On Decay Centrality

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Nikolas Tsakas
Keyword(s):  
Numerical Simulations ◽  
Maximum Degree ◽  
High Probability ◽  
Sufficient Conditions ◽  
Optimal Choice ◽  
Simple Rule ◽  
Decay Parameter ◽  
Rule Of Thumb ◽  
Very High

AbstractWe establish a relationship between decay centrality and two widely used measures of centrality, namely degree and closeness. We show that for low values of the decay parameter the nodes with maximum decay centrality also have maximum degree, whereas for high values of the decay parameter they also maximize closeness. For intermediate values, we provide sufficient conditions that allow the comparison of decay centrality of different nodes and we show via numerical simulations that in the vast majority of networks, the nodes with maximum decay centrality are characterized by a threshold on the decay parameter below which they belong to the set of nodes with maximum degree and above which they belong to the set of nodes with maximum closeness. We also propose a simple rule of thumb that ensures a nearly optimal choice with very high probability.

Costs and Benefits of the Transition to Low-carbon Economyin Russia: Perspectives up to 2050

2014 ◽  
pp. 70-91 ◽  
Author(s):  
I. Bashmakov ◽  
A. Myshak
Keyword(s):  
Emission Reduction ◽  
High Probability ◽  
Ghg Emissions ◽  
Mitigation Measures ◽  
Low Carbon ◽  
Costs And Benefits ◽  
Ghg Emission ◽  
Research Groups ◽  
Emissions Mitigation ◽  
Very High

This paper investigates costs and benefits associated with low-carbon economic development pathways realization to the mid XXI century. 30 scenarios covering practically all “visions of the future” were developed by several research groups based on scenario assumptions agreed upon in advance. It is shown that with a very high probability Russian energy-related GHG emissions will reach the peak before 2050, which will be at least 11% below the 1990 emission level. The height of the peak depends on portfolio of GHG emissions mitigation measures. Efforts to keep 2050 GHG emissions 25-30% below the 1990 level bring no GDP losses. GDP impact of deep GHG emission reduction - by 50% of the 1990 level - varies from plus 4% to minus 9%. Finally, very deep GHG emission reduction - by 80% - may bring GDP losses of over 10%.

Dynamic behavior of a stochastic SIRS model with two viruses

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jiandong Zhao ◽  
Tonghua Zhang ◽  
Zhixia Han
Keyword(s):  
Growth Rate ◽  
Asymptotic Stability ◽  
Global Existence ◽  
Numerical Simulations ◽  
Positive Solution ◽  
Sufficient Conditions ◽  
Environmental Noise ◽  
Sirs Model ◽  
The Moment ◽  
Disease Free

AbstractTo study the effect of environmental noise on the spread of the disease, a stochastic Susceptible, Infective, Removed and Susceptible (SIRS) model with two viruses is introduced in this paper. Sufficient conditions for global existence of positive solution and stochastically asymptotic stability of disease-free equilibrium in the model are given. Then, it is shown that the positive solution is stochastically ultimately bounded and the moment average in time of the positive solution is bounded. Our results mean that the environmental noise suppresses the growth rate of the individuals and drives the disease to extinction under certain conditions. Finally, numerical simulations are given to illustrate our main results.

scholarly journals Detectable sensation of a stochastic smoking model

2020 ◽  
Vol 18 (1) ◽  
pp. 1045-1055
Author(s):  
Abdullah Alzahrani ◽  
Anwar Zeb
Keyword(s):  
Stochastic Model ◽  
Numerical Simulations ◽  
Sufficient Conditions

Abstract This paper is related to the stochastic smoking model for the purpose of creating the effects of smoking that are not observed in deterministic form. First, formulation of the stochastic model is presented. Then the sufficient conditions for extinction and persistence are determined. Furthermore, the threshold of the proposed stochastic model is discussed, when noises are small or large. Finally, the numerical simulations are shown graphically with the software MATLAB.

scholarly journals Low degree connectivity of ad-hoc networks via percolation

2010 ◽  
Vol 42 (02) ◽  
pp. 559-576
Author(s):  
Emilio De Santis ◽  
Fabrizio Grandoni ◽  
Alessandro Panconesi
Keyword(s):  
Ad Hoc Networks ◽  
Maximum Degree ◽  
High Probability ◽  
Ad Hoc ◽  
Classical Problem ◽  
Universal Constant ◽  
Giant Component ◽  
Second Phase ◽  
Connected Network ◽  
Hoc Networks

Consider the following classical problem in ad-hoc networks. Suppose that n devices are distributed uniformly at random in a given region. Each device is allowed to choose its own transmission radius, and two devices can communicate if and only if they are within the transmission radius of each other. The aim is to (quickly) establish a connected network of low average and maximum degree. In this paper we present the first efficient distributed protocols that, in poly-logarithmically many rounds and with high probability, set up a connected network with O(1) average degree and O(log n) maximum degree. Our algorithms are based on the following result, which is a nontrivial consequence of classical percolation theory. Suppose that each device sets up its transmission radius in order to reach the K closest devices. There exists a universal constant K (independent of n) such that, with high probability, there will be a unique giant component (i.e. a connected component of size Θ(n)). Furthermore, all remaining components will be of size O(log2 n). This leads to an efficient distributed probabilistic test for membership in the giant component, which can be used in a second phase to achieve full connectivity.

APPROXIMATING THE NEAREST NEIGHBOR INTERCHARGE DISTANCE FOR NON-UNIFORM-DEGREE EVOLUTIONARY TREES

2001 ◽  
Vol 12 (04) ◽  
pp. 533-550 ◽  
Author(s):  
WING-KAI HON ◽  
TAK-WAH LAM
Keyword(s):  
Approximation Algorithms ◽  
Maximum Degree ◽  
Nearest Neighbor ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Approximation Ratio ◽  
Evolutionary Trees ◽  
Weighted Trees ◽  
Np Complete ◽  
Necessary And Sufficient

The nearest neighbor interchange (nni) distance is a classical metric for measuring the distance (dissimilarity) between evolutionary trees. It has been known that computing the nni distance is NP-complete. Existing approximation algorithms can attain an approximation ratio log n for unweighted trees and 4 log n for weighted trees; yet these algorithms are limited to degree-3 trees. This paper extends the study of nni distance to trees with non-uniform degrees. We formulate the necessary and sufficient conditions for nni transformation and devise more topology-sensitive approximation algorithms to handle trees with non-uniform degrees. The approximation ratios are respectively [Formula: see text] and [Formula: see text] for unweighted and weighted trees, where d ≥ 4 is the maximum degree of the input trees.

scholarly journals Antibiotic-associated diarrhea in children: how to identify, what to do and how to treat?

2016 ◽  
Vol 1 (1) ◽  
pp. 78-89
Author(s):  
I. N. Zakharova ◽  
I. V. Berezhnaya ◽  
E. B. Mumladze
Keyword(s):  
High Risk ◽  
Antibiotic Therapy ◽  
Intestinal Microbiota ◽  
High Probability ◽  
Pseudomembranous Colitis ◽  
Inflammatory Diseases ◽  
Pediatric Practice ◽  
Antibiotic Associated Diarrhea ◽  
New Generation ◽  
Very High

Rational antibiotic therapy is one of the most important components in the treatment of children with various infectious and inflammatory diseases. However, wide and sometimes unjustified use of AB in pediatric practice often leads to the development of a variety of complications. Children receiveing AB, especially during the first 5 years of life, are at a very high risk of developing antibiotic-associated diarrhea (AAD) which manifests itself in three or more episodes of unformed stools for two or more consecutive days or for 8 weeks after withdrawal. The most relevant pathogen of AAD is C. difficile which, according to various data, causes from 10 to 25% of AAD cases and 90 to 100% of all cases of pseudomembranous colitis (PMC). Given the high probability of developing dangerous complications such as PMC, special attention should be paid to the prevention of the infection associated with C. difficile by reducing the frequency of uncontrolled and unjustified use of AB. A new generation of eco-antibiotics can be recommended which allow to maintain diversity of the intestinal microbiota and are less likely to cause complications.

DYNAMICS OF A PREY-DEPENDENT DIGESTIVE MODEL WITH STATE-DEPENDENT IMPULSIVE CONTROL

2012 ◽  
Vol 22 (04) ◽  
pp. 1250092 ◽  
Author(s):  
LINNING QIAN ◽  
QISHAO LU ◽  
JIARU BAI ◽  
ZHAOSHENG FENG
Keyword(s):  
Numerical Simulations ◽  
Analytical Method ◽  
Impulsive Control ◽  
Dynamical Behavior ◽  
Sufficient Conditions ◽  
Period Doubling ◽  
Lambert W Function ◽  
Impulsive Effect ◽  
State Dependent ◽  
Theoretical Results

In this paper, we study the dynamical behavior of a prey-dependent digestive model with a state-dependent impulsive effect. Using the Poincaré map and the Lambert W-function, we find the analytical expression of discrete mapping. Sufficient conditions are established for transcritical bifurcation and period-doubling bifurcation through an analytical method. Exact locations of these bifurcations are explored. Numerical simulations of an example are illustrated which agree well with our theoretical results.

CONTROL OF n-SCROLL CHUA'S CIRCUIT

2009 ◽  
Vol 19 (11) ◽  
pp. 3813-3822 ◽  
Author(s):  
ABDELKRIM BOUKABOU ◽  
BILEL SAYOUD ◽  
HAMZA BOUMAIZA ◽  
NOURA MANSOURI
Keyword(s):  
Numerical Simulations ◽  
Fixed Points ◽  
Periodic Orbits ◽  
Predictive Control ◽  
Control Method ◽  
Sufficient Conditions ◽  
Chua’S Circuit ◽  
Unstable Periodic Orbits ◽  
Chua's Circuit ◽  
Necessary And Sufficient

This paper addresses the control of unstable fixed points and unstable periodic orbits of the n-scroll Chua's circuit. In a first step, we give necessary and sufficient conditions for exponential stabilization of unstable fixed points by the proposed predictive control method. In addition, we show how a chaotic system with multiple unstable periodic orbits can be stabilized by taking the system dynamics from one UPO to another. Control performances of these approaches are demonstrated by numerical simulations.

Dynamics of an autonomous Gilpin–Ayala competition model with random perturbation

2021 ◽  
pp. 2050043
Author(s):  
Jing Fu ◽  
Qixing Han ◽  
Daqing Jiang ◽  
Yanyan Yang
Keyword(s):  
White Noise ◽  
Numerical Simulations ◽  
Positive Solution ◽  
Necessary Conditions ◽  
Random Perturbation ◽  
Sufficient Conditions ◽  
Competition Model ◽  
Interacting Species ◽  
Sufficient And Necessary Conditions ◽  
Global Positive Solution

This paper discusses the dynamics of a Gilpin–Ayala competition model of two interacting species perturbed by white noise. We obtain the existence of a unique global positive solution of the system and the solution is bounded in [Formula: see text]th moment. Then, we establish sufficient and necessary conditions for persistence and the existence of an ergodic stationary distribution of the model. We also establish sufficient conditions for extinction of the model. Moreover, numerical simulations are carried out for further support of present research.

scholarly journals Generalized Projective Synchronization for Different Hyperchaotic Dynamical Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
M. M. El-Dessoky ◽  
E. Saleh
Keyword(s):  
Dynamical Systems ◽  
Numerical Simulations ◽  
Lorenz System ◽  
Sufficient Conditions ◽  
Projective Synchronization ◽  
Hyperchaotic Lorenz System ◽  
Generalized Projective Synchronization ◽  
Hyperchaotic Systems

Projective synchronization and generalized projective synchronization have recently been observed in the coupled hyperchaotic systems. In this paper a generalized projective synchronization technique is applied in the hyperchaotic Lorenz system and the hyperchaotic Lü. The sufficient conditions for achieving projective synchronization of two different hyperchaotic systems are derived. Numerical simulations are used to verify the effectiveness of the proposed synchronization techniques.

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