• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.1-13
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• 2009

Liquefaction is a significant threat to structures on loose saturated sandy soil deposits in the event of an earthquake, and can often cause catastrophic damage, economic loss, and loss of life. Nevertheless, the Korean peninsula has for a long time been recognized as a safe region with respect to the hazard of liquefaction, as the peninsula is located in a moderate seismicity region, and there have been no reports of liquefaction, with the exception of references in some historical documents. However, some earthquakes that have recently occurred in different parts of the world have led to liquefaction in non-plastic silty soils, a soil type that can be found in many of the western coastal areas of Korea. In this study, we first present procedures for evaluating the liquefaction potential, and calculate the liquefaction potential index (LPI) distribution at two western coastal sites using both piezocone penetration test (CPTu) data and standard penetration test (SPT) data. The LPI is computed by integrating liquefaction potential over a depth of 20m, and provides an estimate of liquefaction-related surface damage. In addition, we compared the LPI values obtained from CPTu and SPT, respectively. Our research found that the CRR values from CPTu were lower than those from the SPT, particularly in the range between 40 and 120 for the corrected tip resistance, (qc1N)CS, from the CPTu, or in the range of CRR less than 0.23, resulting in relatively high LPI values. Moreover, it was observed that the differences in the CRR between the two methods were relatively higher for soils with high fine contents.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.359-366
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• 2021

This study aimed to develop and verify the smart human resource management (HRM) program in a large scale greenhouse. HRM program delivers detailed work orders to workers and gathers work results by mobile phone application. Greenhouse managers can monitor the workload, work speed, quality of employee by HRM program and can analyse performance easily. Greenhouse Managers can set the work speed including 'twisting', 'trimming' and 'harvesting' in a greenhouse. It makes planning work schedule and assigns resources to each specific job easier. Therefore, the manager can arrange the number of employees to promote work performance and also easy to estimate the labor shortage. Greenhouse managers can evaluate the adequacy of the number of employees through job performance analysis by period and adjusts the supply/demand ratio of regular and non-regular employees. The HRM program can improve work efficiency by announcing the real-time work performance of all employees on a monitor screen to induce competition among workers and re-educate unripe employees who accomplish behind average to improving work skills.

• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.1-8
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• 2018

Extreme climate phenomena are occurring around the world caused by global climate change. The heavy rains exceeds the previous record of highest rainfall. In particular, as flash floods generate heavy rainfall on the mountains over a relatively a short period of time, the likelihood of landslides increases. Gangwon region is especially suffered by landslide damages, because the most of the part is mountainous, steep, and having shallow soil. Therefore, in this study, is to predict the risk of disasters by applying topographic classification techniques and landslide risk prediction techniques to mountain watersheds. Classify the hazardous area by calculating the topographic position index (TPI) as a topographic classification technique. The SINMAP method, one of the earth rock predictors, was used to predict possible areas of a landslide. Using the SINMAP method, we predicted the area where the mountainous disaster can occur. As a result, the topographic classification technique classified more than 63% of the total watershed into open slope and upper slope. In the SINMAP analysis, about 58% of the total watershed was analyzed as a hazard area. Due to recent developments, measures to reduce mountain disasters are urgently needed. Stability measures should be established for hazard zone.

• Phonetics and Speech Sciences
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• v.15 no.2
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• pp.31-40
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• 2023

Tube phonation in water has been widely used for voice training among semi-occluded vocal tract (SOVT) exercises in which the patient bubbles with phonation keeping the tube submerged in water. This study aims to investigate the effect of tube diameter and water depth on bubble height and maximum phonation time (MPT) for patients with hyperfunctional voice disorders. Seventeen patients with hyperfunctional voice disorders were asked to bubble with sustained /u/ at the different inner diameters of tube (5, 7, and 10 mm), water depth (4, 7, and 10 cm). A water resistance phonation biofeedback system using a water height sensor was used for recording bubble height and MPT. The bubble height was significantly changed by the tube diameter while MPT was significantly changed with the tube diameter and water depth. Although the wider tube presented significantly lower bubble height for a given depth, relatively consistent bubble height was maintained. Depending on the water depth, the bubble height did not significantly differ for a given tube diameter. In addtion, MPT significantly decreased with water depth and a wider tube led significantly shorter MPT. A water level-driven water resistance biofeedback system provided useful information on bubble characteristics and vocal fold vibration depending on tube diameter and water depth. It can be useful to monitor the breath support during water resistance phonation for patients with hyperfunctional voice disorders.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.152-161
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• 2023

In general, large-capacity hydrogen storage vessels, typically in the form of vertical cylindrical vessels, are constructed using steel materials. These vessels are anchored to foundation slabs that are specially designed to suit the environmental conditions. This anchoring method involves pre-installed anchors on top of the concrete foundation slab. However, it's important to note that such a design can result in concentrated stresses at the anchoring points when external forces, such as seismic events, are at play. This may lead to potential structural damage due to anchor and concrete damage. For this reason, in this study, it selected an vertical hydrogen storage vessel based on site observations and created a 3D finite element model. Artificial seismic motions made following the procedures specified in ICC-ES AC 156, as well as domestic recorded earthquakes with a magnitude greater than 5.0, were applied to analyze the structural behavior and performance of the target structures. Conducting experiments on a structure built to actual scale would be ideal, but due to practical constraints, it proved challenging to execute. Therefore, it opted for an analytical approach to assess the safety of the target structure. Regarding the structural response characteristics, the acceleration induced by seismic motion was observed to amplify by approximately ten times compared to the input seismic motions. Additionally, there was a tendency for a decrease in amplification as the response acceleration was transmitted to the point where the centre of gravity is located. For the vulnerable components, specifically the sub-system (support columns and anchorages), the stress levels were found to satisfy the allowable stress criteria. However, the concrete's tensile strength exhibited only about a 5% margin of safety compared to the allowable stress. This indicates the need for mitigation strategies in addressing these concerns. Based on the research findings presented in this paper, it is anticipated that predictable load information for the design of storage vessels required for future shaking table tests will be provided.

• Korean Journal of Environment and Ecology
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• v.38 no.3
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• pp.230-245
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• 2024

Amphibians, sensitive to external environmental changes, serve as bioindicator species for assessing alterations or disturbances in local ecosystems. It is known that one-third of amphibian species within the order Anura are at risk of extinction due to anthropogenic threats such as habitat destruction and fragmentation caused by urbanization. To develop effective protection and conservation strategies for anuran amphibians, species surveys that account for population characteristics are essential. This study aimed to investigate the potential for citizen participation in ecological monitoring using the mating calls of anura species. We also proposed suitable quality control measures to mitigate errors and biases, ensuring the extraction of reliable species occurrence data. The Citizen Science project was carried out nationwide from April 1 to August 31, 2022, targeting 12 species of anura amphibians in Korea. Citizens voluntarily participated in voice signal monitoring, where they listened to anura species' mating calls and recorded them using a mobile application. Additionally, we established a quality control process to extract reliable species occurrence data, categorizing errors and biases from citizen-collected data into three levels: omission, commission, and incorrect identification. A total of 6,808 observations were collected during the citizen participation in anura species vocalization monitoring. Through the quality control process, errors and biases were identified in 1,944 (28.55%) of the 6,808 data. The most common type of error was omission, accounting for 922 cases (47.43%), followed by incorrect identification with 540 cases (27.78%), and commission with 482 cases (24.79%). During the Citizen Science project, we successfully recorded the mating calls of 10 out of the 12 anuran amphibian species in Korea, excluding the Asian toads (Bufo gargarizans Cantor), Korean brown frog (Rana coreana). Difficulties in collecting mating calls were primarily attributed to challenges in observing due to population decline or discrepancies between the breeding season of non-emergent individuals and the timing of the citizen science project. This study represents the first investigation of distribution status and species emergence data collection through mating calls of anura species in Korea based on citizen participation. It can serve as a foundation for designing future bioacoustic monitoring that incorporates citizen science and quality control measures for citizen science data.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.1-13
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• 2018

Both Platform as a Service (PaaS) as one of the cloud computing service models and the e-government (e-Gov) standard framework from the Ministry of the Interior and Safety (MOIS) provide developers with practical computing environments to build their applications in every web-based services. Web application developers in the geo-spatial information field can utilize and deploy many middleware software or common functions provided by either the cloud-based service or the e-Gov standard framework. However, there are few studies for their applicability and performance in the field of actual geo-spatial information application yet. Therefore, the motivation of this study was to investigate the relevance of these technologies or platform. The applicability of these computing environments and the performance evaluation were performed after a test application deployment of the spatial image processing case service using Web Processing Service (WPS) 2.0 on the e-Gov standard framework. This system was a test service supported by a cloud environment of Cloud Foundry, one of open source PaaS cloud platforms. Using these components, the performance of the test system in two cases of 300 and 500 threads was assessed through a comparison test with two kinds of service: a service case for only the PaaS and that on the e-Gov on the PaaS. The performance measurements were based on the recording of response time with respect to users' requests during 3,600 seconds. According to the experimental results, all the test cases of the e-Gov on PaaS considered showed a greater performance. It is expected that the e-Gov standard framework on the PaaS cloud would be important factors to build the web-based spatial information service, especially in public sectors.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.4
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• pp.58-69
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• 2018

The purpose of this study was to present specific standards for landscape planning and construction applicable to landscaping areas in various historical sites. The results are as follows: First, the types of historical sites are classified according to their preservation status and processing techniques, and the classification according to their status is divided into those that have been buried underground, such as those that have been exposed to the ground, such as buildings and structures, and those that have a reputation or a record of the sites. The classification according to the wartime processing technique was classified by such techniques as closures that isolate the site, penetration that can be seen on the site, and overlays where a separate protection facility is installed on the site. Second, the principles of landscape planning for display of historical sites are divided into the items that make up the historical site, surface treatment of the sites, tree planting, and installation of facilities. If the site is not a circular space, the area separating the space by different materials between the components is required. In the event that preservation of the historical site is required, it is deemed desirable to use the soil, and to do so, the use of grasses and shrubs is effectively considered to be effective. The introduction of plants and plants should be considered according to the nature of the space. Depending on the area and nature of the monument, the facility is required to take a cautious approach by reviewing its influence on the landscape and the additional excavation of the monument. Third, the readjustment method derived as a result of looking at the landscaping principle in the historical site space was classified as conservation of status, installation of protection facilities, burial, restoration, relocation, and reproduction. Preservation of the status quo is essential for limited landscape planning and should not affect the prototype of existing relics. The protection facility shall be installed where necessary to protect the relics, and when the soil is formed, the surface treatment shall be required to remove trees that could damage the site and prevent soil and soil oil from being lost after the site. The restoration shall establish a landscaping plan according to the circular preservation based on the clues to the circle. The transfer requires a landscaping plan to create an environment similar to the outer space of an existing site and should be able to highlight the value or location of the original site. The reenactment should have a landscaping plan to revive the landscape and atmosphere of the past for the now-defunct remains. Fourth, landscaping can simultaneously satisfy the preservation of excavation sites and the increase in exhibition effects. In order to protect the traces of the past and vitalize the site of the ruins today, specific measures are required, the creation of a park for historical sites that preserve the functions and value of the relics, and the formation of a shape of linked contents can be suggested as alternatives.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.433-441
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• 2022

Light pollution is one of the factors that disturb coastal and island ecosystems. This study examined the factors causing light pollution in the islands in Daedohaehaesang National Park using nighttime satellite images. This study selected 101 islands with an area of 100,000 m² or more in Daedohaehaesang National Park, and measured the levels of light pollution of the selected islands by calculating mean nighttime radiance recorded in VIIRS DNB monthly images for January, April, August, and October 2019. Of seven districts of the park, The highest mean nighttime radiance was recorded in Geumodo district (17,666nW/m²/sr), followed by Geonumdo·Baekdo, Narodo, Soando·Cheongsando districts. By season, mean nighttime radiance in October was the highest at 9,509nW/m²/sr, followed by August, January, and April. Regression analyses show that the total floor area and the number of lighthouses in a 5 km buffer area had a statistically significant effect on mean nighttime radiance at all times, but those within the island did not, indicating that light pollution in islands in a national park where land development is strictly restricted is influenced by artificial lights in nearby areas. However, the total floor area of an island significantly affected mean nighttime radiance only in August, which appears to be attributed to the impact of intensive use of artificial light by visitors during summer vacation. The size of an island had a negative (-) effect on nighttime radiance. This negative effect suggests that light pollution is a type of ecological edge effect, i.e., the smaller island is more likely to have a relatively larger proportion of edge area that is affected by light emitted from the neighboring areas. The results of this study indicate that managing artificial lights in nearby areas is necessary to mitigate light pollution in islands in marine and coastal national parks.

• Journal of Korea Water Resources Association
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• v.54 no.10
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• pp.795-805
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• 2021

In this study, after developing an LSTM-based deep learning model for estimating daily runoff in the Soyang River Dam basin, the accuracy of the model for various combinations of model structure and input data was investigated. A model was built based on the database consisting of average daily precipitation, average daily temperature, average daily wind speed (input up to here), and daily average flow rate (output) during the first 12 years (1997.1.1-2008.12.31). The Nash-Sutcliffe Model Efficiency Coefficient (NSE) and RMSE were examined for validation using the flow discharge data of the later 12 years (2009.1.1-2020.12.31). The combination that showed the highest accuracy was the case in which all possible input data (12 years of daily precipitation, weather temperature, wind speed) were used on the LSTM model structure with 64 hidden units. The NSE and RMSE of the verification period were 0.862 and 76.8 m³/s, respectively. When the number of hidden units of LSTM exceeds 500, the performance degradation of the model due to overfitting begins to appear, and when the number of hidden units exceeds 1000, the overfitting problem becomes prominent. A model with very high performance (NSE=0.8~0.84) could be obtained when only 12 years of daily precipitation was used for model training. A model with reasonably high performance (NSE=0.63-0.85) when only one year of input data was used for model training. In particular, an accurate model (NSE=0.85) could be obtained if the one year of training data contains a wide magnitude of flow events such as extreme flow and droughts as well as normal events. If the training data includes both the normal and extreme flow rates, input data that is longer than 5 years did not significantly improve the model performance.