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How to spot and summarize anomalies in dynamic networks such as road networks, communication networks and social networks? An anomalous event, such as a traffic accident, a denial of service attack or a chemical spill, can affect several nearby edges and make them behave abnormally, over several consecutive time-ticks. We focus on spotting and summarizing(More)
BACKGROUND Finding the subgraphs of a graph database that are isomorphic to a given query graph has practical applications in several fields, from cheminformatics to image understanding. Since subgraph isomorphism is a computationally hard problem, indexing techniques have been intensively exploited to speed up the process. Such systems filter out those(More)
Network querying is a growing domain with vast applications ranging from screening compounds against a database of known molecules to matching sub-networks across species. Graph indexing is a powerful method for searching a large database of graphs. Most graph indexing methods to date tackle the exact matching (isomorphism) problem, limiting their(More)
—In Delay Tolerant Networks (DTNs), end-to-end connectivity between nodes does not always occur due to limited radio coverage, node mobility and other factors. Remote communication may assist in guaranteeing delivery. However, it has a considerable cost, and consequently, minimizing it is an important task. For multicast routing, the problem is NP-hard, and(More)
Networks from different genres are not static entities, but exhibit dynamic behavior. The congestion level of links in transportation networks varies in time depending on the traffic. Similarly, social and communication links are employed at varying rates as information cascades unfold. In recent years there has been an increase of interest in modeling and(More)
BACKGROUND Biomedical and chemical databases are large and rapidly growing in size. Graphs naturally model such kinds of data. To fully exploit the wealth of information in these graph databases, a key role is played by systems that search for all exact or approximate occurrences of a query graph. To deal efficiently with graph searching, advanced methods(More)
Sequence-based comparisons have been the workhorse of bioinformatics for the past four decades, furthering our understanding of gene function and evolution. Over the last decade, a plethora of technologies have matured for measuring Protein-protein interactions (PPIs) at large scale, yielding comprehensive PPI networks for over ten species. In this chapter,(More)
Anomaly detection in dynamic networks has a rich gamut of application domains, such as road networks, communication networks and water distribution networks. An anomalous event, such as a traffic accident, denial of service attack or a chemical spill, can cause a local shift from normal behavior in the network state that persists over an interval of time.(More)
Processes within real world networks evolve according to the underlying graph structure. A number of examples exists in diverse network genres: botnet communication growth, moving traffic jams [1], information foraging [2] in document networks (WWW and Wikipedia), and spread of viral memes or opinions in social networks. The network structure in all the(More)