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Probabilistic Prediction based Automated Driving Motion Planning Algorithm for Lane Change
Heungseok Chae,Myungsu Lee,Kyongsu Yi 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10
This paper describes design and evaluation of a motion planning algorithm of automated vehicle for lane change. Autonomous lane change is necessary for highway automated driving. In a perception part, surrounding vehicles’ states are estimated and predicted. The motion of ego vehicle is also predicted and these prediction information is utilized in motion planning. In motion planning part, driving mode, which is lane keeping or lane change, target states and constraints are decided. Lane change mode decision is determined based on surrounding vehicles states and ego vehicle states. Lane change availability is decided by the safety distance that considers relative velocity and relative position of subject and surrounding vehicles. If the ego vehicle do not perform to lane change, the most proper position is selected considering the probabilistic prediction information and the safety distance. And the longitudinal control is applied to move desired merge position. A safety driving envelope is defined based on information of surrounding vehicles behaviors and is used for control constraints. In control part, the controller is designed to obtain the desired steering angle and longitudinal acceleration using a model predictive control (MPC) with constraints. The proposed automated driving algorithm has been evaluated via computer simulation studies.
A Study on Remaining Efficiency of Thermal Straightening after Block Lifting
Ha, Yunsok,Yi, Myungsu Korean Society of Ocean Engineers 2015 Journal of advanced research in ocean engineering Vol.1 No.3
Deck plates of ships or offshore structures would make out-of-plane distortion for their thin thickness. These distortions are usually straightened by thermal straightening such as flame heating method. After thermal straightening, the blocks are lifted and moved by cranes to assemble it at dry-dock stage. After this lifting process, out-of-plane deformation again happens frequently. And then, they continuously cause quality and accuracy problems in the final dry-dock process. So, it takes more time for repair and correction working. According to preceding research, the lifting process by cranes would offset the effect on thermal straightening. The target of this study is to develop a methodology analyzing the remaining efficiency of thermal straightening after block lifting. The development was based on the assumption of yield state at straightening region. Therefore the remaining efficiency was obtained by different stiffness slope while lifting & relieving. The efficiency formula was designed using inherent strain, and we made a table of zero-efficiency by cooling speed and class rule's steels. As a result, if the stress orthogonal to straightened line is calculated during lifting analysis by FEA, the efficiency can be obtained linearly to the values in the table. Finally, even optimized carling position can be designed by considering the regional data from series project and welding region on deck.
하윤석,이명수,Ha, Yunsok,Yi, Myungsu 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.3
A very large shell-structure built in shipyards like ship hulls or offshore structures are joined by welding through full process. As the welding contains a high thermal cycle at a local area, the welded structures should be distorted unavoidably. Because a distorted ship block should be revised to the designed value before the next stage, the ability to predict and to control the weld distortion is an accuracy level of the yard itself. Despite the ship block size, several present thermal distortion methodologies can deal those sizes, but it is a different story to deal full ship size model. Even a fully constructed ship hull not remaining any welding can have an accuracy issue like outfitting installation problems. Any present thermal distortion methodology cannot accept this size for its recommended element size and the number. The ordinary welding breadth at erection stage is about 20~40 mm. It can hardly be a good choice to make finite element model of these sizes considering human effort and computational environment. The finite element model for structure analysis of a ship hull is prepared at front-end engineering design stage which is the first process of the project. The element size of the model is as fine as the longitudinal space, and it is not proper to obtain a weld distortion at the erection stage. In this study, a methodology is suggested that a weldment can be shrunk at original place instead of using structural finite element model. We cut the original shell elements at erection weld-line and put truss elements between the edges of cut elements for weld shrinkage. Additional truss elements are used to facsimile transverse weld shrinkage which cannot be from the weld-line truss element shrink. They attach to weld-line truss element like twigs from barks. The capacity of developed elements is verified through an accuracy check of erection process of a container vessel at the apt. hull. It can be a useful tool for verifying a centering accuracy after renew and for block-separating planning considering accuracy.
Split Liver Transplantation for Retroperitoneal Immature Teratoma Masquerading as Hepatoblastoma
( Dongkyu Oh ),( Nam-joon Yi ),( Hyeyoung Kim ),( Hyun-young Kim ),( Hyoung Jin Kang ),( Myungsu Lee ),( Kyoung Bun Lee ),( Kwang-woong Lee ),( Kyung-suk Suh ),( Berik Rovgaliyev ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1
Aims: Extragonadal teratoma originating from retroperitoneum represents less than 5% of all teratomas, and accounts for less than 10% of all pediatric retroperitoneal neoplasm. Until now, there is no report in the English literature about teratoma managed with liver transplantation (LT). The present study reports the case of an infant aged 3 months with retroperitoneal immature teratoma involving hepatic hilum and refractory to the chemotherapy, treated with liver transplantation. Methods: The patient was referred to our hospital for management of growing abdominal mass. The pathologic report for fine needle aspiration of the tumor lesion suggested the possibility for the hepatoblastoma with teratoid features. Cisplatin based chemotherapy was initiated at first. However, in spite of two cycles of chemotherapy, the tumor was rapidly growing with encasing the proper hepatic artery. LT was then planned, and split LT was carried out. Results: Pathological examination of explanted liver revealed the involvement of numerous neuroepithelial components, confirming the diagnosis of Norris grade III immature teratoma. Conclusions: The patient recovered well and was discharged at the 19th day after LT. He is now on postoperative day 84, under adjuvant chemotherapy based on vinblastine and doxorubicin, and the long-term outcome of a LT for immature teratoma should be followed up.
LDAPS 예측 강우를 활용한 한탄강홍수조절댐 홍수 유입량 예측
유명수,이영목,이재응,Yu, Myungsu,Lee, Youngmok,Yi, Jaeeung 한국수자원학회 2016 한국수자원학회논문집 Vol.49 No.4
최근 우리나라는 지구 온난화에 의한 기후 변화로 지역별 기후 변동뿐만 아니라 극한 기상 발생의 규모와 빈도가 커지고 있다. 2013년 장마 전선이 주로 중부지방에 위치하여 중부지방에서 강수일수 최고값을 기록하였으며, 남부지방은 강수일수 최저값을 기록하였다. 이러한 강우의 공간적, 시간적 집중 현상으로 호우 피해가 발생하여 치수의 중요성이 부각되고 있다. 본 연구에서는 홍수기 신속한 홍수 방재를 위하여 예측 강우 자료를 활용하고자 한다. 이를 위해 수치 예보 자료의 적용 가능성을 지상 관측 강우 및 유입량을 이용하여 분석하였다. 지상 관측 강우와 정량적 비교를 위해 상관계수, 최대 강우강도 퍼센트 오차 및 총 강우량 퍼센트 오차 등을 이용하였으며, 유입량은 상관계수, Nash-Sutcliffe 효율계수, 표준화된 RMSE를 사용하였다. 모의 결과 6시간까지의 상관계수는 0.7 이상으로 높은 상관성을 나타내었으며, Nash-Sutcliffe 효율계수는 6시간까지 양수를 나타내어 예측 강우의 활용 가능성을 확인할 수 있었다. Due to climate changes accelerated by global warming, South Korea has experienced regional climate variations as well as increasing severities and frequencies of extreme weather. The precipitation in South Korea during the summer season in 2013 was concentrated mainly in the central region; the maximum number of rainy days were recorded in the central region while the southern region had the minimum number of rainy days. As a result, much attention has been paid to the importance of flood control due to damage caused by spatiotemporal intensive rainfalls. In this study, forecast rainfall data was used for rapid responses to prevent disasters during flood seasons. For this purpose, the applicability of numerical weather forecast data was analyzed using the ground observation rainfall and inflow rate. Correlation coefficient, maximum rainfall intensity percent error and total rainfall percent error were used for the quantitative comparison of ground observation rainfall data. In addition, correlation coefficient, Nash-Sutcliffe efficiency coefficient, and standardized RMSE were used for the quantitative comparison of inflow rate. As a result of the simulation, the correlation coefficient up to six hours was 0.7 or higher, indicating a high correlation. Furthermore, the Nash-Sutcliffe efficiency coefficient was positive until six hours, confirming the applicability of forecast rainfall.