On the Stability of Continuous-Time Systems With Stochastic Delay: Applications to Gene Regulatory Circuits

2014 ◽  
Author(s):  
Mehdi Sadeghpour ◽  
Gábor Orosz
Keyword(s):  
Continuous Time ◽  
Regulatory Gene ◽  
Deterministic System ◽  
Average Delay ◽  
Stochastic Delay ◽  
Regulatory Circuits ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Gene Regulatory Circuits ◽  
Time Systems

In this paper the dynamics and stability of a linear system with stochastic delay are investigated. We assume that the delay may take finitely many different values and its dynamics are modeled by a continuous-time Markov chain. Semi-discretization is used to derive the dynamics of the second moment which leads to necessary and sufficient stability conditions for the trivial solution. We apply these results to investigate the stability of the steady state of an auto-regulatory gene-protein network. We demonstrate that stochastic delay may stabilize the system when the corresponding deterministic system with average delay is unstable.

scholarly journals The Stability and Stabilization of Stochastic Delay-Time Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Gang Li ◽  
Ming Chen
Keyword(s):  
Time Delay ◽  
Sufficient Conditions ◽  
Lyapunov Equation ◽  
Delay System ◽  
Stochastic Delay ◽  
Stability And Stabilization ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Time Systems ◽  
Stochastic Time

The aim of this paper is to investigate the stability and the stabilizability of stochastic time-delay deference system. To do this, we use mainly two methods to give a list of the necessary and sufficient conditions for the stability and stabilizability of the stochastic time-delay deference system. One way is in term of the operator spectrum andH-representation; the other is by Lyapunov equation approach. In addition, we introduce the notion of unremovable spectrum of stochastic time-delay deference system, describe the PBH criterion of the unremovable spectrum of time-delay system, and investigate the relation between the unremovable spectrum and the stabilizability of stochastic time-delay deference system.

scholarly journals Stability and Instability in the Lysogenic State of Phage Lambda

2010 ◽  
Vol 192 (22) ◽  
pp. 6064-6076 ◽  
Author(s):  
John W. Little ◽  
Christine B. Michalowski
Keyword(s):  
Intrinsic Rate ◽  
Growth Conditions ◽  
Emergent Properties ◽  
Regulatory Circuits ◽  
Stability And Instability ◽  
Natural Range ◽  
Analysis Of Stability ◽  
Stable Association ◽  
The Stability ◽  
Gene Regulatory Circuits

ABSTRACT Complex gene regulatory circuits exhibit emergent properties that are difficult to predict from the behavior of the components. One such property is the stability of regulatory states. Here we analyze the stability of the lysogenic state of phage λ. In this state, the virus maintains a stable association with the host, and the lytic functions of the virus are repressed by the viral CI repressor. This state readily switches to the lytic pathway when the host SOS system is induced. A low level of SOS-dependent switching occurs without an overt stimulus. We found that the intrinsic rate of switching to the lytic pathway, measured in a host lacking the SOS response, was almost undetectably low, probably less than 10−8/generation. We surmise that this low rate has not been selected directly during evolution but results from optimizing the rate of switching in a wild-type host over the natural range of SOS-inducing conditions. We also analyzed a mutant, λprm240, in which the promoter controlling CI expression was weakened, rendering lysogens unstable. Strikingly, the intrinsic stability of λprm240 lysogens depended markedly on the growth conditions; lysogens grown in minimal medium were nearly stable but switched at high rates when grown in rich medium. These effects on stability likely reflect corresponding effects on the strength of the prm240 promoter, measured in an uncoupled assay system. Several derivatives of λprm240 with altered stabilities were characterized. This mutant and its derivatives afford a model system for further analysis of stability.

scholarly journals Absolute stability of a class of fractional positive nonlinear systems

2019 ◽  
Vol 29 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Tadeusz Kaczorek
Keyword(s):  
Nonlinear Systems ◽  
Discrete Time ◽  
Continuous Time ◽  
Absolute Stability ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Discrete Time Systems ◽  
The Absolute ◽  
Necessary And Sufficient ◽  
Time Systems

Abstract The positivity and absolute stability of a class of fractional nonlinear continuous-time and discrete-time systems are addressed. Necessary and sufficient conditions for the positivity of this class of nonlinear systems are established. Sufficient conditions for the absolute stability of this class of fractional positive nonlinear systems are also given.

scholarly journals Entwurf von zeitkontinuierlichen ΣΔ-Modulatoren – Äquivalenz zwischen zeitkontinuierlichen und zeitdiskreten Systemen

2007 ◽  
Vol 5 ◽  
pp. 221-224
Author(s):  
J. Anders ◽  
W. Mathis ◽  
M. Ortmanns
Keyword(s):  
Stability Analysis ◽  
Discrete Time ◽  
Input Signal ◽  
Continuous Time ◽  
Wird Eine ◽  
Loop Delay ◽  
Discrete Time Systems ◽  
Excess Loop Delay ◽  
The Stability ◽  
Time Systems

Abstract. Im vorliegenden Artikel wird eine vollstängige, d.h. unter Einbeziehung des Eingangssignals, Äquivalenz zwischen zeitkontinuierlichen und zeitdiskreten ΣΔ-Modulatoren im Zustandsraum hergeleitet. Es wird ebenfalls gezeigt, wie eine wichtige Nichtidealität, das sog. "excess loop delay", in den Berechnungen berücksichtigt werden kann. Die dargestellte Methode dient dazu, den Entwurf und dabei vor allem die Stabilitätsuntersuchungen, von zeitkontinuierlichen ΣΔs auf die bereits empirisch intensiv erforschten zeitdiskreten Systeme zurückzuführen. In the article at hand a complete equivalency, i.e. including the input signal, between continuous-time and discrete-time ΣΔ-modulators in state-space is derived. In addition, it is shown, how one can incorporate the important non-ideality of "excess loop delay" into the formalism. The method introduced is supposed to facilitate the design, especially the stability analysis part of the design, of continuous-time ΣΔs by making use of the empirically thoroughly examined discrete-time systems.

scholarly journals Analysis of Positive Linear Continuous–Time Systems Using the Conformable Derivative

2018 ◽  
Vol 28 (2) ◽  
pp. 335-340 ◽  
Author(s):  
Tadeusz Kaczorek
Keyword(s):  
Asymptotic Stability ◽  
Linear System ◽  
Linear Systems ◽  
Continuous Time ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Conformable Derivative ◽  
Continuous Time Systems ◽  
Necessary And Sufficient ◽  
Time Systems

Abstract Positive linear continuous-time systems are analyzed via conformable fractional calculus. A solution to a fractional linear system is derived. Necessary and sufficient conditions for the positivity of linear systems are established. Necessary and sufficient conditions for the asymptotic stability of positive linear systems are also given. The solutions of positive fractional linear systems based on the Caputo and conformable definitions are compared.

scholarly journals Generalized convergence analysis of the fractional order systems

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 404-411
Author(s):  
Ahmad Ruzitalab ◽  
Mohammad Hadi Farahi ◽  
Gholamhossien Erjaee
Keyword(s):  
Fractional Order ◽  
Fractional Order Systems ◽  
Necessary And Sufficient Condition ◽  
Lyapunov Matrix Equation ◽  
Discrete Time Systems ◽  
Lyapunov Matrix ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Contraction Theory ◽  
Time Systems

Abstract The aim of the present work is to generalize the contraction theory for the analysis of the convergence of fractional order systems for both continuous-time and discrete-time systems. Contraction theory is a methodology for assessing the stability of trajectories of a dynamical system with respect to one another. The result of this study is a generalization of the Lyapunov matrix equation and linear eigenvalue analysis. The proposed approach gives a necessary and sufficient condition for exponential and global convergence of nonlinear fractional order systems. The examples elucidate that the theory is very straightforward and exact.

scholarly journals Stability of fractional positive nonlinear systems

2015 ◽  
Vol 25 (4) ◽  
pp. 491-496 ◽  
Author(s):  
Tadeusz Kaczorek
Keyword(s):  
Nonlinear Systems ◽  
Continuous Time ◽  
Lyapunov Method ◽  
Linear Part ◽  
Stability Conditions ◽  
Continuous Time Systems ◽  
Nonlinear Vector ◽  
The Stability ◽  
Metzler Matrix ◽  
Time Systems

AbstractThe conditions for positivity and stability of a class of fractional nonlinear continuous-time systems are established. It is assumed that the nonlinear vector function is continuous, satisfies the Lipschitz condition and the linear part is described by a Metzler matrix. The stability conditions are established by the use of an extension of the Lyapunov method to fractional positive nonlinear systems.

scholarly journals Computation of positive realizations for descriptor linear continuous-time systems

2018 ◽  
Vol 19 (12) ◽  
pp. 428-432
Author(s):  
Tadeusz Kaczorek
Keyword(s):  
Linear Systems ◽  
Continuous Time ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
New Method ◽  
Transfer Matrices ◽  
Continuous Time Systems ◽  
Necessary And Sufficient ◽  
Time Systems ◽  
Time Linear

A new method for computation of positive realizations of given transfer matrices of descriptor linear continuous-time linear systems is proposed. Necessary and sufficient conditions for the existence of positive realizations of transfer matrices are given. A procedure for computation of the positive realizations is proposed and illustrated by examples.

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