• Nuclear Engineering and Technology
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• 제55권2호
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• pp.493-505
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• 2023

Comprehensive condition monitoring of large industry systems such as nuclear power plants (NPPs) is essential for safety and maintenance. In this study, we developed novel system-scale diagnostic technology based on deep-learning and IR thermography that can efficiently and cost-effectively classify system conditions using compact Raspberry Pi and IR sensors. This diagnostic technology can identify the presence of an abnormality or accident in whole system, and when an accident occurs, the type of accident and the location of the abnormality can be identified in real-time. For technology development, the experiment for the thermal image measurement and performance validation of major components at each accident condition of NPPs was conducted using a thermal-hydraulic integral effect test facility with compact infrared sensor modules. These thermal images were used for training of deep-learning model, convolutional neural networks (CNN), which is effective for image processing. As a result, a proposed novel diagnostic was developed that can perform diagnosis of components, whole system and accident classification using thermal images. The optimal model was derived based on the modern CNN model and performed prompt and accurate condition monitoring of component and whole system diagnosis, and accident classification. This diagnostic technology is expected to be applied to comprehensive condition monitoring of nuclear power plants for safety.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.603-604
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• 2021

주차장에서 일어날 수 있는 비매너 주차로 인한 충돌을 사전에 예방하기 위한 단속시스템이다. 주차장에서 일어날 수 있는 장애인, 전기차 전용 주차구역에 일반차량 주차, 2개 차선을 물고 주차하는 차량이 있다. 위와 같은 차량을 딥러닝 객체인식 기능을 통해 비매너 주차를 감지하여 알려준다. 비매너 주차 상황이 찍힌 사진이나 영상을 학습데이터로 사용하여 상황을 인식할 수 있도록 학습데이터를 제작하고 그 상황을 인식하여 비매너 주차 유무를 판단한다. 주차장의 환경을 좀 더 쾌적하게 함으로써 주차장 이용자간 충돌을 줄이는데 목적이 있다.

• Smart Structures and Systems
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• 제32권1호
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• pp.37-47
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• 2023

Indirect determination of pan evaporation (PE) has been highly regarded, due to the advantages of intelligent models employed for this objective. This work pursues improving the reliability of a popular intelligent model, namely multi-layer perceptron (MLP) through surmounting its computational knots. Available climatic data of Fresno weather station (California, USA) is used for this study. In the first step, testing several most common trainers of the MLP revealed the superiority of the Levenberg-Marquardt (LM) algorithm. It, therefore, is considered as the classical training approach. Next, the optimum configurations of two metaheuristic algorithms, namely cuttlefish optimization algorithm (CFOA) and teaching-learning-based optimization (TLBO) are incorporated to optimally train the MLP. In these two models, the LM is replaced with metaheuristic strategies. Overall, the results demonstrated the high competency of the MLP (correlations above 0.997) in the presence of all three strategies. It was also observed that the TLBO enhances the learning and prediction accuracy of the classical MLP (by nearly 7.7% and 9.2%, respectively), while the CFOA performed weaker than LM. Moreover, a comparison between the efficiency of the used metaheuristic optimizers showed that the TLBO is a more time-effective technique for predicting the PE. Hence, it can serve as a promising approach for indirect PE analysis.

• Geomechanics and Engineering
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• 제37권6호
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• pp.629-641
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• 2024

The presence of excavations or cavities beneath the foundations of a building can have a significant impact on their stability and cause extensive damage. Traditional methods for calculating the bearing capacity and subsidence of foundations over cavities can be complex and time-consuming, particularly when dealing with conditions that vary. In such situations, machine learning (ML) and deep learning (DL) techniques provide effective alternatives. This study concentrates on constructing a prediction model based on the performance of ML and DL algorithms that can be applied in real-world settings. The efficacy of eight algorithms, including Regression Analysis, k-Nearest Neighbor, Decision Tree, Random Forest, Multivariate Regression Spline, Artificial Neural Network, and Deep Neural Network, was evaluated. Using a Python-assisted automation technique integrated with the PLAXIS 2D platform, a dataset containing 272 cases with eight input parameters and one target variable was generated. In general, the DL model performed better than the ML models, and all models, except the regression models, attained outstanding results with an R² greater than 0.90. These models can also be used as surrogate models in reliability analysis to evaluate failure risks and probabilities.

• 정보교육학회논문지
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• 제26권3호
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• pp.175-186
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• 2022

정부는 감염병 사태를 극복하고 이로 인한 학습공백을 메우기 위해 다양한 정책적 제언과 관련 법령을 정비하는 등 원격수업 혁신 의지를 내비쳤다. 이러한 흐름에 발맞추고자 이 연구는 원격수업의 유형을 구분하고, 대학 학습자를 대상으로 원격수업의 유형에 따라 어떠한 차이가 있는지 규명하였다. 이를 위해 서울 소재 K대학교 569명의 학습자 대상으로 설문을 실시하였으며, 수집된 결과는 빈도분석, 신뢰도 및 타당도 검증, 검정, 다중회귀분석 등으로 통계분석 처리되어 다음과 같은 결론과 시사점이 도출되었다. 첫째, 동시적 원격수업의 학습지속의향을 촉진시키는 요인으로 지각된 유용성이 도출되었다. 따라서 해당 수업에 대한 적절한 교수전략 탐색, 안정적인 인프라 구축과 같은 다양한 전략을 안배하여 학습자의 인식을 개선시켜 주어야 할 필요가 있다. 둘째, 비동시적 원격수업의 학습지속의향을 촉진시키는 요인으로 지각된 유용성, 사회실재감, 시스템품질이 도출되었다. 그러므로 해당 수업에 대한 유용성 인식개선뿐만 아니라, 원만한 상호작용과 적시 피드백, 강의 품질관리가 수반되어야 학습자의 학습지속의향이 촉진될 것이다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.131-131
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• 2021

Deep learning models, especially those based on long short-term memory (LSTM), have presented their superiority in addressing time series data issues recently. This study aims to comprehensively evaluate the performance of deep learning models that belong to the supervised learning category in streamflow prediction. Therefore, six deep learning models-standard LSTM, standard gated recurrent unit (GRU), stacked LSTM, bidirectional LSTM (BiLSTM), feed-forward neural network (FFNN), and convolutional neural network (CNN) models-were of interest in this study. The Red River system, one of the largest river basins in Vietnam, was adopted as a case study. In addition, deep learning models were designed to forecast flowrate for one- and two-day ahead at Son Tay hydrological station on the Red River using a series of observed flowrate data at seven hydrological stations on three major river branches of the Red River system-Thao River, Da River, and Lo River-as the input data for training, validation, and testing. The comparison results have indicated that the four LSTM-based models exhibit significantly better performance and maintain stability than the FFNN and CNN models. Moreover, LSTM-based models may reach impressive predictions even in the presence of upstream reservoirs and dams. In the case of the stacked LSTM and BiLSTM models, the complexity of these models is not accompanied by performance improvement because their respective performance is not higher than the two standard models (LSTM and GRU). As a result, we realized that in the context of hydrological forecasting problems, simple architectural models such as LSTM and GRU (with one hidden layer) are sufficient to produce highly reliable forecasts while minimizing computation time because of the sequential data nature.

• 치위생과학회지
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• 제23권2호
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• pp.93-102
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• 2023

Background: To investigate political participation by dental hygiene students and analyze the differences therein based on the learning efficacy of dental hygiene policy. Methods: A total of 239 dental hygiene students who were expected to graduate responded to the survey. The data were collected online using a structured questionnaire consisting of 6 items on general characteristics, 10 on political participation, and 15 on the learning efficacy of dental hygiene policy. Statistical analysis was performed using SPSS 23.0. Political participation based on the learning efficacy of dental hygiene policy was analyzed using independent t-tests, ANOVA, and multiple regression analysis (p<0.05). Results: Among the dental hygiene students, 60.7% voted in all three recent presidential, general, and local elections, and 14.2% did not. For political parties supported, 65.7% responded that they had "no supporting party," and 34.3% indicated that they had a "supporting party." In terms of the level of political participation of dental hygiene students (0~50 points), the average score was 25.8 points, with the average passive political participation (0~25 points) score at 15.6 points and the average active political participation (0~25 points) score at 10.2 points. With an increase in dental hygiene policy learning efficacy, both passive and active political participation showed higher scores (p<0.05). Conclusion: Dental hygiene students showed low political participation. The presence of a supporting party, higher voting participation, and higher learning efficacy of dental hygiene policy were associated with higher passive and active political participation. Therefore, to increase this population's interest in political participation, various opportunities for related learning need to be promoted and provided in academia, leading to the enhancement of their political capabilities. In this manner, dental hygienists should expand their capabilities in various roles such as advocates, policy makers, and leaders.

• 정보화정책
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• 제31권1호
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• pp.32-52
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• 2024

이 연구는 가상현실 에이전트 외국어 강사를 활용한 외국어 학습 효과를 검증하는 것을 목표로 한다. 외국어 학습맥락을 고려해 가상현실 에이전트를 원어민과 비원어민으로 구분해 이를 실험자 간 요인으로, 에이전트의 역할은 교사와 판매원으로 나누어 실험자 내 요인으로 설정한 후, 몰입형 가상환경 콘텐츠를 직접 개발하고, 2×2 혼합요인설계를 하여 실험을 진행했다. 자발적으로 참여한 72명의 대학생을 대상으로 실험을 한 결과, 학습만족감, 기억, 회상에서 에이전트의 원어민 여부와 역할간 상호작용 효과가 통계적으로 유의미하게 나타났으나, 학습자신감, 프레즌스는 상호작용 효과와 주효과 모두에서 유의미한 차이를 보이지 않았다. 가상환경에서의 맥락적 학습이 학습 효과와 만족감을 증진한다는 결과와 에이전트의 역할이 학습자의 기억에 영향력을 미친다는 결과는 가상현실 에이전트 외국어 강사를 활용한 외국어 학습 효과의 유효성을 증명한 것으로, 가상현실 에이전트를 활용한 다양한 처치 결과가 학습자의 인지 및 정서적 반응에 긍정적 효과를 줄 수 있다는 중요한 이론적, 실증적 함의를 제공한다.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.137-145
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• 2020

Providing safety training to construction workers is essential to reduce safety accidents at the construction site. With the prosperity of visualization technologies, Immersive Virtual Reality (IVR) has been adopted for construction safety training by providing interactive learning experiences in a virtual environment. Previous research efforts on IVR-based training have found that the level of fidelity of interaction between real and virtual worlds is one of the important factors contributing to the sense of presence that would affect training performance. Various interactive devices that link activities between real and virtual worlds have been applied in IVR-based training, ranging from existing computer input devices (e.g., keyboard, mouse, joystick, etc.) to specially designed devices such as high-end VR simulators. However, the need for high-fidelity interactive devices may hinder the applicability of IVR-based training as they would be more expensive than IVR headsets. In this regard, this study aims to understand the impact of the level of fidelity of interactive devices in the sense of presence in a virtual environment and the training performance during IVR-based forklift safety training. We conducted a comparative study by recruiting sixty participants, splitting them into two groups, and then providing different interactive devices such as a keyboard for a low fidelity group and a steering wheel and pedals for a high-fidelity group. The results showed that there was no significant difference between the two groups in terms of the sense of presence and task performance. These results indicate that the use of low-fidelity interactive devices would be acceptable for IVR-based safety training as safety training focuses on delivering safety knowledge, and thus would be different from skill transferring training that may need more realistic interaction between real and virtual worlds.

• 한국콘텐츠학회논문지
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• 제21권1호
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• pp.292-310
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• 2021

COVID 19의 영향이 교육계에도 직접적인 영향을 미치고 있다. 특히, 비대면 수업이 선택이 아닌 필수가 된 상황에서 실시간 화상강의에 대한 학습자의 만족과 이용의도를 높일 수 있는 방안에 대해 관심이 높아지고 있다. 본 연구에서는 화상강의 특성으로서 학습자-교수자 간 상호작용성, 사회적 실재감, 이용가능성, 자기효능감, 참여정도가 인지된 유용성과 이용 용이성, 학습 만족과 화상강의 이용의도에 영향을 미치는지 분석하였다. 연구결과, 인지된 이용 용이성에는 학습자-교수자 상호작용성과 이용가능성, 자기효능감이 정적인 영향을 미치는 것으로 나타났으며, 인지된 유용성에는 이용가능성을 제외한 모든 변인이 정적인 영향을 미치는 것으로 확인되었다. 또한, 인지된 유용성과 이용 용이성은 학습 만족과 화상강의 이용의도를 높이는 요인인 것으로 확인되었으며, 학습 만족 역시 화상강의 이용의도에 정적인 영향을 미치는 주요 변인인 것으로 나타났다. 본 연구는 실증적인 분석을 통해 향후 많은 교육 현장에서 활용하게 될 실시간 화상강의에 대해 여러 이론적, 실천적 시사점을 제공했다는 점에 의의가 있다.