分数阶混沌系统同结构与异结构广义同步

基于分数阶拉普拉斯变换理论,提出设计合适的新型非线性反馈控制器,分别实现分数阶混沌系统的同结构广义同步和异结构广义同步.以分数阶Liu混沌系统和分数阶Lu混沌系统为例进行数值仿真,仿真结果表明了该方法的有效性.该方法灵活且适用范围广,具有潜在的应用前景.

     

不同维不同阶的分数阶混沌系统同步及仿真

分数阶混沌系统同步在安全保密通信等领域有着重要的应用价值和研究意义.对不同维不同阶的分数阶混沌系统之间的广义同步,根据主动控制和分数阶系统稳定性理论设计控制器实现同步.先将两个分数阶混沌系统分解为线性和非线性部分之和,用主动控制构造同步误差方程,然后利用分数阶线性时不变系统稳定性理论设计控制器,实现不同维不同阶分数阶混沌系统之间的广义同步,再用分数阶微分的Caputo定义和分数阶微分方程的预测校正数值解法进行数值仿真,实现三维Chen系统和四维超Lorenz系统间的广义同步.仿真结果表明了提出方法的有效性.     

两个分数阶混沌系统的广义投影同步及电路实现

研究了分数阶混沌系统的广义投影同步及电路实现。基于非线性观测器,提出了用于实现分数阶混沌系统的广义投影同步的一般方法。并建立了相关的数学模型,证明结果的有效性。运用了Matlab进行数字仿真进一步表明该方法的可行性。最后,利用Multisim设计模拟电路,其结果与Matlab的仿真结果吻合,为分数阶混沌系统同步今后的实际运用打下基础。     

两个不同分数阶混沌系统的广义投影同步

针对不同的分数阶混沌系统的同步问题,基于分数阶微积分理论和分数阶线性系统稳定性理论,设计了相应的控制器,实现了分数阶Chen系统和Lorenz系统之间的广义投影同步,数值仿真的结果验证了该控制方法的有效性和可行性。     

不同阶分数阶混沌系统的同步与参数辨识

针对不确定分数阶混沌系统的同步和参数辨识问题,提出一种新的方法,即用不同阶分数阶系统来同步和参数辨识.利用主动控制和预控制量方法,基于分数阶混沌系统稳定性理论和自适应控制理论,设计控制器,实现不同阶分数阶混沌系统之间的同步和参数辨识.理论和仿真结果实现了不同阶Chen 系统间的同步和辨识,表明了该方法的有效性.     

分数阶异结构超混沌系统完全同步与反相同步控制

以分数阶Lü混沌系统和分数阶Chen超混沌系统为例,研究了维数不同、分数阶次不相等的异结构的混沌系统和超混沌系统的完全同步和反相同步.首先,基于分数阶系统稳定性理论和非线性动力学理论,构造出相应的非线性控制器,实现了两个维数不同,分数阶次不相等异结构混沌系统与超混沌系统的完全同步和反相同步;其次,基于分数阶稳定性理论,对上述两类同步给出了严格的数学证明;最后,借助于预估-校正算法,利用数值模拟验证了所提方法的有效性.     

分数阶混沌系统广义混合投影同步与参数辨识

研究两个不同的分数阶混沌系统的广义混合投影同步(GHPS)及参数辨识.基于分数阶稳定性理论,运用自适应控制法与混合反馈控制法,设计混合反馈控制器及参数自适应控制律.控制器能够根据误差状态自动调节反馈增益系数,能有效提高同步效率,最终实现了两个不同的分数阶混沌系统的广义混合投影同步并估计出不确定参数,并给出严格数学证明.最后通过预估校正算法进行了数值仿真,结果表明:由驱动系统与响应系统构建的误差系统将在一定时间内稳定于零点,验证了该方法的有效性和可行性.     

基于分数阶积分器的分数阶混沌系统状态观测器同步研究

提出了一种基于分数阶积分器的分数阶混沌系统状态观测器同步算法。通过引入一个新的变量,该变量是将驱动系统的输出信号与传输信道中干扰的和进行分数阶积分处理,然后再作为输入信号加到观测系统中,以便实现分数阶混沌系统的状态观测系统同步。然后利用Lyapunov稳定性理论和线性矩阵不等式证明了该方法的正确性。将该同步方法应用于分数阶Chen混沌系统,得出了同步误差曲线,仿真结果表明了该同步方法的有效性,最终实现了分数阶混沌系统的状态观测器同步。     

一类分数阶(超)混沌系统异结构同步及仿真

针对一类分数阶(超)混沌系统的异结构同步问题,根据分数阶动力系统稳定性理论,结合反馈控制和主动控制方法提出了一种新的分数阶(超)混沌系统异结构同步方法。方法不仅不需要计算复杂的条件Lyapunov指数,而且保留了响应系统的非线性项。在数值研究过程中,可直接用时域进行数值计算,而不必进行时域与复频域转换。仿真结果表明:所设计的控制策略简单、易于实现,而且没有强加在系统上的限制条件,因此应用范围较宽。理论分析及仿真结果证明该方法的有效性。     

一类混沌系统的分数阶广义同步

针对一类参数未知的混沌系统,基于分数阶微积分和Lyapunov稳定性理论,设计出了一族分数阶广义同步控制器,此族控制器可通过选择不同分数阶次得到不同的控制效果,并且都能保证闭环混沌系统达到渐近广义同步.数值试验验证了此方法的有效性。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.