• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.173-190
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• 2019

Steel-confined reinforced concrete (SCRC) columns feature highly complex and invisible mechanisms that make damage evaluation and pattern recognition difficult. In the present article, the prevailing acoustic emission (AE) technique was applied to monitor and evaluate the damage process of steel-confined RC columns in a quasi-static test. AE energy-based indicators, such as index of damage and relax ratio, were proposed to trace the damage progress and quantitatively evaluate the damage state. The fuzzy C-means algorithm successfully discriminated the AE data of different patterns, validity analysis guaranteed cluster accuracy, and principal component analysis simplified the datasets. A detailed statistical investigation on typical AE features was conducted to relate the clustered AE signals to micro mechanisms and the observed damage patterns, and differences between steel-confined and unconfined RC columns were compared and illustrated.

• 한국건설순환자원학회논문집
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• 제2권2호
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• pp.93-100
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• 2006

Building materials are trending toward environmental materials nowadays and the market share of those is growing. So those researches and developments for environmental property are proceeding now. The main properties of environmental products are far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus, these products are used with shape of mortar, and spray on the finish material. But There are not much researches for the concrete, main material in construction field, with those functional properties. So in this research we evaluated slump, compressive strength and air content as basic properties for concrete using functional materials of sericite, wood pattern sand stone, carbon black and nanometric silver solution and functional properties like far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus. The results were as follows. The most useful material in the functional materials was carbon black. Sericite and nanometric silver solution had a little effect on functional property, so it was difficult to apply to concrete, and wood pattern sand stone had a high functional property but low compressive strength, can be applied to a factory product. Anti fungus of the concrete using nanometric silver solution was not clear but if those specimens were aged in $CO_2$ gas for a long time it might apparent.

• 한국분무공학회지
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• 제22권4호
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• pp.218-224
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• 2017

In order to improve the quality of air in urban areas, the emission regulations are being strengthened by the government. The on-road test of light-duty vehicles was started with PEMS because certification test mode does not sufficiently reflect on-road conditions. Therefore, The PEMS-based test was implemented from Sep. 2017 in Europe and Korea. However, this is lack of data on various on-road patterns in Korea. The purpose of the present study has analyzed the effect of speed per acceleration and acceleration on NOx emission on-road driving. The test route consisted of urban, rural, and motorway in Seoul. This study has been conducted by Euro-6 vehicles using on SCR system with PEMS. The on-road emission characteristics were evaluated by moving averaging windows (MAW) method. In results, RDE-NOx by severe driving pattern has been 1.4 times higher than soft driving pattern NIER Route 1.

• 소음진동
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• 제6권6호
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• pp.843-849
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• 1996

Locations and emission characteristics of noise source of motor vehicles are great important factors to control the road traffic noise in effective ways. From results of this study on emission characteristics of engine and exhaust noise, we could find that every noise emission of different kind of vehicles has smilar pattern. The main emission locations of engine noise for the front of vehicle became the space between the road surface and bottom of the body and radiator grill, and for the side of vehicle became the space between the road surface and bottom nearby the front wheel. In case of exhaust noise of passenger-car and light truck, all the highest sound intensity level located near surface of road. But it is hard to conclude the height of noise source of driving vehicles with only results of this study. So further studies are needed to check the emission characteristics of noise.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.262.2-262.2
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• 2014

Plasma processing is an essential process for pattern etching and thin film deposition in nanoscale semiconductor device fabrication. It is necessary to maintain plasma chamber in steady-state in production. In this study, we determined plasma chamber state with residual gas analysis with self-plasma optical emission spectroscopy. Residual gas monitoring of fluorocarbon plasma etching chamber was performed with self-plasma optical emission spectroscopy (SPOES) and various chemical elements was identified with a SPOES system which is composed of small inductive coupled plasma chamber for glow discharge and optical emission spectroscopy monitoring system for measuring optical emission. This work demonstrates that chamber state can be monitored with SPOES and this technique can potentially help maintenance in production lines.

• 한국분무공학회지
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• 제22권1호
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• pp.8-12
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• 2017

Recently, manufacture and sales of passenger car with GDI (Gasoline Direct injection) were dramatically increased in Korea. In this study, investigation on the exhaust emission characteristics of GDI vehicles according to mileage were conducted by using chassis dynamometer and emission analyzer. Test cars selected 5 types with G4FD engine (1600 cc) and emissions of total 14 vehicles analyzed. Measurement and evaluation on emissions (CO, NOx, NMOG, $CO_2$) characteristics of GDI vehicles with mileages from 40,000 to 80,000 km in certification driving cycle (CVS-75) were carried out in this study. It is revealed that emission results of all test cars shows below emission standard, NMOG emission value of about 80,000 km doubled that of 40,000 km and emission increased by accumulated mileage. Also, increasing pattern of NOx emissions shows when the vehicle mileages was increased and $CO_2$ emission increasing trend obviously do not show according to mileages.

• 대한전자공학회논문지SP
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• 제46권3호
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• pp.125-137
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• 2009

음향방출 기법은 작동중인 상태에서 기계 설비를 비파괴 검사할 수 있는 기법이며, 균열성장 같은 장애의 신뢰성 있는 감시를 위해서 순간적인 균열신호뿐만 아니라 동특성을 이용하는 것이 중요하다. 균열성장을 검출하기 위해 널리 사용되는 물리적 파괴 3단계는 음향방출 현상이 시간에 따라 서로 겹치는 문제점이 있어 정확한 균열성장 시간을 추정하기 어렵다. 제안한 패턴인식 기법은 오경보와 미탐지를 최소화하기 위해서 음향방출 동특성을 입력으로 사용하고, 균열성장 시간을 정확히 추정하기 위해 시간에 따른 클러스터링 기법을 사용한다. 실험결과는 제안한 패턴인식 기법이 압력의 변화에 의한 음향방출의 변화의 강인함 때문에 실용화에 효율적임을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.343-344
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• 2006

Consumption of fossil fuel has been increasing steadily, and it has seriously affected environment. Due to this situation, UN establish ed UNFCC (United rations Framework Convention on Climate Change), and since Feb. 2005, Kyoto Protocol has come into effect for UNFCC obligation. In Korean power system, coal and oil thermal generation emitting large CO2 form about 46% of total generation. Moreover since electricity dem and has been increasing continuously, various alternatives should be designed to comply with Kyoto Protocol. In this paper, we analyze changes of each GENCO's generation pattern and resource planning under CO2 emission constraints. For this analysis, we incorporate CO2 emission constraints and the emission trading mechanism into the conventional OPF model.

• 제어로봇시스템학회논문지
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• 제8권10호
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• pp.827-832
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• 2002

We propose a prediction method of the pollutant and a synchronous classification of the current state of SOx emission in the power plant. We use the auto-regressive with exogeneous (ARX) model as a predictor of SOx emission and use a radial basis function network (RBFN) as a pattem classifier. The ARX modeling scheme is implemented using recursive least squares (RLS) method to update the model parameters adaptively. The capability of SOx emission monitoring is utilized with the application of the RBFN classifier. Experimental results show that the ARX model can predict the SOx emission concentration well and ARX modeling parameters can be a good feature for the state monitoring. in addition, its validity has been verified through the power spectrum analysis. Consequently, the RBFN classifier in combination with ARX model is shown to be quite adequate for monitoring the state of SOx emission.

• 한국재료학회지
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• 제25권2호
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• pp.100-106
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• 2015

Plasma properties of dielectric barrier discharges (DBDs) at atmospheric pressure were measured and characterized using optical emission spectroscopy. Optical emissions were measured from argon, nitrogen, or air discharges generated at 5-9 kV using 20 kHz power supply. Emissions from nitrogen molecules were markedly measured, irrespective of discharge gases. The intensity of emission peaks was increased with applied voltage and electrode gap. The short wavelength peaks (315.9 nm and 337.1 nm) measured at the middle of DBDs were significantly increased with applied voltage. The optical emission from DBDs decreased with the addition of oxygen gas, which was especially significant in argon discharge. Emission from oxygen molecules cannot be measured from air discharge and argon discharge with 4.8% oxygen. The emission intensity at 337.1 nm and 357.7 nm related with nitrogen molecule was sensitively changed with electrode types and discharge voltages. However, the pattern of argon emission spectrum was nearly the same, irrespective of electrode type, oxygen content, and discharge voltage.