Novetats

Vida interestelar

UPCommons - dc., 03/20/2019 - 19:36
Vida interestelar Barceló Garcia, Miquel
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Hacia el centro galáctico

UPCommons - dc., 03/20/2019 - 19:13
Hacia el centro galáctico Barceló Garcia, Miquel
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La nave espacial Tierra

UPCommons - dc., 03/20/2019 - 19:04
La nave espacial Tierra Barceló Garcia, Miquel
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Dios en el futuro del universo

UPCommons - dc., 03/20/2019 - 18:34
Dios en el futuro del universo Barceló Garcia, Miquel
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Numerical and experimental study of initiation and propagation of desiccation cracks in clayey soils

UPCommons - dc., 03/20/2019 - 18:32
Numerical and experimental study of initiation and propagation of desiccation cracks in clayey soils Levatti, Hector Ulises; Prat Catalán, Pere; Ledesma Villalba, Alberto This paper presents the fundamentals and the mathematical formulation to study desiccation cracking in soils based on Unsaturated Soil Mechanics as well as a numerical analysis of a previous desiccation test program. The numerical approach implemented in MATLAB is used in 2D simulations on radial sections of the cylindrical specimens and in a theoretical study of the stress field in plane strain conditions. The numerical analysis, based on two stress stare variables (total net stress and suction) is consistent and in good agreement with the experimental results, including the location of cracks and time of crack initiation.
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Embroidery textile moisture sensor

UPCommons - dc., 03/20/2019 - 18:07
Embroidery textile moisture sensor Martínez Estrada, Marc; Moradi, Bahareh; Fernández García, Raúl; Gil Galí, Ignacio
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Force-based representation for non-rigid shape and elastic model estimation

UPCommons - dc., 03/20/2019 - 17:50
Force-based representation for non-rigid shape and elastic model estimation Agudo Martínez, Antonio; Moreno-Noguer, Francesc IEEE This paper addresses the problem of simultaneously recovering 3D shape, pose and the elastic model of a deformable object from only 2D point tracks in a monocular video. This is a severely under-constrained problem that has been typically addressed by enforcing the shape or the point trajectories to lie on low-rank dimensional spaces. We show that formulating the problem in terms of a low-rank force space that induces the deformation and introducing the elastic model as an additional unknown, allows for a better physical interpretation of the resulting priors and a more accurate representation of the actual object's behavior. In order to simultaneously estimate force, pose, and the elastic model of the object we use an expectation maximization strategy, where each of these parameters are successively learned by partial M-steps. Once the elastic model is learned, it can be transfered to similar objects to code its 3D deformation. Moreover, our approach can robustly deal with missing data, and encode both rigid and non-rigid points under the same formalism. We thoroughly validate the approach on Mocap and real sequences, showing more accurate 3D reconstructions than state-of-the-art, and additionally providing an estimate of the full elastic model with no a priori information. © 20xx 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.
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Random planar maps and graphs with minimum degree two and three

UPCommons - dc., 03/20/2019 - 17:35
Random planar maps and graphs with minimum degree two and three Noy Serrano, Marcos; Ramos, Lander We find precise asymptotic estimates for the number of planar maps and graphs with a condition on the minimum degree, and properties of random graphs from these classes. In particular we show that the size of the largest tree attached to the core of a random planar graph is of order c log(n) for an explicit constant c. These results provide new information on the structure of random planar graphs.
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Relación entre la factor de comportamiento y la demanda de ductilidad en función de distintas características sísmicas

UPCommons - dc., 03/20/2019 - 17:05
Relación entre la factor de comportamiento y la demanda de ductilidad en función de distintas características sísmicas Figueras Pelijero, Gerard Design standards allows designing for reduced seismic force in terms of behaviour ductility factor, which is tabulated in codes for different structural systems. However, its values differ significantly in different countries. Although failure can be avoided, damage can be significant and difficult to control with the standard procedure. This research will investigate the effects of different behaviour factors on the ductility demand, which is representative of the expected damage, for different types of earthquakes, hysteresis shapes and systems.
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Model error for rotation capacity of reinforced concrete plastic hinges for performance-based design

UPCommons - dc., 03/20/2019 - 16:53
Model error for rotation capacity of reinforced concrete plastic hinges for performance-based design Garcia Villa, Otto The thesis will assess the error in ductility demand estimated through the double-linear-analysis method for seismic design when compared against non-linear time-history analysis. A representative set of irregular structures will be considered for design and assessment. The statistics of the error of the model will be determined. Finally, a suitable safety factor will be calibrated for target reliability factor.
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Guia temàtica Biblioteca ETSAB: Bauhaus 1919-2019

UPCommons - dt., 03/19/2019 - 20:19
Guia temàtica Biblioteca ETSAB: Bauhaus 1919-2019 Escola Tècnica Superior d'Arquitectura de Barcelona. Biblioteca Bibliografia amb una selecció de documents (llibres, revistes, audiovisuals, etc.) exposats a la Biblioteca Oriol Bohigas ETSAB durant els mesos de març - maig del 2019, coincindint amb la celebració del centenari de la Bauhaus.
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An NFV-based energy scheduling algorithm for a 5G enabled fleet of programmable unmanned aerial vehicles

UPCommons - dt., 03/19/2019 - 19:52
An NFV-based energy scheduling algorithm for a 5G enabled fleet of programmable unmanned aerial vehicles Tipantuña, Christian; Hesselbach Serra, Xavier; Sánchez Aguero, Víctor; Valera Pintor, Francisco; Vidal Fernández, Iván; Nogales Dorado, Borja The fifth generation of mobile networks (5G) is expected to provide diverse and stringent improvements such as greater connectivity, bandwidth, throughput, availability, improved coverage, and lower latency. Considering this, drones or Unmanned Aerial Vehicles (UAVs) and Internet of Things (IoT) devices are perfect examples of existing technology that can take advantage of the capabilities provided by 5G technology. In particular, UAVs are expected to be an important component of 5G networks implementations and support different communication requirements and applications. UAVs working together with 5G can potentially facilitate the deployment of standalone or complementary communications infrastructures, and, due to its rapid deployment, these solutions are suitable candidates to provide network services in emergency scenarios, natural disasters, and search and rescue missions. An important consideration in the deployment of a programmable drone fleet is to guarantee the reliability and performance of the services through consistent monitoring, control, and management scheme. In this regard, the Network Functions Virtualization (NFV) paradigm, a key technology within the 5G ecosystem, can be used to perform automation, management, and orchestration tasks. In addition, to ensure the coordination and reliability in the communications systems, considering that the UAVs have a finite lifetime and that eventually they must be replaced, a scheduling scheme is needed to guarantee the availability of services and efficient resource utilization. To this end, in this paper is presented an UAV scheduling scheme which leverages the potential offered by NFV. The proposed strategy, based on a brute-force search combinatorial algorithm, allows obtaining the optimal scheduling of UAVs in time, in order to efficiently deploy network services. Simulation results validate the performance of the proposed strategy, by providing the number of drones needed to meet certain levels of service availability. Furthermore, the strategy allows knowing the sequence of replacement of UAVs to ensure the optimal resource utilization.
Categories: Novetats

Usefulness of bioelectrical impedance analysis for monitoring patients with refractory ascites

UPCommons - dt., 03/19/2019 - 19:21
Usefulness of bioelectrical impedance analysis for monitoring patients with refractory ascites Ontanilla Clavijo, Guillermo; Ampuero Herrojo, Javier; Borreguero, Samuel; Rosell Ferrer, Francisco Javier; Romero Gómez, Manuel Background: bioelectrical impedance analysis is a technique for the determination of the hydropic component. The hydropic component, determined by blood volume, could be a reflection of the hemodynamic situation. This study aimed to evaluate the usefulness of peripheral bioelectrical impedance analysis (BIA) for the prediction of hemodynamic changes in large-volume paracentesis and prognosis. Methods: this was a proof-of-concept prospective study of 14 patients with liver cirrhosis and refractory ascites. Peripheral bioimpedance was measured three times using a portable device, IVOL®, before and after large-volume paracentesis, at different frequencies (5, 10, 20, 50, 100 and 200 kHz). Consequently, resistance, reactance and phase angle were obtained, both pre- and post-paracentesis (the difference between them was defined as ¿). Results: the mean age of patients was 62.2 ± 9.6 years, the Child-Pugh was 8.4 ± 1.3 and the MELD score was 15.2 ± 3.9. A direct correlation between the extraction of ascitic fluid and ¿resistance (10 kHz [r = 0.722; n = 12; p = 0.008], 20 kHz [r = 0.658; n = 12; p = 0.020] and 50 kHz [r = 0.519; n = 14; p = 0.057]) was observed. The presence of edema was related to lower values of both pre-paracentesis resistance (10 Hz [23.9 ± 8 vs 32.2 ± 4; p = 0.043]) and phase angle (5 kHz [-1.9 ± 2.8 vs 5.9 ± 7.3; p = 0.032]). Pre-paracentesis phase angle was directly correlated with the decline in blood pressure after paracentesis at lower frequencies (5 kHz [r = 0.694; n = 13; p = 0.008] and 10 kHz [r = 0.661; n = 13; p = 0.014]). Lower frequencies of ¿phase-angle impacted on patient prognosis (5 kHz [-8.6 ± 5 vs -2.5 ± 2.7; p = 0.021]), patients with ¿phase-angle 5 kHz > -4 had a higher rate of mortality (83.3% [5/6] vs 0% [0/6]; logRank 7.306, p = 0.007). ¿resistance values were associated with overt HE at six months (10 kHz [4.9 ± 2.5 vs -0.4 ± 4.7; p = 0.046]). Conclusions: in conclusion, a significant correlation between peripheral impedance and hemodynamic changes was found. Impedance was also significantly related to prognosis and overt hepatic encephalopathy.
Categories: Novetats

Use of low smoke and halogen free cables for marine fire safety design

UPCommons - dt., 03/19/2019 - 19:13
Use of low smoke and halogen free cables for marine fire safety design Casals Torrens, Pau; Castells Sanabra, Marcel·la Safety of shipping is a growing concern. The causes of shipping casualties are various. A fire on a ship is one of the most hazardous incidents which can happen on board and a common cause of damages and accidents in ships. However, this knowledge decreases where electrical installations, whose effects are less well-understood, are involved. Because of these effects and risks, the regulations related to cables for a vessel’s electrical installations anticipate the use of special low fire propagation and fire-resistant cables made with low smoke emission and halogen-free materials. Despite these criteria, the regulations permit the use of materials such as PVC. The main purpose of this research is to identify the risks associated of the use of PVC versus Low Smoke Zero Halogen (LSOH) cables that could be present for equipment safety and people in case of fire. As a result of the implementation of the regulatory framework, test results from PVC and LSOH cables used in ships have beenobtained. Finally, the use of LSOH cables is implemented to assess the effect of fire risk reduction measure for the enhancement of safety of shipping in coastal waters, efficiency and protection of the environment.
Categories: Novetats

Advanced methodology for the optimal sizing of the energy storage system in a hybrid electric refuse collector vehicle using real routes

UPCommons - dt., 03/19/2019 - 19:03
Advanced methodology for the optimal sizing of the energy storage system in a hybrid electric refuse collector vehicle using real routes Cortez, Ernest; Moreno Eguilaz, Juan Manuel; Soriano Alfonso, Franciso This paper presents a new methodology for optimal sizing of the energy storage system ( ESS ), with the aim of being used in the design process of a hybrid electric (HE) refuse collector vehicle ( RCV ). This methodology has, as the main element, to model a multi-objective optimisation problem that considers the specific energy of a basic cell of lithium polymer ( Li – Po ) battery and the cost of manufacture. Furthermore, optimal space solutions are determined from a multi-objective genetic algorithm that considers linear inequalities and limits in the decision variables. Subsequently, it is proposed to employ optimal space solutions for sizing the energy storage system, based on the energy required by the drive cycle of a conventional refuse collector vehicle. In addition, it is proposed to discard elements of optimal space solutions for sizing the energy storage system so as to achieve the highest fuel economy in the hybrid electric refuse collector vehicle design phase.
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Inkjet-printed, functional heterolayers of ZnO@CuO for stoma pouch monitoring

UPCommons - dt., 03/19/2019 - 18:56
Inkjet-printed, functional heterolayers of ZnO@CuO for stoma pouch monitoring Ortiz Perez, A.; Gao, H.; Lyu, X.; Wöllenstein, Jürgen; Kallfaß, V; Fonollosa Magrinyà, Jordi; Palzer, S. Many bowel cancer patients are in need of an artificial stoma as part of their surgical treatment, and associated post-surgical odours caused by leaking stoma pouches may lead to social isolation, which is why inconspicuous monitoring of this situation is important for affected persons. The integration of micro- and nanotechnology may offer low-cost, low-power consumption and small solutions to this challenge. To this end, we present an inkjet-printed, heterostructured gas sensor that has been built by incorporating nanosized p-type semiconducting CuO in a porous n-type ZnO matrix. The functional layer is fabricated using a combination of a colloidal suspension and sol–gel approach optimized for inkjet printing thus offering an industry-ready method for integration of nanomaterials in microelectromechanical systems (MEMS) structures. Using a thermal modulation scheme we enhance the information content and classify different events. We demonstrate that a simple MEMS device using a novel hetero-nanomaterial may be used to reliably identify situations where stoma pouch content escapes. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
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Environment-friendly marine transportation following the international regulation changes

UPCommons - dt., 03/19/2019 - 18:51
Environment-friendly marine transportation following the international regulation changes Rodrigo de Larrucea, Jaime Principales regulaciones OMI en medio ambiente marino: MARPOL; Convenio Aguas de lastre; Convenio reciclaje de buques y de remoción de restos; etc Comunicación presentada en KOREA INTERNATIONAL COOPERATION CONFERENCE ON OCEAN AND FISHERIES KICCOF-Nairobi 2018
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Impact of conductive yarns on an embroidery textile moisture sensor

UPCommons - dt., 03/19/2019 - 18:46
Impact of conductive yarns on an embroidery textile moisture sensor Martínez Estrada, Marc; Moradi, Bahareh; Fernández García, Raúl; Gil Galí, Ignacio In this work, two embroidered textile moisture sensors are characterized with three different conductive yarns. The sensors are based on a capacitive interdigitated structure embroidered on a cotton substrate with an embroidered conductor yarn. The performance comparison of three different type of conductive yarns has been addressed. In order to evaluate the sensor sensitivity, the impedance of the sensor has been measured by means of an LCR meter from 20 Hz to 20 kHz on a climatic chamber with a sweep of the relative humidity from 30% to 65% at 20 ¿C. The experimental results show a clear and controllable dependence of the sensor impedance with the relative humidity and the chosen conductor yarns. This dependence points out the optimum conductive yarn to be used to develop wearable applications for moisture measurement
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A Simple Closed-Loop Active Gate Voltage Driver for Controlling diC/dt and dvCE/dt in IGBTs

UPCommons - dt., 03/19/2019 - 18:36
A Simple Closed-Loop Active Gate Voltage Driver for Controlling diC/dt and dvCE/dt in IGBTs Ghorbani, Hamidreza; Sala Caselles, Vicenç; Paredes Camacho, Alejandro; Romeral Martínez, José Luis The increase of the switching speed in power semiconductors leads to converters with better efficiency and high power density. On the other hand, fast switching generates some consequences like overshoots and higher switching transient, which provoke electromagnetic interference (EMI). This paper proposes a new closed-loop gate driver to improve switching trajectory in insulated gate bipolar transistors (IGBTs) at the hard switching condition. The proposed closed-loop gate driver is based on an active gate voltage control method, which deals with emitter voltage (VEe) for controlling diC/dt and gets feedback from the output voltage (vCE) in order to control dvCE/dt. The sampled voltage signals modify the profile of the applied gate voltage (vgg). As a result, the desired gate driver (GD) improves the switching transients with minimum switching loss. The operation principle and implementation of the controller in the GD are thoroughly described. It can be observed that the new GD controls both dvCE/dt and diC/dt accurately independent of the variable parameters. The new control method is verified by experimental results. As a current issue, the known trade-off between switching losses and EMI is improved by this simple and effective control method.
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Pla de detall de la conversa distesa entre el Rector Antoni Giró i dos homes més mentre esperen l'arribada d'autoritats polítiques per l'acte de nomenament i investidura del Prof. Manuel Ramón Llamas com a Doctor Honoris Causa

UPCommons - dt., 03/19/2019 - 16:31
Pla de detall de la conversa distesa entre el Rector Antoni Giró i dos homes més mentre esperen l'arribada d'autoritats polítiques per l'acte de nomenament i investidura del Prof. Manuel Ramón Llamas com a Doctor Honoris Causa Pareto, Jordi
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