期刊文献+
共找到18篇文章
< 1 >
每页显示 20 50 100
Tracy-Widom分布及其应用 被引量:6
1
作者 苏中根 《应用概率统计》 CSCD 北大核心 2016年第6期551-580,共30页
Tracy和Widom 1990年代在研究高维随机矩阵特征根时发现一种新型分布,文献中普遍称为Tracy-Widom分布,它用于描述极值特征根的渐近性质.随后二十多年的研究表明,TracyWidom分布如同经典的正态分布那样具有普适性,适用于各种极值型随机现... Tracy和Widom 1990年代在研究高维随机矩阵特征根时发现一种新型分布,文献中普遍称为Tracy-Widom分布,它用于描述极值特征根的渐近性质.随后二十多年的研究表明,TracyWidom分布如同经典的正态分布那样具有普适性,适用于各种极值型随机现象.作为例子,本文简要描述了九种常见的随机模型,它们都以某种方式与Rracy-Widom分布有关.与正态分布相比较,TracyWidom分布的密度函数、分布函数、数字特征都显得非常复杂,为了进一步推广和应用,需要相当好的数学基础和计算能力.但是,由于该分布的重要性,无论如何值得更多的关注. 展开更多
关键词 正态分布 Gumbel分布 tracy-widom分布 普适性原理
下载PDF
基于极限特征值之差的改进频谱感知算法
2
作者 田堃 谭哲文 +2 位作者 谭宇豪 雷可君 杨喜 《吉首大学学报(自然科学版)》 CAS 2024年第2期35-39,44,共6页
基于取样协方差矩阵的最大和最小特征值之差的频谱感知算法,从提高感知判决门限的设置准确度出发,利用Wishart随机矩阵极限特征值分布的最新成果,设计出了一种新的判决门限计算方法.仿真实验结果表明,相对于现有的频谱感知算法,新算法... 基于取样协方差矩阵的最大和最小特征值之差的频谱感知算法,从提高感知判决门限的设置准确度出发,利用Wishart随机矩阵极限特征值分布的最新成果,设计出了一种新的判决门限计算方法.仿真实验结果表明,相对于现有的频谱感知算法,新算法的判决门限计算更加准确,在改善判决结果可靠性的同时,有效地提升了有限样本数量条件下算法的检测性能. 展开更多
关键词 认知无线电 频谱感知 Wishart矩阵 极限特征值 tracy-widom分布
下载PDF
Tracy-Widom distribution, Airy2 process and its sample path properties
3
作者 SU Zhong-gen LEI Yu-huan SHEN Tian 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2021年第1期128-158,共31页
Tracy-Widom distribution was rst discovered in the study of largest eigenvalues of high dimensional Gaussian unitary ensembles(GUE),and since then it has appeared in a number of apparently distinct research elds.It is... Tracy-Widom distribution was rst discovered in the study of largest eigenvalues of high dimensional Gaussian unitary ensembles(GUE),and since then it has appeared in a number of apparently distinct research elds.It is believed that Tracy-Widom distribution have a universal feature like classic normal distribution.Airy2 process is de ned through nite dimensional distributions with Tracy-Widom distribution as its marginal distributions.In this introductory survey,we will briey review some basic notions,intuitive background and fundamental properties concerning Tracy-Widom distribution and Airy2 process.For sake of reading,the paper starts with some simple and well-known facts about normal distributions,Gaussian processes and their sample path properties. 展开更多
关键词 Airy2 process Dyson Brownian motion tracy-widom distribution sample path property.
下载PDF
一种基于极值特征值之差的全盲多天线频谱感知算法
4
作者 雷可君 杨喜 +4 位作者 向长青 汪旭明 田堃 谭哲雯 夏舜晖 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2023年第12期76-85,共10页
提出了一种新的基于接收信号取样协方差矩阵(SCM)极值特征值之差的多天线频谱感知算法BDDEE,其以SCM的最大最小特征值之差与接收信号平均能量之比作为感知判决量,在检测过程中摆脱了对噪声方差的依赖,且无须使用主用户信号及无线传输信... 提出了一种新的基于接收信号取样协方差矩阵(SCM)极值特征值之差的多天线频谱感知算法BDDEE,其以SCM的最大最小特征值之差与接收信号平均能量之比作为感知判决量,在检测过程中摆脱了对噪声方差的依赖,且无须使用主用户信号及无线传输信道等相关参数.在此基础上,基于有限维Wishart随机矩阵有序特征值分布的相关结果,从理论上提出了一种精确的虚警概率和判决门限的分析和计算方法;更进一步,考虑到次级用户计算和存储资源的限制,利用高维Wishart随机矩阵中极值特征值的分布理论,通过融合最大和最小特征值极限分布所对应的判决门限,提出了一种低计算复杂度的判决门限计算方法.综合考虑检测性能和虚警性能指标来看,新算法比经典的CAV、MME和DMME算法具有更优的感知性能,在样本数目有限的条件下能获得更加稳健的检测结果,数值仿真结果证明了所提BDDEE算法的有效性. 展开更多
关键词 认知无线电 频谱感知 极值特征值 随机矩阵 tracy-widom分布
下载PDF
Research on Spatial Pattern and Its Industrial Distribution of Commercial Space in Mianyang Based on POI Data 被引量:2
5
作者 Da Zheng Changqi Li 《Journal of Data Analysis and Information Processing》 2020年第1期20-40,共21页
The rational layout of urban commercial space is conducive to optimizing the allocation of commercial resources in the urban interior space. Based on the commercial POI (Point of Interest) data in the central district... The rational layout of urban commercial space is conducive to optimizing the allocation of commercial resources in the urban interior space. Based on the commercial POI (Point of Interest) data in the central district of Mianyang, the characteristics of urban commercial spatial pattern under different scales are analyzed by using Kernel Density Estimation, Getis-Ord , Ripley’s K Function and Location Entropy method, and the spatial agglomeration characteristics of various industries in urban commerce are studied. The results show that: 1) The spatial distribution characteristics of commercial outlets in downtown Mianyang are remarkable, and show a multi-center distribution pattern. The hot area distribution of commercial outlets based on road grid unit is generally consistent with the identified commercial density center distribution. 2) The commercial grade scale structure has been formed in the central urban area as a whole, and the distribution of commercial network hot spots based on road grid unit is generally consistent with the identified commercial density center distribution. 3) From the perspective of commercial industry, the differentiation of urban commercial space “center-periphery” is obvious, and different industries show different spatial agglomeration modes. 4) The multi-scale spatial agglomeration of each industry is different, the spatial scale of location choice of comprehensive retail, household appliances and other industries is larger, and the scale of location choice of textile, clothing, culture and sports is small. 5) There are significant differences in specialized functional areas from the perspective of industry. Mature areas show multi-functional elements, multi-advantage industry agglomeration characteristics, and a small number of developing areas also show multi-advantage industry agglomeration characteristics. 展开更多
关键词 Point of INTEREST (POI) Commercial Space Aggregating FEATURE Industry dis-tribution Mianyang
下载PDF
In-Network Puncturing for Delay-Efficient Rate Control of Distributed Video Coding in Wireless Video Sensor Networks 被引量:1
6
作者 Zhang Haitao Ma Huadong 《China Communications》 SCIE CSCD 2012年第6期45-54,共10页
Wyner-Ziv Video Coding (WZVC) is considered as a promising video coding scheme for Wireless Video Sensor Networks (WVSNs) due to its high compression efficiency and error resilience functionalities, as well as its... Wyner-Ziv Video Coding (WZVC) is considered as a promising video coding scheme for Wireless Video Sensor Networks (WVSNs) due to its high compression efficiency and error resilience functionalities, as well as its low encoding complex- ity. To achieve a good Rate-Distortion (R-D) per- formance, the current WZVC paradi^prls usually a- dopt an end-to-end rate control scheme in which the decoder repeatedly requests the additional deco- ding data from the encoder for decoding Wyner-Ziv frames. Therefore, the waiting time of the additional decoding data is especially long in multihop WVSNs. In this paper, we propose a novel pro- gressive in-network rate control scheme for WZVC. The proposed in-network puncturing-based rate control scheme transfers the partial channel codes puncturing task from the encoder to the relay nodes. Then, the decoder can request the addition- al decoding data from the relay nodes instead of the encoder, and the total waiting time for deco- ding Wyner-Ziv frames is reduced consequently. Simulation results validate the proposed rate con- trol scheme. 展开更多
关键词 wireless video sensor networks dis-tributed video coding WZVC rate control delay-efficient
下载PDF
A generalized Weyl-Wigner quantization scheme unifying P-Q and Q-P ordering and Weyl ordering of operators 被引量:1
7
作者 王继锁 范洪义 孟祥国 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期207-212,共6页
By extending the usual Wigner operator to the s-parameterized one as 1/4π2 integral (dyduexp [iu(q-Q)+iy(p-P)+is/2yu]) from n=- ∞ to ∞ with s beng a,real parameter,we propose a generalized Weyl quantization... By extending the usual Wigner operator to the s-parameterized one as 1/4π2 integral (dyduexp [iu(q-Q)+iy(p-P)+is/2yu]) from n=- ∞ to ∞ with s beng a,real parameter,we propose a generalized Weyl quantization scheme which accompanies a new generalized s-parameterized ordering rule.This rule recovers P-Q ordering,Q-P ordering,and Weyl ordering of operators in s = 1,1,0 respectively.Hence it differs from the Cahill-Glaubers’ ordering rule which unifies normal ordering,antinormal ordering,and Weyl ordering.We also show that in this scheme the s-parameter plays the role of correlation between two quadratures Q and P.The formula that can rearrange a given operator into its new s-parameterized ordering is presented. 展开更多
关键词 generalized Wigner operator generalized operator ordering rule bivariate normal dis-tribution
下载PDF
Distribution of driving trajectory of passenger car in highway horizontal curves
8
作者 任园园 李显生 +1 位作者 郭伟伟 王吉亮 《Journal of Beijing Institute of Technology》 EI CAS 2012年第2期222-228,共7页
In this paper the track behavior of passenger car was studied. The vehicle driving trajectory and driving direction were defined, and a classification of the type of vehicle trajectories along the curves was developed... In this paper the track behavior of passenger car was studied. The vehicle driving trajectory and driving direction were defined, and a classification of the type of vehicle trajectories along the curves was developed. The statistical parameters of vehicle trajectory samples in free flow and their frequency curves and cumulative frequency curves were achieved, K-S test and chi-square test were used to test normal distribution and gamma distribution for collected sample data, and the probabili- ty density functions were given. At last, dispersion degree between vehicle trajectory random varia- ble and the characteristic value of cumulative frequency curve in each key cross section in curves was analyzied. The proposed conclusion can provide theoretical support for the reasonable optimization of widen curve, design of alignment and the management of counter flow conflicts. 展开更多
关键词 traffic safety vehicle trajectory transverse deviation gamma distribution normal dis-tribution horizontal curve
下载PDF
Calculation of Nuclear Data for Proton Induced Reactions on ^(56)Fe and ^(57)Fe
9
作者 Xu Xiaoping Han Yinlu Zhuang Youxiang China Institute of Atomic Energy,P.O.Box 275(41),Beijing 102413 《Chinese journal of nuclear physics》 1997年第4期226-233,共8页
Available nuclear data(absorption cross sections,angular distributions,energyspectra,double differential cross sections of single particle emission and global sets of cross sec-tions of <sup>56,57</sup>Fe)... Available nuclear data(absorption cross sections,angular distributions,energyspectra,double differential cross sections of single particle emission and global sets of cross sec-tions of <sup>56,57</sup>Fe)are collected,evaluated and calculated by the new theoretical program.Goodagreements are obtained between the experimental data and the calculated data,respectively. 展开更多
关键词 Iron PROTON optical potential parameter Absorption CROSS SECTION Angular dis-tribution Energy spectrum Double differential CROSS section.
下载PDF
A Study on Mixed Effect Analysis of Polymeric Mixture by Means of Image Processing Technology
10
作者 许正军 《Journal of China Textile University(English Edition)》 EI CAS 1998年第4期71-73,共3页
The mixed effect analysis of polymeric mixture by means of image processing technology is discussed here. Since the integration of image and digital analysis, this method has the advantages of both perceptibility and ... The mixed effect analysis of polymeric mixture by means of image processing technology is discussed here. Since the integration of image and digital analysis, this method has the advantages of both perceptibility and objectivity. With pixel distribution as the main measurement of mixed effect, it indicates that the method of image pro-cessing technology is a new way to assess the mixed effect of polymeric mixture and the properties of all kinds of mixers. 展开更多
关键词 DISTRIBUTIVE mixing image processing GREY dis-tribution PIXELS statistics
全文增补中
“界面素化”策略改善铝基复合材料腐蚀性能 被引量:1
11
作者 戎旭东 李乐 +4 位作者 陈小丰 张翔 赵冬冬 何春年 赵乃勤 《Science China Materials》 SCIE EI CAS CSCD 2023年第11期4295-4305,共11页
添加增强相可以提高铝基复合材料的力学性能,但同时也会促进界面上原电池网络的形成,从而提升铝基复合材料的腐蚀敏感性.因此,优化界面结构是改善复合材料耐腐蚀性能的重要途径.对此,我们提出固相铝热反应结合热处理的策略,在Al-CuO复... 添加增强相可以提高铝基复合材料的力学性能,但同时也会促进界面上原电池网络的形成,从而提升铝基复合材料的腐蚀敏感性.因此,优化界面结构是改善复合材料耐腐蚀性能的重要途径.对此,我们提出固相铝热反应结合热处理的策略,在Al-CuO复合材料中构建包括晶界和增强体-基体界面在内的“素化界面”.本文通过浸渍/电化学腐蚀试验和微观结构表征系统研究了复合材料的晶间腐蚀行为和应力腐蚀开裂敏感性,强调了晶内分布纳米第二相(Al_(2)O_(3)增强相和Al-Cu沉淀相)对消除沿晶界连续原电池网络和阻断腐蚀路径的贡献.此外,研究发现具有低应变能且紧密结合的Al_(2)O_(3)-Al界面显著降低了局部腐蚀敏感性.这项工作阐明了复合材料界面特性与腐蚀机制之间的相关性,为发展耐腐蚀复合材料提供了新思路. 展开更多
关键词 INTERFACE Al matrix composite intragranular dis-tribution corrosion mechanism
原文传递
随机整数划分的概率分析(英文)
12
作者 苏中根 《数学进展》 CSCD 北大核心 2016年第6期861-898,共38页
令n≥1是自然数,它的一个整数划分是一列自然数λ_1,λ_2,…,λ_l(l≥1)使得λ_1+λ_2+…+λ_l=n.令P_n表示n的所有整数划分的集合,P表示所有整数划分的集合,通过赋予每个划分λ一个概率测度可以得到概率空间.特别地,有趣的概率测度包... 令n≥1是自然数,它的一个整数划分是一列自然数λ_1,λ_2,…,λ_l(l≥1)使得λ_1+λ_2+…+λ_l=n.令P_n表示n的所有整数划分的集合,P表示所有整数划分的集合,通过赋予每个划分λ一个概率测度可以得到概率空间.特别地,有趣的概率测度包括均匀测度和Plancherel测度以及乘性测度.这些整数随机划分的概率极限理论内容非常丰富.本文综述一些研究成果和进展,包括极限形以及波动.为叙述简单起见,主要集中在均匀划分和Plancherel划分,并且重点介绍两个模型中所用到条件概率的论证思想和方法,大多结果不加以详细证明. 展开更多
关键词 Gumbel分布 极限形 正态分布 Plancherel划分 tracy-widom分布 均匀划分
原文传递
Pore Structure Characteristics and Permeability of Deep Sedimentary Rocks Determined by Mercury Intrusion Porosimetry 被引量:10
13
作者 Na Zhang Manchao He +3 位作者 Bo Zhang Fengchao Qiao Hailong Sheng Qinhong Hu 《Journal of Earth Science》 SCIE CAS CSCD 2016年第4期670-676,共7页
Pore structure characteristics of rock are a great concern for researchers and practitioners in rock mechanics and rock engineering fields. In this study, mercury intrusion porosimetry(MIP) was used to measure pore ... Pore structure characteristics of rock are a great concern for researchers and practitioners in rock mechanics and rock engineering fields. In this study, mercury intrusion porosimetry(MIP) was used to measure pore size distribution, as well as several important index parameters of pore structure, for seven common types of deep sedimentary rocks with a total of fifty rock samples. Results show a similar pore size distribution pattern of the rock samples in the same lithological group, but remarkable differences among different lithological groups. Among seven investigated rock types, mudstone has the smallest porosity of 3.37%, while conglomerate has the largest value of 18.8%. It is also found that the porosity of rock types with finer grain size is lower than those with coarser grain size. Meanwhile, a comparison of frequency distribution at ten intervals of pore-throat diameter among seven types of sedimentary rocks reveals that different rock types have different dominant pore-size ranges. Furthermore, permeability of the investigated sedimentary rock samples was derived based on MIP data using reported theoretical equations. Among seven rock types, mudstone has the lowest averaged permeability(3.64×10^(-6) mD) while conglomerate has the highest one(8.59×10^(-4) mD). From mudstone to conglomerate, rock permeability increases with an increase of grain size, with only an exception of siltstone which has a relatively larger porosity value. Finally, regression analysis show that there is a good fitting(R^2=0.95) between permeability and porosity which could be easily used to derive reliable permeability values of similar kinds of engineering rocks. 展开更多
关键词 sedimentary rock pore structure mercury intrusion porosimetry (MIP) pore size dis-tribution porosity permeability.
原文传递
Precise Asymptotics for Random Matrices and Random Growth Models 被引量:7
14
作者 Zhong Gen SU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2008年第6期971-982,共12页
The author considers the largest eigenvaiues of random matrices from Gaussian unitary ensemble and Laguerre unitary ensemble, and the rightmost charge in certain random growth models. We obtain some precise asymptotic... The author considers the largest eigenvaiues of random matrices from Gaussian unitary ensemble and Laguerre unitary ensemble, and the rightmost charge in certain random growth models. We obtain some precise asymptotics results, which are in a sense similar to the precise asymptotics for sums of independent random variables in the context of the law of large numbers and complete convergence. Our proofs depend heavily upon the upper and lower tail estimates for random matrices and random growth models. The Tracy-Widom distribution plays a central role as well. 展开更多
关键词 Gaussian unitary ensemble Laguerre unitary ensemble largest eigenvalues random growth models tracy-widom distribution
原文传递
Exploring system architectures in AADL via POLYCHRONY and SYNDEx 被引量:2
15
作者 Huafeng YU Yue MA +4 位作者 Thierry GAUTIER LoYc BESNARD Jean-Pierre TALPIN Paul Le GUERNIC Yves SOREL 《Frontiers of Computer Science》 SCIE EI CSCD 2013年第5期627-649,共23页
Architecture analysis & design language (AADL) has been increasingly adopted in the design of em- bedded systems, and corresponding scheduling and formal verification have been well studied. However, little work ta... Architecture analysis & design language (AADL) has been increasingly adopted in the design of em- bedded systems, and corresponding scheduling and formal verification have been well studied. However, little work takes code distribution and architecture exploration into ac- count, particularly considering clock constraints, for dis- tributed multi-processor systems. In this paper, we present an overview of our approach to handle these concerns, together with the associated toolchain, AADL-PoLYCHRONY-SYNDEx. First, in order to avoid semantic ambiguities of AADL, the polychronous/multiclock semantics of AADL, based on a polychronous model of computation, is considered. Clock synthesis is then carried out in POLYCHRONY, which bridges the gap between the polychronous semantics and the syn- chronous semantics of SYNDEx. The same timing semantics is always preserved in order to ensure the correctness of the transformations between different formalisms. Code distri- bution and corresponding scheduling is carried out on the obtained SYNDEx model in the last step, which enables the exploration of architectures originally specified in AADL. Our contribution provides a fast yet efficient architecture ex- ploration approach for the design of distributed real-time and embedded systems. An avionic case study is used here to illustrate our approach. 展开更多
关键词 POLYCHRONY SIGNAL AADL SYNDEx architec-ture exploration modeling timing analysis scheduling dis-tribution
原文传递
The Moment Convergence Rates for Largest Eigenvalues of β Ensembles 被引量:2
16
作者 Jun Shan XIE 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2013年第3期477-488,共12页
The paper focuses on the largest eigenvalues of theβ-Hermite ensemble and theβ-Laguerre ensemble. In particular, we obtain the precise moment convergence rates of their largest eigenvalues. The results are motivated... The paper focuses on the largest eigenvalues of theβ-Hermite ensemble and theβ-Laguerre ensemble. In particular, we obtain the precise moment convergence rates of their largest eigenvalues. The results are motivated by the complete convergence for partial sums of i.i.d, random variables, and the proofs depend on the small deviations for largest eigenvalues of the β ensembles and tail inequalities of the generalβ Tracy-Widom law. 展开更多
关键词 β Ensembles largest eigenvalue moment convergence rate generalβ tracy-widom law
原文传递
Multiphase redistribution differences of polycyclic aromatic hydrocarbons (PAHs) between two successive sediment suspensions 被引量:1
17
作者 Rufeng LI Chenghong FENG +2 位作者 Dongxin WANG Baohua LI Zhenyao SHEN 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2016年第2期381-389,共9页
Successive sediment suspensions often happen in estuary, yet little research has probed into the difference in the release behaviors of organic compounds among different suspensions. This study took polycyclic aromati... Successive sediment suspensions often happen in estuary, yet little research has probed into the difference in the release behaviors of organic compounds among different suspensions. This study took polycyclic aromatic hydrocarbons (PAHs) as typical organic contaminants and investigated the release behaviors between two successive suspensions with a particle entrainment simulator (PES). Results showed that successive sediment suspensions lowered the concentration of dissolved PAHs in the overlying water via facilitating the re-adsorption of dissolved PAHs onto the suspended particles. Fast-release and slow-release periods of PAHs were successively observed in the both suspensions. The concentration changes of dissolved PAHs in the second suspension were generally similar with but hysteretic to those in the first suspension. More vigorous desorption and re-absorp- tion of PAHs were induced in the second suspension. Successive sediment suspensions obviously decreased the concentrations of mineral composition and organic matters in the overlying water, which significantly affects multi- phase distribution of PAHs. 展开更多
关键词 sediment suspension PAHS multiphase dis-tribution distribution coefficients
原文传递
Free energy fluctuations for a mixture of directed polymers
18
作者 SU ZhongGen 《Science China Mathematics》 SCIE CSCD 2017年第3期511-528,共18页
We study the free energy fluctuations for a mixture of directed polymers, which was first introduced by Borodin et al. (2015) to investigate the limiting distribution of a stationary Kaxdar-Parisi-Zhang (KPZ) equa... We study the free energy fluctuations for a mixture of directed polymers, which was first introduced by Borodin et al. (2015) to investigate the limiting distribution of a stationary Kaxdar-Parisi-Zhang (KPZ) equation. The main results consist of both the law of large numbers and the asymptotic fluctuation for the free energy as the model size tends to infinity. In particular, we find the explicit values (which may depend on model parameters) of normalizing constants in the fluctuation. This shows that such a mixture model is in the KPZ university class. 展开更多
关键词 free energy KPZ universality class log-Gamma directed polymer O'Connell-Yor semi-discretedirected polymer tracy-widom law
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部