• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.507-516
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• 2018

The closed chamber method, which is one of the most commonly used method for measuring greenhouse gases produced in rice paddy fields, has limitations in measuring dynamic $CH_4$ flux with spatio-temporal constrains. In order to deal with the limitation of the closed chamber method, some studies based on open-path of eddy covariance method have been actively conducted recently. The aim of this study was to compare the $CH_4$ fluxes measured by open-path and closed chamber method in the paddy rice fields. The open-path, one of the gas ($CO_2$, $CH_4$ etc.) analysis methods, is technology where a laser beam is emitted from the source passes through the open cell, reflecting multiple times from the two mirrors, and then detecting. The $CH_4$ emission patterns by these two methods during rice cultivation season were similar, but the total $CH_4$ emission measured by open-path method were 31% less than of the amount measured by closed chamber. The reason for the difference in $CH_4$ emission was due to overestimation by closed chamber and underestimation by open-path. The closed chamber method can overestimate $CH_4$ emissions due to environmental changes caused by high temperature and light interruption by acrylic partition in chamber. On the other hand, the open-path method for eddy covariance can underestimate its emission because it assumes density fluctuations and horizontal homogeneous terrain negligible However, comparing $CH_4$ fluxes at the same sampling time (AM 10:30-11:00, 30-min fluxes) showed good agreements ($r^2=0.9064$). The open-path measurement technique is expected to be a good way to compensate for the disadvantage of the closed chamber method because it can monitor dynamic $CH_4$ fluctuation even if data loss is taken into account.

• Analytical Science and Technology
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• v.25 no.4
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• pp.230-235
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• 2012

It is to use many plastic materials as living essential goods. But when the fire is happened, owing to noxious gases, many men should be injured. Therefore as the noxious gases are measured by open path FT-IR spectrometer as remote monitoring, the demage of men could be minimized. Such this system consists of a Fourier transform spectrometer and infrared lamp fitted to long length. The study was to do the quantitative analysis on CO, $NO_2$, HCl, HF gas by remote monitoring open path FT-IR spectrometer. And the method of it should use MLR (multiple linearity regression) method. As result, It was confirmed to be more than 0.95 as $R^2$ of MLR. And then Urethane and PVC of plastic materials selected was burned, the concentration of polluted gases were measured by remote monitoring method.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.306-307
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• 2000

대기오염에 관한 연구가 진행되면서 광화학반응의 기여도가 높고, 인체에 직,간접으로 영향을 미치는 VOC를 포함한 비기준성 대기오염물질을 실시간으로 측정 할 수 있는 방법에 대한 필요성이 크게 증대하고 있다. Open-path 광학기기는 가스크로마토그래피 등 종래 sampling 방법과는 달리, 대상지역내 대기오염물질을 별도의 채취없이 실시간으로 측정함으로써, 대기오염물질 채취에서 야기되는 오차를 제거하고 여러화학종의 동적 변화에 관한 자료를 제공함으로써 대기오염물질 거동에 중요한 자료를 제공하고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.354-355
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• 2001

DOAS (Differential Optical Absorption Spectroscopy) System은 대기 중에 존재하는 기준물질들이 특정 파장영역에서 빛을 흡수하는 원리를 이용하고 있다. 현재 독일을 중심으로 한 유럽과 선진국에서는 대기 환경 기준물질의 모니터링 기술들이 주로 광 투과방식을 이용한 Open path의 모니터링 기술들을 개발하고 있다. 기존의 측정 방법과 Open Path 모니터링의 기법을 비교 할 때 Open path 시스템은 실시간 측정 및 분석이 가능하므로 기존의 화학적 측정방법에서 제기되어져왔던 화학 반응시의 방해 물질의 간섭제거 및 시간 분해도 향상등에 큰 장점이 있다. (중략)

• Analytical Science and Technology
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• v.26 no.2
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• pp.120-124
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• 2013

It was studied to analyze the $CO_2$, CO, $SO_2$ standard gases of combustion gases by the open path FT-IR spectrometer with passive mode for remote analysis of air pollutant and volcano gases without IR lamp. As result, it was confirmed to have good linearity with more than 0.9 as correlation coefficients on the calibration curve of $CO_2$, CO concentration by MLR method. But in the case of $SO_2$, because the correlation coefficients were 0.88, the linearity could be lower. Finally, the concentration of three gases was predicted on in-site fire experiment under the condition of quantitative analysis. It could measure high $CO_2$ concentration as predicted result, but didn't measure the CO and $SO_2$. According to the result, it was possible to measure the combustion gases to long distance by only open path FT-IR spectrometer without infrared lamp.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.103-111
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• 2023

Mountains area, especially walking in open space is important for special active field which is based on mountain terrain. Recent research on pedestrian-path includes elements about pedestrian and various environment by analyzing network, but it is mainly focusing on limited space except for data-poor terrain like a mountain terrain. This paper proposes an architecture to generate walking path considering the slope for mountain terrain open space through virtual network made of mesh. This architecture shows that it reflects real terrain more effective when measuring distance using slope and is possible to generate mountain walking path using open space unlike other existing services, and is verified through the test. The proposed architecture is expected to utilize for pedestrian-path generation way considering mountain terrain open space in case of distress, mountain rescue and tactical training and so on.

• Journal of Environmental Science International
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• v.29 no.4
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• pp.403-413
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• 2020

The purpose of this study is to understand the formation of internal wind paths of open space and its effect on meteorological factors and the generation of negative air ions. Various types of internal wind paths of open space were formed. Subsequently, changes in meteorological factors in each type were measured and the generated negative air ions were analyzed. The four key findings of the study are summarized as follows. First, the average wind speed formed inside the open space was analyzed such that the difference in wind speed was dependent on the difference in the composition of the wind path. Second, the negative air ion generation was observed to have the same trend as the average wind speed difference. Third, changes to the meteorological factors were more evident depending on the difference in wind path formation patterns. Solar radiation was expected to be highly affected by the physical structure (direction) of the target site. The relative humidity was found to show large difference depending on the different wind path type; however, this difference was significantly reduced when converting to absolute humidity. Fourth, it was found that the wind path formation type of open space affects meteorological factors through path analysis, and the changed meteorological factors affect the amount of generated negative air ions. Two conclusions can be obtained based on these results. First, the changes in internal wind speed formation of open space directly reduced the amount of generated negative air ions. Second, the changes in wind speed affect meteorological factors as well as the amount of generated negative air ions.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.173-183
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• 1996

In this paper, a new structure that can do fault detection and location of digial logic circuits more efficiently using current testing techniques is proposed. In the conventional method, observation point for steady state power supply current was only one, but in the proposed method more fault classes are divided for fault detection and location through the ovservation of steady state power supply current at two points. Also, it is shown that this structure can be easily applied in detection of stuck-open fault which is not easy to do testing with conventional current testing techniques. In the presented mehtod, an extra trasnistor is used, and current path is made compulsorily in the CMOS circuits in which no current path can be established in steady state, then it can be known that stuck-open tault is in the MOS transistor on the considering current path, if this path disappears due to stuck-open fault. The validity and the effectiveness is shwon, thorugh the SPICE simulation of circuits with fault and the current path search experiment using current path search program based on transistor short model wirtten in C language on SUN sparc workstation.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.1
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• pp.58-67
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• 1995

A path planning algorithm using a laser range finder are presented for real-tiem navigation of an autonomous guided vehicle. Considering that the laser range finder has the excellent resolution with respect to angular and distance measurements, a sophisticated local path planning algorithm is achieved by using the human's heuristic method. In the case of which the man knows not rhe path, but the goal direction, the man forwards to the goal direction, avoids obstacle if it appears, and selects the best pathway when there are multi-passable ways between objects. These heuristic principles are applied to the path decision of autonomous guided vehicle such as forward open, side open and no way. Also, the effectiveness of the established path planning algorithm is estimated by computer simulation in complex environment.

• Journal of Korea Multimedia Society
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• v.18 no.5
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• pp.682-690
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• 2015

Among location-based systems, a route search service is very highly utilized as a representative technique, but it provides relatively low accuracy when we find a route path on foot in our real environment. In this paper, we design and implement an optimized route search technique based on user experience utilizing open APIs as location-based services. Finally, we develop an Android-based application to provide this feature. In our experiment, we found that our technique enhanced performance by about 14-36% compared to previous solutions, such as route path searches using map APIs. In addition, the performance of our technique can be further enhanced, as the number of users who find such optimized route path is increasing.