• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.717-724
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• 2002

To investigate the behavior of air-shaft and existing tunnel by excavating the small-diameter shaft into the existing tunnel, prototype air-shaft was constructed and analyzed in this study. Geotechnical characterization was conducted by boring and rock cores obtained were tested in the laboratory. Field monitoring including radial and tangential stresses and displacements was conducted with the 3-dimensional numerical analysis of prototype air-shaft. Results of field monitoring were compared with the numerical results. The results showed that maximum displacement of 2.11mm and maximum tangential stress of 54.0 kg/$\textrm{cm}^2$ were obtained during shaft excavation near the right shoulder of the existing tunnel. The comparison of these field measurements with 3-dimensional numerical analysis showed that much more higher stress was measured during excavation compared to the numerical results even though the trends of stress and displacement were similar.

• 한국정밀공학회지
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• 제12권9호
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• pp.66-73
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• 1995

This paper presents monitoring and control system to decrease non-production time such as air grinding and partial contact in cylindrical plunge grindings. The 4-stage model of the plunge grinding process is proposed according to the state of contact between grinding wheel and workpiece; air grinding, partial contact, entire contact and spark out. Experimentally it is seen that the AE sensor and ultrasonic sensor are very effective to detect the grinding states. Monitoring and control algorithm using recognized grinding process was introduced and a experiment were conducted to verify the developed system.

• 한국대기환경학회지
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• 제29권4호
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• pp.407-438
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• 2013

Current status and future direction of air quality modeling for monitoring and forecasting air quality in East Asia were discussed in this paper. An integrated air quality modeling system, combining (1) emission processing and modeling, (2) meteorological model simulation, (3) chemistry-transport model (CTM) simulation, (4) ground-based and satellite-retrieved observations, and (5) data assimilation, was introduced. Also, the strategies for future development of the integrated air quality modeling system in East Asia was discussed in this paper. In particular, it was emphasized that the successful use and development of the air quality modeling system should depend on the active applications of the data sets from incumbent and upcoming LEO/GEO (Low Earth Orbit/Geostationary Earth Orbit) satellites. This is particularly true, since Korea government successfully launched Geostationary Ocean Color Imager (GOCI) in June, 2010 and has another plan to launch Geostationary Environmental Monitoring Spectrometer (GEMS) in 2018, in order to monitor the air quality and emissions in/around the Korean peninsula as well as over East Asia.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2005년도 추계학술대회 논문집
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• pp.308-309
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• 2005

• 항공우주정책ㆍ법학회지
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• 제6권
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• pp.345-365
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• 1994

• 한국방재학회지
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• 제6권3호
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• pp.42-49
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• 2006

• 한국대기환경학회지
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• 제10권4호
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• pp.245-251
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• 1994

We considered that characteristics of SO$_2$, concentration level and relations of the meteorological parameters and high pollution concentration from the data measured 7 air quality continuous monitoring stations during 4 years, from 1990 to 1993 in Pusan. The SO$_2$ concentration level showed decreasing trend yearly, it was maximum in Winter, minimum in Summer. The time of SO$_2$ peak concentration lagged from seashore to land because of break-down of the nocturnal inversion layer and seabreeze. Ihe correlations of daily SO$_2$, value between various air quality continuous monitoring stations were highest between Beomcheondong and Meongryundong, lowest between Daeyeondong and Sinpyeongdong because of difference of air Pollution emission sources characteristic. The meteorological parameters affecting SO$_2$ concentration level were minimum temperature, relative humidity, wind speed and air pressure. The SO$_2$ high pollution($\geq$95ppb) occurred almost in Winter, particulaly in such day showing lower wind speed and higher air pressure. Elementary SO$_2$ high Pollution Predictor were high pressure system and stability of lower atmosphere.

• 한국가시화정보학회지
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• 제18권1호
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• pp.11-17
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• 2020

The reduction of CO2 emissions has been a key target in the marine industry since the IMO's MEPC published its findings in 2009. Air lubrication method is one of the mature technologies for commercialization to reduce the frictional resistance and enhance fuel efficiency of ships. Since the air lubrication pattern varies according to the ship's standing position and injection flow rate, in order to effectively control the air lubrication system, it is necessary to be able to judge the air layer development state based on the information collected from the monitoring sensor. In this study, we performed the air lubrication ship simulation experiment to measure the void fraction and the frictional resistance. The void fraction was measured to confirm the behavior of the air. Through the measurement of the frictional resistance, the change in frictional resistance reduction rate from the injection point to the longitudinal direction of the ship was confirmed. Based on the measurement results, correlation analysis was performed on void fraction and frictional resistance reduction rate.

• 한국환경과학회지
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• 제26권8호
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• pp.927-938
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• 2017

This study was conducted to determine correlations and similarity between the ozone and $PM_{10}$ data of 19 air quality monitoring stations in Busan from 2013 to 2016, using correlation and cluster analyses. Ozone concentrations ranged from $0.0278{\pm}0.0148ppm$ at Gwangbok to $0.0378{\pm}0.017ppm$ at Taejongdae and were high in suburban areas, such as Yongsuri and Gijang, as well as in coastal areas, such as Jaw, Gwangan, Taejongdae and Noksan. $PM_{10}$ concentrations ranged from $37.2{\pm}25.0ug/m^3$ at Gijang to $58.3{\pm}32.2ug/m^3$ at and Jangrim. $PM_{10}$ concentrations were high in the west, exceeding the annual ambient air quality standard of $50ug/m^3$. Positive correlations were observed for ozone at most stations, ranging from 0.61 between Taejongdae and Sujeong to 0.92 between Bugok and Myeongjang. The correlation coefficients of $PM_{10}$ between stations ranged from 0.62 between Jangrim and Jaw to 0.9 between Gwangbok and Sujeong. Yeonsan, Daeyeon, and Myeongjang were highly correlated with other stations, so they needed to be reviewed for redundancy. Ozone monitoring stations were initially divided into two sections, north-western areas and suburban-coastal areas. The suburban-coastal areas were subsequently divided into three sections. $PM_{10}$ monitoring stations were initially divided into western and remaining areas, and then the remaining areas were subsequently divided into three sections.

• 한국대기환경학회지
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• 제27권6호
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• pp.734-745
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• 2011

In this article, we reviewed the monitoring status of hazardous VOC in ambinet air in Korea and some developed countries such as USA, Japan, and UK. In many countries, two types of VOC monitoring stations are being operated, i.e., for hazardous VOC and photochemical VOC. Each country has different target VOC but all includes benzene. Korea, Japan, and UK have a national ambient air quality standard for benzene, but no national standard has been established in the USA. For sampling of the hazardous VOC, the adsorbent method is adopted in Korea and UK, while the canister method is used in the USA. Both of adsorbent and canister methods are used in Japan. USA and UK have only non-automatic method to measure the hazardous VOC, and the individual samples are being sent to their national laboratories for integrated analysis. On the other hand, Korea and Japan have automatic and nonautomatic methods to measure the hazardous VOC. Local governments or regional environmental agencies in Korea and Japan have the authorization for the sampling and analysis of VOC. According to a field study to evaluate the performance of automatic VOC monitoring system, controlling the moisture in the air sample was identified as the most important problem. However, careful attention must be given to using a moisture removing device such as Nafyon dryer, because of unexpected artifacts formation. In order to have reliable data, it is highly recommended not only to use internal standards, but to use appropriate hydrophobic adsorbents as a cold trap in any automatic on-line VOC monitoring system.