We present eecient polynomial time algorithms that place bn=2c vertex guards which cover the surface of an n-vertex polyhedral terrain, and similarly, bn=3c edge guards which cover the surface of an n-vertex polyhedral terrain. The time complexity of both algorithms, dominated by the cost of nding a maximum matching in a graph, is O(n 3=2).

We investigate the complexity of the satisfiability problem for the two-variable guarded fragment with transitive guards.We prove that the satisfiability problem for the monadic version of this logic without equality is 2EXPTIME-hard. It is in fact 2EXPTIME-complete, since as shown by Szwast and Tendera, the whole guarded fragment with transitive guards is in 2EXPTIME.We also introduce a new lo...

This paper considers the construction of Petri nets to simulate conditional computation in various forms of systems. Coloured Petri nets underly the definition of a family of Petri nets based on rough set theory. Multivalued logic provides the basis for a family of guards on transitions with a form of continuous enabling. The notion of levelof-enabling of transitions is introduced. A second fam...

In this work, we introduce the Minimum Trilateration Problem, the problem of placing distance measuring guards in a polygon in order to locate points in the interior. We provide the first non-trivial bounds on trilaterating simple polygons, by showing that b 8N 9 c guards suffice for any non-degenerate polygon of N sides, and present an O(N logN) algorithm for the corresponding placement. We al...

OBJECTIVE To systematically review studies that examined the effectiveness of wrist guards in preventing wrist injuries among snowboarders. DATA SOURCE MEDLINE (1966-March 2005), EMBASE (1988-March 2005), Cochrane (2005 Issue 1), Sport Discus (1975-March 2005) were searched using variations of the term "snowboard." PubMED was searched for the year 2005 to capture any recently published studie...

The purpose of the present study was to compare chosen physical fitness characteristics of Turkish professional basketball players in different divisions (first and second division) and playing positions. Forty-five professional male basketball players (14 guards, 15 forwards, 16 centers) participated in this study voluntarily. For each player, anthropometric measurements were performed, as wel...

The Parameterized Model Checking Problem (PMCP) is to decide whether a temporal property holds for a uniform family of systems, , comprised of a control process, , and finitely, but arbitrarily, many copies of a user process, , executing concurrently with interleaving semantics. We delineate the decidability/undecidability boundary of the PMCP for all possible systems that arise by letting proc...