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1.
在分析了基于信干比(CIR)估计的链路自适应算法的基础上,指出该算法的性能取决于如何对下一调整间隔的CIR值进行预测,提出了CIR的线性预测算法,并在此基础上将自适应滤波理论引入到CIR的预测中,提出了适合于CIR预测的自适应算法,分析了此种情况下的收敛因子和其他参数的选取。数值仿真结果表明,自适应预测算法明显优于简单预测与线性预测算法,特别是在CIR估计存在误差时,优势更加明显,其吞吐量的最大增幅超过了5Mbit/s。需要指出的是,虽然本文的分析和仿真均以HIPERLAN2为例,但其结果对于在WPAN/WLAN应用环境下的其他系统也都适用。  相似文献   

2.
提出了一种将多神经网络,自适应控制和预测控制相结合的方法,用以解决复杂系统的控制问题,并从数学模型、网络结构及算法进行了研究、最后给出了模拟结果。  相似文献   

3.
自适应噪声抵消器频域优化设计及其应用分析   总被引:1,自引:1,他引:0  
随着通信技术的发展,自适应噪声抵消器在现在信号处理中得到越来越广泛的应用.在分析和讨论自适应噪声抵消器原理基础上,详细研究了基于自适应滤波器技术的噪声抵消优化实现算法及其特性.最后,以胎儿心电图信号检测为例,分析了自适应噪声抵消技术的应用,在MATLAB环境下进行测试分析,模拟测试结果与理论分析预测吻合.  相似文献   

4.
用于电视信号帧内DPCM编码的非自适应预测器在图象的轮廓与边缘处经常导致大的预测误差,因此,它不适用于轮廓及细节丰富的图象。本文在轮廓预测的基础上提出一种新型的自适应预测器,图象的平坦部分及轮廓分别用不同的预测算法预测。预测器的自适应转换只利用前已传送的图象信息,不需向接收端另外传送附加的开关信息。该预测器的性能通过计算机模拟与其它已知的非自适应及自适应预测器进行了客观定量比较与主观试验。所建议的新的预测算法显著地降低了大预测误差的出现频数。与其它帧内预测器比较,采用这一新的预测器可以获得更大的码率压缩。  相似文献   

5.
水声多径时延的自适应参数估计   总被引:2,自引:0,他引:2  
从浅海声信道的特性出发,研究水下声信道的多径时延,提出自适应模型,给出水声信道自适应模拟的方法,以达到对水声多径信道的计算机模拟。模型的建立适合于自适应算法,较为简洁,在保证估计精度的情况下,可减少计算量,为水声信道的研究提供一种途径。  相似文献   

6.
为了对污水处理生物过程中曝气池内溶解氧进行准确的实时预测,分别应用自适应神经网络模糊推理系统(ANFIS)和BP神经网络建立了针对曝气池溶解氧的预测模型,并进行了对比研究。结果表明,用自适应神经模糊推理系对曝气池溶解氧的预测,在模拟误差和收敛性方面,均好于单纯的BP神经网络。  相似文献   

7.
针对机电设备运行状态受多因素影响且变化趋势复杂、难以用单一预测方法进行有效预测的问题,提出了一种新的基于经验模式分解、支持向量机和自适应线性神经网络的混合智能预测模型.首先,利用经验模式分解方法将非平稳时间序列按其内在的时间特征尺度自适应地分解为多个本征模式分量,然后根据这些分量各自趋势变化的剧烈程度选择合适的核函数,用支持向量机对其进行预测,最后通过自适应线性神经网络对这些预测分量进行自适应加权组合,得到原始序列的预测值.研究结果表明,对于标准算例和某机组振动趋势的预测,不论是单步预测还是多步预测,该模型的预测性能均好于单一的支持向量机预测方法。  相似文献   

8.
本文将自适应Lasso与组Lasso进行结合得到了自适应组Lasso,给出了拥有自适应组Lasso惩罚项的logistic模型的相关概念及其符号表示;运用坐标梯度下降算法给出了模型的求解方法;数值模拟表明了该方法在变量选择以及模型预测中的优势.  相似文献   

9.
SDH中恢复四次群时钟的数字化预处理方法   总被引:1,自引:0,他引:1  
同步数字系列(SDH)中的指针调整引入了8bit或24bit的大幅度抖动。为了处理这一抖动,提出了一种数字化处理方法——自适应预测法,可以作为预处理方法应用于SDH中的四次群时钟恢复。该方法在一个统计周期内统计指针调整和码速调整的次数,并根据统计结果,在下一个周期内自适应地预测出四次群支路时钟。该时钟不含指针抖动,便于利用模拟锁相环进行最终处理,得到均匀的四次群时钟。从该方法的基本原理,以及对它的静态抖动和抖动转移性能分析中可知,相对于以往的减小指针抖动的方法,如比特泄漏法等,自适应预测法具有输出抖动小,抖动转移性能好,捕捉范围宽等特点。  相似文献   

10.
生态经济系统是经济子系统、社会子系统、生态环境子系统相耦合的复杂巨系统。本文以模糊推理系统和BP神经网络相结合的自适应神经模糊推理系统(ANFIS)来模拟生态经济系统的功能,进行预测。通过利用1991年-2003年杭州市生态经济可持续发展评价指标体系中的一系列指标值,确定7个指标,采集1992年-2004年的数据,构建模型,进行训练、检验,建立了以杭州市为代表的基于ANFIS的可持续发展预测控制模型。  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.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
<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   

19.
20.
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has  相似文献   

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