基于估计距离的无需测距定位算法

针对无需测距定位算法定位误差大的问题,提出了一种基于估计距离的无需测距定位算法.首先分析了两个邻居节点之间距离和通信范围相交面积之间的关系,得到一个线性函数.线性函数的输出是一个表示两个邻居节点之间距离远近关系的参数,称之为距离参数.然后用距离参数和锚节点之间的距离计算邻居节点之间的估计距离,最后根据估计距离计算未知节点的估计位置.仿真结果表明,该算法在规则区域和不规则区域的定位误差都要低于当前同类型的定位算法.     

基于分布式加权多维定标的节点自身定位算法

提出了一种基于对称K最邻近（SKNN）传感器网络节点分布式精确定位算法．该算法首先采用SKNN方法选择每个节点的邻居节点，通过接收信号强度（RSS）方法测得每对节点之间的距离，构建节点距离矩阵，并以距离矩阵为输入，应用分布式多维加权算法对矩阵进行处理，从而获得传感器网络节点之间的局部映射关系．最后，根据参考节点的坐标对节点局部映射关系进行匹配，以获取节点坐标的全局映射．仿真实验表明，采用所提算法可以加强定位精度，提高计算效率，在有25个节点的传感器网络中，定位误差要比dwMDS方法低大约5%。     

距离估计修正的定位算法优化研究

在无线传感器网络(WSNs)节点定位中,定位精度是传感器节点定位的关键因素.提出一种距离估计修正定位算法,通过节点之间的跳数加权和平均每跳距离误差修正的组合优化方法实现节点的距离估计预处理,再使用L-M算法进行节点定位计算.设定不同节点规模、锚节点比例、节点通信半径情况下的仿真分析,与IDV-Hop和TWDV-Hop算法相比较,优化算法在定位精度性能方面有较大提升.     

基于距离估计的无线传感网络移动节点定位研究

针对传统MCL算法定位精度低的不足,提出了一种基于距离估计的改进蒙特卡罗定位算法—DEMCL.首先根据网络连通度、锚节点信息和节点间的相邻关系估计目标节点与锚节点间的距离;然后利用该距离构建新的过滤条件加入算法的过滤阶段,以优化样本集和减小定位误差;最后以Matlab为工具对算法的定位性能进行仿真和分析.仿真结果表明:在同一环境下,与MCL算法和MCB算法相比,DEMCL算法能保证更高的定位精度,同时减少了无效定位的节点数目,网络覆盖率可达到98.83%.     

基于细菌觅食算法和跳段校正的无线传感器网络定位算法

对目前应用较为广泛的DV-Hop 定位算法进行了分析,针对其在跳段估计及位置计算中的不足,提出了一种基于细菌觅食算法（BFA）和跳段校正的定位算法BFA-HC.该算法首先根据接收信号强度指示（RSSI）阈值优化节点间的跳数,在此基础上基于最小均方误差准则计算锚节点的平均每跳距离,当未知节点获得3 个或以上锚节点的距离后应用细菌觅食算法进行位置估计.仿真结果显示,BFA-HC 算法在不同网络规模、不同网络连通度及不同锚节点比例条件下均可以显著提高传感器网络节点的定位精度.     

基于测距的地面网络化弹药节点自定位算法

分析了极大似然估计算法中测距误差对定位误差的影响,提出了基于LMS（最小均方差）的自适应滤波原理的测距误差修正的自定位算法. 利用极大似然估计法初步估计节点位置,并得到定位误差信息,建立测距误差矩阵并更新网络中的滤波参数,完成对网络中测距误差的抑制,从而优化节点定信息. 实验仿真表明,优化处理使定位精度得到提高. 结果表明算法适用于锚节点密度较小的、低信噪比的网络化弹药系统.     

一种基于Quasi-UDG模型的无线传感器网络非测距定位算法

针对Quasi-UDG模型下无线传感器网络随机部署的拓扑特征,提出了一种非测距基于权重的定位算法EWLS(Enhanced Weighted Least Square).首先,设计出一种节点跳数和距离关系估计的方法,然后依据跳数值与距离关系的概率表达式,给出EWLS定位算法中节点测量距离信息的权重.仿真实验表明,在不同的锚节点密度、Quasi-UDG模型因子和平均邻居节点数的参数下,EWLS算法定位误差较小,同最小均方误差相比,有效地提高了节点定位的精度.     

基于接收信号强度指示加权融合的定位算法

基于接收信号强度指示的无线传感器网络定位问题,提出一种改进Kalman滤波方法,消除测距过程中的非视距误差,得到标签与节点间的估计距离.然后,分析标签与节点的距离、定位单元质量和标签所处的位置三方面对定位精度的影响,提出一种改进三边定位算法,并根据滤波后的估计距离计算得到的多个定位坐标进行加权融合.最后,通过Matlab仿真验证所提算法的有效性.     

基于高斯混合模型的无线传感器网络定位算法

针对距离误差对定位结果的影响, 提出一种基于高斯混合模型的无线传感器网络定位算法. 该算法将高斯混合模型方法引入到无线传感器网络的定位问题中, 通过高斯混合模型分析找出误差较大的距离信息并将其剔除, 对剩余距离信息使用三边测量定位法进行定位求解, 同时结合加权定位算法进行位置估计. 仿真实验结果表明, 改进算法能提高定位精度, 且定位结果更稳定.     

改进的无线传感器网络无偏距离估计与节点定位算法

针对无线传感器网络中基于跳数的节点定位算法不能满足无偏距离估计、节点定位误差大的问题,提出了一种改进的无偏距离估计与节点定位算法(UEDV-hop,Unbiased Estimation DV-hop)。该算法分析期望距离和跳数的关系,建立一种新的期望距离与跳数模型,根据节点通信半径是否已知分别推导了两种UEDV-hop的求解形式。仿真实验结果表明:所提的两种UEDV-hop算法的估计距离在不同跳数时都近似等于该跳期望距离,算法在距离估计和节点定位精度上相对于DVhop(Distance Vector-hop)算法及基于最小二乘法改进的DV-hop算法都有较大提高,在节点数目等于2 500时,UEDV-hop算法的估计距离误差比DV-hop算法降低了9.5%,定位精度提高了55%。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

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

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-