Mikael Hammar

Learn More
Summary form only given. We study on-demand source initiated protocols for mobile wireless networks. In particular, we study the flooding procedure commonly used by these protocols to set up temporary communication paths. The benefit of the flooding technique is its generosity regarding changes in network structure. On the other hand, each time a message is(More)
PURPOSE To assess the value of ultrasonography (US) in the preoperative evaluation of patients with anterior shoulder instability. MATERIALS AND METHODS Twenty-two patients with one-sided anterior shoulder instability were examined with US by using three dynamic scanning approaches: two frontal and one axillary. The anterior labrum, the anterior(More)
A watchman route in a polygon P is a route inside P such that each point in the interior of P is visible from at least one point along the route. The objective of the shortest watchman route problem is to minimize the length of the watchman route for a given polygon. In 1991 Chin and Ntafos claimed an O(n 4) algorithm, solving the shortest watchman route(More)
In this paper we investigate parallel searching on m concurrent rays. We assume that a target t is located somewhere on one of the rays and that a group of m point robots has to reach t. Furthermore, we assume that the robots have no way of communicating over distance. Given a strategy S we are interested in the competitive ratio which is deened as the(More)
A box-tree is a \ifasci so-called \emph{bounding-volume hierarchy} \else bounding-volume hierarchy \fi that uses axis-aligned boxes as bounding volumes. The query complexity of a box-tree with respect to a given type of query is the maximum number of nodes visited when answering such a query. We describe several new algorithms for constructing box-trees(More)