Considering the vessel distribution and optic disc (OD) appearance characteristics comprehensively, a novel OD localization method based on 1-D projection is proposed. The horizontal location is determined by vascular...
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ISBN:
(纸本)9781467322164
Considering the vessel distribution and optic disc (OD) appearance characteristics comprehensively, a novel OD localization method based on 1-D projection is proposed. The horizontal location is determined by vascular scatter degree, an evaluation index of vessel distribution. And the vertical location is found by brightness and edge gradient around OD. The proposed method was tested on four publicly-available databases and a self-selection database. The OD was successfully located in 357 images out of 380 images (94%). And the proposed method shows good robustness in both normal and diseased images.
In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extra...
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In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extracted by applying two types of approximation to the time evolution operator, are explicit and implicit scheme in computational electromagnetic simulation, respectively. Since Finite-difference time-domain (FDTD) encounter low accuracy and high dispersion, the more accurate simulation methods can be derived by evaluating the curl operator in the spatial direction with kinds of high order approaches including high order staggered difference, compact finite difference and scaling function approximations. The numerical dispersion of the symplectic and ADI schemes combining with the three high order spatial difference approximations have been analyzed. It has been shown that symplectic scheme combining with compact finite difference and ADI scheme combining with scaling function performance better than other methods. Both schemes can be usefully employed for simulating and solving the large scale electromagnetic problems.
We develop an effective method for improving the segmentation result based on the Multi-Stencils Fast Marching method (MSFM). In MSFM, the gradient information of the image plays a vital role for calculating edges. It...
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Low efficiency of interference calculation has become the bottleneck that restricts further development of the performance of evolutionary algorithm for the polygon layout. To solve the problem, in this paper, we prop...
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This paper has studied spontaneous symmetry breaking (SSB) phenomenon in two types of two-channel asymmetric simple exclusion processes (ASEPs). One common feature of the two systems is that interactions for each spec...
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This paper has studied spontaneous symmetry breaking (SSB) phenomenon in two types of two-channel asymmetric simple exclusion processes (ASEPs). One common feature of the two systems is that interactions for each species of particle happen at only one site, and the system reduces to two independent ASEPs when interaction vanishes. It is shown that with the weakening of interaction, the SSB is suppressed. More interestingly, the SSB disappears before the interaction is eliminated. Our work thus indicates that local interaction has to be strong enough to produce SSB. The mean-field analysis has been carried out, and the results are consistent with the simulation ones.
We present a novel algorithm for point pattern matching by means of spectra of directed graphs. Given a feature point-set, we construct a weighted directed graph and skew-symmetric matrix associated with the graph. By...
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We present a novel algorithm for point pattern matching by means of spectra of directed graphs. Given a feature point-set, we construct a weighted directed graph and skew-symmetric matrix associated with the graph. By using spectral decomposition of the matrix, we give a spectral representation of the feature points with half of the eigenvectors. We theoretically analyze that our method can well deal with the matching problem under affine transformation. The expreiments applied to synthetic data and real-world images show the effectiveness of our method.
In this paper,the fractional variational integrators for fractional variational problems depending on indefinite integrals in terms of Caputo derivative are *** corresponding fractional discrete Euler-Lagrange equatio...
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In this paper,the fractional variational integrators for fractional variational problems depending on indefinite integrals in terms of Caputo derivative are *** corresponding fractional discrete Euler-Lagrange equations are
This paper presents a P-type iterative learning control (ILC) scheme for a class of fractional-order nonlinear time-delay systems with fractional order α (0 ≤ α < 1). By introducing the λ-norm and using a gener...
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This paper presents a P-type iterative learning control (ILC) scheme for a class of fractional-order nonlinear time-delay systems with fractional order α (0 ≤ α < 1). By introducing the λ-norm and using a generalized Gronwall inequality, the *** conditions for the convergence of the control input and the tracking errors for open-loop and closedloop P-type ILC are obtained, respectively. The validity of the methods are *** by a numerical example.
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated d...
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ISBN:
(纸本)9781467317993
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated due to the fact that the left and right circularly polarized waves propagate in the chiral medium with different propagation constants. Numerical results for the normalized near-surface field intensity are given and discussed concisely.
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor tar...
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ISBN:
(纸本)9781467317993
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor targets over a broad frequency band. The FDM, which is based on the equivalent dipole-moment (EDM) method, is employed to reduce impedance matrix storage and accelerate the matrix-vector multiplications in the solutions of the Taylor coefficients. The application of AWE technique enables fast frequency sweep analysis. The numerical results show that this method greatly increased the computational efficiency without losing accuracy conditions compared with the traditional method of moments (MoM) combined with AWE technique.
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