Considerations about multistep community detection

The problem and implications of community detection in networks have raised a huge attention, for its important applications in both natural and social sciences. A number of algorithms has been developed to solve this problem, addressing either speed optimization or the quality of the partitions calculated. In this paper we propose a multi-step procedure bridging the fastest, but less accurate algorithms (coarse clustering), with the slowest, most effective ones (refinement). By adopting heuristic ranking of the nodes, and classifying a fraction of them as `critical', a refinement step can be restricted to this subset of the network, thus saving computational time. Preliminary numerical results are discussed, showing improvement of the final partition.Comment: 12 page

DiffuGreedy: An Influence Maximization Algorithm based on Diffusion Cascades

International audienceFinding a set of nodes that maximizes the spread in a network, known as the influence maximization problem, has been addressed from multiple angles throughout the literature. Traditional solutions focus on the algorithmic aspect of the problem and are based solely on static networks. However, with the emergence of several complementary data, such as the network's temporal changes and the diffusion cascades taking place over it, novel methods have been proposed with promising results. Here, we introduce a simple yet effective algorithm that combines the algorithmic methodology with the diffusion cascades. We compare it with four different prevalent influence maximization approaches, on a large scale Chinese microblogging dataset. More specifically, for comparison, we employ methods that derive the seed set using the static network, the temporal network, the diffusion cascades, and their combination. A set of diffusion cascades from the latter part of the dataset is set aside for evaluation. Our method outperforms the rest in both quality of the seed set and computational efficiency

Detecting and Ranking API Usage Pattern in Large Source Code Repository: A LFM Based Approach

Part 1: MAKE TopologyInternational audienceCode examples are key resources for helping programmers to learn correct Application Programming Interface (API) usages efficiently. However, most framework and library APIs fail in providing sufficient and adequate code examples in corresponding official documentations. Thus, it takes great programmers’ efforts to browse and extract API usage examples from websites. To reduce such effort, this paper proposes a graph-based pattern-oriented mining approach, LFM-OUPD (Local fitness measure for detecting overlapping usage patterns) for API usage facility, that recommends proper API code examples from data analytics. API method queries are accepted from programmers and corresponding code files are collected from related API dataset. The detailed structural links among API method elements in conceptual source codes are captured and generate a code graph structure. Lancichinetti et al. proposed an overlapping community detecting algorithm (Local fitness measure, LFM), based on the local optimization of a fitness function. In LFM-OUPD, a mining algorithm based on LFM is presented to explore the division of method sequences in the directed source code element graph and detect candidates of different API usage patterns. Then a ranking approach is applied to obtain appropriate API usage pattern and code example candidates. A case study on Google Guava is conducted to evaluate the effectiveness of this approach

A Distributed and Clustering-Based Algorithm for the Enumeration Problem in Abstract Argumentation

International audienceComputing acceptability semantics of abstract argumentation frameworks is receiving increasing attention. Large-scale instances, with a clustered structure, have shown particularly difficult to compute. This paper presents a distributed algorithm, AFDivider, that enumerates the acceptable sets under several labelling-based semantics. This algorithm starts with cutting the argumentation framework into clusters thanks to a spectral clustering method, before computing simultaneously in each cluster parts of the labellings. This algorithm is proven to be sound and complete for the stable, complete and preferred semantics, and empirical results are presented.Le calcul de l’acceptabilité dans les systèmes d’argumentation reçoit une attention croissante. Dans les systèmes de grande envergure, avec une structure en clusters, ce calculs e montre particulièrement difficile. Cet article présente un algorithme distribué, AFDivider, qui énumère les ensembles acceptables sous plusieurs sémantiques, en commençant par découper le système d’argumentation en clusters grâce à une méthode de partitionnement spectral, avant de calculer simultanément dans chaque partition des parties des en-sembles acceptables. Cet algorithme est prouvé correct et complet pour les sémantiques stable, complète et préférée,et des résultats empiriques sont présentés