Effects of avatar character performances in virtual reality dramas used for teachers’ education

Virtual reality drama has the benefit of enhancing immersion, which was lacking in original e-Learning systems. Moreover, dangerous and expensive educational content can be replaced by stimulating users’ interest. In this study, we investigate the effects of avatar performance in virtual reality drama. The hypothesis that the psychical distance between virtual characters and their viewers changes according to the size of video shots is tested with an autonomic nervous system function test. Eighty-four college students were randomly assigned to three groups. Virtual reality drama is used to train teachers concerning school bullying prevention, and deals with the dialogue between teachers and students. Group 1 was provided with full-shot video clips, Group 2 was shown various clips from full shots to extreme close-ups, and Group 3 was provided with close-up shots. We found that the virtual reality drama viewers’ levels of stimulation changed in relation to the size of the shots. The R-R (between P wave and P wave) intervals of the electrocardiograms (ECGs, bio-signal feedback) became significantly narrower as the shot size became smaller.     

基于互信息最小的非线性混合胎儿心电信号提取方法

胎儿心电信号提取具有重要的临床意义。目前大多数胎儿心电信号提取方法是基于线性瞬时混合模型,使用多路信号实现.本文基于更符合实际情况的非线性混合模型,使用两路心电信号,提出一种新颖的从母体腹部混合信号中提取胎儿心电信号方法。首先,在假定母体和胎儿两个心电信号相互独立的基础上,基于互信息最小原则,提出一种新的目标函数;然后,利用多层感知机拟合母体心电信号传导至腹部所经历的非线性变换,从而得到母体腹部混合信号中母体心电成分的最优估计;最后,从母体腹部混合信号中减去母体心电信号的最优估计,实现胎儿心电信号的成功提取。实验结果验证了该方法的正确性和有效性。     

基于高阶统计量的心电信号R波检测

心电信号的检测对于临床心脏疾病的检验和确诊有很重要的作用,所以目前有关心电信号检测方法的研究很多。本文针对心电信号R波的检测,采用了一种基于高阶统计量的检测方法。使用MATLAB编程软件实现了心电信号R波检测,采用非参数直接法心电信号R波进行双谱估计,并将实验运行结果作以比较。实验结果表明高阶统计量是一种十分有效的信号检测和系统分析方法。     

Noninvasive fetal ECG estimation using adaptive comb filter

This paper describes a robust and simple algorithm for fetal electrocardiogram (FECG) estimation from abdominal signal using adaptive comb filter (ACF). The ACF can adjust itself to the temporal variations in fundamental frequency, which makes it qualified for the estimation of quasi-periodic component from physiologic signal, such as ECG. The validity and performance of the described method are confirmed through experiments on real fetal ECG data. A comparison with the well-known independent component analysis (ICA) method has also been presented.     

心电图信号采集与存储系统的设计

采用低功耗AVR单片机、点阵液晶、存储记录卡以及实时时钟芯片等器件设计了心电图信号采集与存储系统，对心电图信号采集与存储系统从重量、体积、功耗以及功能等方面进行改善，方便使用、对心电图信号采集与存储系统的工作原理、工作流程以及抗干扰等问题进行了分析。     

基于体震信号的心率检测装置的设计与实现

设计并实现了一种基于体震信号的心率检测装置。心脏泵血所引起的人体和与其接触物体的震动,经过压力传感器转换为电信号,通过放大模块等信号处理电路,再由串行接口输出到PC机中进行预处理,最后,利用一种改进的心率检测算法得到心率。同步采集一路心电信号作为时间基准测量心率,并检验装置的准确性,实验结果表明:两者测得的心率基本相同。     

心电检测技术及其在远程医疗中的应用

心血管疾病是威胁人类生命的主要疾病之一,心电图(ECG)则是评价心脏功能的主要依据,关于心电信号检测技术的研究一直为各方所关注。综述了ECG的基础理论、检测技术及其在远程医疗中的应用,并对心电信号检测技术的发展趋势作了展望。     

一种基于手机通信的心电图机设计

主要介绍了一种基于心电图采样模块与智能手机的心电图服务系统设计方法.首先给出了系统的基本框架,然后重点给出了具有蓝牙接口的心电图机设计方案以及手机终端软件设计方法,其中采用专用的心电图模块AIKD812-256与蓝牙模块HC-06设计心电图机,采用J2ME平台编程实现蓝牙通信、心电数据存储、心电数据发送至服务器的功能,并对实现过程中的关键代码进行分析,最后给出了心电图机运行的测试结果.测试结果表明本文设计的心电图机可用于远程医疗监护.     

Detection of T-wave Alternans in ECG Signals Using FRFT and Tensor Decomposition

T-wave alternans(TWA) refers to the periodic beat-to-beat variation in the amplitude of T-wave in the electrocardiogram(ECG) signal in an ABAB-pattern. TWA has been proven to be a very important indicator of malignant arrhythmia risk stratification. A new method to detect TWA by combining fractional Fourier transform(FRFT) and tensor decomposition is proposed.First, the T-wave vector is extracted from the ECG of each heartbeat, and its FRFT amplitudes at multiple orders are arranged to form a T-wave matrix. Then, a third-order tensor is composed of Twave matrices of several consecutive heart beats. After tensor decomposition, projection matrices are obtained in three dimensions. The complexity of the projection matrix is measured by Shannon entropy to obtain feature vector to detect the presence of TWA. Results show that the sensitivity,specificity, and accuracy of the algorithm on the MIT-BIH database are 91.16%, 94.25%, and92.68%, respectively. This method effectively utilizes the fractional domain information of ECG,and shows the promising potential of the FRFT in ECG signal processing.