Learn More
We formalize a potentially rich new streaming model, the semi-streaming model, that we believe is necessary for the fruitful study of efficient algorithms for solving problems on massive graphs whose edge sets cannot be stored in memory. In this model, the input graph, G = (V, E), is presented as a stream of edges (in adversarial order), and the storage(More)
The notion of blacklisting communication sources has been a well-established defensive measure since the origins of the Internet community. In particular, the practice of compiling and sharing lists of the worst offenders of unwanted traffic is a blacklisting strategy that has remained virtually unques-tioned over many years. But do the individuals who(More)
We investigate the importance of space when solving problems based on graph distance in the streaming model. In this model, the input graph is presented as a stream of edges in an arbitrary order. The main computational restriction of the model is that we have limited space and therefore cannot store all the streamed data; we are forced to make(More)
Detecting anomalous BGP-route advertisements is crucial for improving the security and robustness of the Internet's interdomain-routing system. In this paper, we propose an instance-learning framework that identifies anomalies based on deviations from the "normal" BGP-update dynamics for a given destination prefix and across prefixes. We employ wavelets for(More)
We investigate the diameter problem in the streaming and sliding-window models. We show that, for a stream of n points or a sliding window of size n, any exact algorithm for diameter requires Ω(n) bits of space. We present a simple ǫ-approximation 1 algorithm for computing the diameter in the streaming model. Our main result is an ǫ-approximation algorithm(More)
We explore problems related to computing graph distances in the data-stream model. The goal is to design algorithms that can process the edges of a graph in an arbitrary order given only a limited amount of working memory. We are motivated by both the practical challenge of processing massive graphs such as the web graph and the desire for a better(More)
For an unweighted undirected graph G exists an integer β = β(, κ) such that for every n-vertex graph G there exists a (1 + , β)-spanner G with O(n 1+1/κ) edges. An efficient distributed protocol for constructing (1+ , β)-spanners was devised in [18]. The running time and the communication complexity of that protocol are O(n 1+ρ) and O(|E|n ρ), respectively,(More)
Network security has been a serious concern for many years. For example, firewalls often record thousands of exploit attempts on a daily basis. Network administrators could benefit from information on potential aggressive attack sources, as such information can help to proactively defend their networks. For this purpose , several large-scale information(More)
AI techniques play an important role in automated malware classification. Several machine-learning methods have been applied to classify or cluster malware into families, based on different features derived from dynamic review of the malware. While these approaches demonstrate promise, they are themselves subject to a growing array of counter measures that(More)