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제주도 지하수 질산염 농도의 시·공간적 변화 특성: 장기(1993-2015) 모니터링 자료의 평가
김호림(Ho-Rim Kim),오준섭(Junseop Oh),도현권(Hyun-Kwon Do),이경진(Kyung-Jin Lee),현익현(Ik-Hyun Hyun),오상실(Sang-Sil Oh),감상규(Sang-Kyu Kam),윤성택(Seong-Taek Yun) 대한자원환경지질학회 2018 자원환경지질 Vol.51 No.1
1993년부터 2015년까지 관측된 제주도 지하수 장기모니터링 관측정(N = 4,835)에서 수집된 지하수 수질자료(N = 21,568)를 기반으로 질산성질소의 시공간적 변동 특성을 평가하였다. 제주도 지하수의 질산성질소 농도의 중앙값은 2.5 mg/L로서 다른 국가나 대륙의 조사 결과에 비해 다소 높거나 유사한 것으로 나타났다. 또한 지하수 용도, 행정구역 및 고도 별로 유의한 차이를 보였다. 특히, 산간 지역에 비해 저지대 해안가에 위치한 농업 및 주거지역에서 농도가 높음을 확인하였다. Mann-Kendall 및 Sen’s slope 분석을 활용한 질산성질소 농도의 추세 분석 결과, 하류 저지 대에 비해 중산간지역에서의 질산성질소 농도 증가 경향이 뚜렷하였다. 제주도 내 토지 피복의 시계열 변화 특성과 결부 지어 보면, 중산간지역의 오염 증가 추세는 농업지역의 확장 등 인위적 활동 증가에 기인한 결과로 판단된다. 반면,기지정된 지하수자원특별관리구역에서는 전반적으로 질산성질소 농도의 감소 경향이 나타났는데, 이는 지하수 관리 측면에서 수질관리를 위한 적극적인 정책이 유효함을 시사한다. 본 연구에서는 제주도 지하수의 질산성질소 오염관리를 위한 적정 방안을 제안한다. The spatio-temporal variations of nitrate concentrations in groundwater of Jeju Island were evaluated by an analysis of time series groundwater quality data (N = 21,568) that were collected from regional groundwater monitoring (number of wells = 4,835) for up to 20 years between 1993 and 2015. The median concentration of NO 3 -N is 2.5 mg/L, which is slightly higher than those reported from regional surveys in other countries. Nitrate concentrations of groundwater in wells tend to significantly vary according to different water usage (of the well), administrative districts, and topographic elevations: nitrate level is higher in low-lying agricultural and residential areas than those in high mountainous areas. The Mann-Kendall trend test and Sen’s slope analysis show that nitrate concentration in mid-mountainous areas tends to increase, possibly due to the expansion of agricultural areas toward highland. On the other hand, nitrate concentrations in the Specially Designated Groundwater Quality Protection Zones show the temporally decreasing trend, which implies the efficiency of groundwater management actions in Jeju. Proper measures for sustainable groundwater quality management are suggested in this study.
RF Watermark Backward Compatibility Tests for the ATSC Terrestrial DTV Receivers
Sung Ik Park,Jeongchang Kim,Daewon Choi,Heung Mook Kim,Wangrok Oh IEEE 2011 IEEE transactions on broadcasting Vol.57 No.2
<P>In a single frequency network (SFN) for the Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, co-channel interference induced by the multiple transmitters and/or repeaters which use the same output channel is inevitable. Since the presence of interference results in the performance degradation of the SFN, it is crucial to manipulate the interference by adjusting the transmit power and the emission time of each transmitter and repeater within the SFN. In the ATSC terrestrial DTV system, in order to facilitate the interference manipulation process, a transmitter identification (TxID) signal which is embedded in the transmit signal from each transmitter and repeater is recommended. However, such an embedded signal may degrade the DTV signal quality even though the injection level of the TxID signal is very low compared to the DTV signal. Hence, the effect of the TxID signal on the DTV signal needs to be investigated before deploying the SFN with TxID signal. In this paper, the effect of the TxID signal on the performance of legacy DTV receivers is investigated not only with extensive computer simulation but also with laboratory and field tests. According to the various test results, the average performance loss of the conventional DTV receiver due to the TxID signal is less than 0.2 dB when the TxID signal is injected at 30 dB below the DTV signal power.</P>
Oh, Jeong-Ik,Lee, Jechan,Lee, Taewoo,Ok, Yong Sik,Lee, Sang-Ryong,Kwon, Eilhann E. Elsevier Science B.V. Amsterdam 2017 Journal of CO₂ utilization Vol.20 No.-
<P><B>Abstract</B></P> <P>This study laid great emphasis on strategic use of CO<SUB>2</SUB> as reaction medium and raw material for energy recovery from food waste via shifting carbon distribution from pyrolytic oil to syngas. Thus, the mechanistic understanding of CO<SUB>2</SUB> in pyrolysis of food waste was investigated systematically in this study. To this end, the thermo-gravimetric analysis (TGA) of food waste in N<SUB>2</SUB> and CO<SUB>2</SUB> was carried out. The TGA test evidenced that any physical aspects describing the thermal degradation such as onset and end temperature were not influenced by CO<SUB>2</SUB>. A scale-up experimental work was also conducted with a batch-type tubular reactor to figure out any chemical influences induced by CO<SUB>2</SUB> in pyrolysis of food waste. CO<SUB>2</SUB> in pyrolysis of food waste imparted the genuine capability for shifting carbon distribution from pyrolytic oil to syngas. CO<SUB>2</SUB> led to carbon distribution shift from pyrolytic oil to syngas (<I>i.e.</I>, enhanced generation of H<SUB>2</SUB> and CO). Particularly, the generation of CO evolved from pyrolysis of food waste in CO<SUB>2</SUB> was substantially enhanced by a factor of 100 at 800°C. Thus, all experimental findings in this study significantly introduced an innovative way to use CO<SUB>2</SUB> as energy resources, thereby substantially boosting the sustainability in the thermo-chemical process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Utilizing CO<SUB>2</SUB> as reaction medium in thermo-chemical process. </LI> <LI> Shifting carbon distribution from pyrolytic oil to syngas. </LI> <LI> Enhanced generation of CO from food waste using CO<SUB>2</SUB> by a factor of 100. </LI> </UL> </P>
Augmented Data Transmission for the ATSC Terrestrial DTV System
Sung Ik Park,Hyoungsoo Lim,Heung Mook Kim,Yiyan Wu,Wangrok Oh IEEE 2012 IEEE transactions on broadcasting Vol.58 No.2
<P>In this paper, we propose a novel Augmented Data Transmission (ADT) system which can transmit an additional data stream in the Advanced Television Systems Committee (ATSC) terrestrial DTV system. The proposed ADT system can offer an additional data of rate up to a few megabits per second (Mbps) based on hierarchical modulation, DTV signal cancellation, and advanced error correction code. The proposed ADT system significantly enhances capability compared with the data transmission schemes used in the transmitter identification (TxID) system. Since the proposed ADT system uses the in-band hierarchical modulation, it does not require any additional RF spectrum to increase the data capacity in a 6 MHz RF channel. Meanwhile, the ADT system has negligible impact to legacy receivers, if the proposed ADT system is deployed over the frequency bands occupied by ATSC A/53 or A/153 services.</P>
Additional Data Transmission Based on Sequence Phase Modulation for the ATSC Terrestrial DTV System
Sung Ik Park,Jeongchang Kim,Donghoon Kang,Heung Mook Kim,Wangrok Oh IEEE 2013 IEEE transactions on broadcasting Vol.59 No.4
<P>Several previous studies have demonstrated that additional low-rate data can be transmitted in Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) systems by modulating the polarity of the transmitter identification (TxID) signal. Previously proposed additional-data transmission schemes can offer an additional reliable transmission channel, and thus they have a very large coverage area compared to that of a DTV signal. Unfortunately, as the cost of a reliable transmission, they have a limitation in their maximum data rate. In this paper, we propose a new additional data transmission scheme based on sequence phase modulation (SPM) to increase the data rate. The proposed scheme exploits not only the polarity but also the phase of a TxID signal, and thus it significantly enhances the data rate compared to conventional schemes.</P>
Evaluation of Changes in Agricultural Stream Water Quality of Small Watershed in Jeonnam Province
Sung-Woo Kim,Sun Kook Kim,Hyeon Ji Kim,So Yeon Lee,Myeong Seok Kim,Jeong-Hwa Kang,Seung-Oh Hur,Soon Ik Kwon 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.4
This study aimed to identify the changing trends in the agricultural water quality of the major watersheds in Jeonnam Province over a 10-year period ranging from 2007 to 2016. The results of water quality analysis of the study sites revealed that the mean Chemical Oxygen Demand in April, July, and October was 3.20, 3.04, and 2.37 mg L<SUP>-1</SUP>, respectively, with the median values being 2.85, 2.84, and 1.96 mg L<SUP>-1</SUP>, respectively. The mean values of EC (Electrical Conductivity) in April, July, and October were 0.15, 0.15, and 0.17 dS m<SUP>-1</SUP>, respectively. The mean EC values were lower in April and slightly higher in October, and there was no yearly fluctuation. The mean and median values of the T-N (Total Nitrogen) content were 3.41 mg L<SUP>-1</SUP> and 3.18 mgL<SUP>-1</SUP>, respectively. A large deviation in the T-N content was only observed in April 2009 and July 2015. The mean and median values of the T-P (Total Phosphorous) content were 0.09 mg L<SUP>-1</SUP> and 0.05 mg L<SUP>-1</SUP>, respectively. No fluctuations were observed in the T-P content in the months of April, July, and October, during the study period, with the exception of July 2016 and October 2016.
Clinical Significance of F-18 FP-CIT Dual Time Point PET Imaging in Idiopathic Parkinson's Disease
Oh, Jin-Kyoung,Yoo, Ik-Dong,Seo, Ye-Young,Chung, Yong-An,Yoo, Ie-Ryung,Kim, Sung-Hoon,Song, In-Uk The Korea Society of Nuclear Medicine 2011 핵의학 분자영상 Vol.45 No.4
Purpose The purpose of this study was to investigate the diagnostic value of dual time point F-18 FP-CIT PET imaging in idiopathic Parkinson's disease (PD). Materials and Methods Twenty-four patients with PD (mean age 69.6) and 18 healthy people (mean age 70.26) underwent two sequential PET/CT scans (dual time point imaging) at 90 and 210 min after F-18 FPCIT injection. Tracer activity of region of interest was measured in the caudate, putamen and a reference region in the brain from both time points. The outcome parameter was the striatooccipital ratio (SOR). Normal SOR values were obtained in the control group. The percent change in tracer activity between 90- and 210- min images was calculated. The SOR values and the percent change in tracer activity were compared between the patients and healthy control group. Results The SOR values for the caudate, anterior and posterior putamen at both 90- and 210-min images were significantly reduced in the patients with PD. The lowest P value was obtained for the anterior and posterior putamen (p<0.001) at both time points. There were significant differences of the percent change in tracer activity for the anterior and posterior putamen in the two groups (p=0.01). Conclusions F-18 FP-CIT PET scans at 90 and 210 min after injection are both able to diagnose PD. Therefore, the 90-min image by itself is sufficient for diagnosing PD.