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1.
研究由低维非线性动力系统所产生的混沌时序的预测方法及其应用。通过改进的最小二乘方法来估计模型的参数,并在其相空间中对时序的未来值进行预测。给出了有代表性的实例对本文的模型和算法进行验证。结果发现选取最佳的模型阶数能增加预测的准确程度,且混沌时序不可能进行长期的预测。算例表明本文建议的方法是有效的。  相似文献   

2.
基于小波网络的非线性经济时序预测模型   总被引:1,自引:1,他引:0  
为对经济时序准确预测,必须先对其数据结构进行分析,相空间重构技术为之提供了理论基础,通过关联维数的计算,区分确定性系统和随机系统.在此基础上确定最佳嵌入维数、最佳采样时间间隔及小波元的个数,并通过带有偏差单元的递归小波网络的学习,进行模型参数的辨识.实验研究表明,模型对非线性经济时序具有良好的逼近能力,因此该模型用于非线性经济时序预测具有可行性。  相似文献   

3.
利用相位随机化的替代数据方法研究了2种不同分布的随机分数对动力系统实测时序数据判值影响的程度。计算结果表明:相位的充分随机分可以提高判别的准确程度,把此判据用于随机时序与非线性混沌时序所得的判值有明显的差异,且不同分布的随机数相位充分随机化后对临界值无质的影响。  相似文献   

4.
应用1964~1995年东川市人均粮食资料,重构其嵌入相空间序列,探讨了其时序的分形特征,并计算了其平均可预报年限.结果表明,东川市人均粮食的时序分布具有分形特征,且该时序是一混沌序列,其饱和关联维数约为3.1631,系统的有效自由度数为8个,平均可预报尺度不超过27~28年.研究结果为人均粮食的时序预测预报模型提供了依据.  相似文献   

5.
基于时序机全分解理论研究,文章给出了时序机串行全分解中NS型全分解的实现和优化过程  相似文献   

6.
时序逻辑电路中的竞争冒险   总被引:1,自引:0,他引:1  
分析了异步时序逻辑电路和同步时序逻辑电路中的竞争冒险现象,给出了消除竞争冒险的方法和途径.  相似文献   

7.
根据引信安全系统理论,研究了组成安全系统的各保险要素之间的相互关系及其共同性质,提出了一种普遍适用的分析和确定保险要素之间的时序逻辑关系-S-L图法,并通过几个示例用S-L图法分析了安全系统保险要素之间的时序逻辑关系,最后给出了两个重要的推论。结果表明,这种方法为分析和确定引信安全系统保险要素及其作用关系,提供了一种直观有效的研究手段。  相似文献   

8.
根据经济时序的非线性、非平稳性和离散性及传统时序滤波方法在经济时序滤波应用中存在的局限性,应用估计熵的基本特性,提出一种基于估计熵的滤波方法,探讨了该滤波方法的原理和应用过程,并以实际的GDE时序为例,做出该滤波方法的案例分析,案例分析表明,基于估计熵的滤波方法比传统的时序滤波方法有较好的滤波效果。  相似文献   

9.
关于时序模式发现算法的研究   总被引:1,自引:1,他引:0  
数据挖掘归属于决策系统,可以从浩瀚的数据库中挖掘出不易被发现的有用信息,并且可以进行预测,为管理层中决策者的决策提供科学依据。针对时序数据中的复杂模式问题,提出了一种时序模式算法,并描绘了算法的基本思想及给出了算法的简单伪代码。在用程序实现后,对算法的优劣进行了分析,为进一步改进和完善算法或者为寻找更为理想的算法提供了有益的启示。  相似文献   

10.
本文提出求解Winer-Hopf积分方程的一种时序方法,并应用这种方法来综合最佳线性过滤器。它不仅可直接应用于以图象或数列给出的相关函数,更主要是可避免为解决可实现性问题而遇到的困难。  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.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  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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