• Journal of Korea Water Resources Association
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• v.42 no.11
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• pp.973-988
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• 2009

The objective of this study is to develop an accurate and robust two-dimensional finite element method to simulate drying and wetting in complex natural rivers. The Dry/Wet algorithm developed in this study is Grid Reconstruction Method which requires the definition of new meshes and renumbering of the nodes. Any drop of water level in the two-dimensional domain results in eliminating nodes and elements. Several numerical simulations were carried out to examine the performance of the Grid Reconstruction Method for the purpose of validation and verification of the model. The accuracy and application of the developed model are verified by comparing simulated results with observed values.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1212-1218
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• 2014

For OBC (On-Board Charger) and LDC (Low DC-DC Converter) used as essential power conversion systems of PHEV (Plug-in Hybrid Electric Vehicle), system performance is required as well as reliability, which is need to protect the vehicle and driver from various faults. While current development processor is sufficient for embodying functions and verifying performance in normal state during development of prototypes for OBC and LDC, there is no clear method of verification for various fault situations that occur in abnormal state and for securing stability of vehicle base, unless verification is performed by mounting on an actual vehicle. In this paper, a CCM (Charger Converter Module) was developed as an integrated structure of OBC and LDC. In addition, diverse fault situations that can occur in vehicles are simulated by a simulator to artificially inject into power conversion system and to test whether it operates properly. Also, HILS (Hardware-in-the-Loop Simulation) is carried out to verify whether LDC is operated properly under power environment of an actual vehicle.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.511-523
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• 2023

Research on the integration of unmanned aerial vehicles and deep learning for reinforced concrete damage detection is actively underway. Convolutional neural networks have a high impact on the performance of image classification, detection, and segmentation as backbones. The MobileNet, a pre-trained convolutional neural network, is efficient as a backbone for an unmanned aerial vehicle-based damage detection model because it can achieve sufficient accuracy with low computational complexity. Analyzing vanilla convolutional neural networks and MobileNet under various conditions, MobileNet was evaluated to have a verification accuracy 6.0~9.0% higher than vanilla convolutional neural networks with 15.9~22.9% lower computational complexity. MobileNetV2, MobileNetV3Large and MobileNetV3Small showed almost identical maximum verification accuracy, and the optimal conditions for MobileNet's reinforced concrete damage image feature extraction were analyzed to be the optimizer RMSprop, no dropout, and average pooling. The maximum validation accuracy of 75.49% for 7 types of damage detection based on MobilenetV2 derived in this study can be improved by image accumulation and continuous learning.

• Journal of the Korea Convergence Society
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• v.6 no.4
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• pp.121-126
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• 2015

Korea Youth Panel (2008) has 2 panels of the 5th year of Knowledge data to perform statistical analysis and regression analysis, the risk factors in the risk conditions of the family of functional deficits, protective factors, the relationship between the mediating effect of psychological adaptation and protective factors verification mechanisms and the psychological adaptation level it is an objective to analyze the protective factors that protect the high youth. To investigate the differences by frequency analysis and personal characteristics of the analyte's was performed t test using PASW (Predictive Analytics Software) 18.0. And to verify the effect of the parameters is performed rank regression analysis for verification of the effects of protection factors for adaptation. Rather than focusing on youth risk factors in social welfare practice field, focusing on processes and protective factors to reduce the risk factors, it is possible to convert the viewpoint overlooking the youth exposed to risk factors. Also, for young people experiencing difficulties that features loss of the family, it is determined that the prepared foundation which can be provided in the direction of social welfare practical intervention.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.6
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• pp.359-366
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• 2020

In this study, a simulation-based damage estimation method for helidecks is proposed using an artificial neural network. The structural members that share a connecting node in the helideck are regarded as a damage group, and a total of 37,400 damage scenarios are numerically generated by applying randomly assigned damage to up to three damage groups. Modal analysis is then performed for all the damage scenarios, which are selectively used as either training or validation or verification sets based on the purpose of use. An artificial neural network with three hidden layers is constructed using a PyTorch program to recognize the patterns of the modal responses of the helideck model under both damaged and undamaged states, and the network is successively trained to minimize the loss function. Finally, the estimated damage rate from the proposed artificial neural network is compared to the actual assigned damage rate using 400 verification scenarios to show that the neural network is able to estimate the location and amount of structural damage precisely.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.659-664
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• 2022

Putrescine generated by the action of microorganisms in the decay generally used as a measure of freshment in food. However, the analytical method of putrescine in freeze-dried royal jelly has not yet been established. In the present study, the UPLC method for putrescine in lyophilized royal jelly was established using C18 column. The newly established method was able to analyze putrescine accurately within 7 minutes and was validated by analytical parameters such as specificity, linearity, precision, accuracy, limit of detection, and limit of quantification. These results provide for the analytical method to evaluate the level of freshment in freeze-dried royal jelly, which will useful in further studies of safety verification.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.711-721
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• 2014

PPWS, a large number of which a main cable of a suspension bridge consists of, must be precisely erected at a target location under construction considering the differences among design conditions. The absolute sag is measured for several PPWSs, which are reference strands and the relative sag is surveyed from them to other PPWSs, which are divided into several groups. And the adjustment of PPWS length is performed to erect it at target configuration. When PPWS is being under erection in a real bridge site, the procedures are as follows; evaluate sag sensitivities according to sag variation factors, calculate an adjustment length of PPWS corresponding to them and adjust a sag of PPWS by controlling the calculated amount of PPWS length. In this study, the differential-related equations of sag sensitivity were proposed for support movement of PPWS. Before site demonstration study of a series of them, we established a catenary model system and accomplished verification tests of them. From test results, the validation of them was done.

• Smart Media Journal
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• v.7 no.3
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• pp.57-63
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• 2018

With many types of data generated in the shift of business environment as a result of growth of an organization or enterprise, there is a need to improve the data-processing efficiency in smarter means with a single domain model such as Data Lake. In particular, creating a logical single domain model from physical partitioned multi-site data by the finite resources of nature and shared economy is very important in terms of efficient operation of computing resources. Based on the advantages of the existing Data Lake framework, we define the CDA-Concept (connected data architecture concept) and functions of Data Lake Framework over Abyss Storage for integrating multiple sites in various application domains and managing the data lifecycle. Also, it performs the interface design and validation verification for Interface #2 & #3 of the connected data architecture-concept.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1049-1055
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• 2023

The utilization of agricultural drones for pest control operations has been increasing due to its economic efficiency. However, variations in the effectiveness of these operations occur depending on the operator's proficiency. In this study, we applied a smart operating mode to overcome the limitations of manual flight mode and proposed a numerical model. Through comparative validation with prior research, we conducted experimental verification. As a result, we determined the spray time and calculation of spray area for each drone model. We selected a drone for pest control with a high similarity to the numerical model and verified it experimentally. Through this, we confirmed that the application of the smart operating mode is more effective in terms of calculation of spray area and operational efficiency compared to manual flight mode.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.75-91
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• 2023

As the business-to-customer (B2C) online market expands after the COVID-19 pandemic, the logistics industry has been constructing automated warehouses to handle multi-product, low-volume logistics. When constructing a logistics automation warehouse, it is crucial to validate that the facility's performance and operational logic are designed to meet the required throughput of the automated warehouse from the system design phase. This study proposes simulation-based validation and optimal alternatives for an H logistics automation warehouse in Iksan, Jeollabuk-do. Firstly, we focused on the box supply and packing processes, which are related to the release process, among the entire logistic processes. Then, we analyzed the potential bottlenecks in the target process and designed and implemented a discrete-event simulation model based on the analysis results. The simulation experiments showed that the facility parameters and operational logic identified in the system design phase did not satisfy the performance requirements of the entire automated warehouse. Additional experiments were conducted to suggest alternatives to meet the system performance requirements by changing the facility parameters and operational logic. We expect that the proposed study will be utilized in the future, not only in the system design phase but also in the system construction phase, for verification purposes to ensure that the construction proceeds according to the design.