• Atmosphere
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• v.31 no.2
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• pp.241-249
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• 2021

A smart city utilizes data collected from various sensors through the internet of things (IoT) and improves city operations across the urban area. Recently substantial research is underway to examine all aspects of data that requires for the smart city operation. Atmospheric data are an essential component for successful smart city implementation, including Urban Air Mobility (UAM), infrastructure planning, safety and convenience, and traffic management. Unfortunately, the current level of conventional atmospheric data does not meet the needs of the new city concept. New and innovative approaches to developing high spatiotemporal resolution of observational and modeling data, resolving the complex urban structure, are expected to support the future needs. The geographic information system (GIS) integrates the atmospheric data with the urban structure and offers information system enhancement. In this study we proposed the necessity and applicability of the high resolution urban meteorological dataset based on heavy fog cases in the smart city region (e.g., Sejong and Pusan) in Korea.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.365-379
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• 2021

Hydrological model parameters are essential for model simulation and can vary over time due to topography, climatic conditions, climate change and human activity. Consequently, the use of fixed parameters can lead to inaccurate stream flow simulations. The aim of this study is to investigate an appropriate method of estimating time-varying parameters using stream flow observations, and how the simulation efficiency changes when stream flow data are assimilated into the model. The data assimilation method can be used to automatically estimate the parameters of a hydrological model by adapting to a variety of changing environments. Stream flow observations were assimilated into a two parameter monthly water balance model using a particle filter. The simulation results using the time-varying parameters by the data assimilation method were compared with the simulation results using the fixed parameters by the SCEM method. First, we conducted synthesis experiments based on various scenarios to investigate if the particle filter method can adequately track parameters that change over time. After that, it was applied to actual watersheds and compared with the predictive performance of stream flow when using parameters that change with time and fixed parameters. The conclusions obtained through this study are as follows: (1) The predictive performance of the overall monthly stream flow time series was similar between the particle filter method and the SCEM method. (2) The monthly runoff prediction performance in the period except the rainy season was better in the simulation by the periodically changing parameters using the data assimilation method. (3) Uncertainty in the observational data of stream flow used for assimilation played an important role in the predictive performance of the particle filter.

• 한국사회정책
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• v.23 no.2
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• pp.83-112
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• 2016

Increase of immigrants in Korean society means that ethnic and cultural diversity witnessed in Western immigration countries is also appearing in overall Korean society. The purpose of this study is to suggest policy directions which fit multicultural society in the future by comparing and analyzing the difference in the recognition of multiculturalism between Koreans and immigrants. As the result of empirical analysis, it turned out that there is difference in recognition between Koreans and immigrants, for which different policy directions are required. First, it was contact experience that decided Koreans' multicultural attitudes. High level of influence of contact experience means that although Koreans take multicultural society as granted, they actually have low level of contact experience with immigrants, which requires policy tools to convert actual strengthened contact experience into positive directions. Second, in the case of immigrants, the less they recognize discrimination and the more bias is fortified, the more they accept multiculturalism as a threat. This exhibits their dual sense of identity in which they recognize themselves as foreigners toward Koreans but they distinguish themselves from other foreigners. Thus, assimilation to Korean society is not deemed to be the only alternative and Korean society needs to practice genuine multiculturalism to strengthen immigrants' ethnic identity. Study also conducted in-depth discussions on the implications of above results.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.2
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• pp.122-133
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• 2021

Cultivar parameter calibration can be affected by the reliability of the input data to a crop growth model. In South Korea, two sets of weather stations, which are included in the automated synoptic observing system (ASOS) or the automatic weather system (AWS), are available for preparation of the weather input data. The objectives of this study were to estimate the cultivar parameter using those sets of weather data and to compare the uncertainty of these parameters. The cultivar parameters of CERES-Rice model for Shindongjin cultivar was calibrated using the weather data measured at the weather stations included in either ASO S or AWS. The observation data of crop growth and management at the experiment farms were retrieved from the report of new cultivar development and research published by Rural Development Administration. The weather stations were chosen to be the nearest neighbor to the experiment farms where crop data were collected. The Generalized Likelihood Uncertainty Estimation (GLUE) method was used to calibrate the cultivar parameters for 100 times, which resulted in the distribution of parameter values. O n average, the errors of the heading date decreased by one day when the weather input data were obtained from the weather stations included in AWS compared with ASO S. In particular, reduction of the estimation error was observed even when the distance between the experiment farm and the ASOS stations was about 15 km. These results suggest that the use of the AWS stations would improve the reliability and applicability of the crop growth models for decision support as well as parameter calibration.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.1
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• pp.47-61
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• 2022

In this study, We developed VR (Virtual Reality) geological resources based on the Geo Big Data of the Big Data platform that provided by the Korea Institute of Geoscience and Mineral Material (KIGAM). So students selected the theme of lessons by using these resources and we operated Remote classes using the materials that developed as to Virtual Reality. Therefore, the geological theme maps provided by the Geo Big Data Open Platform were reconstructed and produced materials were created for Study about Real Korean geological outcrops grounded in Virtual Reality. And Topographic information data was used to produce class materials for Remote classes. Twenty students were selected by Random sampling, and data were collected by conducting a survey including interviews to confirm the change in students' perception of remote classes in virtual reality geological data development and the effect of the classes, so data were analyzed through inductive categorization. The results of this study are as follows. First, students showed positive responses in terms of interest, utilization, and knowledge utilization as taking remote classes for developing geological data in virtual reality geological data. This is the result of showing the adaptability of diverse and flexible learning getting away from a fixed framework by motivating and encouraging students and inducing cooperation for communication. Second, students recognized distance education in the development of Virtual Reality geological data as 'Realistic hands-on learning process', 'Immersive learning process by motivation', and 'Learning process of acquiring knowledge in the field of earth science'.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.3
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• pp.227-237
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• 2022

The most critical factors for detecting changes in very high-resolution satellite images are building positional inconsistencies and relief displacements caused by satellite side-view. To resolve the above problems, additional processing using a digital elevation model and deep learning approach have been proposed. Unfortunately, these approaches are not sufficiently effective in solving these problems. This study proposed a change detection method that considers both positional and topology information of buildings. Mask R-CNN (Region-based Convolutional Neural Network) was trained on a SpaceNet building detection v2 dataset, and the central points of each building were extracted as building nodes. Then, triangulated irregular network graphs were created on building nodes from temporal images. To extract the area, where there is a structural difference between two graphs, a change index reflecting the similarity of the graphs and differences in the location of building nodes was proposed. Finally, newly changed or deleted buildings were detected by comparing the two graphs. Three pairs of test sites were selected to evaluate the proposed method's effectiveness, and the results showed that changed buildings were detected in the case of side-view satellite images with building positional inconsistencies.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.823-833
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• 2022

This study aims to improve the runoff modeling accuracy of a basin using Hydrological Simulation Program-FORTRAN (HSPF) model by considering nonhomogeneous characteristics of a basin. By entering classified values according to the various types of land cover and soil to the parameters in HSPF-roughness coefficient (NSUR), infiltration (INFILT), and evapotranspiration (LZETP)- the heterogeneity of the Yongdam Dam basin was reflected in the model. The results were analyzed and compared with the one where the parameters were set as a single value throughout the basin. The flow rate and water quality simulation results showed improved results when classified parameters were used by land cover and soil type than when single values were used. The parameterization changed not only the flow rate, but also the composition ratio of each hydrologic components such as surface runoff, baseflow, and evapotranspiration, which shows the impact of the value set to a parameter on the entire hydrological process. This implies the importance of considering the heterogeneous characteristics of the land cover and soil of the basin when setting the parameters in a model.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.117-130
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• 2021

The government's social distancing policy and concerns about COVID-19 are increasing restrictions on outdoor leisure activities. Based on the decrease in outdoor leisure activities and the increase in indoor leisure activities, The purpose of this study is to examine the correlation between the degree of new confirmed cases of COVID-19 and the number of VOD views. This study conducted a time series analysis for 348 days from February 18, 2020 to January 31, 2021. Data were collected from the number of daily VOD views provided by the Korean Film Council and the number of new confirmed cases of COVID-19 provided by the Korea Centers for Disease Control and Prevention. The analysis showed that the number of confirmed COVID-19 cases has a significantly positive effect on the number of daily movie VOD views at the 5% significance level. This results indicate that the more confirmed cases of COVID-10, the more people watch movie VOD as indoor leisure activities. While previous studies examined the relationship between the confirmed cases of COVID-19 and indoor leisure activities in general, this study tried to academically contribute by analyzing the impact on specific indoor leisure activities. The practical implications of this study are as follows. The results of this study show that efficient promotions are possible based on significant social issues, such as infectious diseases. According to the results, promotions that respond quickly to changes are more effective than long-term promotions considering the climate or seasons. Due to the limitations of the data, the current study was conducted based only on PPV, but future research should also consider various billing forms such as PPM and SVOD.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.189-196
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• 2023

As the manufacturing paradigm shifts, various collaborative robots are creating new markets. Demand for collaborative robots is increasing in all industries for the purpose of easy operation, productivity improvement, and replacement of manpower who do simple tasks compared to existing industrial robots. However, accidents frequently occur during work caused by collaborative robots in industrial sites, threatening the safety of workers. In order to construct an industrial site through robots in a human-centered environment, the safety of workers must be guaranteed, and there is a need to develop a collaborative robot guard system that provides reliable communication without the possibility of dispatch. It is necessary to double prevent accidents that occur within the working radius of cobots and reduce the risk of safety accidents through sensors and computer vision. We build a system based on OPC UA, an international protocol for communication with various industrial equipment, and propose a collaborative robot guard system through image analysis using ultrasonic sensors and CNN (Convolution Neural Network). The proposed system evaluates the possibility of robot control in an unsafe situation for a worker.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.171-179
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• 2022

In this study, the characteristics of algae mitigation according to dam operation were quantitatively analyzed for Uiam Lake, where the Chuncheon Dam is located upstream of the main stream, Uiam Dam is located downstream, and Soyang Dam is located in the tributary stream. Nine dam operation scenarios were applied to the event of the summer of 2018 (at that time an algae alert occurred) using the EFDC model, which is capable of calculating three-dimensional hydrodynamics and water quality levels such as those associated with chlorophyll-a. The dam operation scenarios were set to generate a flushing effect via discharges in the form of pulse waves from the upstream dams and by lowering the water level at the downstream dam. At Uiam Lake, the flushing effect was different depending on the operation of the dam, and the amount of algae reduction at each point was different owing to topographic characteristics and the different base water temperatures from BukHan River and Soyang River. With regard to a point located on the left bank, it was predicted that the peak level of chlorophyll-a would be reduced by approximately 50 % or more upon pulsed discharge at 50 m³/s for three days at Soyang Dam. However, for the right bank, the amount of discharge from Soyang Dam had little effect on algae mitigation. Therefore, an appropriate dam operation could be effective for algae mitigation at specific points in the water body where large dams exist upstream and downstream, such as at Uiam Lake, in an emergency situation in which algal blooms rapidly.