基于异步分布式检测的协作频谱感知研究

构建了一种基于异步分布式检测的协作频谱感知(CSS)模型,推导了此模型在贝叶斯准则下的最优融合方案,并提出了一种不需要主用户先验信息的次优方案——最大后验概率(MAP)检测-K/N规则融合方案.分别对采用这两种方案时,协作频谱检测的虚警概率和检测(漏检)概率性能进行了理论分析和仿真,仿真结果显示两种方案都能有效提高频谱...     

分布式无源检测系统中自适应检测融合

针对在分布式多基地雷达无源检测系统中,检测概率通常未知或时变的信息不完全的检测融合问题,研究了一种在线自适应检测融合算法,该算法基于Neyman-Pearson准则,通过局部判决估计未知的每个接收站的检测概率,从而实现最优判决融合.计算机仿真结果说明了其有效性.     

基于的贝叶斯理论的多系统定位融合算法

针对传统多系统融合定位中协作性较差,自适应性不足的问题。为了多系统定位达到更好的效果,提高多系统协同定位算法中信息融合的高效性、场景间切换的适应性,本文对传统的多系统定位融合算法进行了改进。该算法采用贝叶斯理论,多系统观测数据融合输入,建立贝叶斯概率观测模型,对多系统间定位信息直接交互,通过扩展卡尔曼滤波理论估计定位信息。在此基础上,利用各系统滤波新息和方差对场景间切换时系统概率进行实时更新,将估计结果以系统概率加权方式融合输出;仿真结果表明,在相同观测条件下,本算法与传统定位算法相比,具有更好的稳定性及自适应性。     

基于贝叶斯理论的多系统定位融合算法

针对传统多系统融合定位中协作性较差,自适应性不足的问题,为多系统定位达到更好的效果,提高多系统协同定位算法中信息融合的高效性、场景间切换的适应性,对传统的多系统定位融合算法进行了改进。采用贝叶斯理论,多系统观测数据融合输入,建立贝叶斯概率观测模型,对多系统间定位信息直接交互,通过扩展卡尔曼滤波理论估计定位信息。在此基础上,利用各系统滤波新息和方差对场景间切换时系统概率进行实时更新,将估计结果以系统概率加权方式融合输出。仿真结果表明,在相同观测条件下,改进算法与传统定位算法相比,具有更好的稳定性及自适应性。     

广义证据理论的基本框架

针对经典证据理论不能有效处理辨识框架不完整情况下的信息融合问题,提出了一种广义证据理论.新理论定义了广义基本概率指派函数,对空集的广义基本概率指派大小表明了支持辨识框架不完整命题的程度,提出了能够融合广义基本概率指派的广义组合规则,该组合规则是一个与空集基本概率指派相关的函数,同时满足交换律和结合律.广义证据理论是经典证据理论的推广,当空集赋值为零时,广义证据理论退化为经典的证据理论.用算例表明了所提出的广义证据理论的有效性.     

衰落信道WSN网络基于投票机制的决策融合

针对衰落信道网络中传感节点难以准确获取检测信息的问题,构建了并行结构分布检测的系统模型,提出了一种基于投票机制的决策融合算法。通过邻居节点间的信息交互,各传感节点获取了通讯半径内邻居节点的判决,并根据多票优先的原则重新调整自身决策,提高了检测的准确性。理论分析和仿真实验表明,该算法比传统的EGC融合规则具有更高的检测概率和稳定性,适合中等规模无线传感器网络。     

基于可信度的节点选择算法

为了解决提高检测概率与减少网络开销间的矛盾,基于数据优化融合理论,提出了基于可信度的能量融合协同感知算法（EFCS算法）及节点选择算法。通过自适应迭代算法估计出各认知用户的感知可信度,并推导出了算法检测性能与协同用户数及感知可信度间的确定关系。算法能够在达到检测性能指标的前提下,尽可能多地删除冗余协同感知用户。仿真证明,节点选择算法在保证较高的检测概率的同时极大的节省了网络开销。     

基于信息融合技术的电网故障诊断方法

利用采样数据间的相互关系,以电网元件相关先验概率为基础,通过D-S(Dempster-Shafer)证据理论对检测的故障信息进行融合,获取缺失数据发生的概率;同时,将概率的概念引入Petri网建模,将获取的状态概率值代人概率Petri网故障诊断模型进行故障的诊断,以解决电网故障诊断过程中的信息不完备问题.实例证明,该方法可扩充电网故障的诊断范围.保障电力系统安全运行.     

基于多传感器信息融合理论的交互式多模型算法

在经典的交互式多模型算法中,对似然函数的高斯近似以及概率密度函数与概率质量函数的混合计算使得所求得的模型概率仅为贝叶斯意义下的次优值.为解决此问题,基于各滤波器估计误差的相关性和多传感器最优信息融合准则,提出了一种重新加权的交互式多模型算法.该算法通过计算估计误差的互协方差阵对模型概率进行更新,在此基础上利用最优信息融合理论对各滤波器的滤波结果进行融合.理论分析及仿真结果表明:经过重新加权的交互式多模型算法较原始算法以及其他忽略误差相关性的交互式多模型的改进算法在估计精度上均有显著的提高.     

认知无线电空闲频谱的联合检测算法

为了提高认知无线电中感知用户对主用户(弱信号)的检测性能,提出了一种多个感知用户合作的分布式优化联合检测算法.该算法在知道主用户信号和噪声的概率分布的条件下,通过最优化理论中的逐步二次规划法,联合求解检测系统的最优融合准则和各感知用户的最优判决门限,使系统联合检测概率取极大值.该算法不受接收机检测方式的限制,数值求解收敛速度快.仿真结果表明,感知用户为5个、融合中心虚警概率为0.1、相关符号累积为255次、不同融合准则下各感知用户信噪比相同时,与最好的固定融合准则检测算法相比,该算法使联合检测概率在高斯白噪声信道和平坦瑞利衰落信道中分别提高了13%和5%.     

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-