• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.949-965
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• 2023

In this study, we propose a method to monitor the surface area of agricultural reservoirs in South Korea using Sentinel-1 synthetic aperture radar images and the deep learning model, Swin Transformer. Utilizing the Google Earth Engine platform, datasets from 2017 to 2021 were constructed for seven agricultural reservoirs, categorized into 700 K-ton, 900 K-ton, and 1.5 M-ton capacities. For four of the reservoirs, a total of 1,283 images were used for model training through shuffling and 5-fold cross-validation techniques. Upon evaluation, the Swin Transformer Large model, configured with a window size of 12, demonstrated superior semantic segmentation performance, showing an average accuracy of 99.54% and a mean intersection over union (mIoU) of 95.15% for all folds. When the best-performing model was applied to the datasets of the remaining three reservoirsfor validation, it achieved an accuracy of over 99% and mIoU of over 94% for all reservoirs. These results indicate that the Swin Transformer model can effectively monitor the surface area of agricultural reservoirs in South Korea.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.45-59
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• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Journal of Chest Surgery
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• v.38 no.12 s.257
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• pp.821-827
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• 2005

Background: Hemodilution after priming of the cardiopulmonary bypass is known to increase the possibility of bleeding and homologous transfusion in adult cardiac surgery. We investigated the effects of retrograde autologous priming (RAP) to see whether it would decrease postoperative bleeding and homologous transfusion. Material and Method: We retrospectively reviewed 34 patients wpho underwent RAP and 46 patients who did not. Retrograde autologous priming consisted of arterial lire drainage, venous reservoir and oxygenator drainage and venous line drainage. We compared the amount of priming solution and RAP volume, perioperative hematocrit, postoperative bleeding and transfusion requirements in the two groups. Resuit: Mean withdrawal volume in RAP group was 613.5$\pm$160.6 mL and initial priming volume was 1381.9$\pm$37.2 mL. Hemoatocrits ($\%$) in RAP and control groups were 25.0$\pm$3.7 vs 20.9$\pm$3.6 (5 minutes after CPB), 25.9$\pm$3.7 vs 22.5$\pm$3.6 (30 minutes after CPB), 25.9$\pm$3.4 vs 23.8$\pm$2.8 (60 minutes after CPB), 31.9$\pm$3.9 vs 31.5$\pm$4.5 (postoperative 1 hour), 32.4$\pm$4.4 vs 32.1$\pm$4.5 (postoperative 6 hours), 33.4$\pm$5.0 vs 31.7$\pm$5.1 (postoperative 1 day)[repeated measures ANOVA, p < 0.05]. Chest tube drainages (mL) in the two groups were 357.2$\pm$177.1 vs 411.7$\pm$279.5 (postoperative 6 hours), 599.4$\pm$145.6 vs 678.8$\pm$256.4 (postoperative 24 hours)[t-test, p < 0.05]. Homologous transfusion was performed in 7 out of 34 patients in RAP group (20.6$\%$), and 16 out of 46 (34.8$\%$) in control group (p < 0.05). Conclusion: This study suggests that the effects of reducing the priming volume during cardiopulmonary bypass may result in lesser bleeding and homologous transfusion. Retrograde autologous priming would be used to reduce postoperative bleeding and chance of transfusion after adult cardiac surgery.

• Economic and Environmental Geology
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• v.48 no.4
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• pp.301-312
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• 2015

A commercial gas field was found in the southwestern continental shelf of the Ulleung Basin, East Sea in the late 1990s. To develop additional gas field, an exploration well was drilled through the coarse infill of submarine canyon near the gas field, but it was uneconomic to develop hydrocarbons. Using newly acquired deep seismic reflection and previous well data, we have identified additional geological structure which has hydrocarbon potentials below submarine canyons in the southwestern margin of the basin. Based on the interpretation of the deep seismic reflection and well data, the sequences of the study area can be classified into the syn-rift megasequence(MS1), post-rift megasequence(MS2), syn-compressional megasequence(MS3), and post-compressional megasequence(MS4) in relation to the tectonic events. MS1, deposited simultaneously with the basin formation before the middle Miocene, is characterized by chaotic seismic facies with low- to moderate-amplitude and low frequency reflections. MS2 comprises laterally continuous, low- to moderate-amplitude reflections, showing progradational stacking patterns due to high rates of sediment supply during basin expansion in the middle Miocene. MS3 is mainly composed of continuous reflections with high amplitude and moderate- to high-frequency which are interpreted as coarse-grained sediments. The coarse-grained sediments of MS3 sequence is widely truncated by several submarine canyons which filled with fine-grained sediment of MS4 to form a stratigraphic trap of hydrocarbon. Therefore, the reservoir and seal of the hydrocarbon trap in the study area are coarse-grained sediment of MS3 and submarine canyon filled with fine-grained sediment of MS4, respectively. A flat-spot seismic anomaly, which may indicate the presence of hydrocarbon, is observed within the stratigraphic trap.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.465-473
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• 2016

This study was carried out to evaluate restoration process of a few wetlands in the National Institute of Ecology (NIE). Wetlands were composed of the former rice paddies that passive restoration was led through only natural process and by creating waterway, and an ecological pond, a reservoir that restorative treatment was practiced. As the result of analysis on landscape change in the current wetland space, existing wetland in NIE was usually from the former rice field and some parts were from the residential area or forest. Change of species composition was progressed from crops or ruderals resistant to human interferences to plant species, which has removed artificially for cultivation and grow usually in the typical wetland. Both species diversity and occurrence of exotic plants were the highest when restoration project is in progress and stages after and before restoration were followed. In an ecological pond that restorative treatment was done, vegetation introduced as riparian buffer was established successfully and thereby it was expected that it could contribute to buffer environmental stress comming from the outside. Synthesized the above mentioned results, change of wetland vegetation established in NIE resembled the typical trend of early successional stage occurring in the abandoned rice paddy and consequently, it was estimated that successful restoration is under progress. Restoration under progress in an ecological pond where artificial aid in the least level was added, could be evaluated in successful as well. In particular, successful establishment of buffering vegetation, which can play diverse ecological functions, could be evaluated as significant restoration effect. But adaptive management to improve ecological quality for the section that buffering vegetation is insufficient, is required.

• Applied Microscopy
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• v.39 no.2
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• pp.167-173
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• 2009

Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in rodents and other mammals, including man. Rat species of the genus Rattus are main primary host and rates of genus Rattus of up to 100% have been reported. Infection to reservoir and other mammalian hosts occur incidentally due to ingestion of water or food contaminated with C. hepatica embryonated eggs. The worms mature exclusively inside the liver, but they die and disassemble soon after egg spawning in rats. Dead worms and their eggs cause immune response of focal necrosis and inflammation within the liver. C. hepatica adult with a thin and long body is similar to capillary. The members of Order Trichurida are characterized by having a stichosome and the bacillary bands in front of the body. As already mentioned, the adult C. hepatica residesin the liver, where it deposits groups of eggs, and finally die in the encapsulated tissue of the liver. They produce eggs that elicit a marked granulomatous reaction that eventually destroy the worms. And the adult worms were mixed with eggs. So the complete isolation of the worm and observation of intact ultrastructure is very difficult. In this study, integument structure of C. hepatica isolated from the liver of mouse at 7 weeks after inoculation of embryonated eggs were observed with scanning and transmission electron microscopy. As a results, body length of isolated C. hepatica was about 99 mm. Cuticle, bacillary band and bacillary pore were obtained in the integument of worm. Bacillary pore across cuticular surface of the worm were observed. According to the existence of cap material, external forms of bacillary pore can be divided into three types such as flat, ingression, and ingression with the cap material type. The complete isolation of the worm and observation of ultrastructure of integument will provide the fundamental data which is important in the nematode research including C. hepatica.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.115-128
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• 2008

Various human activities such as the Urbanization and Industrialization are estimated the main factors to pollute the stream. Now days, numerous studies are carried out for managing non-point sources which have un-effect on water quality of streams by land-use and livestock. In case of Korea, a matter of concern that the management of Pal dang reservoir - the main water resources of the national capital region - has been occurring. Especially, large-scale constructed-wetlands are planned and constructed at the end of Kyoung-an stream. Additionally a lot of sewage treatment plants are newly installed and extended in this watershed. According to these efforts, water quality of Kyoung-an stream is predicted that would be improved. But the more detail and scientific analysis should be carried out for the water quality improvement, because, existing water quality improvement projects are not involved to analyze root of water quality deterioration and improvement plans. Therefore, this study aims to select suitable areas for constructed-wetlands and to calculate size of the constructed-wetlands for water quality improvement in Kyoung-an stream through the geographical pollutant distribution analysis and land-use pattern analysis by high resolution satellite image and suitable area analysis of constructed-wetlands by GIS(Geographic information system). The progress of this study is (1) to select maximum pollutant loaded area by geographical analysis based on water quality data, (2) to analyze land-use patterns using high resolution satellite image, (3) to select suitable areas of constructed-wetlands, (4) to calculate area and volume of chosen constructed-wetlands using GIS. Basically, sizes of constructed-wetlands are induced through the constructed-wetlands design index based on treatment ratio(provided by Korea Water Resources Corporation). As a result of this study, two areas are selected to construct constructed-wetlands. One of the area was $127,586m^2$ near by Yong-in sewage treatment plant, and the other area was $1,647m^2$ near by Ju-buk stream and Dae-dae stream.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.39-50
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• 2019

This study aims to assess the influence of climate change on the hydrological cycle at a basin level in North Korea. The selected model for this study is MRI-CGCM 3, the one used for the Coupled Model Intercomparison Project Phase 5 (CMIP5). Moreover, this study adopted the Spatial Disaggregation-Quantile Delta Mapping (SDQDM), which is one of the stochastic downscaling techniques, to conduct the bias correction for climate change scenarios. The comparison between the preapplication and postapplication of the SDQDM supported the study's review on the technique's validity. In addition, as this study determined the influence of climate change on the hydrological cycle, it also observed the runoff in North Korea. In predicting such influence, parameters of a runoff model used for the analysis should be optimized. However, North Korea is classified as an ungauged region for its political characteristics, and it was difficult to collect the country's runoff observation data. Hence, the study selected 16 basins with secured high-quality runoff data, and the M-RAT model's optimized parameters were calculated. The study also analyzed the correlation among variables for basin characteristics to consider multicollinearity. Then, based on a phased regression analysis, the study developed an equation to calculate parameters for ungauged basin areas. To verify the equation, the study assumed the Osipcheon River, Namdaecheon Stream, Yongdang Reservoir, and Yonggang Stream as ungauged basin areas and conducted cross-validation. As a result, for all the four basin areas, high efficiency was confirmed with the efficiency coefficients of 0.8 or higher. The study used climate change scenarios and parameters of the estimated runoff model to assess the changes in hydrological cycle processes at a basin level from climate change in the Amnokgang River of North Korea. The results showed that climate change would lead to an increase in precipitation, and the corresponding rise in temperature is predicted to cause elevating evapotranspiration. However, it was found that the storage capacity in the basin decreased. The result of the analysis on flow duration indicated a decrease in flow on the 95th day; an increase in the drought flow during the periods of Future 1 and Future 2; and an increase in both flows for the period of Future 3.

• Economic and Environmental Geology
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• v.45 no.4
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• pp.351-363
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• 2012

In order to develop the evaluation techniques for the potential sulfide ore reserves, the relationships between the modal vol.%, grain sizes and textural characteristics of the constituent minerals (e.g., sulfides, oxides and skarn minerals) and the Spectral Induced Polarization (SIP) phase differences are examined for the nine rock cores collected from the Gagok Pb-Zn skarn deposit. The Gagok Pb-Zn skarn deposit occurs mainly along the intrusive contact between the Cretaceous granitic rocks and Cambrian Myobong slate and Pungchon limestone. The nine rock cores have been grouped into three showing distinctive SIP phase differences: the highest (Group I), intermediate (Group II) and lowest (Group III). In relation with the modal vol.% of minerals, Group I is characterized by higher pyrrhotite (25-38 vol.%) and amphibole (40-55 vol.%); Group II by intermediate pyrrhotite (7-13 vol.%) and higher garnet (44-68 vol.%); and lower pyrrhotite (1-7 vol.%) and higher pyroxene (24-66 vol.%) stand for Group III. Furthermore, the grains of all the major constituent minerals become smaller from Group I (<5 mm) through Group II (<2.5 mm) to Group III (<1.6 mm). In particular, the pyrrhotite contents and their grain sizes show logarithmic correlation with the SIP phase differences, Although we present here the results solely from nine samples, the systematic interrelations especially for pyrrhotite indicate the potential ability of SIP measurements as a new mine-evaluation technique for the sulfide ore reservoir.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.2 s.31
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• pp.59-66
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• 2004

This paper presents a novel fabrication process for a tapered hollow metallic microneedle array using backside exposure of SU-8, and analytic solutions of critical buckling of a tapered hollow microneedle. An SU-8 meta was formed on a Pyrex glass substrate and another SU-8 layer, which was spun on top of the SU-8 mesa, was exposed through the backside of the glass substrate. An array of SU-8 tapered pillar structures. with angles in the range of $3.1^{\circ}{\sim}5^{\circ}$ was formed on top of the SU-8 mesa. Conformal electrodeposition of metal was carried out followed by a mechanical polishing using a pianarizing polymeric layer. All organic layers were then removed to create a metallic hollow microneedle array with a fluidic reservoir on the backside. Both $200{\mu}m\;and\;400{\mu}m$ tall, 10 by 10 arrays of metallic microneedles with inner diameters of the tip in the range of $33.6{\sim}101\;{\mu}m$ and wall thickness of $10{\mu}m\;-\;20{\mu}m$ were fabricated. Analytic solutions of the critical buckling of arbitrary-angled truncated cone-shaped columns are also presented. It was found that a single $400{\mu}m$ tall hollow cylindrical microneedle made of electroplated nickel with a wall thickness of $20{\mu}m$, a tapered angle of $3.08^{\circ}$ and a tip inner diameter of $33.6{\mu}m$ has a critical buckling force of 1.8 N. This analytic solution can be used for square or rectangular cross-sectioned column structures with proper modifications.