一种基于新的混沌系统的彩色图像加密算法

为克服现有的图像加密算法由于使用一维混沌系统所导致的安全性低的缺陷,基于新的三维混沌系统,本文提出了一种彩色图像加密算法。该算法首先利用混沌序列对图像的像素位置进行置乱处理,打乱彩色图像各颜色分量的像素位置;在此基础上,对置乱后的彩色图像进行像素值的扩散处理,通过使用混沌序列和异或、取余运算,改变置乱图像每个像素点的三基色像素值,从而得到最终加密图像。实验结果表明,本文所提出的彩色图像加密算法具有密钥空间大、敏感性强和安全性高等特点。     

基于改进的CAT置乱与Henon_Kent混沌系统的彩色图像自适应加密算法

为了解决彩色图像加密算法中密钥与明文图像不关联的安全性不足以及CAT映射成立条件的问题,提出一种基于改进的CAT置乱系统与Henon_Kent混沌扩散系统的彩色图像自适应加密算法。该算法首先利用明文图像特征信息生成密钥;然后通过改进的CAT置乱系统对图像进行像素位置的三维置乱,再将Henon_Kent混沌系统所产生的三个混沌序列分别对RGB三个通道的像素灰度值进行扩散;重复以上两个步骤,以密文图像的信息熵大于7.99为结束条件。仿真表明该算法能够抵抗现有的攻击方法,具有较强的加密性能。     

基于矩阵变换的彩色图像加密算法

研究了矩阵变换的性质,找到一种新的SCAN遍历矩阵,对彩色图像各分量进行像素位置置乱,结合彩色图像结构特点,利用彩色图像每个像素的RGB分量构成三维列向量,并将其作为输入分量,经过矩阵变换,改变其像素值的大小,得到加密矩阵.试验结果表明,加密图像具有类随机性,直方图接近于均匀分布,算法具有很强的密钥敏感性.     

混沌映射和流密码结合的图像加密算法仿真

为了有效改进彩色图像加密的效果和安全性,在对采用混沌映射的图像加密算法研究的基础上,提出一种结合混沌映射和流密码的彩色图像加密算法。加密过程采用置乱-扩散结构:在置乱阶段首先根据输入图像初始化Kent混沌系统,再利用Kent混沌系统生成ZUC-256流密码算法的初始密钥和初始向量,ZUC-256算法随后生成随机序列对彩色图像进行R、G、B三轮像素值置乱。在扩散阶段同时使用Kent混沌系统和ZUC-256流密码算法生成的随机序列对输入图像的像素值进行扩散。仿真结果显示,提出的算法具有加密算法简单、密钥空间大等特点,能较好地抵抗差分分析攻击、统计特性攻击。     

基于混沌系统的彩色图像加密新方案

提出了一种新的基于三维Chen系统的彩色图像加密算法。将三维空间的彩色图像转换成二维的灰度图像,利用混沌系统生成的混沌序列对二维灰度矩形图分别进行行置乱及列置乱;对置乱后的图像进行加密;按折叠算法对加密后的图像进行折叠处理。仿真结果及安全性分析表明,该加密算法是在二维空间对图像像素进行处理的,相对于三维加密算法而言,降低了算法的计算强度和空间需求,从而减少了运行时间,加快了加密速度;置乱时实现了不同层次（R,G,B）亮度值的完全混合,加密效果好,安全性更高。     

基于新混沌与矩阵卷积运算的彩色图像加密算法

针对彩色图像加密过程中出现的强相关性和高冗余问题,提出基于云模型的Fibonacci混沌系统与矩阵卷积运算的彩色图像加密算法。首先对彩色图像的R、G、B分量拼接图像像素点坐标变换置乱;然后将混沌序列值作为卷积核的输入值与像素值进行矩阵卷积运算,实现像素值置换;再与云模型Fibonacci混沌序列及前相邻像素值进行正反双向2次异或操作生成加密图像。实验分析表明,加密后的图像直方图更加平滑,像素分布均匀,图像相邻像素相关性低,加密图像RGB分量平均水平、垂直和对角相关系数分别为-0.0010,0.0016和0.0031,能够抵抗差分攻击、明文攻击、噪声攻击和剪切攻击等攻击实验,提出的新加密算法具有加密安全性高、抗干扰性高、鲁棒性强等特点。     

提取明文信息耦合多混沌像素混乱的彩图 RGB 分量同步无损加密算法

针对当前的彩色图像加密方案都是将 R、G、B 三基色的像素分离来单独进行加密,且生成的混沌序列不依赖于明文信息,导致密文随机性和抗攻击性较差等不足,提出了提取明文信息耦合多混沌像素混乱的彩图RGB 同步加密算法。首先,将图像 RGB 三基色的像素进行分离、二值化与矢量化处理,得到 RGB 三个矢量;重组这些矢量,得到 R、G、B 各像素均彼此依赖的置乱矩阵;然后,通过提取明文图像信息来控制四个超混沌系统的迭代,得到与明文相关的随机序列,对置乱矩阵完成列、行扩散。仿真结果表明,与其他彩图加密机制相比,加密系统的安全性更高,且密钥空间更大,密钥敏感性强。     

复合级联混沌的彩色图像加密算法

分析了目前基于混沌系统的彩色图像加密算法,其中发现在混沌彩色图像加密过程中安全性方面的不完善,并在此基础上提出了一种新型的基于级联混沌的多重像素置乱彩色图像加密算法。该算法采用了Kent-Logistic的级联混沌与Henon离散混沌的复合系统,同时结合Arnold映射和像素排列切割的多重像素置乱方法,使得图像像素值和像素位置全盘置乱扩散,从而达到明文图像信息完全隐藏的密文效果。仿真实验表明,该算法不仅能有效抵抗选择明文（密文）攻击、统计特性分析、差分攻击,而且还具有加密效果好、密钥空间大等优点。     

基于多维混沌系统组合的图像加密新算法

提出了基于多维混沌系统同时对图像像素位置置乱和像素值加密的新算法。利用广义Arnold映射对图像像素位置进行置乱；利用三维Liu混沌系统产生的混沌序列得到整数密钥序列，对置乱图像像素值逐个进行加密。实验表明这种加密算法具有密钥空间大、安全性高的优越性，加密图像像素值具有类随机均匀分布特性，相邻像素具有零相关特性。     

基于混沌系统和动态DNA编码与运算的彩色图像加密算法

现有结合混沌系统和DNA计算的图像加密算法因DNA编码规则和运算规则单一、加密结构安全性低,导致算法易被破解。为此,提出一种结合Intertwining Logistic映射和动态DNA编码与运算的彩色图像加密算法。该算法包括置乱阶段和扩散阶段,在置乱阶段,利用模拟退火算法构造的置乱序列分别对彩色图像信道进行行和列置乱,得到置乱信道。在扩散阶段,先根据随机序列值动态选择各置乱信道每个像素点的DNA编码规则及运算规则,然后结合密文反馈机制进行DNA加密计算。实验结果表明,该算法具有良好的抗攻击能力及加密效果。     

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