• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.495-502
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• 2016

In this paper, time and frequency domain characteristics of Gyeong-ju earthquakes were investigated, and nonlinear time history analyses were conducted for bi-linear hysteretic structures excited by short-duration ground accelerations. Previous studies showed that larger inelastic displacements than the peak displacement of the corresponding elastic system were observed especially for the structures with structural period shorter than 0.3s, and the similar results could be obtained when long-duration ground accelerations were used as excitation loads. For the short-duration earthquakes, however, the inelastic displacements were not so large and almost identical to the peak elastic displacements.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.12
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• pp.45-50
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• 1994

The elliptic filters are optimal in the sense that the magnitude characteristic exhibits the steepest slope at the cutoff frequency. The other characteristics such as delay and step response, however, are rather undesirable. In this paper, the modified elliptic low-pass filter function is proposed. The modified elliptic function possesses progressively diminishing ripples in both passband and stopband, and the lower pole-Q, values when compared to the elliptic counterparts, thus producting the flatter delay characteristics and improved time-domain performances. And it is realizable in the doubley-terminated ladder structures for the order n even or odd, thus lending themselves amaenable to high-quality active RC or switched capacitor filters through the simulation techniques.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.339-342
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• 2005

This paper presents the development of a method for determining the response modification factor, using traffic load. The proposed method is based on the results of computer simulations of traffic action effects. The simulation program generates random traffic actions for defined traffic conditions and determines the frequency distribution of maximum traffic action effects. Therefore, this study is adopted to long-span bridge for the verification of the proposed method. A comparison between the proposed method and present method shows good agreement in estimating the modified load carrying capacity of bridges.

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.93-104
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• 1986

The purpose of this study was to see that how about the related variables influence on the use of the microwave oven and how about the use of the microwave oven influence on the time spent in meal preparation and meal management. Questionaires were give to randomly selected homaker's, in kwangju in August, 1986. Data from the 149 response were analyzed according to multiple regression. The results were as follows; 1. The variables affecting the use of the microwave oven were family income, homaker's employed hours, homakers' education level, a period of use a microwave oven, congnition of a special character in a microwave oven, family style of participation in meal preparation, frequency in use of instant food. 2. The variables of the use the microwave oven was significantly influence on the time spent in meal preparation. 3. The variables of the use the microwave oven was not significantly influence on meal management.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.1-8
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• 2000

The time simulation of motion responses of dolphin-moored BMP in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The hydrodynamic coefficient and first order wave exciting forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The second order wave drift forces and mooring for dolphin system are taken into account. As for numerical example, time domain analysis are carried out for a BMP in irregular wave condition.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.203-206
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• 2000

In this paper, we discuss an efficient steady-state analysis of reactance oscillators having multiple oscillations. Our oscillator is consisted of the Cauer or Foster reactance sub-circuit and a negative resistor such as tunnel diode. The reactance circuit has many resonance and antiresonance points on the frequency response curve. Such a circuit having the specified resonance and anti-resonance points can be easily synthesized with the fundamental circuit theory. In this case, the multiple oscillations may occur near at the anti-resonance points. We have developed a user friendly simulator for getting the exact steady state responses using the SPICE.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.56-62
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• 1998

One of the key components to accomplish WDM all-optical network is an arrayed waveguide grating router. The spectral characterisitc of the ypeical arrayed waveguide grating rouger has parabolic shape, hence the bandwidth is limited. The spectral response of an optical filter should be as flat as possible for the reliable operation of the syste, because the center frequency of the optical source could be deviated in the actual system. In order to acquire these characteristics, we propose and design a new type of the arrayed waveguide grating router with a flat passband using the Fourier optics concept. The BPM simulation results of the new arrayed waveguide grating router with the flat passband show that the bandwideth is 0.8 nm at -1 dB, instertion loss about 6 dB, and the crosstalk less than -23 dB fro each cnannel, which is 1.6 nm(200 GHz) separated from the adjacent channel around 1550 nm wavelength range.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.617-626
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• 1999

For the purpose of high speed and reliable data transmission through the frequency response variation channel by load fluctuation, we present CSK signal transmission characteristics by computer simulation. Also using the simple structure of Roll-off filter at the CSK receiving system, the exact synchronization tracking and data detection without error at the worst case of S/I=2 and S/N=2 were achieved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.374-379
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• 2010

In this paper, we have mathematically analyzed lumped element type negative group delay circuit (NGDC) and derived general design equation. The applicability of the proposed design equation is validated with mathematical and circuit simulation as well as with experimental results for intentional mobile telecommunication 2000 (IMT-2000) downlink band. As a design example, single branch NGDC with -0.8ns of group delay (GD) for narrow bandwidth of the specific frequency is simulated and fabricated. Finally, $\pi$-network NGDC is proposed and validated to obtain wideband GD response of $-1.7{\pm}0.06$ nsec for 60 MHz.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.131-132
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• 2007

This paper presents a numerical solution of PID controller design. The complete set of PID controllers stabilizing an LTI plant that solely determined from the knowledge of the frequency response and the number of unstable poles of the plant. An illustrative example is given to describe implementation of the design algorithm and exhibit graphical displays of the feasible regions of the design parameters.