RECERCAT - Documents de recerca

Selecció i millora de la varietat tradicional de fesol (Phaseolus vulgaris L.) Tavella Brisa V. Memòria any 2008

Selecció i millora de la varietat tradicional de fesol (Phaseolus vulgaris L.) Tavella Brisa V. Memòria any 2008 Casañas Artigas, Francesc; Almirall Malivern, Antonio Rafael; Bosch Roura, Lluís; Romero del Castillo Shelly, Mª del Rosario; Rivera Pinzano, Ana; Sagrera, Boi Memoria anual de les activitats de selecció i millora de la varietat Tavella Brisa; Preprint

Integrating task planning and interactive learning for robots to work in human environments

Integrating task planning and interactive learning for robots to work in human environments Agostini, Alejandro Gabriel; Torras, Carme; Wörgötter, Florentin Human environments are challenging for robots, which need to be trainable by lay people and learn new behaviours rapidly without disrupting much the ongoing activity. A system that integrates AI techniques for planning and learning is hereproposed to satisfy these strong demands. Theapproach rapidly learns planning operators from few action experiences using a competitive strategy where many alternatives of cause-effect explanations are evaluated in parallel, and the most successful ones are used to generate the operators. Thesuccess of a cause-effect explanation is evaluated by a probabilistic estimate that compensates the lack of experience, producing more confident estimations and speeding up the learning in relation toother known estimates. The system operates without task interruption by integrating in the planning-learning loop a human teacher that supports the planner in making decisions. All the mechanisms are integrated and synchronized in the robot using ageneral decision-making framework. The feasibility and scalability of the architecture are evaluated in two different robot platforms: a Stäubli arm, and the humanoid ARMAR III.; Peer Reviewed; Postprint (author’s final draft)

A closer look at the sanitation ladder: issues of monitoring the sector

A closer look at the sanitation ladder: issues of monitoring the sector Giné Garriga, Ricard; Jiménez Fernández de Palencia, Alejandro; Pérez Foguet, Agustí Preprint

Transverse effective dispersion coefficients in a chemically heterogeneous medium with flow fluctuations

Transverse effective dispersion coefficients in a chemically heterogeneous medium with flow fluctuations Zavala Sánchez, Gabriela V.; Dentz, Marco; Sánchez Vila, Francisco Javier We investigate the effective transport of a sorptive solute through a chemically heterogeneous medium subject to temporal fluctuations of the flow conditions. We focus on linear instantaneous sorption, with a spatially variable retardation factor. The medium is physically homogeneous. The temporal variability of the flow is represented by a stationary random process. In this stochastic modelling framework, solute spreading is quantified by effectivedispersion coefficients. Focusing on the transverse contributions due to chemical heterogeneity and temporal fluctuations, we find enhanced transverse spreading characterized by a transverse effective dispersion coefficient that, in contrast to transport in steady state flow, evolves to adisorder-induced macroscopic value independent of local dispersion.; Peer Reviewed; Preprint

Análisis del ciclo de vida del sistema de gestión de residuos municipales de la Ciudad de México

Análisis del ciclo de vida del sistema de gestión de residuos municipales de la Ciudad de México Juárez, C.; Güereca Hernández, L. Patricia; Gassó Domingo, Santiago El Análisis del Ciclo de Vida (ACV) es una herramienta metodológica que determina lospotenciales impactos ambientales asociados con un producto o servicio, desde la extracción dela materia prima hasta su disposición final. El objetivo de este estudio es evaluar los potencialesimpactos ambientales asociados a cada uno de los proceso del sistema de gestión de residuossólidos de la Ciudad de México, mediante la aplicación del software TEAM, se evaluó lassiguientes categorías de impacto: acidificación, disminución del ozono estratosférico,eutrofización, efecto invernadero (directo, 100 años), formación de foto-oxidantes, toxicidadterrestre, efectos carcinogénicos y efectos respiratorios. Los resultados sugieren que el sistemade manejo de residuos sólidos de la Ciudad de México presenta impactos relevantes en losprocesos de vertedero controlado, vertederos no controlados y reciclado de vidrio; el procesode fabricación de compost se presenta como una opción favorable debido a que no presentaimpactos ambientales significativos. El ACV realizado sugiere la siguiente jerarquía detratamientos de residuos municipales: fabricación de compost, incineración, reciclaje y vertederocontrolado. La peor alternativa es el vertido no controlado de residuos debido a que se trata desuperficies donde los residuos son depositados de forma clandestina y no cuentan con ningúntipo de control de la contaminación.; Preprint

Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations

Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations Alados Arboledas, Lucas; Pujadas, Manuel; Wagner, F.; Rocadenbosch Burillo, Francisco; Sicard, Michaël; Guerrero Rascado, Juan Luis; Navas Guzmán, Francisco; Preissler, J.; Molero, Francisco; Tomás Martínez, Sergio; Bravo Aranda, J. A.; Comerón Tejero, Adolfo Lidar and sun-photometer measurements were performed intensively over the IberianPeninsula (IP) during the eruption of Eyjafjallaj ¨ okull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (< 1000 m) with a top height up to 11–12 km. The mean optical thicknesses associated to those layers were rather low (between 0.013 and 0.020 over the whole period). Punctually on 7 May the optical thickness reached peakvalues near 0.10. Secondly the volcanic aerosols are characterized in terms of extinction and backscatter coefficients, lidar ratios, A° ngstro¨m exponents and linear particle depolarization ratio. Lidar ratios at different sites varied between 30 and 50 sr without a marked spectral dependency. Similar extinction-related A° ngstro¨m exponents varying between 0.6 and 0.8 were observed at different sites. The temporal evolution of the backscatter-related A° ngstro¨m exponents points out a possible decrease of the volcanicparticle size as the plume moves from west to east. Particle depolarization ratioson the order of 0.06–0.08 confirmed the coexistence of both ash and non-ash particles. Additionally profiles of mass concentration were obtained with a method using the opposite depolarizing effects of ash particles (strongly depolarizing) and non-ash particles (very weakly depolarizing), and sun-photometer observations. In Granada the ash mass concentration was found approximately 1.5 higher than that of non-ash particles, and probably did not exceed the value of 200 μgm−3 during the whole event.; Peer Reviewed; Postprint (published version)

Bringing action language C+ to normative contexts: preliminary report

Bringing action language C+ to normative contexts: preliminary report Garcia Gasulla, Dario; Nieves, Juan Carlos C+ is an action language for specifying and reasoning about the e ects of actions and the persistence of facts over time. Based on it. we present CN+, an operational enhanced form of C+ designed for representing complex normative systems and integrate them easily into the semantics of the causal theory of actions. The proposed system contains a particular formalization of norms using a life-cycle approach to capture the whole normative meaning of a complex normative framework. We discuss this approach and illustrate it with examples.; Peer Reviewed; Postprint (author’s final draft)

Manual de buenas prácticas para fomentar el aprendizaje en las asignaturas de resistencia de materiales y estructuras

Manual de buenas prácticas para fomentar el aprendizaje en las asignaturas de resistencia de materiales y estructuras Suárez Arroyo, Benjamín; Rivera Amores, Juan José; Ferrer Ballester, Miquel El Manual está estructurado en tres grandes capítulos y unas consideraciones finales. Cada uno de estos capítulos trata aspectos diferentes pero complementarios. El primero nos introduce en el EEES, haciendo referencia a los diferentes modelos educativos y su incidencia en el entorno social. El segundo capítulo nos permite conocer propuestas formativas desarrolladas por diferentes profesores del Departamento de RMEE. El tercer capítulo enmarca todo lo que se ha comentado en los otros dos, mediante unas reflexiones estructuradas en cinco áreas que permiten entender cuál es el verdadero sentido de la propuesta EEES, cuál será el alcance de éste trabajo y como la afrontarán tanto los profesores como los estudiantes. Finalmente y como colofón encontramos unas consideraciones que hacen referencia a como la sociedad del siglo XXI afrontará estos cambios, tanto a nivel conceptual como estratégico.; Preprint

Rastrear proyectos, contar historias

Rastrear proyectos, contar historias Álvarez Prozorovich, Fernando V. Postprint (published version)

Pla de gestió agrícola del Parc Rural de la Torre Negra (Sant Cugat del Vallès)

Pla de gestió agrícola del Parc Rural de la Torre Negra (Sant Cugat del Vallès) Cáceres, A; Casañas Artigas, Francesc Document tècnic per la planificació de la gestió del Parc Rural; Preprint

Plec de condicions i document únic de la DOP Fesols de Santa Pau

Plec de condicions i document únic de la DOP Fesols de Santa Pau Casañas Artigas, Francesc; Almirall Malivern, Antonio Rafael; Romero del Castillo Shelly, Mª del Rosario Documents per a la obtenció de la DOP Fesols de Santa Pau; Preprint

Obtenció de la G0 i G1 de la varietat Croscat, del tipus varietal Tavella Brisa

Obtenció de la G0 i G1 de la varietat Croscat, del tipus varietal Tavella Brisa Casañas Artigas, Francesc; Almirall Malivern, Antonio Rafael; Rivera Pinzano, Ana; Fenero Artasu, Daniel Memòria activitats de millora genètica i multiplicació de llavor.; Preprint

One-step finite horizon boundary with varying control gain for event-driven networked control systems

One-step finite horizon boundary with varying control gain for event-driven networked control systems Yépez Castillo, José Gregorio; Velasco García, Manel; Martí Colom, Pau; Martín, Enric Xavier; Fuertes Armengol, José Mª Recent research has shown that event-driven control requires less samples than time-driven (periodic) control. Consequently, event-driven control applied to Networked Control Systems (NCS) is a good approach for alleviating controllers bandwidth demands and reducing overall network traffic. Following this trend, this paper presents an execution rule for event-driven networked controllers that at each jobexecution aims at postponing the next job execution while applying an appropriated controller gain considering each varying sampling interval that applies at run time. This method permits to dynamically lower the generated traffic for each networked control loop while ensuring the same or bettercontrol performance than the achieved by the periodic case.In addition, an implementation strategy capable of dealing with network induced time delays is also presented. Simulation results illustrate the operation and benefits of the presented approach.; Peer Reviewed; Postprint (author’s final draft)

Como mejorar el aprendizaje de los grados en ingeniería desde la perspectiva de los estudiantes

Como mejorar el aprendizaje de los grados en ingeniería desde la perspectiva de los estudiantes Navarro Antúnez, Ramón; Molinero Albareda, Xavier La implantación de las nuevas titulaciones derivadas del Espacio Europeo de EducaciónSuperior ha supuesto para las Escuelas de Ingeniería un considerable desafío, no tanto porsu contenido o metodología docente, sino por el hecho de estar enmarcados en un sistemade garantía interna de calidad que vela por la satisfacción de los grupos de interésimplicados, estudiantes incluidos. El artículo presenta los resultados y conclusiones de unaencuesta de satisfacción realizada en dos cursos consecutivos entre los estudiantes que hancursado el primer cuatrimestre de carrera y ofrece una línea de acción para la mejoracontinua deseada, especialmente en dos de las herramientas básicas de la actual educaciónsuperior: la tutoría y la mentoría para los estudiantes.; Postprint (published version)

Landing gear suspension control through adaptive backstepping techniques with H performance

Landing gear suspension control through adaptive backstepping techniques with H performance Zapateiro, Mauricio; Pozo Montero, Francesc; Rossell Garriga, Josep Maria; Karimi, Hamid Reza; Luo, Ningsu Landing gear suspension systems ful ll the tasks of absorbing the vertical energy of thetouch-down as well as providing passenger and crew comfort with a smooth ground ride beforetake-o and after landing. They are also designed to have optimal performance in the case of ahard landing. In general, the tasks of aircraft landing gears are complex and sometimes lead toa number of contradictory requirements. Although there are existing modi cations of aircraftshock absorbers to reduce the problem, the basic design conict between the requirementsfor landing and for rolling cannot be fully overcome by a passive suspension layout. Activeand semiactive suspension techniques are a solution to this problem and are capable ofreducing fuselage vibrations e ectively. In order to get satisfactory damping performancewith active and semiactive devices, appropriate control laws must be employed. In this paper,we study the use of an adaptive backstepping control with H1 performance to cope withdisturbances, uncertainties and nonlinearities, typical of suspension systems and dampingdevices. A comparison between active and semiactive strategies is provided through the analysisof simulation results.; Preprint

Design guidelines using selective harmonic elimination advanced method for DC-AC PWM with the walsh transform

Design guidelines using selective harmonic elimination advanced method for DC-AC PWM with the walsh transform Vicente Rodrigo, Jesús; Pindado Rico, Rafael; Martínez Teixidor, Inmaculada The use of the Walsh transform in DC-AC PWMwaveform generation allows the calculation of the switchingangles by means of linear equations which depend on thefundamental amplitude. However, when it is needed a wideregulation of the fundamental amplitude, conventionalapplication of Walsh transform forces to switch among differentequation sets, due to the range limitation of each one of them. Inthis paper it is described an advanced method to obtain theswitching angles that permits full regulation of the fundamentalamplitude, with only a switching interval vector, in single phasesystems. The paper shows Matlab simulation results that proofthe efficiency of the advanced method algorithm; Postprint (published version)

Experimental and numerical study of the die filling stage in powder metallurgy

Experimental and numerical study of the die filling stage in powder metallurgy Cante Terán, Juan Carlos; Oliver Olivella, Xavier; González Ferrari, Carlos; Riera Colom, María Dolores; Istúriz, Álvaro; Prado Pozuelo, José Manuel The aim of this work is to show the potential of the Particle Finite Element Method (PFEM) in the simulation of the powder transfer stage, in powder metallurgy industrial processes. The most innovative aspects of the work are: a) the intensive use of the particle finite element method technology to trace the motion of a representative set of particles in the solid and b) the solution of inherent problems associated with new meshing definition and data transfer during the calculation. Comparison of experimental results and numerical simulations are used to assess the performance of the method; Postprint (published version)

Experimental study of mass flow and apparent density in powder metallurgy die filling

Experimental study of mass flow and apparent density in powder metallurgy die filling Riera Colom, María Dolores; Istúriz, Álvaro; Prado Pozuelo, José Manuel Die filling is the first step in the process of powder compaction. The density distribution after die filling on the powder properties and the method of filling. In this work the authors study the effects of powders characteristics, size and morphology, and shoe speed on the type of mass flow during the filling and the resulting density distribution. Experimental results for different powders and die geometries are presented. Three flow regimes have been identified and their influence on apparent density is discussed; Postprint (published version)

Effect of a thermal annealing on the mechanical behaviour of green pm compacts

Effect of a thermal annealing on the mechanical behaviour of green pm compacts Riera Colom, María Dolores; Prado Pozuelo, José Manuel Cold die compaction can produce different effects on the dimensional and mechanical behaviour of green PM compacts. They can be due to different causes, such as residual stresses, microcracks and others. Residual stresses should be relieved by means of applying thermal annealing treatments. In this work, the authors present the results obtained from uniaxial compression tests applied on green specimens of an atomised iron based powder, compacted to different densities and having undergone thermal annealings at several temperatures, always below the sintering one. The stress-strain compression curves obtained are compared with those corresponding to as compacted samples. The results seem indicate the existence of residual stresses that could act at different levels: microscopically, in the contact among particles, and macroscopically, in the overall specimen resistance.; Postprint (published version)

Elastic behaviour under compressive stresses states of sintered metallic parts

Elastic behaviour under compressive stresses states of sintered metallic parts Riera Colom, María Dolores; Marbà, Isidre; Prado Pozuelo, José Manuel The mechanical response in service of a component is mainly determined by its elastic behaviour. Traditionally, metallic materials have been characterized by means of tensile tests, even in the case of sintered ones. In this condition, the elasticity of sintered parts has been always supposed to be linear, with a Young modulus dependent on the density. However, no attention has received the elastic behaviour under compressive stresses.In this work, the authors present the results obtained from cyclic uniaxial compression tests applied on sintered metallic samples with different densities. The elastic behaviour under compression is no longer linear and different mechanisms occur during the deformation process. Assuming a power law relating compressive stress and strain, an elastic modulus dependent on the density and the loading path has been obtained.; Postprint (published version)

Elastoplastic simulation of contacts among particles in granular materials

Elastoplastic simulation of contacts among particles in granular materials Riera Colom, María Dolores; Prado Pozuelo, José Manuel The mechanisms governing the densification of powdered materials under compaction are highly dependent on the deformation and the state of stress in the contact among particles. Therefore, a micromechanical model can be very useful in studying the phenomena involved in the compaction process. In this work numerical simulations showing the distributions of strain and stress in models containing two and four particles are presented. The evolution of the deformation in the contact area among particles, the residual stresses appeared after releasing the compressive load and their consequences on the macroscopic mechanical behaviour of powder compacts are here analysed; Postprint (published version)

Data generation for the numerical simulation of powder compaction

Data generation for the numerical simulation of powder compaction Prado Pozuelo, José Manuel; Riera Colom, María Dolores Numerical simulation of industrial plastic deformation processes needs of a precise characterization of the mechanical material properties included in the particular elastoplastic model. The plasticity model of bulk metallic materials is well known and the tests used for characterization are simple and well typified. The situation is quite different when the compaction of metal and ceramic powder has to be simulated; in this case, both, plasticity models and the corresponding mechanical tests are under discussion and research. Irrespective of the plastic model being employed more parameters and more complex than in the case of bulk materials must be determined. In this work the experience gained in this field by the joint effort of the research groups participating in the recently finished European Network Dienet is presented; Postprint (published version)

El barrio de Poniente en el Raval de Barcelona, 1838-1867. Un ejemplo de proyecto de vivienda masiva

El barrio de Poniente en el Raval de Barcelona, 1838-1867. Un ejemplo de proyecto de vivienda masiva Rosselló Nicolau, Maria Isabel Postprint (published version)

Optical Doppler shift with structured light

Optical Doppler shift with structured light Belmonte Molina, Aniceto; Pérez Torres, Juan When a light beam with a transverse spatially varying phase is considered for optical remote sensing, in addition tothe usual longitudinal Doppler frequency shift of the returned signal induced by the motion of the scatter along thebeam axis, a new transversal Doppler shift appears associated to the motion of the scatterer in the plane perpendicularto the beam axis. We discuss here how this new effect can be used to enhance the current capabilities of opticalmeasurement systems, adding the capacity to detect more complex movements of scatters; Postprint (published version)

El transmisor sostenible

El transmisor sostenible Gilabert Pinal, Pere Lluís; Montoro López, Gabriel; Bertran Albertí, Eduardo; Berenguer Sau, Jordi Postprint (published version)

Incorporating preferences to a multi-objective ant colony algorithm for time and space assembly line balancing

Incorporating preferences to a multi-objective ant colony algorithm for time and space assembly line balancing Chica, Manuel; Cordon, Oscar; Damas, Sergio; Pereira Gude, Jordi; Bautista Valhondo, Joaquín We present an extension of a multi-objective algorithm based on Ant Colony Optimisation to solve a more realistic variant of a classical industrial problem: Time and Space Assembly Line Balancing. We study the influence of incorporating some domain knowledge by guiding the search process of the algorithm with preferences-based dominance. Ourapproach is compared with other techniques, and every algorithm tackles a real-world instance from a Nissan plant. We prove that the embedded expert knowledge is even more justified in a real-world problem.; Postprint (published version)

A general strategy for interactive decision-making in robotic platforms

A general strategy for interactive decision-making in robotic platforms Agostini, Alejandro Gabriel; Torras, Carme; Wörgötter, Florentin This work presents an intergated strategy for planning and learning suitable to execute tasks with robotic platforms without any previous task specification. The approach rapidly learns planning operators from few action experiences using a competitive strategy where many alternatives of cause-effect explanations are evaluated in parallel, and the most successful ones are used to generate the operators. The system operates without task interruption by integrating in the planning-learning loop a human teacher that supports the planner in making decisions. All the mechanisms are integrated and synchronized in the robot using a general decision-making framework.; Preprint

Implementing a hybrid SRAM / eDRAM NUCA architecture

Implementing a hybrid SRAM / eDRAM NUCA architecture Lira Rueda, Javier; Molina, Carlos; Brooks, David; González Colás, Antonio María In this paper, we propose a hybrid cache architecture that exploits the main features of both memory technologies, speed of SRAM and high density of eDRAM. We demonstrate, that due to the high locality found in emerging applications, a high percentage of data that enters to the on-chip last-level cache are not accessed again before they are replaced; Preprint

Caracterización del proceso de valorización de la I+D universitaria

Caracterización del proceso de valorización de la I+D universitaria Berbegal Mirabent, Jasmina; Solé Parellada, Francesc El conocimiento y las tecnologías resultantes de las actividades de investigación generadas en las universidades son susceptibles de ser utilizadas en el sector empresarial, y en especial en el productivo, mediante procesos de transferencia tecnológica (TT). Precisamente estos procesos, con los años, han ido ganando cada vez más interés en la literatura sobre la gestión del conocimiento y en particular en la del conocimiento aplicado (Anderson et al., 2007), además de ir acompañados por un entusiasmo creciente por parte de las universidades, ya sea debido a presiones internas o externas (Powers y McDougall, 2005), las cuales se hanpercatado de la importancia que tienen estos procesos en el desarrollo económico de la región.Como es sabido, las universidades son importantes centros de formación pero también de investigación, lo que requiere que dispongan de canales y mecanismos para explotar los resultados tecnológicos y poderlos así aplicar al sistema productivo del entorno. Este rol de interconectividad con el entorno ha propiciado que hoy en día las universidades sean consideradas como importantes agentes dinamizadores del desarrollo local endógeno, contribuyendo al desarrollo social, cultural y económico del territorio. Aunque des de los años noventa muchas universidades empezaron a establecer políticas y a poner en marcha mecanismos para facilitar la valorización, como por ejemplo con la creación de las oficinas detransferencia de investigación (OTRI), todavía hay, en la mayoría de universidades europeas, mucho camino por recorrer. Con los organismos de transferencia se formalizó el proceso de valorización de las actividades de investigación, permitiendo a las universidades por un lado percibir rentas derivadas de la comercialización de la tecnología (Siegel et al., 2003) y por elotro, mejorar su carta de presentación, siendo mucho más atractivas tanto para estudiantes e investigadores como para empresarios.El presente trabajo se sitúa en este proceso de valorización tecnológica. En primer lugar se analiza cómo se caracteriza dicho proceso, destacando los tipos de outputs resultantes (patentes, licencias, spin-offs y contratos de investigación/consultoría). Posteriormente, mediante un meticuloso estudio bibliométrico se seleccionan aquellos artículos científicos que tratan de explicar por medio de modelos matemáticos qué indicadores sirven para explicar lasdiferencias significativas entre los distintos niveles de outputs obtenidos en un proceso. Tras su análisis, se proponen un conjunto de siete factores (ambientales, legales, capital humano estructurales, financieros, relacionales y productivos) capaces de englobar aquellos indicadores con objetivos comunes, y que sean aplicables al contexto español. Finalmente, se concluye con algunas reflexiones e implicaciones sobre el fenómeno de la valorización de laI+D universitaria así como sobre los procedimientos de recogida de datos que proporcionen este tipo de información teniendo en cuenta los indicadores y factores identificados.; Postprint (published version)

Parallel-connected legs in a grid-tied inverter system for distributed generation

Parallel-connected legs in a grid-tied inverter system for distributed generation Capellá Frau, Gabriel José; Pou Félix, Josep; Zaragoza Bertomeu, Jordi; Ceballos Recio, Salvador; Gabiola, Igor; Robles, E. Grid-connected high-power inverters are oftenused in distributed generation and power quality systems. Thoseinverters have to handle high currents in order to achieve highpower values without resorting to higher voltages. Connectinginverter legs in parallel is a proper way to achieve such highcurrents. Such parallel connection is made by means ofinductors and achieving balanced currents among the legsbecomes a critical issue. Circulating currents may produceadditional losses and stress to the converter’s power devices.Therefore, they should be controlled and minimized. Anefficient technique to achieve such balance is presented in thispaper. The proposed strategy has been developed on a gridconnectedthree-phase system. Each phase of the inverter ismade up of three legs in parallel. Besides, the controlimplemented in this work allows full regulation of the powerfactor. This way, any desired power factor value can beachieved in order to meet grid-connection requirements.Simulation and experimental results are shown in this paper.; Peer Reviewed; Postprint (published version)