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New results on stability criteria for neural networks with time-varying delays

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Chinese Physics B 2011年第5期20卷 163-173页

作者： O.M.kwon J.W.kwon s.h.Kim school of Electrical Engineering Chungbuk National University410 SungBong-RoHeungduk-guCheongju 361-763Republic of Korea Department of Computer Engineering Kyungwon UniversitySan 65Sujung-guSungnam 461-701Republic of Korea school of Integrated Technology College of EngineeringYonsei University50 Yonsei-RoSeodaemun-guSeoul 120-749Republic of Korea

In this paper, the problem of stability analysis for neural networks with time-varying delays is considered. By constructing a new augmented Lyapunov-Krasovskii＇s functional and some novel analysis techniques, improved delaydependent criteria for checking the stability of the neural networks are established. The proposed criteria are presented in terms of linear matrix inequalities （LMIs） which can be easily solved and checked by various convex optimization algorithms. Two numerical examples are included to show the superiority of our results.

关键词： neural networks time-varying delays stability Lyapunov method

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

4-1BB signaling beyond T cells

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Cellular & Molecular Immunology 2011年第4期8卷 281-284页

作者： Dass s Vinay Byoung s kwon section of Clinical Immunology Allergyand RheumatologyDepartment of MedicineTulane University Health Sciences CenterNew OrleansLAUSA Cell and Immunobiology and R&D Center for Cancer TherapeuticsNational Cancer CenterIlsanGyeonggi-DoKorea

Originally discovered as a T cell-activating molecule,4-1BB(CD137)is now also recognized as an activator of non-T cells,thus imparting a new dimension to its potential in vivo effects.4-1BB expression is seen on a variety of non-T cells including activated dendritic cells(DCs),monocytes,neutrophils,B cells and natural killer(NK)cells,and promotes their individual effector *** T cell-and non-T cell-activating ability of 4-1BB may be the basis of its powerful anti-cancer,anti-autoimmune and anti-viral *** we discuss the consequence and importance of 4-1BB signaling in non-T *** consider its effects on immune regulation,and the distinct and/or overlapping pathways involved in these responses,as well as possible therapeutic applications.

关键词： APC cytokines natural killer cells T cells 4-1BB

study of the Unsteady Condensation of Moist Air in shock Tube

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Journal of Thermal science 2004年第3期13卷 235-244页

作者： s.-C. BAEK s.-B. kwon h.-D. KIM T. sETOGUChI s. MATsUO Department of Mechanical Engineering Kyungpook National University 1370 Sankyuk-dong Daegu 702-701 Korea school of Mechanical Engineering Andong National University Songchun-dong Andong 760-749 Korea Department of Mechanical system Engineering Saga University 1 Honjo Saga 840-8502 Japan

The major flow physics of the unsteady condensation in the subsonic flows induced by the unsteady expansion waves in shock tube was studied in this paper. The unsteady condensation phenomenon was analyzed by using the two-dimensional, unsteady, Navier-stokes equations, which were fully coupled with a droplet growth equation. The third-order TVD MUsCL scheme was applied to solve the governing equation systems. The computational results were compared with the previous experimental data. The time-dependent behavior of unsteady condensation of moist air in shock tube was investigated in details. The results show that the major characteristics of the unsteady condensation phenomenon in shock tube are very different from those in the supersonic wind tunnels.

关键词： shock tube shock wave expansion wave unsteady flow compressible flow unsteady condensation

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

Low cycle fatigue properties and cyclic deformation behavior of as-extruded AZ31 magnesium alloy

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Transactions of Nonferrous Metals society of China 2010年第B07期20卷 533-539页

作者： s.kwon K.sONG K.s.shIN s.I.KWUN Department of Materials science and Engineering Korea University school of Materials science and Engineering Seoul National University

The low cycle fatigue(LCF)properties of as-extruded AZ31 Mg alloy were investigated under total strain amplitudes in the range of 0.4%-1.2%with strain rate of 1×10- 2s -*** to the twinning effect in compression during loading and the detwinning effect during unloading,the alloy showed an asymmetric hysteresis *** cyclic stress response exhibited cyclic hardening at high total strain *** cyclic deformation behaviors were discussed using the Coffin-Manson plot,which divided the plastic strain amplitudes into the tension side and the compression *** the LCF tests that were started from either tension or compression under a total strain amplitude of 1.0%,the interaction between the twinning effect and dislocation was *** twinning effect during the LCF test and the variation of the dislocation density were investigated using optical microscopy and transmission electron microscopy,respectively.

关键词： AZ31 magnesium alloy low cycle fatigue twinning dislocation

DNA polymorphisms and genetic relationship among populations of Acacia leucophloea using RAPD markers

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Journal of Forestry Research 2018年第4期29卷 1006-1013页

作者： V. N. Mutharaian R. Kamalakannan A. Mayavel s. Makesh s. h. kwon K.-s. Kang Department of Botany Bharathiar University Coimbatore 641 046 India Institute of Forest Genetics and Tree Breeding Coimbatore 641 002 India horticultural College and Research Institute Tamilnadu Agricultural University Coimbatore 641 003 India Department of Forest sciences Seoul National University Seoul 08826 Republic of Korea ENVIs Centre on Forest Genetic Resources & Tree Improvement IFGTB Coimbatore 641 002 India ITC R&D Centre Peenya Industrial Area I Phase Bangalore 560 058 India Research Institute of Agriculture and Life sciences Seoul National University Seoul 08826 Republic of Korea

RAPD （randomly amplified polymorphic DNA） markers were employed to characterize polymorphisms among 5 provenances of Acacia leucophloea and to detect genetic relatedness of the species with 6 other acacias （A. holosericea, A. auriculiformis, A. mangium, A. dealbata, A. ferruginea, and A. nilotica） widely grown in India. Of 194 markers scored for the provenances, 29.38% exhibited polymorphism. Also, 326 markers were generated among 7 species of Acacia, accounting for 55.82% of the polymorphisms. The fifteen 10-mer primers employed were capable of producing 1-8 polymorphic bands for the provenances, and 6-17 for all seven species of Acacia. The genetic similarity coefficient based on Jaccard＇ s coefficient revealed that provenances Thirumangalam and Dharmapuri were closely related. The dendrogram based on a sequential agglomerative hierarchical non-overlapping （sAhN） clustering analysis grouped 4 provenances of A. leucophloea （Dharapuram, Thirumangalam, Pudukottai and Dharmapuri） into one cluster and the other provenance, sendurai, into a separate cluster. The genetic similarity matrix for 7 Acacia species showed that A. nilotica and A. dealbata were distantly related, while A. holosericea and A. ferruginea were very closely related. Cluster analysis grouped the species of Acacias into 3 major groups of which A. dealbata alone formed a separate group. The RAPD markers generated 36 provenance-specific markers and 162 species-specific markers that could have strong applications for species identification and tree breeding programs for A. leucophloea and for other Acacia species included in this study.

关键词： Acacia leucophloea Provenances Acaciasp Genetic relatedness RAPD markers

Polymeric micelle nanocarriers in cancer research

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Frontiers of Chemical science and Engineering 2016年第3期10卷 348-359页

作者： Dae hwan shin Yu Tong Tam Glen s. kwon school of Pharmacy University of Wisconsin Madison WI 53705 USA

Amphiphilic block copolymers （ABCs） assem- ble into a spherical nanoscopic supramolecular core/shell nanostructure termed a polymeric micelle that has been widely researched as an injectable nanocarrier for poorly water-soluble anticancer agents. The aim of this review article is to update progress in the field of drug delivery towards clinical trials, highlighting advances in polymeric micelles used for drug solubilization, reduced off-target toxicity and tumor targeting by the enhanced permeability and retention （EPR） effect. Polymeric micelles vary in stability in blood and drug release rate, and accordingly play different but key roles in drug delivery. For intravenous （IV） infusion, polymeric micelles that disas- semble in blood and rapidly release poorly water-soluble anticancer agent such as paclitaxel have been used for drug solubilization, safety and the distinct possibility of toxicity reduction relative to existing solubilizing agents, e.g., Cremophor EL. stable polymeric micelles are long- circulating in blood and reduce distribution to non-target tissue, lowering off-target toxicity. Further, they participate in the EPR effect in murine tumor models. In summary, polymeric micelles act as injectable nanocarriers for poorly water-soluble anticancer agents, achieving reduced toxi- city and targeting tumors by the EPR effect.

关键词： nanomedicine parenteral poly(ethylene glycol) poly(lactic acid) reformulation