Papers by victor alfonso alvarez garcia
Un asistente profesional en metodologías para la moderna ingeniería de software
Revista Ean, Jul 20, 2013
Como resultado de un proceso de investigación iniciado en la Universidad Nacional de Colombia, co... more Como resultado de un proceso de investigación iniciado en la Universidad Nacional de Colombia, continuado en la Escuela de Administración de Negocios EAN y en la Universidad Distrital F.J.C., se presenta un asistente o tutor inteligente para el aprendizaje del ciclo innovado de la metodología de ingeniería de software, a partir del modelo propuesto por James Martín, apoyado por bases de conocimientos...
Las crisis y sus respuestas en la historia contemporánea : VI Ciclos de Conferencias, Cine e Historia
Artículos de tradición liberal
El pintor Vicente Salvador Gómez (Valencia, 1637-1678)
Revista Colombiana De Cirugia, Sep 1, 2014
Analisis Financiero Aplicado a Una Empresa De La Industria Vidriera
Seguimiento y gestión del rebeco cantábrico en Galicia
The Cantabrian chamois became extinct in Galicia at the end of the 1960’s in the Ancares Mountain... more The Cantabrian chamois became extinct in Galicia at the end of the 1960’s in the Ancares Mountains, in the border between Lugo and León provinces, and in the northern watershed of Peña Tevinca mountain, near the border between Ourense, León and Zamora provinces. In the middle of 1980’s chamois was reintroduced in the Game Preserve of Ancares Leoneses using animals from Riaño (León). It is not possible to make an accurate estimation of the number of chamois that live in Galicia nowadays, as they roam between Galicia and the adjacent León province, but they might exceed one hundred individuals and they are increasing. There is also a small number of about twenty chamois in a large fenced area in the Invernadeiro mountains (Ourense, Galicia).
HiSTOReLo. Revista de Historia Regional y Local, 2014
Lecture Notes in Computer Science
We present an experimental study of two versions of a seconddegree iterative method applied to th... more We present an experimental study of two versions of a seconddegree iterative method applied to the resolution of the sparse linear systems related to the 3D multi-group time-dependent Neutron Diffusion Equation (TNDE), which is important for studies of stability and security of nuclear reactors. In addition, the second-degree iterative methods have been combined with an adaptable technique, in order to improve their convergence and accuracy. The authors consider that second-degree iterative methods can be applied and extended to the study of transient analysis with more than two energy groups and they might represent a saving in spatial cost for nuclear core simulations. These methods have been coded in PETSc [1][2][3].
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2008
Sphere-Decoding (SD) methods are branch-and-bound-like techniques used for optimal detection of d... more Sphere-Decoding (SD) methods are branch-and-bound-like techniques used for optimal detection of digital communications signals over in wireless MIMO (Multiple input Multiple Output) channels. These methods look for the optimal solution in a tree of partial solutions; the size of the tree depends on the parameters of the problem (dimension of the channel matrix, cardinality of the alphabet), and such search can be much more expensive depending on these parameters. This search often has to be carried out in real time. This paper presents parallel versions of the Sphere-Decoding method for different parallel architectures with the goal of reducing the computation time.
A deterministic lower bound for the radius in sphere decoding search
The 2010 International Conference on Advanced Technologies for Communications, 2010
... Victor M. Garcia!, Sandra Roger2, Rafael A. Trujillo!, Antonio M. Vidal!, Alberto Gonzalez2 1... more ... Victor M. Garcia!, Sandra Roger2, Rafael A. Trujillo!, Antonio M. Vidal!, Alberto Gonzalez2 1 Department of Information Systems and Computation 2Institute of Telecommunications and Multimedia Applications ... where H+ = HH (HHH)-l is the pseudoinverse of the channel matrix. ...
A gradient-based ordering for MIMO decoding
2009 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT), 2009
The ordering of the columns of the channel matrix has a deep impact in the performance of many de... more The ordering of the columns of the channel matrix has a deep impact in the performance of many decoding methods for MIMO problems. The most popular algorithms for computation of good orderings use as only input the channel matrix (such as the V-BLAST ordering). However, there are other interesting algorithms that compute the ordering as a function of the matrix
Compatibility of Scalapack with the Discrete Wavelet Transform
Lecture Notes in Computer Science, 2007
Computational Science – ICCS 2006, 2006
This paper is focused in the parallelization of Direct Search Optimization methods, which are par... more This paper is focused in the parallelization of Direct Search Optimization methods, which are part of the family of derivative-free methods. These methods are known to be quite slow, but are easily parallelizable, and have the advantage of achieving global convergence in some problems where standard Newton-like methods (based on derivatives) fail. These methods have been tested with the Inverse Additive Singular Value Problem, which is a difficult highly nonlinear problem. The results obtained have been compared with those obtained with derivative methods; the efficiency of the parallel versions has been studied.
Nursing Administration Quarterly, 2011
The changing framework of today's health care system requires leaders to be increasingly innovati... more The changing framework of today's health care system requires leaders to be increasingly innovative in how they approach their daily functions and responsibilities. Sustaining and advancing a level of innovation that already exists can be challenging for health care administrators with the demands of time and resource limitations. Using collaboration to bring new-age teaching and disciplines to front-line leadership, one hospital was able to reinvigorate a culture of innovation through multiple levels and disciplines of the organization. The Innovation Certification Course provided nursing leaders and other managers' an evidence-drive approach, new principles and useful strategies of innovative leadership and graduate program education.
Journal of Parallel and Distributed Computing, 2011
In a previous paper (Vidal et al., 2008, [21]), we presented a parallel solver for the symmetric ... more In a previous paper (Vidal et al., 2008, [21]), we presented a parallel solver for the symmetric Toeplitz eigenvalue problem, which is based on a modified version of the Lanczos iteration. However, its efficient implementation on modern parallel architectures is not trivial. In this paper, we present an efficient implementation on multicore processors which takes advantage of the features of this architecture. Several optimization techniques have been incorporated to the algorithm: improvement of Discrete Sine Transform routines, utilization of the Gohberg-Semencul formulas to solve the Toeplitz linear systems, optimization of the workload distribution among processors, and others. Although the algorithm follows a distributed memory parallel programming paradigm that is led by the nature of the mathematical derivation, special attention has been paid to obtaining the best performance in multicore environments. Hybrid techniques, which merge OpenMP and MPI, have been used to increase the performance in these environments. Experimental results show that our implementation takes advantage of multicore architectures and clearly outperforms the results obtained with LAPACK or ScaLAPACK.
Journal de Théorie des Nombres de Bordeaux, 2013
International Journal for Numerical Methods in Engineering, 2006
In this paper, a special purpose algorithm for solving large eigenvalue problems based on the Lan... more In this paper, a special purpose algorithm for solving large eigenvalue problems based on the Lanczos method is successfully applied to an engineering problem: the electromagnetic analysis and design of passive waveguide devices. For dealing with such complex problems, the boundary integral-resonant mode expansion (BI-RME) technique has been recently proposed. This technique solves integral equations (IEs) through the well-known method of moments (MoM), thus leading to structured eigenvalue problems. These problems frequently become very large when solving complex arbitrary geometries with high accuracy. In such cases, the eigenvalue problem cannot be efficiently solved with standard methods by means of personal computers, essentially due to CPU time and memory allocation requirements. In this paper, we propose an alternative technique, based on the Lanczos method, for the fast and accurate solution of large BI-RME generalized eigenvalue problems. The novel theoretical aspects of this approach, as well as the impact on the original BI-RME formulation, are described. Comparative benchmarks are also successfully presented for the full-wave analysis and design of real passive microwave devices.
Surgical treatment of proximal ruptures of the rectus femoris in professional soccer players
Archives of Orthopaedic and Trauma Surgery, 2011
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Papers by victor alfonso alvarez garcia