• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.321-327
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• 2003

[ $CO_2$ ] sequestration in oil reservoirs can be one of the most effective strategies for long-term removal of greenhouse gas from atmosphere. This paper presents an advantage of the localized nonlinear approximation of integral equation solutions for inverting crosswell electromagnetic data, which are observed as a part of pilot project of $CO_2$ flooding at the Lost Hills oil field in central California, U.S.A. To monitor the migration of $CO_2$, we have used 2-D cylindrically symmetric and 2.5-D tomographic inversion methods. These two schemes produce nearly the same images if the borehole separation is large compared with the skin depth. However, since the borehole separation is much less than five skin depths in this $CO_2$ injection experiment, the 2.5-D model seems to be more reliable than the 2-D model. In fact, the pre-injection 2.5-D image is more successfully compared with induction logs observed in the two wells than the 2-D model. From the time-lapse crosswell imaging, we can confirm the replacement of brine with $CO_2$ makes a decrease of conductivity.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.1-8
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• 2016

In this study, we investigated the applicability of a short-term carbon dioxide ($CO_2$) passive sampler using turbidity change in a solution containing barium hydroxide ($Ba(OH)_2$). The mass of $CO_2$ introduced into the $Ba(OH)_2$ aqueous solution was strongly correlated ($r^2=0.9565$) to the change in turbidity caused by its reaction with the solution. The sampling rates calculated for 1 h and 24 h were $42.4{\pm}5.4mL\;min^{-1}$ and $2.3{\pm}0.3mL\;min^{-1}$, respectively. Both unexposed (blank) and exposed samplers remained stable during the storage period of at least two weeks. The detection limits of the passive sampler for $CO_2$ were 81.5 ppm for 1 h and 61.5 ppm for 24 h. Based on the results, the passive sampler using the change of turbidity in the $Ba(OH)_2$ aqueous solution appears to be a suitable tool for measuring short-term atmospheric concentrations of $CO_2$.

• Laser Solutions
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• v.5 no.3
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• pp.21-30
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• 2002

In automotive industry, the studies about light weight vehicle and improving the productivity have been accomplished. For that, TRIP steel was developed and research for the laser welding process have been performed. In this study, the monitoring system using photodiode was developed for laser welding process of TRIP steel. With measuring light, neural network model for estimating bead width and tensile strength was made and weld quality classification algorithm was formulated with fuzzy inference method.

• Journal of Welding and Joining
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• v.32 no.1
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• pp.102-107
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• 2014

SCR(Thyristor) type $CO_2$ welders have widely used for the welding process of heavy industries such as shipbuilding and plant. Since the industrial fields of shipbuilding and plant are usually exposed to severe welding condition with lots of dust, extreme temperature, high humidity and vibration, it is not recommended to use inverter type welder despite its state-of-the-art technology. Many sophisticated functions in the inverter welder may not work due to malfunction of its sensitive components. Hence this study focused on digitalization of SCR $CO_2$ welder by making use of microprocessor for SCR phase control. By this application, fine control of output of the $CO_2$ welding systems is achieved. Also pulse output mode of operation is realized and its verification is carried out with aluminum sample welding. The experimental results showed sound weld bead. The front operation panel provide user with numerical parameter settings and monitors. It will help precise weld process monitoring and control with digital value.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.269-271
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• 1999

온실기체농도에 대한 감시는 전세계적으로 미국의 NOAA(National Oceanic and Atmospheric Administration)/CMDL(Climate Monitoring and Diagnostic Laboratories)의 관측망을 비롯하여 세계기상기구(WMO)의 지구대기감시(GAW)계획에 의하여 수행되고 있다(Keeling et al., 1976 ; Komhyr et al., 1989). 기상청에서는 온실기체의 관측을 위하여 1994년에 전남 무안의 무안기상대에 비분산적외선 이와 같이 측정된 $CO_2$농도자료가 배경대기관측자료로써의 신뢰를 받기 위해서는 적절한 질관리를 통하여 인간 및 생물의 활동에 의한 직접적인 영향 제거하여야 한다.(중략)

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.153-161
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• 2008

The guidelines for indoor air quality of public transportations such as subway, train and bus was presented by Korean Ministry of Environment last end of year 2006 based on the great consequence of indoor air quality in daily life. Two main parameters, carbon dioxide($CO_2$) and particulate matters smaller than $10\;{\mu}m(PM_{10})$, were selected as index pollutants for the management of indoor air quality. The former pollutant, $CO_2$, is regarded as index of ventilation status and the major source of $CO_2$ in the train or subway is the exhalation of passengers. It is publically perceived that the high $CO_2$ concentration in a crowded subway will be reduced and ventilated with outdoor air by door-opening taken every 2 or 3 minutes when the train stops each station. However, there has not been any scientific proof and quantitative information on the effect of door-opening on the $CO_2$ reduction by ventilation with outdoor air. In this study, $CO_2$ concentration and number of passengers were measured at each station on the 3 lines of Korail metropolitan subway. In order to evaluate the effect of $CO_2$ reduction by door opening, the theoretical approach using the $CO_2$ balance equation was performed. By comparing the predicted data with monitoring one, the optimum $CO_2$ dilution factor was determined. For the first time, it was quantified that about 35% of $CO_2$ concentration in the subway indoor was removed by the door-opening at each station.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.157-162
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• 2011

This study is about implementing wireless transferring system in pre-hospital cardiopulmonary resuscitation(CPR). Also, this study includes monitoring based feedback between patient and hospital to increase the survival rate of emergency patient by developing the performance of cardiopulmonary resuscitation in pre-hospital. It minimizes the loss of flow rate or gastric inflation through the space between the airway and the esophagus, which enables the inspiration-expiration rate to be measured more precisely. Due to these reasons this study applied ET insertion based respiratory sensor to measure flow rate. The main indices of artificial ventilation are justified from minute respiration(V), end-tidal $CO_2(E_TCO_2)$, and tracheal pressure($P_{tr}$). The simulation is performed to verify the bandwidth and delay time of transport network for in-hospital monitoring even as transporting images and voice information simultaneously. The total bandwidth is 815 kbps, and WLAN (IEEE 802.11x) is used as communication protocol. The network load is under 1.5% and the transmit delay time is measured under 0.3 seconds.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.60-66
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• 2011

The$PM_{10}$ concentrations in the underground should be monitored for the health of commuters on the subway system. Seoul Metro and Seoul Metropolitan Rapid Transit Corporation are measuring several air pollutants regularly. In this paper, the reliability of the instruments using light scattering method is improved with the help of a linear regression analysis technique to measure the $PM_{10}$ concentrations continuously in the subway stations. In addition, an USN monitoring system is implemented to display and record the data of $PM_{10}$, CO/$CO_2$, humidity, and temperature. To transmit and receive these measured sensor data, 2.4GHz Zigbee, 424MHz wireless communication, and CDMA M2M method are applied and evaluated.

• Journal of the Korean earth science society
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• v.30 no.5
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• pp.588-597
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• 2009

Measurements of atmospheric $CO_2$ were made in the mountainous region of Srinagar-Garhwal, India (January to December 2006). Concentrations of $CO_2$ averaged $393\pm4.9$ ppm in 2006. Daily variations of $CO_2$ values showed minimum during the daytime (376.2 ppm) and peaked in the morning/evening (410.1 ppm). At monthly intervals, the $CO_2$ values varied from $367\pm11.14$ (May) to $425.2\pm13.54$ ppm (March). If divided on a seasonal basis, the values declined to minimum amounts in post-monsoon ($389.9\pm9.0$ ppm) and reached maximums during winter ($397.1\pm11.6$ ppm). Although phenology is significant in controlling $CO_2$ levels, short-term changes cannot be explained without the anthropogenic perturbations (e.g., vehicular pollution and forest fires). The $CO_2$ concentrations in Srinagar-Garhwal (393.4 ppm) were generally higher than those of other major monitoring locations around the world.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.280-286
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• 2005

Geological sequestration of carbon dioxide ($CO_2$) is one of the most effective strategies far long-term removal of greenhouse gas from atmosphere. This paper reviews three projects for the $CO_2$ sequestration in geological formation. A unique $CO_2$ injection into a marine aquifer has been successfully monitored with repeated surface seismic measurements in the North Sea Sleipner West field. The seismic images reveal the extent and internal shape of the $CO_2$ bubble. Massive miscible $CO_2$ has been injected into a complex fractured carbonate reservoir at the Weyburn oil filed. High-resolution time-lapse P-wave data were successfully obtained to map the features of $CO_2$ movements within the two thin zones of different lithology. From the time-lapse crosswell EM imaging at the Lost Hills oil field in central California, U.S.A., the replacement of brine with $CO_2$ has been confirmed through a decrease of conductivity. The conductivity image was successfully compared with induction logs observed in the two wells.