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基于IP网络的业务流序列生成方法分析
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作者 钟曼莉 聂涛 《铁道学报》 EI CAS CSCD 北大核心 2003年第2期111-114,共4页
随着因特网的迅速增长,对其服务质量(QoS)的需求逐步增加。IP业务流的建模技术是QoS分析的基础。依照因特网的运行经验,业务流呈现自相似性质而不是非平稳泊松过程。本文介绍了自相似业务的特性,对产生自相似业务量的各种方法进行了分析... 随着因特网的迅速增长,对其服务质量(QoS)的需求逐步增加。IP业务流的建模技术是QoS分析的基础。依照因特网的运行经验,业务流呈现自相似性质而不是非平稳泊松过程。本文介绍了自相似业务的特性,对产生自相似业务量的各种方法进行了分析,给出了产生序列的详细步骤,并对这些方法进行了精度和复杂度的对比。 展开更多
关键词 自相似业务量 RMD方法 sar方法 FFT方法 Hosking方法
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合成孔径雷达配准方法研究
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作者 张彪 《地矿测绘》 2015年第4期3-6,共4页
文章首先回顾了基于强度互相关的配准方法和基于条纹清晰度的配准方法,并分析了合成孔径雷达配准方法存在的共性问题,然后提出了改进的SAR复数影像配准方法,最后通过一个案例进行分析,验证了采用偏移量标准偏差配准的影像在相关值和干... 文章首先回顾了基于强度互相关的配准方法和基于条纹清晰度的配准方法,并分析了合成孔径雷达配准方法存在的共性问题,然后提出了改进的SAR复数影像配准方法,最后通过一个案例进行分析,验证了采用偏移量标准偏差配准的影像在相关值和干涉图相位梯度方面都优于相关值加权方法。 展开更多
关键词 合成孔径雷达 配准方法 改进的sar复数影像配准方法
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OPTIMIZATION ON ANTENNA PATTERN OF SPACEBORNE SAR WITH IMPROVED NSGA-Ⅱ 被引量:2
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作者 Xiao Jiang Wang Xiaoqing +1 位作者 Zhu Minhui Xiao Liu 《Journal of Electronics(China)》 2009年第4期443-447,共5页
Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NS... Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NSGA-Ⅱ), is applied on a spaceborne SAR antenna pattern design. The system consists of two objective functions with two constraints. Pareto fronts are generated as a result of multi-objective optimization. After being validated by a test problem ZDT4, the algorithms are used to synthesize spaceborne SAR antenna radiation pattern. The good results with low Ambi- guity-to-Signal Ratio (ASR) and high directivity are obtained in the paper. 展开更多
关键词 Synthetic Aperture Radar sar Radiation pattern Improved Non-dominated Sorting Genetic Algorithms (NSGA)-Ⅱ Ambiguity-to-Signal Ratio (ASR)
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计算机辅助药物设计 被引量:5
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作者 袁身刚 《科学》 1995年第5期28-31,59,共5页
对已有药物的优化改造,从动植物体内分离生物活性物质,依赖于筛选模型的大规模筛选法和基于假设或作用机理的药物设计构成了新药的四大主要来源。其中尤以筛选法为当前开发新药的首要途径,但其低效和费时费钱限制了新药的开发。资料表... 对已有药物的优化改造,从动植物体内分离生物活性物质,依赖于筛选模型的大规模筛选法和基于假设或作用机理的药物设计构成了新药的四大主要来源。其中尤以筛选法为当前开发新药的首要途径,但其低效和费时费钱限制了新药的开发。资料表明筛选的成功率仅在1/15000左右,找到一个新药的化费超过1亿美元,周期长达8~12年。因此,药学家长期以来希望能通过合乎逻辑地深思熟虑和系统化地搜索或计算。 展开更多
关键词 合理药物设计 sar/Qsar方法 结构生成 计算机
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确定股市趋势的方法-SAR
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作者 刘虹俊 《证券导刊》 2005年第16期77-78,共2页
漫步华尔街专栏由华尔街资深金融专家刘虹俊先生担纲主持。刘先生现仍在美国华尔街从事资产管理和投资银行业务,刘先生希望通过本专栏将其十几年华尔街成功经验和独到见解与读者共享。
关键词 华尔街 投资银行业务 资产管理 股市 金融专家 成功经验 独到见解 sar方法 加速极限 机构投资人
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Monitoring cyanobacteria-dominant algal blooms in eutrophicated Taihu Lake in China with synthetic aperture radar images 被引量:5
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作者 王甘霖 李俊生 +2 位作者 张兵 申茜 张方方 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第1期139-148,共10页
Monitoring algal blooms by optical remote sensing is limited by cloud cover.In this study,synthetic aperture radar(SAR) was deployed with the aim of monitoring cyanobacteria-dominant algal blooms in Taihu Lake in clou... Monitoring algal blooms by optical remote sensing is limited by cloud cover.In this study,synthetic aperture radar(SAR) was deployed with the aim of monitoring cyanobacteria-dominant algal blooms in Taihu Lake in cloudy weather.The study shows that dark regions in the SAR images caused by cyanobacterial blooms damped the microwave backscatter of the lake surface and were consistent with the regions of algal blooms in quasi-synchronous optical images,confirming the applicability of SAR for detection of surface blooms.Low backscatter may also be associated with other factors such as low wind speeds,resulting in interference when monitoring algal blooms using SAR data alone.After feature extraction and selection,the dark regions were classified by the support vector machine method with an overall accuracy of 67.74%.SAR can provide a reference point for monitoring cyanobacterial blooms in the lake,particularly when weather is not suitable for optical remote sensing.Multi-polarization and multi-band SAR can be considered for use in the future to obtain more accurate information regarding algal blooms from SAR data. 展开更多
关键词 synthetic aperture radar sar Taihu Lake CYANOBACTERIA algal blooms support vector machine
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评《SARS医学中的物理热学方法与应用》
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作者 王洪武 《科学通报》 EI CAS CSCD 北大核心 2004年第11期1061-1061,共1页
关键词 sarS医学中的物理热学方法与应用》 书评 非药物性物理热学 热学诊断 热学治疗
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Denoising of SAR Images Based on Lifting Scheme Wavelet Packet Transform 被引量:1
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作者 WANG Wenbo YI Xuming FEI Pusheng 《Geo-Spatial Information Science》 2008年第4期257-261,共5页
According to the different characteristics that signal and noise exhibit during wavelet decomposition, a new denoising method based on the lifting scheme wavelet packet decomposition is presented. In this method, the ... According to the different characteristics that signal and noise exhibit during wavelet decomposition, a new denoising method based on the lifting scheme wavelet packet decomposition is presented. In this method, the SAR images are decom- posed by using the best wavelet packet and the norm of each sub-band are calculated; signals and noise can be discriminated based on the norm and soft-threshold method, and the images can be denoised. Experiments show that the proposed algorithm has excellent performance in denoising SAR images, and can remove most noise of images with well-kept texture detail informa- tion. The calculating speed of the method is twice the speed of the general wavelet packet transform algorithm. 展开更多
关键词 lifting scheme wavelet packet decomposition sar image image denoising
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A feature extraction method for synthetic aperture radar(SAR) automatic target recognition based on maximum interclass distance 被引量:2
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作者 WANG Bing HUANG YuLin +1 位作者 YANG JianYu WU JunJie 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第9期2520-2524,共5页
Synthetic aperture radar(SAR) automatic target recognition is an important application in SAR.How to extract features has restricted the application of SAR technology seriously.In this paper,a new feature extraction m... Synthetic aperture radar(SAR) automatic target recognition is an important application in SAR.How to extract features has restricted the application of SAR technology seriously.In this paper,a new feature extraction method for SAR automatic target recognition based on maximum interclass distance is proposed,which integrates class and neighborhood information.This method can reinforce discriminative power using maximum interclass distance,so it can improve recognition rate effectively. 展开更多
关键词 synthetic aperture radar sar automatic target recognition (ATR) manifold learning feature extraction
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Recent progress in Bistatic SAR with illuminators of opportunity
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作者 ZENG Tao ZHANG Tian +1 位作者 TIAN Wei Ming HU Cheng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第12期1965-1967,共3页
Bistatic SAR(Bi SAR)with illuminators of opportunity is a kind of flexible SAR system that consists of non-cooperative transmitters and a stationary or moving receiver,as Figure 1shows.In recent years,notable effort... Bistatic SAR(Bi SAR)with illuminators of opportunity is a kind of flexible SAR system that consists of non-cooperative transmitters and a stationary or moving receiver,as Figure 1shows.In recent years,notable efforts have been made to promote the development of this kind of system.Progress regarding Bi SAR with navigation satellites as transmitters before 2015,including the related theory and practice,has been well reviewed by Antoniou et al.and can be referred from[1].This paper reviews some of the progress in 2015and 2016,including novel signal processing approaches,advanced Bi SAR system configurations and potentially 展开更多
关键词 opportunity stationary receiver navigation potentially cooperative iterative Figure subsidence utilized
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A nonparametric estimation of the infection curve
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作者 LIN HuaZhen YIP Paul S. F HUGGINS Richard M 《Science China Mathematics》 SCIE 2011年第9期1815-1828,共14页
Predicting the future course of an epidemic depends on being able to estimate the current numbers of infected individuals.However,while back-projection techniques allow reliable estimation of the numbers of infected i... Predicting the future course of an epidemic depends on being able to estimate the current numbers of infected individuals.However,while back-projection techniques allow reliable estimation of the numbers of infected individuals in the more distant past,they are less reliable in the recent past.We propose two new nonparametric methods to estimate the unobserved numbers of infected individuals in the recent past in an epidemic.The proposed methods are noniterative,easily computed and asymptotically normal with simple variance formulas.Simulations show that the proposed methods are much more robust and accurate than the existing back projection method,especially for the recent past,which is our primary interest.We apply the proposed methods to the 2003 Severe Acute Respiratory Syndorme(SARS) epidemic in Hong Kong. 展开更多
关键词 EPIDEMIC BACK-PROJECTION nonparametric method infection curve
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