微弱信号提取中的小波方法研究

针对于实际应用中的小信号特别是完全被噪声淹没情况下的微弱信号提取的问题，本文依据白噪声信号的小波变换系数相对比有用信号的小波系数小的特点，利用小波变换对信号进行消噪来提取微弱信号，仿真结果表明：小波变换能够有效的消除噪声，将有用微弱信号从受噪声污染的信号中提取出来。     

一种微弱信号的检测技术

针对于实际应用中的小信号,特别是完全被噪声淹没情况下的微弱信号提取问题进行了论证,分析了信号和噪声在时间特性方面和统计特性上的差别,介绍了一种有效的用相关函数检测技术来提取被噪声淹没的极微弱信号的方法.     

一种微弱信号的检测技术

针对于实际应用中的小信号,特别是完全被噪声淹没情况下的微弱信号提取问题进行了论证,分析了信号和噪声在时间特性方面和统计特性上的差别,介绍了一种有效的用相关函数检测技术来提取被噪声淹没的极微弱信号的方法.     

小波包变换及其在低信噪比雷达信号检测中的应用

雷达对目标进行检测之时，常常遇到目标回波信号被噪声污染的问题。为了把弱目标信号从强噪声背景中检测出来，对小波包变换良好的时频分析特性进行了分析，根据信号与噪声具有不同的Lipschitz指数，通过引入子频带∞-范数，对信号和噪声进行频谱分析，将最佳子空间的熵值及最佳子空间在完整二叉树中的位置参数作为特征量，应用浮动阈值去噪方法，解决了低信噪比情况下的雷达信号检测。最后，通过计算机的数值计算，模拟了小波包变换和小波变换在低信噪比雷达信号检测中的具体应用，得出了在低信噪比信号检测方面小波包变换优于小波变换的结论。     

一种语音增强算法的研究

采用基于子空间的方法，对语音信号进行增强处理，该算法提供了在语音信号失真和残留噪声之间进行控制的机制。克服了以往语音增强算法中对语音信号的噪声特点的限制，可以对混有加性白噪声、有色噪声和音乐噪声的语音信号进行增强处理。     

含冲击的车内道路噪声主动控制系统

针对道路噪声主动控制系统中，冲击噪声引起的鲁棒性问题，提出了一种对冲击噪声的主动控制方法。首先，进行了道路噪声采集试验，选取了4个最佳参考信号位置，并采集了道路冲击噪声的数据。然后，基于多通道自适应滤波算法，提出了归一化多通道自适应滤波算法和符号算法相结合的冲击噪声主动控制算法。其次，基于提出的冲击噪声主动控制算法，搭建了道路噪声主动控制系统仿真模型，使用采集到的冲击噪声信号和加速度信号进行了仿真分析。最后，使用选取的4个加速度信号和1个扬声器，控制驾驶员处的道路噪声，进行了道路冲击噪声主动控制试验，验证了方法的有效性。与原有算法相比，该算法的稳定性和降噪效果得到了较大的提升。     

信号叠加技术在心室晚电位信号检测中的应用

心室晚电位（ＶＬＰ）怀心肌死及室性心动过速是密切相关的，所以ＶＬＰ的无创检测可为临床诊断提供有效的依据，但ＶＬＰ信号常被噪声所淹没，直接检测非常困难，利用信号叠加技术处理ＥＣＧ信号，可有效消除噪声，使ＶＬＰ信号能准确地检出，在信号叠加过程中，同步参考点位置的确定至关重要本文介绍了利用截取固定度确定同步参考点的方法。     

海洋激光雷达系统接收信号噪声的相空间分析

通过对海洋激光雷达信号噪声的相空间分析，并通过与确定信号、随机信号、混沌信号相空间的比较，首次发现了海洋激光雷达接收信号噪声与混沌信号相似的相轨迹特征，初步揭示了海洋激光雷达信号噪声的混沌特性．     

有色噪声中随机相位信号的检测研究

提出了一种在有色噪声背景下检测随机相位信号的一种新方法．将有色噪声背景下含噪观测量的功率谱化为白噪声背景下的含噪观测量的功率谱,从而构造出与原被测信号具有相同频率的白噪声背景下的信号,然后利用现有的白噪声背景下的方法进行随机相位信号的检测．     

非高斯非平稳噪声背景下杜芬系统动力学仿真研究

研究非高斯非平稳噪声背景下非线性系统在微弱周期信号摄动下的混沌动力学行为,仿真过程证明被噪声污染的微弱周期信号使混沌系统的动力学行为变化很小;非高斯非平稳噪声对周期运动的影响较为明显。研究了微弱周期信号和非高斯非平稳噪声信号联合摄动下的混沌运动特征。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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