幼儿园教育改革政策落实过程中的误区透析——从文本传递质量看改革成效     

刘丽湘  刘焱 《学前教育研究》2008,(12)

本文针对我国幼儿园教育改革需要深化与发展的形势,分析了我国幼儿园教育改革政策落实过程中文本传递的质量,提出了分析幼儿园教育改革文本传递过程的内容分析框架,并透析了当前幼儿园教育改革在文本传递上的特点与误区,进而提出了教育改革成效的监控重点。  相似文献   

Time-frequency channel modeling and estimation of multi-carrier spread spectrum communication systems     

Seda ?enay  Luis F. Chaparro 《Journal of The Franklin Institute》2005,342(7):776-792

In wireless communications, the channel is typically modeled as a random, linear, time-varying system that spreads the transmitted signal in both time and frequency due to multi-path propagation and Doppler effects. Estimated channel parameters allow system designers to develop coherent receivers that increase the system performance. In this paper, we show how time-frequency analysis can be used to model and estimate the time-varying channel of a multi-carrier spread spectrum (MCSS) system using a complex quadratic sequence as the spreading code. We will show that for this spreading code, the effects of time delays and Doppler frequency shifts, caused by the mobility of environment objects, can be combined and represented effectively as time shifts. The discrete evolutionary transform (DET), as a time-frequency analysis method, enables us to estimate the effective time shifts via a spreading function and to use them to equalize the channel. Using the effective time shifts, the time-varying channel can be represented simply as linear-time invariant system by embedding the Doppler shifts that characterize the time-varying channel into effective time shifts. The channel parameters are used to estimate the data bit sent. To illustrate the performance of the proposed method we perform several simulations with different levels of channel noise, jammer interference, and Doppler frequency shifts.  相似文献   

小波双线性插值应用于光学遥感图像   总被引：8，自引：0，他引：8  

刘笑宙  涂国防 《中国科学院研究生院学报》2003,20(1):39-43

针对遥感图像插值要求,尽可能保持原图像信息,提高图像分辨率,并适合人眼观察的特点,提出适合于遥感图像的小波双线性插值方法.实验表明,与双线性插值相比,该算法得到较高的信噪比和较好的图像效果.  相似文献   

基于小波变换的电网谐波检测     

刘静  朱更军 《科技广场》2005,(3):113-115

电网的谐波检测，一直是电力工作者研究的一项重要课题。本文介绍了电力系统中目前已有的几种主要的谐波检测方法，探讨了小波变换理论在谐波检测中的应用。  相似文献   

中职数学教学中数学思想的挖掘与渗透点滴谈     

刘永旺 《宁德师专学报(自然科学版)》2011,23(2):186-188,200

数学教学在向学生展示获取知识、技能及解决问题的思维过程的同时,不仅要善于＂挖掘＂教材中蕴含的数学思想和数学方法,还要使数学思想方法的渗透自然地贯穿于整个教学过程中.  相似文献   

Generalized solutions to the Benjamin-Ono equations in sense of Colombeau     

金小刚  杨建刚  蔺杰 《Journal of Zhejiang University. Science. B》2004,(11)

INTRODUCTION In the theory of partial differential equations,Schwartz distribution theory and Sobolev spacesplay a very important role. But one shortcoming ofdistribution theory, however, is its inability to solvenonlinear problems because the product of distri-butions may not be a distribution. The need to de-fine the product of distributions also arises withproblems in Dirac’s quantum theory of an elec-tromagnetic field. It is impossible to introduce anassociate multiplication i…  相似文献   

Generalized solutions to the Benjamin-Ono equations in sense of Colombeau     

金小刚  杨建刚  蔺杰 《浙江大学学报(A卷英文版)》2004,5(11):1466-1470

This paper discusses the existence and uniqueness of the generalized solution in the sense of Colombeau to the Benjamin-Oho(B-O)equation and the relationship between the new generalized solution and the classical solution.  相似文献   

Wavelet transforms: Application to data analysis - I     

Jatan?K.?Modi  Sachin?P.?NanavatiEmail author  Amit?S.?Phadke  Prasanta?K.?PanigrahiEmail author 《Resonance》2004,9(11):10-22

In this article, we elaborate upon the key ideas underlying the construction of various wavelet basis sets. The roles of translation and scaling, which enable the wavelets to localize variations at desired levels of resolution, are clearly brought out. After explaining the implementation of one dimensional wavelet transform, we illustrate their usefulness through the analysis of a data set.  相似文献   

基于多小波变换的数字水印嵌入方法     

吴爱弟  王明春 《天津工程师范学院学报》2007,17(4):5-7

提出了一种基于多小波变换的数字水印算法,将二值水印嵌入到宿主图像的多小波变换域中。首先将对应于相同位置的多小波系数形成向量序列,然后采用均值量化方法嵌入数字水印。实验结果表明,该水印算法在多种攻击下都具有较好的鲁棒性。  相似文献   

Watermarking on 3D mesh based on spherical wavelet transform   总被引：3，自引：0，他引：3  

金剑秋  戴敏雅  鲍虎军  彭群生 《Journal of Zhejiang University. Science. B》2004,(3)

INTRODUCTIONTherapidgrowthofdigitalmediaoverInternetprovideseverybodywiththefacilityofeasyaccess,copy,editanddistributionofdigitalcontentssuchaselectronicdocuments,images,soundsandvideos.Thereisurgentdemandfortechniquestoprotectthecopyrightoftheoriginaldigitaldataandtopreventunauthorizedduplicationortampering.Digitalwatermarkingordatahidingisonesolutionforthecopyrightprotectionofdigitaldata.Digitalwatermarkingisaprocessbywhichauser-specifiedsignal(watermark)ishiddenorembeddedintoanothersi…  相似文献