• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.259-264
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• 1999

The $CO_2$ measuring system using infrared sensor has the variance according to the temperature change. Therefore, the temperature compensation should be needed to obtain a reliable measurement. In this study, the sensor module consist of infrared $CO_2$ Sensor, IR Source, pipe and the heater and measuring system has amplifier, A/D converter and microprocessor. And we suggest a method to reduce the error by using the PID temperature control. We use optimum parameters setting of Ziegler & Nichols as well as PID temperature control algorithm for the temperature compensation. In this method, PID optimum parameter is set from dummy time(L) and maximum slope(R). As a result of using this PID temperature control, it is founded that it has the fast response and low steady state error. Therefore, it is certainly proved that this is very suitable algorithm to correct the error on measurement.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.265-267
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• 2007

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.9-9
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• 2007

• Journal of The Korean Astronomical Society
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• v.54 no.2
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• pp.49-60
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• 2021

Observations of line of sight (LOS) Doppler velocity and non-thermal line width in the off-limb solar corona are often used for investigating the Alfvén wave signatures in the corona. In this study, we compare LOS Doppler velocities and non-thermal line widths obtained simultaneously from two different instruments, Coronal Multichannel Polarimeter (CoMP) and Hinode/EUV Imaging Spectrometer (EIS), on various off-limb coronal regions: flaring and quiescent active regions, equatorial quiet region, and polar prominence and plume regions observed in 2012-2014. CoMP provides the polarization at the Fe xiii 10747 Å coronal forbidden lines which allows their spectral line intensity, LOS Doppler velocity, and line width to be measured with a low spectral resolution of 1.2 Å in 2-D off limb corona between 1.05 and 1.40 RSun, while Hinode/EIS gives us the EUV spectral information with a high spectral resolution (0.025 Å) in a limited field of view raster scan. In order to compare them, we make pseudo raster scan CoMP maps using information of each EIS scan slit time and position. We compare the CoMP and EIS spectroscopic maps by visual inspection, and examine their pixel to pixel correlations and percentages of pixel numbers satisfying the condition that the differences between CoMP and EIS spectroscopic quantities are within the EIS measurement accuracy: ±3 km s-1 for LOS Doppler velocity and ±9 km s-1 for non-thermal width. The main results are summarized as follows. By comparing CoMP and EIS Doppler velocity distributions, we find that they are consistent with each other overall in the active regions and equatorial quiet region (0.25 ≤ CC ≤ 0.7), while they are partially similar to each other in the overlying loops of prominences and near the bottom of the polar plume (0.02 ≤ CC ≤ 0.18). CoMP Doppler velocities are consistent with the EIS ones within the EIS measurement accuracy in most regions (≥ 87% of pixels) except for the polar region (45% of pixels). We find that CoMP and EIS non-thermal width distributions are similar overall in the active regions (0.06 ≤ CC ≤ 0.61), while they seem to be different in the others (-0.1 ≤ CC ≤ 0.00). CoMP non-thermal widths are similar to EIS ones within the EIS measurement accuracy in a quiescent active region (79% of pixels), while they do not match in the other regions (≤ 61% of pixels); the CoMP observations tend to underestimate the widths by about 20% to 40% compared to the EIS ones. Our results demonstrate that CoMP observations can provide reliable 2-D LOS Doppler velocity distributions on active regions and might provide their non-thermal width distributions.

• Atmosphere
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• v.29 no.5
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• pp.511-523
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• 2019

A new Korean Meteorological Administration (KMA) airborne measurement platform has been established for regular observations for scientific purpose over South Korea since late 2017. CRDS G-2401m analyzer mounted on the King Air 350HW was used to continuous measurement of CO₂, CH₄ and CO mole fraction. The total uncertainty of measurements was estimated to be 0.07 ppm for CO₂, 0.5 ppb for CH₄, and 4.2 ppb for CO by combination of instrument precision, repeatability test simulated in-flight condition and water vapor correction uncertainty. The airborne vertical profile measurements were performed at a regional Global Atmosphere Watch (GAW) Anmyeon-do (AMY) station that belongs to the Total Carbon Column Observing Network (TCCON) and provides concurrent observations to the Greenhouse Gases Observing Satellite (GOSAT) overpasses. The vertical profile of CO₂ shows clear altitude gradient, while the CH₄ shows non-homogenous pattern in the free troposphere over Anmyeon-do. Vertically averaged CO₂ at the altitude between 1.5 and 8.0km are lower than AMY surface background value about 7 ppm but higher than that observed in free troposphere of western pacific region about 4 ppm, respectively. CH₄ shows lower level than those from ground GAW stations, comparable with flask airborne data that was taken in the western pacific region. Furthermore, this study shows that the combination of CH₄ distribution in free troposphere and trajectory analysis, taking account of convective mixing, is a useful tool in investigating CH₄ transport processes from tropical region to Korean region in winter season.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.51-60
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• 2003

Rice, which occupies about 60% of the farmland in Korea, is a staple crop in Asia. It not only absorbs $CO_2$ from the atmosphere, but also emits carbon in a form of CH$_4$. It has a potential role in the global budget of greenhouse gases because of its relative contributions of carbon absorption and emission associated with changing hydrologic cycle. To better understand its current and future role, seasonal variations of energy and $CO_2$ exchange in this critical ecosystem need to be quantified. The purpose of this study was to measure, document and understand the exchange of energy and $CO_2$ in a typical rice paddy in Korea throughout the whole growing season. Since late April of 2002, we have conducted measurements of energy and $CO_2$ exchange in a rural rice paddy at Hari site, one of the Korea regional network of tower flux measurement (KoFlux). After the quality control and gap-filling, the observed fluxes were analyzed in the context of micrometeorology and biophysics. $CO_2$ and energy exchanges varied significantly with land cover changes (e.g., plant growth stages), in addition to changes in weather and climate conditions. This study, reporting first direct measurement of energy and $CO_2$ exchange over a rice paddy in Korea, would serve as a useful database as one of the reference sites in AsiaFlux and FLUXNET.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.315-323
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• 2018

Fossil fuel combustion during fishing activities is a major contributor to climate changes in the fishing industry. The Tier1 methodology calculation and on-site continuous measurements of the greenhouse gas were carried out through the use of fuel by the coastal and offshore gillnet (blue crabs and yellow croaker) and trap (small octopus and red snow crab) fishing boats in Korea. The emission comparison results showed that the field measurements are similar to or slightly higher than the Tier1 estimates for coastal gillnet and trap. In offshore gillnet and trap fisheries, Tier1 estimate of greenhouse gases was about $1,644-13,875kg\;CO_2/L$, which was more than the field measurement value. The $CO_2$ emissions factor based on the fuel usage was $2.49-3.2kg\;CO_2/L$ for coastal fisheries and $1.46-2.24kg\;CO_2/L$ for offshore fisheries. Furthermore, GHG emissions per unit catch and the ratio of field measurement and Tier1 emission estimate were investigated. Since the total catch of coastal fish was relatively small, the emission per unit catch in coastal fisheries was four to eight times larger. The results of this study could be used to determine the baseline data for responding to changes in fisheries environment and reducing greenhouse gas emission.

• Journal of Chest Surgery
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• v.14 no.3
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• pp.228-234
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• 1981

Measurement of cardiac output by thermodilution method is easy to perform and can be repeated at very short intervals and offers a number of theoretical and practical advantages. The purpose of this paper is to reevaluate the accuracy and reproducibility of the thermodilution cardiac output by comparing the results with those obtained by the direct Fick technique. From January through April 1981 [4 months], 26 simultaneous cardiac output measurements were made using thermodilution and direct Fick methods in 12 patients in the intensive care unit of Severance Hospital following open heart surgery. The average age of the patients was $34.8{\pm}12.0$ [SD] years [range; 17-57 years]. For cardiac output determination by thermodilution technique [$CO_TD$], a Swan-Ganz Thermodilution Catheter, Model 93A-131-7F [Edwards Laboratories], a Cardiac Output Computer, Model 9520A, and Strip Chart Recorder, Model 9810 [Edwards Laboratories] were used. For the determination of cardiac output by direct Fick principle [$CO_Fick$], a Van Slyke Manometric Apparatus [Thomas] for the measurements of arteriovenous oxygen content difference and a Collin`s Respirometer with Kymograph for the measurement of oxygen consumption were used. The correlation between the simultaneously measured $CO_TD$ and $CO_Fick$ was found to be $CO_Fick$ = 0.95.$CO_TD$ + 0.1073, [r= 0.9777, P < 0.001 ]. For 26 double or triple determinations of $CO_TD$, the values ranged from 1.77 L/min to 6.66 L/min, with a reproducibility of 2.18%. The maximum difference of $CO_TD$ for $CO_Fick$ was between +11.99% and -12,99% [$Mean{\pm}SD$ = $6.07{\pm}3.97$%]. Measurement of cardiac output by thermodilution method provides a simple, rapid, reproducible and highly accurate method for multiple cardiac output measurements suitable for use at the bedside. Comparison of Cardiac Output Determination by Direct Fick and Thermodilution Method in Man.

• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.329-334
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• 2004

Functional residual capacity (FRC) is an important diagnostic parameter measured using $N_{2}$ analyzer. Since $N_{2}$ analyzer is expensive as well as cumbersome for use of noisy vacuum pump, the FRC measurement becomes possible only in large well-equipped hospitals. The present study introduced a new $TN_{2}$ wash-out technique to measure FRC by $O_{2}/CO_{2}$ analysis, which is relatively cheaper and much simpler to apply. Slower $O_{2}$ response was compensated for high frequency to be coincided with $CO_{2}$ response, thereby enabled indirect, but accurate $N_{2}$ concentration measurement. FRC was estimated by continuous integration of expired $N_{2}$ volume obtained with air flow signal. Experiment with 3 L syringe, a standard calibration device recommended by the American Thoracic Society, demonstrated less than 1% error at 0, 1, and 2 L. Correlation coefficient was almost ideal, guaranteeing linear estimation of FRC. The present technique is inexpensive and simple to apply, thus should he of great convenience.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.102-107
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• 2007

A fast response $CO_2$ ($fCO_2$) analyzer for real-time measurement of carbon dioxide concentration during transient states of internal combustion engines has been developed. This analyzer uses non-dispersive infrared absorption (NDIR) technique for measuring $CO_2$ concentration and Kalman filter for removing noise components from output signals. The analyzer has good linearity, repeatability and drift with a response time of 11 ms; it is sufficiently fast to detect $CO_2$ concentration during transient states of internal combustion engines. The $fCO_2$ analyzer was used to measure transient $CO_2$ concentration of exhaust gas of the SI engine with a standard gas analyzer, and the signal of the $fCO_2$ analyzer was compared to that of the standard gas analyzer. The two concentrations were well matched during the steady state, and the $fCO_2$ analyzer could measure the variations of $CO_2$ concentration during the transient state.