• Korean Journal of Environment and Ecology
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• 제36권5호
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• pp.445-459
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• 2022

In this study, we investigated current vegetation and assessed the health of vegetation through the KERVI (Korea Estuary Riparian Vegetation Index) to monitor vegetation changes near estuaries due to the opening of the Nakdong River estuary. As the first investigation of the long-term monitoring, six areas near the Nakdong River estuary were surveyed twice in July and October 2021, and vegetation monitoring and a survey of species composition and distribution density of aquatic, riparian, and land plants were carried out. The survey identified 262 taxa, 82 families, 192 genera, 196 species, 3 subspecies, 26 varieties, and 1 form of vascular plants in the surveyed area. The results of the vegetation health assessment through KREVI showed that sites 1 and 6 were rated "Very good" in both surveys, sites 2 and 4 were rated "Very good" in the first survey and then "Good"in the second survey, and site 3 and 5 were rated one grade higher in the second survey than the first survey. The assessment showed that the health grades of most species in the survey area were generally high. Most of the potential natural vegetation after the opening of estuary gates to create a brackish water area is expected to consist of reed (Phragmites communisTrin.) communities. The area of the willow (Salix koreensisAndersson) community adjacent to the water area may be somewhat narrower, but the community will be maintained. In the case of freshwater areas in inland areas with very low salinity, reeds (Phragmites communisTrin.) are expected to occupy most of them, and some communities such as amur silver-grass (Miscanthus sacchariflorusBenth.) and cattails (Typha orientalisC. Presl) are expected to be distributed. We suggest establishing measures such as estuary gate operation to create healthy brackish water regions through long-term monitoring.

• Journal of Korean Society of Disaster and Security
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• 제14권4호
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• pp.69-80
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• 2021

This study tried to suggest improvement measures by discovering problems or matters requiring improvement among the annual regional safety evaluation systems. Briefly introducing the structure and contents of the study, which is the introduction, describes the regional safety evaluation method newly applied by the Ministry of Public Administration and Security in 2020. Utilization plans were also introduced according to the local safety level that was finally evaluated by the local government. In this paper, various views of previous researchers related to regional safety are summarized and described. In addition, problems were drawn in the composition of the index of local safety, the method of calculating the index, and the application of the current index. Next, the problems of specific regional safety evaluation indicators were analyzed and solutions were presented. First, "Number of semi-basement households" is replaced with "Number of households receiving basic livelihood" of 「Social Vulnerability Index」 in the field of disaster risk factors is replaced with "the number of households receiving basic livelihood". In addition, the "Vinyl House Area" is evaluated by replacing "the number of households living in a Vinyl House, the number of container households, and the number of households in Jjok-bang villages" with data. Second, in the management and evaluation of habitual drought disaster areas, local governments with a water supply rate of 95% or higher in Counties, Cities, and Districts are treated as "missing". This is because drought disasters rarely occur in the metropolitan area and local governments that have undergone urbanization. Third, the activities of safety sheriffs, safety monitor volunteers, and disaster safety silver monitoring groups along with the local autonomous prevention foundation are added to the evaluation of the evaluation index of 「Regional Autonomous Prevention Foundation Activation」 in the field of response to disaster prevention measures. However, since the name of the local autonomous disaster prevention organization may be different for each local government, if it is an autonomous disaster prevention organization organized and active for disaster prevention, it would be appropriate to evaluate the results by summing up all of its activities. Fourth, among the Scorecard evaluation items, which is a safe city evaluation tool used by the United Nations Office for Disaster Risk Reduction(UNDRR), the item "preservation of natural buffers to strengthen the protection functions provided by natural ecosystems" is borrowed, which is closely related to natural disasters. The Scorecard evaluation is an assessment index that focuses on improving the disaster resilience of local governments while carrying out the campaign "Creating cities resilient to climate crises and disasters" emphasized by UNDRR. Finally, the names of "regional safety level" and "local safety index" are similar, so the term of local safety level is changed to "natural disaster safety level" or "natural calamity safety level". This is because only the general public can distinguish the local safety level from the local safety index.

• Journal of Environmental Impact Assessment
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• 제31권6호
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• pp.388-408
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• 2022

This study was conducted to select the indicator species (plant) according to the topographical characteristics in the Picea jezoensis forests, endangered subalpine coniferous trees. In South Korea and China (close to Baekdusan), the southern tree line limit of Picea jezoensis has meaningful geographical and latitudinal values for analyzing the ecological characteristics of P. jezoensis forests. Latitude greatly affects the geographical values of plant ecology, and the difference in latitude and habitat affects the change in species composition in forests. With prolonged environmental change, the habitat of subalpine plants will become smaller, and the plants may become extinct. As the P. jezoensis forests of South Korea and China, in particular, are in danger of disappearing without protection, it is important to monitor the population and develop a conservation strategy. Eighty-seven circular plots were established in P. jezoensis forests in South Korea and China. Through processes such as MRPP-test and NMS ordination, indicator species were selected based on this, and basic data for biodiversity assessment were presented. As a result of the Indicator Species Analysis (ISA), 5 taxa were selected from the upperstory vegetation and 18 taxa from the understory vegetation at the altitude(p<0.05). Indicator species by aspect were analyzed as 3 taxa for upperstory vegetation and 16 taxa for understory vegetation (p<0.05). In the case of indicator species according to the slope, 6 taxa for upper vegetation and 24 taxa for understory vegetation were selected(p<0.05). As for the indicator species according to their habitat, 8 taxa in upper vegetation and 65 taxa on understory vegetation were selected. As a result of MRPP-test, it was analyzed that the species composition was heterogeneous in the group of understory vegetation than that of upperstory vegetation. As a result of NMS ordination, the correlation with environmental factors of indicator species was analyzed by rock exposure for upperstory vegetation and latitude for understory vegetation (cut off level=0.3).

• Journal of the Korea Institute of Building Construction
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• 제22권6호
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• pp.651-662
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• 2022

The electrochemical impedance spectroscopy(EIS) method was used to evaluate the concrete deterioration process related to chloride-induced steel corrosion with various corrosion levels(initiation, rust propagation and acceleration periods). The impressed current technique, with four total current levels of 0C, 13C, 65C and 130C, was used to accelerate steel corrosion in concrete cylinder samples with w/c ratio of 0.4, 0.5, and 0.6, immersed in a 0.5M NaCl solution. A series of EIS measurements was performed to monitor concrete deterioration during the accelerated corrosion test in this study. Some critical parameters of the equivalent circuit were obtained through the EIS analysis. It was observed that the charge transfer resistance(R_c) dropped sharply as the impressed current increased from 0C to 13C, indicating a value of approximately 10kΩcm². However, the sensitivity of R_c significantly decreased when the impressed current was further increased from 13C to 130C after corrosion of steel had been initiated. Meanwhile, the double-layer capacitance value(C_dl) linearly increased from 50×10^-6μF/cm² to 250×10^-6μF/cm² as the impressed current in creased from 0C to 130C. The results in this study showed that monitoring C_dl is an effective measurement parameter for evaluating the progress of internal concrete damages(de-bonding between steel and concrete, micro-cracks, and surface-breaking cracks) induced by steel corrosion. The findings of this study provide a fundamental basis for developing an embedded sensor and signal interpretation method for monitoring concrete deterioration due to steel corrosion at various corrosion levels.

• Economic and Environmental Geology
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• 제55권4호
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• pp.407-419
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• 2022

Soil(vadose zone) gas compositions were measured for about 3 days to suggest a method for monitoring and interpreting soil gas data collected around wells from which methane(CH₄) is outflowing. The vadose zone gas samples were collected within 1 m around two test wells(TB2 and TB3) at Pohang and analyzed for CO₂, CH₄, N₂ and O₂ concentrations in situ. CO₂ flux was measured beside TB2. In addition, gas samples from well head in TB2 and atmospheric air samples were collected for comparison. Carbon isotopes of CO₂(δ¹³C_CO2) of samples collected on the last day of the study period were analyzed in the laboratory. The two test wells (TB2 and 3) were 12.7 m apart and only TB3 was cemented to the surface. According to the bio-geochemical process-based interpretation, the relationships between CO₂ and O₂, N₂, and N₂/O₂ of vadose zone gas were plotted between the lines of CH₄ oxidation and CO₂ dissolution. In addition, the CH₄ concentrations of gas samples from the wellhead of the uncemented well (TB2) were 5.2 times higher than the atmospheric CH₄ concentration. High CO₂ concentrations (average 1.148%) of vadose zone gas around TB2 seemed to be attributed to the oxidation of CH₄. On the other hand, the vadose zone CO₂ around the cemented well(TB3) showed a relatively low concentration(0.136%). This difference indicates that the vadose zone gas(including CO₂) around the CH₄ outflowing well were strongly affected by well completion(cementing). This study result can be used to establish strategies for environmental monitoring of soil around natural gas sites, and can be used to monitor leakage around injection and observation wells for CO₂ geological storage. In addition, the method of this study is useful for soil monitoring in natural gas storage and oil-contaminated sites.

• Tunnel and Underground Space
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• 제32권5호
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• pp.285-297
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• 2022

We report results of Extended Leak-Off Test (XLOT) conducted in a large diameter borehole, which is drilled for installation of deep borehole geophysical monitoring system to monitor micro-earthquakes and fault behavior of major fault zones in the southeastern Korean Peninsula. The borehole was planned to secure a final diameter of 200 mm (or more) at a depth of ~1 km, with 12" diameter wellbore to intermediate depths, and 7-7/8" (~200 mm) to the bottom hole depth. We drilled first the 12" borehole to approximately 504 m deep and installed American Petroleum Institute standard 8-5/8" casing, then annulus between the casing and bedrock was fully cemented. XLOT was carried out for several purposes such as confirming casing and cementing integrity, measuring rock stress states. To that end, we drilled additional 4 m long open hole interval to directly inject water and pressurize into the rock mass using the upper API casings. During the XLOT, flow rates and interval pressures were recorded in real time. Based on the logs we tried to analyze hydraulic conductivity of the test interval.

• Journal of the Korean Institute of Landscape Architecture
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• 제50권5호
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• pp.30-39
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• 2022

This study aimed to evaluate the awareness of conservation areas and green resources and analyze their characteristics by utilizing accumulated blog data created for specific places and objects. Among all the conservation areas and resources located in the Seoul metropolitan area, places that can be evaluated were classified, and sites were evaluated by dividing them into ten categories based on the number of blog posts written. As a result of the study, the users' awareness of forests was the highest, and the awareness of conservation areas and green resources was higher in urban areas than suburban areas. The result shows that the conservation areas and green resources located around the metropolitan area serve as natural tourist destinations while being the object of conservation for users. In addition, these results are in the same vein as the research results in domestic and foreign studies on the importance of ecosystem services in urban areas. Unlike existing research methods, this study is meaningful in that it identified the level of user awareness through social media analysis and applied it to evaluating conservation areas and green resources. It can be used as basic data to prepare a management plan considering public interest and awareness or to establish a development plan to increase awareness. In addition, the cumulative amount of blog content used in the study is meaningful in that it can identify and monitor users' interest in the space. However, it was not possible to examine the contents of each blog in detail because it was evaluated based on the amount of social media content. In addition, in the case of conservation areas and green resources, it is necessary to review and supplement the evaluation contents by adding keyword analysis and content analysis for the site to be evaluated as content other than the pure viewpoint of users may be mixed with development issues.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제40권5호
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• pp.580-586
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• 1995

Soil temperatures at depths of 1~5cm are important to the germination and emergence of dry seeded-rice. An automated weather station was used to monitor the hourly weather parameters at Experiment Farm, Kyung Hee University from April 21 to May 30 in 1994. The data was analyzed to figure out the 24-hour temporal changes in air 1.5m above ground and soil temperatures under ground of 0, 2.5, 5, 10 and 20cm. The fluctuations of soil temperature were greatest at the soil surface and decreased with increasing depth. Mean soil temperatures at depth of 2.5cm were about 3$^{\circ}C$ higher than mean air temperatures during the observation period. Although mean soil temperatures at depth of 2.5cm during 10 or 15 days after April 21, May 1 and May 11 showed almost same temperatures, the distribution patterns of temperature regime were different from each other. Rice cultivars, Hwasung, Seohae, Nampung, IR60 and CR155, were seeded at depth of 2.5cm on April 21, May 1 and May 11, respectively. The periods of seedling emergence(PSE) varied in accordance with cultivars and seeding dates. PSE was correlated with accumulated daily mean air temperatures and accumulated hours classified by temperature regimes.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• 제41권2호
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• pp.11-18
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• 2023

This study aims to distinguish what can be used in consideration of the national situation with Korea for Chinese Scenic and Historic Interest Areas, and the results are as follows; First, the Chinese Scenic and Historic Interest Areas expanded to the existing scenic cruise culture, travel, and tourism culture in the process of the influx of Western culture in the modern and contemporary era, and became popular as a travel destination. Accordingly, the Chinese government developed the tourism industry around the scenic sites, and thanks to the development of transportation and communication, the Scenic and Historic Interest Areas has become an important national heritage. This influenced the establishment of the system related to Scenic and Historic Interest Areas, and today, it is operated around the Scenic and Historic Interest Areas ordinance. Second, the designation of the Scenic and Historic Interest Areas is divided into the size of the site according to the area, and the process of selecting the Scenic and Historic Interest Areas classification, rating evaluation, and comprehensive value evaluation according to evaluation indicators and rating standards is carried out. Accordingly, according to the results of the classification, it is subdivided from the national level to the Scenic and Historic Interest Areas at the local level. Third, the central government is in charge of managing and supervising Scenic and Historic Interest Areas across the country, and the local government's construction department is in charge of supervising Scenic and Historic Interest Areas in the region. The management organization of Scenic and Historic Interest Areas established by local governments above the county level has a system that actually protects, utilizes, and manages Scenic and Historic Interest Areas. In addition, 14 detailed indicators are used to monitor Scenic and Historic Interest Areas. Based on these results, considering the application of the domestic scenic site policy, the method of developing the policy that has established the system from the perspective of the utilization of the people is worth considering. On the other hand, the evaluation of the designation and management system through the setting of various indicators has limitations in that it is difficult to secure objectivity in impressing or evaluating the landscape. Therefore, rather than blindly introducing quantified evaluation, it seems that guidance and promotion on how to expand consensus on scenic values and enjoy heritage should be prioritized.

• Research in Plant Disease
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• 제28권4호
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• pp.221-230
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• 2022

The fire blight caused by Erwinia amylovora (Ea) was first reported in 2015 in Korea, and the disease has rapidly spread to 22 regions until 2021. In Korea, all host plants in the apple and pear orchards where fire blight occurred should be eliminated and buried by the Plant Protection Act. To prevent the spread of the disease, all burial sites were prohibited from planting the new host plants for the next three years. To confirm the eradication efficiency of Ea and the reoccurrence of fire blight, the surveillance facilities were established on three burial sites from 2019 to 2020 in Anseong-si, Gyeonggi-do, and Chungju-si, Chungcheongbuk-do. As host plants, five apple trees of fire blight-susceptible cultivar 'Fuji', were planted in each facility. All facilities were enclosed with fences and nets and equipped with two CCTVs, motion sensors, and several other sensors for recording weather conditions to monitor the environment of the sentinel plants in real-time. The sentinel plants were checked for the reoccurrence of fire blight routinely. Suspicious plant parts were collected and analyzed for Ea detection by loop-mediated isothermal amplification polymerase chain reaction and conventional polymerase chain reaction. Until November 2022, Ea has not been detected in all sentinel plants. These results might support that the burial control of infected plants in soil works efficiently to remove Ea and support the possibility to shorten the prohibition period of host plant establishment in the burial sites.