Given a set of polygonal obstacles in the plane, the shortest watchman route problem asks for a closed route from which each point in the exterior of the polygons is visible to some point along the route. This problem is known to be NP-hard and the development of an eecient approximation algorithm is still open. We present an O(n 2) time algorithm for computing the shortest watchman route for a...

The Chinese Postman Problem in a multigraph is the problem of finding a shortest closed walk traversing all the edges. In a (2r + 1)-regular multigraph, the problem is equivalent to finding a smallest spanning subgraph in which all vertices have odd degree. In 1994, Kostochka and Tulai established a sharp upper bound for the solution. In this paper, we give simple proofs of their bounds for 3-r...

Since the discovery of the giant magnetoresistance (GMR) in magnetic multilayers, several theoretical descriptions have been used to determine the resistivity of such layered structures. The resistance for the current in direction of the planes of layers can easily be measured, and has been intensively studied theoretically. However, the investigation of the GMR for the current perpendicular to...

A graph is supereulerian if it has a spanning Eulerian subgraph. Motivated by the Chinese Postman Problem, Boesch, Suffel, and Tindell ([2]) in 1997 proposed the supereulerian problem, which seeks a characterization of graphs that have spanning Eulerian subgraphs, and they indicated that this problem would be very difficult. Pulleyblank ([71]) later in 1979 proved that determining whether a gra...

In this article, the theory of multidimensional linear attacks on block ciphers is developed and the basic attack algorithms and their complexity estimates are presented. As an application the multidimensional linear distinguisher derived by Cho for the block cipher PRESENT is discussed in detail.

Due to the way BGP paths are distributed over iBGP sessions inside an Autonomous System (AS), a BGP withdraw that follows a failure may be propagated outside the AS although other routers of the AS know a valid alternate path. This causes transient losses of connectivity and contributes to the propagation of a large number of unnecessary BGP messages. In this paper, we show, based on RouteViews...

In this paper, we present a fast and eficient compilation methodology for pipeline reconfigurable architectures. Our compiler back-end is much faster than conventional CAD tools, and fairly eficient. W e represent pipeline reconfigurable architectures by a generalized VLI W-like model. The complex architectural constraints are effectively expressed in terms of a single graph parameter: the rout...

We present an efficient algorithm that can distinguish the keystream of WPA from that of a generic instance of RC4 with a packet complexity of O(N), where N denotes the size of the internal permutation of RC4. In practice, our distinguisher requires approximately 2 packets; thus making it the best known distinguisher of WPA to date. This is a significantly improved distinguisher than the previo...

Abs t rac t . A binary clutter is the family of inclusionwise minimal supports of vectors of affine spaces over GF(2). Binary clutters generalize various objects studied in Combinatorial Optimization, such as paths, Chinese Postman Tours, multiflows and one-sided circuits on surfaces. The present work establishes connections among three matroids associated with binary clutters, and between any ...