为实现避碰时机的选择,在船舶自主航行决策阶段需建立符合《1i972年国际海上避碰规则》和良好船艺的碰撞危险度模型。首i先,基于MMG(Mathematcal Model Group)和模糊PID(Proportion Integral Differental)航向控制器,建立自适应航向控...为实现避碰时机的选择,在船舶自主航行决策阶段需建立符合《1i972年国际海上避碰规则》和良好船艺的碰撞危险度模型。首i先,基于MMG(Mathematcal Model Group)和模糊PID(Proportion Integral Differental)航向控制器,建立自适应航向控制模型,模拟船舶非线性转向运动过程;解析局面要素的物理含义,建立求解局面要素模型;根据不同局面,计算可避让他船的最小改向角;最后,以反映会遇局面客观属性的最小改向角模型为基础,提出碰撞危险度单一指标模型并仿真验证。仿真表明,提出的碰撞危险度符合航海实践,能展示多船会遇局面下不同时刻的碰撞危险度并演绎变化规律。模型能够实现单船会遇时避碰时机的判断,多船会遇时优先避让目标的确定,为自主航行奠定坚实理论基础。展开更多
为提高海上搜救效率,提出一种基于船舶操纵运动数学模型研究小组(Ship Manoeuvring Mathematical Model Group,MMG)模型的船舶动态扇形自动搜寻模式。在充分考虑风、流等外界扰动影响的基础上,不需要额外进行风、流等漂流模型的推算,以M...为提高海上搜救效率,提出一种基于船舶操纵运动数学模型研究小组(Ship Manoeuvring Mathematical Model Group,MMG)模型的船舶动态扇形自动搜寻模式。在充分考虑风、流等外界扰动影响的基础上,不需要额外进行风、流等漂流模型的推算,以Matlab软件中Simulink模块为工具进行仿真。仿真结果表明:在不依赖GPS船位的前提下,船舶的航向、舵角、航速均符合航海实践要求。该搜寻模式可提高应对海上突发事故的搜救能力,从而减少突发事故中的人员伤亡和财产损失。展开更多
中国五矿与澳大利亚OZ矿业公司的交易17日完成交割。OZ矿业经结算调整获得13．54亿美元资金，而五矿获得OZ矿业大部分核心矿产。在完成收购后，五矿将在澳洲注册成立一家新公司——Minemlsand Mining Group Limited（MMG），以管理开发...中国五矿与澳大利亚OZ矿业公司的交易17日完成交割。OZ矿业经结算调整获得13．54亿美元资金，而五矿获得OZ矿业大部分核心矿产。在完成收购后，五矿将在澳洲注册成立一家新公司——Minemlsand Mining Group Limited（MMG），以管理开发这些资产。展开更多
Mechanomyography (MMG) acquires the oscillatory waves of contracting muscles. Electromyography (EMG) is a tool for monitoring muscle overall electrical activity. During muscle contractions, both techniques can investi...Mechanomyography (MMG) acquires the oscillatory waves of contracting muscles. Electromyography (EMG) is a tool for monitoring muscle overall electrical activity. During muscle contractions, both techniques can investigate the changes that occur in the muscle properties. EMG and MMG parameters have been used for detecting muscle fatigue with diverse test protocols, sensors and filtering. Depending on the analysis window length (WLA), monitoring physiological events could be compromised due to imprecision in the determination of parameters. Therefore, this study investigated the influence of WLA variation on different MMG and EMG parameters during submaximal isometric contractions monitoring MMG and EMG parameters. Ten male volunteers performed isometric contractions of elbow joint. Triaxial accelerometer-based MMG sensor and EMG electrodes were positioned on the biceps brachii muscle belly. Torque was monitored with a load cell. Volunteers remained seated with hip and elbow joint at angles of 110° and 90°, respectively. The protocol consisted in maintaining torque at 70% of maximum voluntary contraction as long as they could. Parameter data of EMG and the modulus of MMG were determined for four segments of the signal. Statistical analysis consisted of analyses of variance and Fisher’s least square differences post-hoc test. Also, Pearson’s correlation was calculated to determine whether parameters that monitor similar physiological events would have strong correlation. The modulus of MMG mean power frequency (MPF) and the number of crossings in the baseline could detect changes between fresh and fatigued muscle with 1.0 s WLA. MPF and the skewness of the spectrum (μ3), parameters related to the compression of the spectrum, behaved differently when monitored with a triaxial MMG sensor. The EMG results show that for the 1.0 s and 2.0 s WLAs have normalized RMS difference with fatigued muscle and that there was strong correlation between parameters of different domains.展开更多
文摘为实现避碰时机的选择,在船舶自主航行决策阶段需建立符合《1i972年国际海上避碰规则》和良好船艺的碰撞危险度模型。首i先,基于MMG(Mathematcal Model Group)和模糊PID(Proportion Integral Differental)航向控制器,建立自适应航向控制模型,模拟船舶非线性转向运动过程;解析局面要素的物理含义,建立求解局面要素模型;根据不同局面,计算可避让他船的最小改向角;最后,以反映会遇局面客观属性的最小改向角模型为基础,提出碰撞危险度单一指标模型并仿真验证。仿真表明,提出的碰撞危险度符合航海实践,能展示多船会遇局面下不同时刻的碰撞危险度并演绎变化规律。模型能够实现单船会遇时避碰时机的判断,多船会遇时优先避让目标的确定,为自主航行奠定坚实理论基础。
文摘为提高海上搜救效率,提出一种基于船舶操纵运动数学模型研究小组(Ship Manoeuvring Mathematical Model Group,MMG)模型的船舶动态扇形自动搜寻模式。在充分考虑风、流等外界扰动影响的基础上,不需要额外进行风、流等漂流模型的推算,以Matlab软件中Simulink模块为工具进行仿真。仿真结果表明:在不依赖GPS船位的前提下,船舶的航向、舵角、航速均符合航海实践要求。该搜寻模式可提高应对海上突发事故的搜救能力,从而减少突发事故中的人员伤亡和财产损失。
基金CNPq and CAPES for the financial support and grants received.
文摘Mechanomyography (MMG) acquires the oscillatory waves of contracting muscles. Electromyography (EMG) is a tool for monitoring muscle overall electrical activity. During muscle contractions, both techniques can investigate the changes that occur in the muscle properties. EMG and MMG parameters have been used for detecting muscle fatigue with diverse test protocols, sensors and filtering. Depending on the analysis window length (WLA), monitoring physiological events could be compromised due to imprecision in the determination of parameters. Therefore, this study investigated the influence of WLA variation on different MMG and EMG parameters during submaximal isometric contractions monitoring MMG and EMG parameters. Ten male volunteers performed isometric contractions of elbow joint. Triaxial accelerometer-based MMG sensor and EMG electrodes were positioned on the biceps brachii muscle belly. Torque was monitored with a load cell. Volunteers remained seated with hip and elbow joint at angles of 110° and 90°, respectively. The protocol consisted in maintaining torque at 70% of maximum voluntary contraction as long as they could. Parameter data of EMG and the modulus of MMG were determined for four segments of the signal. Statistical analysis consisted of analyses of variance and Fisher’s least square differences post-hoc test. Also, Pearson’s correlation was calculated to determine whether parameters that monitor similar physiological events would have strong correlation. The modulus of MMG mean power frequency (MPF) and the number of crossings in the baseline could detect changes between fresh and fatigued muscle with 1.0 s WLA. MPF and the skewness of the spectrum (μ3), parameters related to the compression of the spectrum, behaved differently when monitored with a triaxial MMG sensor. The EMG results show that for the 1.0 s and 2.0 s WLAs have normalized RMS difference with fatigued muscle and that there was strong correlation between parameters of different domains.
