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See detailBayesian optimization to enhance coverage performance of a swarm of UAV with chaotic dynamics
Kieffer, Emmanuel UL; Rosalie, Martin UL; Danoy, Grégoire UL et al

Scientific Conference (2018, February 26)

We introduce the optimization of CACOC through Bayesian Optimization. CACOC is based on a chaotic system, i.e. Rossler system whose behavior can be modified by tuning the α parameter. In order to evaluate ... [more ▼]

We introduce the optimization of CACOC through Bayesian Optimization. CACOC is based on a chaotic system, i.e. Rossler system whose behavior can be modified by tuning the α parameter. In order to evaluate the performance of CACOC for different value of α, the coverage metric has to be evaluated after simulation. The latter is time-consuming. Therefore, a surrogate-based optimization, i.e. Bayesian Optimization has been privilegied to tackle this issue. An analysis of the chaotic system with the obtained α value has been performed to compare the periodic orbits and their associated patterns. Numerical results show that the best α value avoid a waste of time in periodic region of the bifurcation diagram. Future works will focus on more complex chaotic system as well as new application domain of the optimized CACOC approach. [less ▲]

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See detailClustering approaches for visual knowledge exploration in molecular interaction networks.
Ostaszewski, Marek UL; Kieffer, Emmanuel UL; Danoy, Gregoire et al

in BMC bioinformatics (2018), 19(1), 308

BACKGROUND: Biomedical knowledge grows in complexity, and becomes encoded in network-based repositories, which include focused, expert-drawn diagrams, networks of evidence-based associations and ... [more ▼]

BACKGROUND: Biomedical knowledge grows in complexity, and becomes encoded in network-based repositories, which include focused, expert-drawn diagrams, networks of evidence-based associations and established ontologies. Combining these structured information sources is an important computational challenge, as large graphs are difficult to analyze visually. RESULTS: We investigate knowledge discovery in manually curated and annotated molecular interaction diagrams. To evaluate similarity of content we use: i) Euclidean distance in expert-drawn diagrams, ii) shortest path distance using the underlying network and iii) ontology-based distance. We employ clustering with these metrics used separately and in pairwise combinations. We propose a novel bi-level optimization approach together with an evolutionary algorithm for informative combination of distance metrics. We compare the enrichment of the obtained clusters between the solutions and with expert knowledge. We calculate the number of Gene and Disease Ontology terms discovered by different solutions as a measure of cluster quality. Our results show that combining distance metrics can improve clustering accuracy, based on the comparison with expert-provided clusters. Also, the performance of specific combinations of distance functions depends on the clustering depth (number of clusters). By employing bi-level optimization approach we evaluated relative importance of distance functions and we found that indeed the order by which they are combined affects clustering performance. Next, with the enrichment analysis of clustering results we found that both hierarchical and bi-level clustering schemes discovered more Gene and Disease Ontology terms than expert-provided clusters for the same knowledge repository. Moreover, bi-level clustering found more enriched terms than the best hierarchical clustering solution for three distinct distance metric combinations in three different instances of disease maps. CONCLUSIONS: In this work we examined the impact of different distance functions on clustering of a visual biomedical knowledge repository. We found that combining distance functions may be beneficial for clustering, and improve exploration of such repositories. We proposed bi-level optimization to evaluate the importance of order by which the distance functions are combined. Both combination and order of these functions affected clustering quality and knowledge recognition in the considered benchmarks. We propose that multiple dimensions can be utilized simultaneously for visual knowledge exploration. [less ▲]

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See detailA new modeling approach for the biobjective exact optimization of satellite payload configuration
Kieffer, Emmanuel UL; Danoy, Grégoire UL; Bouvry, Pascal UL et al

in International Transactions in Operational Research (2017)

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See detailBayesian Optimization Approach of General Bi-level Problems
Kieffer, Emmanuel UL; Danoy, Grégoire UL; Bouvry, Pascal UL et al

in Proceedings of the Genetic and Evolutionary Computation Conference Companion (2017)

Detailed reference viewed: 63 (3 UL)
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See detailCo-evolutionary approach based on constraint decomposition
Kieffer, Emmanuel UL; Danoy, Grégoire UL; Bouvry, Pascal UL et al

in Co-evolutionary approach based on constraint decomposition (2016, October)

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See detailOn Bi-level approach for Scheduling problems
Kieffer, Emmanuel UL; Danoy, Grégoire UL; Bouvry, Pascal UL

Scientific Conference (2016, April)

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See detailHybrid mobility model with pheromones for UAV detection task
Kieffer, Emmanuel UL; Danoy, Grégoire UL; Bouvry, Pascal UL et al

in Hybrid mobility model with pheromones for UAV detection task (2016)

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See detailA Novel Co-evolutionary Approach for Constrained Genetic Algorithms
Kieffer, Emmanuel UL; Guzek, Mateusz UL; Danoy, Grégoire UL et al

in Proceedings of the 2016 on Genetic and Evolutionary Computation Conference Companion (2016)

Detailed reference viewed: 94 (12 UL)
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See detailBi-objective Exact Optimization of Satellite Payload Power Configuration
Kieffer, Emmanuel UL; Stathakis, Apostolos UL; Danoy, Grégoire UL et al

in VIII ALIO/EURO Workshop on Applied Combinatorial Optimization (2014, December)

Detailed reference viewed: 88 (22 UL)
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See detailMulti-Objective Evolutionary Approach for the Satellite Payload Power Optimization Problem
Kieffer, Emmanuel UL; Stathakis, Apostolos UL; Danoy, Grégoire UL et al

in IEEE Symposium Series on Computational Intelligence (IEEE SSCI 2014) (2014, December)

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See detailBi-objective Optimization of Satellite Payload Power Configuration
Kieffer, Emmanuel UL; Stathakis, Apostolos UL; Danoy, Grégoire UL et al

in International Conference on Metaheuristics and Nature Inspired Computing (META 2014) (2014, October)

Detailed reference viewed: 68 (14 UL)