scholarly journals On the proper orientation number of chordal graphs

2021 ◽  
Author(s):  
J. Araujo ◽  
A. Cezar ◽  
C.V.G.C. Lima ◽  
V.F. dos Santos ◽  
A. Silva
Keyword(s):  
Chordal Graphs ◽  
Proper Orientation

scholarly journals Proper Orientations of Chordal Graphs

2020 ◽  
Author(s):  
Julio Araujo ◽  
Alexandre Cezar ◽  
Carlos Vinícius Gomes Costa Lima ◽  
Vinicius Fernandes Dos Santos ◽  
Ana Shirley Ferreira Silva
Keyword(s):  
Upper Bound ◽  
Linear Time ◽  
Time Algorithm ◽  
Chordal Graphs ◽  
Linear Time Algorithm ◽  
Threshold Graphs ◽  
Minimum Integer ◽  
Split Graphs ◽  
Np Complete ◽  
Proper Orientation

An orientation D of a graph G = (V, E) is a digraph obtained from G by replacing each edge by exactly one of the two possible arcs with the same end vertices. For each v ∈ V(G), the indegree of v in D, denoted by dD−(v), is the number of arcs with head v in D. An orientation D of G is proper if dD−(u) ≠ dD−(v), for all uv ∈ E(G). An orientation with maximum indegree at most k is called a k-orientation. The proper orientation number of G, denoted by χ→(G), is the minimum integer k such that G admits a proper k-orientation. We prove that determining whether χ→(G) ≤ k is NP-complete for chordal graphs of bounded diameter. We also present a tight upper bound for χ→(G) on split graphs and a linear-time algorithm for quasi-threshold graphs.

Note on (semi-)proper orientation of some triangulated planar graphs

2021 ◽  
Vol 392 ◽  
pp. 125723
Author(s):  
Ruijuan Gu ◽  
Hui Lei ◽  
Yulai Ma ◽  
Zhenyu Taoqiu
Keyword(s):  
Planar Graphs ◽  
Proper Orientation

Chordal graphs

2021 ◽  
pp. 130-151
Author(s):  
Martin Charles Golumbic
Keyword(s):  
Chordal Graphs

On 3-Degree 4-Chordal Graphs

2020 ◽  
Author(s):  
Devarshi Aggarwal ◽  
R.Mahendra Kumar ◽  
Shwet Prakash ◽  
N. Sadagopan
Keyword(s):  
Chordal Graphs

scholarly journals Fabrication of Customized Sectional Impression Trays in Management of Patients with Limited Mouth Opening: A Simple and Unique Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Vamsi Krishna CH ◽  
K. Mahendranadh Reddy ◽  
Nidhi Gupta ◽  
Y. Mahadev Shastry ◽  
N. Chandra Sekhar ◽  
...  
Keyword(s):  
Case Reports ◽  
Mouth Opening ◽  
Limited Mouth Opening ◽  
Significant Step ◽  
Removable Prosthesis ◽  
Unique Approach ◽  
Submucous Fibrosis ◽  
The Common ◽  
Proper Orientation

Impression making is not only important but is also the most significant step in the fabrication of any fixed or removable prosthesis. Proper impression making may be hindered by certain pathologic conditions. Reduced mouth opening is one of the common mechanical obstructions for proper orientation of the impression tray in the patient’s mouth. In patients with trismus induced by submucous fibrosis, the procedure may be even more difficult to carry out because of reduced tissue resiliency and obliteration of vestibular spaces. Use of sectional trays offers one of the alternatives to overcome the problem of restricted mouth opening. Fabrication of customized impression trays according to the patient dentition improves the accuracy of impression making. The present case reports describe the fabrication of sectional custom trays designed for dentulous patients with chronic tobacco-induced submucous fibrosis.

scholarly journals Efficiency estimation for permanent magnets of synchronous wind generators

2014 ◽  
Vol 51 (1) ◽  
pp. 21-31 ◽  
Author(s):  
A. Serebryakov ◽  
N. Levin ◽  
A. Sokolov ◽  
E. Kamolins
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Direct Action ◽  
High Energy ◽  
Electrical Machine ◽  
Maintenance Costs ◽  
Wind Generators ◽  
Efficiency Estimation ◽  
Indirect Action ◽  
Proper Orientation

Abstract Application of wind generators opens wide possibilities for raising the efficiency of low- and medium-power wind generators (WGs). The mass of generators in the proposed version is smaller, their reliability higher, while maintenance costs are lower. At the same time, the use of high-energy permanent magnets in generators of enhanced power comes up against some obstacles, which can be overcome through proper orientation of magnetization at creation of a magnetic field in the airgap of electrical machine. In this regard, it might be preferable to use magnets with indirect action on the airgap instead of those with direct action. A convincing example of the former variant is a generator with tangentially oriented magnetization of permanent magnets. In the work, an attempt is done to prove the advantages of such installation in modern low- and medium-power WGs

k-Efficient domination: Algorithmic perspective

2022 ◽  
Author(s):  
Mohsen Alambardar Meybodi
Keyword(s):  
Decision Problem ◽  
Dominating Set ◽  
Polynomial Time Algorithm ◽  
Time Algorithm ◽  
Chordal Graphs ◽  
Sparse Graphs ◽  
Fpt Algorithm ◽  
Domination Problem ◽  
Efficient Dominating Set ◽  
Np Complete

A set [Formula: see text] of a graph [Formula: see text] is called an efficient dominating set of [Formula: see text] if every vertex [Formula: see text] has exactly one neighbor in [Formula: see text], in other words, the vertex set [Formula: see text] is partitioned to some circles with radius one such that the vertices in [Formula: see text] are the centers of partitions. A generalization of this concept, introduced by Chellali et al. [k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122], is called [Formula: see text]-efficient dominating set that briefly partitions the vertices of graph with different radiuses. It leads to a partition set [Formula: see text] such that each [Formula: see text] consists a center vertex [Formula: see text] and all the vertices in distance [Formula: see text], where [Formula: see text]. In other words, there exist the dominators with various dominating powers. The problem of finding minimum set [Formula: see text] is called the minimum [Formula: see text]-efficient domination problem. Given a positive integer [Formula: see text] and a graph [Formula: see text], the [Formula: see text]-efficient Domination Decision problem is to decide whether [Formula: see text] has a [Formula: see text]-efficient dominating set of cardinality at most [Formula: see text]. The [Formula: see text]-efficient Domination Decision problem is known to be NP-complete even for bipartite graphs [M. Chellali, T. W. Haynes and S. Hedetniemi, k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122]. Clearly, every graph has a [Formula: see text]-efficient dominating set but it is not correct for efficient dominating set. In this paper, we study the following: [Formula: see text]-efficient domination problem set is NP-complete even in chordal graphs. A polynomial-time algorithm for [Formula: see text]-efficient domination in trees. [Formula: see text]-efficient domination on sparse graphs from the parametrized complexity perspective. In particular, we show that it is [Formula: see text]-hard on d-degenerate graphs while the original dominating set has Fixed Parameter Tractable (FPT) algorithm on d-degenerate graphs. [Formula: see text]-efficient domination on nowhere-dense graphs is FPT.

Predicting value of prehospital body temperature for ICU admission of septic shock patients

2019 ◽  
Vol 18 (1) ◽  
pp. 56-58
Author(s):  
Romain Jouffroy ◽  
◽  
Anastasia Saade ◽  
Stephane Durand ◽  
Pascal Philippe ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Septic Shock ◽  
Body Temperature ◽  
Propensity Score Analysis ◽  
Call Centre ◽  
Icu Patients ◽  
Icu Admission ◽  
Score Analysis ◽  
The Mean ◽  
Proper Orientation

To specify whether an association exists between pre-hospital body temperature collected by the emergency medical services (EMS) call centre, and intensive care unit (ICU) admission of patients with septic shock. An observational study based on data collected by the EMS of Paris. All septic shocks were included. Among, the 140 calls concerning septic shock, 22 patients (16%) were admitted to ICU. The mean core temperature was 37.4±1.6°C for ICU and 38.6±1.1°C (p<4.10^-5) for non-ICU patients. Using propensity score analysis, the relative risk for ICU admission of patients with pre-hospital fever or hypothermia was 0.31 and 2 respectively. The study highlights the potential usefulness of early temperature measurement in septic shock patients to allow early proper orientation.

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