基于改进轮廓波变换的SAR图像增强

针对轮廓波变换（contourlet transform）中进行拉普拉斯金字塔分解时,所得的带通图像在奇异性点附近产生振荡,影响图像去噪的效果,提出一种改进的轮廓波变换。通过改进拉普拉斯金字塔分解,可消除轮廓波变换带通图像边缘附近的震荡。提出了基于改进轮廓波变换的SAR图像增强算法。实验结果表明,该算法在有效抑制SAR图像噪声的同时,较好地保持了图像边缘细节。     

基于剪切波和改进P-M扩散的图像去噪

针对多尺度几何分析方法去噪时产生的伪Gibbs效应和各向异性扩散模型产生的阶梯效应,提出一种基于剪切波的改进各向异性扩散图像去噪方法。首先对噪声图像进行剪切波变换得到不同尺度的系数矩阵,然后利用改进的各向异性扩散方程对变换后的系数进行处理,实现建立在对图像精细分析基础上的各向异性扩散模型。实验结果表明,该方法能较好地抑制噪声和保持边缘,同时有效地抑制伪Gibbs效应,取得良好的视觉效果。     

基于贝叶斯估计的改进Contourlet变换的SAR图像滤波

针对小波变换和轮廓波变换在合成孔径雷达(Synthetic aperture radar, SAR)图像中去噪应用的不足,结合小波变换和轮廓波变换的优点,将小波变换与轮廓波变换相结合,提出一种改进轮廓波变换方法。首先将待处理图像进行小波变换,然后对低频子带图像进行重建,得到一个细节子带图像,然后使用方向滤波器组对其进行多方向划分。再采用贝叶斯最大后验概率估计对划分后的方向子带信号进行估计。实验结果表明此方法在抑制图像斑点噪声的同时,很好的保持了均匀区域的辐射特性,保持了图像中的边缘以及细小纹理,且没有人为畸变。此外算法的高频子带图像含有更为丰富的纹理,对于边缘特征的提取非常有益。     

一种改进的非下采样轮廓波变换图像去噪算法

优化图像去噪问题,在非下采样轮廓波变换图像去噪中,收缩阈值的确定仅依赖变换子带系数的幅值,使得过多图像系数和噪声系数一并去除,导致滤波图像模糊。从检测变换子带几何结构出发,引入自蛇模型对子带系数作几何结构检测并抑制噪声后,估计双阈值将子带系数划分为三类并作不同处理,实现对噪声系数的去除和对图像系数的保护。实验结果表明,相对现有典型算法,改进算法获得的峰值信噪比提高了0.1-0.9dB,图像系数被更好识别和保留,滤波图像中边缘与区域细节损失减少,提高去噪效果,保留图像的有效信息。     

非负矩阵分解和新轮廓波变换的图像融合

为提高融合图像保留源图像的信息量和边缘特征,提出了非负矩阵分解和新轮廓波变换的图像融合算法。以具有尖锐频率局部化特征的新轮廓波对循环平移后的源图像进行分解;运用非负矩阵分解实现低通子带融合,采用能量方差测度函数和匹配度函数实现带通子带融合;对各子带信号重构并逆循环平移,得到融合图像。实验结果分析表明,该方法保留了更多的信息量和边缘细节特征,应用效果较好。     

基于改进轮廓波变换的图像去噪算法

在轮廓波变换中进行拉普拉斯金字塔分解时,所得的带通图像在奇异性点附近产生振荡,影响了图像去噪的效果。针对该问题,提出一种改进的拉普拉斯金字塔分解,可消除边缘附近的震荡。利用改进的拉普拉斯金字塔实现轮廓波变换,并对图像进行自适应去噪。实验结果表明,该算法所得的峰值信噪比较轮廓波变换自适应去噪算法有显著提高,且视觉效果有较大改善。     

各向异性扩散的遥感图像边缘增强方法

为解决遥感图像边缘增强过程中辨识弱边缘和噪声的问题,提出一种改进的模糊各向异性边缘增强方法。根据非下采样轮廓波变换系数分布特征,获得像素几何结构信息;并基于各像素在不同子带的系数分布特征和噪声方差,分析其均值和最大值的模糊隶属度;利用模糊推理计算扩散系数,更好地控制各向异性扩散过程。实验结果显示,该方法具有更好的边缘增强和抑噪性能,能有效地辨识弱边缘和降低时间复杂度。     

圆对称轮廓波变换的构造

提出了具有类似于视皮层变换频带划分的圆对称轮廓波变换.在该变换中,圆对称滤波器组将图像分解为多个不同分辨率的细节子带和一个低频子带,方向滤波器组再将各细节子带分解为方向子带.文中利用遗传算法设计满足重构要求的圆对称滤波器组,应用伯恩斯坦多项式设计的映射函数将9/7双正交滤波器组映射为扇形滤波器组.利用自适应阈值法对Lena图像去噪的实验结果表明,两种圆对称轮廓波变换（CSCT1和CSCT2）的去噪性能与轮廓波变换相比有显著提高.     

图像有损压缩预处理的各向异性扩散新方案

结合小波变换,提出了图像有损压缩预处理的各向异性扩散方案。各向异性扩散在图像平滑中,其不但能够较好地抑制噪声,而且能够很好地保留图像原有的边缘和纹理特征,而小波变换又具有人类的视觉特性。该方案先对图像作小波变换,再根据各子图像的特点,用不同的各向异性扩散方法处理子图,最后压缩重构图像。实验表明,对有损压缩来讲,与已有的方法比较,该方案具有更好的解码质量和更高的压缩比。     

基于平稳小波域的各向异性扩散图像去噪方法

针对传统的各向异性扩散去噪方法存在的导致图像细节丢失的问题,提出了一种基于平稳小波域的各向异性扩散图像去噪方法。该方法根据平稳小波变换的特性,通过在高频和低频子带上选用不同的梯度门限进行各向异性扩散,然后进行重构得到去噪后的结果图像。实验结果表明,该方法在有效去除噪声的同时,图像细节保留较好,去噪后的图像具有更好的质量。     

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.     

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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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