Splitting methods for constrained quadratic programs in data analysis

This paper is concerned with the numerical solution of a linearly constrained quadratic programming problem by methods that use a splitting of the objective matrix. We present an acceleration step for a general splitting algorithm and we establish the convergence of the resulting accelerated scheme. We report the results of numerical experiments arising in constrained bivariate interpolation to evaluate the efficiency of this acceleration technique for a particular splitting of the objective matrix and for the corresponding extrapolated for

Splitting methods for quadratic optimization in data analysis

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Parallel Solution of Large-Scale Quadratics Programs

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Variable Projection Methods for Large-Scale Quadratic Optimization in Data Analysis Applications

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Splitting Methods and Parallel solution of Constrained Quadratic Programs

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A minimization method for the solution of large symmetric eigenproblems

This paper concerns with the solution of a special eigenvalue problem for a large sparse symmetric matrix by a fast convergent minimization method. A theoretical analysis of the method is developed; it is proved that is convergent with a convergence rate of fourth order. This minimization method requires to solve a sequence of equality-constrained least squares problems that become increasingly ill-conditioned, as the solution of eigenvalue problem is approached. A particular attention has been addressed to this question of ill-conditioning for the practical application of the method. Computational experiments carried out on Cray C90 show the behaviour of this minimization method as accelerating technique of the inverse iteration method. Also a comparison with the scaled Newton method has been done

An assessment of bone diagenesis using scanning electron microscopy (SEM): analytic approaches a

El objetivo del presente trabajo es realizar una revisión de las aproximaciones analíticas aplicables al estudio de la diagénesis ósea -dentro del campo más amplio de la tafonomía- que se basan en el uso de la microscopía electrónica de barrido (MEB). Para ello, se presenta a) una síntesis de los conocimientos actuales acerca de los procesos diagenéticos que afectan a la integridad histológica de los restos óseos, tanto humanos como faunísticos, en depósitos sedimentarios terrestres; b) una exposición abreviada de los principios generales de la microscopía electrónica, particularmente de la MEB y c) un comparación de las diferencias -en cuanto a requerimientos, información obtenible y ventajas/desventajas asociadas- entre los análisis centrados en los dos principales tipos de imágenes producidas por un MEB, es decir, las de electrones retrodispersados y las de electrones secundarios. Se concluye que, dada la disponibilidad relativamente amplia de esta tecnología, el factor crítico para una incorporación más activa delMEB en la investigación arqueológica y bioantropológica no es el acceso al equipamiento, sino la apropiada identificación de los problemas de investigación a resolver, así como la adecuada selección y ejecución de las técnicas de observación y análisis a emplear. PALABRAS CLAVE hueso; alteración histológica; imágenes The aim of this paper is to review analytic approaches to bone diagenesis based on the use of scanning electron microscopy (SEM). In order to do this, we present a) a synthesis of current knowledge about diagenetic processes affecting the histological integrity of human and faunal skeletal remains in terrestrial sedimentary deposits; b) a brief description of the general principles of electron microscopy, particularly of SEM, and c) a comparison of the main differences -in terms of requirements, recoverable information, and associated pros and cons- between analyses centered on the use of either of the two main kinds of images produced by a SEM, i.e., backscattered electron images and secondary electron images. It is concluded that, given the relatively wide availability of this technology, the critical factor to a more active involvement of SEM in archaeological and bioanthropological research is not the access to equipment, but the correct identification of the research problems to be solved, as well as the proper selection and implementation of the observational and analytical techniques to be employed. KEY WORDS bone; histological alteration; imagesThe aim of this paper is to review analytic approaches to bone diagenesis based on the use of scanning electron microscopy (SEM). In order to do this, we present a) a synthesis of current knowledge about diagenetic processes affecting the histological integrity of human and faunal skeletal remains in terrestrial sedimentary deposits; b) a brief description of the general principles of electron microscopy, particularly of SEM, and c) a comparison of the main differences -in terms of requirements, recoverable information, and associated pros and cons- between analyses centered on the use of either of the two main kinds of images produced by a SEM, i.e., backscattered electron images and secondary electron images. It is concluded that, given the relatively wide availability of this technology, the critical factor to a more active involvement of SEM in archaeological and bioanthropological research is not the access to equipment, but the correct identification of the research problems to be solved, as well as the proper selection and implementation of the observational and analytical techniques to be employed. KEY WORDS bone; histological alteration; image

Evaluación de la diagénesis ósea mediante el uso de microscopía electrónica de barrido (MEB): aproximaciones analíticas aplicables a muestras arqueológicas / An assessment of bone diagenesis using scanning electron microscopy (SEM): analytic approaches a

El objetivo del presente trabajo es realizar una revisión de las aproximaciones analíticas aplicables al estudio de la diagénesis ósea -dentro del campo más amplio de la tafonomía- que se basan en el uso de la microscopía electrónica de barrido (MEB). Para ello, se presenta a) una síntesis de los conocimientos actuales acerca de los procesos diagenéticos que afectan a la integridad histológica de los restos óseos, tanto humanos como faunísticos, en depósitos sedimentarios terrestres; b) una exposición abreviada de los principios generales de la microscopía electrónica, particularmente de la MEB y c) un comparación de las diferencias -en cuanto a requerimientos, información obtenible y ventajas/desventajas asociadas- entre los análisis centrados en los dos principales tipos de imágenes producidas por un MEB, es decir, las de electrones retrodispersados y las de electrones secundarios. Se concluye que, dada la disponibilidad relativamente amplia de esta tecnología, el factor crítico para una incorporación más activa delMEB en la investigación arqueológica y bioantropológica no es el acceso al equipamiento, sino la apropiada identificación de los problemas de investigación a resolver, así como la adecuada selección y ejecución de las técnicas de observación y análisis a emplear. PALABRAS CLAVE hueso; alteración histológica; imágenes The aim of this paper is to review analytic approaches to bone diagenesis based on the use of scanning electron microscopy (SEM). In order to do this, we present a) a synthesis of current knowledge about diagenetic processes affecting the histological integrity of human and faunal skeletal remains in terrestrial sedimentary deposits; b) a brief description of the general principles of electron microscopy, particularly of SEM, and c) a comparison of the main differences -in terms of requirements, recoverable information, and associated pros and cons- between analyses centered on the use of either of the two main kinds of images produced by a SEM, i.e., backscattered electron images and secondary electron images. It is concluded that, given the relatively wide availability of this technology, the critical factor to a more active involvement of SEM in archaeological and bioanthropological research is not the access to equipment, but the correct identification of the research problems to be solved, as well as the proper selection and implementation of the observational and analytical techniques to be employed. KEY WORDS bone; histological alteration; image