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- 저자 : Xianxiang Chen (검색결과 2 건)
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Chen Guoliang,Wei Fuxin,Li Jiachun,Shi Liangyu,Zhang Wei,Wang Xianxiang,Xu Zuofeng,Liu Xizhe,Zou Xuenong,Liu Shaoyu 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.7
Objective: To analyze the correlations between intraoperative ultrasound and MRI metrics of the spinal cord in degenerative cervical myelopathy and identify novel potential predictive ultrasonic indicators of neurological recovery for degenerative cervical myelopathy. Materials and Methods: Twenty-two patients who underwent French-door laminoplasty for multilevel degenerative cervical myelopathy were followed up for 12 months. The Japanese Orthopedic Association (JOA) scores were assessed preoperatively and 12 months postoperatively. Maximum spinal cord compression and compression rates were measured and calculated using both intraoperative ultrasound imaging and preoperative T2-weight (T2W) MRI. Signal change rates of the spinal cord on preoperative T2W MRI and gray value ratios of dorsal and ventral spinal cord hyperechogenicity on intraoperative ultrasound imaging were measured and calculated. Correlations between intraoperative ultrasound metrics, MRI metrics, and the recovery rate JOA scores were analyzed using Spearman correlation analysis. Results: The postoperative JOA scores improved significantly, with a mean recovery rate of 65.0 ± 20.3% (p < 0.001). No significant correlations were found between the operative ultrasound metrics and MRI metrics. The gray value ratios of the spinal cord hyperechogenicity was negatively correlated with the recovery rate of JOA scores (ρ = -0.638, p = 0.001), while the ventral and dorsal gray value ratios of spinal cord hyperechogenicity were negatively correlated with the recovery rate of JOA-motor scores (ρ = -0.582, p = 0.004) and JOA-sensory scores (ρ = -0.452, p = 0.035), respectively. The dorsal gray value ratio was significantly higher than the ventral gray value ratio (p < 0.001), while the recovery rate of JOA-motor scores was better than that of JOA-sensory scores at 12 months post-surgery (p = 0.028). Conclusion: For degenerative cervical myelopathy, the correlations between intraoperative ultrasound and preoperative T2W MRI metrics were not significant. Gray value ratios of the spinal cord hyperechogenicity and dorsal and ventral spinal cord hyperechogenicity were significantly correlated with neurological recovery at 12 months postoperatively.
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Robust Optimal Trajectory Design by Integrating Genetic Algorithm with Min-Max Method
Jianmei Song,Xianxiang Chen,Zhiyong Liu,Jing Zhang 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.5
A robust optimal trajectory design method is proposed in this paper. Genetic Algorithm (GA) is employed to optimize the whole trajectory to improve the terminal attack performance. To enhance the robustness of the trajectory to disturbances, the min-max method is integrated into the GA optimization process. The proposed approach is carefully illustrated with the robust optimization de-sign of the trajectory for a portable short-range top-attack (PSRTA) missile. The H∞ robust gain-scheduled technique is used to design the attitude tracking autopilot to facilitate the trajectory design. The damp feedback loop of the weakly-damped missile body is innovatively treated as the Linear Pa-rameter Varying system (the controlled plant), which is good for practical use. The proposed robust op-timal trajectory design method and the H∞ robust gain-scheduled attitude tracking autopilot are demonstrated to be effective from the whole trajectory simulation results of the PSRTA missile, which also exhibit high applicability for practical engineering problems.
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