• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.53-60
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• 2018

This paper describes the experiments of gaze tracking utilizing a low-cost electrooculogram measuring device. The goal of the experiments is to verify whether the low-cost device can be used for a complicated human-computer interaction tool, such as the eye-writing. Two experiments are conducted for this goal: a simple gaze tracking of four directional eye-movements, and eye-writing-which is to draw letters or shapes in a virtual space. Eye-written alphabets were obtained by two PSL-iEOGs and an Arduino Uno; they were classified by dynamic positional warping after preprocessed by a wavelet function. The results show that the expected recognition accuracy of the four-directional recognition is close to 90% when noises are controlled, and the similar median accuracy (90.00%) was achieved for the eye-writing when the number of writing patterns are limited to five. In future works, additional algorithms for stabilizing the signal need to be developed.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.408-410
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• 2012

기존의 비디오 검색 방법들은 관련 주석이나 영상 정보에 기반하며 사용자의 반응과 관련하여서는 많은 정보를 활용하고 있지 않다. 비디오 시청시 사용자의 뇌신호나 시선추적 정보 등의 인지적 반응을 이용하여 연속적인 비디오 스트림의 각 부분에 대하여 사용자들이 나타내는 관심이나 감성 정보를 추출한다면 보다 인터랙티브한 비디오 데이터 검색 및 추천이 가능하다. 본 논문에서는 비디오를 시청하는 사용자의 안구전도(electrooculogram)를 기록한 후, 장면 전환이 발생한 부분에서의 사건관련전위 분석을 통해 해당 부분에서 나타나는 특징적 반응을 찾고 이에 대한 인지적 해석을 도출했다. 실험 결과 장면 전환 이후200~700ms 부분에서 P300 성분과 유사한 피크가 발생하는 것을 확인하였으며, 이러한 결과는 장면 전환에 따른 피험자의 비디오 내용 인지에 대한 의도 불일치 및 주의력 증가로 해석된다.

• The Journal of Engineering Geology
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• v.7 no.1
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• pp.37-52
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• 1997

This paper discribes the practical application of stability analysis on the revetment structures, and four different sections of revetment structures are considered in this study. As a result of stability analysis, the the section of inclined revetment with T.T.P. block shows the highest safety factor against to the sliding failure of cap concrete block, while the section of inclined revetment with rubble stone shows the highest safety factor against to the straight and circular sliding failure. And the safety factors are increased by increasing of the rigidity of covered materials and by decreasing of the slope angle. For the safety factor of overturnning and bearing capacity, the section of inclined revetment structures shows higher safety factors than the section of vertical structures, and the safety factors are increased by decreasing of the slope angle and by increasing of the bottom width of the structures.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.136-141
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• 2012

One of the main reasons for serious road accidents is driving while drowsy. For this reason, drowsiness detection and warning system for drivers has recently become a very important issue. Monitoring physiological signals provides the possibility of detecting features of drowsiness and fatigue of drivers. One of the effective signals is to measure electroencephalogram (EEG) signals and electrooculogram (EOG) signals. The aim of this study is to extract drowsiness-related features from a set of EEG signals and to classify the features into three states: alertness, drowsiness, sleepiness. This paper proposes a neural-network-based drowsiness detection system using Linear Predictive Coding (LPC) coefficients as feature vectors and Multi-Layer Perceptron (MLP) as a classifier. Samples of EEG data from each predefined state were used to train the MLP program by using the proposed feature extraction algorithms. The trained MLP program was tested on unclassified EEG data and subsequently reviewed according to manual classification. The classification rate of the proposed system is over 96.5% for only very small number of samples (250ms, 64 samples). Therefore, it can be applied to real driving incident situation that can occur for a split second.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.768-773
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• 2012

One of the main reasons for serious road accidents is driving while drowsy. For this reason, drowsiness detection and warning system for drivers has recently become a very important issue. Monitoring physiological signals provides the possibility of detecting features of drowsiness and fatigue of drivers. One of the effective signals is to measure electroencephalogram (EEG) signals and electrooculogram (EOG) signals. The aim of this study is to extract drowsiness-related features from a set of EEG signals and to classify the features into three states: alertness, drowsiness, sleepiness. This paper proposes a drowsiness detection system using Linear Predictive Coding (LPC) coefficients and Support Vector Machine (SVM). Samples of EEG data from each predefined state were used to train the SVM program by using the proposed feature extraction algorithms. The trained SVM program was tested on unclassified EEG data and subsequently reviewed according to manual classification. The classification rate of the proposed system is over 96.5% for only very small number of samples (250ms, 64 samples). Therefore, it can be applied to real driving incident situation that can occur for a split second.

• Journal of Chest Surgery
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• v.30 no.1
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• pp.92-96
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• 1997

The prognosis of Behfet's disease characterized by recurrent orogenltal ulcers and ocular and skin lesions depends upon the complications in the central nervous system, the gastrointestinal tract And the vascular system. Cardiac involvement, especially aortic regurgitation, is quite uncommon and hemodynamic instability is usually treated with ope heart surgery. But serious postoperative complications had been reported in many cases, which are prosthetic valve detachment, paravalvular leakage, conduction disturbance, and false aneurysm. Many efforts to prevent the complications have been made such as application of cryopreseved homograft. We have described an experience of root replacement with homograft in d 39 year-old male patient for prosthetic valve detachment because of Behfet's aorlitis with a review of the literatures regarding treatment, complication, and prognosis.