Singular point(SP)extraction is a key component in automatic fingerprint identification system(AFIS).A new method was proposed for fingerprint singular points extraction,based on orientation tensor field and Laurent s...Singular point(SP)extraction is a key component in automatic fingerprint identification system(AFIS).A new method was proposed for fingerprint singular points extraction,based on orientation tensor field and Laurent series.First,fingerprint orientation flow field was obtained,using the gradient of fingerprint image.With these gradients,fingerprint orientation tensor field was calculated.Then,candidate SPs were detected by the cross-correlation energy in multi-scale Gaussian space.The energy was calculated between fingerprint orientation tensor field and Laurent polynomial model.As a global descriptor,the Laurent polynomial coefficients were allowed for rotational invariance.Furthermore,a support vector machine(SVM)classifier was trained to remove spurious SPs,using cross-correlation coefficient as a feature vector.Finally,experiments were performed on Singular Point Detection Competition 2010(SPD2010)database.Compared to the winner algorithm of SPD2010 which has best accuracy of 31.90%,the accuracy of proposed algorithm is 45.34%.The results show that the proposed method outperforms the state-of-the-art detection algorithms by large margin,and the detection is invariant to rotational transformations.展开更多
This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional f...This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2＋1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative（-）, positive（＋） or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive（-,-）, attractive-repulsive（-,＋） or repulsive（＋,＋）, simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.展开更多
This paper is motivated by looking for a loop solution of the Hamiltonian systems such that (0.1) q'(t)+V′(q(t))=0 for t∈ with some T>0 and (0.2) 12|q′(t)| 2+V(q(t))=h ...This paper is motivated by looking for a loop solution of the Hamiltonian systems such that (0.1) q'(t)+V′(q(t))=0 for t∈ with some T>0 and (0.2) 12|q′(t)| 2+V(q(t))=h for t∈ with q(0)=q(T)=x 0 where q∈C 2(, R n 0}), n≥2, x 0∈R n 0} is a fixed point, h∈R is a given number, V∈C 2(R n 0}), R is a potential with a singularity and V′ denotes its gradient. Our main existence results are obtained by a appropriately defined lengthdecreasing (or rather energy decreasing) deformation and a min max procedure which is a combined version of Bahri Rabinowitz and Klingenberg . Our main assumptions are geodesic convex conditions found by the author and the strong force condition of Gordon . As a direct application, for the relativistic gravitational potential V(x)=|x| -1 +|x| -2 or its large scale perturbation, there always exists an almost periodic solution of (0.1)-(0.2) for any h∈R and any x 0∈R n 0} with | x 0 | small enough. This is an interesting phenomenon because we know that there exists no periodic solution of prescribed nonnegative energy for such a Hamiltonian system.展开更多
基金Project(11JJ3080)supported by Natural Science Foundation of Hunan Province,ChinaProject(11CY012)supported by Cultivation in Hunan Colleges and Universities,ChinaProject(ET51007)supported by Youth Talent in Hunan University,China
文摘Singular point(SP)extraction is a key component in automatic fingerprint identification system(AFIS).A new method was proposed for fingerprint singular points extraction,based on orientation tensor field and Laurent series.First,fingerprint orientation flow field was obtained,using the gradient of fingerprint image.With these gradients,fingerprint orientation tensor field was calculated.Then,candidate SPs were detected by the cross-correlation energy in multi-scale Gaussian space.The energy was calculated between fingerprint orientation tensor field and Laurent polynomial model.As a global descriptor,the Laurent polynomial coefficients were allowed for rotational invariance.Furthermore,a support vector machine(SVM)classifier was trained to remove spurious SPs,using cross-correlation coefficient as a feature vector.Finally,experiments were performed on Singular Point Detection Competition 2010(SPD2010)database.Compared to the winner algorithm of SPD2010 which has best accuracy of 31.90%,the accuracy of proposed algorithm is 45.34%.The results show that the proposed method outperforms the state-of-the-art detection algorithms by large margin,and the detection is invariant to rotational transformations.
文摘This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2＋1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative（-）, positive（＋） or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive（-,-）, attractive-repulsive（-,＋） or repulsive（＋,＋）, simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.
文摘This paper is motivated by looking for a loop solution of the Hamiltonian systems such that (0.1) q'(t)+V′(q(t))=0 for t∈ with some T>0 and (0.2) 12|q′(t)| 2+V(q(t))=h for t∈ with q(0)=q(T)=x 0 where q∈C 2(, R n 0}), n≥2, x 0∈R n 0} is a fixed point, h∈R is a given number, V∈C 2(R n 0}), R is a potential with a singularity and V′ denotes its gradient. Our main existence results are obtained by a appropriately defined lengthdecreasing (or rather energy decreasing) deformation and a min max procedure which is a combined version of Bahri Rabinowitz and Klingenberg . Our main assumptions are geodesic convex conditions found by the author and the strong force condition of Gordon . As a direct application, for the relativistic gravitational potential V(x)=|x| -1 +|x| -2 or its large scale perturbation, there always exists an almost periodic solution of (0.1)-(0.2) for any h∈R and any x 0∈R n 0} with | x 0 | small enough. This is an interesting phenomenon because we know that there exists no periodic solution of prescribed nonnegative energy for such a Hamiltonian system.
