共查询到20条相似文献，搜索用时 31 毫秒
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为准确检测和分离电力系统中日益严重的谐波污染,提出基于稀疏盲分离的谐波分析方法。首先利用延迟采样构建两路观测信号,建立电能质量谐波盲源分离的数学模型。然后对两路观测信号进行短时傅里叶变换,采用基于点密度的弧灭圆聚类方法,对频域散点图上样本点进行聚类以估计混合矩阵。最后通过求解最小L1范数方法分离各次谐波分量。对仿真信号和实际地铁电力信号的测试结果表明,所提方法能准确分离各次谐波的同时,在计算效率和分离含有量低的高次谐波方面优势明显。 相似文献
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在测控、导航、雷达等领域,为了保证时间和频率的统一,需要对时统的铷钟及高稳晶振等设备进行高精度频率测量.根据频差倍增法测试原理,以铯原子频率标准FTS4040A为核心,设计开发了一套多通道的铯原子频标自动检定系统.首先介绍了系统软、硬件的设计情况,分析了频率测量系统常用的频差倍增技术,然后对基于频差倍增法的测试原理以及系统的关键技术进行了较为详细的阐述.结果表明,系统实现了同时检定14台被检设备各项指标的能力,并提高了测量精度. 相似文献
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建立了一种双模型电阻抗成像系统,旨在解决一元模型电阻抗成像系统中耗时较多的问题。基于精细化三维圆柱体模型进行电阻抗正问题分析,采用粗梳三维圆柱体模型进行逆问题求解。在双模型成像系统中,基于稀疏矩阵建立映射公式实现粗疏有限元单元和精细有限元单元的匹配和转换。通过计算机仿真,在该系统中运用基于修正的Laplace Guass‐New ton重建算法可以得到相应的阻抗重建图像,实验结果验证了双模型系统的正确性和可行性。 相似文献
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电阻抗成像(electrical impedance tomography,EIT)作为一种非侵入式的医学成像技术,其重建过程是一个难以计算的病态逆问题.为了保证EIT成像精度并提高运算速度,设计了基于多层神经网络(multilayer artificial neural network,MANN)的电阻抗成像逆问题求... 相似文献
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针对现有方法受背景谐波随机波动影响而导致系统谐波阻抗估计误差大的问题,提出一种基于概率统计的系统谐波阻抗估计方法。采用3阶加权高斯混合分布函数建立系统谐波电压概率模型,以反映背景谐波的随机波动性。构建系统谐波阻抗的对数似然方程,采用确定性退火算法对期望最大化方法进行改进,提高了隐变量的估计精度和迭代速度,实现对背景谐波随机性波动下系统谐波阻抗估计。采用KL散度和误差对该方法背景谐波概率模型的准确性和系统谐波阻抗的估计精度进行评价,并采用仿真实验分析和实测数据实验对该方法的估计效果进行分析,实验分析表明,该方法对系统谐波阻抗估计具有较强的稳健性和较高的准确性。 相似文献
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V. R. Kumar N. Mani 《International Journal of Adaptive Control and Signal Processing》1994,8(4):379-392
There is an increasing concern among the scientific community and industrialists over the safe and reliable operation of control systems in industries. Although several adaptive control techniques have been introduced, they are not robust enough for many real-world problem domains where the degree of uncertainty is high and therefore classical methods of mathematical modelling and control fail. Computer technology has reached a point where machine intelligence can be incorporated in many of the systems that we use daily. Changes in environments, unmeasurable disturbances, changing reference models and performance criteria and component failures are some of the characteristics which necessitate intelligent control. the developments in the field of artificial intelligence have reached a stage which will help to reduce these control complexities by incorporating intelligence into the control systems. In this paper we explain various artificial intelligence techniques that can be used to control dynamical physical systems. 相似文献
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称重传感器神经网络补偿器设计 总被引：6，自引：0，他引：6
吴忠强 《电子测量与仪器学报》2004,18(1):42-46
为满足快速称重的要求,设计出一种新型的称重传感器神经网络补偿器.仿真表明有效的提高了称重传感器的动态响应性能,有推广应用价值. 相似文献
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This paper proposes a novel grading method of apples, in an automated grading device that uses convolutional neural networks to extract the size, color, texture, and roundness of an apple. The developed machine learning method uses the ability of learning representative features by means of a convolutional neural network (CNN), to determine suitable features of apples for the grading process. This information is fed into a one-to-one classifier that uses a support vector machine (SVM), instead of the softmax output layer of the CNN. In this manner, Yantai apples with similar shapes and low discrimination are graded using four different approaches. The fusion model using both CNN and SVM classifiers is much more accurate than the simple k-nearest neighbor (KNN), SVM, and CNN model when used separately for grading, and the learning ability and the generalization ability of the model is correspondingly increased by the combined method. Grading tests are carried out using the automated grading device that is developed in the present work. It is verified that the actual effect of apple grading using the combined CNN-SVM model is fast and accurate, which greatly reduces the manpower and labor costs of manual grading, and has important commercial prospects. 相似文献
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In this paper, an automated system and methodology for nondestructive sorting of apples are presented. Different from the traditional manual grading method, the automated, nondestructive sorting equipment can improve the production efficiency and the grading speed and accuracy. Most popular apple quality detection and grading methods use two-dimensional (2D) machine vision detection based on a single charge-coupled device (CCD) camera detect the external quality. Our system integrates a 3D structured laser into an existing 2D sorting system, which provides the addition third dimension to detect the defects in apples by using the curvature of the structured light strips that are acquired from the optical system of the machine. The curvature of the structured light strip will show the defects in the apple surface. Other features such as color, texture, shape, size and 3D information all play key roles in determining the grade of an apple, which can be determined using a series of feature extraction methods. After feature extraction, a method based on principal component analysis (PCA) for data dimensionality reduction is applied to the system. Furthermore, a comprehensive classification method based on fuzzy neural network (FNN), which is a combination of knowledge-based and model-based method, is used in this paper as the classifier. Preliminary experiments are conducted to verity the feasibility and accuracy of the proposed sorting system. 相似文献
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Of the many kinds of renewable energy, wind power is low in cost and non-polluting, so it is especially well-suited to Taiwan. The Mai Liao Wind Farm is the most important wind farm in Taiwan, and forecasting the wind power output for national sustainable development continues to be a challenging research feature. In this study, we attempt to forecast the wind power data collected from the Mai Liao Wind Farm. Our forecast model is based on a Multi-Layer Perceptron Artificial Neural Network (MLP) model using the data collected at the Mai Liao Wind Farm over a period of five years from September 2002 to August 2007. We proposed a new algorithm, namely improved Simplified Swarm Optimization (iSSO), which improves Simplified Swarm Optimization (SSO) by justifying the weights and bias in training the MLP. The proposed iSSO combines Principal Component Analysis (PCA), Autocorrelation Function (AF) and Partial Autocorrelation Function (PAF) for the selection of features which increases the efficiency of the proposed model. The experimental results demonstrate that the performance of iSSO outperforms the other six most popular algorithms. 相似文献
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基于连续映射分析，本文提出了一种应用单隐层前馈神经网络决定多机系统中两电站间暂态稳定协调控制规律的方法，包括两电站间协调切机和一电站切机与另一电站快速汽门控制间协调两方式，新英格兰１０机试例系统中两电站协调切机控制的领导 具结果也表明了本文方法的有效性。 相似文献
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提出一种智能洗胃的设计方案。利用微处理器采集和计算模拟洗胃试验中的洗胃压力、压力变化率、液位、液位变化率、浑浊度和PH值等信号,通过神经网络算法对信号进行处理,判断洗胃工况。采用神经网络算法能区分管路堵塞、不完全堵塞、故障、洗胃正常和清洁等运行状态。神经网络算法可用于柔性密闭容器的清洗工作。 相似文献
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Up to 7 days ahead electrical peak load forecasting has been done using feed forward neural network based on Steepest descent, Bayesian regularization, Resilient and adaptive backpropagation learning methods, by incorporating the effect of eleven weather parameters and past peak load information. To avoid trapping of network into a state of local minima, the optimization of user-defined parameters viz., learning rate and error goal has been performed. The sliding window concept has been incorporated for selection of training data set. It was then reduced as per relevant selection according to the day type and season for which the forecast is made. To reduce the dimensionality of input matrix, the Principal Component Analysis method of factor extraction or correlation analysis technique has been used and their performance has been compared. The resultant data set was used for training of three-layered neural network. In order to increase the learning speed, the weights and biases were initialized according to Nguyen and Widrow method. To avoid over fitting, early stopping of training was done at the minimum validation error. 相似文献
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信息融合技术在传感器网络中的应用研究 总被引：4，自引：1，他引：4
综合了传感器技术、嵌入式技术和无线通讯技术的传感器网络是一种全新的信息获取与处理手段。通过分析其面临的问题,提出用多传感器信息融合技术处理网络节点感知数据。通过传感器分类研究、时空对准研究、信息预处理研究、分布式检测与估计研究和多传感器协调管理研究,旨在提高网络节点感知效能,延长网络生命周期,减少时间延迟。 相似文献