Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-0171 Approximating the Distortion

Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-519 Network discovery on snapshots of the internet graph

Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-0023 An Experimental Study of Random Knapsack Problems

The size of the Pareto curve for the bicriteria version of the knapsack problem is polynomial on average. This has been shown for various random input distributions. We experimentally investigate the number of Pareto optimal knapsack fillings. Our experiments suggests that the theoretically proven upper bound of O(n3) for uniform instances and O(φμn4) for general probability distributions is no...

Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-0295 Bookmark-driven Query Routing in Peer-to-Peer Web Search

We consider the problem of collaborative Web search and query routing strategies in a peer-to-peer (P2P) environment. In our architecture every peer has a full-fledged search engine with a (thematically focused) crawler and a local index whose contents may be tailored to the user’s specific interest profile. Peers are autonomous and post meta-information about their bookmarks and index lists to...

Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-0310 Local View Attack on Anonymous Communication

We consider anonymous communication protocols based on onions: each message is sent in an encrypted form through a path chosen at random by its sender, and the message is re-coded by each server on the path. Recently, it has been shown that if the anonymous paths are long enough, then the protocols provide provable security for some adversary models. However, it was assumed that all users choos...

Integrated Project Member of the FET Proactive Initiative Complex Systems DELIS-TR-0052 Nash Equilibria in Discrete Routing Games with Convex Latency Functions

We study Nash equilibria in a discrete routing game that combines features of the two most famous models for non-cooperative routing, the KP model [16] and the Wardrop model [27]. In our model, users share parallel links. A user strategy can be any probability distribution over the set of links. Each user tries to minimize its expected latency, where the latency on a link is described by an arb...