• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.113-113
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• 2022

Salinity in surface waters is increasing around the world. Many factors, including increased water extraction, poor irrigation management, and sea-level rise, contribute to this change, and posing a threat to plant development and agricultural production. Seeds exposed to high salinity, have a lower probability of germinating and various physiological and biochemical effects. Salinity stress affects more than 20% of agricultural land and about 50% of irrigated land. In the current study, our objective is to identify the salt-tolerant peanut (Arachis hypogaea L.) Korean genotypes under salinity stress. Thus, two-week-old 19 diverse peanut Korean genotypes were exposed to 10 days of salinity (150 mM NaCl) stress. Based on the growth attributes investigation, Baekjung and Ahwon genotypes showed significantly higher shoot lengths compared to control plants. Whereas, the Sinpalwang genotype exhibited a significantly positive response for plant growth and reduced wilting symptoms compared to other genotypes. This study was able to find out peanut tolerant and sensitive genotypes for salt stress. These results may provide a good template for further salt-tolerant peanut cultivar improvement programs. Identified diverse salt-responsive genotypes can be utilized as source material in Korean breeding schemes for peanut crop improvement for salt and other abiotic stress tolerance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.277-281
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• 1997

The cell density changes of Vibrio mimicus K-1 in sea water and arkshell feeding it were examined at various temperature. The strain was suspended in sterilized sea water and storaged at experimental temperature $(5,\;10,\;15,\;20,\;and\;28^{\circ}C)$). At intervals of up to 10 days, aliquots of each suspension were plated onto BHI agar. At 5 and $10^{\circ}C$, the plate counts of V. mimicus K-1 showed a rapid decline, which 3s known to be a reault of this bacterium's entering into the viable but non culturable state. At 20 and $28^{\circ}C$, however, V. mimicus K-1 are stable over the 10 days experimental periods. V. mimicus K-1 was fed to arkshell, which was subsequently stored at temperatures ranging from 5 to $20^{\circ}C$ for 10 days. The samples of arkshell were homogenized and plated at intervals to determine the cell density of V. mimicus K-1 and total aerobic population of bacteria present. At 5 and $10^{\circ}C$, the numbers of V. mimicus K-1 in sea water rapid decreased over the 10 days experimental periods. However, little change of V. mimicus K-1 density was observed in shellstock arkshell at 5 and $10^{\circ}C$. While, V. mimicus K-1 density was decreased more rapidly to level below limit of dectection in shucked arkshell at same temperature. Incubation at the higher temperature $(20^{\circ}C)$ resulted in large increase in total aerobic bacterial number of shellstock arkshell. These results suggest that even with proper storage, indigenous levels of V. mimicus may remain sufficiently high in shellstock arkshell to produce infection in compromise hosts.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.128-136
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• 2011

To monitor and predict the change of coastal environment according to the construction of Saemangeum sea dyke and the development of land reclamation, we have done real-time and periodic ocean observation and numerical simulation since 2002. Saemangeum coastal environmental data can be largely classified to marine meteorology, ocean physics and circulation, water quality, marine geology and marine ecosystem and each part of data has been generated continuously and accumulated over about 10 years. The collected coastal environmental data are huge amounts of heterogeneous dataset and have some characteristics of multi-dimension, multivariate and spatio-temporal distribution. Thus the implementation of information system possible to data collection, processing, management and service is necessary. In this study, through the implementation of Saemangeum coastal environmental information system using geographic information system, it enables the integral data collection and management and the data querying and analysis of enormous and high-complexity data through the design of intuitive and effective web user interface and scientific data visualization using statistical graphs and thematic cartography. Furthermore, through the quantitative analysis of trend changed over long-term by the geo-spatial analysis with geo- processing, it's being used as a tool for provide a scientific basis for sustainable development and decision support in Saemangeum coast. Moreover, for the effective web-based information service, multi-level map cache, multi-layer architecture and geospatial database were implemented together.

• Journal of Korea Water Resources Association
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• v.50 no.2
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• pp.75-87
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• 2017

In recent decades, extreme events have been significantly increased over the Korean Peninsula due to climate variability and climate change. The potential changes in hydrologic cycle associated with the extreme events increase uncertainty in water resources planning and designing. For these reasons, a reliable changing point analysis is generally required to better understand regime changes in hydrologic time series at watershed scale. In this study, a hierarchical changing point analysis approach that can apply in a watershed scale is developed by combining the existing changing point analysis method and hierarchical Bayesian method. The proposed model was applied to the selected stations that have annual rainfall data longer than 40 years. The results showed that the proposed model can quantitatively detect the shift in precipitation in the middle of 1990s and identify the increase in annual precipitation compared to the several decades prior to the 1990s. Finally, we explored the changes in precipitation and sea level pressure in the context of large-scale climate anomalies using reanalysis data, for a given change point. It was concluded that the identified large-scale patterns were substantially different from each other.

• Korean Journal of Remote Sensing
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• v.11 no.2
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• pp.17-27
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• 1995

One of the world widely used methods in determining the intensity of a typhoon is Dvorak's technique. By applying the Dvorak's method to the typhoons which affected our country in various degress and extents without regard to their individual severity, we estimated their intensity for six different cases of typhoons. We have derived a regression equation of estimating the central pressures and maximum wind speeds for the six selected typhoons. Their intensity was estimated from the Dvork's method using GMS satellite image data. The derived equation has tested to typhoon ORCHID and the computed values have been compared with the direct observations in its central pressure and maximum wind speed. The computed values in the Dvork's method are smaller in their magnitudes than the observed corresponding values. But their relative magnitudes do not change so much at each different time step. But our results are significantly different from those of NOAA and JMA. The cause of differences are not investigated in depth in this analysis.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.1-12
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• 2019

Earthquake can change underground stress condition around the hypocenter and affect the fracture systems of the rocks. In Korea, the M5.8 Gyeongju earthquake on September 12, 2016 and M5.4 Pohang earthquake on November 15, 2017 occurred inside the Yangsan fault zone and possibly affected the fracture systems in the Yangsan fault zone and nearby rock masses. In this study, the characteristics of the fracture system (fracture orientation, number of the fractures, fracture spacing and aperture, dip angle, fracture density along depth, and relative rock strength) of the rocks in the low/intermediate level radioactive waste repository site located in the coastal area of the East Sea are analyzed by the impact of the Gyeongju and Pohang earthquakes using acoustic televiewer data taken from the boreholes at the radioactive waste repository site in 2005 and 2018. As a result of acoustic televiewer logging analysis, the fracture numbers, fracture aperture, and fracture density along depth overall increased in 2018 comparing to those in 2005. This increase tendency may be due to changes in the fracture system due to the impact of the earthquakes, or due to weathering of the wall of the boreholes for a long period longer than 10 years after the installation of the boreholes in 2005. In the borehole KB-14, on the whole, the orientation of the fractures and the average fracture spacing are slightly different between 2005 and 2018, while dip angle and relative rock strength in 2005 and 2018 are similar each other.

• Journal of The Geomorphological Association of Korea
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• v.18 no.3
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• pp.37-51
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• 2011

Geomorphic changes and sedimentary changes are investigated by sediment analysis from estuarine tidal flat, Mosan Bay Estuary, which is a tide-dominated and rias estuary. Sediments separatedly deposited during the early Holocene and the late Holocene. There are unconformities between the early Holocene sediment unit and the late Holocene sediment unit. Developments of these unconformities were related with fluctuated sea level change during the mid Holocene. Three deposit zones are spatially classified, which are named "intermittent tide channel deposit zone"(A1, B1, D3), "flood-dominated deposit zone"(A3, B3, C1, C3), and "fluvial sediment deposit zone"(A2, B2). This classification is explained by three main effects; laterally restricted migration of a tidal channel, diffract flood effect and settling lag effect, and fluvial induced reworking. These effects are deserved as main factors which have formed estuarine geomorphology in tidedominated and rias estuary. This study suggests research directions in reconstructing estuarine geomorphic and sedimentary change in west coast of Korea. Furthermore, it gives useful data for making a "land-ocean interaction" model for west coast of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.149-155
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• 2017

To establish cultivation areas for the stable production of yacon, this study investigated the productivity and functional component contents of yacon in eight regions of Korea from 2011 to 2013. The results of principal component analysis using these data were as follows. A survey of 16 agricultural traits and meteorological data in the eight yacon cultivation areas showed that five factors (average temperature, maximum temperature, minimum temperature, frost-free days, and fructooligosaccharide content) were highly significant at the p < 0.001 level. Among the 16 agricultural traits and meteorological data used in the main component analysis of yacon cultivation areas, approximately eight contributed to the first principal component, and approximately four contributed to each of the second and third principal components. In particular, factors related to productivity, fructooligosaccharide content, and temperature change were considered important criteria for the classification of cultivation areas. The cultivation areas were divided into three groups by principal component analysis. In Group I, containing the Jinbu and Bonghwa areas in the mid-highland region at 500-560 m above sea level, the product yield was the highest at 2,622-3,196 kg/10a, the fructooligosaccharide content was also the highest at 9.04-9.62%, and the mean temperature was $17.3-18.5^{\circ}C$. In Group II, the areas Suncheon, Okcheon, Yeoju, and Gangneung, at 20-180 m above sea level, had the lowest yield, relatively lower fructooligosaccharide content, and the highest temperature. The areas in Group III showed values intermediate between those of Group I and Group II. For the different yacon cultivation areas, the product quantity and fructooligosaccharide content differed according to the environmental temperature, and the temperature conditions and number of frost-free days are considered important indicators for cultivation sites. Therefore, in terms of producing yacon with high quality, cultivation at 500-560 m is considered to give a higher yield and functional fructooligosaccharide content.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.83-96
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• 2017

A constructed sea stream in Yeongdo, Busan, Republic of Korea is mostly static due to the lifted stream bed and tidal characters, and receives domestic wastewater nearby, causing a consistent odor production and water quality degradation. Bioaugmentation of a microbial consortium was proposed as an effective and economical restoration technology to restore the polluted stream. The microbial consortium activated on site was augmented on a periodic basis (7~10 days) into the most polluted site (Site 2) which was chosen considering the pollution level and tidal movement. Physicochemical parameters of water qualities were monitored including pH, temperature, DO, ORP, SS, COD, T-N, and T-P. COD and microbial community analyses of the sediments were also performed. A significant reduction in SS, COD, T-N, and COD (sediment) at Site 2 occurred showing their removal rates 51%, 58% and 27% and 35%, respectively, in 13 months while T-P increased by 47%. In most of the test sites, population densities of sulfate reducing bacterial (SRB) groups (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc, and Desulfobacter postgatei) and Anaerolinaeles was observed to generally decrease after the bioaugmentation while those of Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, and Flavobacteriales_uc_s appeared to generally increase. Aerobic microbial communities (Flavobacteriaceae_uc_s) were dominant in St. 4 that showed the highest level of DO and least level of COD. These microbial communities could be used as an indicator organism to monitor the restoration process. The alpha diversity indices (OTUs, Chao1, and Shannon) of microbial communities generally decreased after the augmentation. Fast uniFrac analysis of all the samples of different sites and dates showed that there was a similarity in the microbial community structures regardless of samples as the augmentation advanced in comparison with before- and early bioaugmentation event, indicating occurrence of changing of the indigenous microbial community structures. It was concluded that the bioaugmentation could improve the polluted water quality and simultaneously change the microbial community structures via their niche changes. This in situ remediation technology will contribute to an eco-friendly and economically cleaning up of polluted streams of brine water and freshwater.

• Journal of the Korean earth science society
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• v.45 no.3
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• pp.239-259
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• 2024

In this study, a qualitative meta-analysis was conducted on research papers on earth science education to derive knowledge of students' understanding of specific science topics-greenhouse effect, global warming, and climate change-within the context of collective Pedagogical Content Knowledge (PCK). Twenty-two research papers addressing students' alternative conceptions (misconceptions) about these topics were selected and analyzed for their respective definitions, causes (mechanisms), and impacts. Semantic network analysis and a mental model framework were applied to synthesize the findings. The meta-analysis revealed several key insights: (1) Regarding the greenhouse effect, students often used the terms "greenhouse effect" and "global warming" interchangeably, lacked knowledge about the types of greenhouse gases, and misunderstood their roles. They commonly associated the greenhouse effect with environmental pollution or changes in the ozone layer, failing to recognize its relation to the heat balance between the surface and atmosphere. (2) Concerning global warming, students confused it with sea level rise and linked it to pollution, ozone layer changes, and glacier melting. They understood global warming as a disruption of the heat balance between the surface and atmosphere but had misconceptions about its environmental impacts. (3) In terms of climate change, students used the term interchangeably with global warming, weather change, and climate anomalies. They associated climate change with atmospheric pollution and ozone layer depletion but misunderstood its environmental impacts. As result, three mental models-categorical, mechanistic, and hierarchical misconceptions-were identified as collective PCK. The implications for enhancing earth science teachers' PCK were discussed based on these findings.