Alessandro Panconesi

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We have observed that the cost of the search is equal to the number of tosses of a coin of bias p that are necessary until we obtain H successes. That is, we flip the coin repeatedly and stop as soon as we observe H successes. The difficulty here is that the random variable we are studying is the sum of geometrically distributed random variables. The(More)
Certain types of routing, scheduling, and resource-allocation problems in a distributed setting can be modeled as edge-coloring problems. We present fast and simple randomized algorithms for edge coloring a graph in the synchronous distributed point-to-point model of computation. Our algorithms compute an edge coloring of a graph G with n nodes and maximum(More)
We give, for the first time, a precise mathematical analysis of the connectivity and security properties of sensor networks that make use of the random predistribution of keys. We also show how to set the parameters---pool and key ring size---in such a way that the network is not only connected with high probability via secure links but also provably(More)
Motivated by structural properties of the Web graph that support efficient data structures for in memory adjacency queries, we study the extent to which a large network can be compressed. Boldi and Vigna (WWW 2004), showed that Web graphs can be compressed down to three bits of storage per edge; we study the compressibility of social networks where again(More)
Sybil attacks in which an adversary forges a potentially unbounded number of identities are a danger to distributed systems and online social networks. The goal of sybil defense is to accurately identify sybil identities. This paper surveys the evolution of sybil defense protocols that leverage the structural properties of the social graph underlying a(More)
We introduce a formal framework for studying approximation properties of NP optimization (NPO) problems. The classes of approximable problems we consider are those appearing in the literature, namely the class of approximable problems within a constant E (APX), and the class of problems having a polynomial time approximation scheme (PTAS). We define natural(More)
We show that if a connected graph with $n$ nodes has conductance &#966; then rumour spreading, also known as randomized broadcast, successfully broadcasts a message within ~O(&#966;<sup>-1</sup> &#8226; log n), many rounds with high probability, regardless of the source, by using the PUSH-PULL strategy. The ~O(&#8226;&#8226;) notation hides a polylog(More)
We give simple, deterministic, distributed algorithms for computing maximal matchings, maximal independent sets and colourings. We show that edge colourings with at most $2\Delta-1$ colours, and maximal matchings can be computed within ${\cal O}(\log^* n + \Delta)$ deterministic rounds, where $\Delta$ is the maximum degree of the network. We also show how(More)