Obstacle representations of graphs have been investigated quite intensely over the last few years. We focus on graphs that can be represented by a single obstacle. Given a (topologically open) polygon C and a finite set P of points in general position in the complement of C, the visibility graph GC(P ) has a vertex for each point in P and an edge pq for any two points p and q in P that can see ...

Bile ducts are hepatic tubular structures that are lined by cholangiocytes, a type of liver epithelial cell. Cholangiocytes first form a single layer of cells, termed the ductal plate, surrounding the portal vein, which eventually remodels into the branching tubular network of bile ducts. The process of bile duct morphogenesis is not yet clear: a conventional model where cholangiocytes prolifer...

This work presents a magnetron with sputtering unit (sandwich target). The novel-$$$ty of the is due to three parallel plates different metals included in unit. They are mounted on same axis and rigidly attached it. located reactive environment consisting plasma-forming argon gas (nitrogen, oxy-$$$gen, etc.). lower plate cold, while middle outer ones operate hot target mode. In erosion zone pla...

Deciding whether a collection of unrooted trees is compatible is a fundamental problem in phylogenetics. Two different graph-theoretic characterizations of tree compatibility have recently been proposed. In one of these, tree compatibility is characterized in terms of the existence of a specific kind of triangulation in a structure known as the display graph. An alternative characterization exp...

The P4-sparse Graph Sandwich Problem asks, given two graphs G 1 = (V, E1) and G2 = (V, E2), whether there exists a graph G = (V, E) such that E1 ⊆ E ⊆ E2 and G is P4-sparse. In this paper we present a polynomial-time algorithm for solving the Graph Sandwich Problem for P4-sparse graphs. c © 2008 Elsevier B.V. All rights reserved.

In this paper we introduce the simultaneous membership problem, defined for any graph class C characterized in terms of representations, e.g. any class of intersection graphs. Two graphs G1 and G2, sharing some vertices X (and the corresponding induced edges), are said to be simultaneous members of graph class C, if there exist representations R1 and R2 of G1 and G2 that are “consistent” on X ....

A graph is a 1-join composition if its vertex set can be partitioned into four nonempty sets AL; AR ; SL and SR such that: every vertex of AL is adjacent to every vertex of AR; no vertex of SL is adjacent to vertex of AR∪SR; no vertex of SR is adjacent to a vertex of AL∪SL. The graph sandwich problem for 1-join composition is de9ned as follows: Given a vertex set V , a forced edge set E, and a ...

A study on the static analysis of a naval panel made composite sandwich materials is presented. By using FEM, modeling floor with length 5 m and width 2.5 performed. Two distinct cases, have been performed: first model consists plate stiffeners steel second concerns material type / SANFoam103 steel, steel. parametric has The thickness faces 6 mm, for core SANFoam selected thicknesses 10 20 40 mm.

Abstract Based on the technical study of a composite vertical tail, mechanical properties honeycomb sandwich structure at leading edge were studied fundamental computational analysis. The stress calculation and modal analysis beam/plate are carried out by using engineering algorithm two finite element modeling methods. comparative results shows that methods can effectively simulate structure. I...