Reports de recerca
http://hdl.handle.net/2117/1861
Wed, 21 Feb 2018 11:44:36 GMT2018-02-21T11:44:36ZMultisided patches
http://hdl.handle.net/2117/97925
Multisided patches
Pla García, Núria; Vigo Anglada, Marc; Cotrina Navau, Josep
We present a method to construct a patch of parametric surface of degree k + 1 that lls a n-sided hole, with n bigger than 2, and whose boundary coincides with a B-Spline, thus, the resulting patch can be easily connected with given B-Spline surfaces with xed continuity conditions. The method is inspired on a generic approach to construct free form surfaces, which gives a family of practical schemes to design surfaces from an arbitrary given mesh, using the di erentiable manifold theory. The input is a star shaped mesh which describes a generic n-hole and a surface in a neighborhood of the hole. The main advantages of the method are the following: arbitrary order k continuity conditions can be imposed; the involved hole can have an arbitrary number of sides and arbitrary shape (convex or not); the simplicity of the construction process gives an easy and exible method; and nally, the surface near the boundary is a B-Spline with piecewise uniform knot sequences and whose control points are vertices of the given mesh; both knot sequences and control points are easily computed. Implementation details to evaluate a surface point are given, showing that the de Boor algorithm can be exploited for efficiency.
Fri, 09 Dec 2016 10:50:42 GMThttp://hdl.handle.net/2117/979252016-12-09T10:50:42ZPla García, NúriaVigo Anglada, MarcCotrina Navau, JosepWe present a method to construct a patch of parametric surface of degree k + 1 that lls a n-sided hole, with n bigger than 2, and whose boundary coincides with a B-Spline, thus, the resulting patch can be easily connected with given B-Spline surfaces with xed continuity conditions. The method is inspired on a generic approach to construct free form surfaces, which gives a family of practical schemes to design surfaces from an arbitrary given mesh, using the di erentiable manifold theory. The input is a star shaped mesh which describes a generic n-hole and a surface in a neighborhood of the hole. The main advantages of the method are the following: arbitrary order k continuity conditions can be imposed; the involved hole can have an arbitrary number of sides and arbitrary shape (convex or not); the simplicity of the construction process gives an easy and exible method; and nally, the surface near the boundary is a B-Spline with piecewise uniform knot sequences and whose control points are vertices of the given mesh; both knot sequences and control points are easily computed. Implementation details to evaluate a surface point are given, showing that the de Boor algorithm can be exploited for efficiency.N-sided patches with B-spline boundaries
http://hdl.handle.net/2117/97827
N-sided patches with B-spline boundaries
Cotrina Navau, Josep; Pla García, Núria; Vigo Anglada, Marc
We present a method to construct a patch of parametric surface of
degree k+1 that fills a n-sided hole, with bigger than 2, and whose
boundary coincides with a B-Spline, thus, the resulting patch can be
easily connected with given B-Spline surfaces with fixed continuity
conditions. The method is based on the generic approach by the same
authors to con-struct free form surfaces, which gives a family of
practical schemes to design surfaces from an arbitrary given mesh,
using the differentiable manifold the-ory. The proposal uses a star
shaped mesh which describes a generic n-hole and a surface in a
neighborhood of the hole. From this mesh, a set of charts is defined,
one associated to each vertex or face of the mesh, depending on the
parity of the input parameter k. A basis function and a control point
is defined from each chart, and the surface is obtained as a
baricentric combination of the control points using the defined basis
functions. The main advantages of the method are the following:
arbitrary order k continuity conditions can be imposed; the involved
hole can have an arbitrary number of sides and arbitrary shape (convex
or not) the simplicity of the construction process gives an easy and
flexible method; and finally, the surface near the boundary is a
B-Spline with piecewise uniform knot sequences and whose control
points are vertices of the given mesh. Implementation details to
evaluate a surface point are given, showing that the de Boor algorithm
can be exploited for efficiency.
Wed, 07 Dec 2016 10:03:03 GMThttp://hdl.handle.net/2117/978272016-12-07T10:03:03ZCotrina Navau, JosepPla García, NúriaVigo Anglada, MarcWe present a method to construct a patch of parametric surface of
degree k+1 that fills a n-sided hole, with bigger than 2, and whose
boundary coincides with a B-Spline, thus, the resulting patch can be
easily connected with given B-Spline surfaces with fixed continuity
conditions. The method is based on the generic approach by the same
authors to con-struct free form surfaces, which gives a family of
practical schemes to design surfaces from an arbitrary given mesh,
using the differentiable manifold the-ory. The proposal uses a star
shaped mesh which describes a generic n-hole and a surface in a
neighborhood of the hole. From this mesh, a set of charts is defined,
one associated to each vertex or face of the mesh, depending on the
parity of the input parameter k. A basis function and a control point
is defined from each chart, and the surface is obtained as a
baricentric combination of the control points using the defined basis
functions. The main advantages of the method are the following:
arbitrary order k continuity conditions can be imposed; the involved
hole can have an arbitrary number of sides and arbitrary shape (convex
or not) the simplicity of the construction process gives an easy and
flexible method; and finally, the surface near the boundary is a
B-Spline with piecewise uniform knot sequences and whose control
points are vertices of the given mesh. Implementation details to
evaluate a surface point are given, showing that the de Boor algorithm
can be exploited for efficiency.Towards free form surfaces
http://hdl.handle.net/2117/97654
Towards free form surfaces
Cotrina Navau, Josep; Pla García, Núria; Vigo Anglada, Marc
A theoretical approach to construct free form surfaces is presented. We
develop the conceps that arise when a free form surface is generated by
tracing a mesh, using differentiable manifold theory, and generalizing
the B-spline scheme. This approach allows to define a family of
practical schemes.
Thu, 01 Dec 2016 18:18:08 GMThttp://hdl.handle.net/2117/976542016-12-01T18:18:08ZCotrina Navau, JosepPla García, NúriaVigo Anglada, MarcA theoretical approach to construct free form surfaces is presented. We
develop the conceps that arise when a free form surface is generated by
tracing a mesh, using differentiable manifold theory, and generalizing
the B-spline scheme. This approach allows to define a family of
practical schemes.Free form surfaces
http://hdl.handle.net/2117/95949
Free form surfaces
Cotrina Navau, Josep; Pla García, Núria
A method to construct continuous order k surfaces of arbitrary
topological type by tracing a mesh that represents a 2-manifold is
presented. The presented approach constructs the surface from a
collection of pieces which overlap, using the known technology of
manifolds. The surface is built from the given mesh and two arbitrary
input parameters, k and n. The value of k gives the continuity of the
resulting surface and n controls the local influence of the vertices
of the mesh. The presented scheme generalizes the B-spline approach
in terms of manifolds. The surface that arises from regular zones of
the mesh is a tensorial product B-spline surface. For the rest, that
is, the irregular zones, the surface has the following good
properties: it is k continuous, affine invariant, the convex hull
property is guaranteed, and it has local control. The algorithm is
simple and efficient in time and space.
Wed, 09 Nov 2016 12:52:04 GMThttp://hdl.handle.net/2117/959492016-11-09T12:52:04ZCotrina Navau, JosepPla García, NúriaA method to construct continuous order k surfaces of arbitrary
topological type by tracing a mesh that represents a 2-manifold is
presented. The presented approach constructs the surface from a
collection of pieces which overlap, using the known technology of
manifolds. The surface is built from the given mesh and two arbitrary
input parameters, k and n. The value of k gives the continuity of the
resulting surface and n controls the local influence of the vertices
of the mesh. The presented scheme generalizes the B-spline approach
in terms of manifolds. The surface that arises from regular zones of
the mesh is a tensorial product B-spline surface. For the rest, that
is, the irregular zones, the surface has the following good
properties: it is k continuous, affine invariant, the convex hull
property is guaranteed, and it has local control. The algorithm is
simple and efficient in time and space.Modelling surfaces from planar irregular meshes
http://hdl.handle.net/2117/84371
Modelling surfaces from planar irregular meshes
Cotrina Navau, Josep; Pla García, Núria
We present a method for constructing surfaces from irregular control
meshes that can be embedded in the plane. This method results from a
generalization of B-Splines using the known technology of
manifolds. The resulting surface can be built with {GC}^k
continuity.
The presented approach constructs the surface from a collection of
pieces which overlap. This method can be generalized to arbitrary
meshes to generate general closed surfaces or surfaces with handles by
application of an analogous reasoning locally in a general case.
Tue, 15 Mar 2016 12:17:37 GMThttp://hdl.handle.net/2117/843712016-03-15T12:17:37ZCotrina Navau, JosepPla García, NúriaWe present a method for constructing surfaces from irregular control
meshes that can be embedded in the plane. This method results from a
generalization of B-Splines using the known technology of
manifolds. The resulting surface can be built with {GC}^k
continuity.
The presented approach constructs the surface from a collection of
pieces which overlap. This method can be generalized to arbitrary
meshes to generate general closed surfaces or surfaces with handles by
application of an analogous reasoning locally in a general case.Weighted contention and interference routing metric (WCIM): Research Report
http://hdl.handle.net/2117/8121
Weighted contention and interference routing metric (WCIM): Research Report
Catalán Cid, Miguel; Ferrer, Josep Lluís; Gómez Montenegro, Carlos; Paradells Aspas, Josep
Contention- and Interference-Aware Flow-based Routing in Wireless Mesh Networks: design and evaluation of a novel routing metric
Report 1: Analysis of WCIM model
Report 2: Simulations
Mon, 12 Jul 2010 09:15:07 GMThttp://hdl.handle.net/2117/81212010-07-12T09:15:07ZCatalán Cid, MiguelFerrer, Josep LluísGómez Montenegro, CarlosParadells Aspas, JosepContention- and Interference-Aware Flow-based Routing in Wireless Mesh Networks: design and evaluation of a novel routing metric
Report 1: Analysis of WCIM model
Report 2: SimulationsLa Internet del Futur: Anàlisi retrospectiva, reflexió i posicionament estratègic
http://hdl.handle.net/2117/6750
La Internet del Futur: Anàlisi retrospectiva, reflexió i posicionament estratègic
Serra Hurtado, Arturo; Alcober Segura, Jesús Ángel; Cervelló Pastor, Cristina; Domingo Pascual, Jordi; Fernández, Gabriel; Junyent Giralt, Gabriel; Oliver, Miquel; Paradells Aspas, Josep; Sallent Ribes, Sebastián
Aquest treball té com a objectiu analitzar la situació actual de la Internet, per proposar noves alternatives i dibuixar un possible camí cap a la Internet del Futur. Aquesta anàlisi vol ser un punt de partida, un document de reflexió, que posicioni als agents locals i nacionals (entorns de la recerca, innovació i producció, i usuaris) en una situació capdavantera en la construcció del nou model econòmic i social del segle XXI.
El treball consta de dos grans apartats, una introducció descriptiva i conceptual del paper que juga la Internet i la seva projecció futura, i una segona part on es desdibuixen en mes profunditat les bases tecnològiques de la possible Internet del futur a partir de la realitat actual.
Mon, 22 Mar 2010 13:21:16 GMThttp://hdl.handle.net/2117/67502010-03-22T13:21:16ZSerra Hurtado, ArturoAlcober Segura, Jesús ÁngelCervelló Pastor, CristinaDomingo Pascual, JordiFernández, GabrielJunyent Giralt, GabrielOliver, MiquelParadells Aspas, JosepSallent Ribes, SebastiánAquest treball té com a objectiu analitzar la situació actual de la Internet, per proposar noves alternatives i dibuixar un possible camí cap a la Internet del Futur. Aquesta anàlisi vol ser un punt de partida, un document de reflexió, que posicioni als agents locals i nacionals (entorns de la recerca, innovació i producció, i usuaris) en una situació capdavantera en la construcció del nou model econòmic i social del segle XXI.
El treball consta de dos grans apartats, una introducció descriptiva i conceptual del paper que juga la Internet i la seva projecció futura, i una segona part on es desdibuixen en mes profunditat les bases tecnològiques de la possible Internet del futur a partir de la realitat actual.Available Admission Capacity Estimations in IEEE 802.11 Access Points
http://hdl.handle.net/2117/2045
Available Admission Capacity Estimations in IEEE 802.11 Access Points
García Villegas, Eduard
This technical report is intended to provide extended information about the Available Admission Capacity estimation mechanism for IEEE 802.11 cells previously presented. The original formulation has been revised in this paper avoiding unnecessary approximations. Furthermore, a comprehensive evaluation of the algorithm is also provided.
Thu, 29 May 2008 15:44:28 GMThttp://hdl.handle.net/2117/20452008-05-29T15:44:28ZGarcía Villegas, EduardThis technical report is intended to provide extended information about the Available Admission Capacity estimation mechanism for IEEE 802.11 cells previously presented. The original formulation has been revised in this paper avoiding unnecessary approximations. Furthermore, a comprehensive evaluation of the algorithm is also provided.