2,347 research outputs found
Bounded geometry and leaves
The main theorem states that any complete connected Riemannian manifold of
bounded geometry can be isometrically realized as a leaf with trivial holonomy
in a compact Riemannian foliated space.Comment: 21 pages. To appear in Math. Nachr. arXiv admin note: text overlap
with arXiv:1408.477
A universal Riemannian foliated space
It is proved that the isometry classes of pointed connected complete
Riemannian -manifolds form a Polish space, , with
the topology described by the convergence of manifolds. This space
has a canonical partition into sets defined by varying the distinguished point
into each manifold. The locally non-periodic manifolds define an open dense
subspace ,
which becomes a foliated space with the restriction of the canonical
partition. Its leaves without holonomy form the subspace
defined by the non-periodic manifolds. Moreover the leaves have a natural
Riemannian structure so that becomes a
Riemannian foliated space, which is universal among all sequential Riemannian
foliated spaces satisfying certain property called covering-continuity.
is used to characterize the realization
of complete connected Riemannian manifolds as dense leaves of
covering-continuous compact sequential Riemannian foliated spaces.Comment: 32 pages. Published in Topology Appl., 198 (2016), 47-8
Unusual Kondo physics in a Co impurity atom embedded in noble-metal chains
We analyze the conduction bands of the one dimensional noble-metal chains
that contain a Co magnetic impurity by means of ab initio calculations. We
compare the results obtained for Cu and Ag pure chains, as well as O doped Cu,
Ag and Au chains with those previously found for Au pure chains. We find
similar results in the case of Cu and Au hosts, whereas for Ag chains a
different behavior is obtained. Differences and similarities among the
different systems are analyzed by comparing the electronic structure of the
three noble-metal hosts. The d-orbitals of Cu chains at the Fermi level have
the same symmetry as in the case of Au chains. These orbitals hybridize with
the corresponding ones of the Co impurity, giving rise to the possibility of
exhibiting a two-channel Kondo physics.Comment: Accepted in IEEE Trans. Magn. - April 201
RECOGNITION OF HUMAN MOVEMENT PATTERNS
INTRODUCTION - Since a few years ago computer science means an important sup port to biomechanical analysis. Whenever a lot of calculations are to be made, and the value of different parameters like mechanical variables are needed, the advantages of using computers are clear. However a bottleneck is present in data acquisition process for cinematic analysis from video sequence. Traditionally this task is performed like a manual process: user of computer systems must mark, for each frame, some articular points (about 20-21 ) by means of an optical pencil or using a mouse on the computer display once image has been digitalized. This is a routinary task and takes a lot of time. For example, for three seconds of movement, we probably need to process about 150 frames and, for each of them, to perform a digitalizing process. Recently new approaches are used to allow an automatic recognition. These approaches are based on the use of body optical sensors. Recognition process is easier because we only see several single points in the screen (under special environment conditions). However, these approaches are no applicable in real situations (i.e. competitions) which are the most interesting moments for analysis. What we propose here is an attempt to make an automatic system for data acquisition process from video sequences in sport environments and, as a general rule, for the analysis of human movement. We must take into account that the complexity of recognition process is lowered if we are working into a very narrow domain, like cyclic movements with 2D analysis (i.e. path of legs in some kinds of running). Nevertheless, our approach can be transferred to movements with 3D analysis if tridimensional reconstruction from human shapes has been performed. The process that our system will perform on each frame includes: . Digital image pre-processing, Edge sharpening, contrast adjust and filling of areas of interest. . If results are on satisfactoy (e.g. incomplete shapes), an Artificial Neural Network is used in order to predict total pattern, using previous frames or information available in a sportmen customized database containing antrophometric data and cinematic pattern of movement. . Last step is an intelligent matching between articular segments included in database (invariables botn with a 3D analysis and with a 2D analysis under specific features mentioned above) and human shapes obtained from previous steps. RESULTS - First phase relating to image recognition in laboratory conditions (high contrast) has been performed and the difference between manual articular coordenates and automatic acquisition was about zero-two units. CONCLUSION - The system we propose can help to biomechanics to reduce a lot the time destinated to perform data acquisition. Several hours would be changed to some minutes without human assist. REFERENCES R. J. Schalkoff, (1988) Digital lmage Processing and Computer Vision. John Wiley and Sons Inc. L.J. Galbiati, (1988) Machine Vision and Digital lmage Processing Fundamentals. Prentice-Hall International. C.H. Chen, (1993) Handbook of Pattern Recognition and Computer Vision. World Scientific
Pigment Epithelium-Derived Factor – An Angiostatic Factor with a Broader Function in Melanoma
Capítulo 8: Open Access.Supported by grants Ministerio de Educacion y Ciencia SAF2007-62292 and SAF2010-19256 to BJ. AFB has been supported by a CSIC-JAE fellowship and JLO by a SAF2007-62292 contract.Peer Reviewe
Aperiodic Colorings and Dynamics
A graph coloring is strongly aperiodic if every colored graph in its hull has no automorphisms. The talk will describe a method to define strongly aperiodic colorings on graphs with bounded degree. This also provides an optimal bound for the strongly distinguishing number of a graph. Then some applications to the theory of foliated spaces and to tilings will be discussed
- …