Comparing Cost Functions in Resource Analysis

Cost functions provide information about the amount of resources required to execute a program in terms of the sizes of input arguments. They can provide an upper-bound, a lower-bound, or the average-case cost. Motivated by the existence of a number of automatic cost analyzers which produce cost functions, we propose an approach for automatically proving that a cost function is smaller than another one. In all applications of resource analysis, such as resource-usage verification, program synthesis and optimization, etc., it is essential to compare cost functions. This allows choosing an implementation with smaller cost or guaranteeing that the given resource-usage bounds are preserved. Unfortunately, automatically generated cost functions for realistic programs tend to be rather intricate, defined by multiple cases, involving non-linear subexpressions (e.g., exponential, polynomial and logarithmic) and they can contain multiple variables, possibly related by means of constraints. Thus, comparing cost functions is far from trivial. Our approach first syntactically transforms functions into simpler forms and then applies a number of su!cient conditions which guarantee that a set of expressions is smaller than another expression. Our preliminary implementation in the COSTA system indicates that the approach can be useful in practic

Evolution of the European vocational training policy from the principles of 1963

The educational policy of the European Union can be divided into a number of distinct stages characterized by their social context. In each of them, they carried out different actions in education. Vocational training has been and is one of the most important aspects of these actions. That is why this article pretends to review the general principles which promoted the creation of a common policy on vocational training for the first time in the European Union in 1963. A critical interpretation of the review is also presented, based on its main axes (vision, goal, mission, purpose, guidelines, principles, strategies, working methods and tools) in order to help understand the influence of this principles on other european education policies since their inception to the present and their short-term impact at national levelLa política educativa de la Unión Europea se puede dividir en una serie de etapas bien definidas marcadas por su contexto social. En cada una de ellas se llevan a cabo diversas acciones en materia educativa. La formación profesional ha sido y es uno de los aspectos más relevantes de los que se ocupan esas acciones. Por ello, en este artículo se pretende analizar los principios generales que en 1963 impulsaron por primera vez la creación de una política común de formación profesional en la Unión Europea. Se presenta también una interpretación crítica del análisis realizado, en base a los ejes principales sobre los que se lleva a cabo el mismo (visión, meta, misión, finalidad, orientaciones, principios, estrategias, método de trabajo e instrumentos) con el objetivo de ayudar a comprender la influencia de estos principios en el resto de políticas educativas europeas desde su creación hasta la actualidad y su impacto a corto plazo a nivel naciona

On abstraction-carrying code and certificate-size reduction

Abstraction-Carrying Code (ACC) is a framework for mobile code safety in which the code supplier provides a program together with an abstraction (or abstract model of the program) whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certificate and its generation is carried out automatically by a fixed-point analyzer. The advantage of providing a (fixed-point) abstraction to the code consumer is that its validity is checked in a single pass (i.e., one iteration) of an abstract interpretation-based checker. A main challenge to make ACC useful in practice is to reduce the size of certificates as much as possible, while at the same time not increasing checking time. Intuitively, we only include in the certificate the information which the checker is unable to reproduce without iterating. We introduce the notion of reduced certifícate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certificate in a single pass. Based on this notion, we show how to instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker

ELT professors’ perceptions towards their e-teaching performance in times of global crisis: a comparative study

"This study aims to explore and compare ELT professors’ perceptions from two Higher Education institutions about the challenges and strategies they have encountered regarding their digital performance experience during the pandemic lockdown. This research intends to find out similarities and discrepancies between these Higher Educations Institutions in central Mexico. A qualitative method approach was used to analyze the data to identify the challenges and strategies that were used by the professors during the pandemic lockdown. The results from this study could contribute to a better comprehension of how professors embraced uncertainty to accomplish their teaching practice in times of contingency and raise awareness through personal insights of language teachers concerning their competence in using technical materials and attitudes toward the use of digital technology to achieve their learning objectives in online language instruction"

A characterization of non-archimedeanly quasimetrizable spaces

In this paper we introduce a new structure on topological spaces which allows us to give a characterization of non-archimedeanly quasipseudometrizable spaces

History of personal development of teachers in the province of Granada in the rural context. Study of cases

Una ventana con vistas a la escuela rural. Este artículo trata de plasmar la realidad de la educación en el contexto rural, de las personas que trabajan en esta escuela y qué experiencias personales y profesionales les han llevado a impartir docencia en ellas. En base a la problemática y dificultades relacionadas con la escuela rural y el profesorado que en ella trabaja, se realiza un estudio de casos cuya finalidad es conocer, en la medida de lo posible, qué aspectos de la vida de estos tres sujetos son los que más les han influido y condicionado para desempeñar su labor docente en el contexto rural. Para dicho trabajo, se utiliza la técnica de historia de vida y desarrollo personal para la cual se han seguido los siguientes pasos: elaboración de un protocolo de entrevistas, transcripción de las entrevistas, análisis cualitativo de las respuestas mediante el diseño de un sistema de categorías y, por último, un inventario de valores. Mediante las entrevistas y su análisis, se conoce, también, la visión que estos docentes tienen acerca del lugar en que desempeñan su práctica educativa. Todo el material utilizado ha sido elaborado teniendo en cuenta el protocolo diseñado por Atkinson (1997), llevando a cabo las adaptaciones oportunas para la información que se pretende recoger y analizar. Así como, el protocolo de entrevistas fue revisado exhaustivamente por tres profesionales de la materia.A window overlooking the rural school. This article tries to capture the reality of education in the rural context, of the people who work in this school and what personal an professional experiences have led them to teach there. Based on the problems and difficulties related to the rural school and the teachers who work in it, a case study is carried out whose purpose is to know, as far as possible, what aspects of the lives of these three subjects are those that more they have influenced and conditioned them to carry out their teaching work in the rural context. For this work, the life history and personal development technique is used, for which the following steps have been followed: preparation of an interview protocol, transcription of the interviews, qualitative analysis of the responses through the design of category system and finally, an inventory of values. Through the interviews and their analysis, it is also known the vision that these teachers have about the place in which they carry out their educational practice. All the material used has been prepared taking into account the protocol designed by Atkinson (1997), carrying out the appropriate adaptations for the information to be collected and analysed. Likewise, the interview protocol was exhaustively reviewed by three professionals in the field

Dimension, inverse limits and GF-spaces

In this paper we characterize (covering) dimension in metrizable spaces in terms of fractal structures. We will also study dimension for compact metric spaces, giving a theorem relating dimension and a certain class of inverse limits, similar to that of Freudenthal

Desarrollo de una aplicación móvil para el tratamiento de las enfermedades cardiovasculares

El uso de aplicaciones en dispositivos móviles ha ido creciendo con el paso de los años, siendo hoy en día una herramienta fundamental en un amplio ámbito que va desde profesionales de las comunicaciones, economía, comercio y salud hasta las destinadas al ocio, viajes, deportes... Este proyecto presenta una aplicación para Android que está enfocada al ámbito de la medicina y su objetivo específico es proporcionar una solución a uno de los problemas actuales que existe en el Hospital Virgen de la Salud de Toledo. Este dilema se refiere a la necesidad de agilizar el tratamiento de datos en los factores relativos al riesgo cardiovascular mediante el empleo de herramientas tecnológicas de última generación. Para lograr esta meta hemos diseñado una interfaz intuitiva y simple, proporcionando agilidad al médico en el cálculo del riesgo cardiovascular y asistencia complementaria a los métodos convencionales. La aplicación está enfocada para ser gestionada por los médicos, permitiéndoles almacenar datos identificativos de un paciente y tratar la información concerniente a su estado en lo que respecta a la hipertensión arterial, el colesterol, la diabetes, el tabaquismo y el índice de masa corporal. Esta última característica será tomada como base por la app para la determinación del riesgo cardiovascular del paciente y la redacción de una breve sinopsis descriptiva que ayude al profesional sanitario en la prescripción de un tratamiento personalizado

Maximum-Likelihood Phylogenetic Inference with Selection on Protein Folding Stability.

Despite intense work, incorporating constraints on protein native structures into the mathematical models of molecular evolution remains difficult, because most models and programs assume that protein sites evolve independently, whereas protein stability is maintained by interactions between sites. Here, we address this problem by developing a new meanfield substitution model that generates independent site-specific amino acid distributions with constraints on the stability of the native state against both unfolding and misfolding. The model depends on a background distribution of amino acids and one selection parameter that we fix maximizing the likelihood of the observed protein sequence. The analytic solution of the model shows that the main determinant of the site-specific distributions is the number of native contacts of the site and that themost variable sites are those with an intermediate number of native contacts. The meanfield models obtained, taking into account misfolded conformations, yield larger likelihood than models that only consider the native state, because their average hydrophobicity is more realistic, and they produce on the average stable sequences for most proteins. We evaluated the mean-field model with respect to empirical substitution models on 12 test data sets of different protein families. In all cases, the observed site-specific sequence profiles presented smaller Kullback–Leibler divergence from the mean-field distributions than from the empirical substitution model. Next, we obtained substitution rates combining the mean-field frequencies with an empirical substitution model. The resulting mean-field substitutionmodel assigns larger likelihood than the empiricalmodel to all studied families when we consider sequences with identity larger than 0.35, plausibly a condition that enforces conservation of the native structure across the family. We found that the mean-field model performs better than other structurally constrained models with similar or higher complexity. With respect to the much more complex model recently developed by Bordner and Mittelmann, which takes into account pairwise terms in the amino acid distributions and also optimizes the exchangeability matrix, our model performed worse for data with small sequence divergence but better for data with larger sequence divergence. The mean-field model has been implemented into the computer program Prot_Evol that is freely available at ttp://ub.cbm.uam.es/software/Prot_Evol.phpMinistery of Economy through the grant BFU-40020 to U.B. M.A. was supported by the Spanish Government through the Juan de la Cierva fellowship JCI-2011-10452. Research at the CBMSO is facilitated by the Fundación Ramón ArecesPeer Reviewe