469 research outputs found
Using discrete-time hyperchaotic-based asymmetric encryption and decryption keys for secure signal transmission
In this paper, a framework for the synchronization of two non-identical discrete-time hyperchaotic systems, namely the 3D Baier-Klein and the 3D Hitzel-Zele maps, based on the use of hybrid output feedback concept and aggregation techniques, is employed to design a two-channel secure communication system. New sufficient conditions for synchronization are obtained by the use of Borne and Gentina practical criterion for stabilization study associated to the forced arrow form matrix for system description. The efficiency of the proposed approach to confidentially recover the transmitted message signal is shown via an application to the hyperchaotic Baier-Klein and Hitzel-Zele systems, considered as generators of asymmetric encryption and decryption keys
On the practical global uniform asymptotic stability of stochastic differential equations
The method of Lyapunov functions is one of the most effective ones for the
investigation of stability of dynamical systems, in particular, of stochastic
differential systems. The main purpose of the paper is the analysis of the
stability of stochastic differential equations by using Lyapunov functions when
the origin is not necessarily an equilibrium point. The global uniform
boundedness and the global practical uniform exponential stability of so-
lutions of stochastic differential equations based on Lyapunov techniques are
investigated. Furthermore, an example is given to illustrate the applicability
of the main result.Comment: To appear in Stochastic
Some Existence Results for a Paneitz Type Problem Via the Theory of Critical Points at Infinity
In this paper a fourth order equation involving critical growth is considered
under Navier boundary condition. We give some topological conditions on a given
function to ensure the existence of solutions. Our methods involve the study of
the critical points at infinity and their contribution to the topology of the
level sets of the associated Euler Lagrange functionalComment: 26 page
0106: Association of lipoproteina and cholesteryl ester transfer protein-TaqIB polymorphism in Tunisian type 2 diabetes
Lipoprotein (a) [Lp(a)] is a plasma lipoprotein consisting of a LDL-like particle with a molecule of apolipoprotein B100 covalently linked to a very large additional glycoprotein known as apolipoprotein(a). Elevated Lp(a) levels constitute an independent risk factor for cardiovascular disease in the general population. Several studies have examined the possibility that type 2 diabetes could influence Lp(a) concentrations. Cholesteryl ester transfer protein (CETP) plays a key role in lipoprotein metabolism, promoting the exchange of triglycerides (TGs) and cholesteryl esters (CEs) between lipoprotein particles. The CETP TaqIB polymorphism in type 2 diabetes may have an increased risk for coronary artery disease.The aim of the present study was to examine the effect of the genetic polymorphism TaqIB of the CETP on the Lp(a) concentrations and the risk of coronaropathy in a cohort of type 2 diabetes.Plasma Lp(a) levels are not significantly associated with CETP TaqIB polymorphism in type 2 diabetes: no significant difference in the plasma Lp (a) between the diabetics having the genotype B1B1 and those having the genotype B2 (365.8±259 vs. 317±250.1mg; p=0.20). For the diabetics with genotype B1B1, Lp (a) was correlated significantly with the LDL (n=90, r=0.32; p=0.002) and the apoB (n=90, r=0.24, p=0.01). The proportion of the diabetics having the allèle B2 and Lp (a) superior to 300mg/l, is clearly more important at those having coronaropathy (51.1 vs. 29.2%; odds ratio=2.53; p=0.03).Lp(a) levels is a risk factor for cardiovascular disease in type 2 diabetic patients. This atherogenic risk seems to depend on the genetic polymorphism TaqIB of the CETP
Coexistence of Synchronization and Anti-Synchronization for Chaotic Systems via Feedback Control
Impact of Virtual Reality on Modern Education
Virtual reality in education is at its center stage. For students to gain relevant skills there is a need to introduce a virtual world so that one can achieve the practical aspect needed in the workplace environment. Memorizing facts makes students bored; hence, the need for virtual reality that will help students gain expertise. The paper seeks to discuss the impact of virtual reality in modern education. To understand the effects of virtual reality in the education sector, the theoretical approach and quantitative research have been used. The results of the study show that virtual reality assists students with special education needs and ensure skills are obtained. Virtual reality improves student self-esteem
Growth conditions for the stability of a class of time-varying perturbed singular systems
summary:In this paper, we investigate the problem of stability of linear time-varying singular systems, which are transferable into a standard canonical form. Sufficient conditions on exponential stability and practical exponential stability of solutions of linear perturbed singular systems are obtained based on generalized Gronwall inequalities and Lyapunov techniques. Moreover, we study the problem of stability and stabilization for some classes of singular systems. Finally, we present a numerical example to validate the effectiveness of the abstract results of this paper
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