• 한국대기환경학회지
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• 제24권5호
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• pp.574-583
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• 2008

The results of HAPs emission data using TRI (Toxic Release Inventory), SODAM (Source Data Management system) were investigated and the emissions of 7 heavy metals from their sources and emission processes were also analyzed. Questionnaire for source data analysis as well as the stack sampling were carried out for 17 factories among 6 selected industrial types. The annual amount of emissions was estimated based on the measured concentration and flow rates. All sources were operated with high efficiency control devices and the concentration levels of all heavy metals were shown to be below 0.1 to of regulation standard. The highest emission source of heavy metals was steel manufacturing industry with the annual emission of 342.9 kg/yr and followed by hazardous waste incinerator, paint manufacturing, nonferrous metal manufacturing, rolling & press goods manufacturing and storage battery manufacturing. In the case of Hg, the emissions were quite significant from electric acros of steel manufacturing industry, although the concentration level was below the emission standard, showing the necessity of specific care for its management.

• Journal of Preventive Medicine and Public Health
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• 제47권5호
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• pp.253-257
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• 2014

Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.63-66
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• 2003

This study applied a hydrogeological field survey and isotope investigation to identify source locations and delineate pathways of groundwater contamination by nitrogen compounds. The infiltration and recharge processes were analyzed with groundwater-level fluctuation data and oxygen-hydrogen stable isotope data. The groundwater flow pattern was investigated through groundwater flow modeling and spatial and temporal variation of oxygen isotope data. Based on the flow analysis and nitrogen isotope data, source types of nitrate contamination in groundwater are identified. Groundwater recharge largely occurs in spring and summer due to precipitation or irrigation water in rice fields. Based on oxygen isotope data and cross-correlation between precipitation and groundwater level changes, groundwater recharge was found to be mainly caused by irrigation in spring and by precipitation at other times. The groundwater flow velocity calculated by a time series of spatial correlations, 231 m/yr, is in good accordance with the linear velocity estimated from hydrogeologic data. Nitrate contamination sources are natural and fertilized soils as non-point sources, and septic and animal wastes as point sources. Seasonal loading and spatial distribution of nitrate sources are estimated by using oxygen and nitrogen isotopic data.

• 로봇학회논문지
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• 제12권4호
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• pp.402-410
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• 2017

Acoustic based localization is essential to operate autonomous robotic systems in underwater environment where the use of sensorial data is limited. This paper proposes a localization method using artificial underwater acoustic sources. The proposed method acquires directional angles of acoustic sources using time difference of arrivals of two hydrophones. For this purpose, a probabilistic approach is used for accurate estimation of the time delay. Then, Gaussian sum filter based SLAM technique is used to localize both acoustic sources and underwater vehicle. It is performed by using bearing of acoustic sources as measurement and inertial sensors as prediction model. The proposed method can handle directional ambiguity of time difference based source localization by generating Gaussian models corresponding to possible locations of both front and back sides. Through these processes, the proposed method can provide reliable localization method for underwater vehicles without any prior information of source locations. The performance of the proposed method is verified by experimental results conducted in a real sea environment.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E1호
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• pp.9-18
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• 2006

Aerosol hygroscopic properties were measured by a tandem differential mobility analyzer (TDMA) system during the Aerosol Characterization Experiment (ACE)-Asia campaign from 31 March to 1 May 2001. Two high flow differential mobility analyzers (DMAs) were used to maximize the count rate on board the Center for Interdisciplinary Remotely Piloted Aircraft (CIRPAS) Twin Otter aircraft. Hygroscopic growth factor distributions of particles having initial dry nanoparticle diameters of 0.040, 0.059, 0.086, 0.126, 0.186, 0.273, 0.400, and $0.586{\mu}m$ were measured during 19 research flights. Data collected during 12 of those flights were used to investigate aerosol mixing state and the influence of aerosol source region on size-resolved hygroscopicity. The uniformity in size-resolved hygroscopicity was quantified to facilitate comparison between measurements made in different air masses. Hygroscopic growth factors are strongly dependent on source region and sizes. Mean hygroscopic growth factors were observed to be greatest when the air mass origin was from the south. The mean growth factors for continental sources decreased with initial size from 1.47 to 1.27 for $0.040{\mu}m\;and\;0.586{\mu}m$, but increased with initial size from 1.44 to 1.8 for $0.040{\mu}m\;and\;0.400{\mu}m$ dry diameters for marine sources.

• 한국대기환경학회지
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• 제14권3호
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• pp.191-208
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• 1998

Estimations of dry and wet depositions in Korea and the size distributions of yellow sand above Korea have been carried out using the Eulerian aerosol model with the simulated meteorological data from the SNU mesoscale meteorological model. The estimated particle size distribution in Korea shows a bimodal distribution with peak values at 0.6 pm and 7 pm and a minimum at 2 pm in the lower layer However, as higher up, the bimodal distribution becomes an unimodal distribution with a peak value at 4∼5mm. Among the total amount of yellow sand deflated in the source regions , the dry and wet deposition fluxes were about 92%, and about 1.3∼0.5%, repectively, and the rest(5∼6%) is suspended in the air, Most of dust lifted in the air during the clear weather is deposited in the vicinity of the source regions by dry deposition and the rest undergoes the long -range transport with a gradual removal by the wet deposition processes. Over Korean peninsula, the total amount of yellow sand suspended in the air was about 6∼8% of the emissions in the source region and the dry and wet deposition fluxes were about 0.005∼0.7% and 0.003∼0.051% of the total emitted amount, repectively. It is estimated that 2.7∼8.9 mesa-tons of yellow sand is transported annually over the Korean peninsula with the annual mean dry deposition of 2.1∼490 kilo-tons and the annual mean wet deposition of 1.5∼65 kilo-tons.

• 한국물환경학회지
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• 제30권2호
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• pp.159-165
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• 2014

Vegetative Filter Strip (VFS) is one of effective Best Management Practices (BMPs) to prevent sediment-laden water problem, is installed at the edge of source area such agricultural area so that sediment occurred in source area is trapped by VFS before it flow into stream or river. Appropriate scale of it needs to be simulated before it is installed, considering various field conditions. In this study, a model using VFSMOD-w model and Genetic Algorithm to determine effective VFS length was developed, it is available to calibrate input parameter related to source area sediment yield through thousands of VFSMOD-w simulations. Useful DBs, moreover, are stored in the model so that very specific input parameters can be used with reasonable values. Compared simulated values to observed data values for calibration, R2 and Nash-Stucliffe model efficiency coefficient were 0.74 and 0.65 in flow comparison, and 0.89 and 0.79 in sediment comparison. The model determined 1.0 m of Filter Length, 0.18 of Filter Slope, and 0.2 cm of Filter Media Spacing to reduce 80% of sediment by VFS. The model has not only Auto-Calibration module also DBs for specific input parameters, thus, the model is expected to be used for effective VFS scale.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.779-780
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• 2015

IoT가 시대의 핵심기술로 회자되면서 다양한 IoT제품들이 개발 되고 있다. 오픈소스 하드웨어인 Arduino와 IoT플랫폼인 Temboo를 이용하여 차량의 CAN정보를 분석 후 휴대폰으로 확인 및 분석, 활용할 수 있는 차량용 IoT 응용시스템을 구현해봄으로서 저비용으로 IoT 응용시스템을 구현하여 사용할 수 있는 방법을 연구하였다. 그리고 이에 따른 문제점과 개선방안 등을 제시한다.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.243-251
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• 2021

Real-Time Kinematic (RTK) is a phase-based differential GNSS technique and uses additional observations from permanent reference stations to mitigate or eliminate effects like atmospheric delays or satellite clocks and orbit errors. In particular, as the position accuracy required in the fields of autonomous vehicles and drones is gradually increasing, the demand for RTK-based precise navigation that can provide cm-level position is increasing. Recently, with the rapid growth of the open-source software market, the use of open-source software for building navigation system of unmanned vehicles, which is difficult to mount an expensive GNSS receivers, is gradually increasing. RTKLIB is an open-source software package that can perform RTK positioning and is widely used for research and education purposes. However, since the performance and stability of RTK algorithm of RTKLIB is inevitably inferior to that of commercial GNSS receivers, users need to verify whether RTKLIB can satisfy the navigation performance requirements of unmanned vehicles. Therefore, in this paper, the performance evaluation of the RTK positioning algorithm of RTKLIB was performed using GNSS observation data acquired in a dynamic environment. Therefore, in this paper, the RTK positioning performance of RTKLIB was evaluated using GNSS observation data acquired in a dynamic environment. Our results show that the current RTK algorithm of RTKLIB is not suitable for precise navigation of unmanned vehicles.

• 감성과학
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• 제17권2호
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• pp.55-62
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• 2014

본 연구에서는 PMV 온열환경이 변화함에 따라 LED광원의 조도가 시작업 성능에 미치는 영향을 분석하기 위해 오류검색수정작업 평가지를 개발하였고, 오류검색수정작업의 정확도 및 소요시간을 분석하였다. 또한 작업을 진행하면서 느끼는 시각피로도에 대한 설문을 실시하여 주관적인 평가도 병행하였다. 본 실험의 PMV 온열환경은 온도 $17{\pm}1{\sim}29{\pm}1^{\circ}C$, 습도 $50{\pm}5{\sim}60{\pm}5%$의 범위에서 PMV 값에 따라 4가지 형태를 구성하였으며, LED광원의 조도는 400lx, 700lx, 1000lx의 3가지 형태로 구성하여 실험을 진행하였다. 오류검색수정작업의 정확도(LED p 값=0.058, PMV*LED p값=0.083) 및 소요시간(LED p값=0.004, PMV p값=0.000)은 PMV 온열환경과 LED광원의 조도 변화에 모두 유의하였으나, 피로도는 PMV 온열환경(p값=0.003)과 유의한 차이를 보였다.