A Novel Frank-Wolfe Algorithm. Analysis and Applications to Large-Scale SVM Training

Recently, there has been a renewed interest in the machine learning community for variants of a sparse greedy approximation procedure for concave optimization known as {the Frank-Wolfe (FW) method}. In particular, this procedure has been successfully applied to train large-scale instances of non-linear Support Vector Machines (SVMs). Specializing FW to SVM training has allowed to obtain efficient algorithms but also important theoretical results, including convergence analysis of training algorithms and new characterizations of model sparsity. In this paper, we present and analyze a novel variant of the FW method based on a new way to perform away steps, a classic strategy used to accelerate the convergence of the basic FW procedure. Our formulation and analysis is focused on a general concave maximization problem on the simplex. However, the specialization of our algorithm to quadratic forms is strongly related to some classic methods in computational geometry, namely the Gilbert and MDM algorithms. On the theoretical side, we demonstrate that the method matches the guarantees in terms of convergence rate and number of iterations obtained by using classic away steps. In particular, the method enjoys a linear rate of convergence, a result that has been recently proved for MDM on quadratic forms. On the practical side, we provide experiments on several classification datasets, and evaluate the results using statistical tests. Experiments show that our method is faster than the FW method with classic away steps, and works well even in the cases in which classic away steps slow down the algorithm. Furthermore, these improvements are obtained without sacrificing the predictive accuracy of the obtained SVM model.Comment: REVISED VERSION (October 2013) -- Title and abstract have been revised. Section 5 was added. Some proofs have been summarized (full-length proofs available in the previous version

Students’ Perceptions of Excellence in Chilean High-Performing Public Schools

This paper aims to analyze how students attending six of the most prestigious, selective, and high-performing public schools in Chile perceive the concept of excellence and what factors influence their perceptions. A survey was administered to 1,828 students enrolled in 11th and 12th grade. The results show that students share a multidimensional idea of excellence. Five dimensions are identified but, according to students’ perceptions, there were two constructs that stood out the most: “effort and self-improvement’” and ‘”social commitment and thoughtfulness.” We find that variables such as expectations about the future and perceptions about schools explain the dissimilar ideas of excellence shared by students. This research gives voice to students on a current topic of the educational agenda –the concept of excellence– and invites researchers to re-think this construct from perspectives other than academic achievement

Beef cattle and sheep systems management: Computer tools to design and evaluate productive scenarios

The increase in the human population and its consumption of animal protein have led to greater complexity in defining integrative practices to develop efficient production systems. The biological and economic sustainability of livestock systems can be focused on two lines: the increase in the efficiency of resource use with an internal sufficiency of the system and the structuring of functional integral systems. Market liberalization, changing customer expectations, technological discontinuities, and global competition cause the sources of competitive advantage to shift, forcing companies to continually respond to the demands of a dynamic environment. The adoption of a quality-oriented management model is one of the alternatives that has been most successful in facing the challenges of this global and competitive environment. However, the orientation towards quality generally requires innovations that must be evaluated to verify if they create value in the company. Value creation assessment is a concept that has not been applied in-depth in the bovine and sheep production sector and is probably what explains the reluctance of producers to adopt innovative technological alternatives. Value creation is related to the approach with which the objectives of the company are approached, which have evolved from a single objective, which is the maximization of profit, to the most recent one in which the coexistence of a plurality of objectives is recognized. This diversity of objectives can be integrated into one, which is the maximization of the company's value in the market

Signatures of the Galactic bar in high-order moments of proper motions measured by Gaia

Our location in the Milky Way provides an exceptional opportunity to gain insight on the galactic evolution processes, and complement the information inferred from observations of external galaxies. Since the Milky Way is a barred galaxy, the study of motions of individual stars in the bulge and disc is useful to understand the role of the bar. The Gaia mission enables such study by providing the most precise parallaxes and proper motions to date. In this theoretical work, we explore the effects of the bar on the distribution of higher-order moments --the skewness and kurtosis-- of the proper motions by confronting two simulated galaxies, one with a bar and one nearly axisymmetric, with observations from the latest Gaia data release (GaiaDR2). We introduce the code ASGAIA to account for observational errors of Gaia in the kinematical structures predicted by the numerical models. As a result, we find clear imprints of the bar in the skewness distribution of the longitudinal proper motion $\mu_\ell$ in GaiaDR2, as well as other features predicted for the next Gaia data releases.Comment: 11 pages, 9 figures, accepted in A&

The simulation models. A supporting tool for the livestock management

The way through which agricultural production has evolved is analyzed with a new paradigm which is not to produce more or to just produce in a profitable way, but to produce in agreement with the environment while creating an additional value for the agricultural enterprise. An experiment using a simulation model designed for dual purpose cattle in Colombia was carried out and its capacity for differentiating the equilibrium points of the productive system was analyzed thus demonstrating the situations when additionals values for the enterprise are created or destroyed

La producción de tesis de antropología en la Universidad Academia de Humanismo Cristiano. Aproximación a algunas de sus características

Intentando contribuir a la reflexión en torno a la producción de conocimiento en las antropologías del sur, este artículo representa un avance de resultados y tiene por objeto realizar una acercamiento descriptivo al quehacer de las ciencias antropológicas en Chile a partir de datos preliminares de un trabajo de sistematización y análisis de las tesis de grado de la Escuela de Antropología de la Universidad Academia de Humanismo Cristiano, realizadas en un período de veinte años (1998 y 2018). A partir de sus ejes temáticos, así como las zonas geográficas involucradas, se establece cierta relación entre las bases que configuraron el proyecto de formación antropológica de la escuela analizada y la producción de conocimientos reflejadas en las tesis de grado

La producción de tesis de antropología en la Universidad Academia de Humanismo Cristiano. Aproximación a algunas de sus características

Intentando contribuir a la reflexión en torno a la producción de conocimiento en las antropologías del sur, este artículo representa un avance de resultados y tiene por objeto realizar una acercamiento descriptivo al quehacer de las ciencias antropológicas en Chile a partir de datos preliminares de un trabajo de sistematización y análisis de las tesis de grado de la Escuela de Antropología de la Universidad Academia de Humanismo Cristiano, realizadas en un período de veinte años (1998 y 2018).  A partir de sus ejes temáticos, así como las zonas geográficas involucradas, se establece cierta relación entre las bases que configuraron el proyecto de formación antropológica de la escuela analizada y la producción de conocimientos reflejadas en las tesis de grad

An approach for the analysis of news during COVID-19 in the Chubut province

The present work exposes preliminary results on utilizing web scraping and data mining techniques to analyze news articles published during the COVID-19 pandemic in the Chubut province. Analysis of extracted articles was made using Latent Dirichlet Allocation obtaining promising results.Facultad de Informátic

El tema / La marca

Quienes ejercemos la docencia debemos brindarles a nuestros alumnos herramientas conceptuales y metodológicas que les permitan desarrollarse en escenarios futuros, que aún no conocemos y que tendrán profundas diferencias con los anteriores y actuales. Por ello, necesitamos fomentar el pensamiento complejo (Morin, 1990), considerando la multiplicidad de causas y efectos que se ponen en juego en los procesos de identificación, de comunicación y de consumo. El texto discute el concepto y los usos de "marca".Facultad de Arte

AVALIAÇÃO ANTROPOMÉTRICA E POR BIOIMPEDÂNCIA DE UM PROGRAMA DE EDUCAÇÃO NUTRICIONAL PARA ESCOLARES NA FAIXA ETÁRIA DE 7-14 ANOS DURANTE O PERÍODO DE 10 MESES

Over the past several decades, an increasing prevalence of excessive weight has been observed among children. Considering the importance of schools in promoting health, the implementation of individualized educational interventions in a school setting is necessary. The present study aimed to determine the influence of a nutritional education program in promoting the healthy eating habits and nutritional status of school-aged students. A total of 416 children and adolescents between 7 and 14 years of age who were enrolled in 2 complementary public schools were evaluated. A 10- month intervention in one of the schools was based on a nutritional education program targeting the students, legal guardians and school staff and involved substantial changes in the school meal menu. Weight, height, BMI, lean mass and body fat mass were evaluated in both the intervention (school 1) and the control (school 2) groups. At the beginning of the study, both school 1 and 2 exhibited a prevalence of overweight (34.0% and 28%, respectively) and obese students (16.9% and 10.4%, respectively); obesity was significantly reduced by the end of the study (p = 0.001). The growth of the students was considered normal for the age range in both schools, although it was slightly larger in school 1 (p = 0.04). Measurements of body composition, which were collected using bioelectrical impedance, indicated an increase in lean mass in both schools (p < 0.01) with an increase in body fat mass being observed only in school 2 (p = 0.01). These results, which are related to a significant reduction of the BMI, a change in bodily proportions and an increase in height growth for the students of school 1, indicate the beneficial aspects of the adopted diet.[N