• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.42-54
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• 2019

Crop models depend on a large number of input parameters including the cultivar parameters that represent the genetic characteristics of a given cultivar. The cultivar parameters have been estimated using high quality data for crop growth, which require considerable costs and efforts. The objective of this study was to examine the feasibility of using low quality data for the parameter estimation. In the present study, the cultivar parameters for cv. Shindongjin were estimated using the data obtained from the report of new cultivars development and research from 2005 to 2016. The root mean square errors (RMSE) of the heading dates were less than 3 days when the parameters associated with phenology were estimated. In contrast, the coefficient of determination for yield tended to be less than 0.1. The large errors incurred by the fact that no growth data collected over a season was used for parameter estimation. This suggests that detailed observation data needs to be prepared for parameter calibration, which would be aided by remote sensing approaches. The occurrence of natural disasters during a growing season has to be considered because crop models cannot take into account the effects of those events. Still, our results provide a reasonable range for the parameters, which could be used to set the boundary of a given parameter for cultivars similar to cv. Shindongjin in further studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.380-386
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• 2019

Shoulder joint pain is a very common musculoskeletal disorder, in which about 20 percent of adults experience it more than once in their lives. In this study, an objective assessment was made that subacromial space was increased by pectoralis minor stretching exercise, which has a positive effect on impingement syndrome and shoulder pain. Also, This study examined the effects on pectoralis minor length(PML) and acromio-humeral distance(AHD) following pectoralis minor self-stretching exercise in normal adults. In this study, a total of 30 subjects were recruited and randomly divided into a self-stretching exercise group(n=15) and manual stretching exercise group(n=15) to compare the immediate effects of treatment. Studies have shown that both groups have significantly increased both PML and AHD within the group(p<.05). There was no statistically significant difference in the comparison between the groups(p>.05). The results suggest that self-stretching exercise can be recommended as a treatment method for impingement syndrome and prevention of shoulder disease.

• Tunnel and Underground Space
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• v.31 no.5
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• pp.333-359
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• 2021

Gases such as hydrogen and radon can be generated around the canister in high-level radioactive waste disposal systems due to several reasons including the corrosion of metal materials. When the gas generation rate exceeds the gas diffusion rate in the low-permeability bentonite buffer, the gas phase will form and accumulate in the engineered barrier system. If the gas pressure exceeds the gas entry pressure, gas can migrate into the bentonite buffer, resulting in pathway dilation flow and advective flow. Because a sudden occurrence of dilation flow can cause radionuclide leakage out of the engineered barrier of the radioactive waste disposal system, it is necessary to understand the gas migration behavior in the bentonite buffer to quantitatively evaluate the long-term safety of the engineered barrier. Experimental research investigating the characteristics of gas migration in saturated bentonite and research developing numerical models capable of simulating such behaviors are being actively conducted worldwide. In this technical note, previous gas injection experiments and the numerical models proposed to verify such behaviors are introduced, and the future challenges necessary for the investigation of gas migration are summarized.

• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.301-309
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• 2021

In this study, we tried to improve the performance of the existing U-net-based deep learning rainfall prediction model, which can weaken the meaning of time series order. For this, ConvLSTM2D U-Net structure model considering temporal consistency of data was applied, and we evaluated accuracy of the ConvLSTM2D U-Net model using a RainNet model and an extrapolation-based advection model. In addition, we tried to improve the uncertainty in the model training process by performing learning not only with a single model but also with 10 ensemble models. The trained neural network rainfall prediction model was optimized to generate 10-minute advance prediction data using four consecutive data of the past 30 minutes from the present. The results of deep learning rainfall prediction models are difficult to identify schematically distinct differences, but with ConvLSTM2D U-Net, the magnitude of the prediction error is the smallest and the location of rainfall is relatively accurate. In particular, the ensemble ConvLSTM2D U-Net showed high CSI, low MAE, and a narrow error range, and predicted rainfall more accurately and stable prediction performance than other models. However, the prediction performance for a specific point was very low compared to the prediction performance for the entire area, and the deep learning rainfall prediction model also had limitations. Through this study, it was confirmed that the ConvLSTM2D U-Net neural network structure to account for the change of time could increase the prediction accuracy, but there is still a limitation of the convolution deep neural network model due to spatial smoothing in the strong rainfall region or detailed rainfall prediction.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.1-17
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• 2021

It is important to evaluate the fracture network in a rock volume because fractures control the ground conditions and fluid flow characteristics. Therefore, various attempts have been made to quantify fracture networks to better understand ground and flow conditions. The use of fracture density alone (a quantitative parameter based on geometric analysis) does not fully explain the evolution of fracture networks, or quantify the spatial relationship (e.g. connectivity) of fractures in a rock mass. Therefore, the need for fracture network characterization based on topological analysis has recently emerged. In Korea however, the topological analysis of fracture networks within a rock mass has rarely been studied. As such, the definition of the topological analysis of fracture networks and the graph theory related to the topological analysis are briefly summarized in this study. We also introduce an application method for these analyses to fracture characterization. If the topological method is used for the analysis of fracture networks, it can also be adopted to analyze fluid flow characteristics of groundwater, characterize petroleum reservoirs, and analyze the evolution of a fracture network. In addition, topological analysis can be useful for site selection of major facilities such as nuclear waste disposal sites because it can be used to evaluate the stability of the potential sites.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.3
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• pp.313-329
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• 2021

This study analyzed the characteristics of the management crisis, the level of resilience, and the alternatives based on the companies' self-evaluation of the game industry in Daegu. The Daegu game industry, which started spontaneously in the late 1990s, grew rapidly until the late 2000s with the support of the government and supporting organizations. However, from the mid-2010s, it has entered a period of recession due to the number of companies that failed to respond to the saturation of the mobile game market and fierce competition at home and abroad. In response, some game companies turned the crisis into an opportunity to strengthen their competitiveness by pursuing challenging strategies for product differentiation and pioneering new markets. On the other hand, companies that were passive in responding to the crisis have not get out of the management crisis. In addition, in terms of the resilience level of game companies in Daegu, the level of immediate response to shock(rapidity) and replacement of the damaged part(redundancy) was low, but the level of mobilizing sufficient resources internally(resourcefulness) was high. However, as the Daegu game industry is facing more complex multi-spatial-scale environmental changes than in the past, its resilience should be strengthened through strategies that can compensate for weaknesses in terms of the game industry ecosystem beyond individual company-level efforts.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.12
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• pp.65-76
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• 2018

Due to the rapid demographic and structural changes, Korea has faced a variety of social issues and quickly entered the aged society since the 2000s. In order deal with this reality, diverse types of welfare policies are emerging in the society as a whole. The government began to supply domestic public silver housing in 2016 to provide against the quickly growing aged society and now, the government is planning to supply approximately 50,000 housing by 2022 for quantitative growth of aged society, by selecting 1st and 2nd designated areas for the project additionally. This public retirement(silver) housing combines 'space' with 'service'. The lower floors are a public silver welfare Facilities and the upper floors are a housing spaces. This type of housing is to deal with requirements of rental housing residents by combining physical space with supporting service. Based on barrier-free design, the complex and unit house have safety handles and alarm bells in the bathroom, undulating washstands, bathroom sliding doors, corridor safety handles, and emergency safety exit lamps in each housing unit so the aged and the disabled can use easily and conveniently. Also, hand rails are installed and stepped pulleys are removed to promote convenience. Currently, the government is planning to increase the supply, focusing on low-income groups, such as beneficiaries of national basic livelihood and the working poor. Recognizing that the public retirement(silver) housing project is at its early stage, this study examined satisfaction, based on evaluations of real residents. This study aimed to obtain more empirical research data and apply them to public retirement(silver) house space analysis. For analysis, this study targeted Wirye public retirement(silver) housing and Magnolia public retirement(silver) housing that are in operation, and literature review, previous research review, and field survey were conducted to examine the present state. Using the questionnaires consisting of four large classification items; Block Layout, Housing Unit, Welfare Facilities, and Barrier-free Design, and sub-details, a survey was conducted to analyze residents' satisfaction. In conclusion, it is anticipated that this study would serve as basic research data about public retirement(silver) housing to increase continuously in future by analyzing public retirement(silver) housing spaces, on the basis of the analyzed data.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.253-265
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• 2020

As the risk of landslide is recently increasing due to the typhoons and localized heavy rains, effective techniques for the landslide damage detection are required to support the establishment of the recovery planning. This study describes the analysis of landslide-damaged areas using ISODATA(Iterative Self-Organizing Data Analysis Technique Algorithm) with Sentinel-2 image, regarding the case of Gokseong in August 7, 2020. A total of 4.75 ha of landslide-damaged areas was detected from the Sentinel-2 image using spectral characteristics of red, NIR(Near Infrared), and SWIR(Shortwave Infrared) bands. We made sure that the satellite remote sensing is an effective method to detect the landslide-damaged areas and support the establishment of the recovery planning, followed by the field surveys that require a lot of manpower and time. Also, this study can be used as a reference for the landslide management for the CAS500-1/2(Compact Advanced Satellite) scheduled to launch in 2021 and the Korean Medium Satellite for Agriculture and Forestry scheduled to launch in 2024.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.98-106
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• 2021

The paper deals with comparative study on sensitivity analysis using various methods regarding to design of experiments for structure design of an active type DSF (Deck support frame) that was developed for float-over installation of offshore plant. The thickness sizing variables of structure member of the active type DSF were considered the design factors. The output responses were defined from the weight and the strength performances. Various methods such as orthogonal array design, Box-Behnken design, and Latin hypercube design were applied to the comparative study. In order to evaluate the approximation performance of the design space exploration according to the design of experiments, response surface method was generated for each design of experiment, and the accuracy characteristics of the approximation were reviewed. The design enhancement results such as numerical costs, weight minimization, etc. via the design of experiment methods were compared to the results of the best design. The orthogonal array design method represented the most improved results for the structure design of the active type DSF.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.45-56
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• 2021

As the utilization of the underground space is activated, deep excavation of ground has been conducted for the installation of underground structures, the earth retaining wall has widely used to minimize deformation of the excavated ground. In particular, as deep excavation is actively progressing in an urban area where structures are concentrated, methods to minimize the deformation of wall have been devised to prevent damage to the structure adjacent to the wall, and one of these methods is the pre-loading method. This method is a method of suppressing the deformation of wall by actively applying a load on the strut to be installed in wall, and research on this method has been conducted recently. However, although related studies have been actively conducted, the management standard for the pre-loading of bracing has not been clearly presented until now. In addition, since the working force in the strut may increase depending on the depth of excavation or the soil condition of the backfill, the magnitude of the pre-loading that can be applied to the brace may decrease. Nevertheless, the magnitude of the pre-loading (more than 50% of the working load) proposed by the previous research results has been uniformly applied to the strut. In this study, 3D finite element analysis was performed to evaluate the application range of the pre-loading of H-beam strut according to the soil conditions of backfill. As a result of the analysis, it was found that there is a very high possibility that a problem may occur in the stability of the structure of strut due to the earth pressure and the pre-loading when the soil condition is weak and deep excavation proceeds. And it was found that the application range of the pre-loading was 5%~70% of the working load in strut.