• 한국대기환경학회지
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• 제26권2호
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• pp.234-240
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• 2010

Gas flow uniformity is an important factor to guarantee particle removal performance of electrostatic precipitators (EP), and the gas flow uniformity is evaluated by a fraction of standard deviation to the mean of gas flow distribution (%RMS) or a technical standard, ICAC EP-7, provided by The Institute of Clean Air Companies. In this study, relationship between the ICAC EP-7 and %RMS in evaluation of gas flow uniformity was investigated in terms of flow velocity. The maximum values of %RMS for gas velocity distribution of normal distribution has been obtained, and the maximum values of %RMS with gas velocity distribution satisfying ICAC EP-7 standards were also evaluated. With gas flow distribution obtained from CFD analysis and physical model test of real EP, %RMS values were calculated and it was tested if those gas flow distribution satisfy the criteria specified in ICAC EP-7. The %RMS values satisfying criteria of ICAC have been appeared to have similar values with %RMS values calculated with normal distribution of gas velocities.

• 대한임베디드공학회논문지
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• 제12권2호
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• pp.79-88
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• 2017

One of the important applications of activity sensing in the home is energy monitoring. Many previous methodologies for detecting and recognizing household appliances have been proposed. This paper presents an approach that uses an energy metering circuit (EMC) to classify and identify the various electrical devices in home based on root-mean-square (RMS) consumed current value. EMC gathers the RMS current values created by appliance state transition (e.g., on to off) and apparatus operating process. In this paper, an identification algorithm is proposed to detect a change in current levels using the standard deviation of current signals and their average values. In addition, characteristic of the appliance is extracted concerning four feature parameters concerning the number of current levels, the minimum level, the maximum level, and signal-to-noise ratio (SNR) of them. Experiment results validate the reliable performance of the proposed identification method for 11 representative appliances.

• 대한지역사회영양학회지
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• 제22권4호
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• pp.279-288
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• 2017

Objectives: Recommended Menu (RM) prepared according to the Target Pattern expected to meet the dietary reference intake (DRI) of nutrients. Nutritional adequacy of RM in 'DRI for Koreans 2015' were analyzed to verify whether such expectation was fulfilled. Methods: Dishes in RM are categorized by 5 food groups, and number and types of dishes for main meal and between-meals were analyzed. The energy and 12 nutrients (protein, dietary fiber, Ca, P, Fe, Na, K, vitamin A, thiamin, riboflavin, niacin and vitamin C) contents in 10 RMs were calculated using the food composition table (CD) in 'DRI for Koreans'. Energy, energy contribution ratio, and nutrient contents in 10 RMs for 18 age groups were evaluated based on the 'DRI for Koreans 2015'. Results: Number of dishes per meal were 4.83, and representative table setting consisted of cooked rice + soup (or stew) +3 side dishes. Energy contents of RM were 75~109% of estimated energy requirement (EER). None of the RM met the DRI of all 12 nutrients examined. Calcium was the most insufficient nutrient. Only 1-2 years' RM met the DRI, all the other RMs did not meet the calcium DRI. Dietary fiber and potassium contents were also insufficient in most RM. In adult male's RM, only 1 nutrient, i.e. calcium did not meet the DRI, but in female adult's RM, 5~6 nutrients did not meet the DRI. Energy contribution ratio of carbohydrate, protein, and fat in RM were 59.0~70.4%, 15.7~17.5%, 12.1~23.5%, respectively. And 4 RMs out of 10 exceeded the upper limit of acceptable macro-nutrient distribution range (AMDR) of carbohydrate and 3 RMs out of 10 RM were below the lower limit of fat AMDR. Contribution ratio of nutrients were ${\geq}40%$ by food groups were as follows: grain group in energy and carbohydrate; meat fish egg legume group in fat, protein, and niacin; vegetables group in dietary fiber, vitamin A, and vitamin C; milk dairy products group in calcium. Conclusions: RM prepared according to the Target Pattern did not meet nutritional adequacy as expected. Especially calcium, potassium, and dietary fiber contents are needed to be increased in many RMs. Further, energy content in RM needs to be adjusted for fat sugar food group assigned in Target Pattern and condiment.

• 한국연소학회지
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• 제12권1호
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• pp.1-10
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• 2007

Analytical investigation of acoustic wave scattering from turbulent premixed flames was conducted to evaluate the acoustic energy amplification/damping. Such acoustic energy change is attributed to the acoustic velocity jump due to flame's heat release. Small perturbation method up to second order and stochastic analysis were utilized to formulate net acoustic energy and the energy transfer from coherent to incoherent energy. Randomly wrinkled flame surface is responsible for the energy transfer from coherent to incoherent field. Nondimensional parameters that govern net acoustic energy were determined: rms height and correlation length of flame front, incident wave frequency, incidence angle, and temperature ratio. The dependence of net acoustic energy upon these parameters is illustrated by numerical simulations in case of Gaussian statistics of flame front. Total net energy was amplified and the major factors that affect such energy amplification are incidence angle and temperature ratio. Coherent (incoherent) energy is damped (amplified) with rms height and correlation length of flame front.

• 한국환경과학회지
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• 제8권3호
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• pp.309-318
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• 1999

In order to fast predict the wind-driven current in a small bay, a convolution method in which the wind-driven current can be generated only wih the local wind is developed and applied in the Sachon Bay. The root mean square(rms) ratio defined as the ratio of the rms error to the rms speed is 0.37. The rms ratio is generally less than 0.2, except for all the mouths of Junju Bay and Namhae-do and in the region between Saryang Island and Sachon. The spatial average of the recover rate of kinetic energy(rrke) is 87%. Thus, the predicted wind-driven current by the convolution model is in a good agreement with the computed one by the numerical model. The raio of the difference between observed residual current (Vr) and predicted wind-driven current (Vc) to a residual current, that is, (Vr-Vc)/Vr shows 56%, 62% at 2 moorings in the Sachon Bay.

• 한방재활의학과학회지
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• 제24권1호
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• pp.83-92
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• 2014

Objectives To evaluate the clinical usefulness between muscle energy techniques (MET) and transcutaneous electrical nerve stimulator (TENS), we performed both on elector spinae muscle of acute low back pain patients. Methods After performing MET and TENS, we compared both in terms of electrical activity. We performed MET or TENS on elector spinae muscle of acute low back pain patients in each group (n=15,15). After performing MET or TENS, we analyzed root mean square (RMS), median edge frequency (MEF) and asymmetry index (AI). Results 1. After performing MET on elector spinae muscle of acute low back pain patients, RMS was significantly decreased compared with before (p<0.005). 2. After performing TENS on elector spinae muscle of acute low back pain patients, RMS was significantly decreased compared with before (p<0.005). 3. After performing MET on elector spinae muscle of acute low back pain patients, asymmetric index was significantly decreased compared with before (p<0.05). Conclusions According to above results, performing MET on elector spinae muscle of acute low back pain patients has effect in terms of RMS and asymmetric index. And performing TENS on elector spinae muscle of acute low back pain patients also has similar effect in terms of RMS but has not in terms of asymmetric index.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.663-665
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• 2003

A field spectroradiometer SE-590 was used to measure the spectral reflectance of water body. The reflectance was calculated as the ratio of surface water radiance to the standard whiteboard radiance nearly measured at the same time. Water samples were taken simultaneously for determining their chlorophyll-a, suspended solid (SS) and transparency. The relationships between those water quality parameters and spectral reflectance were analy zed using stepwise multiple regression to derive optimal prediction models . The multiple regression was also applied to the SE-590 simulated SPOT bands. The SPOT image of the same day was also analyzed using the same method to compare the statistical results. It showed that the multiple regression models using the SE-590 reflectance data got the best water quality prediction results. The evaluated RMS error of chlorophyll-a, SS and transparency of water quality parameters were 0.57 ug/l, 0.2 mg/l and 0.17 m, respectively, and the RMS errors were 0.36 ug/l, 0.49 mg/l and 0.42 m for SPOT data, respectively. The SE-590 simulated SPOT three bands data obtained the worst results and the RMS errors were 1.77 ug/l, 0.49 mg/l and 0.37 m, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1291-1295
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• 2004

This paper proposed a new approach for endpoint detection of isolated speech, which proves to significantly improve the endpoint detection performance. The proposed algorithm relies on the root mean square energy (rms energy), zero crossing rate and spectral characteristics of the speech signal where the Euclidean distance measure is adopted using cepstral coefficients to accurately detect the endpoint of isolated speech. The algorithm offers better performance than traditional energy-based algorithm. The vocabulary for the experiment includes English digit from one to nine. These experimental results were conducted by 360 utterances from a male speaker. Experimental results show that the accuracy of the algorithm is quite acceptable. Moreover, the computation overload of this algorithm is low since the cepstral coefficients parameters will be used in feature extraction later of speech recognition procedure.

• 한국지진공학회논문집
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• 제7권1호
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• pp.31-40
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• 2003

지진응답 해석 시 불확실한 지진현상을 추정하여 설계지진파를 선정하는 것은 어려운 일 중의 하나이다. 게다가 제한된 숫자의 설계인자에 상응하는 지진파가 결코 유일하지 않다는 문제도 있다. 따라서 동일한 설계진도에 상응하는 여러 지진파들로부터 구한 응답치들이 서로 크게 차이가 날 수 있다. 본 논문은 이 같은 지진하중의 불확실성을 체계적으로 고려하는 실용적인 지진파 생성 기법을 제시한다. 이 기법은 에너지 개념의 RMS 지진가속도에 기반하며 주요 지진파 설계인자의 불확실성을 고려한다. 시뮬레이션을 통해, 이 새로운 RMS 기법이 지진재해에 상응하는 지진파를 대량 생성하는 경우에 적합하며 따라서 소량의 지진파 생성에 적합한 기존의 방법들과 비교할 때 특히 확률론적 지진응답 해석 시 유용하다는 점을 확인하였다.

• 에너지공학
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• 제23권3호
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• pp.51-57
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• 2014

MILD 연소는 고온의 배기가스가 연소로 내에 유입되는 연료와 공기의 혼합물과 고온의 배기가스 가 만나는 위치에 따라 질소산화물 저감 특성이 많은 영향을 받는다. 본 연구에서는 폐기물소각로에 적용한 MILD 연소로에서 배기가스 재순환 여부에 따른 유동 특성과 배기가스 재순환 위치에 따른 유동 특성을 살펴보아 최적의 배기가스 재순환 위치를 선정하는 것을 목적으로 하였다. 본 연구의 전산 해석의 결과는 배기가스 재순환이 없는 경우에는 수직 격벽 상부의 단면에서 속도 분포는 수직 격벽 바로 상부에 큰 속도가 있고 더 상부는 역류가 일어나는 것을 확인할 수 있었다. 배기가스 재순환이 있는 경우는 상부 자유공간에서의 유동 균일도를 수직 격벽 상부 단면에서의 x 방향 속도의 %RMS 값으로 비교하였으며 재순환 흡입구 위치가 자유공간 우측 상단에 위치한 경우가 %RMS 값이 57.4%로 가장 작은 값을 가지며 따라서 가장 효과적임을 알 수 있었다.