一种基于4叉树的分类矢量量化算法

提出了一种基于４叉树的分类矢量量化算法。它充分利用了图象的局部统计特性和人眼的视觉特性，综合了分类矢量量化、方块编码、抽样／内插等多种技术的优点。在提高了压缩效率的同时，又克服了其矢量量化算法中常见的边缘细节模糊的缺陷。实验表明，对于静止灰度图象，在码率低于０．２５ｂｐｐ时，仍具有令人满意的主观视觉质量。较ＪＰＥＧ算法，同等码率下，峰－峰信噪比提高２ｄＢ以上。     

用于PACS系统的医学图象量化编码的算法

图象压缩是PACS系统的重要研究部分。作者研究了二维图象小波分解后系数的统计分布与拉普斯分布有很好的一致性；同时，由于不同幅度的小波系数在图象重构中权重的不同，在系数压缩编码时对不同权重的系数采用不同的压缩精度。由此，作者提出了一种适用于PACS系统的图象量化编码算法，该算法以各小波子带图象小波系数的重要统计特征-样本标准差为量化阈值选择依据，精确编码图象重构中权重较大的系数，还利用了人眼的频率视觉特性。实验表明，本算法具有计算简单、不同编码精度时被量化系数可预见的特点，同时在保证图象质量的基础上可获得较高压缩比。     

立体压缩图像的客观质量评价方法

针对立体图像的客观质量评价问题,提出了一种适合于立体压缩图像的质量评价方法．该方法基于平面图像的人类视觉系统评价模型,考虑了人类视觉系统的多通道特性和对比度敏感度特性,使用Contourlet变换实现多通道分解,将立体图像对的差值信号进行评价．实验结果表明,该方法得到的质量评价结果符合人眼视觉特性,与主观质量评价方法的一致性较好,能够客观反映压缩立体图像的质量．     

基于MATLAB的小波分析方法与图象编码

主要介绍了用基于MATLAB的小波分析方法进行图象编码的原理,并对小波分解和重构及图象压缩和解压缩的必然关系进行了详细阐述.同时给出了较为具体的小波分解与重构实验设计报告.实验表明:对图象数据进行小波分解与重构,实际取得了图象压缩与压缩的效果.     

基于MATLAB的小波分析方法与图象编码

主要介绍了用基于MATLAB的小波分析方法进行图象编码的原理,并对小波分解和重构及图象压缩和解压缩的必然关系进行了详细阐述.同时给出了较为具体的小波分解与重构实验设计报告.实验表明对图象数据进行小波分解与重构,实际取得了图象压缩与压缩的效果.     

电视视频噪声功率与加权压缩分析

本文对电视接收机的视频通道噪声功率互换前后进行了讨论。根据ＣＣＩＲ推荐的加权网络，采用加权压缩后对图象质量的实际受损情况进行修正，使被测结果与主观评价一致。     

一种改进的BP网络图象压缩方法

本文提出了一种改进的ＢＰ网络图象压缩方法．该方法对输入图象矢量进行分类，不同类别的图象矢量分别由不同的ＢＰ网络来实现压缩和恢复．因为同一类别图象矢量间离散度较小，所以可降低ＢＰ网络的映射复杂度，从而达到改善图象质量的目的．实验结果表明，这种改进能有效提高恢复图象的信噪比和视觉质量，对数据压缩比影响很小．     

一种基于小波分解与分形编码混合的图象压缩方法

利用双正交小波特性和小波塔式分解数据的多分辨特性、分形的IFS编码高效特性,提出了一种基于小波分解和分形编码压缩图像数据的方法。该方法先用一个小波将图象进行小波变换（分解）;在频域上,对不同频域层用不同的分块方法和比特率分配方法进行分形编码。根据实际需要和视觉特性来控制压缩比。重构时先在频域进行分形重构解,然后再用另外一个正交小波重建原图象。     

人眼动态视觉特性分析

人眼作为电视系统的接收终端,其视沉特性直接决定着对电视系统的特性要求;也是对电视图象信号进行频带压缩处理的基础,本文基于人眼的视觉特性,提出了人眼视觉响应模型,分析了人眼动态视觉特性,分析表明,由于视觉残留的影响,人眼对活动图象的空间分辨力将降低,而对时变图象则表现为对层次的分辨力下降,其结果都降低了对单幅图象的有效息信量,从而为对视频图象信号的频带压缩提供了可能。     

1.0b/pel的自适应DPCM图象编码

本文利用人眼的视觉特性提出了改进DPCM(差分脉码调制)图象编码的两种方法:一种是采用膈行隔象素取样和优化修正插值的自适应DPCM,可使图象的比特率由8b/pel压缩到1.0～1.5b/pel,量化信噪比可达39dB以上;另一种是采用方块编码的自适应DPCM,可在同样图象质量的条件下,把此特率进一步压缩到0.8～1.0b/pel。这样,基本上解决了DPCM编码中压缩比提高与图象质量下降的矛盾。     

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