Most current P2P file sharing systems treat their users as anonymous, unrelated entities, and completely disregard any social relationships between them. However, social phenomena such as friendship and the existence of communities of users with similar tastes may be well exploited in such systems, to increase their usability and performance. In this paper we present a novel social-based P2P file-sharing paradigm that exploits social phenomena by maintaining social networks and using these in content discovery, content recommendation, and downloading. Based on this paradigm's first class concepts such as taste groups, friends, and friends-offriends, we have designed and implemented the TRIBLER P2P filesharing system as a set of extensions to Bittorrent. We present and discuss the design of TRIBLER, and we show evidence that TRIBLER enables fast, trusted content discovery and recommendation at a low additional overhead, and a significant improvement in download performance.

With the completion of the sequencing of the human genome, the need for tools capable of unraveling the interaction and functionality of genes becomes extremely urgent. In answer to this quest, the advent of microarray technology provides the opportunity to perform large scale gene expression analyses. Recently, genetic networks were proposed as a possible methodology for modeling genetic interactions. Since then, a wide variety of di erent models have been introduced. However, it is, in general, unclear what the strengths and weaknesses of each of these approaches are and where these models overlap and di er. This paper compares di erent genetic modeling approaches that attempt to extract the gene regulation matrix from expression data. A taxonomy of continuous genetic network models is proposed and the following important c haracteristics are suggested and employed to compare the models: 1 inferential power; 2 predictive p o w er; 3 robustness; 4 consistency; 5 stability and 6 computational cost. Where possible, synthetic time series data are employed to investigate some of these properties.

No abstract

No abstract

No abstract