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Yunxi Zhang,Yu Fan,Mingwei Sun,Zenghui Wang,Zengqiang Chen 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.1
The high-speed anti-ship missile might encounter a challenge in the terminal phase if there are mixed targets, including false and true ones. There is only a quite short time to take action after the onboard radar can distinguish which targets are true or false. In this study, a tunable acceleration feedback gain is used to realize a unique integrated guidance and control scheme in a natural way by maintaining advantages of the traditionally practical proportional navigation and three-loop acceleration autopilot without introducing additional dynamics as the existing methods in the literature. The gain range can be determined using a numerical calculation scheme. The adjoint method is employed to reveal the advantage of the tunable gain and can then obtain the optimal gain. The proposed method can achieve a trade-off between the effective navigation gain and the settling time of the autopilot during the integration. Extensive simulations are performed to validate the appealing discovery. This philosophy offers guideline for the renovation of existing anti-ship missiles.
Cameron Dietiker,김소은,Yunxi Zhang,Chadwick W. Christine 대한파킨슨병및이상운동질환학회 2019 Journal Of Movement Disorders Vol.12 No.2
ObjectiveIn Parkinson’s disease (PD), vitamin B12 levels are lower, and comorbid B12 deficiency has been associated with the development of neuropathy and early gait instability. Because little is known about B12 supplement use in PD, we sought to evaluate its use in a large PD cohort and, as an exploratory analysis, to determine whether baseline characteristics or disease progression differed according to B12 supplementation. MethodsWe utilized data collected as part of the National Institutes of Health Exploratory Trials in PD (NET-PD) Long-term Study (LS-1), a longitudinal study of 1,741 participants. We stratified subjects into 4 groups according to daily supplement use: no B12, multivitamin (MVI) containing < 100 μg B12, B12 ≥ 100 μg, and MVI + B12 ≥ 100 μg. Clinical outcomes were assessed at 3 years for each group using the Unified Parkinson’s Disease Rating Scale (UPDRS), its subscores, and selected individual questions. ResultsOf the 1,147 participants who completed the 3-year visit, 41% took an MVI, 2% took B12, 3% took MVI + B12, and 54% reported taking no supplements. At 3 years, no significant differences in clinical outcomes were observed. However, there was a trend toward lower hazard ratios for developing sensory symptoms (UPDRS Item 17) in the MVI (p = 0.08) and B12 + MVI (p = 0.08) groups compared to that in the no supplement group. ConclusionThese results show that supplementation with vitamin B12 ≥ 100 μg is uncommon in early PD. The finding of a trend toward a lower hazard ratio for the development of sensory symptoms in those taking an MVI or B12 + MVI warrants further study.