4,437 research outputs found
General Volume-Preserving Mechanical Systems
In this letter, we present the general form of equations that generate a
volume-preserving flow on a symplectic manifold (M, \omega). It is shown that
every volume-preserving flow has some 2-forms acting the role of the
Hamiltonian functions in the Hamiltonian mechanics and the ordinary Hamilton
equations are included as a special case with a 2-form \frac{1}{n-1} H \omega
where H is the corresponding Hamiltonian.Comment: Plain LaTeX, 13 pages, no figure
On Torsion and Nieh-Yan Form
Using the well-known Chern-Weil formula and its generalization, we
systematically construct the Chern-Simons forms and their generalization
induced by torsion as well as the Nieh-Yan (N-Y) forms. We also give an
argument on the vanishing of integration of N-Y form on any compact manifold
without boundary. A systematic construction of N-Y forms in D=4n dimension is
also given.Comment: 7 pages, latex, no figure
Dublin City University at CLEF 2007: Cross-Language Speech Retrieval Experiments
The Dublin City University participation in the CLEF 2007 CL-SR English task concentrated primarily on issues of topic translation. Our retrieval system used the BM25F model and pseudo relevance feedback. Topics were translated into English using the Yahoo! BabelFish free online service combined with domain-specific translation lexicons gathered automatically from Wikipedia. We explored alternative topic translation methods using these resources. Our results indicate that extending machine translation tools using automatically generated domainspecific translation lexicons can provide improved CLIR effectiveness for this task
Discrete mechanics Based on Finite Element Methods
Discrete Mechanics based on finite element methods is presented in this
paper. We also explore the relationship between this discrete mechanics and
Veselov discrete mechanics. High order discretizations are constructed in terms
of high order interpolations.Comment: 14 pages, 0 figure
- …