嵌入分层聚类的小波零树图像编码

该文研究了小波系数的一类新的统计特性－－分层聚类特性，为了利用这种特性，文章分析了这些分层聚类的结构关系，并结合已有小波零树技术提出了一个嵌入分层聚类零树小波图像压缩编码算法，这个新算法利用形态学算子来聚类优化子带内重要系数编码，同时使用小波零树来实现对子带间小波系数相似衰减特性的利用，提高对不重要小波系数的编码效率，因此，新算法有效地克服了单纯使用零树或单纯使用形态学聚类技术所存在的不足，实验结果证实：该文所提出的编码器性能相对于EZW编码器有明显的提高，其性能可以与SPIHT编码器和MRWD编码器相媲美，该文所提出的编码器不仅具有渐进传输和CBR应用所需的嵌入特性，同时也具有极低的算法复杂度，稍加改动还可以支持多分辨编／解码。     

图像编码中的重要区域相关性研究及应用

在图像处理中,小波变换所具有的空频局部性,使得图像的能量重新分布。从函数正交分解的角度,小波分解相当于把图像分成一组正交基的坐标。由于这些坐标具有按不同频带所表现出的能量集中的性能,所以关于形态学的一些编码方法在基于小波分析的图像压缩中得到了很好的应用。因此,可以说小波变换在图像中的成功应用,主要归功于关于数据即小波系数系数和表示的重要性的认识。作者在文中提出了基于小波系数有效组织和表示的重要区域相关性编码（SRC）,合理利用各子带间重要小波系数的相关性,通过聚类生成与聚类编码,在良好视觉效果与较高PSNR下,实现了图像较大倍数的压缩。     

基于模糊聚类的小波变换图像去噪算法改进

介绍一种改进的较优的基于模糊聚类的小波变换图像去噪算法.首先分析了模糊C均值聚类算法中加权指数m的重要性,采用基于模糊决策的方法,分别构造模糊目标和模糊约束,由模糊目标和模糊约束的交集来共同确定最优的加权指数m以获取较为理想的聚类分类结果.再利用该种加权模糊聚类算法把小波系数划分成包含信号与只包含噪声的小波系数两类,将只包含噪声的小波系数置为零,将包含信号的小波系数利用软阈值法进行收缩,最后对处理后的系数根据M带小波变换的局部时频分析能力及其良好的信噪分离能力进行M带小波变换,得到去噪效果较好的图像.     

最小二乘拟合与形态学膨胀的图像数率可分级编码算法

本文提出一种基于最小二乘的线性拟合和形态学膨胀操作的小波域图像数率可分级编码算法,该算法利用图像小波变换子带中的零树结构系数间的对应关系,利用最小二乘线性拟合方法通过对父亲系数和间接后代系数的线性拟合确定直接后代的重要系数。同时通过对重要系数进行数学形态学的膨胀操作,形成重要系数的聚簇,从而降低重要系数位置的同步信息。来提高图像的编码效率。实验结果表明,在低码率下,解码后的图像较EZW和MRWD具有更好的峰值信噪比。     

基于方向图及小波系数重要连接的指纹图像压缩算法

提出了一种在SLCCA算法基础上结合指纹方向图的指纹压缩算法。首先将指纹图像按纹理信息进行分块,然后根据各指纹图像方向块的方向,确定不同的结构元素对小波图像各子带中的重要系数进行数学形态学的膨胀操作来提取各子带中的重要系数簇。再根据不同予带间重要系数簇中父系数与子系数间的重要系数分布建立重要连接。算法不仅充分考虑了小波分解图像不同子带内的重要系数分布的聚类特性,同时也充分考虑了各子带间的重要系数分布的自相似性。实验结果证实该算法不仅比WSQ、EZW、SPHIT、MRWD、SLCCA算法具有更好的性能。而并且可与最新的有损压缩算法JPEG2000相媲美。同时,编解码的速度较快。     

一种图像序列小波系数的分形编码算法

提出了一种使用分形映射实现图像小波子带系数编码的新的方案。利用小波各子带系数之间的相似性,定义了一种前后小波带内的父子节点间的映射结构关系,从而对Ｒａｎｇｅ块进行分形匹配。编码无须搜索Ｄｏｍａｉｎ块,解码也无须迭代;并且对已编码的码流,采用算术编码以获得进一步的压缩。对图像序列,则采用条件补充（Ｃｏｎｄｉｔｉｏｎａｌ Ｒｅｐｌｅｎｉｓｈｍｅｎｔ）进行帧间编码,以减少算法运算量,增加实时性。实验结果     

基于小波子带系数预测的深度图像编码

随着3D视频技术的再度兴起,基于深度图像的3D视频数据表示格式得到了广泛的应用,因此针对深度图像的编码算法已成为当前研究的热点课题。利用小波变换后子带系数的分布统计特征,提出了一种不同于以往的基于小波变换的深度图像编码方案。该方案对小波量化系数进行统计分析,利用子带间小波系数的相关性,对小波变换后各个子带的小波系数进行预测。在同一层小波子带间,利用对角子带系数分别对水平和垂直方向的子带系数进行预测;在相邻层间,被预测的系数利用上一层相应的4个低频子带系数进行预测。最终,将原子带系数与预测系数的残差进行算术编码。实验结果表明,本方案在保证图像质量的同时能够有效地减少深度图像编码所需的比特数,最大可节省18.4%的码率。     

基于小波-Contourlet变换的图像压缩算法

利用小波-Contourlet变换对图像分解具有多尺度和多方向性的特点,提出一种结合小波-Contourlet变换和无链表集合分裂嵌入块编码的图像压缩算法.小波-Contourlet通过方向滤波器组把小波分解的高频予带进一步分解为多个方向子带,从而更稀疏地表示图像的边缘和纹理.无链表集合分裂嵌入块算法充分利用系数子带内的相关性,具有复杂度低、编码效率高的优点.实验结果表明,与基于小波变换的SPIHT算法和SPECK算法相比,新算法对纹理丰富的图像有很好的压缩效果和视觉效果.     

一种基于小波零树编码和K-mean聚类的图像压缩的实现

针对在低比特率时图像存在严重的方块效应等不足,本文提出了一种基于小波零树编码和K-mean聚类的图像压缩算法。其中基于小波零树的图像编码克服了图像JPEG标准压缩算法在统计值较少时的方块效应现象,通过K-mean聚类算法可以改善小波零树编码算法中没有充分考虑到小波系数同一子带中相邻元素之间相关性的缺陷。实验结果表明,此改进的图像编码算法具有较好的信噪比和压缩比。     

基于小波系数特性的低比特率图像压缩编码算法

以层树分集（SPIHT）编码方案为基础,结合最低频子带系数分布特点与高频子带系数相关性,提出了一种新的低比特率小波域图像压缩算法.该算法首先对原始图像进行小波变换;然后对最低频子带系数进行优化处理,并自适应确定高频子带系数扫描次序;最后利用SPIHT编码思想完成图像的压缩.仿真实验结果表明,文中算法是一种高效的图像压缩编码方法,其压缩效果明显优于SPIHT编码方案（特别是低比特率下）.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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