共查询到20条相似文献,搜索用时 31 毫秒
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Huang Y Englehart KB Hudgins B Chan AD 《IEEE transactions on bio-medical engineering》2005,52(11):1801-1811
This paper introduces and evaluates the use of Gaussian mixture models (GMMs) for multiple limb motion classification using continuous myoelectric signals. The focus of this work is to optimize the configuration of this classification scheme. To that end, a complete experimental evaluation of this system is conducted on a 12 subject database. The experiments examine the GMMs algorithmic issues including the model order selection and variance limiting, the segmentation of the data, and various feature sets including time-domain features and autoregressive features. The benefits of postprocessing the results using a majority vote rule are demonstrated. The performance of the GMM is compared to three commonly used classifiers: a linear discriminant analysis, a linear perceptron network, and a multilayer perceptron neural network. The GMM-based limb motion classification system demonstrates exceptional classification accuracy and results in a robust method of motion classification with low computational load. 相似文献
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Paulsen KD Meaney PM Moskowitz MJ Sullivan JR 《IEEE transactions on medical imaging》1995,14(3):504-514
The finite element (FE) method has found several applications in emerging imaging modalities, especially microwave imaging which has been shown to be potentially useful in a number of areas including thermal estimation. In monitoring temperature distributions, the biological phenomena of temperature variations of tissue dielectric properties is exploited. By imaging these properties and their changes during such therapies as hyperthermia, temperature distributions can be deduced using difference imaging techniques. The authors focus on a microwave imaging problem where the hybrid element (HE) method is used in conjunction with a dual mesh scheme in an effort to image complex wavenumbers, k(2). The dual mesh scheme is introduced to improve the reconstructed images of tissue properties and is ideally suited for systems using FE methods as their computational base. Since the electric fields typically vary rapidly over a given body when irradiated by high-frequency electromagnetic sources, a dense mesh is needed for these fields to be accurately represented. Conversely, k(2) may be fairly constant over subregions of the body which would allow for a less dense sampling of this parameter in those regions. In the dual mesh system employed, the first mesh, which is uniformly dense, is used for calculating the electric fields over the body whereas the second mesh, which is nonuniform and less dense, is used for representing the k(2) distribution within the region of interest. The authors examine the 2-D TM polarization case for a pair of dielectric distributions on both a large and small problem to demonstrate the flexibility of the dual mesh method along with some of the difficulties associated with larger imaging problems. Results demonstrate the capabilities of the dual mesh concept in comparison to a single mesh approach for a variety of test cases, suggesting that the dual mesh method is critical for FE based image reconstruction where rapidly varying physical quantities are used to recover smoother property profiles, as can occur in microwave imaging of biological bodies. 相似文献
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Unsupervised learning of a finite mixture model based on the Dirichlet distribution and its application 总被引:2,自引:0,他引:2
This paper presents an unsupervised algorithm for learning a finite mixture model from multivariate data. This mixture model is based on the Dirichlet distribution, which offers high flexibility for modeling data. The proposed approach for estimating the parameters of a Dirichlet mixture is based on the maximum likelihood (ML) and Fisher scoring methods. Experimental results are presented for the following applications: estimation of artificial histograms, summarization of image databases for efficient retrieval, and human skin color modeling and its application to skin detection in multimedia databases. 相似文献
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Feng Guang-min Xing-miao 《AEUE-International Journal of Electronics and Communications》2008,62(7):557-564
With a dramatic increase in the number and variety of applications running over the internet, it is very important to be capable of dynamically identifying and classifying flows/traffic according to their network applications. Meanwhile, internet application classification is fundamental to numerous network activities. In this paper, we present a novel methodology for identifying different internet applications. The major contributions are: (1) we propose a Gaussian mixture model (GMM)-based semi-supervised classification system to identify different internet applications; (2) we achieve an optimum configuration for the GMM-based semi-supervised classification system. The effectiveness of these proposed approaches is demonstrated through experimental results. 相似文献
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In the article, an improved variational inference (VI) framework for learning finite Beta-Liouville mixture models (BLM) is proposed for proportional data classification and clustering. Within the VI framework, some non-linear approximation techniques are adopted to obtain the approximated variational object functions. Analytical solutions are obtained for the variational posterior distributions. Compared to the expectation maximization (EM) algorithm which is commonly used for learning mixture models, underfitting and overfitting events can be prevented. Furthermore, parameters and complexity of the mixture model (model order) can be estimated simultaneously. Experiment shows that both synthetic and real-world data sets are to demonstrate the feasibility and advantages of the proposed method. 相似文献
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Selleri S. Bolli P. Pelosi G. 《Electromagnetic Compatibility, IEEE Transactions on》2004,46(2):309-311
Zones with nonlinear behavior on an object cause intermodulated components in the scattered electromagnetic field. This problem is relevant both for satellite communications and for radio-astronomical applications. Recently, a heuristic model for the passive intermodulation analysis has been derived in a time domain physical optics framework. The heuristic approach proposed requires the determination of few coefficients. Here, a genetic algorithm is introduced for the computation of the optimum values for these coefficients. 相似文献
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Sungwook Kim 《Wireless Networks》2014,20(5):889-898
Nowadays, Multi-hop Relaying Network (MRN) has gained wide acceptance as a next step towards future radio networks. MRN can extend the service area as well as improve the performance of wireless networks. To exploit the multi-hop relaying operation, an important issue is how to properly control wireless bandwidth. In this paper, a new bandwidth management scheme is proposed for MRNs. By integrating the random arrival rule and Nash bargaining model, the proposed scheme adaptively controls the wireless bandwidth to maximize network efficiency. In our scheme, trust value and bargaining powers are decided according to the Bayesian inference and real-time negotiation process, respectively. This approach can make the network system be close to the optimized network performance. To prove the effectiveness of the proposed scheme, a simulation has carried out. The results demonstrate the effectiveness of the proposed scheme in comparison with other existing schemes. 相似文献
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This paper presents genetic algorithms for solving various reliability design problems, which include series systems, series–parallel systems and complex (bridge) systems. The objective is to maximize the system reliability, while maintaining feasibility with respect to three nonlinear constraints, namely, cost and weight constraints, and constraints on the products of volume and weight. In this paper, mixed-integer reliability problems are studied. Numerical examples show that genetic algorithms perform well for all the reliability problems considered in this paper. In particular, as reported, some solutions obtained by genetic algorithms are better than previously best-known solutions. 相似文献
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对遗传算法求解TSP问题进行了完整的描述。介绍几种交叉算子和变异算子,并对其作了比较。提出对算法的交叉概率、变异概率进行自适应调整以维护群体多样性,防止算法过早收敛。 相似文献
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The authors present a new algorithm for identifying the distribution of different material types in volumetric datasets such as those produced with magnetic resonance imaging (MRI) or computed tomography (CT). Because the authors allow for mixtures of materials and treat voxels as regions, their technique reduces errors that other classification techniques can create along boundaries between materials and is particularly useful for creating accurate geometric models and renderings from volume data. It also has the potential to make volume measurements more accurately and classifies noisy, low-resolution data well. There are two unusual aspects to the authors' approach. First, they assume that, due to partial-volume effects, or blurring, voxels can contain more than one material, e.g., both muscle and fat; the authors compute the relative proportion of each material in the voxels. Second, they incorporate information from neighboring voxels into the classification process by reconstructing a continuous function, ρ(x), from the samples and then looking at the distribution of values that ρ(x) takes on within the region of a voxel. This distribution of values is represented by a histogram taken over the region of the voxel; the mixture of materials that those values measure is identified within the voxel using a probabilistic Bayesian approach that matches the histogram by finding the mixture of materials within each voxel most likely to have created the histogram. The size of regions that the authors classify is chosen to match the sparing of the samples because the spacing is intrinsically related to the minimum feature size that the reconstructed continuous function can represent 相似文献
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针对高斯混合模型在阴影不显著情况下,容易把随光线突变而变化的背景像素点当作前景目标从而造成目标误检的缺点,提出了一种基于改进的高斯混合模型的红外人体目标检测方法。该方法引入边缘检测信息增强红外人体目标检测效果。首先,该算法利用Canny边缘检测来提取人体目标的边缘信息。然后,以此对每个像素建立高斯混合模型来完成人体目标的检测。实验结果表明,该方法能够有效消除光照突变所产生的阴影影响,提高了检测的准确性。 相似文献
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Genetic algorithms in engineering electromagnetics 总被引:10,自引:0,他引:10
This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for the potential user. Extensive use is made of sidebars and graphical presentation to facilitate understanding. The tutorial is followed by a discussion of several electromagnetic applications in which the GA has proven useful. The applications discussed include the design of lightweight, broadband microwave absorbers, the reduction of array sidelobes in thinned arrays, the design of shaped-beam antenna arrays, the extraction of natural resonance modes of radar targets from backscattered response data, and the design of broadband patch antennas. Genetic-algorithm optimization is shown to be suitable for optimizing a broad class of problems of interest to the electromagnetic community. A comprehensive list of key references, organized by application category, is also provided 相似文献
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火灾作为对社会和环境危害最大的灾难,一直是人们重点防范的对象.但目前现有的火灾预警系统都存在误报率过高的问题.因此,文中提出了一种基于火焰闪烁动力学的火焰检测框架.在该框架中,火焰颜色分布模型采用高斯混合模型.此外,采用概率显著性分析方法和一维小波变换提取运动显著性和滤波后的时间序列作为特征,描述火焰的动态特性和闪烁特... 相似文献
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Hyperspectral imaging (HSI) is the emerging method that combines traditional imaging and spectroscopy to provide the image with both the spatial and spectral information of the object present in the image. The major challenges of the existing techniques for HSI classification are the high dimensionality of data and its complexity in classification. This paper devises a new technique to classify the HSI named Spatial–Spectral Schroedinger Eigen Maps based Multi-scale adaptive sparse representation (S2SEMASR). In this, two different phases are employed for the accurate classification of the HSI, namely, Schroedinger Eigen maps (SE) based spatial–spectral feature extraction and multi-scale adaptive sparse classification for the feature extracted image. SE makes use of spatial–spectral cluster potentials which allows the extraction of features that best describes the characteristics of different classes of HSI. The multiscale adaptive sparse representation (MASR) applied over the SE features provides the sparse coefficients that includes distinct scale level sparsity with same class level sparsity. With the obtained coefficients, the class label of each pixel is determined. The proposed HSI classifier well utilizes the spectral and spatial characteristics to exploit the within-class variability and thus reduces the misclassification of similar test pixels Experimental results demonstrated that the proposed S2SEMASR approach outperforms the traditional results both qualitatively and quantitatively with an overall accuracy of 98.3%. 相似文献