The Hessian correspondence of hypersurfaces of degree 3 and 4

Let $X$ be a hypersurface in a $n$-dimensional projective space. The Hessian map is a rational map from $X$ to the projective space of symmetric matrices that sends a point $p\in X$ to the Hessian matrix of the defining polynomial of $X$ evaluated at $p$. The Hessian correspondence is the map that sends a hypersurface to its Hessian variety; i.e. the Zariski closure of its image via the Hessian map. In this paper, we study this correspondence for the cases of hypersurfaces of degree $3$ and $4$. We prove that, for degree $3$ and $n=1$, the map is two to one, and that, for degree $3$ and $n\geq 2$, and for degree $4$, the Hessian correspondence is birational. In this study, we introduce the $k$-gradients varieties and analyze their main properties. We provide effective algorithms for recovering a hypersurface from its Hessian variety, for degree $3$ and $n\geq 1$, and for degree $4$ and $n$ even

Temporally-aware algorithms for the classification of anuran sounds

Several authors have shown that the sounds of anurans can be used as an indicator of climate change. Hence, the recording, storage and further processing of a huge number of anuran sounds, distributed over time and space, are required in order to obtain this indicator. Furthermore, it is desirable to have algorithms and tools for the automatic classification of the different classes of sounds. In this paper, six classification methods are proposed, all based on the data-mining domain, which strive to take advantage of the temporal character of the sounds. The definition and comparison of these classification methods is undertaken using several approaches. The main conclusions of this paper are that: (i) the sliding window method attained the best results in the experiments presented, and even outperformed the hidden Markov models usually employed in similar applications; (ii) noteworthy overall classification performance has been obtained, which is an especially striking result considering that the sounds analysed were affected by a highly noisy background; (iii) the instance selection for the determination of the sounds in the training dataset offers better results than cross-validation techniques; and (iv) the temporally-aware classifiers have revealed that they can obtain better performance than their nontemporally-aware counterparts.Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain): excellence eSAPIENS number TIC 570

Calibración de una instalación experimental para la determinación de la viscosidad de combustibles de automoción en función de la temperatura

[ES] Diseño y calibración de un viscosímetro experimental para la caracterización de diferentes combustibles a lo largo de un rango determinado de temperaturas.[EN] Design and calibration of an experimental viscometer for the characterization of different fuels over a range of temperatures.Sendra Martín, J. (2019). Calibración de una instalación experimental para la determinación de la viscosidad de combustibles de automoción en función de la temperatura. Universitat Politècnica de València. http://hdl.handle.net/10251/120114TFG

Modelling SME Commercial Lines

Treballs Finals del Màster de Ciències Actuarials i Financeres, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2015-2016, Tutora: Catalina Bolancé LosillaThis study examines an insurer database coming from Small and Medium Enterprises, SME, and suggests different types for modelling their claim cost. Due to data has a small number of policies compared to Motor line of business, a transformation is done and number of claims and claim costs are grouped depending on which part of SME is affected by the claim: Building or Content. Moreover, it is created an Aggregate claim data as the sum of the previous two. After doing this transformation to data; Building, Content and Aggregate claim cost are analysed using General Linear Models, GLM. For this study, the possibility to have a claim, the claim number and the claim cost are taking as a dependent random variables in the proposed models

Fast Optical Beamforming Architectures for Satellite-based Applications

Photonic technology o¿ers an alternative implementation for the control of phased array antennas providing large time bandwidth products and low weight, ¿exible feeding networks. Measurements of an optical beamforming network for phased array antennas with fast beam steering operation for space scenarios are presented. Experimental results demonstrate fast beam steering between 4 and 8 GHz without beam squintVidal Rodriguez, B.; Mengual, T.; Martí Sendra, J. (2012). Fast Optical Beamforming Architectures for Satellite-based Applications. Advances in Optical Technologies. 2012:1-5. doi:10.1155/2012/385409S15201

Gigabit point to multipoint backhaul using Q-band

© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper defines a Q-band point to multipoint backhaul architecture including Q-band disruptive technology that provides multi-gigabit capacity in a cost-effective manner as proposed in the EU FP7 SARABAND project. The small-scale field-trial of the network platform providing Gigabit Ethernet communication is also described.The European Commission is gratefully acknowledged for partial funding of the ICT-2011-288267 SARABAND project in the 7th Framework Programme.Vilar Mateo, R.; Martí Sendra, J.; Magne, F. (2014). Gigabit point to multipoint backhaul using Q-band. En European Conference on Networks and Communications Bologna, Italy, June 23/26, 2014. Institute of Electrical and Electronics Engineers (IEEE). 1-2. http://hdl.handle.net/10251/62767S1

Does institutional quality affect the level of entrepreneurial success differently across the entrepreneurship distribution?

The phenomenon of entrepreneurship has driven much of the attention of academics, practitioners and policy makers. A correct and deep understanding of all the different conditions affecting entrepreneurship rates will advance in the establishment of useful measures that increase entrepreneurial success. The vast majority of the literature on the effect of institutional quality on entrepreneurship has been investigated based on average effects. However, how the impact of institutional quality on the level of entrepreneurship varies with the conditional distribution of entrepreneurship is still poorly understood. The present study attempts to fill the research gaps in this field. In order to examine the impact of institutional quality on entrepreneurship at different entrepreneurship levels, the fuzzy set qualitative comparative analysis approach is employed. Results show that entrepreneurial success is determined by the combination of the following conditions of institutional quality: voice accountability, political stability, regulatory quality and rule of law. Implications and future research directions are discussed. It would be interesting to analyze in future studies the motivation to become an entrepreneur, both theoretically and empirically, differentiating between opportunity and necessity entrepreneurship

CO2 Concentration and Occupants’ Symptoms in Naturally Ventilated Schools in Mediterranean Climate

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO2 concentration was measured in two di erent periods, winter and midseason, to study the impact of the di erent levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and e ects on their health. The mean n50 values are about 7 h-1, whereas the average CO2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed

Animal Sound Classification using Sequential Classifiers

Several authors have shown that the sounds of anurans can be used as an indicator of climate change. But the recording, storage and further processing of a huge number of anuran’s sounds, distributed in time and space, are required to obtain this indicator. It is therefore highly desirable to have algorithms and tools for the automatic classification of the different classes of sounds. In this paper five different classification methods are proposed, all of them based on the data mining domain, which try to take advantage of the sound sequential behaviour. Its definition and comparison is undertaken using several approaches. The sequential classifiers have revealed that they can obtain a better performance than their non-sequential counterpart. The sliding window with an underlying decision tree has reached the best results in our tests, even overwhelming the Hidden Markov Models usually employed in similar applications. A quite remarkable overall classification performance has been obtained, a result even more relevant considering the low quality of the analysed sounds.Junta de Andalucía TIC-570