We study budget constrained network upgrading problems. We are given an undirected edge weighted graph G V E where node v V can be upgraded at a cost of c v . This upgrade reduces the weight of each edge incident on v. The goal is to find a minimum cost set of nodes to be upgraded so that the resulting network has a minimum spanning tree of weight no more than a given budget D. The results obta...

In the k-dispersion problem, we need to select k nodes of a given graph so as to maximize the minimum distance between any two chosen nodes. This can be seen as a generalization of the independent set problem, where the goal is to select nodes so that the minimum distance is larger than 1. We design an optimal O(n) time algorithm for the dispersion problem on trees consisting of n nodes, thus i...

We introduce energy models for drawing clustered small-world graphs. Clustered means that there exist (probably unknown) sets of nodes with many edges between nodes of the same set and few edges to nodes outside the set. Small-world means that the graph-theoretic distances between nodes are small relative to the number of nodes. Previous force or energy models do not produce satisfactory result...

This paper investigates connectivity in one-dimensional ad hoc networks by means of the distribution of the minimum hop count between source and destination nodes. We derive the exact probability distribution of the minimum hop count from the location density of relay nodes in the multihop path selected with the Most Forward within Radius (MFR) scheme. The probability that the source and destin...

network sensors consist of sensor nodes in which every node covers a limited area. the most common use ofthese networks is in unreachable fields.sink is a node that collects data from other nodes.one of the main challenges in these networks is the limitation of nodes battery (power supply). therefore, the use oftopology control is required to decrease power consumption and increase network acce...

Proof. Lets assume that there are two nodes u and v in depth d for which the calculated lower bound is optimal, and u is visited first among all nodes in depth d with optimal lower bound. This implies that the lower bound of v is not smaller than the lower bound of u. A best-first search Branch-and-Bound algorithm only visits nodes with lower bounds not greater than the global minimum. It follo...

introduction: lymphoscintigraphy is imaging of the lymphatic system and has been integrated into the sentinel node mapping procedures. lymphoscintigraphy usually encompasses early or delayed static images. however, immediate dynamic imaging of the lymphatic basins and tumors has also been used as an adjunct lymphoscintigraphy imaging. the aim of this study was to assess the role of early dynami...

In Mobile Ad-hoc Networks(MANETs), enabling communication among different domains is becoming one of the areas of research topics as Border Gateway Protocol (BGP) is not adequate to support MANETs (Mobile Ad-hoc Networks). BGP does not scale to mobile and topological environment [14]. So there is a need to develop an efficient inter-domain routing protocol for heterogeneous MANETs. This is to i...

background: the purpose of this study was to evaluate nodal irradiation with conventional three-field's technique. materials and methods: fifty patients with breast cancer were enrolled in this study. computed tomography scans in the supine treatment position were imported into a treatment planning system. levels i-iii axillary and supraclavicular nodes were identified and their depths to ...