小波分析在径流时间序列预测的应用

利用dmey小波变换、db4小波变换将柳江年径流总量及年最大径流量时间序列分别分解为不同尺度的频率信号,再使用传统时间序列分析方法对径流分解的频率信号分别设置参数并进行预测,最后利用小波逆变换对预测结果进行重构,以此建立年径流总量、年最大径流量预测模型.与只采用传统的时间序列预测模型对比,联合了小波变换的方法均获得更精确的预报结果.计算结果表明将小波变换运用于径流时间序列的预测能有效提高径流变化趋势预测的准确率,预报的稳定性以及精确度均能明显改善.     

一种改进的地震波信号去噪方法

从复杂地震波背景中提取单频信号问题出发,分析比较了经典的傅里叶变换滤波和传统小波变换去噪方法的局限性。根据地震波环境噪声不会突变的特点,采用震源发射信号的前几秒种所采集的噪声样本作为整个信号处理过程中的噪声信号。采用小波包变换去噪方法,先分别获取噪声系数和信号加噪声系数,然后从总系数中减去噪声系数,得到信号的系数,再根据这组系数对信号进行重构,获得很好的去噪结果。将此方法应用于落重产生的地震波信号的提取中,为后续地震波信息的利用提供了基础。     

9-7小波的一种新的有效算法

以构造双正交小波的Cohen-Daubechies-Feauveau定理为基础，利用提升方法构造了一组对称双正交9．7小波滤波器．它与JPEG2000中采用的CDF9-7小波压缩性能几乎相同，并且它们两者在图像压缩中可以互相作正变换与逆变换．新9-7小波的计算只需要2个浮点运算和16个整数运算，而CDF97小波需要14个浮点运算，因而它能极大简化和减少图像压缩和视频压缩的运算量．     

线调频小波变换及其应用

线调频小波变换是一种新的线性时频分析方法．在介绍线调频小波变换的基础上，比较了短时傅里叶变换、连续小波变换、线调频小波变换在瞬时频率计算方面的优缺点．最后给出了在石油勘探开发中利用线调频小波变换对沉积旋回信号进行分析的一些初步应用．     

基于多尺度小波的城市遥感图像纹理特征提取

遥感技术为人们提供了大量的图像数据,如何从中提取所需信息,是遥感图像处理技术研究的热点。基于多尺度小波变换,可提取城市图像的纹理特征。根据城市影像中地物特征和小波技术的特点,确定合适的窗口大小,采用逐一滑动窗口的方法,对每一窗口提取相应的小波统计特征;应用小波变换的多尺度特性,在不同尺度上提取出子图像特征,构造出纹理特征矢量,为遥感图像的分类提供纹理特征。     

一类小波框架的设计

小波变换包括连续小波变换和离散小波变换.而离散小波变换的主体部分是关于小波框架的理论.本文对小波框架做简单介绍,并对构造小波框架的已有理论加以推广并证明之.     

基于小波变换实现图像放大方法研究

提出了一种基于小波变换的图像放大方法。针对以往利用小波变换进行图像放大所导致的变换后图像整体灰度变暗和图像边缘失真现象,对其进行了分析并加以改正,设计了构造小波逆变换所需低频分量和高频分量的方法。实验结果表明,用该方法进行处理所得到的放大图像具有较好的视觉效果。     

小波变换方法及其在化学中的应用

本文较为详细地介绍了小波变换的数学原理和快速实现方法-Mallat算法,对小波在化学中的信号去噪、奇异性分析、谱图数据压缩、模式识别和预测、理论化学研究等方面的应用作一概述,并简要展望了小波在化学中应用前景.     

基于小波变换的暂态电能质量扰动的检测法

该文研究了基于小波变换的暂态电能质量扰动的检测算法,利用快速小波变换算法即Mallat算法检测和提取扰动信号,并在MATLAB环境下进行了仿真,采用db4小波、3尺度进行小波分解与重构并对信号进行检测,验证了小波变换能够实现电能质量扰动信号的准确定位。     

小波CWT-MLP网络预测负荷方法改进

为提高对短期负荷的预测精度,提出基于小波变换,并加入电价因子构建MLP神经网络对负荷进行短期预测的方法。首先通过小波变换将原始负荷、电价序列进行分解,得到高、低频率的时间序列带;其次分别利用高频、低频电价序列对高频、低频负荷序列进行MLP神经网络训练与预测;最后,将预测的高频、低频负荷值通过小波变换,重构完整的负荷预测值。采用美国电力联盟实例对该方法进行验证,并与含电价因子的MLP网络预测法、经典MLP网络预测法,以及不含电价因子的CWT-MLP网络预测法预测效果进行比较。结果证明,含有电价因子,并结合小波与MLP神经网络构建的模型能够丰富数据信息,提高负荷预测精度。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.