• 전기학회논문지
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• 제57권7호
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• pp.1195-1199
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• 2008

In this paper, peak detector of generator's output voltage and variable gain controller are introduced for a fast dynamic response. The conventional r,m.s, signal detected has inherent time delay, and the dynamic response of generator using conventional PID controller has some problem in sudden load change. In this paper, the peak detector and signal selector with variable gain controller is used to overcome this problem. The main controller can check the voltage state from the peak detector. When a sudden load change, the over-voltage and under-voltage signal from peak detector change the controller's gain and exciter's current reference. The proposed scheme can improve the dynamic response, which is verified from experimental test of 200kW diesel engine-generator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1088-1090
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• 1993

This paper shows efficient peak demand control method in office buildings. With a rapid growth of national economics and living standard, electrical energy consumption markedly increased. Expecially, it is increased electrical energy comsumption in the office buildings and thus an energy conservation through efficient use of electricity became more important. From the data of electric equipment capacity and electric power consumption for 96 buildings, current levels of demand factor and a growth trend of peak loads by office buildings were surveyed and analyzed. In addition the efficient peak demand control method in office buildings were studied.

• 한국철도학회논문집
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• 제16권5호
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• pp.372-378
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• 2013

이 논문에서는 도시철도의 최대수요전력 산출을 위한 근사모델을 제시한다. 전류 벡터 반복법을 활용하여 변전소의 최대수요전력을 계산할 경우에 기존의 방법으로는 수 많은 반복 조류계산이 필요하기 때문에 계산시간 제약으로 인해 실시간 적용이 어렵다는 문제가 있다. 본 논문에서는 모든 조건이 동일한 상태에서 전원 임피던스의 변화에 따른 변전소 최대수요 전력을 빠르게 산출하는 근사모델을 제시한다. 제시된 근사 모델에 의한 산출결과가 기존 모델과 거의 유사한 정확성을 보임을 시뮬레이션을 통해 예시한다.

• 말소리와 음성과학
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• 제4권3호
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• pp.43-49
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• 2012

This paper describes the categorical effects of pitch accent contrasts in a mimicry task. It focuses, specifically, on examining how fundamental frequency (f0) variation reflects phonological contrasts from speakers of two distinct varieties of Korean (i.e., North Kyungsang and South Cholla). The results showed that, in a mimicry task using synthetic speech continua, there was a categorical effect in f0 peak timing for North Kyungsang speakers, but the timing of f0 peaks and valleys in the responses of South Cholla speakers was more variable, presenting a gradient or non-categorical effect. Evidence of categorical effects was represented as the shift of f0 peak times along an acoustic continuum for North Kyungsang speakers. The range for the shift of f0 valley times was much narrower, compared to that of f0 peak times. The degree of a shift near the middle of the continuum showed variability across individual mimicry responses. However, the categorical structure in mimicry responses regarding the clustering of f0 peak points was more significant for North Kyungsang speakers than for South Cholla speakers. Additionally, the finding of the current study implies that the location of f0 peak times depends on individuals' imitative (or cognitive) abilities.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2003년도 춘계학술논문발표회논문집
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• pp.164-170
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• 2003

In this paper, we studied on the firing characteristics and electrical fire analysis of power cord deteriorated by thermal stress. The cross section of PVC insulating cord deteriorated by indirect flame decreased through heat convection. PVC insulating cord deteriorated by direct flame was bumpy shape. The exothermic peak of normal cord was shown at ($526.7^{\circ}C$), but the peaks or on(heat treatment temperature) ($150^{\circ}C$) cord was shown at ($299.6^{\circ}C$) and [$502.2^{\circ}C$]. The exothermic peaks according to high temperature were similar to those of amorphous carbon. In the FT-IR analysis, the absorption peak of normal cord indicated double bond of oxygen and carbon in benzene ring at 1720.0$cm^{1}$. As the HTT was high, the height of characteristic peak decreased and the peak of carbonyl group was shown at about 1625.7$cm^{-1}$. The characteristic peak of single bond(O-H) was shown at about 3479.2$cm^{-1}$. In case of the internal part of wire covering deteriorated by over current, the characteristic peak were shown at about 3417.3$cm^{-1}$ and 1600.2$cm^{-1}$. The above results show that we can distinguish the differences according to the fire pattern through the internalㆍexternal analysis of wire covering deteriorated by heat.

• 대한전기학회논문지
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• 제34권4호
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• pp.144-152
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• 1985

This paper temperature gradient thermally stimulated surface potentian (TG-TSSP) in measurements are applied to the study of the polarity of trapped and ionic carriers in cross-linked polyethylene (XLPE) filsm. In the thermally stimulated current in uniform temperature (TSC) of XLPE five peaks appear as indicated of the A B C D and E. In this paper A (at about -120$^{\circ}C$) D (at about 70$^{\circ}C$) and E (at about 110$^{\circ}C$) peaks are investigated. A peak is due to the biassing voltage and biassing temperature. Appear in to the glass transition temperature territory and caused in to the polarization of dipole. D peak is due to the depolarization of ionic space charge and E peak due to the detrapping of carriers injected from the electrodes. TG-TSSP and TSSP are measured to study the polarity of ionic carrier (D peak). In the unsatureated region of ionic space charge polarization, TG-TSSP is lower than TSSP during the initial stage of heating. Result of the experiment for E peak, TG-TSSP is higher than TSSP during the initial stage of heating and these results do not depend on the polarity of biassing voltage, and E peak is concerned with positive carriers (Holes).

• 한국전기전자재료학회논문지
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• 제18권3호
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• pp.269-275
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• 2005

A flux lock-type SFCL consists of two coils which are wound in parallel each other through an iron core, and a HTSC thin film connects in series with coil 2. The operation of the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between coil 1, coil 2. When a fault occurs, the fault current in the HTS thin film exceeds the critical current so that resistance is generated in the HTS film, and thereby the fault current is limited by an instant rise in the impedance of the flux-lock type SFCL. We investigated he variances of initial fault current limiting instant according to the ratio of inductance of coil 1 and coil 2 in the flux-lock type SFCL. It was confirmed from experiments that the initial fault current limiting instant in the subtractive polarity and additive polarity windings were faster as the ratio of coil 2' inductance for coil 1's inductance increased. The 1st peak of fault current in case of the subtractive polarity winding was higher as the ratio of coil 2's inductance for coil 1's inductance increased. On the other hand, in case of the additive polarity winding, the 1st peak of fault current was lower.

• 한국정보통신학회논문지
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• 제21권9호
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• pp.1818-1825
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• 2017

ADCP(Acoustic Doppler Current Profiler) 는 초음파의 도플러 효과를 이용하여 수중에서 유속의 측정 및 교란 정도를 분석한다. 따라서 수신되는 각 공간 영역에 대한 속도 정보를 추출하기 위하여 수신 펄스 신호에 대한 자기 상관 함수나 FFT(Fast Fourier Transform) 스펙트럼을 추정한다. 그러나 자기 상관 함수 추정은 수신되는 반사 신호가 가우시안 형태의 대칭적인 도플러 스펙트럼을 가진다는 가정이 필요하며 이러한 조건이 만족 되지 않는 경우 추정치에서의 큰 편향오차가 발생할 수 있다. 또한 유속의 변화가 빠르게 나타나는 경우 신호 획득시간이 짧아 유속을 측정하기 위한 자기 상관 함수 나 FFT 스펙트럼의 정확한 추정이 어렵다. 따라서 본 논문에서는 반사 신호가 대칭형 또는 비대칭형 가우시안 형태의 스펙트럼을 보이면서 상대적으로 짧은 반사 획득 신호인 경우에도 정확한 유속 추정이 가능한 AR(Autoregressive) 스펙트럼 첨두치 추정 방법을 제안하였다. 이러한 방법을 이용하면 기존 방법에 비하여 그 정확도를 개선할 수 있음을 보였다. 제안된 방법의 평가를 위하여 다양한 환경에서의 모의 신호들을 구현하였으며 그 결과들을 비교하고 분석하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권1호
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• pp.23-29
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• 2005

This paper presents the characteristics of leakage currents flowing through ZinC Oxide(ZnO) surge arrester blocks under mixed direct and 60 Hz alternating voltages. A mixed voltage, in which an alternating voltage is superimposed upon a direct voltage, appears on the HVDC system network. The mixed direct and alternating voltage generator with a peak open-circuit of 10 kV was designed and fabricated. The leakage currents and V-I curves for the fine and used ZnO surge arrester blocks were measured as a function of the voltage ratio k, where the voltage ratio k is defined as the ratio of the peak of alternating voltage to the peak of the mixed voltages. The resistive component in the leakage current in the low conduction region is significantly increased with increasing the voltage ratio k. The V-I characteristic curves for the mixed voltages lies between the direct and alternating characteristics, and the cross-over phenomenon in the high conduction region was appeared.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.273-276
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• 1997

This paper describes the thermally stimulated current (TSC) measurements of arachidic acid and polyamic acid alkylamine salt(PAAS) LB film, which is a precursor of polyimide(PI). The measurements were performed from room temperature to about 25$0^{\circ}C$ and the temperature was increased at a rate of 0.02 K/s linearly. It shows that peaks of TSC are observed at about 8$0^{\circ}C$ in the arachidic acid and about 8$0^{\circ}C$, 16$0^{\circ}C$ in the PAAS LB films. Results of these measurements indicate that one peak at 8$0^{\circ}C$ is resulted from alkyl group; the other peak at 16$0^{\circ}C$ is due to alkyl and C-O group of PAAS. Additional large peak at about 16$0^{\circ}C$ is due to dipole moments in the PAAS films. The DSC of PAAS, arachidic acid and octadesylamine are measured. Thermal imidization was performed at 30$0^{\circ}C$ for 1 hour by our pre study.