We study the problem of optimizing the spanning tree of a set of points in IR3, whose projection onto a given plane contains no crossing edges. Denoted by NCMST (which stands for non-crossing minimum spanning trees), this problem is defined as follows. Given a set of points P in IR and a plane F , find a spanning tree whose projection onto F contains no crossing edges and its length is minimum ...

We present a generalization of the Steiner problem in a directed graph. Given nonnegative weights on the arcs, the problem is to find a minimum weight subset F of the arc set such that the subgraph induced by F contains a given number of arc-disjoint directed paths from a certain root node to each given terminal node. Some applications of the problem are discussed and properties of associated p...

We present an extensive experimental study comparing the performance of four algorithms for the following orthogonal segment intersection problem: given a set of horizontal and vertical line segments in the plane, report all intersecting horizontal-vertical pairs. The problem has important applications in VLSI layout and graphics, which are large-scale in nature. The algorithms under evaluation...

objectives to compare an out-of-plane interscalene catheter technique to the in-plane technique in a randomized clinical trial. patients and methods eighty-four patients undergoing open shoulder surgery were randomized to either the in-plane or out-of-plane ultrasound-guided continuous interscalene technique. the primary outcome was vas pain rating at 24 hours. secondary outcomes included pain ...

Given a set of points, we define a minimum Steiner point tree to be a tree interconnecting these points and possibly some additional points such that the length of every edge is at most 1 and the number of additional points is minimized. We propose using Steiner minimal trees to approximate minimum Steiner point trees. It is shown that in arbitrary metric spaces this gives a performance differe...

We investigate the exploration of networks by a mobile agent. It is long known that, without global information about the graph, it is not possible to make the agent halts after the exploration except if the graph is a tree. We therefore endow the agent with binoculars, a sensing device that can show the local structure of the environment at a constant distance of the agent current location. We...

This paper presents a two-tiered reliable application layer multicast (ALM) solution, called HRALM, to provide lossless ALM services. HRALM builds a domain-based multicast tree, and divides the members into two transport planes (i.e., Plane 1 and Plane 2) in terms of the tree. In any domain, the distance between each member and the domain header is below a given threshold, which improves the ca...

Remote sensing of forest canopies is dominated by the interaction between tree trunks and ground at lower microwave frequencies and/or when the crown layer is tenuous. An e cient and complete electromagnetic scattering model for tree trunks above a tilted rough ground plane has been performed and enhanced. The individual trunks are modelled as nite-length strati ed cylinders, with an external c...

This paper presents a simple method to render complex trees on high frame rates while maintaining parallax effects. Based on the recognition that a planar impostor is accurate if the represented polygon is in its plane, we find an impostor for each of those groups of tree leaves that lie approximately in the same plane. The groups are built automatically by a clustering algorithm. Unlike billbo...

The one-loop effective potential in 2D dilaton gravity in conformal gauge on the topologically non-trivial plane IR×S and on the hyperbolic plane H/Γ is calculated. For arbitrary choice of the tree scalar potential it is shown, that the one-loop effective potential explicitly depends on the reference metric (through the dependence on the radius of the torus or the radius of H/Γ). This phenomeno...