# UPCommons

UPCommons, el portal d'accés obert al coneixement de la UPC, està format pel conjunt de dipòsits institucionals oberts de la UPC i té com a missió garantir la preservació de la producció docent i de recerca cientificotècnica de la Universitat, maximitzant-ne la visibilitat i, conseqüentment, incrementant-ne l’impacte en la docència i la recerca de tot el món.
Actualitzat: fa 37 minuts 6 segons

### Effects of temporal correlations in social multiplex networks

dv., 01/26/2018 - 16:22
Effects of temporal correlations in social multiplex networks Starnini, Michele; Baronchelli, Andrea; Pastor Satorras, Romualdo Multi-layered networks represent a major advance in the description of natural complex systems, and their study has shed light on new physical phenomena. Despite its importance, however, the role of the temporal dimension in their structure and function has not been investigated in much detail so far. Here we study the temporal correlations between layers exhibited by real social multiplex networks. At a basic level, the presence of such correlations implies a certain degree of predictability in the contact pattern, as we quantify by an extension of the entropy and mutual information analyses proposed for the single-layer case. At a different level, we demonstrate that temporal correlations are a signature of a ‘multitasking’ behavior of network agents, characterized by a higher level of switching between different social activities than expected in a uncorrelated pattern. Moreover, temporal correlations significantly affect the dynamics of coupled epidemic processes unfolding on the network. Our work opens the way for the systematic study of temporal multiplex networks and we anticipate it will be of interest to researchers in a broad array of fields.
Categories: Novetats

### A study of human scale public space in the chinese context: under the influence of people’s participation

dv., 01/26/2018 - 16:19
A study of human scale public space in the chinese context: under the influence of people’s participation Zhao, Yuke Màster universitari en Estudis Avançats en Arquitectura: Urbanisme
Categories: Novetats

### Wireless-optical network convergence: enabling the 5G architecture to support operational and end-user services

dv., 01/26/2018 - 15:52
Wireless-optical network convergence: enabling the 5G architecture to support operational and end-user services Tzanakaki, Anna; Anastasopoulos, Markos; Berberana, Ignacio; Syrivelis, Dimitris; Flegkas, Paris; Korakis, Thanasis; Camps Mur, Daniel; Seyfettin Demirkol, Ilker; Gutiérrez Terán, Jesús; Grass, Eckhard; Wei, Qing; Pateromichelakis, Emmanouil; Vucic, Nikola; Fehske, Albrecht; Grieger, Michael; Eiselt, Michael; Bartelt, Jens; Fettweis, Gerhard; Lyberopoulos, George; Theodoropoulou, Eleni; Simeonidou, Dimitra This article presents a converged 5G network infrastructure and an overarching architecture to jointly support operational network and end-user services, proposed by the EU 5G PPP project 5G-XHaul. The 5G-XHaul infrastructure adopts a common fronthaul/backhaul network solution, deploying a wealth of wireless technologies and a hybrid active/passive optical transport, supporting flexible fronthaul split options. This infrastructure is evaluated through a novel modeling. Numerical results indicate significant energy savings at the expense of increased end-user service delay. © 2017 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.
Categories: Novetats

### Silicon solar cells with heterojunction emitters and laser processed base contacts

dv., 01/26/2018 - 15:41
Silicon solar cells with heterojunction emitters and laser processed base contacts Jin, Chen; Martín García, Isidro; López Rodríguez, Gema; Harrison, S.; Masmitjà Rusiñol, Gerard; Ortega Villasclaras, Pablo Rafael; Alcubilla González, Ramón In this work, we report on a novel structure of Interdigitated Back-Contacted (IBC) solar cells on c-Si p-type substrates that combines laser processed homojunction base contacts and silicon heterojunction (SHJ) emitters. These hybrid devices which can lead to potential benefits in device processing and/or conversion efficiency. In the proposed fabrication process special attention has been paid to the compatibility of both involved technologies: silicon heterojunction and laser doping from dielectric films. In particular, we focus on the surface passivation obtained by the heterojunction emitter after removing the aluminum oxide/silicon carbide (Al2O3/SiCx) layer stack needed for the laser doping process and previously deposited on the c-Si surface. A severe passivation degradation after plasma et ching process to remove the top SiCx film is observed, despite leaving the Al2O3 film on the c-Si surface. Based on high-frequency capacitance-voltage characterization, an increase in the interface state density and a strong impact on the fixed charge density is deduced. Next, in order to choose an optimized metallization technology that could simultaneously contact both the ITO film and the p+ laser processed regions, we evaluate the contact quality of Titanium and Aluminum on ITO. Results show that Titanium is a better option with a specific contact resistance of 1.1 mohm cm2. Finally, finished hybrid IBC solar cells with conversion efficiencies in the 18-19% range are reported.
Categories: Novetats

### Unravelling the effects of mechanical physiological conditioning on cardiac adipose tissue-derived progenitor cells in vitro and in silico

dv., 01/26/2018 - 15:32
Unravelling the effects of mechanical physiological conditioning on cardiac adipose tissue-derived progenitor cells in vitro and in silico Llucía Valldeperas, Aida; Bragós Bardia, Ramon; Soler Botija, Carolina; Roura Ferrer, Santiago; Gálvez Montón, Carolina; Prat Vidal, Cristina; Perea Gil, Isaac; Bayés Genis, Antoni Mechanical conditioning is incompletely characterized for stimulating therapeutic cells within the physiological range. We sought to unravel the mechanism of action underlying mechanical conditioning of adipose tissue-derived progenitor cells (ATDPCs), both in vitro and in silico. Cardiac ATDPCs, grown on 3 different patterned surfaces, were mechanically stretched for 7 days at 1 Hz. A custom-designed, magnet-based, mechanical stimulator device was developed to apply ~10% mechanical stretching to monolayer cell cultures. Gene and protein analyses were performed for each cell type and condition. Cell supernatants were also collected to analyze secreted proteins and construct an artificial neural network. Gene and protein modulations were different for each surface pattern. After mechanostimulation, cardiac ATDPCs increased the expression of structural genes and there was a rising trend on cardiac transcription factors. Finally, secretome analyses revealed upregulation of proteins associated with both myocardial infarction and cardiac regeneration, such as regulators of the immune response, angiogenesis or cell adhesion. To conclude, mechanical conditioning of cardiac ATDPCs enhanced the expression of early and late cardiac genes in vitro. Additionally, in silico analyses of secreted proteins showed that mechanical stimulation of cardiac ATDPCs was highly associated with myocardial infarction and repair.
Categories: Novetats

### Equivalences and Black-Box Separations of Matrix Diffie-Hellman Problems

dv., 01/26/2018 - 14:21
Equivalences and Black-Box Separations of Matrix Diffie-Hellman Problems Villar Santos, Jorge Luis In this paper we provide new algebraic tools to study the relationship between different Matrix Diffie-Hellman (MDDH) Problems, which are recently introduced as a natural generalization of the so-called Linear Problem. Namely, we provide an algebraic criterion to decide whether there exists a generic black-box reduction, and in many cases, when the answer is positive we also build an explicit reduction with the following properties: it only makes a single oracle call, it is tight and it makes use only of operations in the base group. It is well known that two MDDH problems described by matrices with a different number of rows are separated by an oracle computing certain multilinear map. Thus, we put the focus on MDDH problems of the same size. Then, we show that MDDH problems described with a different number of parameters are also separated (meaning that a successful reduction cannot decrease the amount of randomness used in the problem instance description). When comparing MDDH problems of the same size and number of parameters, we show that they are either equivalent or incomparable. This suggests that a complete classification into equivalence classes could be done in the future. In this paper we give some positive and negative partial results about equivalence, in particular solving the open problem of whether the Linear and the Cascade MDDH problems are reducible to each other. The results given in the paper are limited by some technical restrictions in the shape of the matrices and in the degree of the polynomials defining them. However, these restrictions are also present in most of the work dealing with MDDH Problems. Therefore, our results apply to all known instances of practical interest.
Categories: Novetats

### Diseño de una célula robotizada en una instalación

dv., 01/26/2018 - 13:55
Diseño de una célula robotizada en una instalación Cela Pascual, Roberto El presente documento es el anteproyecto del diseño y posterior montaje de una célula robotizada parte de un proceso de fabricación en la industria del sector del automóvil, en él se define el apartado eléctrico y electrónico dirigido al departamento de ingeniería de procesos para proceder a su valoración. Se partirá de unas condiciones previamente establecidas por dicho departamento y de un entorno determinado. Se determinan todos los elementos necesarios para su funcionamiento basándonos en premisas técnicas impuestas por el departamento. Incluye el dimensionamiento eléctrico de la instalación y la situación, así como los elementos que deben incluirse en los armarios eléctricos. Se desarrolla un análisis del proceso mediante el cual se analizará la posición de los robots (y en consecuencia el resto de elementos) así como un estudio de tiempos para alcanzar un diseño de instalación el cual sea óptimo y cumpla las necesidades del cliente. En referencia al Layout de la instalación, se mostrará una vista en planta de ésta en la que se representará la ubicación de los robots, armarios de alimentación de robot, armarios eléctricos, útiles de manejo, elementos de manejo, etc. Desde esta vista, se podrá observar el radio de acción de cada robot y con el fin de asegurar que no existan colisiones entre robots que trabajan en el mismo útil, se definirá mediante un diagrama cuál es su funcionamiento. En el proyecto se define una red de trabajo a nivel de campo de todos los elementos que la componen tales como PLC’s, islas de válvulas, switches, HMI, etc. Mediante los grafcets se observa cómo estará definida la secuencia de trabajo en los diferentes útiles y como se estructurarán los programas de robot. Finalmente se incluye un manual de funcionamiento de la instalación y se realizará un impacto medioambiental.
Categories: Novetats

### Prosthetic leg and knee joint design and development

dv., 01/26/2018 - 13:38
Prosthetic leg and knee joint design and development Bubas, Tomasz; Cots Ferrer, Raül; Mir Vilaró, Helena; Xantippe Plaetinck, Eva; Quer Òdena, Marina Currently on the market, there is a significant gap on the field of prosthetic legs for children. That is why this report focuses on improving a prosthetic leg for through-knee amputated children from 4 to 10 years old, which should enable them to perform the daily activities. The scope of work includes an extended exploration about the field of study, a deep market research about existing components, the findings of current problems with prostheses, the translation of the problems into requirements and, eventually, the development of the solution proposed. The final result of this project is an opening idea which includes the design of a knee joint, socket and pylon. The advantages of the expounded design compared to other currently products are essentially the modularity, the adaptability of the leg to the patient, the increase of freedom of movements and, mainly, the utilisation of the space to include technology to have a more natural gate. The design is described by sketches, 3D models and a 3D printed prototype. Finally, in the project are also specified some future plans for further development and improvement.
Categories: Novetats

dv., 01/26/2018 - 13:31
Evaluation of AUV-borne ADCP measurements in different navigation modes Nogueras Cervera, Marc; Antonijuan Rull, Josefina; Masmitjà Rusiñol, Ivan; Río Fernandez, Joaquín del Most Autonomous Underwater Vehicles (AUVs) mount an Acoustic Doppler Current Profilers (ADCP). Data from this sensor are rarely used in scientific studies due to the complexity of its processing and the lack of validation. Aside of that, AUV operators lack a set of guidelines regarding the optimal navigation modes and AUV-borne ADCP configurations to obtain the most accurate data possible. This study compares 12.6 hours of AUV-borne ADCP currents measurements, taken in different AUV navigation modes and ADCP configurations, to those of a moored AWAC. Results show RMS errors of 5 cm/s for U (East) and V (North) measures and of 2 cm/s for vertical currents measures for most of the navigation modes. Cell size is found to be the most influential parameter in data accuracy and yo-yo type of surveys are proved to be as accurate as constant depth ones.
Categories: Novetats

### Sensat de variables mitjançant un terminal

dv., 01/26/2018 - 13:23
Categories: Novetats

### Modular LED Lamp

dv., 01/26/2018 - 13:21
Modular LED Lamp Aedma, Andra; Petersen, Nils; Rzeznik, Piotr; Ritter, Norbert; González Alen, David The aim of this project is to analyse issues that are related to energy-saving LED lighting and to develop an innovative product meeting defined objectives. LED lamp should change colours, fit to the universal socket, has low cost and innovative design. In particular, the analysis included the currently used technologies and similar products placed on the market. The result is a Modular LED lamp prototype which is able to change colours and brightness. Besides this, the project contains the topics that are necessary for launching the final product into the market, e.g. schemes, branding and other problems connected with sales. The new LED lamp allows potential customers to run their business complying with sustainability policy requirements related to energy consumption, environmental and ethical issues, as well as with people’s well-being.
Categories: Novetats

### Plan de contingencias para el Golfo de Sant Jordi por vertidos de hidrocarburos desde la plataforma petrolífera Casablanca

dv., 01/26/2018 - 13:08
Plan de contingencias para el Golfo de Sant Jordi por vertidos de hidrocarburos desde la plataforma petrolífera Casablanca Rojas Domènech, Neus Considerant el risc que podria suposar a les costes del mar balear un vessament d’hidrocarbur originat a la Plataforma Casablanca, en el present treball es busca estudiar quines serien les conseqüències d’un vessament d’aquest caire. D’aquesta manera, amb l’ajuda del Model GNOME, es busca avaluar quines són les zones de la costa que presenten més opcions de ser afectades així com la quantitat d’hidrocarbur amb la que haurien de treballar en cas d’afectació. Per altra banda, també es busca analitzar el temps que restaria entre l’origen del vessament i l’arribada d’aquest a la costa. Amb això, es busca determinar quines són les zones de la costa que presenten un major risc d’afectació davant d’un succés d’aquest estil per tal de poder conèixer en quins punts s’hauria de realitzar una actuació amb més urgència, per tal de poder protegir-les de manera adequada i evitar problemes majors. Per a fer aquest anàlisi, s’han usat dades de models numèrics contrastats per obtenir els forçaments hidrodinàmics i atmosfèrics. L’aproximació utilitzada s’ha basat en un anàlisi probabilístic a partir d’un conjunt de simulacions, cosa que ha permès establir patrons estacionals.; Considering the risk that could lead to the shores of the Balearic Sea caused by a spill in Casablanca platform, it is considered to study which would be the consequences of a spill of this nature. Thus, with the help of Model GNOME, it is pretended to assess which areas of the coast would have more options, taking into account the amount of oil that should work in the event of impact. On the other hand, it is needed to analyze the time remaining between the source of the spill and the arrival on the coast. With this, we seek to determine which areas of the coast have a greater risk in front of an event of this kind in order to know at which points should make action more urgently in order to protect it properly and avoid greater problems. To do this analysis, it has been used data from numerical models which provides hydrodynamic and atmospheric forcing. The approach used is based on a probabilistic analysis, taking into account a set of simulations, which have allowed to establish seasonal patterns.
Categories: Novetats

### Funcionalización de estructuras porosas de titanio mediante polímeros recombinantes de tipo elastina

dv., 01/26/2018 - 12:54
Categories: Novetats

### Optimización de la síntesis guiada de soluciones conceptuales trazabilidad de los requerimientos funcionales: caso de estudio de un molino de cuchillas

dv., 01/26/2018 - 12:53
Categories: Novetats

### Desenvolupament d'un projecte de rec artificial per a un circuit de proves de motor

dv., 01/26/2018 - 12:27
Desenvolupament d'un projecte de rec artificial per a un circuit de proves de motor Busquets Lobera, Sergi El Circuit de Barcelona-Catalunya presenta la necessitat d’establir un sistema d’aspersió d’aigua que permeti realitzar-hi proves de motor simulant les mateixes condicions d’un dia de pluja a l’asfalt de la pista. Al present treball es definiran el conjunt de processos involucrats al sistema d’aspersió d’aigua, des de la recollida d’aigües reciclades de pluja, a la instal·lació de bombeig, el tractament físic i químic de l’aigua, el procés de rec i la reutilització de l’aigua utilitzada. Totes les etapes seran projectades amb l’objectiu de minimitzar, tot el possible, l’impacte sobre els emplaçaments existents, reduint al màxim la necessitat de recursos externs, tals com l’aigua de xarxa. Finalment, un cop establerts els conjunt de condicionants tècnics requerits per poder assolir el conjunt d’objectius inicialment plantejats, s’efectuarà un estudi de viabilitat econòmica del mateix per poder arribar a determinar l’amortització i rendiment de les noves instal·lacions i la possible implantació a altres circuits de competicions de motor, establint una sèrie d’estàndards que permetin valorar la viabilitat d’un sistema similar en funció de les dimensions i horografia del terreny dels altres circuits de competicions de motor.
Categories: Novetats

### Kirkwood gaps and diffusion along mean motion resonances in the restricted planar three-body problem

dc., 01/24/2018 - 14:19
Kirkwood gaps and diffusion along mean motion resonances in the restricted planar three-body problem Guàrdia Munarriz, Marcel; Kaloshin, Vadim; Fejoz, J.; Roldan, Pablo We study the dynamics of the restricted planar three-body problem near mean motion resonances, i.e. a resonance involving the Keplerian periods of the two lighter bodies revolving around the most massive one. This problem is often used to model Sun--Jupiter--asteroid systems. For the primaries (Sun and Jupiter), we pick a realistic mass ratio µ=10-3 and a small eccentricity e0>0. The main result is a construction of a variety of non local diffusing orbits which show a drastic change of the osculating (instant) eccentricity of the asteroid, while the osculating semi major axis is kept almost constant. The proof relies on the careful analysis of the circular problem, which has a hyperbolic structure, but for which diffusion is prevented by KAM tori. We verify certain non-degeneracy conditions numerically. Based on the work of Treschev, it is natural to conjecture that diffusion time for this problem is ~-ln(µe0)µ3/2e0. We expect our instability mechanism to apply to realistic values of e0 and we give heuristic arguments in its favor. If so, the applicability of Nekhoroshev theory to the three-body problem as well as the long time stability become questionable. It is well known that, in the Asteroid Belt, located between the orbits of Mars and Jupiter, the distribution of asteroids has the so-called Kirkwood gaps exactly at mean motion resonances of low order. Our mechanism gives a possible explanation of their existence. To relate the existence of Kirkwood gaps with Arnold diffusion, we state a conjecture on its existence for a typical $\eps$-perturbation of the product of a pendulum and a rotator. Namely, we predict that a positive conditional measure of initial conditions concentrated in the main resonance exhibits Arnold diffusion on time scales $\frac{- \ln \eps}{\eps^{2}}$
Categories: Novetats

### UNFOLD: a memory-efficient speech recognizer using on-the-fly WFST composition

dc., 01/24/2018 - 14:18
UNFOLD: a memory-efficient speech recognizer using on-the-fly WFST composition Yazdani Aminabadi, Reza; Arnau Montañés, José María; González Colás, Antonio María Accurate, real-time Automatic Speech Recognition (ASR) requires huge memory storage and computational power. The main bottleneck in state-of-the-art ASR systems is the Viterbi search on a Weighted Finite State Transducer (WFST). The WFST is a graph-based model created by composing an Acoustic Model (AM) and a Language Model (LM) offline. Offline composition simplifies the implementation of a speech recognizer as only one WFST has to be searched. However, the size of the composed WFST is huge, typically larger than a Gigabyte, resulting in a large memory footprint and memory bandwidth requirements. In this paper, we take a completely different approach and propose a hardware accelerator for speech recognition that composes the AM and LM graphs on-the-fly. In our ASR system, the fully-composed WFST is never generated in main memory. On the contrary, only the subset required for decoding each input speech fragment is dynamically generated from the AM and LM models. In addition to the direct benefits of this on-the-fly composition, the resulting approach is more amenable to further reduction in storage requirements through compression techniques. The resulting accelerator, called UNFOLD, performs the decoding in real-time using the compressed AM and LM models, and reduces the size of the datasets from more than one Gigabyte to less than 40 Megabytes, which can be very important in small form factor mobile and wearable devices. Besides, UNFOLD improves energy-efficiency by orders of magnitude with respect to CPUs and GPUs. Compared to a state-of-the-art Viterbi search accelerators, the proposed ASR system outperforms by providing 31x reduction in memory footprint and 28% energy savings on average.
Categories: Novetats

### A time-domain second-order FEM model for the wave diffraction radiation problem. Validation with a semisubmersible platform

dc., 01/24/2018 - 14:12
A time-domain second-order FEM model for the wave diffraction radiation problem. Validation with a semisubmersible platform Serván Camas, Borja; Gutiérrez Romero, José Enrique; García Espinosa, Julio
Categories: Novetats

### Analysis and synthesis of control systems over wireless digital channels

dc., 01/24/2018 - 13:49
Analysis and synthesis of control systems over wireless digital channels Reza Karimi, Hamid; Niu, Yugang; Rossell Garriga, Josep Maria; Yang, Fuwen
Categories: Novetats

### Iron loss prediction using modified IEM-formula during the field weakening for permanent magnet synchronous machines

dc., 01/24/2018 - 13:45
Iron loss prediction using modified IEM-formula during the field weakening for permanent magnet synchronous machines Asef, Pedram; Bargalló Perpiñá, Ramón; lapthorn, andrew
Categories: Novetats