Journal of Complex Systems
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The latest articles from Hindawi Publishing Corporation
© 2015 , Hindawi Publishing Corporation . All rights reserved.

Use of False Nearest Neighbours for Selecting Variables and Embedding Parameters for State Space Reconstruction
Mon, 09 Mar 2015 07:08:36 +0000
http://www.hindawi.com/journals/jcs/2015/932750/
If data are generated by a system with a ddimensional attractor,
then Takens’ theorem guarantees that reconstruction that is diffeomorphic
to the original attractor can be built from the single time series
in dimensional phase space. However, under certain conditions,
reconstruction is possible even in a space of smaller dimension. This
topic is very important because the size of the reconstruction space
relates to the effectiveness of the whole subsequent analysis. In
this paper, the false nearest neighbour (FNN) methods are revisited
to estimate the optimum embedding parameters and the most appropriate
observables for state space reconstruction. A modification of the
false nearest neighbour method is introduced.
The findings contribute to evidence that the length of the embedding
time window (TW) is more important than the reconstruction delay time
and the embedding dimension (ED) separately. Moreover, if several
time series of the same system are observed, the choice of the one
that is used for the reconstruction could also be critical. The results
are demonstrated on two chaotic benchmark systems.
Anna Krakovská, Kristína Mezeiová, and Hana Budáčová
Copyright © 2015 Anna Krakovská et al. All rights reserved.

Some Fixed Point Theorems in Complex Valued bMetric Spaces
Mon, 26 Jan 2015 07:57:57 +0000
http://www.hindawi.com/journals/jcs/2015/832467/
Recently, Azam et al. introduced the notion of complex valued metric spaces and proved fixed point theorems under the contraction condition. Rao et al. introduced the notion of complex valued bmetric spaces. In this paper, we obtain some fixed point results for the mapping satisfying rational expressions in complex valued bmetric spaces. Also, an example is given to illustrate our obtained result.
A. K. Dubey, Rita Shukla, and R. P. Dubey
Copyright © 2015 A. K. Dubey et al. All rights reserved.

Studying the Relationship between SystemLevel and ComponentLevel Resilience
Thu, 08 Jan 2015 07:36:11 +0000
http://www.hindawi.com/journals/jcs/2015/875265/
The capacity to maintain stability in a system relies on the components which make up the system. This study explores the relationship between componentlevel resilience and systemlevel resilience with the aim of identifying policies which foster systemlevel resilience in situations where existing incentives might undermine it. We use an abstract model of interacting specialized resource users and producers which can be parameterized to represent specific real systems. We want to understand how features, such as stockpiles, influence system versus component resilience. Systems are subject to perturbations of varying intensity and frequency. For our study, we create a simplified economy in which an inventory carrying cost is imposed to incentivize smaller inventories and examine how components with varying inventory levels compete in environments subject to periods of resource scarcity. The results show that policies requiring larger inventories foster higher componentlevel resilience but do not foster higher systemlevel resilience. Inventory carrying costs reduce production efficiency as inventory sizes increase. JIT inventory strategies improve production efficiency but do not afford any buffer against future uncertainty of resource availability.
Michael D. Mitchell and Walter E. Beyeler
Copyright © 2015 Michael D. Mitchell and Walter E. Beyeler. All rights reserved.

Group Measures and Modeling for Social Networks
Tue, 30 Sep 2014 11:19:33 +0000
http://www.hindawi.com/journals/jcs/2014/354385/
Social network modeling is generally based on graph theory, which allows for study of dynamics and emerging phenomena. However, in terms of neighborhood, the graphs are not necessarily adapted to represent complex interactions, and the neighborhood of a group of vertices can be inferred from the neighborhoods of each vertex composing that group. In our study, we consider that a group has to be considered as a complex system where emerging phenomena can appear. In this paper, a formalism is proposed to resolve this problematic by modeling groups in social networks using pretopology as a generalization of the graph theory. After giving some definitions and examples of modeling, we show how some measures used in social network analysis (degree, betweenness, and closeness) can be also generalized to consider a group as a whole entity.
Vincent Levorato
Copyright © 2014 Vincent Levorato. All rights reserved.

Dynamic Cournot Duopoly Game with Delay
Thu, 19 Jun 2014 06:08:39 +0000
http://www.hindawi.com/journals/jcs/2014/384843/
The delay Cournot duopoly game is studied. Dynamical behaviors of the game are studied. Equilibrium points and their stability are studied. The results show that the delayed system has the same Nash equilibrium point and the delay can increase the local stability region.
A. A. Elsadany and A. E. Matouk
Copyright © 2014 A. A. Elsadany and A. E. Matouk. All rights reserved.

Conception of Biologic System: Basis Functional Elements and Metric Properties
Tue, 29 Apr 2014 14:21:00 +0000
http://www.hindawi.com/journals/jcs/2014/693938/
A notion of biologic system or just a system implies a functional wholeness of comprising system components. Positive and negative feedback are the examples of how the idea to unite anatomical elements in the whole functional structure was successfully used in practice to explain regulatory mechanisms in biology and medicine. There are numerous examples of functional and metabolic pathways which are not regulated by feedback loops and have a structure of reciprocal relationships. Expressed in the matrix form positive feedback, negative feedback, and reciprocal links represent three basis elements of a Lie algebra of a special linear group . It is proposed that the mathematical group structure can be realized through the three regulatory elements playing a role of a functional basis of biologic systems. The structure of the basis elements endows the space of biological variables with indefinite metric. Metric structure resembles Minkowski's spacetime (+, −, −) making the carrier spaces of biologic variables and the space of transformations inhomogeneous. It endows biologic systems with a rich functional structure, giving the regulatory elements special differentiating features to form steady autonomous subsystems reducible to onedimensional components.
Garri Davydyan
Copyright © 2014 Garri Davydyan. All rights reserved.

Complex Stochastic Boolean Systems: Comparing Bitstrings with the Same Hamming Weight
Mon, 24 Mar 2014 07:31:40 +0000
http://www.hindawi.com/journals/jcs/2014/428418/
A complex stochastic Boolean system (CSBS) is a complex system depending on an arbitrarily large number of random Boolean variables. CSBSs arise in many different areas of science and engineering. A proper mathematical model for the analysis of such systems is based on the intrinsic order: a partial order relation defined on the set of all binary tuples of 0s and 1s. The intrinsic order enables one to compare the occurrence probabilities of two given binary tuples with no need to compute them, simply looking at the relative positions of their 0s and 1s. Regarding the analysis of CSBSs, the intrinsic order reduces the complexity of the problem from exponential ( binary tuples) to linear ( Boolean variables). In this paper, using the intrinsic ordering, we compare the occurrence probabilities of any two binary tuples having the same number of 1bits (i.e., the same Hamming weight). Our results can be applied to any CSBS with mutually independent Boolean variables.
Luis González
Copyright © 2014 Luis González. All rights reserved.

A Small MorrisLecar Neuron Network Gets Close to Critical Only in the SmallWorld Regimen
Thu, 07 Nov 2013 08:57:16 +0000
http://www.hindawi.com/journals/jcs/2013/675818/
Spontaneous emergence of neuronal activity avalanches characterized by powerlaw distributions is known to occur in different types of nervous tissues suggesting that nervous systems may operate at a critical regime. Here, we explore the possible relation of this dynamical state with the underlying topology in a smallsize network of interconnected MorrisLecar neurons. Studying numerically different topological configurations, we find that, very close to the efficient smallworld situation, the system selforganizes near to a critical branching process with observable distributions in the proximity of a power law with exponents similar to those reported in the experimental literature. Therefore, we conclude that the observed scaling is intimately related only with the smallworld topology.
Juan Luis Cabrera, Johans Hoenicka, and Daniel Macedo
Copyright © 2013 Juan Luis Cabrera et al. All rights reserved.

Weakly Compatible Maps Using E.A. and (CLR) Properties in Complex Valued Metric Spaces
Wed, 30 Oct 2013 11:03:03 +0000
http://www.hindawi.com/journals/jcs/2013/939607/
We introduce the notion of complex valued metric spaces and prove common fixed point theorems for weakly compatible maps along with E.A. and (CLR) properties in complex valued metric spaces.
Balbir Singh, Vishal Gupta, and Sanjay Kumar
Copyright © 2013 Balbir Singh et al. All rights reserved.

Common Fixed Point Theorems for a Rational Inequality in Complex Valued Metric Spaces
Thu, 24 Oct 2013 15:09:33 +0000
http://www.hindawi.com/journals/jcs/2013/942058/
We prove a common fixed point theorem for a pair of mappings. Also, we prove a common fixed point theorem for pairs of selfmappings along with weakly commuting property.
Pankaj Kumar, Manoj Kumar, and Sanjay Kumar
Copyright © 2013 Pankaj Kumar et al. All rights reserved.

About Evaluation of Complex Dynamical Systems
Wed, 09 Oct 2013 10:55:19 +0000
http://www.hindawi.com/journals/jcs/2013/204304/
Methods are proposed for evaluation of complex dynamical systems, choice of their optimal operating modes, determination of optimal operating system out of given class of equivalent systems, system’s timeline behaviour analysis on the basis of versatile multicriteria, and multilevel analysis of behaviour of system's elements.
Dmytro Polishchuk and Olexandr Polishchuk
Copyright © 2013 Dmytro Polishchuk and Olexandr Polishchuk. All rights reserved.

Diffusion Models for Information Dissemination Dynamics in Wireless Complex Communication Networks
Wed, 04 Sep 2013 10:26:02 +0000
http://www.hindawi.com/journals/jcs/2013/972352/
Information dissemination has become one of the most important services of communication networks. Modeling the diffusion of information through such networks is crucial for our modern information societies. In this work, novel models, segregating between useful and malicious types of information, are introduced, in order to better study Information Dissemination Dynamics (IDD) in wireless complex communication networks, and eventually allow taking into account special network features in IDD. According to the proposed models, and inspired from epidemiology, we investigate the IDD in various complex network types through the use of the SusceptibleInfected (SI) paradigm for useful information dissemination and the SusceptibleInfectedSusceptible (SIS) paradigm for malicious information spreading. We provide analysis and simulation results for both types of diffused information, in order to identify performance and robustness potentials for each dissemination process with respect to the characteristics of the underlying complex networking infrastructures. We demonstrate that the proposed approach can generically characterize IDD in wireless complex networks and reveal salient features of dissemination dynamics in each network type, which could eventually aid in the design of more advanced, robust, and efficient networks and services.
ShinMing Cheng, Vasileios Karyotis, PinYu Chen, KwangCheng Chen, and Symeon Papavassiliou
Copyright © 2013 ShinMing Cheng et al. All rights reserved.

Synchronization of Nonidentical Coupled Phase Oscillators in the Presence of Time Delay and Noise
Sun, 01 Sep 2013 11:47:14 +0000
http://www.hindawi.com/journals/jcs/2013/591513/
We have studied in this paper the dynamics of globally coupled phase oscillators having the Lorentzian
frequency distribution with zero mean in the presence of both time delay and noise. Noise may
be Gaussian or nonGaussian in characteristics. In the limit of zero noise strength, we find that
the critical coupling strength (CCS) increases linearly as a function of time delay. Thus the role
of time delay in the dynamics for the deterministic system is qualitatively equivalent to the effect
of frequency fluctuations of the phase oscillators by additive white noise in absence of time delay.
But for the stochastic model, the critical coupling strength grows nonlinearly with the increase of
the time delay. The linear dependence of the critical coupling strength on the noise intensity also
changes to become nonlinear due to creation of additional phase difference among the oscillators
by the time delay. We find that the creation of phase difference plays an important role in the
dynamics of the system when the intrinsic correlation induced by the finite correlation time of the
noise is small. We also find that the critical coupling is higher for the nonGaussian noise compared
to the Gaussian one due to higher effective noise strength.
Somrita Ray, Monoj Kumar Sen, Alendu Baura, and Bidhan Chandra Bag
Copyright © 2013 Somrita Ray et al. All rights reserved.

Bluffing as a Rational Strategy in a Simple PokerLike Game Model
Tue, 04 Jun 2013 14:03:00 +0000
http://www.hindawi.com/journals/jcs/2013/390454/
We present a simple adaptive learning model of a pokerlike game, by means of which we show how a bluffing strategy emerges very naturally and can also be rational and evolutionarily stable. Despite their very simple learning algorithms, agents learn to bluff, and the most bluffing player is usually the winner.
Andrea Guazzini and Daniele Vilone
Copyright © 2013 Andrea Guazzini and Daniele Vilone. All rights reserved.