Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
Articles 1 - 8 of 8
Full-Text Articles in Mathematics
Deformable Image Registration With Inclusion Of Auto-Detected Homologous Tissue Features, Y. Xie, Lei Xing, Dana C. Paquin, Doron Levy, T. Yang
Deformable Image Registration With Inclusion Of Auto-Detected Homologous Tissue Features, Y. Xie, Lei Xing, Dana C. Paquin, Doron Levy, T. Yang
Mathematics
No abstract provided.
Hybrid Multiscale Landmark And Deformable Image Registration, Dana C. Paquin, Doron Levy, Lei Xing
Hybrid Multiscale Landmark And Deformable Image Registration, Dana C. Paquin, Doron Levy, Lei Xing
Mathematics
An image registration technique is presented for the registration of medical images using a hybrid combination of coarse-scale landmark and B-splines deformable registration techniques. The technique is particularly effective for registration problems in which the images to be registered contain large localized deformations. A brief overview of landmark and deformable registration techniques is presented. The hierarchical multiscale image decomposition of E. Tadmor, S. Nezzar, and L. Vese, A multiscale image representation using hierarchical (BV,L2) decompositions, Multiscale Modeling and Simulations, vol. 2, no. 4, pp. 554-579, 2004, is reviewed, and an image registration algorithm is developed based on …
The Q-Exponential Generating Function For Permutations By Consecutive Patterns And Inversions, Don Rawlings
The Q-Exponential Generating Function For Permutations By Consecutive Patterns And Inversions, Don Rawlings
Mathematics
The inverse of Fedou's insertion-shift bijection is used to deduce a general form for the q-exponential generating function for permutations by consecutive patterns (overlaps allowed) and inversion number from a result due to Jackson and Goulden for enumerating words by distinguished factors. Explicit q-exponential generating functions are then derived for permutations by the consecutive patterns 12…m, 12…(m−2)m(m−1), 1m(m−1)…2, and by the pair of consecutive patterns (123,132).
Closed Geodesics On Orbifolds Of Revolution, Joseph E. Borzellino, Christopher R. Jordan-Squire, Gregory C. Petrics, D. Mark Sullivan
Closed Geodesics On Orbifolds Of Revolution, Joseph E. Borzellino, Christopher R. Jordan-Squire, Gregory C. Petrics, D. Mark Sullivan
Mathematics
Using the theory of geodesics on surfaces of revolution, we show that any two-dimensional orbifold of revolution homeomorphic to S2 must contain an infinite number of geometrically distinct closed geodesics. Since any such orbifold of revolution can be regarded as a topological two-sphere with metric singularities, we will have extended Bangert's theorem on the existence of infinitely many closed geodesics on any smooth Riemannian two-sphere. In addition, we give an example of a two-sphere cone-manifold of revolution which possesses a single closed geodesic, thus showing that Bangert's result does not hold in the wider class of closed surfaces with …
Vorticity Dynamics And Sound Generation In Two-Dimensional Fluid Flow, Raymond J. Nagem, Guido Sandri, David Uminsky
Vorticity Dynamics And Sound Generation In Two-Dimensional Fluid Flow, Raymond J. Nagem, Guido Sandri, David Uminsky
Mathematics
An approximate solution to the two-dimensional incompressible fluid equations is constructed by expanding the vorticity field in a series of derivatives of a Gaussian vortex. The expansion is used to analyze the motion of a corotating Gaussian vortex pair, and the spatial rotation frequency of the vortex pair is derived directly from the fluid vorticity equation. The resulting rotation frequency includes the effects of finite vortex core size and viscosity and reduces, in the appropriate limit, to the rotation frequency of the Kirchhoff point vortex theory. The expansion is then used in the low Mach number Lighthill equation to derive …
Relationships Between Braid Length And The Number Of Braid Strands, Cornelia A. Van Cott
Relationships Between Braid Length And The Number Of Braid Strands, Cornelia A. Van Cott
Mathematics
For a knot K, let ℓ(K,n) be the minimum length of an n–stranded braid representative of K. Fixing a knot K, ℓ(K,n) can be viewed as a function of n, which we denote by ℓK(n). Examples of knots exist for which ℓK(n) is a nonincreasing function. We investigate the behavior of ℓK(n), developing bounds on the function in terms of the genus of K. The bounds lead to the conclusion that for any knot K the function ℓK(n) is eventually stable. We study the stable behavior of ℓK(n), with stronger results for homogeneous knots. For knots of nine or fewer …
Π01 Classes And Strong Degree Spectra Of Relations, John Chisholm, Jennifer Chubb, Valentina S. Harizanov, Denise R. Hirschfeldt, Carl G. Jockusch, Timothy H. Mcnicholl, Sarah Pingrey
Π01 Classes And Strong Degree Spectra Of Relations, John Chisholm, Jennifer Chubb, Valentina S. Harizanov, Denise R. Hirschfeldt, Carl G. Jockusch, Timothy H. Mcnicholl, Sarah Pingrey
Mathematics
We study the weak truth-table and truth-table degrees of the images of subsets of computable structures under isomorphisms between computable structures. In particular, we show that there is a low c.e. set that is not weak truth-table reducible to any initial segment of any scattered computable linear order. Countable Π01 subsets of 2w and Kolmogorov complexity play a major role in the proof.
Unbounded Regions Of Infinitely Logconcave Sequences, David Uminsky, Karen Yeats
Unbounded Regions Of Infinitely Logconcave Sequences, David Uminsky, Karen Yeats
Mathematics
We study the properties of a logconcavity operator on a symmetric, unimodal subset of finite sequences. In doing so we are able to prove that there is a large unbounded region in this subset that is ∞-logconcave. This problem was motivated by the conjecture of Boros and Moll in [1] that the binomial coefficients are ∞-logconcave.