• Journal of Korea Water Resources Association
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• v.55 no.2
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• pp.111-120
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• 2022

The concept of soil moisture memory was used as a method for quantifying the function of soil to control water flow, which evaluates the average residence time of precipitation. In order to characterize the soil moisture memory, a new measurement index called stored precipitation fraction (F_p(f)) was used by tracking the increments in soil moisture by the precipitation event. In this study, the temporal and spatial distribution of soil moisture memory was evaluated along with the slope and soil characteristics of the surface (0~5 cm) soil by using satellite- and model-based precipitation and soil moisture in the Korean peninsula, from 2019 to 2020. The spatial deviation of the soil moisture memory was large as the stored precipitation fraction in the soil decreased preferentially along the mountain range at the beginning (after 3 hours), and the deviation decreased overall after 24 hours. The stored precipitation fraction in the soil clearly decreased as the slope increased, and the effect of drainage of water in the soil according to the composition ratio of the soil particle size was also shown. In addition, average soil moisture contributed to the increase and decrease of hydraulic conductivity, and the rate of rainfall transfer to the depths affected the stored precipitation fraction. It is expected that the results of this study will greatly contribute in clarifying the relationship between soil moisture memory and surface characteristics (slope, soil characteristics) and understanding spatio-temporal variation of soil moisture.

• Smart Structures and Systems
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• v.29 no.4
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• pp.625-640
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• 2022

Maglev rail joints are vital components serving as connections between the adjacent F-type rail sections in maglev guideway. Damage to maglev rail joints such as bolt looseness may result in rough suspension gap fluctuation, failure of suspension control, and even sudden clash between the electromagnets and F-type rail. The condition monitoring of maglev rail joints is therefore highly desirable to maintain safe operation of maglev. In this connection, an online damage detection approach based on three-dimensional (3D) convolutional neural network (CNN) and time-frequency characterization is developed for simultaneous detection of multiple damage of maglev rail joints in this paper. The training and testing data used for condition evaluation of maglev rail joints consist of two months of acceleration recordings, which were acquired in-situ from different rail joints by an integrated online monitoring system during a maglev train running on a test line. Short-time Fourier transform (STFT) method is applied to transform the raw monitoring data into time-frequency spectrograms (TFS). Three CNN architectures, i.e., small-sized CNN (S-CNN), middle-sized CNN (M-CNN), and large-sized CNN (L-CNN), are configured for trial calculation and the M-CNN model with excellent prediction accuracy and high computational efficiency is finally optioned for multiple damage detection of maglev rail joints. Results show that the rail joints in three different conditions (bolt-looseness-caused rail step, misalignment-caused lateral dislocation, and normal condition) are successfully identified by the proposed approach, even when using data collected from rail joints from which no data were used in the CNN training. The capability of the proposed method is further examined by using the data collected after the loosed bolts have been replaced. In addition, by comparison with the results of CNN using frequency spectrum and traditional neural network using TFS, the proposed TFS-CNN framework is proven more accurate and robust for multiple damage detection of maglev rail joints.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.103-112
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• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Journal of Consumption Culture
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• v.15 no.3
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• pp.67-90
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• 2012

When consumers choose healthy foods, they base their buying decisions on health-related food labeling and quality assessment of taste, health, and price. Moreover, both purchase experience and opinions of family and friends affect consumer choices. Focusing on these points, this study examined the effects of health-related food labeling on consumer choices by adding two variables-quality assessment of taste, health, and price and purchase experience-to the model of the theory of planned behavior. We also used structural equation modeling to test our hypotheses. In the study, health-related food labeling includes organic labeling, nutrient claims, and food additive labeling. We conducted a mail survey among 300 married women who buy cheese slices for their children more than once a month. It was discovered that health-related food labeling positively affected the level of quality assessment of taste, health, and price, and consequently led to positive attitudes and purchase intentions. Particularly, health-related food labeling positively influenced attitude toward using products without assessing the quality of taste, health, and price. The level of quality assessment of price positively affected attitude toward using and purchasing products, and purchase experience positively affected attitude toward using and purchasing products, and purchase intentions. The relationship between attitude to purchasing products and purchase intentions was the most positive, and the relationship between perceived behavioral control and purchase intentions was not significant. Overall, this study essentially contributes to the development of a theoretical framework of food labeling and consumer choices, which includes quality assessment of taste, health, and price and purchase experience, by using the theory of planned behavior.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.99-110
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• 2009

Objectives : The current treatment regimens for patients with nephrotic syndrome due to membranous nephropathy(MN) are based on steroids or immunosuppressive therapy with the aim of reducing proteinuria and improving outcome. Although these treatments attenuate the deterioration of renal function in MN patients, it has been suggested that all are burdened by significant toxicity. Therefore, more specific and less toxic therapies are needed. This study was to evaluate the effects of Coptidis Rhizoma Extract(CRE) on the MN induced by cBSA in mice. Methods : Mice were divided into 4 groups. One group named for 'Normal' was injected with a saline solution not to be immunized. The rest groups were treated as follows; After mice were immunized with 0.2 mg of cBSA and Freund's complete adjuvant one time every two weeks for 6 weeks, they received intra-peritoneal injection of 10 mg/kg of cBSA daily for 4 weeks. Also, they were divided into 3 groups. The first named for 'Control' was not given CRE. The second for 'CRE-250' was given oral administration of 250 mg/kg of CRE daily for 4 weeks. The third for 'CRE-500' was given 500 mg/kg of CRE. All of mice were sacrificed 4 weeks after the first immunization. We measured a body weight and 24hrs proteinuria as well as serological analysis. The morphologic changes of renal glomeruli were also observed with a light microscope and an electron microscope. Results : The levels of 24 hrs proteinuria, triglyceride, IgG, IL-6 were significantly decreased in both CRE groups. And the level of IgM was significantly decreased in CRE-250 group. In histological findings of kidney tissue, thickening of GBM and deposition of electron-density were consideraly decreased in both CRE groups. Conclusions : The present study suggests that CRE is highly effective when treating mice with MN induced by cBSA. More clinical data and studies are to be done for efficient application.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.111-123
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• 2023

The slope of an open cut tunnel is located above the exit of the Leijia tunnel on the Changgan high-speed railway. During the excavation of the open cut tunnel foundation pit, the slope slipped twice, a large landslide of 92500 m³ formed. The landslide body and unstable slope body not only caused the foundation pit of the open cut tunnel to be buried and the anchor piles to be damaged but also directly threatened the operational safety of the later high-speed railway. Therefore, to study the stability change in the slope of the open cut tunnel under heavy rain and excavation conditions, a 3D numerical calculation model of the slope is carried out by Midas GTS software, the deformation mechanism is analyzed, anti-sliding measures are proposed, and the effectiveness of the anti-sliding measures is analyzed according to the field monitoring results. The results show that when rainfall occurs, rainwater collects in the open cut tunnel area, resulting in a transient saturation zone on the slope on the right side of the open cut tunnel, which reduces the shear strength of the slope soil; the excavation at the slope toe reduces the anti-sliding capacity of the slope toe. Under the combined action of excavation and rainfall, when the soil above the top of the anchor pile is excavated, two potential sliding surfaces are bounded by the top of the excavation area, and the shear outlet is located at the top of the anchor pile. After the excavation of the open cut tunnel, the potential sliding surface is mainly concentrated at the lower part of the downhill area, and the shear outlet moves down to the bottom of the open cut tunnel. Based on the deformation characteristics and the failure mechanism of the landslides, comprehensive control measures, including interim emergency mitigation measures and long-term mitigation measures, are proposed. The field monitoring results further verify the accuracy of the anti-sliding mechanism analysis and the effectiveness of anti-sliding measures.

• Smart Media Journal
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• v.11 no.11
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• pp.17-24
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• 2022

With the spread of smart speakers based on voice recognition technology and deep learning technology, not only non-disabled people, but also the blind or physically handicapped can easily control home appliances such as lights and TVs through voice by linking home network services. This has greatly improved the quality of life. However, in the case of speech-impaired people, it is impossible to use the useful services of the smart speaker because they have inaccurate pronunciation due to articulation or speech disorders. In this paper, we propose a personalized voice classification technique for the speech-impaired to use for some of the functions provided by the smart speaker. The goal of this paper is to increase the recognition rate and accuracy of sentences spoken by speech-impaired people even with a small amount of data and a short learning time so that the service provided by the smart speaker can be actually used. In this paper, data augmentation and one cycle learning rate optimization technique were applied while fine-tuning ResNet18 model. Through an experiment, after recording 10 times for each 30 smart speaker commands, and learning within 3 minutes, the speech classification recognition rate was about 95.2%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.789-798
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• 2008

The stiffness method provides a framework to calculate the structural deformations directly from solving the equilibrium state. However, to use the displacement shape functions leads to approximate estimation of stiffness matrix and resisting forces, and accordingly results in a low accuracy. The conventional flexibility method uses the relation between sectional forces and nodal forces in which the equilibrium is always satisfied over all sections along the element. However, the determination of the element resisting forces is not so straightforward. In this study, a new fiber finite element mixed method has been developed for nonlinear anaysis of steel-concrete composite structures in the context of a standard finite element analysis program. The proposed method applies the Newton method based on the load control and uses the incremental secant stiffness method which is computationally efficient and stable. Also, the method is employed to analyze the steel-concrete composite structures, and the analysis results are compared with those obtained by ABAQUS. The comparison shows that the proposed method consistently well predicts the nonlinear behavior of the composite structures, and gives good efficiency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.89-100
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• 2010

The performance evaluation of a conventional Wave Resonator at the entrance of harbors against solitary wave has been performed using 3D numerical wave flume. A wave resonator has been designed for the attenuation of the transmitted wave energy by trapping the short periodic incident waves only. In this study, however, the controlled performance of the wave resonator by its various widths has been numerically investigated for solitary waves. Source distribution method based on the Green function and the 3D one-field Model for immiscible TWO-Phase flows (TWOPM-3D) using 3D numerical wave flume were used for the short-periodic waves and the solitary waves, respectively, and these models were verified through the comparisons with the previous experimental and numerical results by other researchers. It was confirmed that the wave resonator is effective enough to control the solitary waves as well as the periodic waves when it compares with the case of no resonance system. Further, it was found that there is the optimal width of a wave resonator to attenuate the target solitary waves.

• Korean Journal of School Psychology
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• v.16 no.3
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• pp.283-313
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• 2019

The purpose of this study was to develop and examine the effectiveness of 'Coping Resources Improvement Program' designed for emerging adults experiencing psychosocial difficulties during college to work transition. Based on transition model of Scholossberg(1995), the program was developed to intervene in 4S (Situation, Self, Support, Strategy) required in the transition. Participants included 31 job applicants who are senior or above and were assigned to the experimental group (N=10), comparison group (N=10), and control group (N=11). Data to verify effectiveness were collected pre-, mid-, and post treatment. Results indicated that the level of coping resources and psychosocial difficulties in the transition changed significantly after the program and those changes were still maintained after a month in the experimental group. However, there were no statistically significant changes on job-search burnout and career-adaptability in all groups. The implication and limitation of the study and the suggestions for the future studies were discussed.