Perturbation of renewal processes

Perturbation of renewal processes

Date: May 2008
Creator: Akin, Osman Caglar
Description: Renewal theory began development in the early 1940s, as the need for it in the industrial engineering sub-discipline operations research had risen. In time, the theory found applications in many stochastic processes. In this thesis I investigated the effect of seasonal effects on Poisson and non-Poisson renewal processes in the form of perturbations. It was determined that the statistical analysis methods developed at UNT Center for Nonlinear Science can be used to detect the effects of seasonality on the data obtained from Poisson/non-Poisson renewal systems. It is proved that a perturbed Poisson process can serve as a paradigmatic model for a case where seasonality is correlated to the noise and that diffusion entropy method can be utilized in revealing this relation. A renewal model making a connection with the stochastic resonance phenomena is used to analyze a previous neurological experiment, and it was shown that under the effect of a nonlinear perturbation, a non-Poisson system statistics may make a transition and end up in the of Poisson basin of statistics. I determine that nonlinear perturbation of the power index for a complex system will lead to a change in the complexity characteristics of the system, i.e., the system will reach ...
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A Dynamic and Thermodynamic Approach to Complexity.

A Dynamic and Thermodynamic Approach to Complexity.

Date: August 2003
Creator: Yang, Jin
Description: The problem of establishing the correct approach to complexity is a very hot and crucial issue to which this dissertation gives some contributions. This dissertation considers two main possibilities, one, advocated by Tsallis and co-workers, setting the foundation of complexity on a generalized, non-extensive , form of thermodynamics, and another, proposed by the UNT Center for Nonlinear Science, on complexity as a new condition that, for physical systems, would be equivalent to a state of matter intermediate between dynamics and thermodynamics. In the first part of this dissertation, the concept of Kolmogorov-Sinai entropy is introduced. The Pesin theorem is generalized in the formalism of Tsallis non-extensive thermodynamics. This generalized form of Pesin theorem is used in the study of two major classes of problems, whose prototypes are given by the Manneville and the logistic map respectively. The results of these studies convince us that the approach to complexity must be made along lines different from those of the non-extensive thermodynamics. We have been convinced that the Lévy walk can be used as a prototype model of complexity, as a condition of balance between order and randomness that yields new phenomena such as aging, and multifractality. We reach the conclusions that ...
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Site correlation, anomalous diffusion, and enhancement of the localization length

Site correlation, anomalous diffusion, and enhancement of the localization length

Date: November 1, 1996
Creator: Allegrini, Paolo; Bonci, Luca; Grigolini, Paolo & West, Bruce J.
Description: This article discusses site correlation, anomalous diffusion, and enhancement of localization length.
Contributing Partner: UNT College of Arts and Sciences
Reply to the Comment  "Intercluster correlation in Seismicity" by Helmstetter and Sornette

Reply to the Comment "Intercluster correlation in Seismicity" by Helmstetter and Sornette

Date: September 15, 2003
Creator: Mega, Mirko S.; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Palatella, Luigi; Rapisarda, Andrea et al.
Description: This paper is a reply to the comment by Helmstetter and Sornette titled "Intercluster correlation in Seismicity" which addresses an important point in a paper written by the authors that needs to be clarified.
Contributing Partner: UNT College of Arts and Sciences
Mega et al. Reply

Mega et al. Reply

Date: March 26, 2004
Creator: Mega, Mirko S.; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Palatella, Luigi; Rapisarda, Andrea et al.
Description: This article is a reply to a comment by A. Helmstetter and D. Sornette about the article 'Power-Law Time Distribution of Large Earthquakes' from 2003.
Contributing Partner: UNT College of Arts and Sciences
Scaling Breakdown: A Signature of Aging

Scaling Breakdown: A Signature of Aging

Date: July 12, 2002
Creator: Allegrini, Paolo; Bellazzini, Jacopo; Bramanti, G.; Ignaccolo, Massimiliano; Grigolini, Paolo & Yang, J.
Description: In this article, the authors prove that the Lévy walk is characterized by bilinear scaling. This effect mirrors the existence of a form of aging that does not require the adoption of nonstationary conditions.
Contributing Partner: UNT College of Arts and Sciences
Long- and Short-Time Analysis of Heartbeat Sequences: Correlation with Mortality Risk in Congestive Heart Failure Patients

Long- and Short-Time Analysis of Heartbeat Sequences: Correlation with Mortality Risk in Congestive Heart Failure Patients

Date: 2003
Creator: Allegrini, Paolo; Balocchi, Rita; Chillemi, Santi; Grigolini, Paolo; Hamilton, P.; Maestri, Roberto et al.
Description: Article discussing long- and short-time analysis of heartbeat sequences and the correlation with mortality risk in congestive heart failure patients.
Contributing Partner: UNT College of Arts and Sciences
Real event detection and the treatment of congestive heart failure: an efficient technique to help cardiologists to make crucial decisions

Real event detection and the treatment of congestive heart failure: an efficient technique to help cardiologists to make crucial decisions

Date: September 2002
Creator: Allegrini, Paolo; Balocchi, Rita; Chillemi, Santi; Grigolini, Paolo; Hamilton, P.; Maestri, Roberto et al.
Description: Paper discussing the treatment of congestive heart failure. Abstract: Using a method of entropic analysis of time series we establish the correlation between heartbeat long-range memory and mortality risk in patients with congestive heart failure.
Contributing Partner: UNT College of Arts and Sciences
Networking of psychophysics, psychology, and neurophysiology

Networking of psychophysics, psychology, and neurophysiology

Date: November 5, 2012
Creator: West, Bruce J. & Grigolini, Paolo
Description: Article discussing the dynamic networking and dynamic networks in complex research on psychophysics, psychology, and neurophysiology.
Contributing Partner: UNT College of Arts and Sciences
Scaling in Non-stationary Time Series 2: Teen Birth Phenomenon

Scaling in Non-stationary Time Series 2: Teen Birth Phenomenon

Date: February 2, 2008
Creator: Ignaccolo, Massimiliano; Allegrini, Paolo; Grigolini, Paolo; Hamilton, P. & West, Bruce J.
Description: This paper is devoted to the problem of statistical mechanics raised by the analysis of an issue of sociological interest: the teen birth phenomenon.
Contributing Partner: UNT College of Arts and Sciences
Non-Poisson distribution of the time distances between two consecutive clusters of earthquakes

Non-Poisson distribution of the time distances between two consecutive clusters of earthquakes

Date: 2004
Creator: Palatella, Luigi; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Mega, Mirko S.; Rapisarda, Andrea et al.
Description: Article discussing non-Poisson distribution of the time distances between two consecutive clusters of earthquakes.
Contributing Partner: UNT College of Arts and Sciences
Stromatolites: why do we care?

Stromatolites: why do we care?

Date: April 2004
Creator: Ignaccolo, Massimiliano; Schwettmann, Arne; Failla, Roberto; Storrie-Lombardi, Michael C. & Grigolini, Paolo
Description: Article discussing stromatolites. The authors apply the method of Diffusion Entropy (DE) to the study of stromatolites by means of a two-dimensional procedure that makes it possible for us to compare the DE analysis to the results of a compression method.
Contributing Partner: UNT College of Arts and Sciences
Fingering Instabilities, Collapse, Avalanches and Self-Organized Criticality in Liquid Foams

Fingering Instabilities, Collapse, Avalanches and Self-Organized Criticality in Liquid Foams

Date: November 29, 2002
Creator: Glazier, J. A.
Description: Foam is solid-like under low stress and liquid-like under high stress. It can sustain a small load elastically but a large one causes it to flow indefinitely. When shear stress is present, a pair of adjacent bubbles can be squeezed apart by another pair, leading to a T1 switching event. This local but abrupt topological change results in bubble-complexes rearranging from one metastable configuration to another. The resulting macroscopic dynamics is highly nonlinear and complex, involving large local motion that depends on correlations between nearby bubbles. The main goal of this study was to find the connection between the behavior of individual membranes and the whole network and to relate local rearrangements to global rheological properties of flowing foams.
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Memory Beyond Memory in Heart Beating, a Sign of a Healthy Physiological Condition

Memory Beyond Memory in Heart Beating, a Sign of a Healthy Physiological Condition

Date: April 11, 2002
Creator: Allegrini, Paolo; Grigolini, Paolo; Hamilton, P.; Palatella, Luigi & Raffaelli, G.
Description: In this article, the authors describe two types of memory and illustrate each using artificial and actual heartbeat data sets.
Contributing Partner: UNT College of Arts and Sciences
Towards the timely detection of toxicants

Towards the timely detection of toxicants

Date: April 2004
Creator: Ignaccolo, Massimiliano; Grigolini, Paolo & Gross, Guenter W.
Description: Article discussing the problem of enhancing the sensitivity of biosensors to the influence of toxicants, with an entropy method of analysis, denoted as CASSANDRA, for the specific purpose of studying non-stationary time series.
Contributing Partner: UNT College of Arts and Sciences
Memory Effects in Fractional Brownian Motion with Hurst Exponent H<1/3

Memory Effects in Fractional Brownian Motion with Hurst Exponent H<1/3

Date: August 27, 2010
Creator: Bologna, Mauro; Vanni, Fabio; Krokhin, Arkadii A. & Grigolini, Paolo
Description: This article discusses a study on the regression to the origin of a walker driven by dynamically generated fractional Brownian motion.
Contributing Partner: UNT College of Arts and Sciences
A fluctuating environment as a source of periodic modulation

A fluctuating environment as a source of periodic modulation

Date: March 2007
Creator: Bianco, Simone; Grigolini, Paolo & Paradisi, Paolo
Description: Article discussing a fluctuating environment as a source of periodic modulation.
Contributing Partner: UNT College of Arts and Sciences
Linear Response to Perturbation of Nonexponential Renewal Processes

Linear Response to Perturbation of Nonexponential Renewal Processes

Date: November 23, 2005
Creator: Barbi, Francesco; Bologna, Mauro & Grigolini, Paolo
Description: This article discusses the linear response to perturbation of nonexponential renewal processes.
Contributing Partner: UNT College of Arts and Sciences
Absorption and Emission in the Non-Poissonian Case

Absorption and Emission in the Non-Poissonian Case

Date: July 28, 2004
Creator: Aquino, Gerardo; Palatella, Luigi & Grigolini, Paolo
Description: Article on absorption and emission in the Non-Poissonian Case.
Contributing Partner: UNT College of Arts and Sciences
Random Growth of Interfaces as a Subordinated Process

Random Growth of Interfaces as a Subordinated Process

Date: July 30, 2004
Creator: Failla, Roberto; Grigolini, Paolo; Ignaccolo, Massimiliano & Schwettmann, Arne
Description: Article discussing the random growth of interfaces as a subordinated process.
Contributing Partner: UNT College of Arts and Sciences
Power-Law Time Distribution of Large Earthquakes

Power-Law Time Distribution of Large Earthquakes

Date: May 2003
Creator: Mega, Mirko S.; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Palatella, Luigi; Rapisarda, Andrea et al.
Description: Article discussing power-law time distribution of large earthquakes and a study of the statistical properties of time distribution of seismicity in California by means of diffusion entropy.
Contributing Partner: UNT College of Arts and Sciences
Non-extensive diffusion entropy analysis: non-stationarity in teen birth phenomena

Non-extensive diffusion entropy analysis: non-stationarity in teen birth phenomena

Date: February 6, 2008
Creator: Scafetta, Nicola; Grigolini, Paolo; Hamilton, P. & West, Bruce J.
Description: Paper discussing non-extensive diffusion entropy analysis and non-stationarity in teen birth phenomena.
Contributing Partner: UNT College of Arts and Sciences
Renewal Aging as Emerging Property of Phase Synchronization

Renewal Aging as Emerging Property of Phase Synchronization

Date: February 6, 2008
Creator: Bianco, Simone; Geneston, Elvis L.; Grigolini, Paolo & Ignaccolo, Massimiliano
Description: Paper discussing renewal aging as emerging property of phase synchronization.
Contributing Partner: UNT College of Arts and Sciences
Experimental Quenching of Harmonic Stimuli: Universality of Linear Response Theory

Experimental Quenching of Harmonic Stimuli: Universality of Linear Response Theory

Date: July 15, 2009
Creator: Allegrini, Paolo; Bologna, Mauro; Fronzoni, Leone; Grigolini, Paolo & Silvestri, Ludovico
Description: This article discusses experimental quenching of harmonic stimuli.
Contributing Partner: UNT College of Arts and Sciences
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