人体测量与人体模型第(二讲)

人体尺寸是人机系统或产品设计的基本资料.通过人体测量可获取人体的静态尺寸和人体动态尺寸.人体的静态尺寸是结构尺寸,而人体的动态尺寸是功能尺寸,后者包括操作者在工作姿势或某种操作活动状态下测量的尺寸.人体测量学通过测量人体各部位尺寸确定个体之间和群体之间在人体尺寸上的差别,用来研究人的形态,为工业产品造型设计和人机环境系统工程设计提供人体测量数据.     

一种新型ZigBee无线ECG采集分析系统

无线ECG心电采集和分析系统是一种新兴的、有广阔发展前景的医疗器械.基于CC2530 ZigBee模块和Cortex M3处理器,设计并实现了远距离无线心电采集分析系统.该系统采集人体心电信号,通过CC2530模块建立ZigBee网络,将采集节点采到的信号发送到协调器.协调器再将信号送至Cortex M3高性能处理器显示和处理,供医疗人员初步分析诊断,系统还可将ECG信号送至上位机作进一步处理和分析.本系统具有抗干扰能力强、可靠性好、功耗低、体积小等特点,可以广泛应用于医院和社区医疗站等.     

基于云端的口袋式人体脉搏诊断仪

脉搏波所呈现出的形态、强度、速率和节律等方面的综合信息,反映了人体心血管系统的众多生理病理信息.现代医学通过脉搏波获取心血管动力学参数,我国传统医学通过脉搏诊断人体各个器官、经络的健康状况.本系统采用科学的手法采集并分析脉搏波,光电容积脉搏波描述法因其无创、便宜、方便等优点,在评估血液动力学参数方面应用较多.尤其是用于血氧饱和度、血压以及心输出量的测量.本系统在光电容积描述法采集脉搏波信号后利用专业算法,提取心血管动力学参数的同时结合传统医学分析人体12经络健康状况,最后将历史数据保存并通过TCP远程共享.     

电子式互感器数据分析系统的设计与应用

在分析电子式互感器的工作原理及其数字信号输出格式的基础上,详细设计并实现了基于WinPCap网络工具包的新型电子式互感器数据分析系统.该系统可对采样报文进行精确的实时捕获分析,并以动态波形图的方式显示瞬时的采样波形,为电子式互感器性能测试、极性校验等系列试验提供了有效的辅助分析工具.     

电力系统可视化技术

介绍了可视化技术在电力系统潮流和最优潮流分析中应用的最新成果.讨论了应用动态变尺寸饼图和动画潮流箭头显示电力系统潮流;以及应用等高线显示母线电压和边际电价.此外,还讨论了交互式三维动画技术在电力系统可视化中的应用.所提出的可视化技术不但可用于离线潮流和最优潮流分析,而且可用于电力系统控制中心在线潮流和最优潮流分析.     

含电动机负荷的互联电力系统动态等值模型可辨识性分析

对大型互联电力系统进行动态等值可以显著地降低计算分析的工作量,但目前电力系统动态等值多采用简单模型,存在不能很好地反映系统动态特性的问题.为此,提出同时考虑发电机凸极效应和电动机负荷特性的动态等值模型来进行可辨识性分析.以两区域互联系统为例,首先给出计及发电机凸极特性和电动机负荷的区域系统动态等值模型,然后对非线性模型进行线性化.采用基于拉普拉斯变换的传递函数法分析模型的可辨识性.利用系统稳态条件,从理论上证明了所提出的动态等值模型的所有参数均是可以辨识的.     

基于Agent室内环境控制系统建模研究

在分析建筑室内环境主要参数的基础上,选择动态窜内温度、预测平均投票率、人体感知空气质量和审内照度作为控制目标,使用基于Agent的建模技术对室内环境系统进行层次分析,提出了4种类型的Agent模型,并详细阐述了4种模型的构造.建立了基于Agent的室内环境控制系统,并分析了系统中Agent之间的交互关系.     

超宽带信号在运动人体下阴影衰落对 通信性能的影响

超宽带信号在人体通信技术中具有低功耗、抗衰减等优势。针对人体信道建模工作中阴影衰落与运动状态关联性的问题,文章基于人体不同运动姿态与组织电磁特性建立人体模型,分析超宽带信号下的动态人体信道阴影衰落特性。首先,通过建立80条数据传播链路分析人体不同状态下的体表传播特性,给出了一种体表传播距离与路径损耗的二阶指数衰减关系。其次,分析了动态模型组织电特性变化对路径损耗的影响情况。最后,使用平均误码率研究了UWB系统在动态阴影衰落下的性能差异。结果表明,在动态人体模型下UWB频段的抗损耗性能优于HBC频段,其阴影衰落强度受运动状态影响程度强于HBC频段。研究对超宽带信号在人体通信的建模、应用工作中提供了动态人体阴影衰落强度分布的理论基础。     

基于虚拟仪器的生理信号检测与处理系统

利用虚拟仪器技术构建一台实验动物生理信号检测与处理系统.该系统设有八个通道,可分别对实验动物的体温、呼吸、血压、心电等生理信号进行检测和处理.利用LabWindows/CVI软件结合PCI-9112数据采集卡对动物的生理信号进行实时、高速的采集,同时借助计算机的强大功能对采集到的数据进行显示、处理、存储和回放.实验证明系统运行稳定,检测精度高,有一定的实用价值.     

超级电容器动态参数采集系统的研究

设计了一个基于虚拟仪器的动态参数采集系统,以实现对超级电容器动态参数的同步采集和状态评估。介绍了传感器的选型、信号调理电路的设计以及PXI设备同步性的实现,采用Lab View编程实现对实时数据的采集、显示、存储、分析处理等功能。试验结果表明,整个采集系统可以同步、安全、可靠地采集多节超级电容动态特性参数,可作为参数辨识和状态评估的依据。     

遗传算法优化BP神经网络的非接触式血压估计方法

血压是人体重要的生理参数,能够反应心脏泵血功能、外周血管阻力、血容,对其进行非接触连续测量在日常生活和诸多应用场合中具有很重要的意义。从面部视频中获取相关脉搏波信号,然后提取信号中与血压相关性高的特征参数,从而利用这些参数建立血压估计的神经网络模型,并采用遗传算法对其进行优化。通过验证得出遗传算法优化BP神经网络(GA-BP)模型估计能力和拟合精度明显提高,且其估计结果满足相应血压测量标准并能实现血压非接触连续估计,其收缩压估计准确率为93.1%,舒张压估计准确率为96.6%。故通过脉搏波特征参数建立GA-BP模型是一种有效非接触式血压估计方法。     

The first accurate measurement of systolic and diastolic bloodpressure

Poiseuille, known for his law of fluid flow, which is the analog of Ohm's law, introduced the units (mmHg) by which we measure blood pressure by using the mercury manometer, which he described in his medical school thesis in 1828. For 50 years, mean blood pressure was all that could be measured because of the long response time of the mercury manometer. It is true that the height of the mercury column displayed pulsatile oscillations, but their amplitude was much less than that of pulse pressure. It is interesting to note that the slowly responding mercury manometer was made to display first systolic then diastolic pressure by means of an ingenious device that contained two oppositely directed check valves. It took from 1828 to 1903 for high-fidelity graphic recordings of blood pressure to appear in which systolic and diastolic pressures were believable. However, systolic and diastolic pressures were measurable since 1878 when Golz and Gaule created their ingenious valved device that permitted use of the slowly responding mercury manometer to display these pressures accurately     

基于柯氏音识别法的自动血压测量系统

市场上的电子血压计一般均采用示波法,采用间接测量原理,其准确性难以提高;柯氏音法是血压测量的金标准,有望提高自动血压测量准确性,但柯氏音的降噪和识别是难题。因此,提出了基于柯氏音识别法的自动血压测量系统,该系统解决了降噪和识别的难题,通过对实时柯氏音信号的测试表明该系统可以有效地识别出柯氏音,得出收缩压和舒张压,识别精度高。且该系统成本低廉,可操作于Android系统的手机上,易于实现社区血压的健康管理和远程监控。     

Constrained long-range adaptive predictive control of arterial blood pressure

An adaptive blood pressure control system based on the long-range or finite-time-horizon prediction strategy known as generalized predictive control has been examined. The system was designed to run as a real-time, multitasking operating system providing real-time monitoring and control of mean arterial pressure. The ability to control in the presence of constraints was also incorporated into the system. Results from both unconstrained and constrained control runs were obtained from experiments on aneasthetized dogs. The problems caused by model-plant mismatch, varying time delays and non-linearity were handled satisfactorily by the system. The disturbance rejection of the constrained algorithm is better than the unconstrained one. The results demonstrate the applicability of both the constrained and unconstrained generalized predictive control algorithm for regulation of mean arterial pressure.     

Measurement of external pressures generated by nerve cuff electrodes.

When external pressures are applied to a peripheral nerve, tissue damage can occur via compression and blood flow occlusion, resulting in degeneration and demyelination of axons. Although many types of nerve electrodes have been designed to avoid or minimize this pressure during stimulation of the nerve or recording of its activity, the measurement of the pressure exerted by these cuffs has not been reported. Currently, only theoretical models are used to predict nerve cuff electrode pressures. We have developed a nerve cuff electrode pressure sensor to measure external pressures exerted by peripheral nerve cuff electrodes. The sensor has a high sensitivity, linear response with little hysteresis and reproducible output. Pressure measurements have been obtained for split-ring and spiral cuff electrodes. The measurements obtained are in agreement with theoretical predictions. Moreover, they indicate that the pressures exerted by cuffs currently used for stimulation generate only a small amount of pressure, which is below the pressure required to occlude blood flow in nerves. The results also suggest that this new sensor can provide reliable measurement of external pressures exerted by nerve electrodes and would be an important tool for comparing various nerve cuff electrode designs.     

Autonomic neural control of cerebral hemodynamics

Despite the rich innervation of the cerebral vasculature by both sympathetic and parasympathetic nerves [1], the role of autonomic control in cerebral circulation and, particularly, cerebral hemodynamics is not entirely clear [2]. Previous animal studies have reported inconsistent results regarding the effects of electrical stimulation or denervation on cerebral blood flow (CBF), cerebral pressureflow relationship, and cerebral vessel response to metabolic stimuli [3]--[5]. Moreover, with the advance of transcranial Doppler ultrasound (TCD), which yields accuratemeasurements of CBF velocity (CBFV) with high time resolution [6], it has been found that in humans CBFV in the middle cerebral artery decreased substantially during lower body negative pressure (LBNP) and head-up tilt in the absence of systemic hypotension, which suggests the presence of cerebral vasoconstriction associated with augmented sympathetic nerve activity during orthostatic stress [7]. These observations were based on assessing static measures of cerebral circulation, i.e., mean values of artevial blood pressure (ABP) and CBF with a low time resolution.     

状态机识别算法在柯氏音血压系统中的研究

基于柯氏音法的血压测量系统,相较于采用示波法的电子血压计,有着更为科学和准确的优点。其原理是将测量柯氏音的过程录入到电脑中,并且实时识别和测量出柯氏音及血压值。但由于识别处理算法的限制,容易遗漏或误判个别柯氏音,导致柯氏音的识别和血压的测量始终存在误差。因此,提出利用状态机识别算法,从而改进血压测量系统的方法,并在理论上分析了该方法的正确性,通过一系列的实验测试表明该方法不仅识别精度高,解决了遗漏个别柯氏音的难题,并且稳定性也非常好,从而保证了能够进一步将血压测量系统开发到手机平台,将其推广到更多的应用场合。     

252kV SF_6断路器空载时压力特性试验研究

为了研究灭弧室中物性参数的动态特性,笔者对高压SF6断路器在空载状态下压气缸与喷口喉部的压力特性进行了测试,得到压气缸与喷口喉部气体压力的特性曲线。分析了压力变化与开断时间的关系,比较了不同基压下压气缸与喷口喉部气体压力特性的变化,说明了基压对断路器灭弧室内压力的影响。     

A lumped parameter mathematical model to analyze the effects of tachycardia and bradycardia on the cardiovascular system

In this study, the cardiovascular system and heart hemodynamic performance are modeled using lumped method (electrical analogy) to evaluate the effects of abnormal heartbeats on the cardiovascular system performance. Lumped method (voltage–current relations of an electrical circuit) is able to simulate the cardiovascular (CV) system behavior in various physiological conditions. CV system consists of 42 compartments, including artery, vein, capillary set, and heart chambers. Each blood circulatory subsystem (compartment) is modeled using electrical elements, such as resistor, capacitor, and inductor. In this study, by utilizing lumped model, CV system is simulated in matlab software (SIMULINK environment). There are two major types of irregular heart rates. In tachycardia, the heartbeats are too quick: over 100 beats per minute. In bradycardia, the heart beat is too slow: less than 60 beats per minute. Healthy blood circulation and heart performance are modeled (heartbeat: 75 beat/minute), and the results such as left atrium outflow‐time graph and pressure‐time diagram of aorta artery and pulmonary circulation are obtained. The present results are found to be in agreement with numerical and experimental studies. Then, by increasing and decreasing the heartbeat, the abnormality (150 and 50 beat/minute representing tachycardia and bradycardia, respectively) is simulated. The results show that the tachycardia leads to a significant reduction of capillary blood flow into less than 100 ml/s, while it exceeds 100 ml/s when heart has normal function. The results of the present study have clinical implications for detailed diagnosis of CV diseases when experimental studies have limitation. Copyright © 2014 John Wiley & Sons, Ltd.