• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1149-1161
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• 2021

With a trend of the utilization of computer vision for satellite images, cloud detection using deep learning also attracts attention recently. In this study, we conducted a U-Net cloud detection modeling using SPARCS (Spatial Procedures for Automated Removal of Cloud and Shadow) Cloud Dataset with the image data augmentation and carried out 10-fold cross-validation for an objective assessment of the model. Asthe result of the blind test for 1800 datasets with 512 by 512 pixels, relatively high performance with the accuracy of 0.821, the precision of 0.847, the recall of 0.821, the F1-score of 0.831, and the IoU (Intersection over Union) of 0.723. Although 14.5% of actual cloud shadows were misclassified as land, and 19.7% of actual clouds were misidentified as land, this can be overcome by increasing the quality and quantity of label datasets. Moreover, a state-of-the-art DeepLab V3+ model and the NAS (Neural Architecture Search) optimization technique can help the cloud detection for CAS500 (Compact Advanced Satellite 500) in South Korea.

• Broadcasting and Media Magazine
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• v.25 no.1
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• pp.67-74
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• 2020

사용자의 건강 및 인지 상태 모니터링을 위해 다양한 생체신호를 측정 및 분석하여 예측할 수 있다. 특히 최근 상용화되고 있는 웨어러블 센서 시스템을 이용하여 손쉽게 심전도나 액티그래피 움직임 정보를 사용자로부터 일상생활 중 장시간 얻어낼 수 있다. 그러나 사용자 상태 예측을 위한 기존 생체신호 분석 모델들은 생체신호 데이터의 성질을 최대한 반영하지 못하여, 본 논문에서는 최근 급속도로 발전하고 있는 인공지능 딥러닝 기술을 이용한 극복 방안에 대해 소개한다. 상태 모니터링의 구체적인 응용 예로 사용자 스트레스 및 수면 모니터링 분석에 생체신호 데이터 기반 딥러닝 기술을 적용하여 기존 모델보다 높은 성능을 보여주고 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.538-540
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• 2021

In this paper, we proposed a smart target detection system that detects and recognizes a designated target to provide relative motion information when performing a target detection mission of a drone. The proposed system focused on developing an algorithm that can secure adequate accuracy (i.e. mAP, IoU) and high real-time at the same time. The proposed system showed an accuracy of close to 1.0 after 100k learning of the Google Inception V2 deep learning model, and the inference speed was about 60-80[Hz] when using a high-performance laptop based on the real-time performance Nvidia GTX 2070 Max-Q. The proposed smart target detection system will be operated like a drone and will be helpful in successfully performing surveillance and reconnaissance missions by automatically recognizing the target using computer image processing and following the target.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.34 no.9
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• pp.10-20
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• 2016

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.16-19
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• 2011

최근에 Smart Phone 보급의 급격한 확산에 따라 2012년경에는 국내에서 약 2천만명 정도가 Smart Phone을 사용할 것이며 전 세계적으로도 약 3억5천만대 정도의 사용자가 Smart Phone을 사용할 것으로 예상되고 있다. 이러한 Smart Phone에서 시작된 u-Device 변혁은 Smart Phone, Tablet-PC, Smart TV, Desk Top Computer를 연계한 Seamless 학습 환경 및 최근의 N-Screen 환경의 구현을 가능하게 하고 있다.

• 한국정보교육학회:학술대회논문집
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• 2007.08a
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• pp.233-239
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• 2007

최근 정보통신기술의 발달로 학교 교육 현장에서는 미래형 교육을 위한 새로운 노력들이 시도되고 있다. u-러닝 (Ubiquitous Learning)으로 일컬어지는 이러한 교육을 이끌어가는 도구로서 UMPC (Ultra Mobile Personal Computer)는 기존 PC로 할 수 있는 모든 것을 가능케 하면서 나아가 휴대성과 이동성의 장점까지 겸비해 최근 급부상하고 있다. 본 연구에서는 이러한 동향을 반영하여 평생학습 사회에서 누적된 학습을 효과적으로 관리할 수 있도록 UMPC를 기반으로 한 학습 관리 시스템을 설계하였다. 본 시스템의 장점은 다음과 같다. 첫째, 자기조절학습 이론의 자기조절학습 전략을 적용함으로써 학습자가 능동적이고 자기주도적으로 학습을 점검하고 관리할 수 있도록 하였다. 둘째, 복잡하고 불필요한 기능을 배제하고 기존의 학습 자원과 도구를 최대한 활용하여 시스템의 편의성을 높임으로써 바쁜 일상에서도 간단하게 사용할 수 있는 학습 관리 및 생활 관리 도우미의 역할을 할 수 있도록 하였다. 셋째, 자기 학습에 대한 피드백을 지속적으로 할 수 있도록 도와줌으로써 궁극적으로 학업 성취 향상에 기여할 수 있도록 하였다.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.41-47
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• 2024

Recently, as the practical application and commercialization of unmanned aerial vehicles (UAVs) is pursued, interest in ensuring the safety of the UAV is increasing. Because UAV accidents can result in property damage and loss of life, it is important to develop technology to prevent accidents. For this reason, a technique to detect the abnormal flight state of UAVs has been developed based on the AutoEncoder model. However, the existing detection technique is limited in terms of performance and real-time processing. In this paper, we propose a U-Net based abnormal flight detection technique. In the proposed technique, abnormal flight is detected based on the increasing rate of Mahalanobis distance for the reconstruction error obtained from the U-Net model. Through simulation experiments, it can be shown that the proposed detection technique has superior detection performance compared to the existing detection technique, and can operate in real-time in an on-board environment.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1273-1283
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• 2022

Recently, forest fires have frequently occurred due to climate change, leading to human and property damage every year. The forest fire monitoring technique using remote sensing can obtain quick and large-scale information of fire-damaged areas. In this study, the Gangneung and Donghae forest fires that occurred in March 2022 were analyzed using the spectral band of Sentinel-2, the normalized difference vegetation index (NDVI), and the normalized difference water index (NDWI) to classify the affected areas of forest fires. The U-net based convolutional neural networks (CNNs) model was simulated for the fire-damaged areas. The accuracy of forest fire classification in Donghae and Gangneung classification was high at 97.3% (f₁=0.486, IoU=0.946). The same model used in Donghae and Gangneung was applied to Uljin and Samcheok areas to get rid of the possibility of overfitting often happen in machine learning. As a result, the portion of overlap with the forest fire damage area reported by the National Institute of Forest Science (NIFoS) was 74.4%, confirming a high level of accuracy even considering the uncertainty of the model. This study suggests that it is possible to quantitatively evaluate the classification of forest fire-damaged area using a spectral band and indices similar to that of the Compact Advanced Satellite 500 (CAS500-4) in the Sentinel-2.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.616-617
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• 2010

This paper presents a model of e-learning based on ubiquitous computing configuration. The proposed e-learning model as following. we propose the e-learning system's hardware and software configurations which are server and networking systems. Also, we construct the proposed e-learning systems's services. There are attendance and absence service, class management service, common knowledge service, score processing service, facilities management service, personal management service, personal authorization issue management service, campus guide service, lecture-hall management service. Also, we propose the laboratory equipment management service, experimental materials management service etc.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.168-177
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• 2020

Seabed multiple reflections (seabed multiples) are the main cause of misinterpretations of primary reflections in both shot gathers and stack sections. Accordingly, seabed multiples need to be suppressed throughout data processing. Conventional model-driven methods, such as prediction-error deconvolution, Radon filtering, and data-driven methods, such as the surface-related multiple elimination technique, have been used to attenuate multiple reflections. However, the vast majority of processing workflows require time-consuming steps when testing and selecting the processing parameters in addition to computational power and skilled data-processing techniques. To attenuate seabed multiples in seismic reflection data, input gathers with seabed multiples and label gathers without seabed multiples were generated via numerical modeling using the Marmousi2 velocity structure. The training data consisted of normal-moveout-corrected common midpoint gathers fed into a U-Net neural network. The well-trained model was found to effectively attenuate the seabed multiples according to the image similarity between the prediction result and the target data, and demonstrated good applicability to field data.