• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.732-733
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• 2015

Currently, since the total energy amount has been increased continuously, the effort for energy efficiency of apartment building is necessary. Although the previous studies have been focused on the issue. Almost studies are about the simulation by applying the energy analysis tools and a lack of studies have been conducted the data analysis about real city gas amount of apartment building. Therefore, the objective of this study is to analyze the city gas consumption difference according to the exclusive dwelling in apartment building. To address this issue, the descriptive, correlation, analysis of variance (ANOVA) statistics are used in this study. As a result, in the case of annual total amount, the city gas is increased as the size of the exclusive dwelling area is increased. In the future, the findings of this study can be used as a basic material to develop the prediction model of city gas in apartment building.

• 조명전기설비학회논문지
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• 제14권2호
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• pp.26-30
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• 2000

본 논문에서는 실험데이터를 이용해서 가스터빈 제어시스템의 수학적인 모델링을 구하였다. 제어대상은 군산 화력발전소에 설치되어 었는 가스터빈을 모델로 선정하였고 터빈의 정격속도에서 계통병입 및 전부하까지의 운전구간에 국한하여 모델링올 구현하였다. 모델링은 최소자승 알고리즘을 이용하였으며 플랜트는 2차 시스템이라 가정하였고 망각지수는 0.98, 그리고 입.출력신호의 주기는 1sec로 선택하였다. 시뮬레이션 결과, 실제 시스템과 모델링에 의한 입.출력특성이 일치한디는 것을 알 수 있었다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권3호
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• pp.107-115
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• 2002

This parer presents the analysis of hot gas flow in puffer-type circuit breakers using FVFLIC method. For the analysis of arc-flow interaction, the flow field is analyzed from the equations of conservation for mass, momentum and energy with the assumption of local thermodynamic equilibrium state. The arc is represented as the energy source term composed of ohmic heating and radiation term in the energy conservation equation. Ohmic heating is computed by the electric field analysis only within the conducting plasma region. An approximate radiation transport model is employed for the evaluation of emission and absorption of the radiation. The analysis method was applied to the real circuit breaker model and simulation results such as pressure rise and arc voltage were compared with the experimental ones.

• Journal of Mechanical Science and Technology
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• 제15권6호
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• pp.752-763
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• 2001

Although there are many different solution schemes proposed for multidimensional radiative transfer, reference solutions to benchmark these methods are very rare in the literature. In this paper we produced some accurate solutions for purely absorbing gray and nongray gases including H$_2$O and CO$_2$by using the discrete transfer method with sufficiently accurate T(sub)95 quadrature set. The spectral transmittances of the mixtures of H$_2$O and CO$_2$are estimated by using the narrow band model. The gray gas solutions are obtained for different absorption coefficients, and the nongray real gas solutions are obtained for different mixture fractions of H$_2$O and CO$_2$. The numerical solutions presented in this paper are proved to be sufficiently accurate as compared to the available exact solutions and they may be used as reference solutions in evaluating various solution schemes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.191-196
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• 1993

Since the welding process is complex and highly nonlinear, it is very difficult to accurately model the process for real-time control. In this paper, a discrete-time transfer function matrix model for gas metal arc welding process is proposed. Although this linearized model is valid only around the operating point of interest, the adaptation mechanism employed in the control system render this model useful over a wide operating range. A multivariable one-step-ahead adaptive control strategy combined with a recursive least-squares method for on-line parameter estimation is implemented in order to achieve the desired weld bead geometries. Command following and disturbance rejection properties of the adaptive control system for both SISO and MIMO cases are investigated by simulation and experiment.

• 한국산업융합학회 논문집
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• 제24권3호
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• pp.323-331
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• 2021

With global warming and pollution problems, accurate forecasting of the harmful gases would be an essential alarm in our life. In this paper, we forecast the emission of the five gases(SOx, NO₂, NH₃, H₂S, CH₄) using the time series model of ARIMA, the learning algorithms of Random forest, and LSTM. We find that the gas emission data depends on the short-term memory and behaves like a random walk. As a result, we compare the RMSE, MAE, and MAPE as the measure of the prediction performance under the same conditions given to three models. We find that ARIMA forecasts the gas emissions more precisely than the other two learning-based methods. Besides, the ARIMA model is more suitable for the real-time forecasts of gas emissions because it is faster for modeling than the two learning algorithms.

• 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.

• 한국분무공학회지
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• 제22권2호
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• pp.47-54
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• 2017

$CO_2$ emission regulation will be prescribed and main issue in automotive industry. Mostly, vehicle's fuel efficiency deeply related to $CO_2$ emission is regulated by qualified driving test cycle by using chassis dynamometer and exhaust gas analyser. But, real driving fuel consumption rate depends so much on the individual usage profile and where it is being driven: city traffic, road conditions. In this study, vehicle model of fuel consumption rate for ICEV and PHEV was developed through co-simulation with CRUISE model and Simulink based on driving control model. The simulation results of fuel consumption rate were analysed with on-road vehicle data and compared with its official level.

• 한국전자거래학회지
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• 제23권2호
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• pp.33-47
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• 2018

도시가스 배관은 지중에 매설되어 있기 때문에 세부 관리가 어렵고 다양한 위험에 노출되어 있다. 본 연구에서는 도시가스 배관압력 실시간 데이터를 분석해 배관압력 이상을 예측하고 전문가의 의사결정을 돕는 모델을 제안한다. 국내 도시가스 공급업체들 중 하나인 중부도시가스사의 정압기에서 수집하는 실시간 배관압력 데이터와 시간변수, 외부환경변수를 통합해 분석 데이터로 사용한다. 아산시와 천안시에 위치하는 11개 정압기를 분석 대상으로 하며 분 단위 배관압력 예측모델을 구현한다. Random forest, support vector regression(SVR), long-short term memory(LSTM) 알고리즘을 사용해 회귀모델을 구현한 결과 LSTM 모델에서 우수한 성능을 보인다. 아산시 배관압력 예측모델의 경우 LSTM 모델에서 RMSE가 0.011, MAPE가 0.494이며, 천안시 배관압력 예측모델의 경우 LSTM 모델에서 평균제곱근오차(root mean square error, RMSE)가 0.015, 절대평균백분율오차(mean absolute percentage error, MAPE)가 0.668로 가장 낮은 오류율을 보인다.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권12호
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• pp.667-674
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• 2000

In this paper, a modified real-valued genetic algorithm is developed by using the meiosis for human's chromosome. Unlike common crossover methods adapted in the conventional genetic algorithms, our suggested modified real-valued genetic algorithm makes gametes by conducting the meiosis for individuals composed of chromosomes, and then generates a new individual through crossovers among those. Ultimately, when appling it for the gas data of Box-Jenkin, model and parameter identifications can be concurrently done to construct the optimal model of a neural network in terms of minimizing with the structure and the error.