• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.119-135
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• 1993

The paper presents a generalized optimal active control algorithm for earthquake-resistant structures. The study included the weighting matrix configuration, stability, and time-delays for achieving control effectiveness and optimum solution. The sensitivity of various time-delays in the optimal solution is investigated for which the stability regions are determined. A simplified method for reducing the influence of time-delay on dynamic response is proposed. Numerical examples illustrate that the proposed optimal control algorithm is advantageous over others currently in vogue. Its feedback control law is independent of the time increment, and its weighting matrix can be flexibly selected and adjusted at any time during the operation of the control system. The examples also show that the weighting matrix based on pole placement approach is superior to other weighting matrix configurations for its self-adjustable control effectiveness. Using the time-delay correction method can significantly reduce the influence of time-delays on both structural response and required control force.

• Steel and Composite Structures
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• v.17 no.4
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• pp.371-386
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• 2014

This paper presents a tri-linear restoring force model based on the test results of 12 circular RC columns strengthened by CFRP strips under low cyclic loading. The pre-stress of CFRP strips and axial load ratio of specimens are considered as the affect parameters of the proposed model. All essential characteristics of the hysteretic behavior of the proposed model, including the hysteretic rules, main performance points, strength degradation, stiffness degradation and confinement effects are explicitly analyzed. The calculated results from the proposed model are in good agreement with the experimental results, which shows that the recommended model can be reliably used for seismic behavior predictions of circular RC columns strengthened by pre-stressed CFRP strips.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.115-116
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• 2015

원림은 조영가의 사상과 가치관이 반영되어 조영방식, 구성 등이 표출된다. 본 연구는 백거이의 창작작품을 통해 백거이의 원림의 특징을 파악하고 그의 원림이 중국원림에 끼친 영향을 분석하였다. 연구결과 백거이는 자신의 유교적체득과 심미의식을 반영하여 원림의 의미를 변화시켰고 후대 문인원림 형성에 영향을 주었다. 또한 태호석의 독특한 미를 발견하고 원림에 도입하였으며 원림 내 경관을 풍부하기 위해 산체와 수체를 융합하고 돌을 이용해 가산을 쌓는 등 원림을 치밀하게 조성하였다.

• Bulletin of the Korean Mathematical Society
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• v.48 no.6
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• pp.1137-1146
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• 2011

Let {$X_i$, $i{\geq}1$} be a sequence of i.i.d. nondegenerate random variables which is in the domain of attraction of the normal law with mean zero and possibly infinite variance. Denote $S_n={\sum}_{i=1}^n\;X_i$, $M_n=max_{1{\leq}i{\leq}n}\;{\mid}S_i{\mid}$ and $V_n^2={\sum}_{i=1}^n\;X_i^2$. Then for d > -1, we showed that under some regularity conditions, $$\lim_{{\varepsilon}{\searrow}0}{\varepsilon}^2^{d+1}\sum_{n=1}^{\infty}\frac{(loglogn)^d}{nlogn}I\{M_n/V_n{\geq}\sqrt{2loglogn}({\varepsilon}+{\alpha}_n)\}=\frac{2}{\sqrt{\pi}(1+d)}{\Gamma}(d+3/2)\sum_{k=0}^{\infty}\frac{(-1)^k}{(2k+1)^{2d+2}}\;a.s.$$ holds in this paper, where If g denotes the indicator function.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.300-300
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• 2012

A database is an organized collection of data, today typically in digital form. The data are typically organized to model relevant aspects of reality, in a way that supports processes requiring this information. A good database is designed for a specific use and is constructed with the possibility of growth. In this project, we collect music education data of the East Asia and try to build a database that can share the primary data based on this collection. Hence we can provide opportunity to study about Korea modern music and culture in a broader perspective. In this paper, we explore the database construction methodology for implementing on this project and we see over about data entry and management.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.625-634
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• 2013

Energy is a direct restriction to the working life of an underwater mooring platform (UMP). In this paper, a vertical axis water turbine (VAWT) is designed to supply energy for UMPs. The VAWT has several controlled blades, which can be opened or closed by inside plunger pumps. Two-dimensional transient numerical studies are presented to determine the operating performance and power output of the turbine under low ocean current velocity. A standard k-${\varepsilon}$ turbulence model is used to perform the transient simulations. The influence of structural parameters, including foil section profile, foil chord length and rotor diameter, on the turbine performance are investigated over a range of tip-speed-ratios (TSRs). It was found that turbine with three unit length NACA0015 foils generated a maximum averaged coefficient of power, 0.1, at TSR = 2.

• Korean Journal of Materials Research
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• v.29 no.12
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• pp.753-756
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• 2019

Orthorhombic dysprosium manganite DyMnO₃ with single phase is synthesized using solid-state reaction technique and the crystal structure and dielectric properties as functions of temperature and frequency are investigated. Thermally activated dielectric relaxations are shown in the temperature dependence of the complex permittivity, and the respective peaks are found to be shifted to higher temperatures as the measuring frequency increases. In Arrhenius plots, activation energies of 0.32 and 0.24 eV for the high- and low-temperature relaxations are observed, respectively. Analysis of the relationship between the real and imaginary parts of the permittivity and the frequencies allows us to explain the dielectric behavior of DyMnO₃ ceramics by the universal dielectric response model. A separation of the intrinsic grain and grain boundary properties is achieved using an equivalent circuit model. The dielectric responses of this circuit are discerned by impedance spectroscopy study. The determined grain and grain boundary effects in the orthorhombic DyMnO₃ ceramics are responsible for the observed high- and low-temperature relaxations in the dielectric properties.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.469-474
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• 2002

Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bumps reflowed by laser was superior than the solder bumps reflowed by hot air, and the microstructure inside the solder bumps reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn$_4$ layer and remnant Au element. Needle-like AuSn$_4$ grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni$_3$Sn$_4$ intermetallic compound was found at the interface of solder bump reflowed by hot air, AuSn$_4$ particles distributed inside the whole solder bump randomly. It is the combination effect of the continuous AuSn$_4$ layer and finer eutectic microstructure inside the solder bump reflowed by laser that resulted in higher shear strength.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.863-868
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• 1995

Electroacupuncture therapy was performed in 2 dogs with thoracolumbar disc disease. Case was a 3-year-old female chihuahua with a calcified disc between the 13th thoracic and 1st lumbar vertebrae. Treatment was done by electroacupuncture at San sho yu, Shen yu, Huan tiao and Fu yang-San yin jiao with the current of 0.5~8 volts, 30 Hz for 30 min. She could pass feces and urine 2 days, and walk 9 days after the beginning of the therapy. Case 2 Was a 6-year-old male cocker spaniel with 4 calcified discs(T12-T13, T13-L1, L2-L3 and L6-L7) and spondylosis(lumbosacral junction). Treatment was done by electroacupuncture at Tian ping, Bai hui and Pung kung yu with the current of 2~4 volts, 30 Hz for 20 min. He could pass feces 6 days, urine 8 days, and stand 21 days, after the beginning of the therapy.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.20-23
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• 1994

It is well known that the Boyd's theorem states the relation between the imaginary eigenvalues of discriminant H of Riccati equation (A, R, Q) and the singular value of transfer function, but it is only available for R .geq. 0 and Q .geq. 0. In this paper, we extend Boyd's theorem for two case, that is, R is symmetric, Q is sign definite, and R is sign definite, Q is symmetric. We give under the condition that there is a real symmetric solution of Riccati equation the relation between H has imaginary eigenvalue and the maximum eigenvalue of transfer functoin. Finally, we give a necessary and sufficient condition to determine whether H has imaginary eigenvalue under some conditions.