• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.658-665
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• 2011

In the present paper, a novel fast peak detector for single- or three-phase unsymmetrical voltage sags is proposed. The proposed detector is modified from a single-phase digital phase-locked loop based on a d-q transformation using an all-pass filter (APF). APF generates a virtual phase with $90^{\circ}$ phase delay. However, this virtual phase cannot reflect a sudden change of the grid voltage in the moment of voltage sag, which causes a peak value to be significantly distorted and to settle down slowly. Specifically, the settling time of the peak value is too long when voltage sag occurs around a zero crossing, such as phase $0^{\circ}$ and $180^{\circ}$. This paper describes the operating principle of the APF problem and proposes a modified all-pass filter (MAPF) to mitigate the inherent APF problem. In addition, a new fast peak detector using MAPF is proposed. The proposed detector is able to calculate a peak value within 0.5 ms, even when voltage sag occurs around zero crossing. The proposed fast peak detector is compared with the conventional detector using APF. Results show that the proposed detector has faster detection time in the whole phase range. Furthermore, the proposed fast peak detector can be effectively applied to unsymmetrical three-phase voltage sags. Simulation and experimental results verify the advantages of the proposed detector and MAPF.

• 한국수자원학회논문집
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• 제43권7호
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• pp.635-643
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• 2010

작은 규모 유역의 홍수 유출량을 산출하기 위해서 유역을 대표하는 하나의 단위유량도를 많이 적용해 왔다. 이 때 단위유량도의 첨두유량과 첨두 발생시간은 단위유량도를 결정하는 특성치로 취급된다. 본 연구에서는 국내에서 $8.5\;km^2$ 정도의 소규모 유역에서도 강우 사상별로 단위유량도의 첨두유량과 발생시간은 상당히 변동되는 것을 보이고 분석하였다. 그리고 동일 소유역에서 단위유량도 변동의 주요인으로 강우 사상별 평균 강우강도라고 보고 강우 사상별 강우강도와 단위유량도의 첨두유량 및 발생시간의 관계를 각각 지수함수식으로 제시하였다. 결과적으로 사용 자료상의 제약 등으로 단위유량도 첨두치에상당한 분산을 동반하는 한계는있지만 연구된 대로 단위유량도의첨두유량 및 첨두 발생시간과 강우의 평균적인 회귀 관계는 단위유량도 이론의 보완적 측면에서 수문학적 가치를 갖는다.

• 대한물리치료과학회지
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• 제8권2호
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• pp.967-976
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• 2001

The purpose of the present study was to the investigate the effect of aging in men and women on muscle strength of knee extensor and flexors by using the cybex 6000 isokinetic dynamometer. A total of 100 volunteers participated in this study and were divided into five groups according to their chronological age as follows: 20s, 30s, 40s, 50s, 60s, 10 men and 10 women in each decade respectively. Isokinetic ($60^{\circ}{\cdot}s-l$) knee extensor and flexor peak torque, peak torque to body weight ratio, opposing muscles(flexor/extensor) peak torque ratio, deficit of peak torque between dominant and non-dominant were measured. The results obtained were as follows: 1) In men, While the aged increased. the peak torque of the knee flexor and extensor statistically sig nificant decreased in the dominant and non-dominant side. 2) In women, Statistically significant difference of knee extensor peak torque was found as the aged increased in the dominant and non-dominant side, but significant difference of knee flexor peak torque did not that. 3) In men, No significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the non-dominant side, but statistically significant difference in the peak torque of knee flexor to body weight weight ratio was found as the aged increased in the dominant side. 4) In women. No significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the dominant side, but statistically significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the non-dominant side. 5) In men and women, While the aged increased, statistically significant difference was found the dominant and non-dominant side in the peak torque of knee extensor to body weight ratio. 6) Peak torque of hamstring to quadriceps ratio of dominant and non-dominant side in men and women were not significantly different as the age increases. 7) Mean deficit of peak torque between dominant and non-dominant side in men and women were not significantly different as the age increases. From these results we conclude a proper exercise program is need before 50s decade to preserve in muscle strength of knee flexors and extensors.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2315-2321
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• 2013

본 연구는 혈류에 의한 조영제 peak time을 산출하는 새로운 방법을 개발하여 기존의 수식에 의한 부작용을 최소화 하고, 대체할 수 있는 새로운 검사법을 제시하고자 하였다. 시험적조영제주입법을 이용하여 CE MRA를 검사한 환자 127명을 대상으로, 기존의 수식에 의해 산출된 조영제 peak time이 조영제 주입 후 혈류에 의한 영상화 범위의 어느 뇌혈관 측정값과 일치하는지 각 뇌혈관의 조영제 inflow time과 peak time을 측정하였다. 연구결과, 유의수준 0.05에 대한 4개의 집단 간 차이가 존재하였으나 집단 1에서 수식에 의해 산출된 조영제 peak time과 S상 정맥동의 조영제 inflow time이 통계적으로 유의한 차이가 없어 일치하였으며, Bland Altman plot를 시행한 결과 일치도가 상당히 높은 것을 확인할 수 있었다. 따라서 본 연구의 혈류에 의한 새로운 방법을 적용한다면, 부작용 가능성을 최소화하고, 영상의 질은 유지하면서, 쉽고 빠르게 적용할 수 있어, 기존의 수식에 의해 산출된 조영제 peak time을 대체 할 수 있으리라 사료된다.

• 운동영양학회지
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• 제24권4호
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• pp.28-33
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• 2020

[Purpose] This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplement on delayed onset muscle soreness (DOMS) by analyzing the maximum muscle strength and indicators of muscle damage. [Methods] Twelve men with majors in physical education were assigned to the BCAA group and placebo group in a double-blinded design, and repeated measurements were conducted. DOMS was induced with an isokinetic exercise. Following BCAA administration, the changes in the knee extension peak torque, flexion peak torque, aspartate aminotransferase (AST), creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were analyzed. The maximum knee muscle strength was measured at the baseline (pre-D0) following BCAA administration for 5 days before exercise (-D5, -4D, -3D, -2D, -1D). In contrast, the post-treatment measurements (D3) were recorded after BCAA administration for 3 days (post-D0, D1, D2). Blood samples were obtained before (pre-D0), immediately after (post-D0), 24 h (D1), 48 h (D2), and 72 h (D3) after the exercise to analyze the indicators of muscle strength. BCAA was administered twice daily for 8 days (5 days and 3 days before inducing DOMS and during the experimental period, respectively). [Results] There was no difference in the flexion peak torque between the groups. However, the BCAA group showed a significantly higher extension peak torque at D3 (second isokinetic exercise), compared to the placebo group (p<.05). There was no difference in AST changes between the groups. Nonetheless, the CK and LDH were significantly reduced in the BCAA group, compared to the placebo group. There was no correlation between the extension peak torque and flexion peak torque. However, the CK and LDH increased proportionately in DOMS. Moreover, their concentrations significantly increased with a decreasing peak torque (p<.01). [Conclusion] An exercise-induced DOMS results in a decrease in the peak torque and a proportional increase in the CK and LDH concentrations. Moreover, the administration of BCAA inhibits the reduction of the extension peak torque and elevation of CK and LDH concentrations. Therefore, BCAA might be administered as a supplement to maintain the muscle strength and prevent muscle damage during vigorous exercises that may induce DOMS in sports settings.

• Genomics & Informatics
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• 제18권4호
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• pp.42.1-42.9
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• 2020

Chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-Seq) is a powerful technology to profile the location of proteins of interest on a whole-genome scale. To identify the enrichment location of proteins, many programs and algorithms have been proposed. However, none of the commonly used peak calling programs could accurately explain the binding features of target proteins detected by ChIP-Seq. Here, publicly available data on 12 histone modifications, including H3K4ac/me1/me2/me3, H3K9ac/me3, H3K27ac/me3, H3K36me3, H3K56ac, and H3K79me1/me2, generated from a human embryonic stem cell line (H1), were profiled with five peak callers (CisGenome, MACS1, MACS2, PeakSeq, and SISSRs). The performance of the peak calling programs was compared in terms of reproducibility between replicates, examination of enriched regions to variable sequencing depths, the specificity-to-noise signal, and sensitivity of peak prediction. There were no major differences among peak callers when analyzing point source histone modifications. The peak calling results from histone modifications with low fidelity, such as H3K4ac, H3K56ac, and H3K79me1/me2, showed low performance in all parameters, which indicates that their peak positions might not be located accurately. Our comparative results could provide a helpful guide to choose a suitable peak calling program for specific histone modifications.

• 전기학회논문지
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• 제61권9호
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• 한국자기공명학회논문지
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• 제3권2호
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• pp.140-148
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• 1999

Using 1H magnetic resonance spectroscopy (MRS), we quantitatively evaluated correlation representing linear relationship between the metabolite peak area ratios associated with poor shimming conditions. The inadequate shimming due to linear shim offsets directly affected overall MR spectral quality as well as peak area for each metabolite. Three major peaks such as N-acetylaspartate (NAA), creatine (Cr,) choline (Cho) were used as a reference for data analysis. Despite considerable variations of metabolite peak area, a significant correlation between the metabolite peak area ratios relative to Cr was established while the correlation between the peak area ratios relative to Cho and NAA was not. The present study suggested that metabolite peak area ratios based on the metabolite of Cr could be an acceptable quantification method even under the poor shimming in clinical MRS examination.

• 해양환경안전학회지
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• 제20권3호
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• pp.285-291
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• 2014

This study applied regression analysis to evaluate the impact of hourly average congestion calculated by bumper model in the congested area of each passage of each port on the peak time congestion, to suggest the model formula that can predict the peak time congestion. This study conducted regression analysis of hourly average congestion and peak time congestion based on the AIS survey study of 20 ports in Korea. As a result of analysis, it was found that the hourly average congestion has a significant impact on the peak time congestion and the prediction model formula was derived. This formula($C_p=4.457C_a+29.202$) can be used to calculate the peak time congestion based on the predicted hourly average congestion.

• 대한전기학회논문지:전력기술부문A
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• 제51권9호
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• pp.417-424
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• 2002

This paper presents an industrial peak load management system for the peak demand control. Kohonen neural network and wavelet transform based techniques are adopted for industrial peak load forecasting that will be used as input data of the peak demand control. Firstly, one year of historical load data of a steel company were sorted and clustered into several groups using Kohonen neural network and then wavelet transforms are applied with Biorthogonal 1.3 mother wavelet in order to forecast the peak load of one minute ahead. In addition, for the peak demand control, composite fuzzy model is proposed and implemented in this work. The results are compared with those of conventional model, fuzzy model and composite model, respectively. The outcome of the study clearly indicates that the composite fuzzy model approach can be used as an attractive and effective means of the peak demand control.