基于智能视觉的人体跌倒检测仿真

针对传统人体跌倒检测方法准确度低,不能在人体疑似跌倒的第一时间及时检测的问题,提出基于智能视觉的人体跌倒检测方法。根据智能视觉分析技术解析人体跌倒行为,采用加速度传感器采集人体跌倒惯性特征数据并利用加速度传感器建立三轴加速坐标,对跌倒行为作出判断。在巨大的特征量集合中,运用K-L变换方法提取出准确的加速度峰值和倾角变化值,据此设置跌倒行为检测的约束条件,完成对跌倒行为的分类。采用PSO分类器优化人体跌倒检测的SVM参数,完成人体跌倒高精准度检测。实验结果表明,所提方法的检测准确度高于对比的3种文献方法,检测时间最短,能够及时检测目标个体跌倒情况,可广泛应用于现实生活中。     

基于人体姿态的P SO-SVM特征向量跌倒检测方法

在可穿戴设备检测人体跌倒情况时,单一采用加速度阈值判别方法不能完整表征人体跌倒行为变化的信息,导致对跌倒信息误判.为此,提出了一种基于人体姿态的PSO-SVM特征向量跌倒检测算法.首先通过MEMS加速度传感器节点采集人体姿态数据,并利用共轭梯度法对采集的数据进行优化处理,降低非线性误差;然后,利用支持向量机SVM(Support Vector Machine)分类器检测跌倒行为,并通过粒子群PSO(Particle Swarm Optimization)算法对SVM参数进行优化,获得最佳分类模型,根据SVM分类模型对采集的姿态数据进行分析,判断是否跌倒;最后根据人体姿态角,构建融合人体姿态角的PSO-SVM特征向量,检测跌倒过程的具体信息.实验结果表明:该检测方法取得95.5%的识别率,能够较好地区分其他非跌倒性动作,检测精度较其他方法较高,均方根误差较小,有较好的鲁棒性.     

基于智能手机的实时跌倒检测系统研究

为减少跌倒对老年人造成的伤害,并对跌倒进行实时检测,提出了一种基于Android智能手机的人体跌倒检测系统,手机安置于腰上采集手机加速度传感器数据,利用了姿态识别和跌倒检测相结合的算法,区分出跌倒行为和人体日正常常活动。当检测到异常跌倒时,报警信息以及从手机中GPS获取的位置被发送。仿真及实验表明:系统能够有效地识别出跌倒和日常行为,算法具有较高实时性、具有较高灵敏度和特异度。     

一种基于加速度传感器的人体跌倒识别方法

为了减少老年人因跌倒而造成的伤害,及时有效地识别跌倒行为,提出了一种基于三轴加速度传感器的人体跌倒识别方法。首先将加速度传感器放置于人体腰腹位置,采集人在运动时的加速度变化数据;然后使用日常活动数据训练隐马尔科夫模型(HMM),利用老年人活动状态相对较少的特点,从测量数据与HMM的匹配程度寻找"疑似"跌倒行为;最后计算短暂时间内的身体倾角,检测人体躺卧姿态,完成跌倒识别。利用HMM和身体倾角识别跌倒,解决了生活中缺乏跌倒数据训练样本的问题,提高了某些近似行为的区分度。仿真结果表明,该方法在有效识别跌倒行为的同时,提高了正确率。     

基于加速度传感器的人体跌倒检测方法

针对人体跌倒检测阈值算法在由于阈值设定不当而引起的检测精度下降问题,采用支持向量机方法决定跌倒检测的阈值大小。从加速度传感器中获取人体运动信号,提取合加速度以及倾角作为分类特征,根据人体在跌倒时经过的失重、撞击地面和平稳三个阶段,建立基于阈值的跌倒检测模型。采用所建立的跌倒检测模型,分别用支持向量机方法以及人工方法设定阈值,仿真结果显示采用支持向量机设定阈值的检测效果优于对比算法,结果表明本文方法能有效识别跌倒。     

基于Android平台的老人跌倒检测算法及APP设计

本文利用Android智能手机内置的加速度传感器和陀螺仪感器收集的运动参数,提出了基于加速度特征量、角速度特征量和角速度相似度特征量的跌倒检测算法并进行了APP设计与实现。实验结果表明,该算法能有效的检测到跌倒事件的发生,同时在人体发生跌倒倒后能及时发出定位信息及报警信息,使得跌倒人能及时准确得到救助。     

机器学习辅助IMU人体跌倒状态识别

针对单一传感器在人体运动状态监测中误差较大的问题,本文采用了高精度的陀螺加速度计 MPU6050模块.该模块使用陀螺仪输出的人体运动信息对加速度传感器采集到的姿态角信息进行修正,提高测量精度.采用机器学习的方法对样本数据进行分析,获得分类阈值.当人体由静止到跑步或由站立到坐下等状态转移时,加速度也会突然增大,有可能达到跌倒时的阈值.当采集的加速度信息的特征值大于阈值时,通过分析其产生峰值时的加速度值和该时刻及之后的角度变化,来确定是否发生跌倒事件.     

基于阈值分析法的人体跌倒检测系统

为了在老年人跌倒时及时发现并进行救助,设计了一个跌倒检测、定位报警求救的智能系统。系统使用STM32F103ZET6作为微处理器,采用ADXL345三轴加速度传感器采集数据,并用ATK—NEO—6M实现全球定位,跌倒发生时,SIM900A发送包含位置信息的求救短信给特定人员。提出了一种跌倒检测算法,根据设定的合加速度阈值和时间阈值,来检测失重、撞击、静止三个过程是否顺序发生,根据设定的姿态角阈值,检测人体姿态角是否超过正常范围,从而判断是否跌倒。测试结果表明:系统性能稳定,检测跌倒的准确率达到97%,满足人体跌倒检测的标准。     

基于三轴加速度传感器的人体跌倒检测系统设计与实现

为了满足老年人的护理需求,减少老年人因跌倒造成的身心伤害,提出了一种基于三轴加速度传感器的人体跌倒检测系统。该系统主要基于姿态测量特性,利用姿态角作为跌倒判断标准;并且考虑到噪声影响和跌倒检测系统对检测正确率的高要求,利用Kalman滤波算法来提高算法精确度。实验结果表明该系统在人体前后、侧向跌倒和跌倒后迅速站起的情况下可以100%报警,达到人体正常跌倒情况的检测标准。     

改进混合高斯模型在人体跌倒检测中的应用

提出了一种基于改进混合高斯模型的分级特征检测算法,对人体跌倒状态进行检测。针对实际目标检测过程中背景更新缓慢,阴影干扰等缺点,通过改进混合高斯模型进行背景更新,并根据阴影区域在HSV颜色空间的特征信息消除阴影干扰。利用人体最小面积外接矩形和垂直外接矩形对检测到的人体目标进行标记,分析目标区域的矩形宽高比、人体质心高度比和人体躯干倾斜角的特征变化。根据各个特征对人体不同状态的判断灵敏度,提出了一种分级特征检测的方法。首先通过人体躯干倾角的特征,判断出人处于非站立状态。接下来依次采用人体质心高度比和矩形宽高比的特征,确认人体处于跌倒状态。实验结果证明,采用提出的方法对人体跌倒状态进行检测,其环境适应性和跌倒检测准确率均高于采用背景差分和直接检测的各种方法。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate