Mechatronics of a ball screw drive using a N degrees of freedom dynamic model

High performance position control in machine tools can only be achieved modelling the dynamic behavior of the mechatronic system composed by the motor, transmission and control during the design stage. In this work, a complex analytical model of a ball screw drive is presented and integrated in a mechatronic model of the actuator to predict the dynamic behaviour and analyze the impact of each component of the transmission. First, a simple 2 degrees of freedom model is presented, and is analysis sets the basis for the development of a more complex model of several degrees of freedom, whose resulting fundamental transfer functions are represented using natural and modal coordinates. The modeling in modal coordinates carries a reduction of the transfer function that reduces computational work. The two models are compared and experimentally validated in time and frequency domain by means of experimental tests carried out on a specifically developed ball screw drive test benchMinisterio de Economía y Competitividad: Project DPI2015-64450-R (MINECO/FEDER, UE) University of the Basque Country (UPV/EHU) under the program UFI 11/29 Departamento de Educación, Política Lingüística y Cultura” of the regional government of the Basque Country (IT949-16

Malware distributions and graph structure of the Web

Knowledge about the graph structure of the Web is important for understanding this complex socio-technical system and for devising proper policies supporting its future development. Knowledge about the differences between clean and malicious parts of the Web is important for understanding potential treats to its users and for devising protection mechanisms. In this study, we conduct data science methods on a large crawl of surface and deep Web pages with the aim to increase such knowledge. To accomplish this, we answer the following questions. Which theoretical distributions explain important local characteristics and network properties of websites? How are these characteristics and properties different between clean and malicious (malware-affected) websites? What is the prediction power of local characteristics and network properties to classify malware websites? To the best of our knowledge, this is the first large-scale study describing the differences in global properties between malicious and clean parts of the Web. In other words, our work is building on and bridging the gap between \textit{Web science} that tackles large-scale graph representations and \textit{Web cyber security} that is concerned with malicious activities on the Web. The results presented herein can also help antivirus vendors in devising approaches to improve their detection algorithms

Theory of frequency and phase synchronization in a rocked bistable stochastic system

We investigate the role of noise in the phenomenon of stochastic synchronization of switching events in a rocked, overdamped bistable potential driven by white Gaussian noise, the archetype description of Stochastic Resonance. We present a new approach to the stochastic counting process of noise-induced switching events: starting from the Markovian dynamics of the nonstationary, continuous particle dynamics one finds upon contraction onto two states a non-Markovian renewal dynamics. The output frequency is determined as the velocity of the underlying discrete phase dynamics. The phenomenon of noise-assisted phase synchronization is investigated in terms of an effective, instantaneous phase diffusion. The theory is applied to rectangular-shaped rocking signals versus increasing input-noise strengths. Precise numerical simulations corroborate very favorably our analytical results. The novel theoretical findings are also compared with prior findings.Comment: 14 pages, 4 figure

Arithmetic Properties of Integers in Chains and Reflections of g-ary Expansions

During the preparation of this paper, the first author was partially supported by project MTM2014-55421-P from the Ministerio de Economia y Competitividad and the second author was partially supported by Australian Research Council Grant DP140100118

Higher education for samrt specialisation. The case of Navarre, Spain

This report gathers the main findings extracted from the Navarre case study carried out in the framework of the Higher Education and Smart Specialisation (HESS) project managed by the Joint Research Centre of the European Commission. Navarre has been one of the two regions covered as case studies during the first phase of the project. The overall aim of HESS is to understand and provide support to national and regional authorities on how to integrate higher education into the policy mixes of their Smart Specialisation Strategies (S3). This technical report provides some interesting insights into how an advanced region with high involvement of universities in the early phase of S3 definition is facing the challenges of their role in the implementation phase. On the one hand, it shows that different universities in the same region are likely to vary in nature and function and as such may contribute differently to the S3. In Navarre, one of the two universities is more research oriented with a strong focus on the attraction of international talent, while the other is more regionally rooted with close ties to local companies and stakeholders. On the other hand, the report identifies tensions in engaging individual researchers in regional development activities, as well as potential mechanisms and tools to overcome them. The methodology used during the project has included qualitative research methods, participatory workshops and desk-research activitiesEste informe recoge las principales conclusiones extraídas del estudio de caso de Navarra realizado en el marco del proyecto Higher Education and Smart Specialisation (HESS) gestionado por el Centro Común de Investigación de la Comisión Europea. Navarra ha sido una de las dos regiones cubiertas como casos de estudio durante la primera fase del proyecto. El objetivo general de HESS es comprender y proporcionar apoyo a las autoridades nacionales y regionales sobre cómo integrar la educación superior en las combinaciones de políticas de sus Estrategias de Especialización Inteligente (S3). Este informe técnico proporciona algunas ideas interesantes sobre cómo una región avanzada con una alta participación de las universidades en la fase inicial de la definición de la S3 está enfrentando los desafíos de su papel en la fase de implementación. Por un lado, muestra que las diferentes universidades de la misma región pueden variar en su naturaleza y función y, como tal, pueden contribuir de manera diferente a la S3. En Navarra, una de las dos universidades está más orientada a la investigación con un fuerte enfoque en la atracción de talento internacional, mientras que la otra está más enraizada regionalmente con estrechos lazos con las empresas y actores locales. Por otra parte, el informe identifica las tensiones en la participación de los investigadores individuales en actividades de desarrollo regional, así como los posibles mecanismos y herramientas para superarlas. La metodología utilizada durante el proyecto ha incluido métodos de investigación cualitativa, talleres participativos y actividades de investigación de escritorio

Algebraic entropy, automorphisms and sparsity of algebraic dynamical systems and pseudorandom number generators

ABSTRACT: We present several general results that show how algebraic dynamical systems with a slow degree growth and also rational automorphisms can be used to construct stronger pseu-dorandom number generators. We then give several concrete constructions that illustrate the applicability of these general results

On irreducible divisors of iterated polynomials

D. Gómez-Pérez, A. Ostafe, A.P. Nicolás and D. Sadornil have recently shown that for almost all polynomials f?Fq[X]f?Fq[X] over the finite field of qq elements, where qq is an odd prime power, their iterates eventually become reducible polynomials over FqFq. Here we combine their method with some new ideas to derive finer results about the arithmetic structure of iterates of ff. In particular, we prove that the nnth iterate of ff has a square-free divisor of degree of order at least n1+o(1)n1+o(1) as n?8n?8 (uniformly in qq)

Impact of Initial Soil Temperature Derived from Remote Sensing and Numerical Weather Prediction Datasets on the Simulation of Extreme Heat Events

Extreme heat weather events have received increasing attention and has become of special importance as they can remarkably affect sectors as diverse as public health, energy consumption, water resources, natural biodiversity and agricultural production. In this regard, summer temperatures have become a parameter of essential interest under a framework of a hypothetical increase in the number of intense-heat conditions. Thus, their forecast is a crucial aspect bearing in mind a mitigation of the effects and impacts that these intense-heat situations could produce. The current work tries to reach a better understanding of these sorts of situations that are really common over the Western Mediterranean coast. An extreme heat episode that took place in the Valencia Region in July 2009 is analysed, based on the simulations performed with the Regional Atmospheric Modeling System (RAMS). This event recorded maximum temperatures exceeding 40 °C amply extended over the region besides reaching minimum temperatures up to 25.92 °C. We examine the role of improved skin and soil temperature (ST) initial conditions in the forecast results by means of different modelling and satellite-derived products. The influence of incorporating the Land Surface Temperature (LST) into RAMS is not found to produce a meaningful impact on the simulation results, independently of the resolution of the dataset used in the initial conditions of the model. In contrast, the introduction of the ST in lower levels, not only the skin temperature, has a more marked decisive effect in the simulation. Additionally, we have evaluated the influence of increasing the number of soil levels to spread deeper underground. This sensitivity experiment has revealed that more soil levels do not produce any meaningful impact on the simulation compared to the original one. In any case, RAMS is able to properly capture the observed patterns in those cases where a Western advection is widely extended over the area of study. This region’s variability in orography and in distances to the sea promotes the development of sea-breeze circulations, thus producing a convergence of two opposite wind flows, a Western synoptic advection and a sea-breeze circulation. As a result, the RAMS skill in those cases where a sea breeze is well developed depends on the proper location of the boundary and convergence lines of these two flows.This work has been funded by the Spanish Ministerio de Economía y Competitividad and the European Regional Development Fund (FEDER) through the project CGL2015-64268-R (MINECO/FEDER, UE), by the Regional Government of Valencia through the project PROMETEOII/2014/086 and by the Spanish Ministerio de Economía y Competitividad through the project CGL2011-30433-C02-02 (MINECO)

Aprendizaje de conceptos complejos en Oceanografía a través del diseño de aplicaciones en Matlab: Una estrategia para motivar al alumnado e introducirlo en la programación

Este trabajo pretende resolver un problema detectado en el alumnado de la asignatura Oceanografía Física del Grado en Ciencias del Mar. Dicho problema está relacionado con la dificultad del alumnado actual para sentirse motivado ante el aprendizaje de conceptos complejos en Física, Química y Matemáticas así como adquirir las competencias y capacidades asociadas a dicho concepto. Se ha escogido un concepto complejo: la obtención del flujo geostrófico en el océano. El trabajo presenta un cuestionario inicial de evaluación previa tras la explicación del concepto en una clase magistral, el posterior desarrollo de una sesión de aprendizaje utilizando simulaciones virtuales y programación en Matlab así como un cuestionario final para evaluar el grado de satisfacción así como de adquisición de conocimientos y competencias tras realizar la actividad para así poder extraer conclusiones de su actividad. Aunque los cuestionarios y la sesión no se podrán aplicar hasta el curso académico 2016-17, esperamos que mejore significativamente el aprendizaje en clase, cree un ambiente favorable entre el alumnado para utilizar las nuevas tecnologías y la programación y pueda aplicarse posteriormente a otros conceptos de esta u otras asignaturas.Universidad de Alicant