六自由度电磁跟踪系统远场模型的修正

为了扩大六自由度电磁跟踪系统的应用范围,实现远距离精确跟踪定位,对系统原近场定位模型进行修正,在磁偶极子远场表达式的基础上,建立电磁跟踪系统的远场修正模型。在远场修正模型基础上,采用基于最大单位指向矢分量的跟踪算法计算目标的位置参数(R,α,β)。为了解决位置变换矩阵不可逆的问题,引入四元数法求解系统的姿态变换矩阵,进而结合跟踪算法求解姿态参数(ψ,θ,φ)。数值模拟结果表明了该修正模型能够显著提高系统远距离跟踪定位的精度,参数求解算法快速准确。     

一种基于隐马尔可夫模型的目标轨迹跟踪算法

现有的定位算法只表现了目标的静态位置特征, 不能较好地在目标移动情况下跟踪获取目标的运行行为轨迹。针对这一问题, 设计了一种基于隐马尔可夫模型的目标轨迹跟踪算法。该算法根据小区覆盖范围内的地理位置信息和目标用户的移动速度, 建立隐马尔可夫模型; 然后, 基于维特比译码算法对最佳路径和最佳状态概率进行最优化求解, 实现对目标轨迹的跟踪。仿真结果表明, 该算法可以在基站小区分辨率下精确地获取目标轨迹。     

一种简化的室内机器人电磁定位算法与系统

文章提出了一种简化的室内机器人的电磁定位算法。在定位空间内布置一个发射线圈和一个三轴接收线圈,形成电磁耦合系统。以接收线圈三轴为参考建立空间直角坐标系,并对发射线圈加载正弦电信号作为激励信号,产生交变电磁场。接收线圈感应到磁场的变化,通过测量计算感应耦合的强度特征值,确定移动目标的位置参数。本系统将三轴接收线圈固定,而将水平发射线圈置于平面移动机器人目标之上,这样可将定位算法简化。根据磁偶极子模型,提出了解析计算方法。通过仿真和实验,证明该方法能够满足室内机器人的定位要求,是可行且有效的。     

面向机器人运动跟踪的电磁定位系统

电磁定位具有精度高、速度快和易实现等优点,所以对手术、室内和室外机器人跟踪是一个良好的选择。电磁定位以交变电磁信号作为源信号。交变的电流信号激励发射线圈（信号激励部件）在空间中产生交变的电磁场,感应线圈（信号感应部件）在交变的电磁场中输出频率相同的信号。根据输出信号的幅值和相位信息,我们可以计算出感应线圈相对于发射线圈的位置和方向信息。本文面向机器人定位跟踪,介绍电磁定位系统的原理与实现,包括磁场模型、电磁定位算法与系统软硬件的搭建与实验。本文介绍两种不同的激励模式,分别为分时激励3轴正交发射线圈模式与同时激励2轴正交发射线圈模式,两种模式中的感应线圈均采用3轴正交线圈。实验结果表明,定位系统可以达到1 mm的定位精度。     

基于Kullback-Leibler分歧的变分滤波WSNs贝叶斯移动定位跟踪西

为了在降低资源能耗和带宽占用情况下,提高无线传感器网络WSNs移动目标定位跟踪的精度,提出了基于Kullback-Leibler分歧的变分滤波的WSNs贝叶斯移动目标定位跟踪算法。首先,利用高斯和Wishart分布在不考虑速度限制和方向移动限制情况下,构建WSNs移动定位的贝叶斯状态演化模型,并基于路径损耗模型构建移动目标定位的观测模型;其次,利用Kullback-Leibler分歧构建变分滤波的误差计算模型,通过周围激活节点实现移动节点目标的位置估计,设计了递归概率计算过程综合预测和更新两个过程,并实现了定位和目标跟踪的同步化;最后,通过仿真验证了所提模型在跟踪精度和资源节约上的优势。     

基于SRUKF的TSOA/TDOA单站跟踪技术研究

阐述了蜂窝网系统中单台定位设备TSOA/TDOA被动式新型混合定位技术的原理.利用TSOA/TDOA混合定位的数学模型建立系统观测方程,采用受随机加速影响的匀速运动状态模型,描述了移动台的位移和速度.在此基础上推导了基于平方根无迹卡尔曼滤波的跟踪算法,并通过仿真实现了对移动台位置和速度的同时跟踪.仿真结果表明,与扩展卡尔曼滤波及无迹卡尔曼滤波算法相比,平方根无迹卡尔曼滤波算法的跟踪性能更优.     

多站时差无源定位传感器网络优化

在可移动无源传感器网络中,观测器与目标的相对几何关系对定位精度有重要影响。为提高对运动目标的定位跟踪精度,提出一种基于时差无源定位几何稀释精度的移动平台实时布站方法。首先推导出二维时差无源定位方法下的带有基线长度和基线偏角的GDOP表达式,将其作为目标优化函数,使用加权离散搜索优化算法求解网内各观测器每一时刻的最佳观测位置,并在此最佳位置对目标进行量测,完成目标运动分析。该方法通估计和优化相结合实现移动平台无源传感器网络的实时优化部署,仿真证明该算法一定程度上解决了时差无源定位算法的定位模糊问题,提高了对运动目标的跟踪精度。     

多观测器轨迹优化仿真研究

研究优化机载雷达组网系统的跟踪性能问题,在机载雷达组网中,多观测器与目标间的相对几何关系对定位跟踪精度有影响.可通过改变观测载体的飞行速度和航向角,控制其沿最优轨迹运动有效提高观测器的估计性能.为了对多站时差无源定位准确跟踪问题提出遗传算法对机载多观测器轨迹进行优化.推导出目标优化函数的表达式,采用遗传的轨迹优化算法,求解每一采样时刻使得目标函数最小的观测器位置,并在最佳位置对目标进行量测.可将轨迹优化加入运动目标被动跟踪过程构成闭环,通过估计和优化相结合的方法仿真实现观测器自适应运动下的运动目标被动跟踪.通过结果比较证明,算法可以有效提高对运动目标的跟踪精度.     

基于AUPF的TDOA几何定位跟踪算法研究

使用无源时差（TDOA）定位技术确定无人机等小型辐射源目标的位置是当前研究的热点,针对时差定位算法较为复杂的实际情况,推导了时差双曲线的几何解,并提出了一种基于自适应无迹粒子滤波（AUPF）技术的移动目标定位跟踪方法。通过仿真对该方法在不同场景的应用效果进行了验证,进一步比较分析了算法的定位精度。结果表明,基于自适应无迹粒子滤波的时差几何定位跟踪算法可以在多种情况下较好地拟合出目标真实运动轨迹,实现对运动目标的定位跟踪,同时拥有更低的定位误差和更高的轨迹包容度,使用该方法可以显著提高对非合作移动辐射源目标的位置估计性能。     

基于移动节点的无线传感器网络定位算法

节点定位技术是无线传感器网络应用的重要支撑技术之一,为了提高定位算法的准确性,提出了一种基于移动目标节点的两步定位算法。该算法利用一个移动目标节点遍历整个网络,并周期性地广播包含自身当前位置的信息。而传感器节点的自身定位过程则可用基于无迹卡尔曼滤波(UKF)的目标跟踪方法实现。由于所用的目标状态模型和量测模型有一定的不确定性,所以先选取不共线的3个拥有RSSI测距能力的目标节点信息,利用Euclidean定位法提高滤波的初始位置精度,从而改善定位效果。通过仿真、分析和比较该目标节点在多种移动轨迹情况下的定位误差,这种两步定位法可以改善对目标节点移动轨迹的特殊要求的限制,能取得较好的定位精度,而且更适合于实际情况。     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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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