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1.
利用HJ-1B模拟数据反演地表温度的两种单通道算法   总被引:7,自引:0,他引:7  
现有的两种单通道算法(覃志豪单通道算法和Jimenez-Munoz&Sobrino单通道算法)都是针对LandsatTM提出的,中国即将发射的HJ-1B卫星传感器也仅有一个热红外波段,要想应用这两种算法对HJ-1B数据进行地表温度的反演,需要根据HJ-1B热红外波段的通道响应函数来重新得到算法中的经验关系.文中针对HJ-1B卫星传感器对这两种算法进行了修订,通过大气辐射传输软件MODTRAN4模拟数据对算法进行了精度评价和参数的敏感性分析.并在此基础上考虑HJ-1B卫星传感器的噪声等效温差(NE△T)和各种参数的估计误差对算法进行了综合误差分析,发现在NE△T≤0.3K的情况下,覃志豪单通道算法平均综合误差为1.14K,而Jimenez-Munozoz&Sobrino单通道算法平均综合误差为0.94K.基于模拟的HJ-1B热红外波段数据,采用修订后的算法进行了地表温度的反演实验,通过对反演结果的分析,发现覃志豪单通道算法反演的地表温度比模拟的地表温度低1.2K左右,而Jimenez—Munozoz&Sobrino单通道算法比模拟的地表温度低0.8K左右.从算法验证和应用的结果来看,修订的这两种算法可以方便地应用到对HJ-1B热红外波段数据的地表温度反演.  相似文献   

2.
基于群体的进化算法是求解函数优化问题的常用方法,但存在收敛速度慢和易陷入早熟的缺点.提出了一个基于(1+1)-ES分块进化的低维函数优化算法,采用分块进化,引入丢弃不重要分块和二次优化求精的策略,实现了全局搜索过程和局部搜索过程的分离.通过算法分析,表明了算法比较适合于低维函数.仿真结果表明了提出的算法的抗早熟能力和求解效率均优于FEP.  相似文献   

3.
研究三台平行同类机在线排序问题的一种特殊情形,即三台同类机的加工速度分别为s1=s2=1,s3=s≥1.利用“总加工时间”这一部分信息来设计算法,证明了该算法的竞争比为(s 2)/s~(1/2).结合文献中曾有的关于此问题在线算法的下界,可以知道当S≥2时,该算法比可能有的最好的在线算法在性能上要好.  相似文献   

4.
介绍了改进的MODIS海洋气溶胶反演算法,并重点对该算法进行了验证,结果表明:(1)改进算法纠正了原算法对较大的气溶胶光学厚度的低估和对较小的气溶胶光学厚度的高估现象;其反演得到的气溶胶光学厚度与AERONET的气溶胶光学厚度的相关系数为0.87,高于原算法与AERONET间气溶胶光学厚度的相关系数(0.84);且有62.1%的反演结果落在误差限内,高于原算法的60.5%。(2)改进算法纠正了原算法对较大的气溶胶尺度分布参数ηss0的低估和较小的气溶胶尺度分布参数卵。的高估现象;其反演得到的气溶胶尺度分布参数与AERONET的气溶胶尺度分布参数的相关系数为0.89,高于原算法与AERONET间气溶胶尺度分布参数的相关系数(0.8)。  相似文献   

5.
在G.729.1宽带语音编码算法中,时域混叠编码器的谱包络编码根据帧内子带的相关性,采用差分霍夫曼编码来减少编码的比特分配。针对相邻帧对应子带的谱包络存在相关性,给出了在原有谱包络编码模式的基础上,增加一种帧间对应子带差分霍夫曼编码的模式来进一步减少谱包络的编码比特数,从而提高合成语音的质量。由于G.729.1可以根据信道的特征随时调整编码速率以取得更好的宽带语音质量,这使得该编码算法具有很高的复杂度。为了能在数字信号处理器(digital signal processor,DSP)上实时实现G.729.1,结合TMS320VC5505数字信号处理器对G.729.1算法采用全汇编实现,并对汇编后的G.729.1代码做了进一步的汇编优化,优化后的G.729.1算法在保证了高质量语音输出的同时,提高了编码效率,实现了对语音信号的实时处理。  相似文献   

6.
改进Huffnan算法,提出了多叉树Huffnan算法.理论分析表明该算法优于常规的Huffnan算法,其平均码长已接近信源的熵函数值,且其解码速度快.将其实现用于文本压缩,压缩比大约为3:1左右.该算法已长期用于众多产品中,取得了良好的效果。  相似文献   

7.
本文在文献[1]的基础上,引入模糊数学思想,提出了一种全新的求解多目标规划算法.其不仅简化了文献[1]的算法过程,还解决了如何判断解的有效性问题.  相似文献   

8.
提出了一种新的裁剪算法,并讨论了算法的正确性和可靠性.该算法是文献[1]的改进,裁剪速度比[1]快。  相似文献   

9.
对最优化方法中的梯度算法进行了改进.当2f/x2=≠0时,将二阶导数与梯度方向相结合,构造出一种新的下降方向d=[1+δ/(2f/x2)](f/x),其中δ=1或-1.用新的下降方向设计了一种算法,使梯度法得到改进.新的算法比梯度法的收敛速度快,而且比牛顿法计算量小.  相似文献   

10.
利用“ ”函数的光滑近似函数和无约束优化方法给出非线性l1的一种算法.在适当的假设下,算法是全局收敛的.初步的数值试验结果表明算法的有效性.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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-  相似文献   

18.
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-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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