다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Clustering algorithms are attractive for the task of class identification in spatial databases. However, the application to large spatial databases rises the following requirements for clustering algorithms: minimal requirements of domain knowledge to determine the input parameters, discovery of clusters with arbitrary shape and good efficiency on large databases. The well-known clustering algorithms offer no solution to the combination of these requirements. In this paper, we present the new clustering algorithm DBSCAN relying on a density-based notion of clusters which is designed to discover clusters of arbitrary shape. DBSCAN requires only one input parameter and supports the user in determining an appropriate value for it. We performed an experimental evaluation of the effectiveness and efficiency of DBSCAN using synthetic data and real data of the SEQUOIA 2000 benchmark. The results of our experiments demonstrate that (1) DBSCAN is significantly more effective in discovering clusters of arbitrary shape than the well-known algorithm CLAR-ANS, and that (2) DBSCAN outperforms CLARANS by a factor of more than 100 in terms of efficiency.

A density-based algorithm for discovering clusters a density-based algorithm for discovering clusters in large spatial databases with noise

Clustering algorithms are attractive for the task of class identification in spatial databases. However, the application to large spatial databases rises the following requirements for clustering algorithms: minimal requirements of domain knowledge to determine the input parameters, discovery of clusters with arbitrary shape and good efficiency on large databases. The well-known clustering algorithms offer no solution to the combination of these requirements. In this paper, we present the new clustering algorithm DBSCAN relying on a density-based notion of clusters which is designed to discover clusters of arbitrary shape. DBSCAN requires only one input parameter and supports the user in determining an appropriate value for it. We performed an experimental evaluation of the effectiveness and efficiency of DBSCAN using synthetic data and real data of the SEQUOIA 2000 benchmark. The results of our experiments demonstrate that (1) DBSCAN is significantly more effective in discovering clusters of arbitrary shape than the well-known algorithm CLARANS, and that (2) DBSCAN outperforms CLARANS by a factor of more than 100 in terms of efficiency.

/pdf/a-density-based-algorithm-for-discovering-clusters-in-large-1o5u8sf38m.pdf

A density-based algorithm for discovering clusters in large spatial Databases with Noise

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

In this paper we propose a novel Bayesian algorithm for image restoration and parameter estimation. We utilize an image prior where Gaussian distributions are placed per pixel in the high-pass filter outputs of the image. By following the hierarchical Bayesian framework, we simultaneously estimate the unknown image and hyperparameters for both the image prior and the image degradation noise. We show that the proposed formulation is a special case of the popular l p -norm based formulations with p = 0, and therefore enforces sparsity to an high extent in the filtered image coefficients. Moreover, the proposed formulation results in a convex optimization problem, and therefore does not suffer from the robustness issues common with non-convex image priors. Experimental results demonstrate that the proposed algorithm provides superior performance compared to state-of-the-art restoration algorithms although no user-supervision is required.

/pdf/sparse-bayesian-image-restoration-2mtncyzo0f.pdf

Sparse Bayesian image restoration

A Bayesian method to deconvolve images when the location of the objects in the image is known in advance is presented. This knowledge of location is incorporated into the prior model via a labeling process. An iterative method is proposed to find the maximum a posteriori estimator of the image. The method was tested on both synthetic images and ground-based CCD images of Saturn with very encouraging results

Bayesian deconvolution with prior knowledge of object location : applications to ground-based planetary images

In this paper we propose novel algorithms for image restoration and parameter estimation with a generalized Gaussian Markov random field (GGMRF) prior utilizing variational distribution approximation. The restored image and the unknown hyperparameters for both the image prior and the image degradation noise are simultaneously estimated within a hierarchical Bayesian framework. We develop two algorithms resulting from this formulation which provide approximations to the posterior distributions of the latent variables. Experimental results are provided to demonstrate the performance of the algorithms.

/pdf/generalized-gaussian-markov-random-field-image-restoration-1prdzbd96m.pdf

Generalized Gaussian Markov random field image restoration using variational distribution approximation

In this paper we propose a novel algorithm for the pansharpening of multispectral images based on the use of a Total Variation (TV) image prior. Within the Bayesian formulation, the proposed methodology incorporates prior knowledge on the expected characteristics of multispectral images, and uses the sensor characteristics to model the observation process of both panchromatic and multispectral images. Using real and synthetic data, the pansharpened multispectral images are compared with the images obtained by other pansharpening methods and their quality is assessed both qualitatively and quantitatively.

/pdf/super-resolution-of-multispectral-images-using-tv-image-1hm757nt3g.pdf

Super Resolution of Multispectral Images Using TV Image Models

We propose a new image and blur prior model, based on non-stationary autoregressive (AR) models, and use these to blindly deconvolve blurred photographic images, using the Gibbs sampler. As far as we are aware, this is the first attempt to tackle a real-world blind image deconvolution (BID) problem using Markov chain Monte Carlo (MCMC) methods. We give examples with simulated and real out-of-focus images, which show the state-of-the-art results that the proposed approach provides.

/pdf/blind-restoration-of-blurred-photographs-via-ar-modelling-23spvi6ohu.pdf

Rafael Molina

Papers

Sparse Bayesian image restoration

Bayesian deconvolution with prior knowledge of object location : applications to ground-based planetary images

Generalized Gaussian Markov random field image restoration using variational distribution approximation

Super Resolution of Multispectral Images Using TV Image Models

Blind restoration of blurred photographs via AR modelling and MCMC