面向整体区域的改进VIRE定位算法研究

VIRE定位算法的虚拟参考标签分布在中心区域,导致非中心区域定位精度低,并且算法需要根据环境重复调整阈值,增加了实验难度。针对上述问题,在VIRE算法的基础上提出面向整体区域的改进VIRE算法。首先,将虚拟参考标签放置到整体定位区域;同时,利用牛顿插值估算虚拟参考标签的RSSI值;随后,通过动态阈值选择邻近参考标签,经过邻近参考标签可信度检查后确定最终邻近参考标签;最后,对其进行误差校正得到定位标签的坐标。仿真实验结果表明,该改进VIRE算法不仅在定位精度上有大幅提升,而且对定位环境有较强的适应能力。     

基于非度量多维标度的室内多标签协同定位算法

与有源标签相比,无源RFID标签成本较小,本文选取后者作为待定位标签。但是由于无源RFID标签之间无法通信,目前大多数传统的RFID定位算法一次只能定位一个标签而无法实现多标签同时定位。针对这一问题,提出了基于非度量多维标度(NMDS)的室内RFID多标签协同定位算法。利用到达相位差(PDOA)法拟合在多径存在环境下的测距误差,将待定位标签之间的距离差欧氏距离与非度量多维标度算法结合,计算出待定位标签的位置坐标。仿真结果表明,提出的算法可以通过一次非度量多维标度计算得到所有待定位标签的坐标,同时定位精度高于经典多维标度定位算法和传统三边定位算法。     

邻近参考标签权值的射频识别室内定位算法

介绍了VIRE算法和BVIRE算法的定位原理。在BVIRE算法的基础上,提出了一种基于邻近参考标签的权值的改进算法(简称WBVIRE算法)。该算法通过改进最近邻参考标签与待定位标签的信号强度的差值,重新设定邻近参考标签的权值计算方法,以得到更加准确的待定位标签的坐标,从而提高 BVIRE 算法的室内定位精度。实验结果表明, WBVIRE算法明显提高了室内定位精度。     

基于克里金插值的自适应VIRE室内定位算法研究

VIRE算法在虚拟标签计算上往往采用线性插值方法计算RSSI与距离的关系,易导致误差增大,并且需要通过反复调整实验获得的标签消除阈值为固定值,增加了定位的时间复杂性,针对这两点问题提出一种基于克里金插值的自适应VIRE室内定位算法。利用克里金插值估计虚拟标签的RSSI值,并根据待定位标签的实时特点自动调整阈值,使邻近标签数量接近最优,更准确地排除干扰,从而获得定位坐标。实验对比结果表明,该算法不仅节约定位成本,而且提高了定位精度。     

基于RFID的边界虚拟参考标签改进算法

依据对室内定位算法的场景分析,在BVIRE算法的基础上,提出了一种室内定位的改进算法IMPRO_BVIRE。针对信号在无线信道中的衰减规律呈非线性,该算法采用一种非线性插值方法计算虚拟参考标签的RSSI值,在邻近参考标签的选择上采用小概率排除法,排除了小概率点对定位精度的影响,并通过取均值抵消了阴影带来信号的剧烈波动。仿真与实验结果表明,改进后的IMPRO_BVIRE算法相比于BVIRE算法具有更低的定位误差。     

基于KNN算法的可变权值室内指纹定位算法

针对基于静态权值的室内指纹定位算法存在定位精度低、定位结果不稳定以及环境适应性差等问题,提出一种以欧氏距离为权值参考的可变权值室内指纹定位算法。该算法分为离线采样阶段和在线定位阶段。离线采样阶段对接收信号强度指示(RSSI)值进行高斯滤波去噪构建指纹库。在线定位阶段引入权值指数α、β,分别以RSSI、欧氏距离为权值参考计算最近邻点及其加权质心,得出待测节点的坐标。实验结果表明,相比KNN和RW算法,该算法定位精度高,其平均误差为0.965 m,且定位误差波动小。     

基于RFID的虚拟标签算法研究与改进

针对室内定位算法VIRE的定位精度,特别是邻近边界目标的定位精度较低的问题,以RFID标签定位为研究基础,从改变VIRE算法中虚拟标签的插值方式和在边界上加入虚拟标签两个方面进行研究和改进。使用拉格朗日插值代替VIRE算法中的线性插值方式,使虚拟标签的数据更加接近实际环境值;在边界上加入虚拟参考标签能增加已知标签数,防止在计算待定位标签坐标时引入误差标签。实验结果表明,标签定位精度有了明显提高,整体能提高了35%,邻近边界标签定位精度提高较大,可达到50%以上。     

基于RFID虚拟标签的室内停车场车辆定位算法

在室内停车场中应用基于RFID的LANDMARC算法进行车辆定位时,由于室内停车场的复杂结构以及多径效应的影响,车辆定位精度不能通过增加参考标签数目或均匀规则的部署参考标签等方式来提升。提出了一种基于虚拟RFID标签的室内定位算法(location algorithm based on virtual tag, LAVT)。该算法通过近邻标签确定车辆的近邻区域,计算出近邻区域的外心并插入虚拟参考标签;通过虚拟参考标签替换原近邻标签、缩小近邻区域面积,使新近邻标签更临近待定位车辆,从而更精确地计算出车辆的位置。仿真实验表明：LAVT算法在室内停车场环境中将车辆定位精度提升了19.03%。LAVT算法应用于室内停车场环境中的车辆定位具有更好的适用性,能满足室内停车场车辆定位的基本需求。     

空间划分虚拟网格的RFID室内定位算法

首先分析了最近邻居算法的基本原理,针对把所有参考标签作为最近邻居的选择,出现大量不必要计算,室内环境干扰较大,距离阅读器较远的标签的信号强度值阅读不准确的问题,提出了一种划分虚拟网格,动态选取最近邻居来进行定位的RFID室内定位算法.仿真结果表明,在不增加参考标签的前提下,改进的算法较最近邻居算法定位精度更高,稳定性更好.     

基于RFID的边界虚拟参考标签定位算法

介绍VIRE室内定位算法的原理,针对VIRE算法对边界标签定位准确度低的问题,提出边界虚拟参考标签定位算法BVIRE。该算法通过建立线性回归方程,在边界处加入边界虚拟参考标签。仿真结果表明,在不额外增加参考标签且不增大射频干扰的前提下,BVIRE算法较原算法使靠近边界处待定位标签的定位准确度得到较大提高。     

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.     

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.     

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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