首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
为了解决基于接收信号强度指示(RSSI)的室内定位方法定位精度低和稳定性差等问题,提出了一种基于信道状态信息(CSI)的无源室内定位算法。该算法使用卡尔曼滤波处理原始CSI信号,结合高斯径向基核函数加权的K邻近算法(RBF-KNN)与置信度空间进行室内定位。实验结果表明:该方法精度高于其他算法。  相似文献   

2.
基于信道状态信息(CSI)的定位技术在室内场景应用中被广泛关注,为了提高WiFi信号多径效应对接收信号强度指示的室内定位精度和稳定性,提出一种基于CSI信号的被动式室内指纹定位算法。该算法在离线阶段将定位场所划分为同等大小的区域块,在各连接点位置使用方差补偿的自适应卡尔曼滤波(Kalman)算法对原始数据进行滤波。再对滤波后的数据使用二分K均值聚类(K-means)算法进行分类,将处理得到的CSI幅值和相位信息共同作为指纹;在线阶段根据待测点采集的实时数据与指纹库进行匹配识别,被定位对象无需携带任何设备。仿真实验与实地实验表明,该算法利用信道状态信息中的子载波特征进行定位,能够有效减轻信号接收端的多径衰减影响,定位精度有明显提高。   相似文献   

3.
多径效应导致基于接收信号强度指示(RSSI)的室内定位精度不高,采用高细粒度的物理层信道状态信息(CSI)可以更好地描述室内多径环境,提高基于指纹的室内定位的精度。利用聚类算法提取CSI,提高了不同位置之间指纹的区分性。在定位阶段采用一种简单有效的方法进行类的匹配。实验结果表明,在使用单个信标的情况下,定位精度较以往算法提高了24%。  相似文献   

4.
无线信号的多径效应和时变性使基于接收信号强度指示(RSSI)的测量值波动较大,导致基于RSSI位置指纹的WLAN认证及攻击定位存在较大的误差。为此,提出信道状态信息(CSI)位置指纹的入网认证及攻击检测定位方案。通过正交频分复用技术获取细粒度CSI以描述位置信号特征,采用K-means优化初始聚类点算法处理数据,增强各位置信息间的差异性。在此基础上,构建基于CSI的位置地图,利用CSI位置指纹认证访问WLAN的用户身份,从而对认证失败的用户进行攻击检测和定位。在IEEE 802.11n通信标准测试中的结果表明,该方案的定位正确率高达98.12%。  相似文献   

5.
针对基于接收信号强度指示(RSSI)的定位算法中根据RSSI测距误差较大的问题,提出了在锚节点上使用天线分集技术的方法。该方法在锚节点上安装2根天线,天线互成90°,采用空间分集。锚节点在接收未知节点广播信号时,选择2根天线中信号强的天线接收信号,并记录RSSI值。实验证明:在锚节点上引入天线分集技术,可以降低无线信号多径衰落的影响,提高RSSI值的稳定性,减小了测距误差,提高了定位精度。  相似文献   

6.
李耀辉  陈兵 《计算机科学》2017,44(12):68-71
随着基于位置的服务的流行,室内定位系统也受到越来越多的关注。基于WiFi的室内定位因其开放访问和低成本的属性而吸引了大量研究人员的目光。通过采用细粒度的信道状态信息CSI代替粗粒度的接收信号强度RSSI可以减少室内多径效应的影响。采用一种与传播模型参数无关的定位方法——PILM来对接入点进行空间定位。通过有效CSI值与距离关系模型的公式变换,将问题转换为求满足最小向量二范数条件的点的坐标,即用最小二乘方法求解。通过在两种典型室内环境的实验验证了系统性能。  相似文献   

7.
为研究室内定位技术在复杂环境中的应用,以楼梯和实验室为实验场景,提出了一种基于信道状态信息(CSI)与SVM回归的室内定位方法。该方法通过基于密度的空间聚类方法(DBSCAN)去除信号噪声,并用主成分分析法(PCA)提取贡献最大的指纹特征,同时降低CSI指纹的维度。通过SVM回归建立CSI指纹与目标位置之间的非线性关系,从而达到根据测得的CSI指纹估计目标位置的目的。实验结果表明,在多径效应较强的楼梯复杂环境中,该定位系统可以在90%以上的概率下达到1 m的定位精度,实验室环境中可以在82%的概率下达到0.8 m的定位精度, 这表明基于CSI与SVM回归的室内定位方法具有高效性和可行性。  相似文献   

8.
一种基于RSSI的贝叶斯室内定位算法   总被引:2,自引:0,他引:2       下载免费PDF全文
彭玉旭  杨艳红 《计算机工程》2012,38(10):237-240
为提高室内定位系统中基于接收信号强度指示(RSSI)的定位精度,提出一种基于RSSI的贝叶斯室内定位算法。在对RSSI信号进行高斯滤波预处理后,利用三角形质心算法计算未知节点的初始坐标,对该初始坐标进行贝叶斯滤波处理,得到更加准确的坐标。实验结果表明,该算法能降低定位误差,定位精度可达98%。  相似文献   

9.
室内精确定位具有重要的应用价值.由于GPS等系统在室内受到多种因素影响无法提供精确定位,如何精确定位室内环境位置成为研究和应用的热点.通过分析无线设备的信道状态信息(CSI)可以实现无需携带设备的精准室内定位方法,并应用于多种情形下的位置追踪和感知.为了解决无线信号多径效应和噪声干扰对室内精确定位的影响,提出了基于稀疏表示的CSI室内定位方法.利用CSI提供的频率分集和多天线提供的空间分集,有效地减轻了多径效应的影响.在此基础上,通过稀疏表示方法进行了一定程度上的指纹噪声消除,提高了算法的鲁棒性和抗噪能力;利用CSI灵敏的相位特征提高了定位准确度.采用路由器作为信号发射器,利用Linux 802.11n CSI-TOOL采集CSI信号,定制清华同方台式电脑和Intel 5300无线网卡驱动搭建实验环境.实验结果表明,该算法能够有效提高室内定位的准确度和精度,平均精度在0.5 m左右,准确度达到了91%.  相似文献   

10.
随着位置服务需求的增长,基于Wi-Fi接收信号的室内定位技术一直是研究热点之一.通过检测环境变化对Wi-Fi无线信道状态信息CSI的影响,从而实现对室内人员的定位具有通用性强、部署成本低等优点.针对大多系统仅使用CSI中幅度信息所带来准确性和稳定性不足的问题,设计并实现了一种基于CSI相位信息优化的定位算法,该方法通过采集幅度和相位参数相结合作为位置指纹特征,并对特征数据进行预先平滑去噪后进行指纹库的构建,然后通过机器学习方法进行人员位置的分类识别.由于相位和幅度信息可以相互补充,弥补了某些易混淆位置的分类错误,从而解决了采用单一特征的定位准确性和稳定性问题.实验进行了两种不同多径场景下的实验,比较了不同指纹特征选取、数据预处理方法以及三种机器学习算法对定位准确度的影响,其结果表明采用本文所提出算法总体上可以在仅使用CSI幅度特征的基础上提高13%.  相似文献   

11.
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.  相似文献   

12.
European Community policy and the market   总被引:1,自引:0,他引:1  
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.  相似文献   

13.
融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。  相似文献   

14.
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.  相似文献   

15.
This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.  相似文献   

16.
Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  相似文献   

17.
《计算机科学》2007,34(4):148-148
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.  相似文献   

18.
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.  相似文献   

19.
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.  相似文献   

20.
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号