Weight-2 input sequences of 1/n convolutional codes from linear systems point of view

Convolutional codes form an important class of codes that have memory. One natural way to study these codes is by means of input state output representations. In this paper we study the minimum (Hamming) weight among codewords produced by input sequences of weight two. In this paper, we consider rate 1/n and use the linear system setting called (A,B,C,D) input-state-space representations of convolutional codes for our analysis. Previous results on this area were recently derived assuming that the matrix A, in the input-state-output representation, is nonsingular. This work completes this thread of research by treating the nontrivial case in which A is singular. Codewords generated by weight-2 inputs are relevant to determine the effective free distance of Turbo codes.The research of the second author was supported by Spanish I+D+i project PID2019-108668GB-I00 of MCIN/AEI/10.13039/501100011033

1/n Turbo codes from linear system point of view

The performance of turbo codes at the error floor region is largely determined by the effective free distance, which corresponds to the minimum Hamming weight among all codeword sequences generated by input sequences of weight two. In this paper, we study turbo codes of dimension one obtained from the concatenation of two equal codes and present an upper bound on the effective free distance of a turbo code with these parameters defined over any finite field. We do that making use of the so-called (A, B, C, D) state-space representations of convolutional codes and restrict to the case where A is invertible. A particular construction, from a linear systems point of view, of a recursive systematic convolutional code of rate 1/n so that the effective free distance of the corresponding turbo code attains this upper bound is also presented.D. Napp was partially supported by the the Universitat d’Alacant (Grant No. VIGROB-287) and Generalitat Valenciana (Grant No. AICO/2017/128). V. Herranz and C. Perea were supported by the Ministerio de Economa, Industria y Competitividad within project TIN2016-80565-R

Parallel concatenated convolutional codes from linear systems theory viewpoint

The aim of this work is to characterize two models of concatenated convolutional codes based on the theory of linear systems. The problem we consider can be viewed as the study of composite linear system from the classical control theory or as the interconnection from the behavioral system viewpoint. In this paper we provide an input–state–output representation of both models and introduce some conditions for such representations to be both controllable and observable. We also introduce a lower bound on their free distances and the column distances

Las matrices de Toeplitz en la construcción de códigos convolucionales perforados

En este trabajo presentamos la modelización de la técnica de perforación de códigos convolucionales introducida por McEliece desde el punto de vista de sistemas. Aplicando esta técnica a un (2, 1, 1)-código convolucional óptimo y teniendo en cuenta las propiedades de las matrices de Toeplitz, construimos un nuevo (3, 2, 1)-código óptimo

Free the nippleProyecto de arte público participativo

[ES] El proyecto que he llevado a cabo, se titula Free the nipple, en referencia directa a la activista y cineasta Lina Esco, quien inició un movimiento en el que cuestionaba la convención de considerar indecente la exposición de los pechos de la mujer, al contrario que la exposición del torso del hombre. Se trata de una intervención de arte público participativo, desde una perspectiva de género. La motivación surge principalmente, a raíz de la censura de los pezones femeninos en las redes sociales, y en concreto en Instagram. El objetivo principal del proyecto es crear una instalación en el espacio público que invite a los y las espectadoras a la reflexión sobre la censura del cuerpo femenino, así como a la normalización del mismo. La intervención ha sido realizada mediante la técnica de moldes de alginato positivados en escayola a partir de la participación voluntaria de más de 15 mujeres.[EN] The project that I have carried out is entitled Free the nipple, in direct reference to the activist and filmmaker Lina Esco, who started a movement in which she questioned the convention of considering indecent exposure of women's breasts, unlike exposing the man's torso. It is a participatory public art intervention, from a gender perspective. The motivation arises mainly, as a result of the censorship of the female nipples on social networks, and specifically on Instagram. The main objective of the project is to create an installation in the public space that invites the public to reflect on the censorship of the female body, as well as to normalize it. The public intervention has been carried out using the plaster-positive alginate mold technique, with the voluntary participation of more than 15 women.Herranz Ruiz, MV. (2020). Free the nippleProyecto de arte público participativo. http://hdl.handle.net/10251/149859TFG

Quick and Accurate Strategy for Calculating the Solutions of the Photovoltaic Single-Diode Model Equation

The photovoltaic (PV) single-diode model is the most widely used to characterize the behavior of a PV panel because it combines high precision with moderate difficulty. Lots of methods to obtain the model parameters use optimization techniques that require the resolution of the characteristic equation thousands of times; therefore, it is essential to calculate its solutions accurately but also in the shortest possible time. The objective of this article is to describe a new numerical strategy to solve the characteristic equation in a simple, fast and precise way. The main idea is based on a reparameterization of the Lambert equation which is closely related with the infinite power tower, and some well-known bounds of this tower will be used as seeds of numerical methods. This strategy is powerful for certain “small” values of the Lambert W function argument, but it is combined with another re-expression of the Lambert equation for the remaining “large” values. The proposed numerical strategy is so precise in very few iterations that it can be suitably transformed into an explicit formula. The results obtained have been compared with some of the best options in the literature and expexperimental results prove the power of the proposed methodolog

A comparison ofmethods for the calculation of all the key points of the PV single-diode model including a new algorithm for themaximum power point

A comparison ofmethods for the calculation of all the key points of the PV single-diode model including a new algorithm for themaximum power poin

Análisis del léxico disponible español de extranjeros que estudian los grados de educación

The article analyzes the Spanish lexical availability of foreign students who study Pre-primary or Primary Educational Degrees and they are in the first or fourth course. The objective of this study is to know (1) the evolution of their vocabulary after four years of studies and (2) to analyze the differences between both groups (first and fourth). To obtain the results, the students answered a questionnaire structured in two parts: the first one, which collects sociodemographic data of the informants and the second one, which allows us to assess the lexical availability of the informants in eighteen centers of interest, the traditional sixteen and there were added the topics New Technologies: ICTand Education. The results that we have obtained show the existence of differences between the lexicon of both groups. Therefore, the study suggests the need of reinforcement of the vocabulary of future teachers.El artículo analiza el léxico disponible de los estudiantes extranjeros de los grados de educación infantil y primaria que se encuentran en primer o cuarto curso. El objetivo es conocer (1) su evolución tras cuatro años de estudios y (2) analizar las diferencias entre ambos grupos. Para ello, los estudiantes respondieron un cuestionario estructurado en dos partes: la primera recoge los datos sociodemográficos particulares de los informantes y la segunda, permite evaluar el léxico disponible de los alumnos en dieciocho centros de interés, los dieciséis tradicionales y se añadieron las áreas asociativas de Nuevas Tecnologías: TICy Educación. Los resultados obtenidos muestran la existencia de diferencias entre el léxico de ambos grupos, primero y cuarto. Por lo tanto, el estudio sugiere la necesidad de reforzar el vocabulario de los futuros profesores

Research on children's lexical availability: applications for SFL teaching

Esta investigación presenta la aportación que la disponibilidad léxica tiene en el marco de la enseñanza de Español como Lengua Extranjera y el ámbito infantil. Para poder desarrollar esta tarea se ha realizado una revisión bibliográfica sistemática que presenta a aquellos trabajos publicados sobre léxico disponible. A partir de los resultados obtenidos se ha observado una baja incidencia de investigaciones sobre ELE con población escolar (hasta 12 años), en comparación con corpus adultos. En segundo lugar, también se han localizado, a parte de los dieciséis centros de interés tradicionales, treinta áreas complementarias o novedosas que coinciden con las clasificaciones desarrolladas por el MCER para la enseñanza de vocabulario en estudiantes de ELE. Finalmente, como principal conclusión, se destaca la alta adaptabilidad que presenta la disponibilidad léxica para la enseñanza de vocabulario de ELE hecho que la convierte en una opción especialmente apropiada para desarrollar esta tarea.This research presents the contribution that lexical availability has in the field of teaching Spanish as a Foreign Language to children. In order to develop this task, a systematic bibliographic review has been carried out to present the published works on lexical availability. From the results obtained, a low incidence of research on EFL in children's samples has been observed (up to 12 years old), compared to adult corpus. Secondly, apart from the 16 traditional centers of interest, 30 complementary or innovative areas that coincide with the classifications developed by the CEFR for teaching vocabulary to EFL students have also been found. Finally, as a main conclusion, we highlight the elevated adaptability of lexical availability for teaching vocabulary in Spanish as a foreign language, which makes it a particularly appropriate approach to develop this task