• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.1402-1406
• /
• 2004

As a method of confirming light flickering, we tried to confirm the flicker index measured by Flickermeter and the application possibility by using digital intensity of illumination meter. Also, after simulating the quality deterioration of electric power and generating a various voltage change, we studied on the function between the flicker index measured by Flickermeter and the flicker index for the intensity of illumination by using digital intensity of illumination meter.

• 생명과학회지
• /
• 제22권8호
• /
• pp.1077-1084
• /
• 2012

아로마 향기요법에서 마조람(Origanum majorana)향이 여성의 뇌기능에 미치는 효능을 살펴보기 위해 뇌파 변화를 살펴보았다. 본 연구에서는 신체적으로 건강한 20대 여자 성인(29명)을 대상으로 검증된 수면장애 조사를 통하여 수면질을 조사하여 수면에 문제를 가진 대상자를 선별하고 마조람 향기요법을 실행하여 뇌파의 변화를 분석하였다. 10-20 국제법에 의하여 전두부, 측두부, 후두부, 두정부에 뇌파 전극을 부착하였다. 마조람(50 ${\mu}l$)를 사용하여 향기요법 전 3분, 향기요법 중 3분, 그리고 향기요법 후 3분씩 나누어서 뇌파 검사를 시행하였다. 결과에서 수면질이 좋은 여자에게 마조람향이 뇌파에 미치는 영향은 양쪽 대뇌반구의 측두부, 좌측 전두부와 두정부, 우측 전두부와 후두부에서 세타파를 증가시키고, 좌측 후두부에서 알파파를 감소시키며, 우측 측두부에서 베타파를 감소시켰다. 또한 수면질이 나쁜 여자에게 있어서 양쪽 대뇌반구의 측두부와 우측 전두부에서 세타파가 증가되었으며, 알파파가 좌측 두정부에서 감소되었다. 결론적으로 마조람 에센셜 향기요법은 수면질이 좋은 여자에게 알파파와 베타파를 감소시킴으로써, 수면질이 나쁜 여자에게는 알파파 감소를 통하여 각성 상태에서 벗어나게하고, 수면질이 좋은 사람뿐만 아니라 수면질이 나쁜 사람에게도 세타파의 증가를 통하여 수면을 유도하는 긍정적인 뇌기능 효능이 있었다.

• Journal of Power Electronics
• /
• 제17권4호
• /
• pp.914-922
• /
• 2017

Multilevel converters have attracted a lot of attention in recent years. The efficiency parameters of a multilevel converter such as the switching losses and total harmonic distortion (THD) mainly depend on the modulation strategy used to control the converter. Among all of the modulation techniques, the selective harmonic elimination (SHE) method is particularly suitable for high-power applications due to its low switching frequency and high quality output voltage. This paper proposes a new expression for the SHE problem in five-level converters. Based on this new expression, a simple analytical method is introduced to determine the feasible modulation index intervals and to calculate the exact value of the switching angles. For each selected harmonic, this method presents three-level or five-level waveforms according to the value of the modulation index. Furthermore, a flowchart is proposed for the real-time implementation of this analytical method, which can be performed by a simple processor and without the need of any lookup table. The performance of the proposed algorithm is evaluated with several simulation and experimental results for a single phase five-level diode-clamped inverter.

• 환경생물
• /
• 제37권2호
• /
• pp.204-216
• /
• 2019

수생태계 생물학적 온전성을 평가하기 위하여 국내 하천 및 하구 923개 지점의 자료를 근거로 한국형 다중형 돌말지수(KMDI)를 개발하고, 이를 금강수계 233개 지점을 대상으로 온전성평가를 실시하여 단일형 돌말지수들과 비교 검토하였다. KMDI의 개발은 1) 먼저 선행문헌들을 참고로 300개 이상의 메트릭을 추출하고, 2) 이 중 설명력이 높은 46개 후보 메트릭을 선택하며, 3) 각 메트릭 값들의 변이성, 중복성, 변별력, 환경에 대한 민감성 등을 검증하고, 최종적으로 5가지의 메트릭을 선정하였다. KMDI는 매트릭의 단순합으로 표현하고, 환경요인들에 대한 신뢰성 검토 결과, 토지이용, BOD, TN, 전기전도도 등에 대해 높은 민감성 및 설명력을 보였으나 단일형 돌말지수들 보다는 동일 지점의 생물학적 온전성은 다소 높게 평가되는 특성을 보였다. 추후 국내는 물론 지역에 상관없이 적용가능한 설명력 높은 매트릭의 발굴 및 정확한 돌말류 분석 연구가 뒷따라야 될 것으로 판단되었다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.634-637
• /
• 2007

A weighted sound pressure level has been used to evaluate sounds test or sound quality test for a refrigerator up to present but the customer had different satisfactions of refrigerator sounds with different listening position. It means that there was a sound directivity caused by a position of fan or compressor. In this paper, we proposed a sound power spectrum guideline that represents total sound of refrigerator.

• Journal of Power Electronics
• /
• 제18권6호
• /
• pp.1650-1658
• /
• 2018

Multilevel converters are being widely used in medium-voltage high-power applications including motor drive systems, utility power transmission, and distribution systems. Selective harmonic elimination (SHE) is a well-known modulation method to generate high quality output voltage waveforms. This paper presents a new simple practical method for generating a generalized five-level waveform without selected low order harmonics. This method is based on a phase-shifted expression for the SHE problem, which can analytically calculate the exact values of switching angles and the feasible modulation index range for three-level and five-level waveforms. The proposed method automatically determines the number of transitions between levels and generates proper output waveform without solving complex trigonometric equations. Due to the simplicity of the computational burden, the real-time implementation of the proposed algorithm can be performed by a simple processor. Simulation and experiment results verify the correctness and effectiveness of the proposed method.

• Current Applied Physics
• /
• 제18권11호
• /
• pp.1436-1440
• /
• 2018

SiN and SiCN film production using plasma-enhanced atomic layer deposition (PE-ALD) is investigated in this study. A developed high-power and high-density multiple inductively coupled plasma (multi-ICP) source is used for a low temperature PE-ALD process. High plasma density and good uniformity are obtained by high power $N_2$ plasma discharge. Silicon nitride films are deposited on a 300-mm wafer using the PE-ALD method at low temperature. To analyze the quality of the SiN and SiCN films, the wet etch rate, refractive index, and growth rate of the thin films are measured. Experiments are performed by changing the applied power and the process temperature ($300-500^{\circ}C$).

• 한국환경과학회지
• /
• 제11권3호
• /
• pp.201-207
• /
• 2002

This study was carried out to evaluate the artificial neural network algorithm for water quality forecasting in Chungju lake, north Chungcheong province. Multi-layer perceptron(MLP) was used to train artificial neural networks. MLP was composed of one input layer, two hidden layers and one output layer. Transfer functions of the hidden layer were sigmoid and linear function. The number of node in the hidden layer was decided by trial and error method. It showed that appropriate node number in the hidden layer is 10 for pH training, 15 for DO and BOD, respectively. Reliability index was used to verify for the forecasting power. Considering some outlying data, artificial neural network fitted well between actual water quality data and computed data by artificial neural networks.

• 대한지역사회영양학회지
• /
• 제15권5호
• /
• pp.614-624
• /
• 2010

The purpose of this study was to investigate the effect of 3-month nutrition education (First Time Intervention, FI) + additional 3-month nutrition education (Repeated Intervention, RI) which was performed after the 8-month followup. FI was conducted during 0-3 months and RI for 11-14 months. Ninety-two subjects completed FI program, and 38 out of 92 subjects who received FI finished the RI. Anthropometric data, dietary assessment (24hr recall) and fasting blood analysis were measured at 0 month, 3 months, 11 months and 14 months time points. After FI (3 mo), waist circumference, triglycerides, total cholesterol were significantly decreased. At 11 month follow-up, body weight, BMI, hip circumference, SBP, DBP were significantly rebounced and HDL cholesterol was significantly decreased. Therefore, the effect of short-term nutrition education was not being sustained. After the secondary nutrition intervention (14 mo), waist circumference and hip circumference were again significantly decreased. Total diet quality index-international (DQI-I) score was significantly increased in both FI group and RI group. The changes in DQI-I scores were significantly correlated with the changes in body weight (r = -0.129, p < 0.05) and counts of nutrition education (r = 0.159, p < 0.05), indicating that effective nutrition education helps improve the diet quality leading to a possible role in CVD prevention among male workers. Although a short-term intervention seems to be a success, the effect was not retained in this study. Therefore, we suggest incorporating nutrition education as a routine program for male worker at worksite.

• 사상체질의학회지
• /
• 제32권1호
• /
• pp.39-49
• /
• 2020

The purpose of this study was to find out how sleep characteristics by Sasang constitution (SC) appear in Vietnamese immigrant women in Korea, and how sleep aberration by SC affected the quality of life. The number of 217 Vietnamese immigrant women joined this study. We surveyed SC with Korea Sasang Constitutional Diagnostic Questionnaire (KS-15) and sleep characteristics with Pittsburgh Sleep Quality Index(PSQI) questionnaire. We evaluated quality of life(QoL) with Euro Quality of Life-5Dimension(EQ 5D) questionnaire. A Chi-square test and a one-way ANOVA test were conducted according to SC, and T test also used to compare PSQI groups. Significant p was .05. The number(rate) of Taeeumin(TE), Soeumin(SE), and Soyangin(SY) were 40(18.4%), 55(25.3%), and 122(56.2%) respectively. The distribution of obstructive factors of sleep were significantly different according to SC(Too Cold in Sleeping, x =13.378, p=.037, Too Hot in Sleeping x²=12.834, p=.046). The distribution of daytime drowsiness(x²=15.379, p=.018) and falling concentration power (x²=17.533, p=.008) was significantly different according to SC. The sleep status of the subjects showed a significant negative correlation with the EQ 5D Visual Analogue Scale(VAS) (r =-.399, p<.001), and the EQ 5D Index (r=-.211, p=.002). In the EQ VAS, TE showed a difference between the good and bad sleeping groups (t=3.955, p<.001). SE showed a difference between the two groups in the EQ 5D Index (t=2.332, p=.037). SY did not show a difference between the two groups. This study reveals that sleeping is closely related with QoL and distribution of obstructive factors of sleep may be different according to SC. Further study to confirm the constitutional difference in race at Vietnam is needed.