模块神经元网络中耦合时滞诱导的簇同步转迁

利用Courbage-Nekorkin-Vdovin神经元构建含有耦合时滞的模块神经元网络模型,通过数值模拟研究了耦合强度及耦合时滞对模块神经元网络簇同步放电特性的影响.研究结果表明,适当大的耦合强度可以诱导模块神经元网络达到簇同步.同时,研究发现耦合时滞可以诱导模块神经元网络出现簇同步转迁,且当时滞大小约为网络中所有神经元平均振荡周期的整数倍数时,模块神经元网络的簇同步现象能够间歇性出现.此外,研究结果表明时滞诱导的簇同步转迁对子网络内的耦合强度、子网络间的连接概率具有鲁棒性.     

前馈型神经元网络中的放电频率传递分析

本文建立了一个基于Hodgkin-Huxley神经元的前馈神经元网络模型,研究了平均放电频率在前馈神经元网络中的传递情况。研究结果显示,适当的层间连接概率与输人噪声强度能够提髙前馈神经元网络的同步效率,进而增强网络稳定传递放电频率的性能。此外,通过引入并调节突触时滞,发现适当的时滞对神经元耦合系统的完全同步和前馈神经元网络内信息传输有明显的促进作用。     

异质性和时滞作用下神经元网络的共振动力学

利用参数互异的Fitzhugh-Nagumo神经元构建了含耦合时滞的无标度神经元网络模型,通过数值模拟的方法,提出研究参数异质性和耦合时滞影响下神经元网络的共振动力学.结果发现,当耦合项中不含时滞时,适中的参数异质性能够使得神经元网络对外界弱周期信号的响应达到最优,即适中的参数异质性能够诱导神经元网络的共振响应,而且异质性诱导共振对耦合强度具有鲁棒性.更重要的是,耦合时滞对参数异质性作用下神经元网络的共振特性也有着显著性影响.当时滞约为信号周期的整数倍时,神经元网络能够周期性地出现共振现象,即适当的耦合时滞能够诱导神经元网络的多重共振,而且这种现象在异质性参数的适当范围内都能明显出现.     

ML神经元的放电模式及时滞对神经元同步的影响

研究了单个ML神经元的放电模式及其动力学特征．通过快慢动力学分析得出随着参数的变化,神经元可以呈现出静息态、簇放电及峰放电等多种放电模式．本文同时研究了耦合强度和时滞对突触耦合的两个神经元同步的影响．在无时滞时,随着耦合强度的增大,耦合神经元的在相同步得到增强．而在某段时滞范围内,神经元在比较小的耦合强度下就能达到同步,这说明有效的时滞能够增强同步．此外,时滞只能在某些耦合强度下才对耦合系统的同步起作用．     

含时滞和Ih流的神经元的同步放电行为

本文研究了时滞和超极化激活的阳离子流Ih对抑制耦合的水蛭神经元的同步放电行为的调控.通过数值仿真揭示了时滞、耦合强度和Ih流都能诱发丰富的同步转迁行为,如从同步的周期-6簇放电到同步的周期-1簇放电.借助ISI分岔和快慢变量分离方法获得了Ih流诱导同步转迁行为的动力学原因.研究结果表明,时滞和Ih流都是影响水蛭神经元同步行为的重要因素.     

非线性时滞反馈实现离散神经元网络的去同步化

采用非线性时滞反馈实现离散神经元网络的去同步化控制．对于由映射神经元模型构建的神经网络，调节神经元之间的连接强度可以实现网络的混沌簇放电同步．在神经元的快变量中施加非线性时滞反馈信号可以实现网络的完全去同步化，且不改变神经元本身的放电特性．与线性时滞反馈相比，非线性时滞反馈能够实现强连接神经网络的去同步化，且对于参数的变化具有鲁棒性．     

考虑树突整合效应的神经元网络的放电和同步特性

生物神经网络的同步被认为在大脑神经信息的处理过程中发挥了重要作用.本文在Hodgkin-Huxley(HH)神经元网络模型中考虑树突整合效应,得到修正后的DHH(Dendritic-integration-rule-based HH)神经元网络模型,研究了网络的放电和同步特性.首先以三个抑制性神经元构成的耦合系统为例,发现树突整合效应的加入提高了神经元的放电阈值;然后分别建立全局耦合的抑制性和兴奋性神经元网络,发现大的耦合强度能够诱导抑制性和兴奋性神经元网络达到几乎完全同步的状态,并且对神经元的放电幅值有较大的影响;更有趣的是,当树突整合系数为某一值时,抑制性神经元网络的同步达到最高,而兴奋性神经网络的同步达到最低.     

对称电耦合连接方式下的多尺度同步行为和转迁过程

本文研究了改进的ML神经元模型在环式和链式两种对称连接结构下的多尺度同步转迁过程.通过定义峰相位、簇相位、网络的平均峰频率差和平均簇频率差,发现随着耦合强度的增加,耦合神经元从互不相关到簇同步再到峰同步过渡,最后达到几乎完全同步.簇同步和峰同步属于相位同步的两种节律类型,对应慢时间尺度的簇同步通常先于对应快时间尺度的峰...     

局部耦合的双层忆阻神经元网络的嵌合态和同步

嵌合态被发现存在于神经系统并且可能在神经元节律、大脑的睡眠和记忆等诸多神经过程中发挥重要作用.本文考虑神经元交互中的电磁感应现象,建立了以Hindmarsh Rose神经元为节点的局部耦合的双层忆阻神经元网络,研究其嵌合态时空动力学模式及产生机理.结果发现,改变层内、层间突触耦合强度会使网络产生移动和不完美移动嵌合态等多种类型的嵌合模式,其中不完美移动嵌合态中不相干的区域会扩展到网络的相干域.特别地,在特定耦合强度下,存在一种新的嵌合态活动模式,即一部分神经元处于嵌合态,另一部分神经元处于移动嵌合态.考虑神经元突触的忆阻特性,发现忆阻参数的增加能够使处于嵌合态的神经元网络转变为同步态,且耦合强度越大,达到同步态所需要的忆阻参数值越小.进一步探究双层网络的同步性,发现层间耦合强度和忆阻参数的增大有助于网络达到更好的同步.研究结果表明神经元之间的相互作用可以激发双层神经元网络产生多种嵌合态模式,电磁感应可以促进网络由嵌合态向同步态转迁,这些结果有助于理解人脑中复杂的神经放电过程和信息处理机制,并为可能的类脑装置应用提供参考.     

具有时滞的耦合Hindmarsh-Rose神经元系统的放电模式

基于在无时滞的情况下,非全同的HindmarshRose耦合神经元达到几乎完全同步的放电模式,通过数值模拟的方法,研究了时滞对耦合HindmarshRose神经元同步后放电模式的影响.结果表明时滞使得神经元的放电模式发生改变,同时时滞的增加能够诱导簇中的峰逐渐地减小或消失.这一研究将有助于我们更深入地了解时滞对耦合神经元系统行为的影响.     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。