Showing papers by "Polytechnic University of Catalonia published in 2022"
TL;DR: In this article, a semi-structured questionnaire was designed to assess how the COVID-19 lockdown affects Chinese consumers' purchasing and consumption behavior from a sustainability point of view.
46 citations
TL;DR: In this article, the one-step synthesis of new tailored nanoporous carbons from the common polypody (Polypodium vulgare) as feedstock for the first time was presented.
31 citations
TL;DR: In this article, biomass-derived carbons with adequate textural properties were synthesized via agarose double-step pyrolysis followed by steam activation for H2O2 production.
26 citations
TL;DR: A new sensorless scheme that accurately observe the rotor angle at low speeds, including standstill condition, without injecting high frequency signals is presented.
Abstract: Position estimation at low/zero speed for permanent magnet synchronous machines is commonly achieved with the injection of high-frequency signals. This article presents a new sensorless scheme that accurately observe the rotor angle at low speeds, including standstill condition, without injecting high-frequency signals. The algorithm is built upon a previous sliding-mode current controller and uses the switching functions slopes inaccuracies produced by the saliency effect to determine the rotor position and speed. Thanks to the equivalent control concept and together with a sliding-mode-based phase-locked loop observer defined by a complex switching function, the algorithm provides both rotor position and speed in a compact form. This article includes the main working principle and defines the operational range of the proposed scheme. Finally, the feasibility of the method is corroborated through experimental results in sensorless configuration.
19 citations
TL;DR: In this paper , a simple strategy to modify the oxygen-based groups of graphene oxide using hydrochloric acid treatment, which boosts the electric output based on the device structure of GO/PVA MEGs, was reported.
18 citations
01 Jan 2022
18 citations
TL;DR: In this paper, a deep learning approach was proposed for black-box modeling of step-down converters used in more electric aircrafts, which can be applied to many power devices, including diverse types of power converters, power supplies or filters among others.
Abstract: This article presents a novel approach for black-box modeling of 270 V-to-28 V dc–dc step-down converters used in more electric aircrafts. These converters normally feed constant power loads. The proposed deep learning approach, uses offline experimental data of the converter to find an accurate model that reproduces its behavior. It covers a broad range of loading conditions to build a model that replicates the whole behavior of the converter. This article compares the performance of the proposed method, which requires a very low computational burden once the model is trained, with that of a conventional recurrent neural network topology. Results presented in this article show the ability of the obtained solution to accurately emulate the behavior of the real step-down converter when the internal structure is unknown, with no knowledge of the internal parameters, thus preventing disclosure of manufacturer's confidential data. The modeling strategy presented in this article is validated with experimental data by using a step-down converter used in aircrafts. The approach is compared to existing modeling techniques to test its accuracy. This approach can also be applied to many power devices, including diverse types of power converters, power supplies, or filters among others.
17 citations
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TL;DR: This article aims to modify the EPLL structure to improve its stability margin, and at the same time, make it unconditionally stable in the positive parameter space from a small-signal point of view.
Abstract: The enhanced phase-locked loop (EPLL) is one of the most famous PLLs in single-phase applications and a versatile tool for different signal processing applications, especially for the grid synchronization of power converters. Recently, it has been proved that the EPLL has a quite narrow stable zone (compared to its unstable zone) in the positive parameter space from a small-signal point of view. This zone will be even more narrow if maintaining a minimum stability margin is required. This article aims to modify the EPLL structure to improve its stability margin, and at the same time, make it unconditionally stable in the positive parameter space from a small-signal point of view.
16 citations
TL;DR: In this paper, a cascade model-predictive control for a three-phase unity power factor rectifier is presented, where the output power is used as a feedforward to enhance the transient dynamics of the output dc voltage.
Abstract: In this article, a novel cascade model-predictive control for a three-phase unity power factor rectifier is presented. Unlike the traditional control techniques for rectifiers, the proposed method uses a cascade dual-model-predictive control for the inner and outer control loops. The three-phase currents of the rectifier are controlled with the inner control loop, while the desired output voltage is achieved with the outer control loop. In this proposal, the output power is used as a feedforward to enhance the transient dynamics of the output dc voltage. Several advantages can be highlighted such as a fixed switching frequency, and output voltage variations are avoided when a sudden change in the load or a voltage sag appears. The overall control proposal has been fully integrated into a digital signal processor. Selected experimental results are introduced to validate the theoretical contributions of this article.
16 citations
TL;DR: In this paper, the performance of a gas sensor array for detecting smouldering and plastic fires while ensuring the rejection of a set of nuisances was evaluated using PLS-DA and SVM.
Abstract: Smouldering fires are characterized by the production of early gas emissions that can include high levels of CO and Volatile Organic Compounds (VOCs) due to pyrolysis or thermal degradation. Nowadays, standalone CO sensors, smoke detectors, or a combination of these, are standard components for fire alarm systems. While gas sensor arrays together with pattern recognition techniques are a valuable alternative for early fire detection, in practice they have certain drawbacks—they can detect early gas emissions, but can show low immunity to nuisances, and sensor time drift can render calibration models obsolete. In this work, we explore the performance of a gas sensor array for detecting smouldering and plastic fires while ensuring the rejection of a set of nuisances. We conducted variety of fire and nuisance experiments in a validated standard fire room (240 m3). Using PLS-DA and SVM, we evaluate the performance of different multivariate calibration models for this dataset. We show that calibration models remain predictive after several months, but perfect performance is not achieved. For example, 4 months after calibration, a PLS-DA model provides 100% specificity and 85% sensitivity since the system has difficulties in detecting plastic fires, whose signatures are close to nuisance scenarios. Nevertheless, our results show that systems based on gas sensor arrays are able to provide faster fire alarm response than conventional smoke-based fire alarms. We also propose the use of small-scale fire experiments to increase the number of calibration conditions at a reduced cost. Our results show that this is an effective way to increase the performance of the model, even when evaluated on a standard fire room. Finally, the acquired datasets are made publicly available to the community.
15 citations
TL;DR: This paper provides a thorough analysis of the influence of using the different SUMO’s traffic demand generation tools on mobility and node connectivity and proposes an automatized tool that facilitates researchers the generation of synthetic traffic based on real data.
TL;DR: In this article , a new biobased epoxy, derived from poly(limonene carbonate) oxide (PLCO), was combined with polyetheramine and polyamineamide curing agents, offering a spectrum of thermal and mechanical properties, superior to DGEBA-based thermosets.
Abstract: In the area of coating development, it is extremely difficult to find a substitute for bisphenol A diglycidyl ether (DGEBA), the classical petroleum-based raw material used for the formulation of epoxy thermosets. This epoxy resin offers fast curing reaction with several hardeners and the best thermal and chemical resistance properties for applications in coatings and adhesive technologies. In this work, a new biobased epoxy, derived from poly(limonene carbonate) oxide (PLCO), was combined with polyetheramine and polyamineamide curing agents, offering a spectrum of thermal and mechanical properties, superior to DGEBA-based thermosets. The best formulation was found to be a combination of PLCO and a commercial curing agent (Jeffamine) in a stoichiometric 1:1 ratio. Although PLCO is a solid due to its high molecular weight, it was possible to create a two-component partially biobased epoxy paint without the need of volatile organic compounds (i.e., solvent-free formulation), intended for use in coating technology to partially replace DGEBA-based thermosets.
TL;DR: In this paper, 3D-printed ceria structures have been prepared by robocasting, without using any additive, and impregnated with different amounts of Ni and Ru, characterized and tested for the catalytic decomposition of ammonia in a fixed bed reactor.
TL;DR: Evaluating the performance of a solar thermal microalgal biomass pre-treatment prior to the anaerobic co-digestion with raw sewage showed a positive energy balance, as the total energy produced was twice the energy consumed in the system.
TL;DR: The authors of as mentioned in this paper acknowledge CARNET-The Future Mobility Research HUB to allow the usage and work on the BCN-VML network, as well as PTV VISUM for the traffic software license.
TL;DR: In this article, a combination of the Finite Element Method (FEM), the Particle Finite Elements Method (PFEM), and the Discrete Element Method(DEM) for modeling and analyzing the failure of reinforced concrete structures under impulsive wave forces originating from free-surface flows in critical water hazards is presented.
TL;DR: In this paper, the authors report the automated deployment of 5G services, in particular, a public safety video surveillance use case employing low-latency object detection and tracking using on-camera and on-edge analytics.
Abstract: The H2020 METRO-HAUL European project has architected a latency-aware, cost-effective, agile, and programmable optical metro network. This includes the design of semidisaggregated metro nodes with compute and storage capabilities, which interface effectively with both 5G access and multi-Tbit/s elastic optical networks in the core. In this paper, we report the automated deployment of 5G services, in particular, a public safety video surveillance use case employing low-latency object detection and tracking using on-camera and on-the-edge analytics. The demonstration features flexible deployment of network slice instances, implemented in terms of European Telecommunications Standards Institute (ETSI) network function virtualization network services. We summarize the key findings in a detailed analysis of end-to-end quality of service, service setup time, and soft-failure detection time. The results show that the round-trip time over an 80 km link is under 800 µs and the service deployment time is under 180 s.
01 Jan 2022
TL;DR: In this paper, a continuous-time evolutionary game dynamics for generalized Nash equilibrium seeking in equality-constrained population games is proposed, and sufficient conditions to guarantee the asymptotic stability, nonemptiness, compactness, and optimality of the proposed dynamics for certain population games are provided.
Abstract: This letter proposes a novel form of continuous-time evolutionary game dynamics for generalized Nash equilibrium seeking in equality-constrained population games. Using Lyapunov stability theory and duality theory, we provide sufficient conditions to guarantee the asymptotic stability, non-emptiness, compactness, and optimality of the equilibria set of the proposed dynamics for certain population games. Moreover, we illustrate our theoretical developments through a numerical simulation of an equality-constrained congestion game.
TL;DR: In this article , the effectiveness, efficiency, and feasibility of any city establishing a smart public lighting infrastructure network are discussed, together with a holistic analysis based on the Value Creation Ecosystem (VCE) and the City Model Canvas (CMC) to visualise how such plans may offer public value with a long-term and sustainable approach.
TL;DR: In this article, the authors acknowledge the support from the European Union Horizon 2020 Research and Innovation Programme under the grant agreements No 691735 and No 681735, respectively, with the support of the Serra Hunter program.
Polytechnic University of Catalonia1, Institut Català de Ciències del Clima2, Institute of Marine Sciences3, Argans (United Kingdom)4, European Space Agency5, Remote Sensing Center6, Naval Postgraduate School7, Nankai University8, Comisión Sectorial de Investigación Científica9, University of Oviedo10
TL;DR: Martínez et al. as discussed by the authors presented the methodologies used to produce the new enhanced Arctic SMOS SSS product, which consists of 9 d averaged maps in an EASE 2.0 grid of 25 km.
Abstract: Abstract. Measuring salinity from space is challenging since the sensitivity of the brightness temperature (TB) to sea surface salinity (SSS) is low (about 0.5 K psu−1), while the SSS range in the open ocean is narrow (about 5 psu, if river discharge areas are not considered). This translates into a high accuracy requirement of the radiometer (about 2–3 K). Moreover, the sensitivity of the TB to SSS at cold waters is even lower (0.3 K psu−1), making the retrieval of the SSS in the cold waters even more challenging. Due to this limitation, the ESA launched a specific initiative in 2019, the Arctic+Salinity project (AO/1-9158/18/I-BG), to produce an enhanced Arctic SSS product with better quality and resolution than the available products. This paper presents the methodologies used to produce the new enhanced Arctic SMOS SSS product (Martínez et al., 2019) . The product consists of 9 d averaged maps in an EASE 2.0 grid of 25 km. The product is freely distributed from the Barcelona Expert Center (BEC, http://bec.icm.csic.es/, last access: 25 January 2022) with the DOI number https://doi.org/10.20350/digitalCSIC/12620 (Martínez et al., 2019). The major change in this new product is its improvement of the effective spatial resolution that permits better monitoring of the mesoscale structures (larger than 50 km), which benefits the river discharge monitoring.
TL;DR: In this article, three innovative methods (encapsulation, nanoparticulation, and chelation) were explored, which aim to overcome problems associated with conventional fortification, especially those affecting organoleptic properties and bioavailability; but often lead to the emergence of new limitations (for example instability, impracticality and high costs) requiring further research.
TL;DR: In this article , the authors used the Integrated Value Model for Sustainability Assessment (MIVES) model to assess the sustainability performance of fiber cement boards for facade cladding, which can be used for assessing facade-cladding techniques made of any material and for any type of building.
TL;DR: In this article, the authors focus on assessing the environmental performance of European ports based on a wide representation of EcoPorts members, using the Self-Diagnosis Method (SDM), a concise checklist against which port managers can self-assess the environmental management of their port in relation to the performance of the membership.
TL;DR: A new isometric strain model is introduced for the study of the dynamics of cloth garments in a moderate stress environment, such as robotic manipulation in the neighborhood of humans, which results in an accurate, when compared to the recorded dynamics of real textiles, description of cloth motion incorporating aerodynamic effects.
TL;DR: In this paper, the authors investigated the processes controlling the origin and distribution of recharge and groundwater composition in the Andean Precordillera and Altiplano of the Tarapaca Region of northern Chile, using major solutes in spring, river and well water, and the stable and radioactive isotopes of water oxygen, hydrogen, and dissolved inorganic carbon.
TL;DR: In this article , an adaptive, flexible, expandable, simple, and high-accuracy methodology capable of maximizing vehicle range with the finest computational effort, thanks to a genetic algorithm, is described.
TL;DR: In this paper, the authors introduce the intent-based networking (IBN) paradigm and its application to optical networking, highlighting the benefits that machine learning (ML) algorithms can provide to IBN.
Abstract: The intent-based networking (IBN) paradigm targets defining high-level abstractions so network operators can define what their desired outcomes are without specifying how they would be achieved. The latter can be achieved by leveraging network programmability, monitoring, and data analytics, as well as the key assurance component. In this tutorial, we introduce the IBN paradigm and its application to optical networking, highlighting the benefits that machine learning (ML) algorithms can provide to IBN. Because the deployment of ML applications requires a specific orchestrator to create ML functions that are connected as ML pipelines, we show an implementation of such an orchestrator. Some challenges and solutions are presented for the generation of accurate synthetic data, proactive self-configuration, and cooperative intent operation. Illustrative examples of intent-based operation and numerical results are presented, and the obtained performance is discussed.
TL;DR: In this paper , the authors evaluated the effect of nZVI pulses on the removal of NO3- from groundwater in packed soil columns and, more particularly, to elucidate whether or not biotic NO3 removal processes were promoted by NZVI.
TL;DR: In this paper, the authors developed a novel co-simulation to leverage the transient flow exchange between crops and buildings by incorporating the plant's heat and mass balances in building simulation.