2012
Authors
Ribeiro, P; Silva, F; Lopes, L;
Publication
JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING
Abstract
Many natural structures can be naturally represented by complex networks. Discovering network motifs, which are overrepresented patterns of inter-connections, is a computationally hard task related to graph isomorphism. Sequential methods are hindered by an exponential execution time growth when we increase the size of motifs and networks. In this article we study the opportunities for parallelism in existing methods and propose new parallel strategies that adapt and extend one of the most efficient serial methods known from the Fanmod tool. We propose both a master-worker strategy and one with distributed control, in which we employ a randomized receiver initiated methodology capable of providing dynamic load balancing during the whole computation process. Our strategies are capable of dealing both with exact and approximate network motif discovery. We implement and apply our algorithms to a set of representative networks and examine their scalability up to 128 processing cores. We obtain almost linear speedups, showcasing the efficiency of our proposed approach and are able to reach motif sizes that were not previously achievable using conventional serial algorithms.
2007
Authors
Ribeiro, P; Pereira, P; Lopes, L; Silva, F;
Publication
IBERGRID: 1ST IBERIAN GRID INFRASTRUCTURE CONFERENCE PROCEEDINGS
Abstract
We present an architecture that allows the seamless configuration of computer labs to work as dedicated computing clusters during periods of user inactivity. The operation of the cluster is fully automated by making use of differentiated network booting and a job management system. We have prepared it to be plugged to a larger computational grid. We provide some preliminary performance results obtained.
2023
Authors
Oliveira, HS; Ribeiro, PP; Oliveira, HP;
Publication
Pattern Recognition and Image Analysis - 11th Iberian Conference, IbPRIA 2023, Alicante, Spain, June 27-30, 2023, Proceedings
Abstract
2023
Authors
Ferreira, J; Barbosa, A; Ribeiro, P;
Publication
COMPLEX NETWORKS AND THEIR APPLICATIONS XI, COMPLEX NETWORKS 2022, VOL 2
Abstract
Many complex systems exist in the physical world and therefore can be modeled by networks in which their nodes and edges are embedded in space. However, classical network motifs only use purely topological information and disregard other features. In this paper we introduce a novel and general subgraph abstraction that incorporates spatial information, therefore enriching its characterization power. Moreover, we describe and implement a method to compute and count our spatial subgraphs in any given network. We also provide initial experimental results by using our methodology to produce spatial fingerprints of real road networks, showcasing its discrimination power and how it captures more than just simple topology.
2021
Authors
Eddin, AN; Bono, J; Aparício, D; Polido, D; Ascensão, JT; Bizarro, P; Ribeiro, P;
Publication
CoRR
Abstract
2023
Authors
Barbosa, A; Ribeiro, P; Dutra, I;
Publication
COMPLEX NETWORKS AND THEIR APPLICATIONS XI, COMPLEX NETWORKS 2022, VOL 2
Abstract
Association Football is probably the world's most popular sport. Being able to characterise and compare football players is therefore a very important and impactful task. In this work we introduce spatial flow motifs as an extension of previous work on this problem, by incorporating both temporal and spatial information into the network analysis of football data. Our approach considers passing sequences and the role of the player in those sequences, complemented with the physical position of the field where the passes occurred. We provide experimental results of our proposed methodology on real-life event data from the Italian League, showing we can more accurately identify players when compared to using purely topological data.
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