http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ogura, Ichiro,Minami, Yoshiyuki,Ono, Junya,Kanri, Yoriaki,Okada, Yasuo,Igarashi, Kensuke,Haga-Tsujimura, Maiko,Nakahara, Ken,Kobayashi, Eizaburo Korean Academy of Oral and Maxillofacial Radiology 2021 Imaging Science in Dentistry Vol.51 No.1
Purpose: The purpose of this study was to evaluate the cone-beam computed tomographic (CBCT) imaging and histopathological characteristics of osteoradionecrosis(ORN) and medication-related osteonecrosis of the jaw(MRONJ). Materials and Methods: Ten surgical specimens from segmental mandibulectomy (3 ORN and 7 MRONJ) were analyzed using CBCT. The CBCT parameters were as follows: high-resolution mode (tube voltage, 90.0 kV; tube current, 4.00 mA; rotation time, 16.8 s; field of view, 56 mm×56 mm; thickness, 0.099 mm). Histopathological characteristics were evaluated using histological slides of the surgical specimens. The Pearson chi-square test was used to compare ORN and MRONJ in terms of CBCT findings(internal texture, sequestrum, periosteal reaction and cortical perforation) and histopathological characteristics(necrotic bone, inflammatory cells, reactive bone formation, bacteria, Actinomyces, and osteoclasts). A P value less than 0.05 was considered to indicate statistical significance. Results: MRONJ showed periosteal reaction on CBCT more frequently than ORN (7 of 7 [100%] vs. 0 of 3 [0%], P<0.05). Regarding histopathological characteristics, MRONJ showed osteoclasts more frequently than ORN (6 of 7 [85.7%] vs. 0 of 3 [0%], P<0.05). Conclusion: This study evaluated the CBCT imaging and histopathological characteristics of ORN and MRONJ, and the findings suggest that CBCT could be useful for the evaluation of ORN and MRONJ.
A note on the Trajectory Optimization of a Rigid body aircraft
Osuga Hideyo,Takano Hiroyuki,Yamasaki Takeshi,Baba Yoriaki 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
Recently, the stability and performance of the aircraft are developed in many aspects, for example, new materials, new structures, wings like the supercritical wings or the winglets, engines like the scram engines or the TVC and many control methods using computers and fly-by-wire technology, etc. Therefore, those aircraft can fly on new trajectories which used to be impossible before. These maneuvers are totally new both for pilots and engineers and should be studied to know how to fly and which abilities are required to carry out such maneuvers very well. In this paper, we formulate the vertical maneuvers of a rigid body aircraft having the post stall maneuverability with the thrust vector control as optimal trajectory problems and analyzed them with the non-linear programming. We chose the night time as the performance index and solve it as a minimum time problem. Furthermore, on the phenomenon that occurred in this analysis, we tried to reduce the number of the variables by removing one control.
Trajectory Guidance and Control for a Small UAV
Sato, Yoichi,Yamasaki, Takeshi,Takano, Hiroyuki,Baba, Yoriaki The Korean Society for Aeronautical and Space Scie 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2
The objective of this paper is to present trajectory guidance and control system with a dynamic inversion for a small unmanned aerial vehicle (UAV). The UAV model is expressed by fixed-mass rigid-body six-degree-of-freedom equations of motion, which include the detailed aerodynamic coefficients, the engine model and the actuator models that have lags and limits. A trajectory is generated from the given waypoints using cubic spline functions of a flight distance. The commanded values of an angle of attack, a sideslip angle, a bank angle and a thrust, are calculated from guidance forces to trace the flight trajectory. To adapt various waypoint locations, a proportional navigation is combined with the guidance system. By the decision logic, appropriate guidance law is selected. The flight control system to achieve the commands is designed using a dynamic inversion approach. For a dynamic inversion controller we use the two-timescale assumption that separates the fast dynamics, involving the angular rates of the aircraft, from the slow dynamics, which include angle of attack, sideslip angle, and bank angle. Some numerical simulations are conducted to see the performance of the proposed guidance and control system.
Hirotoshi Sakaida,Takeshi Yamasaki,Hiroyuki Takano,Yoriaki Baba 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
This paper presents an integrated navigation system for a guidance and control system of a small UAV The navigation part consists of GPS/INS navigation suits equipped with various MEMS sensors and a small general purpose GPS receiver, which are low cost and have been achieved the miniaturization. Since a state estimation algorithm for feedback control uses highly nonlinear equations, the Unscented Kalman Filter (UKF) which is one of the most well-known, nonlinear and maximum likelihood estimation methods, is expected to perform as an excellent filter. In this research, the possibility of the system's installment with high accuracy is researched using the UKF. The effectiveness of the integrated navigation system will be performed by several simulations, along with a series of experiments.