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脑电产生源三维空间分布的仿真研究 总被引:3,自引:0,他引:3
对于脑电信号源的分布模型,在基于加权广义逆矩阵的最小范数解的框架下,进行了源分布图象的计算机仿真计算,主要包括两部分内容:通过求解脑电正问题的边界元算法获取导联场矩阵;以脑电生理学上的特性,即源活动的高度协同性、聚集性及稀疏性为先验前提,借鉴LORETA算法中有关拉普拉斯平滑算子,以及FOCUSS算法中有关重加权的竞争机制等,通过分阶段地构造加权矩阵的方法逐步对逆解做出约束,实现具有较高分辨率的脑内各处电活动源的强度与方向的三维图象重建。计算机仿真研究结果证实了此方法的可行性。 相似文献
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利用LS—SVM模块化决策系统求解EEG源参数 总被引:1,自引:1,他引:0
给定头皮脑电位的分布推算脑内电活动的源是脑电研究的一个重要的方面.研究涉及到信息科学、电磁场计算及生物医学工程等多个学科领域,其研究成果在神经疾病诊断、探索人的感觉和认知过程等方面具有蕈要意义.基于最小二乘支持向最机(LS-SVM)算法建立模块化决策系统,首先对脑电数据进行分类,然后依据分类结果提取数据样本,并建立回归模型,最后求解多种偶极子源参数.从而建立起头皮电压和脑电源参数之间的内在联系,为脑电动态分析提出一种实时的研究思路.计算机仿真计算结果证明了此方法的有效性. 相似文献
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目前,自主水下航行器(Autonomous Underwater Vehicle,AUV)研究的重点集中在跟踪定位、精确制导和返坞等领域。机器鱼已成为AUV在智能教育、民用与军事等方面的应用热点。从非线性跟踪分析中发现,区间卡尔曼滤波算法虽然包含了一切可能的滤波结果,但范围比较宽,也比较保守,而且区间数据向量在实现之前是不确定的。文中提出了一种次优区间卡尔曼滤波优化算法。次优区间卡尔曼滤波方案用区间矩阵的逆 代替 其最坏逆,比标准区间卡尔曼滤波更逼近状态方程和测量方程的非线性过程,提高了标称动态系统模型的精确度,改善了跟踪系统的速度与精度。蒙特卡洛仿真实验结果表明,次优区间卡尔曼滤波算法的最优轨迹优于区间卡尔曼滤波方法及标准的卡尔曼滤波方法。 相似文献
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脑电研究领域的两个关键问题是脑电正问题和脑电逆问题,脑电正问题是脑电逆问题的基础.由于复杂、非规则真实头模型中的脑电正问题不存在解析解,因此脑电源分析依赖于正问题数值算法的精度和效率.文章首先详细推导了有限差分算法求解三维各向同性脑电正问题的数学模型,然后在三层同心球模型上通过与解析解比较验证了该算法的精度和效率,最后将该算法应用于真实头模型.仿真结果表明,有限差分法可以有效地处理任意形状几何体的电位场分布问题,是模拟计算真实头模型中脑电正问题的有力工具. 相似文献
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以正向运动学方程为基础,冗余机械臂逆运动学解问题转换为等效最小值问题,提出一种自适应粒子群算法求解该问题。为了保持粒子群的活力,在算法内引入弹射操作。如果粒子满足设定自适应判别函数,粒子将按概率被从当前位置发射到较远区域。为了配合弹射操作,提出一种新的粒子优劣的判断机制,使得粒子可以被弹射飞出可行域。数值实验表明,算法具有较强的全局搜索能力和较快的搜索速度,是求解冗余机械臂逆运动学解的一种有效方法。 相似文献
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天气雷达反射率数据方位分辨率的提高,对中小尺度强对流天气过程的精细探测有重要的意义。以雷达气象积分方程为基础,通过对天气雷达反射率方位数据的过采样,建立雷达测量的低分辨反射率数据与真实气象目标高分辨率数据之间的矩阵方程,提出使用截断奇异值分解算法优化超分辨反演方程逆求解及改善解稳定性。实验结果验证,该方法对反射率数据方位分辨率的提高是行之有效的。 相似文献
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基于集合卡尔曼滤波的反演算法已经成为处理贝叶斯反问题中越来越受欢迎的一类方法.这类方法可以看成是求解反问题的无梯度优化方法.然而这类方法是基于集合卡尔曼滤波算法的,所以它们可能不适用于求解强非高斯性观测模型.为了解决这一问题,在本文中我们提出一种基于仿射映射的变分集合卡尔曼反演算法,即确定一个先验集合到后验集合的仿射映射.数值实验结果表明,在强非高斯性观测模型中,我们提出的反演算法比标准的集合卡尔曼反演方法表现出更好的性能. 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
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. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
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. 相似文献
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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。 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
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. 相似文献
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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. 相似文献
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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 相似文献
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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. 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
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. 相似文献
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《控制理论与应用(英文版)》2014,(3)
正The 34th Chinese Control Conference and SICE Annual Conference 2015(CCCSICE2015)is organized by the Technical Committee on Control Theory(TCCT)of Chinese Association of Automation(CAA)and the Society of Instrument and Control Engineers(SICE)of Japan,and locally organized by Hangzhou Dianzi University(HDU). 相似文献
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该文利用DF与CHI统计量相结合的特征选取方法,针对互联网上对外汉语相关领域的网页进行特征提取,并在此基础上,构建了基于标题与正文相结合的两步式主题相关度判定分类器。基于该分类器做对外汉语相关主题的网页爬取工作,实验表明,效率和召回率比传统分类器都有较大程度的提高,目前该分类器已经用于为大型对外汉语语料库构建提供数据源。 相似文献