1,721,046 research outputs found
Designing reliable algorithms in unreliable memories
No full textSome of today's applications run on computer platforms with large and inexpensive memories, which are also error-prone. Unfortunately, the appearance of even very few memory faults may jeopardize the correctness of the computational results. An algorithm is resilient to memory faults if, despite the corruption of some memory values before or during its execution, it is nevertheless able to get a correct output at least on the set of uncorrupted values. In this paper we will survey some recent work on reliable computation in the presence of memory faults. © Springer-Verlag Berlin Heidelberg 2005
Budgeted matching and budgeted matroid intersection via the gasoline puzzle
Full text linkMany polynomial-time solvable combinatorial optimization problems become NP-hard if an additional complicating constraint is added to restrict the set of feasible solutions. In this paper, we consider two such problems, namely maximum-weight matching and maximum-weight matroid intersection with one additional budget constraint. We present the first polynomial-time approximation schemes for these problems. Similarly to other approaches for related problems, our schemes compute two solutions to the Lagrangian relaxation of the problem and patch them together to obtain a near-optimal solution. However, due to the richer combinatorial structure of the problems considered here, standard patching techniques do not apply. To circumvent this problem, we crucially exploit the adjacency relations on the solution polytope and, surprisingly, the solution to an old combinatorial puzzle. © 2009 Springer and Mathematical Programming Society
(1 + ε)-approximate incremental matching in constant deterministic amortized time
Full text linkWe study the matching problem in the incremental setting, where we are given a sequence of edge insertions and aim at maintaining a near-maximum cardinality matching of the graph with small update time. We present a deterministic algorithm that, for any constant ε > 0, maintains a (1 + ε)-approximate matching with constant amortized update time per insertion
Budgeted matching and budgeted matroid intersection via the gasoline puzzle
No full textMany polynomial-time solvable combinatorial optimization problems become NP-hard if an additional complicating constraint is added to restrict the set of feasible solutions. In this paper, we consider two such problems, namely maximum-weight matching and maximum-weight matroid intersection with one additional budget constraint. We present the first polynomial-time approximation schemes for these problems. Similarly to other approaches for related problems, our schemes compute two solutions to the Lagrangian relaxation of the problem and patch them together to obtain a near-optimal solution. However, due to the richer combinatorial structure of the problems considered here, standard patching techniques do not apply. To circumvent this problem, we crucially exploit the adjacency relations on the solution polytope and, surprisingly, the solution to an old combinatorial puzzle. © 2008 Springer-Verlag Berlin Heidelberg
A short proof of the VPN tree Routing conjecture on ring networks
Full text linkOnly recently, Hurkens, Keijsper, and Stougie proved the VPN Tree Routing Conjecture for the special case of ring networks. We present a short proof of a slightly stronger result which might also turn out to be useful for proving the VPN Tree Routing Conjecture for general networks
- …
