Search results for "Systems Theory"

Sustained oscillations in the MAP kinase cascade.

2016

Abstract The MAP kinase cascade is a network of enzymatic reactions arranged in layers. In each layer occurs a multiple futile cycle of phosphorylations. The fully phosphorylated substrate then serves as an enzyme for the layer below. This paper focuses on the existence of parameters for which Hopf bifurcations occur and generate periodic orbits. Furthermore it is explained how geometric singular perturbation theory allows to generalize results from simple models to more complex ones.

Networks Describing Dynamical Systems

2018

Abstract We consider systems of ordinary differential equations that arise in the theory of gene regulatory networks. These systems can be of arbitrary size but of definite structure that depends on the choice of regulatory matrices. Attractors play the decisive role in behaviour of elements of such systems. We study the structure of simple attractors that consist of a number of critical points for several choices of regulatory matrices.

Corporate Governance Theories: From Micro Theories to National Systems Theories

2004

The objective of this article is to conduct a survey of the different corporate governance theories. In the first part, we present the micro theories by opposing the disciplinary view to the knowledge-based view. The second part deals with the macro or national systems theories. We separate the theories based on appropriation of the organizational rent from those attributing a dominant role to production. This survey highlights that the financial view of corporate governance is a very particular case and presents many limits.

Fuzzy Logic Based Mathematical Structures and Their Applications: Book of Abstracts, 16th of March 2023, Jelgavas street 3, Riga

2023

Deterministic chaos and the first positive Lyapunov exponent: a nonlinear analysis of the human electroencephalogram during sleep

1993

Under selected conditions, nonlinear dynamical systems, which can be described by deterministic models, are able to generate so-called deterministic chaos. In this case the dynamics show a sensitive dependence on initial conditions, which means that different states of a system, being arbitrarily close initially, will become macroscopically separated for sufficiently long times. In this sense, the unpredictability of the EEG might be a basic phenomenon of its chaotic character. Recent investigations of the dimensionality of EEG attractors in phase space have led to the assumption that the EEG can be regarded as a deterministic process which should not be mistaken for simple noise. The calcu…

Lag-specific transfer entropy as a tool to assess cardiovascular and cardiorespiratory information transfer

2014

In the study of interacting physiological systems, model-free tools for time series analysis are fundamental to provide a proper description of how the coupling among systems arises from the multiple involved regulatory mechanisms. This study presents an approach which evaluates direction, magnitude, and exact timing of the information transfer between two time series belonging to a multivariate dataset. The approach performs a decomposition of the well-known transfer entropy (TE) which achieves 1) identifying, according to a lag-specific information-theoretic formulation of the concept of Granger causality, the set of time lags associated with significant information transfer, and 2) assig…

Orthogonal functions analysis of singular systems with impulsive responses

1990

Presents a systematic study using piecewise-constant orthogonal functions for the analysis of impulsive responses of singular systems. Walsh and block-pulse functions solutions are examined.

O* - Dynamical Systems and * - Derivations of Unbounded Operator Algebras

1999

A spatial theory is developed for * - derivations of an algebra of unbounded operators, in terms of the concept of O*-dynamical systems. Three notions of spatiality emerge, depending on the nature of the corresponding generator. Special emphasis is put on O*-dynamical systems generated by one-parameter groups of *-automorphisms and their *-derivations.

Reduced complexity models in the identification of dynamical networks: Links with sparsification problems

2009

In many applicative scenarios it is important to derive information about the topology and the internal connections of more dynamical systems interacting together. Examples can be found in fields as diverse as Economics, Neuroscience and Biochemistry. The paper deals with the problem of deriving a descriptive model of a network, collecting the node outputs as time series with no use of a priori insight on the topology. We cast the problem as the optimization of a cost function operating a trade-off between accuracy and complexity in the final model. We address the problem of reducing the complexity by fixing a certain degree of sparsity, and trying to find the solution that “better” satisfi…

Mathematical Modeling, Analysis, and Advanced Control of Complex Dynamical Systems

2014

1 School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia 2 Department of Engineering, Faculty of Technology and Science, University of Agder, 4898 Grimstad, Norway 3 College of Automation, Chongqing University, Chongqing 400044, China 4 School of Control Science and Engineering, Shandong University, Jinan 250061, China 5 College of Automation, Harbin Engineering University, Harbin 150001, China