• 대한기계학회논문집B
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• 제31권2호
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• pp.167-172
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• 2007

A new method that optimizes a control of hydrocarbon (HC) addition to diesel exhaust gas for HC type DeNOx catalyst system has been developed. These catalysts are called the HC-DeHOx catalyst in this paper. The system using HC-DeNOx catalyst requires a resonable quantity of hydrocarbons addition in the inlet gas of the catalyst, because the HC concentration in a diesel engine is so low that the HC is not sufficient for NOx conversion. It is expected that this study offers a robust data developing HC injection system.

• 한국환경생태학회지
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• 제24권5호
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• pp.539-546
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• 2010

본 숲에서 발생하는 음이온의 농도가 임상과 숲 관련인자에 따른 변이를 파악하고자, 강원도 고성군, 양양군에 위치한 국유림지역에서 52개의 방형구에서 산림조사와 음이온의 농도를 측정하고 관련성을 분석하였다. 측정된 음이온의 평균값 2,405개/$cm^3$는 일반적인 숲에서 보고된 2,000개/$cm^3$ 보다는 조금 높은 값이었다. 음이온 농도와 지형에서는 5% 유의수준에서, 음이온 농도와 토양수분, 해발고에서는 1% 유의수준에서 각각 정의 상관이 인정되었다. 조사지의 음이온 농도는 토양수분 수준간 고도의 통계적 유의성이 인정되었으며, 다습한 지역에서 평균 음이온 농도가 4,524.4개/$cm^3$로 가장 높았다. 지형에서는 계곡부 조사지의 평균 음이온 농도가 3,372.4개/$cm^3$로 가장 높았으며, 사면, 능선 순으로 점차 낮아지는 경향을 보였다. 측정시간대에서는 오전(12시 이전)에 측정된 평균 음이온 농도가 3,133.4개/$cm^3$로 가장 높았으며, 낮(12:00~15:00), 저녁(15시 이후) 순으로 점차 낮아지는 경향을 보였다. 임상에서는 활엽수 혼효림에서 측정된 평균 음이온 농도가 3,503.9개/$cm^3$로 가장 높았으며, 참나무림, 소나무림, 소나무-참나무 혼효림 순으로 점차 낮아지는 경향을 보였다. 이 연구의 결과는 치유의 숲 입지선정에 활용할 수 있을 것이라 사료된다.

• 한국산업보건학회지
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• 제17권3호
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• pp.235-244
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• 2007

By comparing the proteins from the workers exposed to styrene with the ones from controls, it may be possible to identify proteins that play a role in the occurrence and progress of occupational disease and thus to study the molecular mechanisms of occupational disease. In order to find the biomarkers for assessing the styrene effects early, before clinical symptoms develop and to understand the mechanisms of adverse health effects, we surveyed 134 employees, among whom 52 workers(30 male and 22 female) were chronically exposed to styrene in 10 glass-reinforced plastic boat manufacturing factories in Korea and 82 controls had never been occupationally exposed to hazardous chemicals including styrene. The age and drinking habits and serum biochemistry such as total protein, BUN and serum creatinine in both groups were significantly different. Exposed workers were divided into three groups according to exposure levels of styrene(G1, below 1/2 TLV; G2, 1/2 TLV to TLV; G3, above TLV). The mean concentration of airborne styrene in G1 group was $10.93{\pm}11.33ppm$, and those of urinary mandelic acid(MA) and phenylglyoxylic acid(PGA) were $0.17{\pm}0.21$ and $0.13{\pm}0.11g/g$ creatinine, respectively. The mean concentration of airborne styrene in G2 and G3 groups were $47.54{\pm}22.43$ and $65.33{\pm}33.47ppm$, respectively, and levels of urinary metabolites such as MA and PGA increased considerably as expected with the increase in exposure level of styrene. The airborne styrene concentration were significantly correlated to the urinary concentration of MA(r=0.784, p=0.000) and PGA(r=0.626, p<0.001). In the 2D electrophoresis, the concentration of five proteins including complement C3 precursor, alpha-1-antitrypsin(AAT), vitamin D binding protein precursor(DBP), alpha-1-B-glycoprotein(A1BG) and inter alpha trypsin inhibitor(ITI) heavy chain-related protein were significantly altered in workers exposed to styrene compared with controls. While expression of complement C3 precursor and AAT increased by exposure to styrene, expression of DBP, A1BG and ITI heavy chain-related protein decreased. These results suggest that the exposure of styrene might affects levels of plasma proteinase, carriers of endogenous substances and immune system. In particular, increasing of AAT with the increase in exposure level of styrene can explain the tissue damage and inflammation by the imbalance of proteinase/antiproteinase and decrease of DBP, A1BG and ITI heavy chain-related protein in workers exposed to styrene is associated with dysfunction and/or declination in immune system and signal transduction

• 한국환경과학회지
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• 제28권7호
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• pp.595-606
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• 2019

This research investigated the characteristics of CO, $CO_2$, and $NO_2$ concentrations at main subway stations in Busan. The annual mean CO concentrations at the Suyeong and Nampo stations were 0.75 ppm and 0.48 ppm, respectively. Annual $CO_2$ concentration at the Seomyeon 1- platform was 649 ppm. The $NO_2$ concentrations at the Seomyeon 2- waiting room and the Yeonsan station were 0.048 ppm and 0.037 ppm, respectively. CO concentration was highest at two times of the day, and was proportional to the number of passengers commuting to and from work. The CO and $CO_2$ concentrations were highest in winter, but $NO_2$ concentration was highest in spring. CO and $CO_2$ concentrations were highest on Saturday and lowest on Sunday. The correlation of CO and $NO_2$ concentrations measured at the subway stations with those at the ambient air quality station were highest at the Seomyeon 1 and 2- waiting room and Jeonpodong. The correlation was lowest at the Yeonsan and Yeonsandong station. The number of days when $CO_2$ concentration exceeded 700 ppm over the last three years at the Seomyeon 1- platform was 174. The findings of this research are expected to deepen understanding of the fine particle characteristics at subway stations in Busan and be useful for developing a strategy for controlling urban indoor air quality.

• 한국인터넷방송통신학회논문지
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• 제24권2호
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• pp.119-125
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• 2024

본 논문에서는 인공지능 주의환기 보상전략 시스템이 발달장애인의 데이터 라벨링 작업 주의집중력에 미치는 효과를 분석하였다. 주의집중력의 척도로는 세션별 작업 정확도와 작업수행량을 사용하였다. 연구 결과, 중재가 적용된 후 연구대상자 모두 자율작업 대비 주의집중력에서 유의미한 향상이 관찰되었다. 이러한 결과는 인공지능 기술이 발달장애인의 데이터 라벨링 작업 중 주의집중력 향상에 긍정적으로 작용할 수 있음을 의미한다. 본 연구는 인공지능 기술의 적용이 발달장애인의 데이터 라벨링 작업 정확도를 향상하여 학습데이터의 품질을 높일 수 있음을 보여주고 있으며, 발달장애인의 데이터라벨링 관련 직업훈련 프로그램에 중요한 시사점을 제공하리라 본다.

• 대기
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• 제29권5호
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• pp.585-597
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• 2019

This study evaluates the performance of Weather Research and Forecasting (WRF) model in simulating temperature over the COordinated Regional climate Downscaling EXperiment-East Asia (CORDEX-EA) Phase 2 domain for the reference period (1981~2005), and assesses the changes in temperature and its extremes in the mid-21st century (2026~2050) under global warming based on Representative Concentration Pathway (RCP) scenarios. MPI-ESM-LR forced by two RCP scenarios (RCP2.6 and RCP8.5) is used as initial and lateral boundary conditions. Overall, WRF can capture the observed features of temperature distribution reflecting local topographic characteristic, despite some disagreement between the observed and simulated patterns. Basically, WRF shows a systematic cold bias in daily mean, minimum and maximum temperature over the entire domain. According to the future projections, summer and winter mean temperatures over East Asia will significantly increase in the mid-21st century. The mean temperature rise is expected to be greater in winter than in summer. In accordance with these results, summer (winter) is projected to begin earlier (later) in the future compared to the historical period. Furthermore, a rise in extreme temperatures shows a tendency to be greater in the future. The averages of daily minimum and maximum temperatures above 90 percentiles are likely to be intensified in the high-latitude, while hot days and hot nights tend to be more frequent in the low-latitude in the mid-21st century. Especially, East Asia would be suffered from strong increases in nocturnal temperature under future global warming.

• 대기
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• 제25권1호
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• pp.85-97
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• 2015

This study is to investigate future changes in carbon cycle using the HadGEM2-Carbon Cycle simulations driven by $CO_2$ emissions. For experiment, global carbon budget is integrated from the two (8.5/2.6) representative concentration pathways (RCPs) for the period of 1860~2100 by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (Had-GEM2-CC). From 1985 to 2005, total cumulative $CO_2$ amount of anthropogenic emission prescribed as 156 GtC. The amount matches to the observed estimates (CDIAC) over the same period (136 GtC). As $CO_2$ emissions into the atmosphere increase, the similar increasing tendency is found in the simulated atmospheric $CO_2$ concentration and temperature. Atmospheric $CO_2$ concentration in the simulation is projected to be 430 ppm for RCP 2.6 at the end of the twenty-first century and as high as 931 ppm for RCP 8.5. Simulated global mean temperature is expected to rise by $1.6^{\circ}C$ and $3.5^{\circ}C$ for RCP 2.6 and 8.5, respectively. Land and ocean carbon uptakes also increase in proportion to the $CO_2$ emissions of RCPs. The fractions of the amount of $CO_2$ stored in atmosphere, land, and ocean are different in RCP 8.5 and 2.6. Further study is needed for reducing the simulation uncertainty based on multiple model simulations.

• The Korean Journal of Ecology
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• 제28권3호
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• pp.169-180
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• 2005

이 종설은 산성강하물의 원인물질을 개관하고 한국, 아시아 및 세계의 산성 강하물량을 추산하며 산성비 실태를 밝히는 데 목적이 있다. 서울의 이산화황$(SO_2)$ 농도는 $1996\sim2003$년 사이에 연평균 10%씩 감소하였고 이산화질소$(NO_2)$ 농도는 8%씩 증가하였다. 서울의 빗물은 $1980\sim1991$년 사이에 연평균 pH $4.19\sim4.68$의 심한 산성비가 내렸다. 빗물의 산성도를 총 음이온 농도로 평가한 결과 한국 평균(101.3 ${\mu}equiv{\cdot}L^{-1}$), 광릉(199.2 ${\mu}equiv{\cdot}L^{-1}$) 및 관악산(341.5 ${\mu}equiv{\cdot}L^{-1}$)의 순으로 높았다. 세계 16개 국 38장소의 빗물의 총 음이온 농도를 기준으로 빗물의 산성도를 5등급으로 구분한 결과 말레이시아의 Tana Rata(16.2 ${\mu}equiv{\cdot}L^{-1}$)가 가장 청정한 비가, 중국의 중경(541.1 ${\mu}equiv{\cdot}L^{-1}$)이 가장 오염된 비가 내리고 있음이 비교되었다. 앞으로 산성 강하물은 구미에서 감소되지만 아시아 중남미 아프리카에서 증가될 전망이다.

• 한국물환경학회지
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• 제22권5호
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• 한국농공학회논문집
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• 제63권3호
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• pp.87-95
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• 2021

The Doam Lake Watershed is one of Gangwon-do's non-point source management areas. This area has a lot of snowfall in winter, and it is expected that there will be a lot of soil erosion in early spring due to snow melting. In this study, snow melting was monitored in the Doam Lake watershed from February to 3, 2020. It was conducted to analyze the water quality changes by calculating the concentration of non-point source pollution caused by snowmelt, and to compare the concentration of water quality during snowmelt event with rainfall and non-rainfall event. As a result of water quality analysis, Event Mean Concentration (EMC) at the first monitoring was SS 33.9 mg/L, TP 0.13 mg/L, TN 4.33 mg/L, BOD 1.35 mg/L, TOC 1.84 mg/L. At the second monitoring, EMC were SS 81.3 mg/L, TP 0.15 mg/L, TN 3.12 mg/L, BOD 1.32 mg/L, TOC 3.46 mg/L. In parameter except SS, it showed good water quality. It is necessary to establish management measures through continuous monitoring.