Ekaitz Zulueta

Ekaitz Zulueta
Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Systems and Automatic Engineering

About

152
Publications
52,486
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1,288
Citations
Citations since 2017
79 Research Items
983 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250

Publications

Publications (152)
Article
Full-text available
The application of computational fluid dynamics (CFD) to turbulent flow has been a considerable topic of research for many years. Nonetheless, using CFD tools results in a large computational cost, which implies that, for some applications, CFD may be unviable. To date, several authors have carried out research applying deep learning (DL) technique...
Article
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The Deep Deterministic Policy Gradient (DDPG) algorithm is a reinforcement learning algorithm that combines Q-learning with a policy. Nevertheless, this algorithm generates failures that are not well understood. Rather than looking for those errors, this study presents a way to evaluate the suitability of the results obtained. Using the purpose of...
Article
Full-text available
Solid-state batteries represent a promising technology in the field of high-energy-density and safe storage systems. Improving the understanding of how defects form within these cells would greatly facilitate future development, which would be best served by applying nondestructive analytical tools capable of characterization of the key components...
Article
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This paper introduces the use of a new low-computation cost algorithm combining neural networks with the Nelder–Mead simplex method to monitor the variations of the parameters of a previously selected equivalent circuit calculated from Electrochemical Impedance Spectroscopy (EIS) corresponding to a series of battery aging experiments. These variati...
Article
Full-text available
When training a feedforward stochastic gradient descendent trained neural network, there is a possibility of not learning a batch of patterns correctly that causes the network to fail in the predictions in the areas adjacent to those patterns. This problem has usually been resolved by directly adding more complexity to the network, normally by incr...
Article
This article presents a method for selecting the best battery sizing based on an optimal market participation strategy in a hybrid renewable power plant. The proposed formulation considers different scenarios to ensure the reserve provision compliance and includes two terms. The first one maximizes the day-ahead and automatic frequency restoration...
Article
In recent decades, traditional energy generation and consumption have undergone a transformation to cleaner energy sources. The transition to a sustainable energy system based on efficiency and renewable energies will thus require the replacement of a complex and heavily implemented energy system with one based on concepts such as microgrids. A mic...
Article
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Nowadays everyone should be aware of the importance of reducing CO2 emissions which produce the greenhouse effect. In the field of construction, several options are proposed to reach nearly-Zero Energy Building (nZEB) standards. Obviously, before undertaking a modification in any part of a building focused on improving the energy performance, it is...
Article
Full-text available
Wind energy has become an important source of electricity generation, with the aim of achieving a cleaner and more sustainable energy model. However, wind turbine performance improvement is required to compete with conventional energy resources. To achieve this improvement, flow control devices are implemented on airfoils. Computational fluid dynam...
Article
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The conduct of respiratory droplets is the basis of the study to reduce the spread of a virus in society. The pandemic suffered in early 2020 due to COVID-19 shows the lack of research on the evaporation and fate of droplets exhaled in the environment. The current study, attempts to provide solution through computational fluid dynamics techniques b...
Article
One of the challenges of air jet impingement systems is the interaction between jets in the case of impingement with nozzle arrays. This study is focused on the wall shear stress exerted by the fluid, as it is closely related to surface heat transfer. The strengths and weaknesses of the different turbulence models for a specific case are highlighte...
Article
In the present work, an artificial neural network (ANN) will be developed to estimate the relative rotation and translation of the autonomous mobile robot (AMR). The ANN will work as an iterative closed point, which is commonly used with the singular value decomposition algorithm. This development will provide better resolution for a relative posit...
Article
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There is presently a need for more robust navigation algorithms for autonomous industrial vehicles. These have reasonably guaranteed the adequate reliability of the navigation. In the current work, the stability of a modified algorithm for collision-free guiding of this type of vehicle is ensured. A lateral control and a longitudinal control are im...
Article
This work evaluates the evolution of electrochemical parameters, such as voltage and impedance spectra, to determine the state of charge (SOC), state of health (SOH), and electrolyte level of vented NiCd batteries. Similar to previous studies on lead acid batteries, valuable results are presented for SOC estimation based on open-circuit voltage. So...
Preprint
Full-text available
Wind energy has become an important source of electricity generation, with the aim of achieving a cleaner and more sustainable energy model. However, wind turbine performance improvement is required to compete with conventional energy resources. To achieve this improvement, flow control devices are implemented on airfoils. Computational Fluid Dynam...
Article
Full-text available
In this study, a water reattachment length was calculated by adopting two different models. The first was based on Unsteady Reynolds-Averaged Navier–Stokes (URANS) k-omega with Shear Stress Transport (SST); the second was a Large Eddy Simulation (LES) with Wall-Adapting Local Eddy-Viscosity (WALE). Both models used the same mesh and were checked wi...
Article
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Abstract: Flow control device modeling is an engaging research field for wind turbine optimization, since in recent years wind turbines have grown in proportions and weight. The purpose of the present work was to study the performance and effects generated by a rotating microtab (MT) implemented on the trailing edge of a DU91W250 airfoil through th...
Article
Full-text available
Turbulence in fluids has been a popular research topic for many years due to its influence on a wide range of applications. Computational Fluid Dynamics (CFD) tools are able to provide plenty of information about this phenomenon, but their computational cost often makes the use of these tools unfeasible. For that reason, in recent years, turbulence...
Article
Full-text available
The computational cost and memory demand required by computational fluid dynamics (CFD) codes simulations can become very high. Therefore, the application of convolutional neural networks (CNN) in this field has been studied owing to its capacity to learn patterns from sets of input data, which can considerably approximate the results of the CFD si...
Article
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The protection provided by wearing masks has been a guideline worldwide to prevent the risk of COVID-19 infection. The current work presents an investigation that analyzes the effectiveness of face shields as personal protective equipment. To that end, a multiphase computational fluid dynamic study based on Eulerian–Lagrangian techniques was define...
Article
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Obtaining tools to analyze and predict the performance of batteries is a non-trivial challenge because it involves non-destructive evaluation procedures. At the research level, the development of sensors to allow cell-level monitoring is an innovative path, and electrochemical impedance spectrometry (EIS) has been identified as one of the most prom...
Article
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This work presents a battery management system for lead-acid batteries that integrates a battery-block (12 V) sensor that allows the online monitoring of a cell's temperature, voltage, and impedance spectra. The monitoring and diagnostic capabilities enable the implementation of improved battery management algorithms in order to increase the life e...
Article
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The COVID-19 pandemic has pointed to the need to increase our knowledge in fields related to human breathing. In the present study, temperature, relative humidity, carbon dioxide (CO2) concentration, and median particle size diameter measurements were taken into account. These parameters were analyzed in a computer classroom with 15 subjects during...
Article
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This work presents the results of experimental analysis of the correlation between open-circuit voltage at 0% and the state of charge of a set (3 × 6) of high-temperature valve-regulated lead acid batteries, which provides a valuable health diagnosis tool when performing predictive maintenance actions. The proposed test could be executed after any...
Chapter
The design procedure of a Machine Learning (ML) based yaw control strategy for a Horizontal Axis Wind Turbine (HAWT) is presented in the following chapter. The proposed yaw control strategy is based on the interaction of three different Artificial Intelligence (AI) techniques to design a ML system: Reinforcement Learning (RL), Artificial Neural Net...
Article
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Vortex Generators (VGs) are applied before the expected region of separation of the boundary layer in order to delay or remove the flow separation. Although their height is usually similar to that of the boundary layer, in some applications, lower VGs are used, Sub-Boundary Layer Vortex Generators (SBVGs), since this reduces the drag coefficient. N...
Article
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The coronavirus disease 2019 (COVID-19) outbreak has altered the lives of everyone on a global scale due to its high transmission rate. In the current work, the droplet dispersion and evaporation originated by a cough at different velocities is studied. A multiphase computational fluid dynamic model based on fully coupled Eulerian–Lagrangian techni...
Article
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Differential evolution (DE) is a simple and efficient population-based stochastic algorithm for solving global numerical optimization problems. DE largely depends on algorithm parameter values and search strategy. Knowledge on how to tune the best values of these parameters is scarce. This paper aims to present a consistent methodology for tuning o...
Article
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One of the materials that is used widely for wind turbine blade manufacturing are fiber-reinforced composites. Although glass fiber reinforcement is the most used in wind turbine blades, the use of carbon fiber allows larger blades to be manufactured due to their better mechanical characteristics. Some turbine manufacturers are using carbon fiber i...
Chapter
One of the implementations of novel initiatives in the field of education that requires more efforts is the entire implementation of a new Bachelor’s degree based on dual training. These efforts involve on one hand the design of an extremely experimental degree and on the other hand, the engagement of local companies that must collaborate in a rigo...
Chapter
Autonomous Mobile Robots (AMR) need a positioning function to move into unknown areas. These kinds of vehicles do not use a magnetic tape to guide into warehouses. Therefore, AMR use two different alternative techniques to solve the localization problem. First one is based on absolute positioning, and second one is established on relative localizat...
Article
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Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in the energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long lif...
Article
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Microtabs (MTs) are a regularly used flow control device in terms of wind turbine optimization. The present study introduces the application of the novel cell-set model for an MT implementation on a DU91W(2)250 airfoil. The cell-set model is based on the reusability of a mesh to add new geometries on the domain; the matching geometry is located whe...
Article
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In this work, a semi-submersible piezoelectric energy harvester was used to provide power to a low-cost 4G Arduino shield. Initially, unsteady Reynolds averaged Navier-Stokes (URANS)-based simulations were conducted to investigate the dynamic forces under different conditions. An adaptive differential evolution (JADE) multivariable optimization alg...
Article
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Considering the increasing integration of renewable energies into the power grid, batteries are expected to play a key role in the challenge of compensating the stochastic and intermittent nature of these energy sources. Besides, the deployment of batteries can increase the benefits of a renewable power plant. One way to increase the profits with b...
Article
Full-text available
In this article authors propose a temperature based Maximum Power Point Tracking algorithm (MPPT). Authors show that there is an optimal current vs maximum power curve that depends on photovoltaic (PV) module temperature. Therefore, the maximum power point (MPP) can be achieved in very few commutation steps if the control forces the PV module to wo...
Article
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Over the last few years, the advances in size and weight for wind turbines have led to the development of flow control devices. The current work presents an innovative method to model flow control devices based on a cell-set model, such as Gurney flaps (GFs). This model reuses the cells which are around the required geometry and a wall boundary con...
Article
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The photovoltaic cell temperature is a key factor in solar energy harvesting. Solar radiation raises temperature on the cell, lowering its peak efficiency. Air jet impingement is a high heat transfer rate system and has been previously used to cool the back surface of photovoltaic modules and cells. In this work, an experimental comparison of the c...
Article
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Wind energy has recently become one of the most prominent technologies among electrical energy generation systems. As a result, wind-based renewable energy generation systems are incessantly growing, and wind turbines of different characteristics are being installed in many locations around the world. One drawback associated with different characte...
Article
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In this study, a semantic segmentation network is presented to develop an indoor navigation system for a mobile robot. Semantic segmentation can be applied by adopting different techniques, such as a convolutional neural network (CNN). However, in the present work, a residual neural network is implemented by engaging in ResNet-18 transfer learning...
Article
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Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-61...
Article
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Deep integration of renewable energies into the electricity grid is restricted by the problems related to their intermittent and uncertain nature. These problems affect both system operators and renewable power plant owners since, due to the electricity market rules, plants need to report their production some hours in advance and are, hence, expos...
Article
Full-text available
The yaw angle control of a wind turbine allows maximization of the power absorbed from the wind and, thus, the increment of the system efficiency. Conventionally, classical control algorithms have been used for the yaw angle control of wind turbines. Nevertheless, in recent years, advanced control strategies have been designed and implemented for t...
Article
Full-text available
Vortex generators (VGs) are used increasingly more by the wind turbine manufacture industry as flow control devices to improve rotor blade aerodynamic performance. The VG height is usually designed with equal thickness of the local boundary layer at the VG position. Nevertheless, these conventional VGs may produce excess residual drag in some appli...
Article
Improving the performance and the production of renewable energy sources, especially the wind energy, is considered an attractive approach to reduce the Cost of Energy (COE) associated to the hydrogen generation process. In this context, flow control strategies have been object of detailed investigation during last years. Originally flow control de...
Article
Full-text available
The considerable increase of wind turbine rotor size and weight in the last years has made impossible to control as they were controlled 20 years ago. The cost of energy is an essential role to maintain this type of energy as a viable alternative in economic terms with traditional or other renewable energies. Through the last decades many different...
Article
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Artificial Neural Networks (ANNs) have proven to be a powerful tool in many fields of knowledge. At the same time, evolutionary algorithms show a very efficient technique in optimization tasks. Historically, ANNs are used in the training process of supervising networks by decreasing the error between the output and the target. However, we propose a...
Article
Energy storage is one of the levers of change for energy transition. The take-off of this technology is unquestionable and unstoppable. Europe has historically been, together with the USA, one of the driving forces behind storage technologies, however, the manufacturing of a large proportion of these technologies has been left in the hands of Asian...
Article
Full-text available
Vibration energy harvesting (VeH) techniques by means of intentionally designed mechanisms have been used in the last decade for frequency bandwidth improvement under excitation for adequately high-vibration amplitudes. Oil, gas, and water are vital resources that are usually transported by extensive pipe networks. Therefore, wireless self-powered...
Article
Energy storage is one of the change levers for the energy transition. The takeoff of this technology is unquestionable and unstoppable. Europe has historically been, together with the USA, one of the drivers of storage technologies, but the manufacture of a large proportion of these technologies has been left in the hands of Asian countries. Aware...
Article
The development of tools for examining and predicting battery performance represents a significant challenge for the field of monitoring, as it is dependent on nondestructive evaluation (NDE) techniques to provide key behavior descriptors. As the thermal behavior of a battery impacts its internal chemistry, thermal imaging represents an in operando...
Article
Full-text available
The aim of this paper is to improve the dynamic window approach algorithm for mobile robots by implementing a prediction window with a fuzzy inference system to adapt to fixed parameters, depending on the surrounding conditions. The first implementation shows the advantage of the prediction step in terms of optimizing the path selection. The second...
Article
Full-text available
Orthotic devices are defined as externally applied devices that are used to modify the structural and functional characteristics of the neuro-muscular and skeletal systems. The aim of the current study is to improve the control and movement of a robotic arm orthosis by means of an intelligent optimization system. Firstly, the control problem settle...
Conference Paper
Full-text available
Considering the increasing integration of renewable energies into the electricity grid, batteries are expected to play a key role in the challenge of compensating the stochastic and intermittent nature of these energy sources. Besides, deployment of batteries can increase the benefits of a renewable power plant. In this paper, a hybrid renewable en...
Chapter
In this paper authors introduce an ongoing Educational Innovation Project (EIP) that is being carried out at the Faculty of Engineering of Vitoria-Gasteiz (Basque Country University, UPV/EHU, Spain). Since it is interesting from the point of view of universities, research institutes and even traditional companies, the aim of the project is to intro...
Article
Vortex generators are passive devices employed to improve the aerodynamic performance of aircraft and wind turbine blades. More concretely, these devices have high potential in improving the power output of wind turbines that are producing less power than expected. Besides, it can improve the aerodynamic performance of the nearest parts to the roto...
Article
Full-text available
Flow control devices have been introduced in the wind energy sector to improve the aerodynamic behavior of the wind turbine blades (WTBs). Among these flow control devices, Gurney flaps (GFs) have been the focus of innovative research, due to their good characteristics which enhance the lift force that causes the rotation of the wind turbine rotor....