Korean Journal of Agricultural and Forest Meteorology
/
v.3
no.4
/
pp.215-219
/
2001
Land surface parameterization schemes for atmospheric models as well as decision support tools for ecosystem management require a frequent updating of land cover classification data for regional to global scales. Rice paddies have not been treated independently from other agricultural land classes in many classification systems, despite their atmospheric and ecological significance. A simple but improved method over conventional land cover classification schemes for rice paddy is suggested. Normalized difference vegetation index (NDVI) was calculated for the land area of South Korea at a 1km by 1 km resolution from the visible and the near-infrared channel reflectances of NOAA-AVHRR (Advanced Very High Resolution Radiometer). Monthly composite images of daily maximum NDVI were prepared for May and August, and used to classify 4 major land cover classes : urban, farmland, forests and water body. Among the pixels classified as "forests" in August, those classified as "water body" in May were assigned a "rice paddy" class. The distribution pattern of "rice paddy" pixels was very similar to the reported rice acreage of 1,455 Myons, which is the smallest administrative land unit in Korea. The correlation coefficient between the estimated and the reported acreage of Myons was 0.7, while 0.5 was calculated from the USGS classification.calculated from the USGS classification.
Four sites and one site were used to analyze fish diversity at the water systems of the Sineun reservoir and the Jeonchon reservoir, respectively. The field experiments were conducted to test the density dependence that could lead to population regulation by artificial inferences and environmental changes. We examined the effects of environmental factors on fish densities using SMATR freeware. It was estimated to be reduced to the density effect at four sites in 2012. Shannon-Weaver indices of the diversity (H’) of the Sineun reservoir were similar to those of the Jeonchon reservoir. Species diversity was in a range of 0.645 to 2.105. The H’ value of the upper region was higher than those of middle and low regions were, and values of richness were lower in downstream than upstream. Using the maximum likelihood solution for the removal estimators of two low regions of the river stations, the estimated migration probabilities from the resident fish to the migrated fish for five species (Cyprinus cuvieri, Carassius auratus, Pseudorasbora parva, Misgurnus mizolepis, and Oryzias latipes) had a mean of 0.623. Especially, migration probabilities from the Jeonchon reservoir to the Sineun reservoir for five species were high (a mean of 0.681). The period of migration was suggested to be about one month because of short geographical distances (50 m). We found no significant difference between the three categories in the distribution of the other four species, indicating the species probability was similar among stations.
Due to the growth in industrialization, potential hazards in subsurface environments are becoming increasingly significant. The extraction of the contaminant from the soil and movement of the water are restricted due to the low permeability and adsorption characteristics of the reclaimed soils. There are a number of approaches to in-situ remediation that are used in contaminated sites for removing contaminants. These include soil flushing, dual phase extraction, and soil vapor extraction. Among these techniques, soil flushing was the focus of the investigation in this paper. Incorporated technique with PVDs has been used for dewatering from fine-grained soils for the purpose of ground improvement by means of prefabricated vertical drain systems. The laboratory model tests were performed by using the flushing tracer solutions for silty soils and recorded the tracer concentration changes with the elapsed time and flow rates. The modeling was intended to predict the effectiveness and time dependence of the remediation process. Modeling has been performed on the extraction, considering tracer concentration and laboratory model test characteristics. The computer model used herein are SEEP/W and CTRAN/W, this 2-D finite element program allows for modeling to determine hydraulic head and pore water pressure distribution, efficiency of remediation for the subsurface environment. It is concluded that the coefficient of permeability of contaminated soil is related with vertical velocity and extracted flow rate. The vertical velocity and extracted flow rate have an effect on dispersivity and finally are played an important role in-situ soil remediation.
The objective of this study was to investigate the treatment efficiency, kinetics, and morphological characteristics of biofilm in upflow $Biobead^{(R)}$ process, a kind of biological aerated filter(BAF). The $Biobead^{(R)}$ system showed high removal rates of $COD_{Mn}$(76~83%), $BOD_5$(67~88%) and SS(71~91%) for food wastewater with high salt concentration ($>4,000mg/{\ell}$) under short reaction times(2~3hrs). Even at aerobic condition, the system had high treatment efficiency for both T-N (51~63%) and T-P(62~81%). The removal kinetics of $COD_{Mn}$, $BOD_5$, T-N, T-P, and $Cl^-$ in the $Biobead^{(R)}$ system showed a plug-flow pattern with reaction rate constants($hr^{-1}$) of 0.58, 0.63, 0,30, 0.48, and 0.38 respectively. A backwashing process to remove excess biomass and filtered solids was needed at least once during 22-hour operation at $0.5kg\;BOD\;m^{-3}{\cdot}d^{-1}$ loading. At the higher loading($1.0kg\;BOD\;m^{-3}{\cdot}d^{-1}$) the backwashing interval was shorten by 8 hours. The COD, BOD, T-N, and T-P were removed from 43 to 66% only by aerobic biodegradation. The SS was removed over 70% by the filtering of $Biobead^{(R)}$ media in the treatment system. The first one of three serial Biobead reactors showed the highest removal values for $COD_{\alpha}$(52.3%), $COD_{Mn}$(38.8%), BOD(62.5%), and T-N(40.0%). The SS and T-P had the highest removal values(47.5% and 29.2%) at the second one of the serial reactors. The biofilm had non-homogeneous spatial distribution and the colonies were embedded in the sunk area of the Biobead. The thickness of the biofilm was very thin ($5.0{\sim}29.4{\mu}m$) compared to the biofilm thickness($200{\sim}300{\mu}m$) used in other BAF systems.
Park, So-Yeon;Park, Jong Min;Choi, Chang Heon;Chun, Minsoo;Kim, Jung-in
Progress in Medical Physics
/
v.27
no.4
/
pp.180-188
/
2016
Acuros XB advanced dose calculation algorithm (AXB, Varian Medical Systems, Palo Alto, CA) has been released recently and provided the advantages of speed and accuracy for dose calculation. For clinical use, it is important to investigate the dosimetric performance of AXB compared to the calculation algorithm of the previous version, Anisotropic Analytical Algorithm (AAA, Varian Medical Systems, Palo Alto, CA). Ten volumetric modulated arc therapy (VMAT) plans for each of the following cases were included: head and neck (H&N), prostate, spine, and lung. The spine and lung cases were treated with stereotactic body radiation therapy (SBRT) technique. For all cases, the dose distributions were calculated using AAA and two dose reporting modes in AXB (dose-to-water, $AXB_w$, and dose-to-medium, $AXB_m$) with same plan parameters. For dosimetric evaluation, the dose-volumetric parameters were calculated for each planning target volume (PTV) and interested normal organs. The differences between AAA and AXB were statistically calculated with paired t-test. As a general trend, $AXB_w$ and $AXB_m$ showed dose underestimation as compared with AAA, which did not exceed within -3.5% and -4.5%, respectively. The maximum dose of PTV calculated by $AXB_w$ and $AXB_m$ was tended to be overestimated with the relative dose difference ranged from 1.6% to 4.6% for all cases. The absolute mean values of the relative dose differences were $1.1{\pm}1.2%$ and $2.0{\pm}1.2%$ when comparing between AAA and $AXB_w$, and AAA and $AXB_m$, respectively. For almost dose-volumetric parameters of PTV, the relative dose differences are statistically significant while there are no statistical significance for normal tissues. Both $AXB_w$ and $AXB_m$ was tended to underestimate dose for PTV and normal tissues compared to AAA. For analyzing two dose reporting modes in AXB, the dose distribution calculated by $AXB_w$ was similar to those of AAA when comparing the dose distributions between AAA and $AXB_m$.
Kim, So-Hyun;Kim, Min-Woo;Lee, Eun-Kyung;Lee, Jung-Woon
Journal of the Korean Institute of Gas
/
v.22
no.6
/
pp.76-89
/
2018
The distribution of the combined heat and power system is active as a solution to the instability of energy supply and environmental pollution caused by continuous industrial development. In Korea, the safety standards for combined heat and power system using a gas engine are insufficient therefore the study on this is needed. In this study, the safety performance and structural/material assessment items of domestic and international standards applied to the combined heat and power system were analyzed to carry out a standardization study on safety performance applicable to 20 kW gas engine combined heat and power system. In addition, the safety performance assessment (plan) of the gas engine combined heat and power system was derived by performing risk analysis and risk assessment using HAZOP. Assessment items include engine ignition systems related to safety performance, piping tight performance, watering and temperature rise performance, combustion performance, electrical efficiency, thermal efficiency, overall efficiency and humidity performance. Gas and water pipes, gas control and shut-off valves, durability, heat resistance, and cold resistance of metal or non-metallic materials related to the structure and materials of the gas engine combined heat and power systems.
Journal of the Korean Society of Marine Environment & Safety
/
v.29
no.2
/
pp.139-146
/
2023
Maritime object detection systems, which detects small maritime obstacles such as fish farm buoys and visualizes distance and direction, is equipped with a 3-axis gimbal to compensate for errors caused by hull motion, but there is a limit to distance error corrections necessitated by the vertical movement of the camera and the maritime object due to wave motions. Therefore, in this study, the distance error of maritime object detection systems caused by the movement of the water surface according to the external environment is analyzed and corrected using average filter and moving average filter. Random numbers following a Gaussian standard normal distribution were added to or subtracted from the image coordinates to reproduce the rise or fall of the buoy under irregular waves. The distance calculated according to the change of image coordinates, the predicted distance through the average filter and the moving average filter, and the actual distance measured by laser distance meter were compared. In phases 1 and 2, the error rate increased to a maximum of 98.5% due to the changes of image coordinates due to irregular waves, but the error rate decreased to 16.3% with the moving average filter. This error correction capability was better than with the average filter, but there was a limit due to failure to respond to the distance change. Therefore, it is considered that use of the moving average filter to correct the distance error of the maritime object detection system will enhance responses to the real-time distance change and greatly improve the error rate.
Korean Journal of Agricultural and Forest Meteorology
/
v.12
no.4
/
pp.307-316
/
2010
Complex terrain refers to irregular surface properties of the earth that influence gradients in climate, lateral transfer of materials, landscape distribution in soils properties, habitat selection of organisms, and via human preferences, the patterning in development of land use. Complex terrain of mountainous areas represents ca. 20% of the Earth's terrestrial surface; and such regions provide fresh water to at least half of humankind. Most major river systems originate in such terrain, and their resources are often associated with socio-economic competition and political disputes. The goals of the TERRECO-IRTG focus on building a bridge between ecosystem understanding in complex terrain and spatial assessments of ecosystem performance with respect to derived ecosystem services. More specifically, a coordinated assessment framework will be developed from landscape to regional scale applications to quantify trade-offs and will be applied to determine how shifts in climate and land use in complex terrain influence naturally derived ecosystem services. Within the scope of TERRECO, the abiotic and biotic studies of water yield and quality, production and biodiversity, soil processing of materials and trace gas emissions in complex terrain are merged. There is a need to quantitatively understand 1) the ecosystem services derived in regions of complex terrain, 2) the process regulation occurred to maintain those services, and 3) the sensitivities defining thresholds critical in stability of these systems. The TERRECO-IRTG is dedicated to joint study of ecosystems in complex terrain from landscape to regional scales. Our objectives are to reveal the spatial patterns in driving variables of essential ecosystem processes involved in ecosystem services of complex terrain region and hence, to evaluate the resulting ecosystem services, and further to provide new tools for understanding and managing such areas.
In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH3/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg-1/2 m-1/2 S-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg-1/2 m-1/2 S-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.
Lee, Hee-Jin;Nam, Won-Ho;Jason A. Otkin;Yafang Zhong;Xiang Zhang;Mark D. Svoboda
Journal of Korea Water Resources Association
/
v.57
no.8
/
pp.509-518
/
2024
Flash drought is a rapid-onset drought that occurs rapidly over a short period due to abrupt changes in meteorological and environmental factors. In this study, we utilized satellite-based soil moisture product from the Advanced Microwave Scanning Radiometer-2(AMSR2) ascending X-band to calculate the weekly Flash Drought Intensity Index (FDII). We also analyzed the characteristics of flash droughts on the Korean Peninsula over a 10-year period from 2013 to 2022. The analysis of monthly spatial distribution patterns of the irrigation period across the Korean Peninsula revealed significant variations. In North Korea (NK), a substantial increase in the rate of intensification (FD_INT) was observed due to the rapid depletion of soil moisture, whereas South Korea (SK) experienced a significant increase in drought severity (DRO_SEV). Additionally, regional time series analysis revealed that both FD_INT and DRO_SEV were significantly high in the Gangwon province of both NK and SK. The estimation of probability density by region revealed a clear difference in FD_INT between NK and SK, with SK showing a higher probability of severe drought occurrence primarily due to the high values of DRO_SEV. As a result, it is inferred that the occurrence frequency and damage of flash droughts in NK are higher than those in SK, as indicated by the higher density of large FDII values in the NK region. We analyzed the correlation between DRO_SEV and the Evaporative Stress Index (ESI) across the Korean Peninsula and confirmed a positive correlation ranging from 0.4 to 0.6. It is concluded that analyzing overall drought conditions through the average drought severity holds high utility. These findings are expected to contribute to understanding the characteristics of flash droughts on the Korean Peninsula and formulating post-event response plans.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.