An artifact in fits to conic-based surfaces

It is common in Physiological Optics to fit the corneal and the lens surfaces to conic-based surfaces (usually ellipse-based surfaces), obtaining their characteristic radius of curvature and asphericity. Here we show that the variation in radius and asphericity due to experimental noise is strongly correlated. This correlation is seen both in experimental data of the corneal topographer Pentacam and in simulations. We also show that the effect is a characteristic of the geometry of ellipses, and not restricted to any experimental device or fitting procedure.Comment: 5 pages, 5 figure

Un análisis del tratamiento de la semejanza en los documentos oficiales y textos escolares de matemáticas en la segunda mitad del siglo XX

Este trabajo centra su atención en el tratamiento de la semejanza y el teorema de Thales en los documentos curriculares oficiales y en los libros de texto de matemáticas correspondientes a las edades de 11-16 años durante los últimos cincuenta años. La distinción de tres momentos en la evolución histórica de la semejanza ha permitido identifi car tres aproximaciones al concepto cuando se considera como objeto de enseñanza. Estas aproximaciones y la forma de establecer las relaciones entre semejanza y teorema de Thales son los elementos que utilizamos en el análisis. En el estudio se pone de manifiesto la cantidad de restricciones que pesan en la enseñanza de dichos conceptos y su desplazamiento a voluntad de los cambios de planes.This work focuses on the development of similarity and Thales Theorem in the curriculum documents and mathematics textbooks belonging to 11-16 year olds level, during the last fifty years. The differentiation of the three moments in the historic development of similarity allows to identify three approaches to the concept when it is considered a teaching object. These different approaches and the way of establishing the relation between similarity and Thales Theorem are the aspects that I use in the analysis. The results show the great amount of restrictions that have infl uenced the teaching of the concepts and the different role that they play in the distinct periods considered

La formación geométrica en la formación inicial de profesores de Enseñanza Primaria a través de entornos de aprendizaje

El objetivo de este proyecto es la identificación de aspectos de un contenido matemático que nuestros alumnos (estudiantes para profesores de primaria) sean capaces de trasladar desde la información teórica suministrada a la realización de la tarea propuesta. Dicha tarea forma parte de un entorno de aprendizaje. Con los datos obtenidos desde el trabajo de los estudiantes pretendemos validar los diseños y analizar los resultados para modificar, si procede, dichos entornos de aprendizaje, ampliarlos o rediseñarlos, contribuyendo a los esfuerzos por integrar las informaciones procedentes de las investigaciones teóricas con la práctica en los programas de formación inicial

«More human than human»: Instrumentalization and uprising of artificial subjects

La vida sintética, orgánica y mixta creada artificialmente tiene siempre como fin satisfacer algún tipo de necesidad de su creador, el ser humano. La inteligencia de estos engendros, así como su interacción con el medio, puede ser muy variable proporcionándoles distintos grados de conciencia. Desde los robots de limpieza hasta los clones, pasando por cíborgs y replicantes o por superordenadores que toman el mando, el inventario de sujetos artificiales autoconscientes en el cine de ciencia ficción es prácticamente inagotable. En el presente artículo abordaremos algunas de sus representaciones más icónicas e influyentes para el género, así como el impacto que estas han tenido sobre nuestra concepción de la propia naturaleza humanaArtificially created life, whether it is synthetic, organic or mixed, always has the purpose of fulfilling some need of its creator, human kind. The intelligence of these beings as well as their interaction with the environment can vary widely, providing them with different degrees of consciousness. From maintenance robots to clones, through cyborgs and replicants or supercomputers that take control, the inventory of self-conscious artificial subjects in science fiction is almost endless. In this article we will take a look at some of the most iconic and influential manifestations of artificial identities in Sci Fi and see how they have moulded our perception of human nature itsel

A bibliometric analysis of doctoral dissertations in the subdiscipline of audiovisual translation

This work analyses the evolution and current state of the art in audiovisual translation research as portrayed in doctoral dissertations worldwide, which is part of the studies I am conducting for my own PhD thesis at the University of Alicante, Spain. Audiovisual translation studies is still a very young subdiscipline of translation studies, and more research in this field is needed to describe and explain what its authors, institutions, journals, research groups and other actors have done so far, how and why. In this connection, doctoral dissertations usually represent the most comprehensive, cutting-edge investigation projects that researchers face in their careers, and therefore their study brings about abundant information enabling us to provide a portrait of the subdiscipline. That information includes main topics and trends, academic networks of authors, gender differences between authors and supervisors, academic networks, most productive supervisors, universities and countries, most common languages, years of publication or access mode. All this data helps to analyse, delineate and categorise the subdiscipline of audiovisual translation

Bandpass filters for space applications with wide spurious-free range

Design of microwave llters is an important activity, due to the fact that microwave are an integral part of a lot of communications systems; specially in spatial commu- nications systems or terrestrial mobile systems. In the microwave eld, waveguide technology still has a very large acceptance, above all in high power applications, and the cases in which the losses reduction is an important factor that has to be taken into account. In this project, it will be reviewed waveguide technology for bandpass lters design and new techniques which try to increase the spurious-free range will be investi- gated. Concretely, a new concept will be explored in order to remove such spurious band. This technique is based on the control of the coupling windows widht. In addition, it has been worked in the design of a bandpass lter for an antenna phase array that work at S-band. This lter has been designed in SIW (Substrate Inte- grated Waveguide) technology. Finally, it has been studied the use of this waveguide loaded with Ring Resonators and Complementary Split Ring Resonator (CSRR) for the realization of bandpass ters with size reduction.Escuela Técnica Superior de Ingeniería de TelecomunicaciónUniversidad Politécnica de Cartagen

Using real-time information to reschedule jobs in a flowshop with variable processing times

Versión revisada. Embargo 36 mesesIn a time where detailed, instantaneous and accurate information on shop-floor status is becoming available in many manufacturing companies due to Information Technologies initiatives such as Smart Factory or Industry 4.0, a question arises regarding when and how this data can be used to improve scheduling decisions. While it is acknowledged that a continuous rescheduling based on the updated information may be beneficial as it serves to adapt the schedule to unplanned events, this rather general intuition has not been supported by a thorough experimentation, particularly for multi-stage manufacturing systems where such continuous rescheduling may introduce a high degree of nervousness in the system and deteriorates its performance. In order to study this research problem, in this paper we investigate how real-time information on the completion times of the jobs in a flowshop with variable processing times can be used to reschedule the jobs. In an exhaustive computational experience, we show that rescheduling policies pay off as long as the variability of the processing times is not very high, and only if the initially generated schedule is of good quality. Furthermore, we propose several rescheduling policies to improve the performance of continuous rescheduling while greatly reducing the frequency of rescheduling. One of these policies, based on the concept of critical path of a flowshop, outperforms the rest of policies for a wide range of scenarios.Ministerio de Ciencia e Innovación DPI2016-80750-

Efficiency of the solution representations for the hybrid flow shop scheduling problem with makespan objective

In this paper we address the classical hybrid flow shop scheduling problem with makespan objective. As this problem is known to be NP-hard and a very common layout in real-life manufacturing scenarios, many studies have been proposed in the literature to solve it. These contributions use different solution representations of the feasible schedules, each one with its own advantages and disadvantages. Some of them do not guarantee that all feasible semiactive schedules are represented in the space of solutions –thus limiting in principle their effectiveness– but, on the other hand, these simpler solution representations possess clear advantages in terms of having consistent neighbourhoods with well-defined neighbourhood moves. Therefore, there is a trade-off between the solution space reduction and the ability to conduct an efficient search in this reduced solution space. This trade-off is determined by two aspects, i.e. the extent of the solution space reduction, and the quality of the schedules left aside by this solution space reduction. In this paper, we analyse the efficiency of the different solution representations employed in the literature for the problem. More specifically, we first establish the size of the space of semiactive schedules achieved by the different solution representations and, secondly, we address the issue of the quality of the schedules that can be achieved by these representations using the optimal solutions given by several MILP models and complete enumeration. The results obtained may contribute to design more efficient algorithms for the hybrid flow shop scheduling problem.Ministerio de Ciencia e Innovación DPI2016-80750-