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EXPLICIT BOUNDS OF EIGENVALUES FOR STIFFNESS MATRICES BY QUADRATIC HIERARCHICAL BASIS METHOD)

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Journal of Computational Mathematics 2003年第2期21卷 113-124页

作者： sang dong kim Byeong Chun SHIN Department of Mathematics Kyungpook National UniversityTaegu 702-701KoreaDepartment of MathematicsChonnam National UniversityGwangju 500-757Korea

The bounds for the eigenvalues of the stiffness matrices in the finite element discretization corresponding to Lu := - u' with zero boundary conditions by quadratic hierarchical basis are shown explicitly. The condition number of the resulting system behaves like O(1/h) where h is the mesh size. We also analyze a main diagonal preconditioner of the stiffness matrix which reduces the condition number of the preconditioned system to O(1).

关键词： hierarchical basis multilevel

DISCRETE MINUS ONE NORM LEAST-SQUARES FOR THE STRESS FORMULATION OF LINEAR ELASTICITY WITH NUMERICAL RESULTS

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Journal of Computational Mathematics 2003年第6期21卷 689-702页

作者： sang dong kim Byeong Chun Shin Seokchan kim Gyungsoo Woo Department of Mathematics Kyungpook National University Taegu 702-701 KoreaDepartment of Mathematics Chonnam National University Kwangju 500-757 KoreaDepartment of Mathematics Changwon Nationnal University Changwon 641-773 KoreaDepartment of Mathematics Changwon Nationnal University Changwon 641-773 Korea

This paper studies the discrete minus one norm least-squares methods for the stress formulation of pure displacement linear elasticity in two dimensions. The proposed least-squares functional is defined as the sum of the L2- and H-1-norms of the residual equations weighted appropriately. The minus one norm in the functional is replaced by the discrete minus one norm and then the discrete minus one norm least-squares methods are analyzed with various numerical results focusing on the finite element accuracy and multigrid convergence performances.

关键词： H-1 least-squares Linear elasticity Multigrid method.

First-Order System Least-Squares Methods for a Flux Control Problem by the Stokes Flow

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Communications in Computational Physics 2010年第4期7卷 738-758页

作者： Soorok Ryu sang dong kim Hyung-Chun Lee Department of Industrial and Applied Mathematics Kyungpook National UniversityDaegu 702-701Korea Department of Mathematics Kyungpook National UniversityDaegu 702-701Korea Department of Mathematics Ajou UniversitySuwon 443-749Korea

This article deals with a first-order least-squares approach to the solution of an optimal control problem governed by Stokes *** with our earlier work on a velocity control by the Stokes flow in[***,H.-*** and ***,SIAM ***.,47(2009),pp.1524-1545],we recast the objective functional as a H1 seminorm in the velocity control *** introducing a velocity-flux variable and using the Lagrange multiplier rule,a first-order optimality system is *** show that the least-squares principle based on L2 norms applied to this system yields the optimal discretization error estimates for each variable in H1 norm,including the velocity *** numerical tests,multigrid method is employed to the discrete algebraic system,so that the velocity and flux controls are obtained.

关键词： Optimal control optimization least-squares finite element methods Lagrange multiplier Stokes equations.

Endovascular treatment for delayed type Ib endoleak with hostile arterial anatomy after endovascular abdominal aortic aneurysm repair

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Chinese Medical Journal 2022年第15期135卷 1876-1877页

作者： Jong Seok Lee sang dong kim Department of Surgery Division of Vascular and Transplant SurgeryCollege of MedicineThe Catholic University of KoreaSeoul 06591Korea

To the Editor:A 71-year-old male patient was referred for incidentally delayed type Ib_endoleak_on computed tomographic angiography(CTA).He had been performed endovascular abdominal aortic aneurysm repair(EVAR)with the Zenith(Cook Inc,Bloomington,IN,USA)stent-grafts for right common iliac artery(CIA)aneurysm with a diameter of 4.4 cm at 17 months ago.

关键词： anatomy aneurysm abdominal

Comparison of Minimal Skin Incision Technique in Living Kidney Transplantation and Conventional Kidney Transplantation

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Chinese Medical Journal 2016年第8期129卷 917-921页

作者： sang-dong kim Ji-II kim In-Sung Moon Sun-Cheol Park Department of Surgery Division of Vascular and Transplant Surgery College of Medicine The Catholic University of Korea Seoul 137-040 Korea

Background：Recently,the most common incision for kidney transplantation （KT） is an inverted J-shaped incision known as the ＆quot;hockey-stick.＆quot; However,demands for minimally invasive surgery in KT are increasing as in other various fields of ***,we evaluated whether there is difference between minimal skin incision technique in kidney transplantation （MIKT） and conventional KT （CKT）.Methods：Between June 2006 and March 2013,a total of 452 living kidney transplant patients were *** MIKT group included 17 young unmarried women whose body mass index was 〈25 kg/m^2 and had no anatomic *** CKT group included 435 *** MIKT operation technique restricted to the 10 cm-sized skin incision in the lower right abdomen from laterally below the anterior superior iliac spine to the midline just above the pubis was *** compared the baseline clinical characteristics and postoperative results between two *** proper comparison,propensity score matching was ***：There was no difference in graft function,survival,and postoperative complication rate between MIKT and CKT groups （all P 〉 0.05）.The 5-year graft survival was 92.3% and 85.7% in MIKT and CKT groups,respectively （P =0.786）.Conclusions：Our results indicated that MIKT showed more favorable cosmetic results,and there were no statistical differences in various postoperative factors including graft function,survival,and complications compared with ***,we suggested that MIKT is an appropriate method for selected patients in living KT.

关键词： Kidney Transplantation Minimal Skin Incision: Conventional Kidney Transplantation

Finite Difference Preconditioners for Legendre Based Spectral Element Methods on Elliptic Boundary Value Problems

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Applied Mathematics 2013年第5期4卷 838-847页

作者： Seonhee kim Amik St-Cyr sang dong kim Computation and Modeling Shell Technology Center Houston (STCH) Houston USA Department of Mathematics Kyungpook National University Daegu South Korea

Finite difference type preconditioners for spectral element discretizations based on Legendre-Gauss-Lobatto points are analyzed. The latter is employed for the approximation of uniformly elliptic partial differential problems. In this work, it is shown that the condition number of the resulting preconditioned system is bounded independently of both of the polynomial degrees used in the spectral element method and the element sizes. Several numerical tests verify the h-p independence of the proposed preconditioning.

关键词： Finite Difference Preconditioner Iterative Method Spectral Element Method Elliptic Operator

Dragonfly Interaction Algorithm for Optimization of Queuing Delay in Industrial Wireless Networks

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Journal of Bionic Engineering 2024年第1期21卷 447-485页

作者： Sanjay Bhardwaj Da-Hye kim dong-Seong kim Department of IT Convergence Engineering ICT Convergence Research CenterKumoh National Institute of TechnologyGumiSouth Korea

In industrial wireless networks,data transmitted from source to destination are highly *** often leads to the queuing of the data,and poor management of the queued data results in excessive delays,increased energy consumption,and packet ***,a nature-inspired-based Dragonfly Interaction Optimization Algorithm(DMOA)is proposed for optimization of the queue delay in industrial wireless *** term“interaction”herein used is the characterization of the“flying movement”of the dragonfly towards damselflies(female dragonflies)for *** a result,interaction is represented as the flow of transmitted data packets,or traffic,from the source to the base *** includes each and every feature of dragonfly movement as well as awareness of the rival dragonflies,predators,and damselflies for the desired optimization of the queue *** features are juxtaposed as noise and interference,which are further used in the calculation of industrial wireless metrics:latency,error rate(reliability),throughput,energy efficiency,and fairness for the optimization of the queue *** analysis,convergence analysis,the Wilcoxon test,the Friedman test,and the classical as well as the 2014 IEEE Congress of Evolutionary Computation(CEC)on the benchmark functions are also used for the evaluation of DMOA in terms of its robustness and *** results demonstrate the robustness of the proposed algorithm for both classical and benchmarking functions of the IEEE CEC ***,the accuracy and efficacy of DMOA were demonstrated by means of the convergence rate,Wilcoxon testing,and ***,fairness using Jain’s index in queue delay optimization in terms of throughput and latency,along with computational complexity,is also evaluated and compared with other *** results show that DMOA exceeds other bio-inspired optimization algorithms in terms of fairness in queue delay management and average packet *** proposed a

关键词： Dragonfly Damselfly Interaction Queuing delay Optimization Industrial wireless networks

Analysis of the Oscillatory Flows of Multiple Shock Waves in a Constant Area Duct

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Journal of Thermal Science 2024年第3期33卷 794-806页

作者： K JAMES Jintu kim Heuy dong Department of Mechanical Engineering Andong National UniversityAndong36729Republic of Korea CAD-IT Korea Co. Ltd.Seoul08591Republic of Korea

The oscillatory response of multiple shock waves to downstream perturbations in a supersonic flow is studied numerically in a rectangular *** shock waves are formed inside the duct at a shock Mach number of *** duct has an exit height of H,and the effect of duct resonance on multiple shock oscillations is investigated by attaching exit ducts of lengths 0H,50H,and *** downstream disturbance frequency varied from 10 Hz to 200 Hz to explore the oscillation characteristics of the multiple shock *** oscillatory response of shock waves under self-excited and forced oscillation conditions are analyzed in terms of wall static pressure,shock train leading-edge location,shock train length,and the size of the separation *** extent of the initial shock location increases with an increase in exit duct length for the self-excited oscillation *** analysis of the shock train leading edge and the spectral analysis of wall static pressure variations are *** variation in the shock train length is analyzed using the pressure ratio method for self-excited as well as forced *** RMS amplitude of the normalized shock train length(ζ_(ST))increases with an increase in the exit duct length for the self-excited oscillation *** the downstream perturbation frequency is increased,ζ_(ST)is decreased for exit duct *** all exit duct designs and downstream forcing frequencies,the size of the separation bubble grows and shrinks during the shock oscillations,demonstrating the dependence on duct resonance and forced oscillations.

关键词： shock train downstream disturbance supersonic flow shock wave boundary layer interaction duct resonance flow separation

Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by Selective Nucleophilic Substitution of Phosphorus

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Nano-Micro Letters 2024年第10期16卷 618-637页

作者： Se In kim Woong-Ju kim Jin Gu Kang dong-Wan kim School of Civil Environmental and Architectural EngineeringKorea University02841 SeoulSouth Korea Nanophotonics Research Center Korea Institute of Science and Technology02792 SeoulSouth Korea

Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy ***,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery *** thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal ***,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H *** resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H *** doping concentrations are varied by controlling the amount of precursors or their mean free *** at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 *** improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state *** approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关键词： Li-ion battery Two-dimensional N-type siloxene Doping mechanism Kinetics