DSpace Collection:
http://hdl.handle.net/2117/3055
2014-09-16T00:55:57ZConsiderations about the relationship between the time dedicated by the students and the academic performance in a course on digital electronics
http://hdl.handle.net/2117/22798
Title: Considerations about the relationship between the time dedicated by the students and the academic performance in a course on digital electronics
Authors: Jordana Barnils, José; Sánchez Robert, Francesc Josep
Abstract: The delivery of new degree courses at the university means that subjects are designed so that students will spend a certain period of study, according to the credits which are assigned. The course Digital Circuits and Systems, which is taught in the first semester of second year degrees of Telecommunication Systems and Telematics Engineering at the EETAC (Escola d’Enginyeria de Telecomunicació i Aeronàutica de Castelldefels), has 6 ECTS, equivalent to about 150 hours of student’s work.Embrollo político en NNUU por dimensiones de la sostenibilidad
http://hdl.handle.net/2117/22021
Title: Embrollo político en NNUU por dimensiones de la sostenibilidad
Authors: Xercavins, JosepStability of nonlinear teleoperators using PD controllers without velocity measurements
http://hdl.handle.net/2117/22305
Title: Stability of nonlinear teleoperators using PD controllers without velocity measurements
Authors: Nuño, Emmanuel; Basañez Villaluenga, Luis; Lopez Franco, Carlos; Arana Daniel, Nancy
Abstract: This paper presents two Proportional-Derivative (PD) like controllers for nonlinear bilateral teleoperation systems. Compared to previous controllers of this kind, these schemes do not make use of velocity measurements. Under the assumptions that the human operator and the environment define passive maps from velocity to force, both controllers can ensure boundedness of velocities and position error. Moreover, in the case that the human and environment forces are zero, the controllers ensure velocity and position synchronization. Furthermore, the paper also presents a generalization to the case of teleoperation of networks of multiple robots. Simulations and real experiments, comparing the performance on free motion and interacting with a stiff wall, support the performance of the reported schemes. The experiments have been performed using two 3-degree-of-freedom nonlinear manipulators.Diffraction control of reflected beam by chirped mirror
http://hdl.handle.net/2117/22805
Title: Diffraction control of reflected beam by chirped mirror
Authors: Cheng, Yu Chieh; Peckus, Martynas; Kicas, S.; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, R.; Staliunas, Kestutis
Abstract: We propose and demonstrate a novel functionality of chirped mirror for monochromatic light beams: a diffraction control in reflections resulting in focusing or imaging of beams. The chirped mirrors, commonly used for manipulating temporal profiles of pulses, here are applied for manipulating the spatial dispersion of a monochromatic beam. By penetrating into dielectric layers of chirped mirror, the monochromatic beam experiences the negative diffraction, therefore the beam diverge propagating in front and behind the structure in normal diffraction region can be compensated inside this structure with negative diffraction. The result is focusing or imaging of the reflected beam from a flat interface of chirped mirror without optical axis.Characterization of patients with different ventricular ejection fractions using blood pressure signal analysis
http://hdl.handle.net/2117/22308
Title: Characterization of patients with different ventricular ejection fractions using blood pressure signal analysis
Authors: Arcentales, Andrés; Voss, Andreas; Caminal Magrans, Pere; Bayes-Genis, Antoni; Domingo, Mar Teresa; Giraldo Giraldo, Beatriz
Abstract: Ischemic and dilated cardiomyopathy are associated with disorders of myocardium. Using the blood pressure (BP) signal and the values of the ventricular ejection fraction, we obtained parameters for stratifying cardiomyopathy patients as low- and high-risk. We studied 48 cardiomyopathy patients characterized by NYHA =2: 19 patients with dilated cardiomyopathy (DCM) and 29 patients with ischemic cardiomyopathy (ICM). The left ventricular ejection fraction (LVEF) percentage was used to classify patients in low risk (LR: LVEF > 35%, 17 patients) and high risk (HR: LVEF = 35%, 31 patients) groups. From the BP signal, we extracted the upward systolic slope (BP sl), the difference between systolic and diastolic BP (BPA), and systolic time intervals (STI). When we compared the LR and HR groups in the time domain analysis, the best parameters were standard deviation (SD) of 1=STI, kurtosis (K) of BPsl, and K of BPA. In the frequency domain analysis, very low frequency (VLF) and high frequency (HF) bands showed statistically significant differences in comaprisons of LR and HR groups. The area under the curve of power spectral density was the best parameter in all classifications, and particularly in the very-low-and high- frequency bands (p < 0.001). These parameters could help to improve the risk stratification of cardiomyopathy patients.Nonlinear equations for fractional Laplacians, I: Regularity, maximum principles, and Hamiltonian estimates
http://hdl.handle.net/2117/22391
Title: Nonlinear equations for fractional Laplacians, I: Regularity, maximum principles, and Hamiltonian estimates
Authors: Cabré Vilagut, Xavier; Sire, Yannick
Abstract: This is the first of two articles dealing with the equation (-)sv = f (v) in Rn, with s ¿ (0,1), where (-)s stands for the fractional Laplacian — the in¿nitesimal generator of a Lévy process. This equation can be realized as a local linear degenerate elliptic equation in Rn+1+ together with a nonlinear Neumann boundary condition on ¿Rn+1 + =Rn.
In this ¿rst article, we establish necessary conditions on the nonlinearity f to admit certain type of solutions, with special interest in bounded increasing solutions in all of R. These necessary conditions (which will be proven in a follow-up paper to be also suficient for the existence of a bounded increasing solution) are derived from an equality and an estimate involving a Hamiltonian — in the spirit of a result of Modica for the Laplacian. Our proofs are uniform ass ¿1, establishing in the limit the corresponding known results for the Laplacian.
In addition, we study regularity issues, as well as maximum and Harnack principles associated to the equation.Numerical bifurcation methods and their application to fluid dynamics: analysis beyond simulation
http://hdl.handle.net/2117/21331
Title: Numerical bifurcation methods and their application to fluid dynamics: analysis beyond simulation
Authors: Dijkstra, Hendrik; Wubs, Fred W.; Cliffe, Andrew K.; Doedel, Eusebius J.; Dragomirescu, Ioana Florica; Eckhardt, Bruno; Gelfgat, Alexander Yu; Hazel, Andrew L.; Lucarini, Valerio; Salinger, Andrew G.; Phipps, Erik T.; Sánchez Umbría, Juan; Schuttelaars, Henk M.; Tuckerman, Laurette S.; Thiele, Uwe
Abstract: We provide an overview of current techniques and typical applications of numerical bifurcation analysis in fluid dynamical problems. Many of these problems are characterized by high-dimensional dynamical systems which undergo transitions as parameters are changed. The computation of the critical conditions associated with these transitions, popularly referred to as 'tipping points', is important for understanding the transition mechanisms. We describe the two basic classes of methods of numerical bifurcation analysis, which differ in the explicit or implicit use of the Jacobian matrix of the dynamical system. The numerical challenges involved in both methods are mentioned and possible solutions to current bottlenecks are given. To demonstrate that numerical bifurcation techniques are not restricted to relatively low-dimensional dynamical systems, we provide several examples of the application of the modern techniques to a diverse set of fluid mechanical problems.Design, management and comissioning of a utility connected microgrid based on IEC 61850
http://hdl.handle.net/2117/20982
Title: Design, management and comissioning of a utility connected microgrid based on IEC 61850
Authors: Ruiz Alvarez, A.; Colet Subirachs, A.; Gomis Bellmunt, Oriol; Fernández Mola, José María; Alvarez Cuevas, F.; López Mestre, Joaquim; Sudrià Andreu, Antoni
Abstract: This paper presents an approach to microgrid
automation. The microgrid is composed of three different nodes connected to the public electric grid, which are hardware
emulated with back-to-back converters. The microgrid is a flexible and weather independent test bed for testing different
control algorithms. The intelligence of the automation system is split in three hierarchical layers: the RMU layer, the iNode
layer and the iSocket layer. Communications among iNode and iSockets are according IEC 61850 standard.
The aims of the project is to comission a set of technologies and acquire experience in microgrid automation, IEC 61850
communications and power control algorithms in DER systems.International briefing 31: training and development in Mexico
http://hdl.handle.net/2117/21761
Title: International briefing 31: training and development in Mexico
Authors: Barrera Villar, Alejandro; Llinàs Audet, Francisco Javier; Escardíbul Serra, Josep Oriol
Abstract: This paper examines training policies in Mexico. We present the main characteristics of Mexico's educational and training systems, examining both public and private policies, and analyse how they impact on productivity and development. We highlight Mexican efforts overall in promoting education and training and conclude that greater levels of investment are required to boost skills and productivity. In short, both the level of education of the active population and the percentage of trained employees need to be increased.Estructuras A-infinito en la opérada de cactus
http://hdl.handle.net/2117/22097
Title: Estructuras A-infinito en la opérada de cactus
Authors: Gálvez Carrillo, Maria Immaculada; Lombardi, Leandro; Tonks, Andrew
Abstract: Diversas versiones de la opérada de cactus inicialmente definida por Voronov han sido estudiadas. Es conocida su equivalencia débil con la opérada de pequeños discos. Se conoce pues que la opérada de cactus admite una acción de la opérada de Gerstenhaber salvo homotopía. En este proyecto, nuestro objetivo es obtener una realización explícita de dicha acción. Por el momento, hemos construido una acción explícita de la opérada A8 en la opérada de cactus, que presentamos en este pósterJ2 effect and elliptic inclined periodic orbits in the collision three-body problem
http://hdl.handle.net/2117/21117
Title: J2 effect and elliptic inclined periodic orbits in the collision three-body problem
Authors: Barrabes, Esther; Cors Iglesias, Josep Maria; Pinyol, Conxita; Soler Villanueva, Jaume
Abstract: The existence of a new class of inclined periodic orbits of the collision restricted
three{body problem is shown. The symmetric periodic solutions found are perturbations of elliptic
kepler orbits and they exist only for special values of the inclination and are related to the motion
of a satellite around an oblate planet.Computing a visibility polygon using few variables
http://hdl.handle.net/2117/24062
Title: Computing a visibility polygon using few variables
Authors: Barba, Luis; Korman Cozzetti, Matías; Langerman, Stefan; Silveira, Rodrigo Ignacio
Abstract: We present several algorithms for computing the visibility polygon of a simple polygon P of n vertices (out of which r are reflex) from a viewpoint inside P, when P resides in read-only memory and only few working variables can be used. The first algorithm uses a constant number of variables, and outputs the vertices of the visibility polygon in O (n (r) over bar) time, where (r) over bar denotes the number of reflex vertices of P that are part of the output. Whenever we are allowed to use O(s) variables, the running time decreases to O (nr/2(s) + n log(2) r) (or O (nr/2(s) + n log r) randomized expected time), where s is an element of O (log r). This is the first algorithm in which an exponential space-time trade-off for a geometric problem is obtained. (C) 2014 Elsevier B.V. All rights reserved.2014-09-15T19:28:08ZStudy of the recycled aggregates nature's influence on the aggregate-cement paste interface and ITZ
http://hdl.handle.net/2117/24061
Title: Study of the recycled aggregates nature's influence on the aggregate-cement paste interface and ITZ
Authors: Sidorova, Anna; Vázquez Ramonich, Enric; Barra Bizinotto, Marilda; Roa Rovira, Joan Josep; Jiménez Piqué, Emilio
Abstract: Today it is highly recognized that the structure of the cement paste matrix close to the aggregates, is different from the rest of the cement paste. This investigation compares the possible interfacial transition zone (ITZ) formation by means of the nanoindentation test and Scanning Electron Microscopy (SEM), with aggregate inclusions of three different natures: limestone (NA), recycled concrete aggregate (RCA) and recycled ceramic aggregate (RC). This study demonstrated that nature of the aggregate and the w/c ratio conditions determines the micro structural characteristics of the aggregate–cement paste interface and the mechanical properties of the ITZ.2014-09-15T19:18:46ZGeodesic order types
http://hdl.handle.net/2117/24060
Title: Geodesic order types
Authors: Aichholzer, Oswin; Korman Cozzetti, Matías; Pilz, Alexander; Vogtenhuber, Birgit
Abstract: The geodesic between two points a and b in the interior of a simple polygon P is the shortest polygonal path inside P that connects a to b. It is thus the natural generalization of straight line segments on unconstrained point sets to polygonal environments. In this paper we use this extension to generalize the concept of the order type of a set of points in the Euclidean plane to geodesic order types. In particular, we show that, for any set S of points and an ordered subset of at least four points, one can always construct a polygon P such that the points of define the geodesic hull of S w.r.t. P, in the specified order. Moreover, we show that an abstract order type derived from the dual of the Pappus arrangement can be realized as a geodesic order type.2014-09-15T19:00:52ZOn the modeling and real-time control of urban drainage systems: A survey
http://hdl.handle.net/2117/24059
Title: On the modeling and real-time control of urban drainage systems: A survey
Authors: García Gutiérrez, Luis Antonio; Escobar, Eduardo; Barreiro Gomez, Julian; Quijano Silva, Nicanor; Ocampo-Martínez, Carlos; Téllez, Duván
Abstract: Drainage networks are complex systems composed by several processes including recollection, transport, storing, treatment, and releasing the water to a receiving environment. The way Urban Drainage Systems (UDS) manage wastewater is through the convenient handling of active elements such as gates (redirection and/or retention), storing tanks, and pumping stations, when needed. Therefore, modeling and control of UDS basically consists in knowing and representing the (dynamical) behavior of these elements and managing them properly in order to achieve a given set of control objectives, such as minimization of flooding in streets or maximization of treated wastewater in the system. Given the large number of elements composing an UDS and the interaction between them, management and control strategies may depend on highly complex system models, which implies the explicit difficulty for designing real-time control (RTC) strategies. This paper makes a review of the models used to describe, simulate, and control UDS, proposes a revision of the techniques and strategies commonly used for the control UDS, and finally compares several control strategies based on a case study.2014-09-15T18:19:31Z