• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.720-723
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• 1996

The recent summer power peak crisis has been caused by excessive use of cooling loads at daily peak time in summer. The yearly load shape of KEPCO has gradually became very steep valley. Under this situation, more efficient DSM(Demand Side Management) tools are fully required for summer peak clipping and shaving. In this paper, the KEPCO's Jeju-Do model project for DSM, especially for Demand Controller, is presented. Demand Controller was evaluated to have the very high economical efficiency against the investment in equipment, as compared with another DSM tools. There were some serious problem to apply Demand Controller to many customers in the aspect to synchronization with KEPCO's watthour meter. But these problems have solved by Keyin's new Demand Controller using vision algorithm.

• 한국정밀공학회지
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• 제24권10호
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• pp.13-18
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• 2007

• 대한음성학회지:말소리
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• 제60호
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• pp.67-84
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• 2006

The purpose of this study is to find some acoustic parameters on frequency domain to distinguish the Korean nasals, $/m,\;n,\;{\eta}/$ from each other. The new parameters are devised on the basis of LTAS (Long Term Average Spectrum). The maximum peak amplitude and the relevant formant frequency are measured in low and high frequency range, respectively. The frequency of spectral valley and its energy level are also obtained in the specific frequency range of the spectrum. Spectral slope, total energy value in specific frequency range, statistical distribution of spectral energy like centroid, skewness, and kurtosis are suggested as new parameters as well. The parameters that show statistically significant differences across nasals are summerized as follows. 1) in syllable initial positions: the total energy value from 1,500 to 2,200 Hz(zeroENG); 2) in syllable final positions: the peak amplitude of the first formant(peak1_a), the formant frequency with maximum peak amplitude from 4,000 to 8,000 Hz(peak2_f), the maximum peak amplitude of the formant frequency from 4,000 to 8,000 Hz(peak2_a), and the total energy value from 1,500 to 2,200 Hz(zeroENG).

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.15-18
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• 1989

This paper presents a new algorithm for P-wave detection in the ECG signal. We detect the peak and valley point using significant point extraction algorithm with 9-point derivative. Because P-wave duration is changed according to heart-rates, we search for the R-peak and calculate the R-R interval time prior to the determination of P-wave duration threshold values in order to actively adapt to the change of P duration. We determine the parameters for P-wave detection and then P-peak, P-onset and P-offset are detected by these parameters. The results obtained from the proposed algorithm have detected successively P-wave almost more than 90%.

• Geomechanics and Engineering
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• 제13권3호
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• pp.411-429
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• 2017

A Spectral Element Method for 3D seismic wave propagation simulation is derived based on the three-dimensional fluctuating elastic dynamic equation. Considering the 3D real terrain and the attenuation characteristics of the medium, the topographic effect of Wenchuan earthquake is simulated by using the Spectral Element Method (SEM) algorithm and the ASTER DEM model. Results show that the high PGA (peak ground acceleration) region was distributed along the peak and the slope side away from the epicenter in the epicenter area. The overall distribution direction of high PGA and high PGV (peak ground velocity) region is parallel to the direction of the seismogenic fault. In the epicenter of the earthquake, the ground motion is to some extent amplified under the influence of the terrain. The amplification effect of the terrain on PGA is complicated. It does not exactly lead to amplification of PGA at the ridge and the summit or attenuation of PGA in the valley.

• Food Science and Biotechnology
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• 제18권4호
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• pp.855-860
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• 2009

Physicochemical properties of starches isolated from 3 new potato cultivars developed by Potato Valley Ltd. were investigated and compared to those of starch isolated from 'Superior' being distributed prominently in Korea. Significant differences were observed in physicochemical properties such as granule size, amylose content, phosphorus content, water binding capacity, swelling power, solubility, and in vitro digestibility of starches from different potato cultivars. Thermal properties were evaluated using differential scanning calorimetry (DSC), and onset gelatinization temperatire ($T_o$), peak temperature ($T_p$), and enthalpies of gelatinization (${\triangle}H$) of different potato cultivars ranged as $58.0{\pm}0.3-61.7{\pm}0.4^{\circ}C,\;63.7{\pm}0.2-$ $66.5{\pm}0.0^{\circ}C$, and $15.6{\pm}0.5-17.0{\pm}0.3$ J/g, respectively. Pasting properties were evaluated using a rapid visco analyzer (RVA), and pasting temperature, peak viscosity, and final viscosity of different potato cultivars ranged as $65.0{\pm}0.1-68.9{\pm}0.1^{\circ}C$, $8,163.7{\pm}196.3-9,035.7{\pm}6.4$ cp, and $4,397.7{\pm}166.7-7,025.0{\pm}271.3$ cp, respectively. Especially, 'Gogu valley' starch showed the highest values in the amylose and phosphorus content among tested potato cultivars and higher water binding capacity, swelling power, and solubility than those of other tested starches. And it also showed high pasting temperature, peak viscosity, trough viscosity, and final viscosity as compared to other tested starches.

• 전력전자학회논문지
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• 제23권1호
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• pp.59-65
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• 2018

A new single-stage flyback power converter with PFC for electrolytic capacitor-less LED driver is proposed in this study. This method minimizes the peak-to-average ratio of the LED driving pulsating current by adding the LED driving current near the LED current valley area, as well as the third harmonic component injection into the input current. The reduced peak current value of the LED drive current minimizes the thermal stress of the LED itself, thereby increasing the reliability of the LED, as well as achieving a long lifetime. Simulation and experimental results show the usefulness of the proposed topology.

• 한국지형학회지
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• 제15권2호
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• pp.95-109
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• 2008

경상우도 동천구곡은 속리산과 덕유산 일대의 골짜기에 주로 분포하며, 화강암 지형 경관이 주축을 이룬다. 특히 하천의 암반 하상에 넓게 펼쳐진 너럭바위가 그 대표적 지형 경관이라 할 수 있다. 반면에 경상좌도 동천구곡은 경북 일대 태백 산지의 골짜기에 주로 분포하며, 퇴적암 지형 경관이 주축을 이룬다. 경북 일대 태백 산지의 골짜기에는 낙동강이 흐르는데, 동천구곡은 주로 낙동강의 지류를 따라 분포한다. 낙동강의 지류들은 태백 산지 내에서 곡류 하도를 이루며, 이에 따라 공격면 상에는 수직 절벽이 발달하고 그 아래에는 소가 나타난다. 보호면에 해당하는 포인트바는 주로 자갈 중심의 사력퇴가 발달하여 여울을 이루고 있다. 따라서 경상우도 동천구곡은 수평적 경관미를 담고 있다면, 경상좌도 동천구곡은 수직적 경관미가 탁월하다고 할 수 있다. 선인들은 동천구곡의 지형경관을 절벽(絶壁), 봉(峯), 담(潭), 탄(灘),천사(川沙), 폭(瀑), 대(臺) 등으로 이름 지어 불렀다.

• 한국농림기상학회지
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• 제13권2호
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• pp.79-86
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• 2011

산간계곡에는 특히 야간에 찬 공기가 흘러 고이는 일이 흔한데, 이런 곳의 식생은 생장과 발육이 그렇지 않은 주변지역에 비해 달라질 수 있어 관심의 대상이 다. 이 연구는 작은 규모의 집수역에서 적외선 영상을 이용하여 냉기호와 온난대의 형상을 가시화 할 수 있는지 알기 위해 수행하였다. 경남 하동군 악양면 형제봉(해발 1,117m)에 적외선 영상 복사계를 설치하여 관측여건이 양호했던 2011년 5월 17일 새벽부터 일출시까지 악양계곡의 열영상을 $640{\times}480$ 해상도로 획득하였다. 열영상 분석결과 계곡의 바닥에 나타난 낮은 온도 분포에 의해 찬공기의 배수를 인지할 수 있었고, 계곡 양쪽 사면에서 바닥보다 $5^{\circ}C$ 높은 온난대의 실체를 확인할 수 있었다. 적외선 영상을 이용하면 기존 고해상도 디지털 기온분포도 '전자기후도'의 신뢰성 검증이 한층 수월해져서 전자기후도 실용성 확보에 도움이 될 것이다.

• 전력전자학회논문지
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• 제24권2호
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• pp.134-137
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• 2019

A wide-bandwidth current controller is required for fast charging/discharging of super capacitor applications. Peak current mode is generally used to accomplish fast charging/discharging because this mode has fast response characteristics. However, the peak current mode control must have a slope compensation function to restrain sub-harmonics oscillation. The slope must be changed accordingly if the controlled output voltage is varied. However, changing the slope for every changed output voltage is not easy. The other solution, selecting the slope as the maximum value, causes a slow response problem to occur. Therefore, we propose a hybrid mode controller that uses a peak current and a newly specified valley current. Through the proposed hybrid mode control, the sub-harmonic oscillation does not occur when the duty is larger than 0.5 because of the fast response.