Computational Optimization, Modelling and Simulation (COMS) Session 2

Time and Date: 15:45 - 17:25 on 11th June 2018

Room: M4

Chair: Tiew On Ting

116 Optimizing Deep Learning by Hyper Heuristic Approach for Classifying Good Quality Images [abstract]
Abstract: Deep Convolutional Neural Network (CNN), which is one of the prominent deep learning methods, has shown a remarkable success in a variety of computer vision tasks, especially image classification. However, tuning CNN hyper-parameters requires expert knowledge and a large amount of manual effort of trial and error. In this work, we present the use of CNN on classifying good quality images versus bad quality images without understanding the image content. The well known data-sets were used for performance evaluation. More importantly we propose a hyper-heuristics approach on CNN for tuning its hyper-parameters. The proposed method encompasses of a high level strategy and various low level heuristics. The high level strategy utilises search performance to determine how to apply low level heuristics to automatically find an optimal set of CNN hyper-parameters. Our experiments show the effectiveness of this hyper-heuristic approach which can achieve high accuracy even when the training size is significantly reduced and conventional CNNs can no longer perform well. In short the proposed hyper-heuristic method does enhance CNN deep learning.
Muneeb Ul Hassan, Nasser R. Sabar and Andy Song
150 An Agent-based Distributed Approach for Bike Sharing Systems [abstract]
Abstract: Shared bikes are wildly welcomed and becoming increasing popular in the world, as a result, quite a few bike sharing systems have been conducted to provide services for the bicycle users. However, the current bike sharing systems are not fexible and humanly enough for the public bicycle users because of the fixed stations and not well considered for the users. In this paper, an agent-based distributed approach for bike sharing systems is proposed, this approach aims at helping users with obtaining a needed shared bike successfully and effciently. We pay more attention on user's preference to improve the satifised degree of the target shared bikes, meanwhile, agent trust and the probabilities are considered to improve the eciency and the success rate. To the end, a practical example simulation and results analysis are given to show its efficiency.
Ningkui Wang, Hayfa Zgaya, Philippe Mathieu and Slim Hammadi
325 A fast vertex-swap operator for the prize-collecting Steiner tree problem [abstract]
Abstract: The prize-collecting Steiner tree problem (PCSTP) is one of the important topics in computational science and operations research. The vertex-swap operation, which involves removal and addition of a pair of vertices based on a given minimum spanning tree (MST), has been proven very effective for some particular PCSTP instances with uniform edge costs. This paper extends the vertex-swap operator to make it applicable for solving more general PCSTP instances with varied edge costs. Furthermore, we adopt multiple dynamic data structures (such as ST trees and logarithmic-time heaps), which guarantee that the total time complexity for evaluating all the O(n2) possible vertex-swap moves is bounded by O(n) · O(m·log n), where n and m denote the number of ver- tices and edges respectively (if we choose to run Kruskal’s algorithm with a Fibonacci heap from scratch after swapping any pair of vertices, the total time complexity would reach O(n2)·O(m+n·logn)). We also prove that after applying the vertex-swap operation, the resulting solutions are necessarily MSTs (unless infeasible).
Yi-Fei Ming, Si-Bo Chen, Yong-Quan Chen and Zhang-Hua Fu
33 Solving CSS-Sprite Packing Problem Using a Transformation to the Probabilistic Non-Oriented Bin Packing Problem [abstract]
Abstract: CSS-Sprite is a technique of regrouping small images of a web page, called tiles, into images called sprites in order to reduce network transfer time. CSS-sprite packing problem is considered as an optimization problem. We approach it as a probabilistic non-oriented two-dimensional bin packing problem (2PBPP|R). Our main contribution is to allow tiles rotation while packing them in sprites. An experimental study evaluated our solution, which outperforms current solutions.
Soumaya Sassi Mahfoudh, Monia Bellalouna and Leila Horchani
71 Optimization of Resources Selection for Jobs Scheduling in Heterogeneous Distributed Computing Environments [abstract]
Abstract: In this work, we introduce slot selection and co-allocation algorithms for parallel jobs in distributed computing with non-dedicated and heterogeneous resources (clusters, CPU nodes equipped with multi-core processors, networks etc.). A single slot is a time span that can be assigned to a task, which is a part of a parallel job. The job launch requires a co-allocation of a specified number of slots starting and finishing synchronously. The challenge is that slots associated with different heterogeneous resources of distributed computing environments may have arbitrary start and finish points, different pricing policies. Some existing algorithms assign a job to the first set of slots matching the resource request without any optimization (the first fit type), while other algorithms are based on an exhaustive search. In this paper, algorithms for effective slot selection are studied and compared with known approaches. The novelty of the proposed approach is in a general algorithm selecting a set of slots efficient according to the specified criterion.
Victor V. Toporkov and Dmitry Yemelyanov