• 전력전자학회논문지
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• 제27권5호
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• pp.376-383
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• 2022

The improved performance of computer parts, such as graphic card, CPU, and main board, has led to the need for power supplies with a high power output. The dynamic load profile rapidly changes the usage of power consumption depending on load operations, such as PC power and air conditioner. Under dynamic load profile conditions, power consumption can be classified into maximum, normal, and standby power. Several problems arise in the case of maximum power. Peak power is generated at the system power source in the maximum-power situation. Frequent generation of peak power can cause high-frequency problems and reduce the life of high-pressure parts (especially high-pressure capacitors). For example, when a plurality of PCs are used, system overload occurs due to peak power generation and causes problems, such as power failure and increase in electricity bills due to exceeded contract power. To solve this problem, a system peak power limit/compensation power circuit is proposed for a power supply under dynamic load profile conditions. The proposed circuit detects the system current to determine the power situation of the load. When the system current is higher than the set level, the circuit recognizes that the system current generates peak power and compensates for the load power through a converter using a super capacitor as the power source. Thus, the peak power of loads with a dynamic load profile is limited and compensated for, and problems, such as high-frequency issues, are solved. In addition, the life of high-pressure parts is increased.

• 한국통신학회논문지
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• 제18권7호
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• pp.1036-1043
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• 1993

대기압 MOCVD방법으로 이중 장벽 구조의 공명 투과 소자를 제작하여 상온과 77K에서의 부저항 특성을 특정하였다. GaAs 양자 우물과 spacer, AIGaAs 장벽을 사용하여 성장온도를 변화시켜 공명 투과 소자를 제작한 결과 상온에서 2.35, 77K에서 15.3의 높은 peak-to-valley 전류비를 얻었다 컴퓨터 모의 실험에서는 coherent 투과만을 고려하여 peak 전류를 계산해서 실험치와 잘 일치하는 것을 알 수 있었다. AlGaAs 장벽에 InGaAs 양자 우물과 spacer를 사용하여 전자의 공급량을 증가시킨 구조에서는 상온에서 8.6KA/cm의 높은 peak 전류와 4.0의 큰 peak-to-valley 전류비를 얻었다.

• 비파괴검사학회지
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• 제33권6호
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• pp.505-510
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• 2013

An encircling send-receive type pulsed eddy current (PEC) probe is designed for use in aluminum tube inspection. When bare receive coils located away from the exciter were used, the peak time of the signal did not change although the distance from the exciter increased. This is because the magnetic flux from the exciter coil directly affects the receive coil signal. Therefore, in this work, both the exciter and the sensor coils were shielded in order to reduce the influence of direct flux from the exciter coil. Numerical simulation with the designed shielded encircling PEC probe showed the corresponding increase of the peak time as the sensor distance increased. Ferrite and carbon steel shields were compared and results of the ferrite shielding showed a slightly stronger peak value and a quicker peak time than those of the carbon steel shielding. Simulation results showed that the peak value increased as the defect size (such as depth and length) increased regardless of the sensor location. To decide a proper sensor location, the sensitivity of the peak value to defect size variation was investigated and found that the normalized peak value was more sensitive to defect size variation when the sensor was located closer to the exciter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.185-188
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• 2005

This paper proposes a new peak-windowing algorithm with window-length adaptation for peak-to-average power reduction (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. Conventional peak windowing algorithm has advantages, such as moderate system complexity with good spectral shape. However, adjacent peak signals within the length of window functions produce the distortion of signal amplitude since window functions might overap with each other. These undesired characteristics of conventional peak windowing algorithm result in the degradation of BER performance. The proposed algorithm outperforms the conventional one with the aid of window-length adaptation. Simulation results show the efficiency of the proposed algorithm under the environments of WiBro downlink systems.

• 한국진공학회지
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• 제10권2호
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• pp.247-251
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• 2001

실리콘산화막에 $Si^+$이온을 주입하여 열처리를 한 후 상온에서 8K까지 온도를 변화시키며 PL을 측정하였다. 상온에서 50~80K까지는 PL intensity가 전체적으로 증가하였으며 50K 이하에서는 감소하였다. PL intensity가 증가하는 동안 peaks는 blue-shift가 일어났다. PL spectrum에서 peak를 보이는 파장에서 PL의 온도의존성을 측정하였다. 첫 번째 peak가 온도변화에 가장 민감하며 크기가 작은 peak일수록 온도의 영향을 적게 받는다. PL peak의 온도의존성을 분석하였다. 상온에서 50K 범위에서 PL intensity 대 1000/T그림에서 온도역수의 3차 함수로 fitting할 수 있었다. 온도가 내려갈수록 PL intensity가 증가하는 것을 nanocrystal 보다도 O위주 결함(Si-O-O)이나 Si위주 결함(Si-Si-O)들의 quantum size effect로 설명할 수 있었다.

• 한국진공학회지
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• 제6권S1호
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• pp.34-42
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• 1997

Hg-Te-CdTe superlattices have received much interests over the last several years as a potential material for its applications for detecting devices and optoelectronics. We have grown the HgTe-CdTe superlattice using MBE. in our lab. We have carried out DCRC spectroscopy after growth of HgTe-CdTe superlattice with varying the superlattice periods and controlling the barrier thickness and we have that the presence of the main peak and the satellite peaks. We obtained 20 arcsec of FWHM over 100 periods of superlattice. We also note that high peak intensity shows the high quality of the sample and each layer of superlattice has abrupt interfaces. The angular separation between the main peak(m=0) and the first satellite peak(m=$\pm$1) is increased when the barrier layer thickness in superlatice layers are decreased. The separation between the first setellite peak(m=$\pm$1) and the second satellite peak(m$\pm$2) is increased similarly. The number of the satellite peak is a qualitative measure of the interfacial abruptness of the superlattice.

• 한국환경과학회지
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• 제7권4호
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• pp.451-460
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• 1998

The objectives of this study Is to evaluate the total runoff yield, peak flow and peak flow travel time depending on the urbanization, return period and rainfall patterns at the downstream of Manchon urban watershed in TaeGu City. SWM(Storm Water Management Model) is used for runog analysis based on 5 different steps of urbanization and 4 different types of Hufrs quartile according to 8 return periods. It is analyzed that the order of total runoff yield according to raiun patterns is Huffs 4, Huffs 2. Huffs 3 and Huffs 1 quartile, that of peak flow magnitude is Huffs 2, Huffs 1, Huffs 4 and Huffs 3 quartile at present development ratio. under the 60, 70, 80 and 90ft of urbanization to the 50% of urbanization by means of the rainfall patterns, the mean Increasing ratio of total runoff yield for each case is 4.55, 11.43, 16.07 and 20.02%, that of peak flow is 5.82, 13.61, 17.15 and 18.83%, the mean decreasing ratio of peak flow travel time Is 0.00, 2.44, 5.07 and 6.26%, the mean increasing ratio of runoff depth Is 4.51, 11.42, 16.02 and 20.05% respectively. the mean increasing ratio of total runoff yield by means of each and 19.71%. Therefore, as the result of this study. it can be used for principal data as to storm sewage treatment and flood damage protection planning in urban small watershed.

• 전기학회논문지
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• 제67권10호
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• pp.1257-1264
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• 2018

This paper proposes Autoregressive Integrated Moving Average (ARIMA)-based forecasting algorithms using meteorological indices to predict seasonal peak load. First of all, this paper observes a seasonal pattern of the peak load that appears intensively in winter and summer, and generates ARIMA models to predict the peak load of summer and winter. In addition, this paper also proposes hybrid ARIMA-based models (ARIMA-Hybrid) using a discomfort index and a sensible temperature to enhance the conventional ARIMA model. To verify the proposed algorithm, both ARIMA and ARIMA-Hybrid models are developed based on peak load data obtained from 2006 to 2015 and their forecasting results are compared by using the peak load in 2016. The simulation result indicates that the proposed ARIMA-Hybrid models shows the relatively improved performance than the conventional ARIMA model.

• Journal of Astronomy and Space Sciences
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• 제29권3호
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• pp.253-258
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• 2012

We revisit the relation between the peak luminosity $L_{iso}$ and the spectral time lag in the source frame. Since gamma-ray bursts (GRBs) are generally thought to be beamed, it is natural to expect that the collimation-corrected peak luminosity may well correlate with the spectral time lag in the source frame if the lag-luminosity relation in the GRB source frame exists. With 12 long GRBs detected by the Swift satellite, whose redshift and spectral lags in the source frame are known, we computed $L_{0,H}$ and $L_{0,W}$ using bulk Lorentz factors ${\Gamma}_{0,H}$ and ${\Gamma}_{0,W}$ archived in the published literature, where the subscripts H and W represent homogeneous and wind-like circumburst environments, respectively. We have confirmed that the isotropic peak luminosity correlates with the spectral time lag in the source frame. We have also confirmed that there is an anti-correlation between the source-frame spectral lag and the peak energy, $E_{peak}$ (1 + z) in the source frame. We have found that the collimation-corrected luminosity correlates in a similar way with the spectral lag, except that the correlations are somewhat less tight. The correlation in the wind density profile seems to agree with the isotropic peak luminosity case better than in the homogeneous case. Finally we conclude by briefly discussing its implications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1615-1618
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• 1987

시간 영역에서 만들어진 음성신호의 파라미터을 이용하여 주어진 음성신호의 구간이 유성음, 무성음, 혹은 묵음인지를 분류하는 새로운 알고리듬을 제시하였다. 이에 사용한 파라미터은 구간내에서 샘플링된 값의 절대치 합과 일정한 level 이상의 peak의 합(T-peak), T-peak와 절대치 합의 비 그리고, DPCM의 절대치 합들이다. 이를 파라미터를 이용하여 간단히 유성음/무성음/묵음 구간을 분류 할였다. This paper proposes new algorithm for classifying speech signal frame into voiced, unvoiced, silence frame, using the parameters extracted from time domain behavior of speech signal The parameters used in this paper are absolute magnitude, the sum of peaks lager than reference level (T-peak), the ratio of T-peak to absolute magnitude and the magnitude of signal outputs of DPCM. Using this parameters, speech signal is more easily classified into voiced/unvoiced/silence frame.