An adaptive soft sensor modeling method based on weighted supervised latent factor analysis is proposed. In conventional moving window based adaptive soft sensor, predictive model is constructed only with the latest p...
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It is important to accurately fit the unknown probability density functions of background or object. To solve this problem, the Burr distribution is introduced. Three-parameter Burr distribution can cover a wide range...
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ISBN:
(纸本)9780819493132
It is important to accurately fit the unknown probability density functions of background or object. To solve this problem, the Burr distribution is introduced. Three-parameter Burr distribution can cover a wide range of distribution. The expectation maximization algorithm is used to deal with the estimation difficulty in the Burr distribution model. The expectation maximization algorithm starts from a set of selected appropriate parameters' initial values, and then iterates the expectation-step and maximization-step until convergence to produce result parameters. The experiment results show that the Burr distribution could depicts quite successfully the probability density function of a significant class of image, and comparatively the method has low computing complexity.
Distribution system state estimation (DSSE) is an essential tool in active distribution grids in order to enhance the awareness of the power system operators regarding the state of the distribution system. One of the ...
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ISBN:
(纸本)9781479976959
Distribution system state estimation (DSSE) is an essential tool in active distribution grids in order to enhance the awareness of the power system operators regarding the state of the distribution system. One of the peculiarities of the DSSE is the lack of adequate real-time measurements. Thus, in this paper a three-phase DSSE algorithm enhanced with an advanced approach for modeling pseudomeasurements is proposed. The major innovation of the proposed methodology is the development of a DSSE algorithm based on limited real-time measurements. The proposed DSSE algorithm takes into account the unbalanced nature of the distribution systems and the presence of virtual measurements. The pseudomeasurements are obtained from historical data, through a Gaussian Mixture Model (GMM) methodology, improved by the Calinski & Harabasz (CH) criterion and the expectationmaximization (EM) algorithm. The performance of the proposed methodology is illustrated on the IEEE 13 node test feeder and compared with the case where the pseudomeasurements are modeled through a normal distribution.
Incremental expectationmaximization (EM) algorithms were introduced to design EM for the large scale learning framework by avoiding the full data set to be processed at each iteration. Nevertheless, these algorithms ...
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ISBN:
(纸本)9781728157672
Incremental expectationmaximization (EM) algorithms were introduced to design EM for the large scale learning framework by avoiding the full data set to be processed at each iteration. Nevertheless, these algorithms all assume that the conditional expectations of the sufficient statistics are explicit. In this paper, we propose a novel algorithm named Perturbed Prox-Preconditioned SPIDER (3P-SPIDER), which builds on the Stochastic Path Integral Differential EstimatoR EM (SPIDER-EM) algorithm. The 3P-SPIDER algorithm addresses many intractabilities of the E-step of EM;it also deals with non-smooth regularization and convex constraint set. Numerical experiments show that 3P-SPIDER outperforms other incremental EM methods and discuss the role of some design parameters.
Graphical models have been extensively used in, and provided novel insights across, a wide variety of research areas. Most current graph estimation methods assume a sparse structure. However, a sparse-only assumption ...
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ISBN:
(纸本)9798350373981;9798350373974
Graphical models have been extensively used in, and provided novel insights across, a wide variety of research areas. Most current graph estimation methods assume a sparse structure. However, a sparse-only assumption is limiting and unrealistic in practice, hence sparse and low-rank forms have been suggested. In this work, we propose a new estimation method called sparse low-rank inverse covariance estimation (SLICE), which is a direct approach to jointly estimate the sparse and latent components of a Gaussian graphical model. SLICE utilizes a simple regularization term to ensure accurate estimates that are congruent with the covariance matrix. We derive an efficient and generalizable pseudo expectationmaximization (EM) algorithm to solve for this estimator. Simulation and neuroimaging studies demonstrate the improvement of our SLICE approach over current state-of-the-art methods.
Case-based reasoning is a problem-solving technique commonly seen in artificial intelligence. A successful CBR system highly depends on how to design an effective case retrieval mechanism. The K-nearest neighbor (KNN)...
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ISBN:
(纸本)9780769536538
Case-based reasoning is a problem-solving technique commonly seen in artificial intelligence. A successful CBR system highly depends on how to design an effective case retrieval mechanism. The K-nearest neighbor (KNN) search method which selects the K most similar prior cases for a new case has been extensively used in the case retrieval phase of CBR. Although KNN can be simply implemented, the choice of the K value is quite subjective and wit] influence the performance of a CBR system. To eliminate the disadvantage, this research proposes a significant nearest neighbor (SNN) search method. In SNN, the probability density function of the dissimilarity distribution is estimated by the expectation maximization algorithm. Accordingly, the case selection can be conducted by determining whether the dissimilarity between a prior case and the new case is significant low based on the estimated dissimilarity distribution. The SNN search avoids human involvement in deciding the number of retrieved prior cases and makes the retrieval result objective and meaningful in statistics. The performance of the proposed SNN search method is demonstrated through a set of experiments.
Graph Neural Networks (GNNs) are crucial for machine learning applications with graph-structured data, but their success depends on sufficient labeled data. We present a novel active learning (AL) method for GNNs, ext...
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ISBN:
(纸本)9781713899921
Graph Neural Networks (GNNs) are crucial for machine learning applications with graph-structured data, but their success depends on sufficient labeled data. We present a novel active learning (AL) method for GNNs, extending the Expected Model Change maximization (EMCM) principle to improve prediction performance on unlabeled data. By presenting a Bayesian interpretation for the node embeddings generated by GNNs under the semi-supervised setting, we efficiently compute the closed-form EMCM acquisition function as the selection criterion for AL without re-training. Our method establishes a direct connection with expected prediction error minimization, offering theoretical guarantees for AL performance. Experiments demonstrate our method's effectiveness compared to existing approaches, in terms of both accuracy and efficiency.
The problem of image formation for X-ray transmission tomography is formulated as a statistical inverse problem. The maximum likelihood estimate of the attenuation function is sought. Using convex optimization methods...
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ISBN:
(纸本)0819452025
The problem of image formation for X-ray transmission tomography is formulated as a statistical inverse problem. The maximum likelihood estimate of the attenuation function is sought. Using convex optimization methods, maximizing the log-likelihood functional is equivalent to a double minimization of I-divergence, one of the minimizations being over the attenuation function. Restricting the minimization over the attenuation function to a coarse grid component forms the basis for a multigrid algorithm that is guaranteed to monotonically decrease the I-divergence at every iteration on every scale.
Lung disease is often performed as nodules. Pulmonary nodule is one of important symbols of lung disease. Characteristics of pulmonary nodules always indicate the nature of lung disease. Detection of pulmonary nodules...
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ISBN:
(纸本)9781479949557
Lung disease is often performed as nodules. Pulmonary nodule is one of important symbols of lung disease. Characteristics of pulmonary nodules always indicate the nature of lung disease. Detection of pulmonary nodules has great significance in diagnosing lung cancer. Study of pulmonary nodules is now a hot research. CT is a new type of medical imaging equipment with a high density resolution and adequate image information. But to detect small pulmonary nodes, radiologists need to read a lot of images. It could easily lead to misdiagnosis and miss-diagnosis. This paper uses EM algorithm in CT images for the lung nodule detection and segmentation. The application shows that the method of this paper is to improve the early detection rate of lung cancer nodules and one of the effective methods using computer-aided analysis of lung nodules. The algorithm used is simple, effective and practical.
We propose a method to classify human trajectories, modeled by a set of motion vector fields, each tailored to describe a specific motion regime. Trajectories are modeled as being composed of segments corresponding to...
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ISBN:
(纸本)9781424479948
We propose a method to classify human trajectories, modeled by a set of motion vector fields, each tailored to describe a specific motion regime. Trajectories are modeled as being composed of segments corresponding to different motion regimes, each generated by one of the underlying motion fields. Switching among the motion fields follows a probabilistic mechanism, described by a field of stochastic matrices. This yields a space-dependent motion model which can be estimated using an expectation-maximization (EM) algorithm. To address the model selection question (how many fields to use?), we adopt a discriminative criterion based on classification accuracy on a held out set. Experiments with real data (human trajectories in a shopping mall) illustrate the ability of the proposed approach to classify complex trajectories into high level classes (client versus non-client).
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