期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
In-Network Puncturing for Delay-Efficient Rate Control of Distributed Video Coding in Wireless Video Sensor Networks 被引量:1
1
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
在线阅读 下载PDF
Pore Structure Characteristics and Permeability of Deep Sedimentary Rocks Determined by Mercury Intrusion Porosimetry 被引量:10
2
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
Bayesian Influence Assessments in a Growth Curve Model with General Covariance Structure 被引量:2
3
作者 BAI PENG PAN JIANXIN FEI YU 《应用概率统计》 CSCD 北大核心 1999年第1期53-62,共10页
The problem considered here is to assess the Bayesian influence on the unknown param-eter matrices in a grwoth curve model with the general covariance structure.Under the non-information prior distribution assumption,... The problem considered here is to assess the Bayesian influence on the unknown param-eter matrices in a grwoth curve model with the general covariance structure.Under the non-information prior distribution assumption,the Kullback-Leibler divergence is employed to eval-uate the effect of a designated response matrix on the posterior distribution of the parameter matrix. 展开更多
关键词 Groveth Curve Model General Covariance Structure Prior and Posterior dis-tribution Kullback-Leibler Divergence
在线阅读 下载PDF
Research on Spatial Pattern and Its Industrial Distribution of Commercial Space in Mianyang Based on POI Data 被引量:2
4
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
在线阅读 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
5
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
原文传递
Distribution of driving trajectory of passenger car in highway horizontal curves
6
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
在线阅读 下载PDF
Calculation of Nuclear Data for Proton Induced Reactions on ^(56)Fe and ^(57)Fe
7
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.
在线阅读 下载PDF
A Study on Mixed Effect Analysis of Polymeric Mixture by Means of Image Processing Technology
8
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
Exploring system architectures in AADL via POLYCHRONY and SYNDEx 被引量:2
9
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
“界面素化”策略改善铝基复合材料腐蚀性能 被引量:2
10
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
Multiphase redistribution differences of polycyclic aromatic hydrocarbons (PAHs) between two successive sediment suspensions 被引量:1
11
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
上一页 1 下一页 到第
使用帮助 返回顶部