Vascular segmentation plays an important role in medical image analysis. A novel technique for the automatic extraction of vascular trees from 2D medical images is presented, which combines Hessian-based multiscale fi...
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Vascular segmentation plays an important role in medical image analysis. A novel technique for the automatic extraction of vascular trees from 2D medical images is presented, which combines Hessian-based multiscale filtering and a modified level set method. In the proposed algorithm, themorphological top-hat transformation is firstly adopted to attenuate background. Then Hessian-based multiscale filtering is used to enhance vascular structures by combining Hessian matrix with Gaussian convolution to tune the filtering response to the specific scales. Because Gaussian convolution tends to blur vessel boundaries, which makes scale selection inaccurate, an improved level set method is finally proposed to extract vascular structures by introducing an external constrained term related to the standard deviation of Gaussian function into the traditional level set. Our approach was tested on synthetic images with vascular-like structures and 2D slices extracted from real 3D abdomen magnetic resonance angiography (MRA) images along the coronal plane. The segmentation rates for synthetic images are above 95%. The results for MRA images demonstrate that the proposed method can extract most of the vascular structures successfully and accurately in visualization. Therefore, the proposed method is effective for the vascular tree extraction in medical images.
In this paper, we investigate multistability of two kinds of recurrent neural networks with time-varying delays and activation functions symmetrical about the origin on the phase plane. One kind of activation function...
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In this paper, we investigate multistability of two kinds of recurrent neural networks with time-varying delays and activation functions symmetrical about the origin on the phase plane. One kind of activation function is with zero slope at the origin on the phase plane, while the other is with nonzero slope at the origin on the phase plane. We derive sufficient conditions under which these two kinds of n-dimensional recurrent neural networks are guaranteed to have (2m + 1)(n) equilibrium points, with (m + 1)(n) of them being locally exponentially stable. These new conditions improve and extend the existing multistability results for recurrent neural networks. Finally, the validity and performance of the theoretical results are demonstrated through two numerical examples.
The globally fixed decay parameter is generally adopted in the traditional nonlocal means method for similarity computation, which has a negative influence on its restoration performance. To address this problem, we p...
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The globally fixed decay parameter is generally adopted in the traditional nonlocal means method for similarity computation, which has a negative influence on its restoration performance. To address this problem, we propose to adaptively tune the decay parameter for each image pixel using the golden section search method based on the pixel-wise minimum mean square error, which can be estimated using the prefiltered result and the estimated noise component. The quantitative and subjective comparisons of restoration performance among the proposed method and several state-of-the-art methods indicate that it can achieve a better performance in noise reduction, artifact avoidance, and detail preservation. (C) 2013 SPIE and IS&T
This paper addresses the stability and stabilization problems for a class of positive linear systems in the presence of saturating *** objective is to give conditions of the stability,and design state feedback control...
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ISBN:
(纸本)9781479900305
This paper addresses the stability and stabilization problems for a class of positive linear systems in the presence of saturating *** objective is to give conditions of the stability,and design state feedback control laws such that the closed-loop systems is asymptotically stable and positive at the origin with a large domain of *** sufficient conditions for stabilization and positivity are derived via the Lyapunov functions method and convex analysis in both the continuous-time and the discrete-time cases,*** state feedback controller design and the estimation of domain of attraction are presented by solving a convex optimization problem with LMIs constraints.A numerical example is given to show the effectiveness of the proposed methods.
Detecting common patterns or motifs in a set of DNA sequences is a major task in computational biology. Recently, this task was formally formulated as a planted (I, d)-motif problem, and several instances of the probl...
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Detecting common patterns or motifs in a set of DNA sequences is a major task in computational biology. Recently, this task was formally formulated as a planted (I, d)-motif problem, and several instances of the problem have been posed as challenges for motif detecting algorithms. In this work, an approach of genetic algorithm using Bayesian inference is proposed to identify (I, d)-motifs, where a modified random projection strategy is applied to generate a good initial population of the genetic algorithm. Based on our method, a program called MRPGA is developed, and experimental results on simulated data show that MRPGA performs better than Random Projection and GARPS in finding weak signal motifs. We test MRPGA on realistic biological data by identifying ERE binding sites of estradiol, CRP in Escherichia coli, as well as transcription factors in E2F family. In real-data applications, MRPGA achieves superior performances comparing with MEME, MDGA, BioProsceptor and BioOptimizor.
Face recognition is one of typical biometric identification method, which has a great prospect in secure authentication system, file management, human-computer interaction and social security. This paper proposes gray...
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ISBN:
(纸本)9781479951529
Face recognition is one of typical biometric identification method, which has a great prospect in secure authentication system, file management, human-computer interaction and social security. This paper proposes gray-scale characteristics and creates facial templates to recognize faces method based on a given number of samples. Firstly, it selects the method of building template according to the number of samples to create the facial template image; then, it will compare the difference of first-order edge entropy between recognition image and the template image and find the best match result; finally, the recognition result is output. Experimental results show that the proposed algorithm has good recognition effect on face recognition under non-constraint conditions.
In this paper, we investigate the consensus problem of a set of discrete-time heterogeneous multi-agent systems with random communication delays represented by a Markov chain, where the multi-agent systems are compose...
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In this paper, we investigate the consensus problem of a set of discrete-time heterogeneous multi-agent systems with random communication delays represented by a Markov chain, where the multi-agent systems are composed of two kinds of agents differed by their dynamics. First, distributed consensus control is designed by employing the event-triggered communication technique, which can lead to a significant reduction of the information communication burden in the multi-agent network. Then, the mean square stability of the closed loop multi-agent systems is analyzed based on the Lyapunov functional method and the Kronecker product technique. Sufficient conditions are obtained to guarantee the consensus in terms of linear matrix inequalities (LMIs). Finally, a simulation example is given to illustrate the effectiveness of the developed theory. (C) 2013 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
In this paper, the problems of exponential stability and L2-gain analysis of event-triggered networked control systems (NCSs) with network-induced delays are studied. We first propose event-triggering conditions in th...
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In this paper, the problems of exponential stability and L2-gain analysis of event-triggered networked control systems (NCSs) with network-induced delays are studied. We first propose event-triggering conditions in the sensor side and controller side, respectively. Because the implementation of our event-triggering scheme only needs periodic supervision of the system state at the constant sampling instants, instead of being monitored continuously, it is expected that the scheme will improve the resource utilization. Taking the network-induced delays into account and using delay system approach, we constructed a unified model of NCSs with hybrid event-triggering schemes. On the basis of this model, sufficient conditions for the exponential stability and L2-gain analysis are developed in the form of LMIs by using a discontinuous Lyapunov-Krasovskii functional approach. Moreover, the corresponding results can be further extended to more general cases, where the system matrices of the considered plant contain parameter uncertainties, represented in either polytopic or norm-bounded frameworks. In addition, as a special case, we also present the exponential stability, L2-gain analysis, and the control feedback gain design of event-triggered NCSs without considering the effects of network-induced delays and event-triggering condition in the controller side. Finally, a simulation example is provided to illustrate the usefulness and effectiveness of the proposed hybrid event-triggering *** (c) 2012 John Wiley & Sons, Ltd.
In this paper, we have integrated the passivity of delayed neural networks with discontinuous activations which are unbounded. Based on differential inclusion theory and nonsmooth analysis, some sufficient conditions ...
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In this paper, we have integrated the passivity of delayed neural networks with discontinuous activations which are unbounded. Based on differential inclusion theory and nonsmooth analysis, some sufficient conditions are presented by means of the generalized Lyapunov method. The results are established in form of linear matrix inequality. In addition, Some numerical examples are proposed to show the effectiveness of the developed results.
This paper proposes a new method for color-texture segmentation based on a splitting framework with graph cut technique. To process the scale difference of quaternion Gabor filter (QGF) features of a color textured im...
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This paper proposes a new method for color-texture segmentation based on a splitting framework with graph cut technique. To process the scale difference of quaternion Gabor filter (QGF) features of a color textured image, a new multiscale QGF (MQGF) is introduced to describe texture attributes of the given image. Then, the segmentation is formulated in terms of energy minimization gradually obtained using binary graph cuts, where color and MQGF features are modeled with a multivariate finite mixture model, and minimum description length (MDL) principle is integrated into this framework as a splitting criterion. In contrast to previous approaches, our method finds an optimal segmentation by balancing energy cost and coding length, and the segmentation result is determined during the splitting process automatically. Experimental results on both synthetic and real natural color textured images demonstrate the good performance of the proposed method. (c) 2013 Elsevier B.V. All rights reserved.
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