• 환경생물
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• 제18권1호
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• pp.77-93
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• 2000

시아해의 수질환경과 식물플랑크톤 생물량의 계절변동 특성 및 식물플랑크톤 생물량변동에 영향을 미치는 환경요인을 파악하기 위해 1995년 2월,4월,7월과 10월 4회에 걸쳐 계절별로 23개 관측점의 표층과 저층 해수를 대상으로 현장조사를 실시하였다. 결과, 시아해는 2월에 최저수온, 8월에 최고 수온을 나타내나, 염분은 6, 7월에 높고 겨울에 낮은 특성을 나타내었으며, 연중 빠른 유속과 조석혼합 등으로 수층 간 혼합된 양상과 매우 낮은 투명도를 나타내고 있었다. 영양염류 중 질소는 여름을 제외하고는 비교적 높은 값을 나타내며, 인은 연중 0.5$\mu\textrm{g}$ㆍat./l내외의 값을 보이고 있는 반면, 규소는 봄철 규조류 대발생시를 제외하고는 연중 높은 농도를 유지하고 있었다. Chl-a는 연중 2$\mu\textrm{g}$/l 이상의 높은 값을 나타내고 있으며, 특히 규조류의 대발생이 보여지는 봄철에 높은 값을 나타내었다. 다만, 연중 높은 생물량은 생물의 성장과 활성에 의하기보다는 조석혼합 등에 의해 해저표층퇴적물에 침강된 표영생태계 중의 생물량 상당부분이 수중으로 재 부유한 결과로 보여져, 높은 부유물질 등 제한된 광 조건으로 시아해 식물플랑크톤 생물활성은 그다지 높지 않을 것으로 추정되었다. 기초생산을 제한하는 영양염은 시아해 북쪽해역에서는 인에 의해, 남쪽해역에서는 질소에 의해 지배되고 있는 것으로 나타났으며, 겨울철은 인의 존재량에 비해 질소가 과잉으로 존재하는 것으로 나타났다. 그리고 규소는 봄철 규조의 대발생시를 제외하고는 식물플랑크톤 군집에 크게 영향을 주지 앓는 것으로 나타났다. 또한, 영양염류 중 규소는 담수 등 복잡한 주변 수괴의 유입에 의존하는 비율이 높고, 질소는 여름에는 담수 유입에 의존하나 시기에 따라서는 저층 해수의 공급에 의존하는 것으로 나타났다. 인은 담수유입에 의한 부분보다 저층 해수 및 주변 수괴로부터 유입하는 비율이 높은 것으로 판단되었다. 시아해의 식물플랑크톤에 영향을 미치는 환경요인은 시간과 공간에 따라 다르게 나타나고 있으며, 여름철 극심한 질소의 부족이나 봄철 규조 대발생시의 규산염 고갈 등을 제외하면 영양염류보다도 높은 부유물질, 즉 광량 등 물리학적 요인에 의해 영향을 받는 것으로 판단되었다.

• Ocean and Polar Research
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• 제31권1호
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• pp.63-70
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• 2009

Eutrophicated water fed through Mankyeong River and Dongjin River into the new Saemankeum Lakemight seriously affect the water quality and phytoplankton community in the lake. To obtain control reference data for the later studies on environmental changes due to the construction of the Saemankeum Sea Wall, we performed a monthly investigation on the physico-chemical properties of the water and phytoplankton community at 3 stations in the Mankyeong River Estuary over 14 months starting from September 1999. Water temperature ranged from $0.3{\sim}32.9^{\circ}C$ due to the typical seasonal variations in temperate on the coasts and salinity exhibited a wide annual range of $0.2{\sim}33.7$ psu along with regular and huge hourly variations according to tidal cycles. Inorganic nutrients were supplied from rivers to the monitoring station and the whole lake. The average concentration of total-N, $6.99\;mg{\cdot}l^{-1}$, was higher than the water quality for agricultural use with peak values occurring in winter. Species composition showed a seasonal succession pattern, where a high diversity was observedin summer and autumn and vice versa in winter. Hourly variations of water properties in the "Mankyeong bridge" Station were quite regular and well in accordance with the daily tidal cycles. The different degree of sea water intrusion during the flood tide at each of the 3 stations exhibited a different range and variation pattern of water temperature and salinity throughout a day. Hourly changes in species composition were in harmony with the daily tidal cycles, resulting in extremely variable spatio-temporal variation.

• Asian Journal of Atmospheric Environment
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• 제6권2호
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• pp.127-135
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• 2012

Urbanization has led to a reduction in green spaces and thus transformed the spatial pattern of urban land use. An increase in air temperature directly affects forest vegetation, phenology, and biodiversity in urban areas. In this paper, we analyze the changing land use patterns and urban heat distribution (UHD) in Seoul on the basis of a spatial assessment. It is necessary to monitor and assess the functions of green spaces in order to understand the changes in the green space. In addition, we estimated the influence of green space on urban temperature using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) imagery and climatic data. Results of the assessment showed that UHD differences cause differences in temperature variation and the spatial extent of temperature reducing effects due to urban green space. The ratio of urban heat area to green space cooling area increases rapidly with increasing distance from a green space boundary. This shows that urban green space plays an important role for mitigating urban heating in central areas. This study demonstrated the importance of green space by characterizing the spatiotemporal variations in temperature associated with urban green spaces.

• 한국환경과학회지
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• 제24권4호
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• pp.471-480
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• 2015

Hydrologic component analysis was conducted to investigate water budget characteristics the Oedocheon watershed, Jeju Island. For this purpose, integrated SWAT-MODFLOW model was applied to this watershed for continuous surface water-groundwater modeling. Pasture and forest-deciduous are the major land use types and these affect general hydrologic component ratio. The spatio-temporal groundwater recharge can be obtained from SWAT and then distributed groundwater recharge can be reproduced by MODFLOW. The groundwater level variation was simulated with distributed groundwater pumping data. The water budget in this watershed was compared with the previous estimated result by Jeju-Do(2013). As this result considered discharge to the coastal side, the discrepancy was found. However, it was found that the overall tendency of both analyses were similar.

• Wind and Structures
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• 제25권3호
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• pp.301-328
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• 2017

Multivariate fluctuating pressures acting on a 2:1 rectangular section (2-D) with dimensions of 9 cm by 4.5 cm has been studied using wind tunnel experiments under uniform and smooth flow condition for various angles of wind incidence. Based on the variation of mean pressure coefficient distributions along the circumference of the rectangular section with angle of wind incidence, and with the aid of skin friction coefficients, three distinct flow regimes with two transition regimes have been identified. Further, variations of mean drag and lift coefficients, Strouhal number with angles of wind incidence have been studied. The applicability of Universal Strouhal number based on vortex street similarity of wakes in bluff bodies to the 2:1 rectangular section has been studied for different angles of wind incidence. The spatio-temporal correlation features of the measured pressure data have been studied using Proper Orthogonal Decomposition (POD) technique. The contribution of individual POD modes to the aerodynamic force components, viz, drag and lift, have been studied. It has been demonstrated that individual POD modes can be associated to different physical phenomena, which contribute to the overall aerodynamic forces.

• 대한인간공학회지
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• 제27권3호
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• pp.93-101
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• 2008

Wedged soles and rocker soles are widespread shoe designs used to prevent the disorders and reduce the pain of the lower extremity caused by arthritis or diabetic feet. In this study, the effect of a shoe with a laterally wedged sole and a rocker sole simultaneously was analyzed on the kinematics and kinetics of the ankle joint during normal walking. Eight male participants without a history of lower extremity disorders were recruited. Each participant performed twenty walking cycles for each of three walking conditions: bare foot, wearing normal shoes and wearing shoes with laterally wedged rocker soles. The differences between the three walking conditions were statistically investigated including spatio-temporal variables, angular displacements, joint moments and ground reaction forces. The results showed that the laterally wedged rocker sole decreased the sagittal variation of angular displacements as well as the frontal/sagittal average moment on the ankle joints compared to the flat sole. In addition, the rate of angular displacements and loading decreased during the heel contact phase.

• 한국환경과학회지
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• 제25권11호
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• pp.1563-1573
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• 2016

The aim of this study was to evaluate the occurrence of vanadium in Jeju Island groundwater, focusing on the spatio-temporal patterns and geochemical controlling factors of vanadium. For this, we collected two sets of groundwater data: 1) concentrations of major constituents of 2,595 groundwater samples between 2008 and 2014 and 2) 258 groundwater samples between December 2006 and June 2008. The concentrations of groundwater vanadium were in the range of $0.2{\sim}71.0{\mu}g/L$ (average, $12.0{\mu}g/L$) and showed local enrichments without temporal/seasonal variation. This indicated that vanadium distribution was controlled by 1) the geochemical/mineralogical composition and dissolution processes of original materials (i.e., volcanic rock) and 2) the flow and chemical properties of groundwater. Vanadium concentration was significantly positively correlated with that of major ions ($Cl^-$, $Na^+$, and $K^+$) and trace metals (As, Cr, and Al), and with pH, but was negatively correlated with $NO_3-N$ concentration. The high concentrations of vanadium (>$15{\mu}g/L$) occurred in typically alkaline groundwater with high pH (${\geq}8.0$), indicating that a higher degree of water-rock interaction resulted in vanadium enrichment. Thus, higher concentrations of vanadium occurred in groundwater of $Na-Ca-HCO_3$, $Na-Mg-HCO_3$ and $Na-HCO_3$ types and were remarkably lower in groundwater of $Na-Ca-NO_3$(Cl) type that represented the influences from anthropogenic pollution.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1557-1561
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• 2014

Background: Breast cancer is the most frequently diagnosed cancer in women and estimating its relative risks and trends of incidence at the area-level is helpful for health policy makers. However, traditional methods of estimation which do not take spatial heterogeneity into account suffer from drawbacks and their results may be misleading, as the estimated maps of incidence vary dramatically in neighboring areas. Spatial methods have been proposed to overcome drawbacks of traditional methods by including spatial sources of variation in the model to produce smoother maps. Materials and Methods: In this study we analyzed the breast cancer data in Iran during 2004-2008. We used a method proposed to cover spatial and temporal effects simultaneously and their interactions to study trends of breast cancer incidence in Iran. Results: The results agree with previous studies but provide new information about two main issues regarding the trend of breast cancer in provinces of Iran. First, this model discovered provinces with high relative risks of breast cancer during the 5 years of the study. Second, new information was provided with respect to overall trend trends o. East-Azerbaijan, Golestan, North-Khorasan, and Khorasan-Razavi had the highest increases in rates of breast cancer incidence whilst Tehran, Isfahan, and Yazd had the highest incidence rates during 2004-2008. Conclusions: Using spatial methods can provide more accurate and detailed information about the incidence or prevalence of a disease. These models can specify provinces with different health priorities in terms of needs for therapy and drugs or demands for efficient education, screening, and preventive policy into action.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.371-384
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• 2019

Motion perception has been tremendously improved in neuroscience and computer vision. The baseline motion perception model is mediated by the dorsal visual pathway involving the cortex areas the primary visual cortex (V1) and the middle temporal (V5 or MT) visual area. However, few works have been done on the extension of neural models to improve the efficacy and robustness of motion perception of real sequences. To overcome shortcomings in situations, such as varying illumination and large displacement, an adaptive V1-MT motion perception (Ad-V1MTMP) algorithm enriched to deal with real sequences is proposed and analyzed. First, the total variation semi-norm model based on Gabor functions (TV-Gabor) for structure-texture decomposition is performed to manage the illumination and color changes. And then, we study the impact of image local context, which is processed in extra-striate visual areas II (V2), on spatial motion integration by MT neurons, and propose a V1-V2 method to extract the image contrast information at a given location. Furthermore, we take feedback inputs from V2 into account during the polling stage. To use the algorithm on natural scenes, finally, multi-scale approach has been used to handle the frequency range, and adaptive pyramidal decomposition and decomposed spatio-temporal filters have been used to diminish computational cost. Theoretical analysis and experimental results suggest the new Ad-V1MTMP algorithm which mimics human primary motion pathway has universal, effective and robust performance.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.477-493
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• 2020

고창 연안해역의 해양환경 및 식물플랑크톤 군집의 시·공간적 변동 특성을 파악하기 위해 2016년 여름에서 2017년 봄까지 4계절 16개 정점을 조사하였다. 분석 결과, 수온은 표층에서 2.1℃에서 34.5℃의 범위로 큰 계절 변화를 보였지만, 염분은 표층에서 31.14 psu에서 32.64 psu의 범위로, 계절 변화가 크지 않아, 연안해역 수형은 수온에 지배되었다. Chl-a 역시 봄 최솟값 0.58 ㎍ L^-1에서 여름 최댓값 10.5 ㎍L^-1의 범위로 겨울에 높고, 가을과 봄에 낮았고, 큰 계절 변화를 보였다. 식물플랑크톤 군집은 53속 86종으로 단순하였다. 표층 현존량은 가을 최솟값 2.2 cells mL^-1에서 여름 최댓값 689.2 cells mL^-1의 변화 폭으로 여름에 높고, 가을에 낮았으나, 가을은 다른 계절보다 한 자릿수가 이상 낮았다. 우점종은 연중 규조류에 지배되어, 표층은 여름이 Leptocylindrus danicus, Chaetoceros curvisetus Skeletonema costatum-ls, 가을은 Paralia sulcata, Eucampia zodiacus, 겨울은 S. costatum-ls, Thalasiosira nordenskioeldii, 그리고 봄은 S. costatum-ls, Asterionella glacialis가 우점하였다. 즉 고창 연안해역의 식물플랑크톤 군집은 다양성이 높지만, 연중 특정 종에 크게 지배되는 군집구조를 나타내었다. 주성분 분석 결과 고창 연안해역은 낮은 수심으로 복사열에 의해 쉽게 가열 및 냉각되며, 조석혼합 등 해수 혼합 특성으로 표층퇴적물의 재부유에 의한 영양염 공급으로 식물플랑크톤 시·공간 분포가 결정되었다.