RSSI和PC-CSI加权融合的指纹定位方法

针对基于RSSI和CSI的指纹定位技术易受环境干扰、定位精度较低的问题,提出了一种基于RSSI指纹和相位修正信道状态信息(phase correct based channel state information, PC-CSI)指纹的加权融合指纹定位技术。基于PC-CSI的指纹定位在传统基于CSI幅值的指纹定位基础上增加相位信息对定位结果进行修正,之后对RSSI指纹和PC-CSI指纹的定位结果加权重定位。实验结果表明,提出的加权融合指纹定位算法与基于CSI的主动定位算法相比,平均定位误差(mean position error,MPE)降低了36.2%,能满足室内定位需求。     

一种利用信道状态信息的室内指纹定位方法

传统的室内指纹定位技术通常是利用接收信号强度指示(RSSI)来生成指纹,然而由于RSSI易受到环境变化等因素的影响,无法进一步提高定位精度。本文提出了一种利用信道状态信息(CSI)的指纹定位方法。充分利用多入多出(MIMO)和正交频分复用(OFDM)技术的频率分集和空间分集的优势,以接收天线为单位对信号进行聚合,将处理后CSI子载波的幅度和相位信息作为位置指纹。在会议室和实验室测试了影响定位精度因素,并分别与1种基于RSSI的指纹定位方法和2种基于CSI的指纹定位方法进行了对比分析。实验结果表明:本文提出的定位方法在会议室和实验室中的定位误差分别是0. 85 m和1. 28 m,定位精度优于其他3种方法。     

基于聚类的PCA和GRNN的CSI指纹定位算法

针对多径效应影响指纹定位算法中定位精度的问题,提出了一种基于聚类的主成分分析(principal compo-nent analysis,PCA)和广义回归神经网络(generalized regression neural network,GRNN)的信道状态信息(channel state information,CSI)指纹定位算法.离线训练阶段,利用中值滤波对CSI幅值进行去噪,并利用线性变换校准CSI相位,将处理后的幅值和相位作为原始联合指纹,利用改进的K-means算法将各个参考点的联合指纹集划分成多个子数据集来描述位置的多径特性,通过高维数据的PCA算法提取子数据集的特征以减少冗余信息、提高不同位置指纹的区分性,最后利用特征指纹训练GRNN模型.在线阶段,利用训练好的GRNN模型对在线测量的CSI数据进行目标对象的位置预测.实验结果表明,该算法可有效反映出位置的多径信息,且与CSI-MIMO,DeepFi和CSI-PCA相比,在定位精度方面有明显的提升.     

基于RBF神经网络的弧焊机器人轨迹跟踪控制方法

针对目前弧焊机器人的控制算法大多是基于关节空间的算法,而这种算法无法实现对机械臂末端位置的直接控制的问题,提出了基于笛卡尔空间的轨迹跟踪控制算法.首先运用RBF(radical basis function)神经网络技术对实际机械臂数学模型的建模误差和参数不确定性进行补偿,接着定义Lyapunov函数并运用HJI(Hamilton-Jacobi inequality)定理设计基于笛卡尔空间的机器人鲁棒控制器.在此基础上以二自由度机械臂为被控对象进行仿真研究,仿真结果表明,基于笛卡尔空间算法的轨迹跟踪控制算法误差小于基于关节空间的控制算法,在基于笛卡尔空间的控制算法的仿真中末端轨迹跟踪误差小于0.08 mm,神经网络能够有效地在线学习机器人的建模误差和参数不确定性.     

基于群智感知和非监督式学习的室内定位指纹库构建算法

针对指纹法定位中的指纹库构建耗费大量人力和时间的问题,提出了一种基于群智感知和非监督式学习的室内定位指纹库构建算法.首先利用群智感知的方式采集无线接入点的接收信号强度获取原始指纹数据集.然后针对原始指纹数据的冗余杂乱和指纹注释问题,提出基于学习向量量化(LVQ)和多维标度(MDS)结合的一种新颖算法FLM来解决.最终有效构建室内定位指纹库.最后基于射线跟踪模型(ray-tracing)建立仿真实验场景,仿真结果表明其指纹库建立效率得到显著提高,应用于基本定位算法的定位误差80%,在2.6,m以下,而且单次定位的计算量下降63%,.     

一种基于轨迹指纹优化的室内定位算法

针对指纹数据质量大幅下降的问题,提出了一种基于轨迹指纹建模的新型数据结构来替换原有的单点指纹,在兼容现有指纹定位框架的前提下,对传统离线指纹库进行了轨迹指纹库建模,同时也对在线采集的实时指纹进行了轨迹指纹映射。实验结果表明基于轨迹指纹优化的定位算法能够将室内指纹定位精度提高近一倍,定位性能明显优于其他单点室内指纹定位算法。     

基于无迹卡尔曼滤波的无人机跟踪算法

基于四基站对无人机位置的定位数据,利用无迹卡尔曼滤波算法对定位数据进行最优估计,并预测无人机的运行轨迹,从而实现对无人机的实时跟踪.对经典的线性卡尔曼滤波算法和无迹卡尔曼滤波算法进行仿真对比,结果表明,线性卡尔曼滤波算法虽然能跟踪预测轨迹,但有较大的误差,而使用无迹卡尔曼滤波算法能有效地减小误差,使跟踪预测的轨迹更加精确.     

基于相似指纹特征的室内定位机制研究

针对指纹定位结果中存在较大定位误差问题,分析了离线相似指纹对应采集点的分布特征,发现存在部分相似指纹对应的采集点位置距离较远的特征,这导致了较大定位误差的出现。据此提出了一种基于阈值的Dynamic-kNN的算法来实现指纹的匹配,并进一步针对相似指纹的聚类特征设计了基于K-Means的聚类优化算法,从而大大减少了定位结果中较大误差的存在。实验表明,该算法能够将最大定位误差缩小到5m以内,同时4m以上的较大定位误差所占比例也明显下降。本研究与其他算法相比,在定位性能和算法开销上具有明显优势。     

位置指纹算法关键参数的提取

针对传统的位置指纹定位算法在室内定位中存在着接收信号强度值不稳定以及不同终端设备获取AP信号强度能力不一样的问题,对传统的位置指纹定位算法进行了改进.对离线阶段采集到的RSSI值进行处理,去除了较大误差的样本,利用RSSI信号强度差值取代RSSI值作为信号特征录入Radio Map,减小了由于设备差异而产生的指纹信息误差.测试阶段,在Android和PC平台上进行验证,实验结果表明,改进的算法可以有效地去除离线阶段误差较大的样本并提高了该算法针对不同终端应用的能力.     

一种机器人系统的鲁棒轨迹跟踪方法

文章基于标称模型，在反馈力矩补偿控制的基础上，考虑在实际机器人系统存在不确定性(外部扰动及摩擦力)时，基于终值有界定理，运用连续状态反馈的方法设计出一个新的机器人轨迹跟踪控制器．数值仿真表明，在初始误差较大的情况下，该轨迹跟踪控制器能够保证跟踪误差的终值有界性。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.