Numerical analysis of the vibrational behavior of the moving assembly of a dynamic loudspeaker

En este trabajo se describe el proceso llevado a cabo para analizar numéricamente mediante el método de los elementos finitos (MEF) el comportamiento vibratorio del conjunto móvil de un altavoz dinámico de bobina con doble suspensión inferior y en ausencia de la superior. El estudio se centra en el rango de baja frecuencia. El calibrado del modelo se realiza en base a medidas experimentales de la frecuencia de resonancia y desplazamiento del diafragma. Se hace énfasis en la importancia de los factores de participación asociados a la fuerza de excitación y en los cambios que se producen en estos al introducir fuerzas no equilibradas. Así mismo, el análisis proporciona datos para decidir sobre la distancia entre suspensiones, su número óptimo de pliegues y la ubicación de las trencillas, siendo estos parámetros de gran interés en el diseño de este tipo de altavoces.This paper describes the process undertaken to analyze numerically the vibrational behavior of the moving assembly of a dynamic loudspeaker with double bottom suspension and in the absence of the above one using the finite element method (FEM). The study focuses on the low frequency range. Model calibration was performed based on experimental measurements of the resonance frequency and diaphragm displacement. The importance of the participation factors associated to the excitation force and the changes produced in these when unbalanced forces are introduced are emphasized. The analysis also provides data to decide on the distance between suspensions, their optimal number of folds and the placement of the lead wires, parameters of great interest on the design of this type of loudspeakers.Peer Reviewe

Introduction: responsibility for action and belief

This paper is a presentation of a special issue of Philosophical Explorations, whose origin is a meeting held in Valencia in 2008. The issue includes contributions by David Widerker, Derk Pereboom, Timothy O'Connor, Thomas Pink, Dana Nelkin, Helen Steward, Maria Alvarez, Christopher Hookway, and Pascal Engel. The paper contains a map of the main positions in the debate about free action, free will, and moral responsibility, as well as a reference to some central issues in this traditional and yet lively debate. The discussion about responsibility and related notions, such as agency and freedom, has recently been extended from decisions and actions to beliefs, to give rise to new research perspectives, both in epistemology and in the metaphysics of freedom and responsibility for actions. The papers included in this special issue are valuable contributions to the research about freedom and responsibility in both action and belief

Chapter 5. Overcoming scepticism? Belief and moral responsibility

Este es el capítulo 5 de mi libro Moral Responsibility: the ways of scepticism (Routledge 2006). Los cuatro primeros capítulos son comentarios extensos a un importante argumento escéptico sobre la posibilidad de la responsabilidad moral, que puede reconstruirse o extraerse fácilmente a partir de la bibliografía actual sobre la responsabilidad moral. El argumento, que denomino SMR (por “Scepticism about Moral Responsibility”), puede formularse como sigue: Primera premisa (A): O el determinismo es verdadero o no lo es. Segunda premisa (B): Si el determinismo es verdadero, la responsabilidad moral no es posible. Tercera premisa (C): Si el determinismo no es verdadero, la responsabilidad moral no es posible. Conclusión (D): Por lo tanto, la responsabilidad moral no es posible. Este argumento es lógicamente válido, de modo que, si, como es mi caso, queremos negar la conclusión y defender la posibilidad de la responsabilidad moral, hemos de negar alguna de las premisas. El capítulo 5 es un intento de rechazar la conclusión escéptica del argumento SMR mediante la negación de la premisa C. Esta premisa descansa sobre todo en la tesis según la cual el indeterminismo hace de nuestras y acciones episodios arbitrarios o azarosos, privándonos así del control (y en especial del control racional) que sería necesario para ser moralmente responsables de ellas. El capítulo 5 trata de mostrar que esta tesis es falsa, de modo que la indeterminación causal de nuestras decisiones y acciones permite y es compatible con nuestro control racional, e incluso con nuestro control profundo o último, sobre ellas. Para ello defiendo, en lugar de una aproximación volitiva a la responsabilidad moral, basada en elecciones y actos de voluntad, una aproximación cognitiva, basada en la importancia de nuestras creencias evaluativas.BFF2003-08335-C03-01This is chapter 5 of my book Moral Responsibility: the ways of scepticism (Routledge 2006). The first four chapters are extensive commentaries on an important skeptical argument about the possibility of moral responsibility, which can be easily reconstructed or extracted from the current literature on moral responsibility. The argument, which I call SMR (for "Scepticism about Moral Responsibility"), can be formulated as follows: First premise (A): Either determinism is true, or it is not. Second premise (B): If determinism is true, moral responsibility is not possible. Third premise (C): If determinism is not true, moral responsibility is not possible. Conclusion (D): Therefore, moral responsibility is not possible. This argument is logically valid, so if, as is my case, we want to deny the conclusion and defend the possibility of moral responsibility, we must deny at least one of its premises. Chapter 5 is an attempt to reject the skeptical conclusion of the SMR argument by rejecting premise C. This premise rests above all on the thesis according to which indeterminism makes our actions into arbitrary or random episodes, thus depriving us of the control (and especially of the rational control) that would be necessary to be morally responsible for them. Chapter 5 tries to show that this thesis is false, so that the causal indeterminacy of our decisions and actions allows, and is compatible with, our rational control, and even our deep or ultimate control, over them. To this end, I advocate, instead of a volitional approach to moral responsibility, based on choices and acts of will, a cognitive approach to it, based on the importance of our evaluative beliefs

Responsabilidad moral, causación y posibilidades alternativas

En el debate sobre la responsabilidad moral encontramos diversas aproximaciones teóricas, que frecuentemente forman dicotomías. En este artículo nos ocupamos de la que se da entre las teorías de la secuencia real, según las cuales la responsabilidad moral se funda únicamente en la secuencia real que conduce a la acción, y las teorías de las posibilidades alternativas, que subrayan la importancia de las secuencias y posibilidades alternativas al alcance del agente. Me ocupo especialmente de una versión reciente del primer tipo de teorías, sostenida por Carolina Sartorio, según la cual los únicos aspectos de la secuencia real que son relevantes para la responsabilidad moral son los aspectos causales. En este artículo sostengo que ambos tipos de teorías no son excluyentes, sino compatibles y complementarias. Esta complementariedad permite mantener intuiciones importantes sobre la responsabilidad moral. In the debate on moral responsibility, we find various theoretical approaches, which often form dichotomies. In this article we deal with the dichotomy between theories of the actual sequence, according to which moral responsibility is grounded solely on the actual sequence that leads to action, and theories of alternative possibilities, which underline the importance of alternative sequences and possibilities available to the agent. I deal particularly with a recent version of the first type of theories, developed by Carolina Sartorio, according to which the only aspects of the actual sequence that are relevant to moral responsibility are causal aspects. In this article I argue that both types of theories are not mutually exclusive, but compatible and complementary. This complementarity makes it possible to maintain important intuitions about moral responsibility

Análisis tiempo-frecuencia de mapas de activación cardíaca en fibrilación ventricular

El análisis de mapas de activación permite investigar la estructura de la fibrilación ventricular cardíaca (FV). El presente trabajo plantea una revisión de la utilización de objetos de interés (blobs), usados en procesado de imágenes y aplicados también a mapas de activación cerebral y cardíaca, mediante su generación a partir de representaciones tiempo-frecuencia de registros FV. Su estudio proporciona información sobre qué frecuencias de la señal están presentes en un instante dado, así como su distribución espacial. También permiten determinar el momento en que una determinada frecuencia aparece y desaparece de cada electrodo, por lo que constituye una herramienta interesante para analizar los mecanismos de generación y mantenimiento de la FV

Mobility assessment in people with Alzheimer disease using smartphone sensors

[EN] Background Understanding the functional status of people with Alzheimer Disease (AD), both in a single (ST) and cognitive dual task (DT) activities is essential for identifying signs of early-stage neurodegeneration. This study aims to compare the performance quality of several tasks using sensors embedded in an Android device, among people at different stages of Alzheimer and people without dementia. The secondary aim is to analyze the effect of cognitive task performance on mobility tasks. Methods This is a cross-sectional study including 22 participants in the control group (CG), 18 in the group with mild AD and 22 in the group with moderate AD. They performed two mobility tests, under ST and DT conditions, which were registered using an Android device. Postural control was measured by medial-lateral and anterior-posterior displacements of the COM (MLDisp and APDisp, respectively) and gait, with the vertical and medial-lateral range of the COM (Vrange and MLrange). Further, the sit-to-stand (PStand) and turning and sit power (PTurnSit), the total time required to complete the test and the reaction time were measured. Results There were no differences between the two AD stages either for ST or DT in any of the variables (p > 0.05). Nevertheless, people at both stages showed significantly lower values of PStand and PTurnSit and larger Total time and Reaction time compared to CG (p < 0.05). Further, Vrange is also lower in CDR1G than in CG (p < 0.05). The DT had a significant deleterious effect on MLDisp in all groups (p < 0.05) and on APDisp only in moderate AD for DT. Conclusions Our findings indicate that AD patients present impairments in some key functional abilities, such as gait, turning and sitting, sit to stand, and reaction time, both in mild and moderate AD. 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Realtime calibration of the A4 electromagnetic lead fluoride calorimeter

Sufficient energy resolution is the key issue for the calorimetry in particle and nuclear physics. The calorimeter of the A4 parity violation experiment at MAMI is a segmented calorimeter where the energy of an event is determined by summing the signals of neighbouring channels. In this case the precise matching of the individual modules is crucial to obtain a good energy resolution. We have developped a calibration procedure for our total absorbing electromagnetic calorimeter which consists of 1022 lead fluoride (PbF_2) crystals. This procedure reconstructs the the single-module contributions to the events by solving a linear system of equations, involving the inversion of a 1022 x 1022-matrix. The system has shown its functionality at beam energies between 300 and 1500 MeV and represents a new and fast method to keep the calorimeter permanently in a well-calibrated state