Novetats

Disseny d'un joc de taula per educar i sensibilitzar envers la pobresa energètica

UPCommons - dl., 09/25/2017 - 19:56
Disseny d'un joc de taula per educar i sensibilitzar envers la pobresa energètica Vilà Miró, Roger Es dissenyarà un joc de taula educatiu dirigit a grups de adolescents entre 12 i 16 anys, que pugui ser utilitat en l'àmbit de l'educació formal (secundària) i no formal (esplais, biblioteques, caus, etc.) amb l'objectiu de sensibilitzar sobre el problema de la pobresa energètica, els actors implicats, les seves causes i possibles alternatives per a la seva gestió i solució.
Categories: Novetats

Analysis of damage in precast concrete tunnel segments during the construction phase and the influence of FRC

UPCommons - dl., 09/25/2017 - 19:52
Analysis of damage in precast concrete tunnel segments during the construction phase and the influence of FRC Suñé Pagès, Raquel The increase of the demand for tunnels is palpable. In big cities with urban density ever increasing, more and more infrastructure is competing for the limited available space, so the underground constructions have become a suitable solution. Therefore, there is a high demand for optimizing the construction processes, as well as the materials and machinery. The development of the tunnel boring machines (TBMs) had represented a significant step forward in terms of efficiency. When constructing tunnels with TBMs, the tunnel lining is built during the excavation. The precast concrete pieces that create the lining are used as a support for the TBM hydraulic jacks to push forward the machine. This interaction between the TBM and the lining can highly influence the occurring damage in the segments. The tunnel lining is one of the most important parts of the tunnel as it ensures the protection of the cavern and the stability of the tunnel, hence the quality is of paramount importance. As mentioned before, the construction phase of the tunnel is one of the most strenuous loading case for the segments. In the presented paper, two possible causes of segment damage are analysed: the uneven support of the segments when subjected to the hydraulic jack’s loading and the radial eccentricity of the hydraulic jacks. In both cases, the stress field developed is obtained through the so-called Strut-and-tie method. This method provides a simplified version of the occurring stress fields that is very useful in the calculation of D-regions where the common flexion theory is not applicable. In addition, the simplicity of the strut-and-tie models helps to provide a physical understanding of the stress fields. In Chapter 3 four cases of possible uneven supports of the segments are presented. Through the Strut-and-tie method, the stresses developed in the segment are analysed depending on the segment’s geometrical characteristics and the load applied. In Chapter 4 the effect of the radial eccentricity of the hydraulic jacks is considered. The stress field is calculated also by means of the strut-and-tie method. In both cases, the corresponding segment damages due to the two loading situations are described. Once the failure situations in Chapters 3 and 4 are described, the advantages of using fibres as a reinforcement for the segments are presented. Prior studies have shown that fibres have a positive influence in the behaviour of the hardened concrete and that they are suitable for the tunnel segments. Fibre reinforced concrete in tunnel segments may offer additional advantages over those of conventional reinforcement. In Chapter 5, the advantages of FRC segments and in particular to the type of failures described in the previous chapters are shown.
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Anàlisi experimental de la dinàmica estuariana de la Badia dels Alfacs

UPCommons - dl., 09/25/2017 - 19:49
Anàlisi experimental de la dinàmica estuariana de la Badia dels Alfacs Bagès Yáñez, Laura La Badia dels Alfacs, situada al Delta de l’Ebre, es comporta com un estuari per l’aportació d’aigua dolça que rep dels canals de desguàs provinent dels arrossars que cobreixen una gran part de la plana deltaica durant els mesos d’estiu. Així, la badia té una dinàmica molt diferenciada entre els mesos de conreu de l’arròs i de mesures ecològiques per afavorir la fauna aquàtica, en els quals els canals es troben oberts (abril-gener) i de gener a abril, en el que els canals quasi no aporten aigua dolça. Això provoca forts gradients de salinitat que afecten de manera significativa a la hidrodinàmica de la badia. A més, es tracta d’un espai de mitilicultura (especialització de l’aqüicultura en la cria del musclo) amb un valor econòmic afegit. La qualitat de l’aigua afecta de forma significativa a la producció. Aquesta està influenciada tant per la càrrega de nutrients que aporta l’aigua dolça com per la hidrodinàmica de la badia. Unes condicions de temperatures extremes o un escenari d’hipòxia poden afectar a la producció. Per entendre els processos d’oxigenació de la badia cal estudiar globalment la seva hidrodinàmica. Així, en el present treball es fa un estudi de la hidrodinàmica estuariana a partir de dades experimentals de temperatura, salinitat i oxigen dissolt del projecte MESTRAL, no només amb el fi d’entendre millor els processos que es duen a terme dins de la badia durant els mesos de canals oberts i tancats, sinó també, d’analitzar com afecten aquests en el cultiu de musclos. Es disposen de dades de cinc campanyes, realitzades al Juny del 2012, al Juliol del 2013, al Setembre del 2013, al Maig del 2014 i al Febrer del 2014. Per a l’anàlisi de les dades s’empra una base de dades oceanogràfica (Ocean Data View) i per a la presentació dels resultats, s’utilitzen dues campanyes, la del Juny 2012 per al cas de canal obert i la de Febrer 2014 per al cas de canal tancat. Els resultats mostren com durant els mesos de canals tancats les distribucions són bastant homogènies, en canvi, en la època de canals oberts es produeix una estratificació en la columna d’aigua (tant en temperatura com en salinitat i densitat) i l’aigua superficial presenta una salinitat inferior degut a l’aportació d’aigua dolça. El model de caixes mostra uns fluxos advectius importants durant els mesos d’estiu, i inferiors durant l’hivern. En canvi, el flux difusiu pren molta més importància durant els mesos de canals tancats. La distribució d’oxigen dissolt indica que es donen valors molt pròxims a la hipòxia durant els mesos de canals oberts, en canvi, durant els mesos de canals tancat els valors d’oxigen dissolt son més elevats. Tot i així, el temps de residència indica que l’aigua tarda més en renovar-se durant els mesos de canals tancats. Així, els resultats indiquen que el flux difusiu pren més importància que el temps de renovació en els processos d’oxigenació. Els baixos valors d’oxigen dissolt durant els mesos de canals obert són deguts a que, tot i que el temps de residència és inferior, les bactèries tenen una gran activitat durant aquesta època, oxidant tota la matèria orgànica (provinent dels canals i per l’excés de fitoplàncton durant els mesos d’estiu), pel que el consum d’oxigen és molt elevat. A causa de la terbolesa de l’aigua provocada per la presència de matèria orgànica, per l’estratificació en la columna d’aigua i pel poc flux difusiu vertical, les capes més profundes arriben a valors molt baixos d’oxigen dissolt.; Alfacs Bay, located in the Ebro Delta, behaves as an estuary because of the fresh water inputs from the irrigation channels of the rice fields that cover the most of the delta plain during the summer months. This causes high gradients of salinity that affect significantly the bay hydrodynamics. So, the bay has a differentiated dynamic during the months of rice crop and ecological measures addressed to favour aquatic fauna, when the channels are open (AprilJanuary) and from February to April, when channels discharge much less fresh water. Moreover, it is a place with mussel production with and economic added value. The quality of water affects significantly the production. It is influenced by the nutrients load from the fresh water and by the bay hydrodynamics. Extremes conditions of temperature or a hypoxic scenario can affect productivity. In order to understand the oxygenation processes of the bay it is necessary to study their hydrodynamics. In the present work, a study of the hydrodynamics of the bay is done from experimental data of temperature, salinity and dissolved oxygen from the MESTRAL project, not only with the objective of understanding better the processes that take place within the bay during the months of open and closed channels but also analyzing how this processes affect the mussels growing. Data from five field campaigns are available, done in June 2012, July 2013, September 2013, May 2014 and February 2014. For the data analysis an oceanographic data base is used (Ocean Data View) and for the presentation of the results, two campaigns are used, June 2012 for the open channels case and February 2014 for the closed channels case. The results show that during the months of closed channels the distributions are quite homogeneous, however, in the open channels period a stratification in the water column is produced (both for temperature and for salinity and density) and the superficial water present lower salinities because of the fresh water inputs. The box model shows an important advective flux during the summer months, and a lower during the winter. On the other hand, the diffusive flux becomes more important during the months of closed channels. The dissolved oxygen distribution indicates that values very closed to hypoxia are given during the months of open channels, but during the months of closed channels the dissolved oxygen values are higher. However, the renewal time indicates that water needs more time to remove during the months of closed channels. So, the results indicate that the diffusive flux is more important than the renewal time in the oxygenation processes. The low values of dissolved oxygen during the open channels months are due to, even that the renewal time is lower, the bacteria have a high activity during this period, oxidizing organic matter (from the channels and because of the phytoplankton exceed during the summer months), so the oxygen consumption is very high. Because of the water turbidity caused by the organic matter presence, the stratification of the water column and the low vertical diffusive flux, the lower layers of the bay present very low values of dissolved oxygen.
Categories: Novetats

Disseny d'una interfície gràfica d'un ordinador monoplaca de baix cost.

UPCommons - dv., 09/22/2017 - 18:57
Disseny d'una interfície gràfica d'un ordinador monoplaca de baix cost. González Font De Rubinat, Paula Disseny d'una interfície gràfica programada amb el llenguatge informàtic C per un ordinador monoplaca de baix cost o Raspberry Pi.
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Disseny d'un prototip de BMS per al projecte Motostudent

UPCommons - dv., 09/22/2017 - 18:49
Disseny d'un prototip de BMS per al projecte Motostudent Dorca Giro, Joan
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Estudi comparatiu de resistència lliscament longitudinal de lloses mixtes

UPCommons - dv., 09/22/2017 - 18:41
Estudi comparatiu de resistència lliscament longitudinal de lloses mixtes Esteban Pérez, Mario Descripció: Comparació de la resistència entre perfils comercials de lloses mixtes existents al mercat i perfil d'una patent creada per el Departament de Resistència de Materials de la UPC. Resultats obtinguts d'experiments realitzats al laboratori de l'escola en diferents assaigs. Adquirir les bases teòriques per extreure les conclusions pertinents.
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Pre-processing techniques for improved detection of vocalization sounds in a neonatal intensive care unit

UPCommons - dv., 09/22/2017 - 16:55
Pre-processing techniques for improved detection of vocalization sounds in a neonatal intensive care unit Raboshchuk, Ganna; Nadeu Camprubí, Climent; Vidiella Pinto, Sergio; Ros Fornells, Oriol; Muñoz Mahamud, Blanca; Riverola de Veciana, Ana The sounds occurring in the noisy acoustical environment of a Neonatal Intensive Care Unit (NICU) are thought to affect the growth and neurodevelopment of preterm infants. Automatic sound detection in a NICU is a novel and challenging problem, and it is an essential step in the investigation of how preterm infants react to auditory stimuli of the NICU environment. In this paper, we present our work on an automatic system for detection of vocalization sounds, which are extensively present in NICUs. The proposed system reduces the presence of irrelevant sounds prior to detection. Several pre-processing techniques are compared, which are based on either spectral subtraction or non-negative matrix factorization, or a combination of both. The vocalization sounds are detected from the enhanced audio signal using either generative or discriminative classification models. An audio database acquired in a real-world NICU environment is used to assess the performance of the detection system in terms of frame-level missing and false alarm rates. The inclusion of the enhancement pre-processing step leads to up to 17.54% relative improvement over the baseline.
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The Functional Impact of Alternative Splicing in Cancer

UPCommons - dv., 09/22/2017 - 16:27
The Functional Impact of Alternative Splicing in Cancer Climente-Gonzalez, Héctor; Porta-Pardo, Eduard; Godzik, Adam; Eyras, Eduardo Alternative splicing changes are frequently observed in cancer and are starting to be recognized as important signatures for tumor progression and therapy. However, their functional impact and relevance to tumorigenesis remain mostly unknown. We carried out a systematic analysis to characterize the potential functional consequences of alternative splicing changes in thousands of tumor samples. This analysis revealed that a subset of alternative splicing changes affect protein domain families that are frequently mutated in tumors and potentially disrupt protein-protein interactions in cancer-related pathways. Moreover, there was a negative correlation between the number of these alternative splicing changes in a sample and the number of somatic mutations in drivers. We propose that a subset of the alternative splicing changes observed in tumors may represent independent oncogenic processes that could be relevant to explain the functional transformations in cancer, and some of them could potentially be considered alternative splicing drivers (AS drivers).
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Uncertainty in near-surface wind speed trends at seasonal time scales

UPCommons - dv., 09/22/2017 - 16:07
Uncertainty in near-surface wind speed trends at seasonal time scales Torralba, Verónica; Torras-Reyes, Francisco J.; Gonzalez-Reviriego, Nube Observational studies have identified wind speed trends in the last decades [1,2] attributed to several factors such as changes in the land use, aerosol emissions or atmospheric circulation. However, in spite of the potential impact of this long-term variability in wind energy activities, this type of variability has not been fully characterized yet. As a consequence such information is not currently incorporated in wind power decision-making processes related to planning and management. long-term wind speed variability. For some of these users it is still difficult to identify the most suitable dataset for their specific needs, because a comparison of the quality of the wind speed data from different reanalyses at global scale is not readily available. For this reason, the present study investigates the wind speed long-term trends at global scale in the last decades (1981-2015) using three state-of-the-art reanalyses: ERA-Interim (ERA-I), the Japanese 55-year Reanalysis (JRA-55) and Modern Era Retrospective-Analysis for Research and Applications (MERRA-2).
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Level of detail for complex urban scenes with varied animated crowds, using XML

UPCommons - dv., 09/22/2017 - 15:59
Level of detail for complex urban scenes with varied animated crowds, using XML Toledo Díaz, Leonel Antonio; Rudomín, Isaac We present a system capable of handling several thousands of varied animated characters within a crowd. These characters are designed to have geometric, color animation and behaviour variety, nevertheless when a crowd becomes bigger, more memory is needed and is often difficult to achieve this objective. To solve this problem, we implemented two complementary data structures.
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Efficient data sharing on heterogeneous systems

UPCommons - dv., 09/22/2017 - 15:58
Efficient data sharing on heterogeneous systems García-Flores, Víctor; Ayguadé Parra, Eduard; Peña, Antonio J. General-purpose computing on GPUs has become more accessible due to features such as shared virtual memory and demand paging. Unfortunately it comes at a price, and that is performance. Automatic memory management is convenient but suffers from many drawbacks, preventing heterogeneous systems from achieving their full potential. In this work we analyze the challenges and inefficiencies of demand paging in GPUs, in particular on collaborative computations where data migrates multiple times between host and device. We establish that demand paging on GPUs introduces significant overheads for these kind of computations, and identify the issues of false sharing and unnecessary data transfers derived from the granularity at which data is migrated. In order to alleviate these problems we propose a memory organization and dynamic migration scheme to efficiently share data between host and device at fine granularities and without software intervention. We evaluate our design with a set of collaborative heterogeneous benchmarks and find it achieves 15% lower execution times on average with cache line-sized migrations, but severely degrading performance on benchmarks that access large blocks of contiguous memory. Page-sized migrations, although inefficient, provide on average a 47% execution time reduction with our design over a baseline system implementing demand paging. Our results suggest that cache line-sized migrations are not feasible in systems using a PCI-Express interconnect. In order to understand how future interconnect technologies will impact the feasibility of fine-grained migrations, we evaluate our scheme with various link latencies. We find interconnect latencies four to five times lower than PCI-Express are sufficient to effectively share data at finer granularities.
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Sant Medir : propostes per a una urbanització en SNU

UPCommons - dv., 09/22/2017 - 15:54
Sant Medir : propostes per a una urbanització en SNU Casas Claramunt, Ignasi Estudi de les urbanitzacions a Catalunya, centrant-se en les que estan en Sòl No Urbanitzable (SNU) i desenvolupant propostes alternatives a la situació actual, aplicables a la urbanització de Sant Medir, o Sol i Aigua, de Collserola. Aquest Projecte Final de Carrera s’ha realitzat conjuntament entre: Ignasi Casas Claramunt, Roger Maranges Bayó, i Martí Obiols Galí. Hi ha una part comuna: de les làmines 1-22 i també la darrera làmina. I cadascú entrega una part que només està a la seva entrega. Per consultar el projecte complet cal que miris les parts específiques a cada un dels co-autors les làmines 23 fins al final.
Categories: Novetats

Modelling bus contention during system early design stages

UPCommons - dv., 09/22/2017 - 15:52
Modelling bus contention during system early design stages Trilla, David; Hernandez, Carles; Abella, Jaume; Cazorla, Francisco J. Reliably upperbounding contention in multicore shared resources is of prominent importance in the early design phases of critical real-time systems to properly allocate time budgets to applications. However, during early stages applications are not yet consolidated and IP constraints may prevent sharing them across providers, challenging the estimation of contention bounds. In this paper, we propose a model to estimate the increase in applications' execution time due to on-chip bus sharing when they simultaneously execute in a multicore. The model works with information derived from the execution of each application in isolation, hence, without the need to actually run applications simultaneously. The model improves inaccuracy with respect to the existing model, and tends to over-estimate. The latter, is very important to prevent that, during late design stages, applications miss their deadline when consolidated into the same multicore, causing costly system redesign.
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LMI-based design of distributed energy-dissipation systems for vibration control of large multi-story structures

UPCommons - dj., 09/21/2017 - 19:57
LMI-based design of distributed energy-dissipation systems for vibration control of large multi-story structures Palacios Quiñonero, Francisco; Rubió Massegú, Josep; Rossell Garriga, Josep Maria; Reza Karimi, Hamid In this paper, we present an advanced computational procedure that allows obtaining distributed energy-dissipation systems for large multi-story structures. The proposed methodology is based on a decentralized velocity-feedback energy-to-componentwise-peak (ECWP) controller design approach and can be formulated as a linear matrix inequality (LMI) optimization problem with structure constraints. To demonstrate the effectiveness of the proposed design methodology, a passive damping system is computed for the seismic protection of a 20-story building equipped with a complete set of interstory viscous dampers. The high-performance characteristics of the obtained passive ECWP control system are clearly evidenced by the numerical simulation results. Also, the computational effectiveness of the proposed design procedure is confirmed by the low computation time of the associated LMI optimization problem.
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Advanced vibration control of large structures with distributed multi-actuator system and partial state information

UPCommons - dj., 09/21/2017 - 18:36
Advanced vibration control of large structures with distributed multi-actuator system and partial state information Palacios Quiñonero, Francisco; Rubió Massegú, Josep; Rossell Garriga, Josep Maria; Rodellar Benedé, José In this paper, the design and performance of partial-state controllers with incomplete multi-actuation systems for the seismic protection of tall buildings is investigated. The proposed approach considers a partially instrumented multi-story building with an incomplete system of interstory force-actuation devices implemented at selected levels of the building, and an associated set of collocated sensors that measure the interstory drifts and velocities corresponding to the instrumented stories. The main elements of the proposed controller design methodology are presented by means of a twenty-story building with two different actuation schemes. For these control configurations, partial-state controllers are designed following a static output-feedback H8 controller design approach, and the corresponding frequency and time responses are investigated. The obtained results clearly indicate that the proposed partial-state controllers are effective in mitigating the building seismic response. They also show up that a suitable distribution of the instrumented stories is a relevant factor in the control system design.
Categories: Novetats

Combinatorial structures to modeling simple games and applications

UPCommons - dj., 09/21/2017 - 17:31
Combinatorial structures to modeling simple games and applications Molinero Albareda, Xavier We connect three different topics: combinatorial structures, game theory and chemistry. In particular, we establish the bases to represent some simple games, defined as influence games, and molecules, defined from atoms, by using combinatorial structures. First, we characterize simple games as influence games using influence graphs. It let us to modeling simple games as combinatorial structures (from the viewpoint of structures or graphs). Second, we formally define molecules as combinations of atoms. It let us to modeling molecules as combinatorial structures (from the viewpoint of combinations). It is open to generate such combinatorial structures using some specific techniques as genetic algorithms, (meta-)heuristics algorithms and parallel programming, among others.
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New efficient chosen ciphertext secure Elgamal encryption schemes for secure cloud storage service

UPCommons - dj., 09/21/2017 - 17:24
New efficient chosen ciphertext secure Elgamal encryption schemes for secure cloud storage service An Wang, Xu; Ma, Jianfeng; Xhafa Xhafa, Fatos; Qin, Baodong; Zhang, Mingwu Nowadays Cloud computation has become a commonplace information service paradigm for all actors in ICT field, from individuals to big corporates. In particular, Cloud platforms and data centres are being used each time more for outsourcing data. However, data owners often worry about their data security and privacy before outsourcing the data to the Cloud, thus it is often a practice to first encrypt the data sets and then outsource them to the Cloud. The drawback of this approach is that, if the encryption scheme can only achieve chosen plaintext security, it cannot be assured to achieve strong security against many kinds of malicious adversaries in the Cloud setting. The chosen ciphertext security is essential for outsourcing ciphertexts to the Cloud, on the other hand, in most cases the data owners prefer to choose high-efficient encryption schemes for saving computation and communication costs. In this paper, we propose a new way to achieve chosen ciphertext security for Elgamal encryption scheme, which is a very basic and usual primitive for encapsulating block data encryption keys. We propose two new chosen ciphertext attack (CCA) secure schemes. The first one, which is a public key encryption proved secure in the random oracle based on the computational Diffie-Hellman (CDH) assumption, has almost no additional overhead compared with the traditional (indistinguishable under chosen plaintext attack secure Elgamal scheme, except one additional modular exponentiation for the decryption. The second scheme, which is a key encapsulation mechanism (KEM) proved secure in the standard model based on a new non-interactive assumption, has only two group elements as the encapsulations. Thus we solve the open problem left by Hanaoka et al. in Crypto'12, which consists in how to construct anindistinguishable under chosen ciphertext attack secure KEM without pairings based on a non-interactive assumption and with two group element encapsulations. To prove the scheme's security, we develop a new assumption called verifiable CDH assumption. We also generalise our technique to several existing well-known CCA secure KEMs, including the Boneh-Mei-Waters (BMW) KEM and the Hofheinz-Kiltz (HK) KEM, and show that our new schemes are even more efficient than these well-known schemes. Finally, we propose a new framework for efficient and secure data outsourcing to the Cloud based on our new schemes and present a rough analysis of its security.
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El ciclo económico y los recursos minerales. Un enfoque austriaco

UPCommons - dj., 09/21/2017 - 16:19
El ciclo económico y los recursos minerales. Un enfoque austriaco Franch Parella, Jorge Un gran avance teórico de la Escuela Austriaca, gracias a su elaborada teoría del capital, es la comprensión de los ciclos económicos. Los procesos monetarios expansivos producen graves errores de inversión que inexorablemente conducen a una recesión económica, en la que los errores se pondrán de manifiesto y surgirá la necesidad de liquidar los proyectos erróneamente emprendidos, elevando los niveles de desempleo y promoviendo la reasignación intertemporal de los recursos productivos. Uno de los sectores más perjudicados por este proceso artificial de alargamiento insostenible de la estructura productiva es la minería. Este sector es el que extrae los recursos minerales necesarios para el funcionamiento de las industrias de bienes de capital, y por ello acusa plenamente los efectos del ciclo económico, tanto en su fase alcista (sobreinversión y exceso de capacidad) como en la fase bajista (descenso del precio de mercado de las materia primas y de las ventas netas). Las variaciones de los precios de los minerales, como el níquel y la potasa, muestra un distinto comportamiento en función de cuál sea su situación dentro del conjunto de etapas de la estructura productiva. Se aplica el análisis teórico al caso de una economía avanzada con un fuerte peso del sector minero como es la australiana y se proponen algunas medidas de reforma.
Categories: Novetats

Entre un hall y cualquier otra cosa

UPCommons - dj., 09/21/2017 - 16:17
Entre un hall y cualquier otra cosa Nieto Vicente, Ramón El siguiente ensayo reúne una serie de reflexiones que tienen como origen los vestíbulos de algunos edificios civiles de Barcelona. Tras la recopilación de los más significativos de la ciudad, el primer análisis, en el que todos los seleccionados se catalogaron y ordenaron por aspectos meramente formales y tipológicos sirvió para desplegar y entender las infinitas posibilidades que estas estancias ofrecían. En esta línea, es habitual que en los libros de arquitectura los edificios aparezcan representados únicamente por sus vestíbulos, ya que son su mejor carta de presentación, sin embargo, las publicaciones se quedan en lo superficial y no profundizan en lo realmente interesante de estas piezas; la repercusión que tienen tanto en su edificio como en su contexto urbano más inmediato. Esta reflexión que se sirve de la observación y la imaginación, de detenerse durante horas a contemplar cómo las personas utilizan los halls, es la que nos permitirá configurar todo el discurso, además de establecer relaciones entre algunos de ellos que a priori parecen no tener ningún punto coincidente. La estructura definitiva del ensayo no es más que un reflejo de este proceso de estudio y análisis, ordenado cronológicamente. Se inicia con un acercamiento a la morfología y configuración de los vestíbulos, lo que nos lleva a entender su capacidad para desarrollar en ellos un sinfín de actividades, tantas que muchas de ellas se expanden más allá de los límites del propio edificio, convirtiéndose estas estancias en la escenografía civil donde se produzcan hechos urbanos concretos. En este sentido y por la manera en que las personas los habitamos, éstos pueden llegar a formar parte activa de la ciudad. La observación sobre dichos comportamientos de uso plantean que sobre un mismo soporte existan diferentes ciudades individuales que cada uno de nosotros proyectamos gracias a la imaginación y curiosidad y que existen solo en nuestro imaginario personal. Así pues, el ensayo va de lo individual, la arquitectura, a lo general, la ciudad. Para ello, el discurso se apoyará en algunas de las teorías que grandes arquitectos a lo largo de la historia han ido desarrollando. De este modo, nuestros vestíbulos objetos de estudio son un inventario de ejemplos acerca de estas reflexiones, que por otro lado, admiten tantas posibles y diferentes lecturas que se ha tomado la libertad de reinterpretarlas en muchos casos para adaptarla al contexto que nos ocupa, (el del papel que juegan los vestíbulos con respecto a la ciudad), lo que explica que las citas textuales sean una constante a lo largo de todo el texto. El resultado persigue ser un cambio en el concepto ortodoxo de ciudad utilizando el vestíbulo como argumento, y que desemboque en el entendimiento de sus infinitas lecturas, por ejemplo las posibilidades de expansión de ésta sin necesidad de su crecimiento físico, la atención en los detalles casuales que ofrece, el uso personal que cada uno de nosotros hacemos de ella o cualquier otra cosa.
Categories: Novetats

Predictability of extreme intensity pulses in optically injected semiconductor lasers

UPCommons - dj., 09/21/2017 - 16:12
Predictability of extreme intensity pulses in optically injected semiconductor lasers Martinez Alvarez, Nuria; Borkar, Saurabh; Masoller Alonso, Cristina The predictability of extreme intensity pulses emitted by an optically injected semiconductor laser is studied numerically, by using a well-known rate equation model. We show that symbolic ordinal time-series analysis allows to identify the patterns of intensity oscillations that are likely to occur before an extreme pulse. The method also gives information about patterns which are unlikely to occur before an extreme pulse. The specific patterns identified capture the topology of the underlying chaotic attractor and depend on the model parameters. The methodology proposed here can be useful for analyzing data recorded from other complex systems that generate extreme fluctuations in their output signals. This is a copy of the author 's final draft version of an article published in the journal European physical journal. Special topics.
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