• 방사성폐기물학회지
• /
• 제3권4호
• /
• pp.335-340
• /
• 2005

Single-pass flow-through (SPFW) 방법에 의한 유리고화체의 용해율 측정에서 정밀도를 구하기 위하여 연구소간 실험프로그램의 하나로서 붕규산유리고화체의 정용해율을 구하였는데, 이 SPFT 방법은 American Society for Testing and Materials (ASTM)에서 표준화를 위하여 작성되었다. 이를 위해 100/200 mesh 크기의 모의 저방사능 유리고화체 분말시료를 $70^{\circ}C$, 알곤 분위기에서 SPFT 방법으로 리튬 완충용액 (pH=10)을 이용하여 용해실험을 시도하였다. 얻어진 용출액 중 규소와 붕소의 농도에 따라 용해율의 변화를 구한 결과, 유리의 정용해율이 $2.7\times10^{-5}g{\cdot}m^{-2}{\cdot}s^-1$ 부근으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.136-136
• /
• 2009

It is investigated the cut-off frequency of Z-cut quartz microstrip low pass filter by the variation of applied electric field. Designed microstrip filter was simulated using the Ensemble v7.0(Ansoft). As a result of the experiment, the cut-off frequency showed 50 MHz shift when the applied electric field was 3 kV/cm.

• 산업기술연구
• /
• 제27권B호
• /
• pp.153-160
• /
• 2007

In this paper, the exact analysis of the parallel coupled line with open stub is presented. This structure shows LPF characteristics with broad stopband and sharp skirt characteristics. We derived the exact Z-matrix expression of the structure. In order to show the validation of the expression we designed $3^{th}$ order Chebyshev LPF using the structure. The simulated data excellently agreed with the predicted values by the calculation using the derived expression.

• 한국자동차공학회논문집
• /
• 제14권1호
• /
• pp.92-99
• /
• 2006

The swirl ratio of a charge in the cylinder was estimated by calculating the ratio of the rotary speed of charge which could be simulated from the rotary speed of paddle in the swirl measurement apparatus, to the engine speed which could be calculated by measuring intake air flow rate. The automation of the swirl ratio measurement for cylinder head was achieved by controling both valve lift in cylinder head and a suction pressure of surge tank using two step-motors. The number of measurement position for calculating mean swirl ratio was varied by adjusting the interval of valve lift. The mean swirl ratio with varying the number of measurement position showed nearly constant value. Two measurement methods for measuring the swirl ratio were compared, one was to control the suction pressure of the surge tank with PID (proportional, integral, differential) mode with by-pass valve controlled by the step motor and the other did not control the surge tank pressure by fixing the by-pass valve. The difference of the mean swirl ratio between the two measurement methods showed nearly constant value with varying the number of measurement position. This means that the w/o PID control method could be preferred to the PID control method which has been used, due to the simpleness of the swirl measurement.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
• /
• pp.93-96
• /
• 2002

This paper presents robust and efficient scene-based video watermarking method using visual rhythm (spatio-temporal slice) in compressed domain. Scene change can be detected easily using visual rhythm and video sequences are conveniently edited at the scene boundaries. Therefore, scene-based watermark embedding Process it a natural choice. Temporal spread spectrum can be achieved by applying spread spectrum methods to visual rhythm. Additive Gaussian noise, low-pass filtering, median filtering and histogram equalization attack are simulated for all frames. Frame sub-sampling is also simulated as a typical video attack Simulation results show that proposed algorithm is robust and efficient in the presence of such kind of attacks.

• Progress in Superconductivity
• /
• 제5권1호
• /
• pp.13-16
• /
• 2003

In this work, we have studied about an RSFQ (Rapid Single Flux Quantum) switch element. The circuit was designed, simulated, and laid out for mask fabrication. The switch cell was composed of a D flip-flop, a splitter, a confluence buffer, and a switch core. The switch core determined if the input data could pass to the output. “On” and o“off” controls in the switch core could be possible by utilizing an RS flip-flop. When a control pulse was input to the “on” port, the RS flip-flop was in the set state and passed the input pulses to the output port. When a pulse was input to the “off” port, the RS flip-flop was in the reset state and prevented the input pulses from transferring to the output port. We simulated and optimized the switch element circuit by using Xic, WRspice, and Julia. The minimum circuit margins in simulations were more than $\pm$20%. We also performed the mask layout of the circuit by using Xic and Lmeter.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.435-442
• /
• 2004

Tilting train allow the train to pass curve at higher speed without affecting passenger comfort. As the tilting trains run curve track about 30$\%$ higher than non-tilting trains, the centrifugal force and dynamic force will be higher. Therefore it is very important for tilting train to ensure safety against derailment, and to reduce the lateral track forces by applying light-weight design, optimized suspension design and steering mechanism. The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R & D project, was designed and analytically verified to meet these special requirements. This paper describes the analytic study to verify the safety against derailment, especially on the wheel unloading in case of tilting actuation. The severest curve geometry and curving speed was assumed, the tilting control pattern was also assumed as trapezoidal force function applied to tilting bolster and bogie frame. For the comparison, the operation with the speed of tilting train without tilting actuation was numerically simulated and the operation with the balanced speed without tilting actuation was also numerically simulated. Through the numerical simulation of various operating case, we found that derailment quotients, wheel unloading and Q/P was not affected by tilting actuation and that the bogie of TTX was nicely designed to satisfy the safety against the derailment.

• 한국항해항만학회지
• /
• 제34권6호
• /
• pp.453-458
• /
• 2010

이 연구에서는 장기간의 기상 자료를 이용하여 지구 온난화와 태풍의 변화 경향과의 관계를 분석하였다. 연구 결과에 의하면, 태풍의 연 평균 발생 수는 감소하고, 태풍 역내의 최대풍속은 서서히 강해지는 추세를 보인다. 이는 대부분의 수치 시뮬레이션 결과와 일치한다. 그리고 태풍의 정상진로는 증가하는 추세를 보이는 반면 서진형진로는 감소하는 경향을 나타낸다. 최근 10년간의 태풍의 이동경로는 정상진로 6 : 서진형진로 3 : 이상진로 1의 비율을 보인다. 우리나라에 영향을 미치는 태풍은 남해안을 통과하는 것이 가장 많다. 최근에는 서해안을 통과하는 태풍의 수가 감소하고 동해안을 통과하는 태풍의 수는 증가하는 추세를 보인다. 지구 온난화와 관련하여 특히 주목할 점은 태풍의 세기가 점점 강해지고 있다는 사실이다. 기상재해의 예방 관점에서 이에 대한 주의와 대책이 요구된다.

• 한국통신학회논문지
• /
• 제32권6A호
• /
• pp.648-656
• /
• 2007

본 논문은 S-라인(비방사 마이크로 스트립)을 이용하여 무선 가입자 회선(WLL) 및 지역 다지점 분배 서비스(LMDS) 등 광대역 무선 가입자 망으로의 기술 적용을 위한 밀리미터 대역의 중심주파수 37GHz에서 세라믹을 이용한 대역 통과 필터에 관한 것이다. 아래 위가 도체로 덮인 유전체 기판 위의 선로 사이에 세라믹 공진기를 삽입시켜, 구조적 공진 특성을 이용함으로써 필터 특성을 얻어내는 방법으로 제작하였다. 이러한 필터 구조와 특성을 근거로 한 시뮬레이션을 하여, 1단 세라믹 공진기의 공진주파수를 찾는 공식과 4단 세라믹 공진기의 대역을 구하는 공식을 일반화 하였다. 또한, 4단 세라믹 공진기의 시뮬레이션 결과를 바탕으로 제작된 실험 구조물을 Network Analyzer를 사용하여 실험을 실시하였으며, 시뮬레이션 결과의 대역은 36.58GHz-37.650GHz, 리플과 손실은 -ldB 이내. Cutoff 특성은 S(2,1)그래프의 대역 좌우로 -35dB밑으로 1GHz이내인 것에 대하여 실험 결과의 대역은 36.6GHz-37.65GHz, 손실은 -ldB이내, 리플은 -3dB이내, Cutoff 특성은 S(2,1)그래프의 대역 좌우로 -30dB밑으로 1GHz 이내인 특성을 나타내었다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.1433-1437
• /
• 2007

This paper describes the detection algorithm which can distinguish series arcing signal from voltage harmonics or noises produced by the operation of non-linear loads. A high pass filter with the cutoff frequency of 3 kHz is designed and it can attenuate power frequency signal to 80 dB. Series arcing phenomena is simulated to an incandescent lamp controlled by a dimmer. From the experimental results, it is confirmed that the amplitude of the filter output voltage varies at random during series arcing but the signal generated by non-linear loads appears on a regular basis. We proposed a series arcing detection algorithm using the chaotic nature of voltage signal.