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금속 음영이 포함된 CBCT 영상에서 딥러닝을 이용한 해부학적 구조물의 다중 클래스 분할 방법
양수(Su Yang),천소영(Soyoung Chun),김다엘(Dael Kim),전보성(Bo Soung Jeoun),유지용(Jiyong Yoo),강세룡(Se-Ryong Kang),최민혁(Min-Hyuk Choi),김조은(Jo-Eun Kim),허경회(Kyung-Hoe Huh),이삼선(Sam-Sun Lee),허민석(Min-Suk Heo),이원진(Won-Jin Y 대한전기학회 2022 전기학회논문지 Vol.71 No.1
In order to perform preoperative surgical planning, accurate segmentation of anatomical structures in cone-beam computed tomography (CBCT) images is required. However, this image segmentation is often impeded by metal artifacts, and it takes a lot of time due to morphological variability in patients. In this paper, we proposed a deep learning based automatic multi-class segmentation method for anatomical structures in CBCT images containing metal artifacts. Four U-Net based deep learning models were used for anatomical structure segmentation. Each deep learning model was constructed by changing the encoder of U-Net architecture to the backbones (DenseNet121, VGGNet16, ResNet101, and EfficienNetB4). For training and testing our method, we used 20744 CBCT images containing metal artifacts from 30 patient datasets. Experimental results show that the segmentation performances of the mandible, midfacial bone, mandibular canal, and maxillary sinus were achieved F1 scores of 0.912±0.070, 0.880±0.080, 0.687±0.265, and 0.954±0.063 using DenseNet121 with Tversky loss, respectively. Furthermore, our method was able to perform robust and accurate segmentation of anatomical structures in CBCT images containing metal artifacts.
Lee, Su-Yong,Park, Jiyong,Kim, Jaewan,Noh, Changsuk American Physical Society 2017 Physical review. A Vol.95 No.1
<P>We investigate quantum nonlocality of a single-photon entangled state under feasible measurement techniques consisting of on-off and homodyne detections along with unitary operations of displacement and squeezing. We test for a potential violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality, in which each of the bipartite party has a freedom to choose between two measurement settings, with each measurement yielding a binary outcome. We find that single-photon quantum nonlocality can be detected when two or less of the four total measurements are carried out by homodyne detection. The largest violation of the CHSH inequality is obtained when all four measurements are squeezed-and-displaced on-off detections. We test the robustness of violations against imperfections in on-off detectors and single-photon sources, finding that the squeezed-and-displaced measurement schemes perform better than the displacement-only measurement schemes.</P>
김수겸(Su-Kyum Kim),유명종(Myoung-Jong Yu),최지용(Jiyong Choi),이재원(Jae-Won Lee) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5
2020년대에 계획되어 있는 한국형 달착륙선을 성공적으로 개발하기 위해서는 추진기관의 성능, 자세 제어, 착륙 장치의 성능 등을 검증하기 위한 지상 검증 시험을 수행할 필요가 있으며 이러한 지상 검증 시험을 위한 추력기 및 추진시스템의 설계/제작이 현재 진행 중에 있다. 본 논문에서는 현재 진행중인 200N급 추력기의 설계 및 제작 결과 및 지상 시험용 추진시스템 기본 설계를 소개할 예정이다. For the successful development of korean lunar lander, the ground test is required in order to verify performance of propulsion system, attitude control system, performance of landing device and etc. In order to develop the lunar lander ground test model, development of large size thruster and pressure regulated propulsion system is now in progress. In this paper, the results of 200N class monopropellant thruster development and propulsion system design will be presented.
치아 크라운 질량 중심 및 각도 자동 예측을 위한 PointNet++ 기반 방법
천소영(Soyoung Chun),양수(Su Yang),유지용(Jiyong Yoo),최민혁(MinHyuk Choi),강세룡(Se-Ryong Kang),최시은(Sieun Choi),전보성(Bosoung Jeoun),김진(Jin Kim),이원진(Wonjin Yi) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
환자별 임플란트 크라운을 설계하기 위해서는 환자별 치아 위치, 치아 각도, 상악과 하악 사이의 교합 등을 고려해야 한다. 본 연구에서는 임플란트 크라운 설계를 위한 환자 임상치 크라운의 질량 중심과 각도 단위 벡터를 자동으로 예측하는 수정된 PointNet++를 제안하였다. 결과적으로 우리의 방법이 환자 맞춤형 임플란트 크라운의 자동 설계에 적용되기를 기대한다.
Sung Woo Shin,Jiyong Lee,Jeong-Su Kim,Joonwoo Shin 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.1
The stress dependence of ultrasonic wave velocity is known as the acoustoelastic effect. This effect is useful for stress monitoring if the acoustoelastic coefficient of a subject medium is known. The acoustoelastic coefficients of metallic materials such as steel have been studied widely. However, the acoustoelastic coefficient of concrete has not been well understood yet. Basic constituents of concrete are water, cement, and aggregates. The mix proportion of those constituents greatly affects many mechanical and physical properties of concrete and so does the acoustoelastic coefficient of concrete. In this study, influence of the water-cement ratio (w/c ratio) and the fine-coarse aggregates ratio (fa/ta ratio) on the acoustoelastic coefficient of concrete was investigated. The w/c and the fa/ta ratios are important parameters in mix design and affect wave behaviors in concrete. Load-controlled uni-axial compression tests were performed on concrete specimens. Ultrasonic wave measurements were also performed during the compression tests. The stretching coda wave interferometry method was used to obtain the relative velocity change of ultrasonic waves with respect to the stress level of the specimens. From the experimental results, it was found that the w/c ratio greatly affects the acoustoelastic coefficient while the fa/ta ratio does not. The acoustoelastic coefficient increased from 0.003073 MPa-1 to 0.005553 MPa-1 when the w/c ratio was increased from 0.4 to 0.5. On the other hand, the acoustoelastic coefficient changed in small from 0.003606 MPa-1 to 0.003801 MPa-1 when the fa/ta ratio was increased from 0.3 to 0.5. Finally, it was also found that the relative velocity change has a linear relationship with the stress level of concrete.