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Fuzzy sliding mode control design of Markovian jump systems with time-varying delay
Sakthivel, R.,Sakthivel, R.,Nithya, V.,Selvaraj, P.,Kwon, O.M. Elsevier 2018 Journal of the Franklin Institute Vol.355 No.14
<P><B>Abstract</B></P> <P>This paper studies the robust stochastic stabilization problem for a class of fuzzy Markovian jump systems with time-varying delay and external disturbances via sliding mode control scheme. Based on the equivalent-input-disturbance (EID) approach, an online disturbance estimator is implemented to reject the unknown disturbance effect on the considered system. Specifically, to obtain exact EID estimation Luenberger fuzzy state observer and a low-pass filter incorporated to the closed-loop system. Moreover, novel fuzzy EID-based sliding mode control law is constructed to ensure the stability of the closed-loop system with satisfactory disturbance rejection performance. By employing Lyapunov stability theory and some integral inequalities, a new set of delay-dependent robust stability conditions is derived in terms of linear matrix inequalities (LMIs). The resulting LMI is used to find the gains of the state-feedback controller and the state observer a for the resulting closed-loop system. At last, numerical simulations based on the single-link arm robot model are provided to illustrate the proposed design technique.</P>
Sakthivel, Rathinasamy,Sakthivel, Ramalingam,Kaviarasan, Boomipalagan,Wang, Chao,Ma, Yong-Ki Hindawi Limited 2018 Complexity Vol.2018 No.-
<P>The problem of robust nonfragile synchronization is investigated in this paper for a class of complex dynamical networks subject to semi-Markov jumping outer coupling, time-varying coupling delay, randomly occurring gain variation, and stochastic noise over a desired finite-time interval. In particular, the network topology is assumed to follow a semi-Markov process such that it may switch from one to another at different instants. In this paper, the random gain variation is represented by a stochastic variable that is assumed to satisfy the Bernoulli distribution with white sequences. Based on these hypotheses and the Lyapunov-Krasovskii stability theory, a new finite-time stochastic synchronization criterion is established for the considered network in terms of linear matrix inequalities. Moreover, the control design parameters that guarantee the required criterion are computed by solving a set of linear matrix inequality constraints. An illustrative example is finally given to show the effectiveness and advantages of the developed analytical results.</P>
On the approximate controllability of semilinear fractional differential systems
Sakthivel, R.,Ren, Yong,Mahmudov, N.I. Elsevier 2011 COMPUTERS & MATHEMATICS WITH APPLICATIONS - Vol.62 No.3
<P><B>Abstract</B></P><P>Fractional differential equations have wide applications in science and engineering. In this paper, we consider a class of control systems governed by the semilinear fractional differential equations in Hilbert spaces. By using the semigroup theory, the fractional power theory and fixed point strategy, a new set of sufficient conditions are formulated which guarantees the approximate controllability of semilinear fractional differential systems. The results are established under the assumption that the associated linear system is approximately controllable. Further, we extend the result to study the approximate controllability of fractional systems with nonlocal conditions. An example is provided to illustrate the application of the obtained theory.</P>
WAVEs: A Novel and Promising Weapon in the Cancer Therapy Tool Box
Sakthivel, K.M.,Prabhu, V. Vinod,Guruvayoorappan, C. Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5
The Wiskott-Aldrich Syndrome Protein family Verprolin - homologous proteins (WAVEs), encoded by a metastasis promoter gene, play considerable roles in adhesion of immune cells, cell proliferation, migration and destruction of foreign agents by reactive oxygen species. These diverse functions have lead to the hypothesis that WAVE proteins have multi-functional roles in regulating cancer invasiveness, metastasis, development of tumor vasculature and angiogenesis. Differentials in expression of WAVE proteins are associated with a number of neoplasms include colorectal cancer, hepatocellular cancer, lung squamous cell carcinoma, human breast adenocarcinoma and prostate cancer. In this review we attempt to unify our knowledge regarding WAVE proteins, focusing on their potentials as diagnostic markers and molecular targets for cancer therapy.
Sakthivel, Kunnathur Murugesan,Guruvayoorappan, Chandrasekaran Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6
The aim of the present investigation was to evaluate the effect of A ferruginea extract on Dalton's lymphoma ascites (DLA) induced tumours in BALB/c mice. Experimental animals received A ferruginea extract (10 mg/kg.b.wt) intraperitoneally for 14 consecutive days after DLA tumor challenge. Treatment with extract significantly increased the life span, total white blood cell (WBC) count and haemoglobin (Hb) content and decreased the level of serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (${\gamma}$-GT) and nitric oxide (NO) in DLA bearing ascites tumor models. In addition, administration of extract significantly decreased the tumour volume and body weight in a DLA bearing solid tumor model. The levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-${\alpha}$), interleukin-1 beta (IL-$1{\beta}$), interleukin-6 (IL-6) and granulocyte monocyte-colony stimulating factor (GM-CSF), as well as pro-angiogenic growth factors such as vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) were elevated in solid tumour controls, but significantly reduced by A ferruginea administration. On the other hand, the extract stimulated the production of interleukin-2 (IL-2) and interferon-gamma (IFN-${\gamma}$) in animals with DLA induced solid tumours. Increase in $CD4^+$ T-cell population suggested strong immunostimulant activity for this extract. GC/MS and LC/MS analysis showed quinone, quinoline, imidazolidine, pyrrolidine, cyclopentenone, thiazole, pyrazole, catechin and coumarin derivatives as major compounds present in the A ferruginea methanolic extract. Thus, the outcome of the present study suggests that A ferruginea extract has immunomodulatory and tumor inhibitory activities and has the potential to be developed as a natural anticancer agent.
New exponential stability criteria for stochastic BAM neural networks with impulses
Sakthivel, R,Samidurai, R,Anthoni, S M Royal Swedish Academy of Sciences 2010 Physica scripta Vol.82 No.4
<P>In this paper, we study the global exponential stability of time-delayed stochastic bidirectional associative memory neural networks with impulses and Markovian jumping parameters. A generalized activation function is considered, and traditional assumptions on the boundedness, monotony and differentiability of activation functions are removed. We obtain a new set of sufficient conditions in terms of linear matrix inequalities, which ensures the global exponential stability of the unique equilibrium point for stochastic BAM neural networks with impulses. The Lyapunov function method with the Itô differential rule is employed for achieving the required result. Moreover, a numerical example is provided to show that the proposed result improves the allowable upper bound of delays over some existing results in the literature.</P>
Sakthivel Gandhi,Swaminathan Sethuraman,Uma Maheswari Krishnan 한국고분자학회 2013 Macromolecular Research Vol.21 No.8
Biocompatible and biodegradable polyesters have immense potential in medical applications as drug delivery vehicles and tissue engineering scaffolds. In this study, we synthesized biodegradable aliphatic polyesters,namely poly(butylene pimelate) (PBPi), poly(butylene succinate) (PBSu), and poly(butylene sebacate) (PBSe), by the polycondensation of equimolar quantities of dicarboxylic acid and diol using mesoporous SBA-15 silica as heterogeneous catalyst. We then compared its performance with a conventional homogenous catalyst, SnCl2·2H2O, which did not form these polymers. The synthesized SBA-15 catalyst was characterized by electron microscopy, nitrogen adsorption-desorption isotherm and infrared spectroscopy. The synthesized polyesters were evaluated using infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, gel permeation chromatography, scanning electron microscopy and goniometry. The combined results demonstrate that the SBA-15 mesoporous catalyst formed higher molecular weight degradable polyesters in addition to higher yield and purity, thus confirming the superiority of the mesoporous silica catalyst for polymer formation.