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International audience; Graph clustering is one of the key techniques to understand structures that are presented in networks. In addition to clusters, bridges and outliers detection is also a critical task as it plays an important role in the analysis of networks. Recently, several graph clustering methods are developed and used in multiple application domains such as biological network analysis, recommendation systems and community detection. Most of these algorithms are based on the structural clustering algorithm. Yet, this kind of algorithm is based on the structural similarity. This latter requires to parse all graph’ edges in order to compute the structural similarity. However, the height needs of similarity computing make this algorithm more adequate for small graphs, without significant support to deal with large-scale networks. In this paper, we propose a novel distributed graph clustering algorithm based on structural graph clustering. The experimental results show the efficiency in terms of running time of the proposed algorithm in large networks compared to existing structural graph clustering methods.

Big graphs are so large that their analysis often rely on the cloud for parallel processing. Data placement, as a key pre-processing step, has a profound impact on the performance of parallel processing. Traditional placement methods fail to preserve graph topologies, leading to poor performance. As the community is the most common structure of big graphs, in this work, we present a two-phase community-aware placement algorithm to place big graphs into the cloud for parallel processing. It can obtain a placement scheme that preserves the community structure well by maximizing the modularity density of the scheme under memory capacity constraints of computational nodes of the cloud in two phases. In the first phase, we design a streaming partitioning heuristic to detect communities based on partial and incomplete graph information. They form an initial placement scheme with relatively high modularity density. To improve it further, in the second phase, we put forward a scale-constrained kernel k-means algorithm. It takes as input the initial placement scheme and iteratively redistributes graph vertices across computational nodes under scale constraints until the modularity density cannot be improved any further. Finally, experiments show that our algorithm can preserve graph topologies well and greatly support parallel processing of big graphs in the cloud.

Graph data analysis is a hot topic in recent research area. Graph classification is one of the most important graph data analysis problems, which choose the most probable class labels of graphs using models based on the training dataset. It has wildly applications in protein group identification, chemical compounds classification and so on. Many existing research of graph learning suffer from high computation cost as large scale graph data are dramatically increased. In order to realize big graph classification with real-time learning ability and good scalability, efficient feature extraction approaches and ELM variants are utilized in this paper. To be specific, we present three frameworks of big graph classification based on ELMs: (1) a framework with a compression-based frequent subgraph mining method to reduce graph size; (2) an incremental framework to handle dynamic graphs; (3) a distributed framework with distributed ELMs to provide good scalability and easy implementation on cloud platforms. Extensive experiments are conducted on clusters with large real-world graph datasets. The experimental results demonstrate that our frameworks are efficient in big graph classification applications, and well suitable for dynamic networks. The results also validate that ELM and its variants have good classification performance on large-scale graphs.

Graph computing is widely applied in a large number of big data applications. Despite its importance, high performance graph computing remains a challenge, especially for large-scale graphs. In this paper, by analyzing from the architectural perspective, we study computational behaviors of graph computing in real-world use cases. We benchmark a set of representative graph algorithms implemented on a unified framework and conduct experiments to analyze comprehensive performance characteristics. In the characterization, we observed multiple insights, including irregular memory patterns, significant diverse behavior across different computations, highly data dependent behaviors, etc., using large-scale synthetic and real-world graphs. To the best of our knowledge, this is the first comprehensive architectural study on the full-scope of graph computing. It can improve our understanding on graph computing and help high performance computing research for graph-based big data applications.

We propose a new design of universal designated verifier transitive signatures, to authenticate dynamically growing big graph data. The scheme is built on the classical RSA signature and possesses several desirable properties. It supports edge-signature composition as transitive signatures, i.e., with the signatures of two adjacent edges ( i , j ) and ( j , k ) , one can obtain a valid signature of the edge ( i , k ) . Additionally, a signature holder can convince only one designated verifier about the existence of an edge. Our design can efficiently achieve a tradeoff between data authenticity (when publishing dynamically growing big graph data) and data privacy (when disseminating big graph data).