623 research outputs found

    Daylight Spectrum Index: A New Metric to Assess the Affinity of Light Sources with Daylighting

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    The current scenario of colorimetry shows a wide variety of different metrics which do not converge in the assessment of the color rendering of light sources. The limitations of the Color Rendering Index have promoted the emergence of new metrics, such as the Color Quality Scale. As in the case of the previous metric, these new concepts are based on the analysis of the deviation of different color samples in a color space, contrasting the results with those obtained with a light source reference, which can vary depending on the color temperature. Within this context, the Daylight Spectrum Index is proposed. This new concept aims to determine the affinity with daylighting of electric light sources, comparing the resulting spectral power distributions of the lamps studied and that observed under natural light. The affinity of an electric light source with daylighting allows for lower energy consumption due to the better performance of human vision. The new metric proposed is evaluated following the results obtained from 80 surveys, demonstrating the usefulness of this new concept in the quantification of color rendering of LED lamps and the affinity of electric light sources with daylighting.Government of Spain BIA2017-86997-

    Universal Cycles for Some Combinatorial Objects

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    A de Bruijn cycle commonly referred to as a universal cycle (u-cycle), is a complete and compact listing of a collection of combinatorial objects. In this paper, we show the power of de Bruijn\u27s original theorem, namely that the cycles bearing his name exist for n-letter words on a k-letter alphabet for all values of k,n, to prove that we can create de Bruijn cycles for multi-sets using natural encodings and M-Lipschitz n-letter words and the assignment of elements of [n]={1,2,...,n} to the sets in any labeled subposet of the Boolean lattice; de Bruijn\u27s theorem corresponds to the case when the subposet in question consists of a single ground element. In this paper, we also show that de Bruijn\u27s cycles exist for words with weight between s and t, where these parameters are suitably restricted

    Sincronización de caos mediante observadores para cifrado en comunicaciones

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    En este trabajo, se presenta una estrategia de sincronización para la clase más simple de sistemas caóticos, conocida como clase P. El problema de sincronización es tratado mediante la aplicación de la teoría de observadores de estado para reconstruir las señales. Además, se presenta un estudio donde la estrategia de sincronización propuesta es aplicada al problema de cifrado de información en un sistema de comunicaciones seguras. Se presentan resultados en simulación, donde se ilustra el desempeño de este esquema y su potencial en aplicaciones de comunicación segur

    Influence of the notch-sharpening technique on styrene-acrylonitrile fracture behavior

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    The Centre Catala del Plastic and Universidad Rey Juan Carlos laboratories joined forces to investigate the effect of the notch-sharpening technique on the fracture parameters of styrene-acrylonitrile. Contact notch-sharpening techniques, such as razor tapping, razor sliding, and razor broaching, and a noncontact procedure, femtolaser, were analyzed. The fracture values of the samples with notches sharpened via contact techniques were divided into two groups: one with pop-in and the other with no pop-in in the load-displacement records; this resulted in the lowest and highest fracture toughnesses, respectively. The fracture parameters of the specimens with notches sharpened via a femtolaser were between those of the samples with notches sharpened via contact procedures in which pop-in occurred and those in which it did not. To explain these results, the crack front of the nontested specimens after sharpening was investigated in depth, we identified the type of damage and measured its size and the crack tip radii. The morphology of the crack front was related to the fractographic study.Postprint (author's final draft

    Control de sistemas caóticos

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    Se presenta una estrategia para control de caos (supresión y sincronización) en una clase de sistemas. Los sistemas estudiados, conocidos como clase P, son los más simples que exhiben caos. Se diseña un observador adaptable para una clase de sistemas afines en el estado, el cual se sincroniza con los sistemas clase P al estimar sus estados y parámetros desconocidos. Además, se considera una ley de control, dependiente de las estimaciones del observador, que permite realizar supresión en la clase de sistemas estudiada. Se presentan resultados mediante simulaciones y pruebas experimentales para ilustrar el desempeño de dichos esquemas. Finalmente se exponen algunas conclusiones

    Self-regulation in family foster children

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    This poster presents research on foster children’s capacities for self-regulation and its relation to adversity history. Children in family foster care are a vulnerable population due to their experiences of maltreatment and separation from primary caregivers. Research has shown high rates of behavioral problems and impulsivity in these children, as well as other difficulties such as poor academic adjustment. Recent theory and research advances suggest some of these problems are due to deficits in self-regulatory capacities, such as executive functions or emotion regulation. Early adversity in key developmental stages, like that suffered by many foster children, can undermine the normative development of these capacities and, consequently, their psychosocial adjustment. This study explores this topic in a sample of foster children between 4 and 8 years old who were living in non-relative foster families for at least six months in Southern Spain. We used the Behavior Rating Inventory of Executive Function (BRIEF; Gioia, Isquith, Guy, & Kenworthy, 2000), a widely used parent-reported questionnaire, to assess self-regulation in the foster children. The BRIEF was answered by the primary foster caregiver during a home visit. The information regarding adverse events and trajectory in the child protection services was obtained through case records in collaboration with caseworkers. The results of this study show us information about the capacities of self-regulation of children in family foster care. Due to the centrality of self-regulation in development and the fact that it remains responsive to well-designed interventions beyond early childhood, interventions for foster children and families should consider targeting this dimension to improve their outcomes

    Optimization of connections for spatial modular structures

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    Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.Every year Seville’s city Council orders the construction of a giant gateway for the celebration of the April Fair. These constructions, whose dimensions are approximately 50 meters length, 40 meters height and variable depth of 4 to 5 meters, are spatial modular structures composed of steel tubular elements connected by clamps and covered by wood boards. The consideration or not of the eccentricities introduced by the connection element as well as the determination of the stiffness to consider is one of the major problems when developing the analysis model. The construction company aims to achieve their optimization in order to reduce the final cost. This paper investigates about how different ways of modeling these connections affects the optimization of the final model. The extent to which the modification of the position of the eccentricities influences the optimization is also discussed, as this aspect is difficult to control on site

    On delay-dependent robust stability under model transformation of some neutral systems

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    summary:This paper focuses on the delay-dependent robust stability of linear neutral delay systems. The systems under consideration are described by functional differential equations, with norm bounded time varying nonlinear uncertainties in the "state" and norm bounded time varying quasi-linear uncertainties in the delayed "state" and in the difference operator. The stability analysis is performed via the Lyapunov-Krasovskii functional approach. Sufficient delay dependent conditions for robust stability are given in terms of the existence of positive definite solutions of LMIs

    Practical Experiences in Web Engineering

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    Web Engineering is defined like a new area to propose models, techniques, processes, architectures, etc. in order to deal correctly with the special characteristics of the web environment. In the last years, new methodological approaches appeared in this environment. However, Web Engineering is not often applied in industries and real pro jects. This paper presents a general vision of a web approach, named NDT (Navigational Development Techniques) and it is focused on the study of its practical applications
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