• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2019.08a
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• pp.192-192
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• 2019

• Journal of the Korean Society for Railway
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• v.5 no.3
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• pp.148-157
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• 2002

A health monitoring system becomes a useful tool to obtain information on long term behavior of the important railway structures such as very long span and special type bridges. The health monitoring system not only gives the direct measurement data of the railway bridges but also provides the basic data on the maintenance of the structures. Therefore, periodic calibrations of the health monitoring system will be a necessary step toward precise and accurate assessment of the railway bridges. In this study, the calibration and gauge factor readjustment process made for the health monitoring system installed in the railroad bridges is reviewed and some findings are explained in detail: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in full length. Based on the regression results, it was found that the gauge factors need to be readjusted according to the regression equation but, since the deviation or shift is not serious so far, long-term observation on each sensor is also recommended. Future work will be concentrated on the long-term analysis of each sensor and on the database creation so that the assessment of the structures is possible.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.469-476
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• 2022

This study developed a Recurrent Neural Network model implemented through Long Short-Term Memory (LSTM) that generates long-term tidal level data at Busan Port using tide observation data. The tide levels in Busan Port were predicted by the Korea Hydrographic and Oceanographic Administration (KHOA) using the tide data observed at Busan New Port and Tongyeong as model input data. The model was trained for one month in January 2019, and subsequently, the accuracy was calculated for one year from February 2019 to January 2020. The constructed model showed the highest performance with a correlation coefficient of 0.997 and a root mean squared error of 2.69 cm when the tide time series of Busan New Port and Tongyeong were inputted together. The study's finding reveal that long-term tidal level data prediction of an arbitrary port is possible using the deep learning recurrent neural network model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.4
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• pp.109-118
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• 2022

The data of the missing section among the vertex surface sea temperature observation data was imputed using the Bidirectional Recurrent Neural Network(BiRNN). Among artificial intelligence techniques, Recurrent Neural Networks (RNNs), which are commonly used for time series data, only estimate in the direction of time flow or in the reverse direction to the missing estimation position, so the estimation performance is poor in the long-term missing section. On the other hand, in this study, estimation performance can be improved even for long-term missing data by estimating in both directions before and after the missing section. Also, by using all available data around the observation point (sea surface temperature, temperature, wind field, atmospheric pressure, humidity), the imputation performance was further improved by estimating the imputation data from these correlations together. For performance verification, a statistical model, Multivariate Imputation by Chained Equations (MICE), a machine learning-based Random Forest model, and an RNN model using Long Short-Term Memory (LSTM) were compared. For imputation of long-term missing for 7 days, the average accuracy of the BiRNN/statistical models is 70.8%/61.2%, respectively, and the average error is 0.28 degrees/0.44 degrees, respectively, so the BiRNN model performs better than other models. By applying a temporal decay factor representing the missing pattern, it is judged that the BiRNN technique has better imputation performance than the existing method as the missing section becomes longer.

• Korean Journal of Child Studies
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• v.28 no.6
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• pp.53-72
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• 2007

The purpose of this study was to understand the meaning and nature of long term boarding care of children provided by grandparents in surrogate foster homes. Data were collected from 10 children 15 to 18 years of age by in depth interviews and observation from May 2007 to July 2007. Analysis of data was by the phenomenological analytic method of Giorgi(1970). Seven essential themes were extracted: (1) ambivalence about being labeled "family headed by a child," (2) recognition of the burden to grandparents with appreciation for their care, (3) resentment and yearning for parents, (4) economic hardship, (5) discord with grandparents, (6) maladjustment to school life, and (7) overcoming such obstacles as poor economic conditions and loneliness.

• Korean Journal of Plant Tissue Culture
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• v.27 no.3
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• pp.233-238
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• 2000

To obtain a basic information of the development of Genus Viola, morphological and histological observation of in vitro calli and cells in Viola culture cells were investigated. There were two callus types obtained by long term subculture of wild viola (Viola partrinii DC. ) petiole callus. One was friable callus - soft and pale green in color and small cells in size, and the other was compact callus - compact and deep bluish green in color, large cells in size. In scanning electron microscopic observation, friable callus was composed of voculated cell around small. cell clump, while compact callus was composed of cells filled with protoplasm Somatic embryogenesis was observed from suspension culture of the compact callus.

• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.151-156
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• 2012

Purpose: The purpose of this study was to investigate the adverse effects of sensorimotor function at the shoulder joint according to long-term cane usage in stroke patients without apraxic behavior, in terms of the presence of shoulder joint pain, accuracy of tracking task, proprioceptive joint position sense, and nine-hole pegboard. Methods: Nineteen stroke patients with long-term cane usage (cane usage group) and nineteen stroke patients without cane usage (non-cane usage group) were recruited. All subjects were tested in pain presence, a tracking task for visuomotor function, joint reposition, and nine-hole pegboard in the shoulder joint regarding the non-affected side. Results: In the accuracy index for tracking task and the nine-hole pegboard test, significant differences were observed between the cane usage group and the non-cane usage group. However, although a higher emergence of shoulder pain and a lower accuracy for joint reposition sense were detected in the cane usage group in comparison to the non-cane usage group, there were no significant differences between the two groups. Conclusion: Our findings suggest that long-term cane usage could induce to decrease in delicate movement and coordination in the non-affected upper arm in stroke patients. In addition, they could experience high frequency of shoulder pain and poor joint reposition sense. Therefore, careful evaluation and observation will be required concerning stroke patients with long-term cane usage.

• Atmosphere
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• v.34 no.1
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• pp.69-81
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• 2024

In this paper, Annual flux variations in the Boseong Tall Tower (BTT) from 2016 to 2020 were analyzed using data from three levels (2.5 m, 60 m, and 300 m). BTT was installed in Boseong-gun, Jeollanam-do in February 2014 and continued to conduct energy exchange observations such as CO2, sensible heat, and latent heat using the eddy covariance method until March 2023. The BTT was located in a very flat and uniform paddy field, and flux observations were conducted at four levels: 2.5 m, 60 m, 140 m, and 300 m above ground. Surface energy balance was confirmed from observed data of net radiation flux, soil heat flux, sensible heat flux, and latent heat flux. Additionally, 2.5 m height surface fluxes, which are most influenced by agricultural land, were compared with data from Local Data Assimilation and Prediction System (LDAPS) of the Korea Meteorological Administration to evaluate the accuracy of LDAPS flux data. The correlation coefficient between LDAPS flux data and observed values was 0.95 or higher. Excluding summer latent heat flux data, there was a general tendency for LDAPS data to be higher than observed values. The footprint areas estimated below 60 m height mainly covered agricultural land, and flux observations at 2.5 m and 60 m heights showed typical agricultural characteristics. In contrast, the footprint estimated at 300 m height did not show agricultural characteristics, indicating that observations at this height encompassed a wide range, including mountains, sea, and roads. The analysis results of long-term flux observations can contribute to understanding the energy and carbon dioxide fluxes in agricultural fields. Furthermore, these results can be utilized as essential data for validating and improving numerical models related to such fluxes.

• Journal of Korean Elementary Science Education
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• v.24 no.4
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• pp.345-350
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• 2005

The purpose of this study was to identify observation methods, observation targets and their changes in elementary school students' observing aquariums. Silurus microdorsalis, Orthrias nudus, Iksookimia rotundicaudata and Semisulcospira bensoni in two aquariums were observed for 40 minutes in every week during 10 weeks by elementary children. Students' observation methods and targets were analyzed with their observation diary. Also the change of observation methods and targets on each species were analysed based on the observation diary. This study found the facts which was change of observation methods and observation targets according to observable theme of each species as time goes by. The results also found children's various methods and targets in observing living objects and observation methods were changed variously during 10 week-observation. The results of this study may provide more various and systematic norm and assessment criteria for teaching observation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.427-430
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• 2003

Yi-dong experimental site is operated for research on the rural basin characteristics and accumulation of a long term data by hydrological observation equipments. This basin area is 9,300ha, length 14.4km and slope 0.67%. Hydrological observation network has 3 rainfall meter3, 3 reservoir storage levels and 2 river water levels.