• Composites Research
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• v.16 no.6
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• pp.56-61
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• 2003

In this Paper, a fiber Bragg grating(FBG) sensor system is described and FBGs are well-suited for long term and extremely severe experiments, where traditional strain gauges fail. In the system. a reflect wave-length measurement method which employs a tunable light source to find out the center wave-length of FBG sensor is used. We apply the FBG system to nuclear energy Power Plant for structural integrity test to measure the displacement of the structure under designed pressure and to check the elasticity of the structure by measuring the residual strain. The system works very well and it is expected that it can be used for a real-time strain, temperature and vibration detector of smart structure.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.116-122
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• 1997

The audible noise produced by corona discharge in high voltage transmission lines is the most important line design consideration. In this paper, more accurate and useful formulas for predicting the A-weighted audible noise during heavy and light rain in alternative current (AC) transmission lines are proposed through comparison with the existing formulas. The proposed formulas are developed by the applications of evolutionary computations (ECs) to audible noise data base from long-term measurement.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2013.11a
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• pp.108-112
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• 2013

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.559-566
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• 2016

Objectives: This research has executed a new oral health promotion program among the elderly residents of a long-term care center, which purpose was to verify its effectiveness of oral health promotion through the improvement of their oral function. Methods: This study has selected the elderly over the age of 65, capable of communication, who use a long-term care center over the period of two months between July and September 2014. The subjects who remained until the final analysis numbered 50 excluding the dropouts during the program session (experimental: 33, control : 17). The oral stretching program was exercised two days a week, for total of two months. Each function was assessed by the standardized methods and measurement equipment. Also the sum of each function was converted into the oral health grade. Results: The oral function score of the experimental group also showed a statistically significant difference after the execution of the program, where the oral function score of experimental group increased $6.70{\pm}1.30$ from $4.95{\pm}0.89$ after the execution of the program (p<0.05), while the comparison group showed no valid statistical difference with the score result of $5.00{\pm}0.87$ down from $5.11{\pm}0.93$ after the execution of the program (p>0.05). Conclusions: Therefore if the oral health promotion program is reflected to the welfare policy in the future, it can be said that it contributes to the improved health status of the elderly who reside in the long-term care centers.

• Smart Structures and Systems
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• v.19 no.3
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• pp.269-277
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• 2017

Recently, there has been significant interest in structural health monitoring for civil engineering applications. In this research, a specially designed tendon, proposed by embedding FBG sensors into the center king cable of a 7-wire strand tendon, was applied for long-term health monitoring of tensile forces on a ground anchor. To make temperature independent sensors, the effective temperature compensation of FBG sensors must be considered. The temperature sensitivity coefficient ${\beta}^{\prime}$ of the FBG sensors embedded tendon was successfully determined to be $2.0{\times}10^{-5}^{\circ}C^{-1}$ through calibrated tests in both a model rock body and a laboratory heat chamber. Furthermore, the obtained result for ${\beta}^{\prime}$ was formally verified through the ground temperature measurement test, expectedly. As a result, the ground temperature measured by a thermometer showed good agreement compared to that measured by the proposed FBG sensor, which was calibrated considering to the temperature sensitivity coefficient ${\beta}^{\prime}$. Finally, four prototype ground anchors including two tension ground anchors and two compression ground anchors made by replacing a tendon with the proposed smart tendon were installed into an actual slope at the Yeosu site. Tensile forces, after temperature compensation was taken into account using the verified temperature sensitivity coefficient ${\beta}^{\prime}$ and ground temperature obtained from the Korean Meteorological Administration (KMA) have been monitored for over one year, and the results were very consistent to those measured from the load cell, interestingly.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.367-380
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• 2021

This study evaluated the stability through a three-dimensional numerical analysis method when a natural cave exists under a road in operation in Jeju Island. In order to confirm the geometric and geotechnical characteristics of the Jeju natural cave passing under the road, existing geotechnical survey reports were collected, and were studied the characteristics. In order to evaluate the effect of vehicle vibration loading on the natural cave in Jeju, three-dimensional numerical analysis was performed considering discontinuities. Through this, the stability of roads and caves with respect to vehicle speed and the depth of cover (distance from the road to the top of the natural cave) was evaluated and countermeasures were suggested. In order to secure the long-term stability of the Jeju natural cave that penetrates the lower part of the road, it was evaluated that systematic management such as long-term measurement management, reinforcement measures, and emergency measures would be necessary depending on the depth of the cover.

• Journal of Conservation Science
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• v.38 no.4
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• pp.265-276
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• 2022

A long-term monitoring investigation at Sarushima Battery (Kanagawa, Japan), which is one of the modernization heritages was conducted from 2017.06 to 2020.12. The investigation of the temperature and relative humidity (RH), measurement of the amount of brick decay, and X-ray diffraction analysis of the brick decay was conducted to understand in detail the environment in which the historical brick structure, the state of deterioration, identify the factors of deterioration. Furthermore, it was discussed whether the suitability of these investigation methods for assessing the status, identifying the level of deterioration and the factors that led to deterioration at the historical brick heritages. It was found that the brick deterioration at the site progressed especially in two periods: in April, and from June to August. These periods coincided with the period when the RH inside the structure decreased, and the Toyo-gumi bricks were in the process of absorbing moisture. Several different types of salts were detected in brick decay, especially thenardite, which is considered highly hazardous and destructive during periods when the amount of brick decay increased. Therefore, the RH in the structure and the salts present in the bricks were identified as one of the factors in the deterioration of the bricks at the site. The methods used in this study are appropriate as the initial survey methods for investigating the current conditions and identifying the causes of deterioration because it is possible to understand the environment within the modernization heritages, grasp the details of deterioration progression, and identify the characteristics of deterioration progression and its factors through long-term investigation using the simple methods.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.65-79
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• 2024

This study employs traditional statistical auto-regressive integrated moving average (ARIMA) and deep learning-based long short-term memory (LSTM) models to predict the deformation of earth retaining walls using inclinometer data from excavation sites. It compares the predictive capabilities of both models. The ARIMA model excels in analyzing linear patterns as time progresses, while the LSTM model is adept at handling complex nonlinear patterns and long-term dependencies in the data. This research includes preprocessing of inclinometer measurement data, performance evaluation across various data lengths and input conditions, and demonstrates that the LSTM model provides statistically significant improvements in prediction accuracy over the ARIMA model. The findings suggest that LSTM models can effectively assess the stability of retaining walls at excavation sites. Additionally, this study is expected to contribute to the development of safety monitoring systems at excavation sites and the advancement of time series prediction models.

• Smart Media Journal
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• v.12 no.11
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• pp.134-144
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• 2023

Nowadays, Deep Learning (DL) technology is being used in several government departments. South Korea imports a lot of seafood. If the demand for fishery products is not accurately predicted, then there will be a shortage of fishery products and the price of the fishery product may rise sharply. So, South Korea's Ministry of Ocean and Fisheries is attempting to accurately predict seafood imports using deep learning. This paper introduces the solution for the fish import prediction in South Korea using the Long Short-Term Memory (LSTM) method. It was found that there was a huge gap between the sum of consumption and export against the sum of production especially in the case of two species that are Hairtail and Pollock. An import prediction is suggested in this research to fill the gap with some advanced Deep Learning methods. This research focuses on import prediction using Machine Learning (ML) and Deep Learning methods to predict the import amount more precisely. For the prediction, two Deep Learning methods were chosen which are Artificial Neural Network (ANN) and Long Short-Term Memory (LSTM). Moreover, the Machine Learning method was also selected for the comparison between the DL and ML. Root Mean Square Error (RMSE) was selected for the error measurement which shows the difference between the predicted and actual values. The results obtained were compared with the average RMSE scores and in terms of percentage. It was found that the LSTM has the lowest RMSE score which showed the prediction with higher accuracy. Meanwhile, ML's RMSE score was higher which shows lower accuracy in prediction. Moreover, Google Trend Search data was used as a new feature to find its impact on prediction outcomes. It was found that it had a positive impact on results as the RMSE values were lowered, increasing the accuracy of the prediction.

• Korean Journal of Social Welfare
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• v.45
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• pp.126-155
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• 2001

It has been 5 years since evaluation systems were introduced to the social welfare field in Korea. More than half of social welfare agencies (617 out of 1,267) were evaluated in the past two years. Most areas of the agencies were the target of an extensive evaluation in 2000. As "the Evaluation Era" has come, problems were raised especially regarding the Accreditation system of the Ministry of Health and Social Welfare. More specifically, the problems were related to operation and management of the evaluation systems including the issue of evaluators' objectivity and fairness. In addition, evaluation costs have been too high to the government. The evaluation systems of OECD nations including the United States were quite different. These nations have used the Performance Measurement in order to secure the objectivity and the fairness. Although the quantity of information was limited compared to that of the Accreditation system, these nations have taken the lead in the governmental evaluation. In this context, this study compared social welfare evaluation systems between Korea and the United States. It presented the current status and problems of the Accreditation system of the Ministry of Health and Social Welfare, discussed the American Performance Measurement and its limitations, and compared the strengths and weaknesses of the two evaluation systems. In addition, this study suggested the strategies of Korean evaluation systems in the long term as well as in the short term.