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Synchronization of chaotic Lur'e systems with delayed feedback control using deadzone nonlinearity

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Chinese Physics b 2011年第1期20卷 209-214页

作者： S.M.Lee o.M.kwon Ju H.Park Department of Electronic Engineering Daegu UniversityGyungsan 712-714Republic of Korea School of Electrical Engineering Chungbuk National University410 SungBong-RoHeungduk-guCheongju 361-763Republic of Korea Department of Electrical Engineering Yeungnam University214-1 Dae-DongKyongsan 712-749Republic of Korea

In this paper we present a synchronization method for chaotic Lur＇e systems by constructing a new piecewise Lyapunov function. Using a delayed feedback control scheme, a delay-dependent stability criterion is derived for the synchronization of chaotic systems that are represented by Lur＇e systems with deadzone nonlinearity. based on the Lyapunov-Krasovskii functional and by using some properties of the nonlinearity, a new delay-dependent stabilization condition for synchronization is obtained via linear matrix inequality （LMI） formulation. The criterion is less conservative than existing ones, and it will be verified through a numerical example.

关键词： Lur'e systems synchronization deadzone linear matrix inequality

A new approach to stability analysis of neural networks with time-varying delay via novel Lyapunov-Krasovskii functional

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Chinese Physics b 2010年第5期19卷 115-120页

作者： S.M.Lee o.M.kwon Ju H.Park Department of Electronic Engineering Daegu UniversityGyungsanGyungbuk 712-714Republic of Korea College of Electrical and Computer Engineering 410 SungBong-RoHeungduk-GuChungbuk National UniversityCheongju 361-763Republic of Korea Nonlinear Dynamics Group Department of Electrical EngineeringYeungnam University214-1 Dae-DongKyongsan 712-749Republic of Korea

In this paper, new delay-dependent stability criteria for asymptotic stability of neural networks with time-varying delays are derived. The stability conditions are represented in terms of linear matrix inequalities （LMIs） by constructing new Lyapunov-Krasovskii functional. The proposed functional has an augmented quadratic form with states as well as the nonlinear function to consider the sector and the slope constraints. The less conservativeness of the proposed stability criteria can be guaranteed by using convex properties of the nonlinear function which satisfies the sector and slope bound. Numerical examples are presented to show the effectiveness of the proposed method.

关键词： neural networks Lyapunov-Krasovskii functional sector bound time-delay

Maternal Group b Streptococcus Infection Correlates Inversely With Preeclampsia in Pregnant African American Women

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Maternal-Fetal Medicine 2024年第1期6卷 23-28页

作者： Keun Soo kwon Tzu Hsuan Cheng Simone A。Reynolds Jordan Zhou Huchong Cai Sharon Lee Ivan Velickovic Mudar Dalloul David Wlody Ming Zhang Department of Anesthesiology State University of New York-Downstate Health Sciences UniversityNew York 11203USA Department of Epidemiology and biostatistics School of Public HealthState University of New York-Downstate Health Sciences UniversityNew York 11203USA Department of obstetrics and Gynecology State University of New York-Downstate Health Sciences UniversityNew York 11203USA

objective:To determine whether an association exists between group b Streptococcus(GbS)colonization and preeclampsia among pregnant black ***:This retrospective cross-sectional study involved black women who gave birth at State University of New York Downstate Hospital between January 2010 and December *** were collected from the obstetric Department,including delivery date,time,mode of delivery,age of the mother,weeks of gestation at delivery,and antepartum *** GbS test results were originally determined using the eSwab transport *** was defined based on the American College of obstetricians and Gynecologists criteria for the periods 2010–2012 and 2013–*** primary outcome was whether GbS was associated with the outcome of preeclampsia in the population of black ***,including smoking status,gestational age,parity,body mass index,maternal age,and presence of herpes simplex virus(HSV)and human immunodeficiency virus(HIV)were examined as potential ***-squared test and logistic regression model were used,presenting odds ratios with 95%confidence intervals(Pon Demand for Academics(SAS Institute,Inc.,NY).Results:Among the 8,019 black women included in this study,GbS-positive women(n=977)had a 53%reduction in the likelihood of being diagnosed with preeclampsia compared to GbS-negative women(adjusted odds ratio,0.47;95%confidence interval,0.32–0.70).We did not find evidence of differences in the distribution of smoking habits(P=0.783)or maternal age(P=0.107)between GbS-positive and GbS-negative ***,the GbS-positive women tended to be less likely to have a preterm delivery(9.62%(94/977)vs.24.24%(1707/7042),Po be nulliparous(33.37%(326/977)vs.37.87%(2667/7042),P=0.006),and less likely to be obese(51.38%(502/977)vs.55.30%(3894/7042),Pompared with GbS-negative *** contrast,GbS-positive women were more likely to have a comorbid infecti

关键词： Pregnancy outcome Preeclampsia GbS colonization African American Afro-Caribbean

The Effect of Non-equilibrium Condensation on the Drag Coefficient in a Transonic Airfoil Flow

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Journal of Thermal Science 2012年第6期21卷 518-524页

作者： I.W.Kim M.M.A.Alam S.J.Lee Y.D.kwon S.b.kwon School of Mechanical Engineering Kyungpook Nat.Uni.1370Sankyuk-dongDaegu 702-701Korea Dept.of Advanced & Control Eng.Saga Uni.Japan

In this study, a transonic flow past NACA0012 profile at angle of attack α=0^0 whose aspect ratio AR is 1.0 with non-equilibrium condensation is analyzed by numerical analysis using a TVD scheme and is investigated using an intermittent indraft type supersonic wind tunnel. Transonic flows of 0.78-0.90 in free stream Mach number with the variations of the stagnation relative humidity（φ0） are tested. For the same free stream Mach number, the increase in φ0 causes decrease in the drag coefficient of profile which is composed of the drag components of form, viscous and wave. In the case of the same Moo and To, for more than φ0=30%, despite the irreversibility of process in non-equilibrium condensation, the drag by shock wave decreases considerably with the increase of φ0. on the other hand, it shows that the effect of condensation on the drag coefficients of form and viscous is negligible. As an example, the decreasing rate in the drag coefficient of profile caused by the influence of non-equilibrium condensation for the case of M∞=0.9 and φ0 =50% amounts to 34%. Also, it were turned out that the size of supersonic bubble （that is, the maximum height of supersonic zone） and the deviation of pressure coefficient from the value for M=1 decrease with the increase of φ0 for the same M∞.

关键词： Non-equilibrium condensation Transonic Moist air Drag coefficient Pressure coefficient

A metabolite of the gut microbiota:a facilitator of chemotherapy efficacy in cancer

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Signal Transduction and Targeted Therapy 2023年第7期8卷 3189-3191页

作者： byungsuk kwon School of biological Sciences University of UlsanUlsanRepublic of Korea

A recent study has identified a surprising metabolic connection between the gut microbiota and intratumoral neutrophils that impairs the oxidative stress adaptation response to chemotherapy in pancreatic cancer.1 This finding suggests that a microbiota metabolite might be used as an additive in improving chemotherapeutic efficacy for cancer patients.

关键词： chemotherapy cancer additive

Prospect of developing Nd-Fe-b-type magnet with high electrical resistivity

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Rare Metals 2020年第1期39卷 2-12页

作者： Hae-Woong kwon Min-Seok Kang Department of Materials Science and Engineering Pukyong National UniversityBusan48547Republic of Korea

Nd-Fe-b-type magnet is exclusively used as a rotor magnet in the traction motor of hybrid electric vehicle(HEV)and electric vehicle(EV),but its overly high operating temperature is a lingering problem attached to the *** major cause of the high operating temperature is eddy current,which is readily generated in the highly conductive metallic magnet under alternating magnetic field from stator *** this article,temperature rise in the Nd-Fe-b-type magnet with varying electrical resistivity under alternating magnetic field is discussed with the intention of highlighting the importance of enhancing the electrical resistivity for reducing the operating temperature of the Nd-Fe-b-type rotor *** rise in the Nd-Fe-b-type magnet(dielectric salt-added die-upset magnet)with high electrical resistivity is noticeably lower compared to the magnet(commercial sintered rotor magnet)with lower electrical resistivity,substantiating the theory that enhancing the electrical resistivity in the rotor magnet is fairly effective for suppressing the over-rise of its operating temperature during ***-upset process is revealed to be particularly pertinent for the fabrication of highly dense salt-added magnet with high electrical resistivity.

关键词： Rare-earth magnet Nd-Fe-b-type magnet Rotor magnet operating temperature Eddy current Electrical resistivity

Leader-following consensus criteria for multi-agent systems with time-varying delays and switching interconnection topologies

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Chinese Physics b 2012年第11期21卷 144-153页

作者： M.J.Park o.M.kwon Ju H.Park S.M.Lee E.J.Cha School of Electrical Engineering Chungbuk National University Department of Electrical Engineering Yeungnam University School of Electronic Engineering Daegu University Department of biomedical Engineering School of MedicineChungbuk National University

We consider multi-agent systems with time-varying delays and switching interconnection topologies. by con- structing a suitable Lyapunov-Krasovskii functional and using the reciprocally convex approach, new delay-dependent consensus criteria for the systems are established in terms of linear matrix inequalities （LMIs）, which can be easily solved by using various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

关键词： consensus multi-agent systems time delay Lyapunov method

Synchronization criteria for coupled Hopfield neural networks with time-varying delays

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Chinese Physics b 2011年第11期20卷 140-150页

This paper proposes new delay-dependent synchronization criteria for coupled Hopfield neural networks with time-varying delays. by construction of a suitable Lyapunov Krasovskii＇s functional and use of Finsler＇s lemma, novel synchronization criteria for the networks are established in terms of linear matrix inequalities （LMIs） which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

关键词： Hopfield neural networks coupling delay synchronization Lyapunov method

on the Classification of Positive Quaternionic Khler Manifolds with b_4=1

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Acta Mathematica Sinica,English Series 2010年第5期26卷 875-884页

作者： Jin Hong KIM Hee kwon LEE Department of Mathematical Sciences Korea Advanced Institute of Science and Technology Guseong-dong

Let M be a positive quaternionic Kahler manifold of dimension 4m. We already showed that if the symmetry rank is greater than or equal to [m/2] ＋ 2 and the fourth betti number b4 is equal to one, then M is isometric to HPm. The goal of this paper is to report that we can improve the lower bound of the symmetry rank by one for higher even-dimensional positive quaternionic Kahler manifolds. Namely, it is shown in this paper that if the symmetry rank of M with b4（M） = 1 is greater than or equal to m/2 ＋ 1 for m ≥ 10, then M is isometric to HPm. one of the main strategies of this paper is to apply a more delicate argument of Frankel type to positive quaternionic Kahler manifolds with certain symmetry rank.

关键词： positive quaternionic Kahler symmetry