Tomasz Radzik

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We conduct an extensive computational study of shortest paths algorithms, including some very recent algorithms. We also suggest new algorithms motivated by the experimental results and prove interesting theoretical results suggested by the experimental data. Our computational study is based on several natural problem classes which identify strengths and(More)
We prove a tight Θ(min(nm log(nC), nm2)) bound on the number of iterations of the minimum-mean cycle-canceling algorithm of Goldberg and Tarjan [13]. We do this by giving the lower bound and by improving the strongly polynomial upper bound on the number of iterations toO(nm 2). We also give an improved version of the maximum-mean cut canceling algorithm of(More)
We consider the generalized network flow problem. Each arc e in the network has a gain factor y (e ) . If f ( e ) units of flow enter arc e , then f ( e ) r ( e ) units arrive at the other end of e. The generalized network flow problem is to maximize the net flow into one specific node, the sink. -We give an algorithm which solves this problem in O(m2 (m +(More)
Radio networks model wireless data communication when the bandwidth is limited to one wave frequency. The key restriction of such networks is mutual interference of packets arriving simultaneously at a node. The many-to-many (m2m) communication primitive involves p participant nodes from among n nodes in the network, where the distance between any pair of(More)
A recommender system uses information about known associations between users and items to compute for a given user an ordered recommendation list of items which this user might be interested in acquiring. We consider ordering rules based on various parameters of random walks on the graph representing associations between users and items. We experimentally(More)
We study properties of multiple random walks on a graph under various assumptions of interaction between the particles. To give precise results, we make the analysis for random regular graphs. The cover time of a random walk on a random r-regular graph was studied in [6], where it was shown with high probability (whp), that for r ≥ 3 the cover time is(More)