automotive industry. Possible directions for further development and uses are described in the conclusions. |
Lukasz Rauch, Danuta Szeliga, Daniel Bachniak, Krzysztof Bzowski, Renata Słota, Maciej Pietrzyk, Jacek Kitowski |