Harald Räcke

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A principle task in parallel and distributed systems is to reduce the communication load in the interconnection network, as this is usually the major bottleneck for the performance of distributed applications. In this paper we introduce a framework for solving on-line problems that aim to minimize the congestion (i.e. the maximum load of a network link) in(More)
In this paper we consider the problem of (<i>k</i>, <i>&#965;</i>)-balanced graph partitioning - dividing the vertices of a graph into <i>k</i> almost equal size components (each of size less than <i>&#965;</i> &#8226; <i>n</i>&lt;over&gt;<i>k</i>) so that the capacity of edges between different components is minimized. This problem is a natural(More)
We analyze a randomized pursuit-evasion game on graphs. This game is played by two players, a hunter and a rabbit. Let G be any connected, undirected graph with n nodes. The game is played in rounds and in each round both the hunter and the rabbit are located at a node of the graph. Between rounds both the hunter and the rabbit can stay at the current node(More)
We study rerouting policies in a dynamic round-based variant of a well known game theoretic traffic model due to Wardrop. Previous analyses (mostly in the context of selfish routing) based on Wardrop's model focus mostly on the static analysis of equilibria. In this paper, we ask the question whether the population of agents responsible for routing the(More)
Consider the following network design problem: given a network <i>G = (V, E)</i>, source-sink pairs {<i>s</i><inf><i>i</i></inf>, <i>t</i><inf><i>i</i></inf>} arrive and desire to send a unit of flow between themselves. The cost of the routing is this: if edge <i>e</i> carries a total of <i>f</i><inf><i>e</i></inf> flow (from all the terminal pairs), the(More)
In a (randomized) oblivious routing scheme the path chosen for a request between a source <i>s</i> and a target <i>t</i> is independent from the current traffic in the network. Hence, such a scheme consists of probability distributions over <i>s-t</i> paths for every source-target pair <i>s,t</i> in the network.In a recent result [11] it was shown that for(More)
We give almost tight bounds for the online reordering buffer management problem on the uniform metric. Specifically, we present the first non-trivial lower bounds for this problem by showing that deterministic online algorithms have a competitive ratio of at least &#937;(&#8730;{log k/log log k}) and randomized online algorithms have a competitive ratio of(More)