Browsing by Keyword "Atomic and Molecular Physics, and Optics"
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Item 3D convolutional neural networks initialized from pretrained 2D convolutional neural networks for classification of industrial parts(2021-02-04) Merino, Ibon; Azpiazu, Jon; Remazeilles, Anthony; Sierra, Basilio; ROBOTICA_FLEX; Medical TechnologiesDeep learning methods have been successfully applied to image processing, mainly using 2D vision sensors. Recently, the rise of depth cameras and other similar 3D sensors has opened the field for new perception techniques. Nevertheless, 3D convolutional neural networks perform slightly worse than other 3D deep learning methods, and even worse than their 2D version. In this paper, we propose to improve 3D deep learning results by transferring the pretrained weights learned in 2D networks to their corresponding 3D version. Using an industrial object recognition context, we have analyzed different combinations of 3D convolutional networks (VGG16, ResNet, Inception ResNet, and EfficientNet), comparing the recognition accuracy. The highest accuracy is obtained with EfficientNetB0 using extrusion with an accuracy of 0.9217, which gives comparable results to state-of-the art methods. We also observed that the transfer approach enabled to improve the accuracy of the Inception ResNet 3D version up to 18% with respect to the score of the 3D approach alone.Item Analysing Edge Computing Devices for the Deployment of Embedded AI(2023-12) Garcia-Perez, Asier; Miñón, Raúl; Torre-Bastida, Ana I.; Zulueta-Guerrero, Ekaitz; HPAIn recent years, more and more devices are connected to the network, generating an overwhelming amount of data. This term that is booming today is known as the Internet of Things. In order to deal with these data close to the source, the term Edge Computing arises. The main objective is to address the limitations of cloud processing and satisfy the growing demand for applications and services that require low latency, greater efficiency and real-time response capabilities. Furthermore, it is essential to underscore the intrinsic connection between artificial intelligence and edge computing within the context of our study. This integral relationship not only addresses the challenges posed by data proliferation but also propels a transformative wave of innovation, shaping a new era of data processing capabilities at the network’s edge. Edge devices can perform real-time data analysis and make autonomous decisions without relying on constant connectivity to the cloud. This article aims at analysing and comparing Edge Computing devices when artificial intelligence algorithms are deployed on them. To this end, a detailed experiment involving various edge devices, models and metrics is conducted. In addition, we will observe how artificial intelligence accelerators such as Tensor Processing Unit behave. This analysis seeks to respond to the choice of a device that best suits the necessary AI requirements. As a summary, in general terms, the Jetson Nano provides the best performance when only CPU is used. Nevertheless the utilisation of a TPU drastically enhances the results.Item Analysis of the Refined Mean-Field Approximation for the 802.11 Protocol Model(2022-11) Ispizua, Begoña; Doncel, Josu; IAMean-field approximation is a method to investigate the behavior of stochastic models formed by a large number of interacting objects. A new approximation was recently established, i.e., the refined mean-field approximation, and its high accuracy when the number of objects is small has been shown. In this work, we consider the model of the 802.11 protocol, which is a discrete-time model and show how the refined mean-field approximation can be adapted to this model. Our results confirm the accuracy of the refined mean-field approximation when the model with N objects is in discrete time.Item Automatic pigmented lesion segmentation through a dermoscopy-guided OCT approach for early diagnosis(2019) López Sarachaga, Cristina; Lage, Sergio; Morales, Maria Celia; Boyano, Mª Dolores; Asumendi, Aintzane; Garrote, Estibaliz; Conde, Olga M.; Boyano, Ma Dolores; VISUAL; QuantumEarly diagnosis of pigmented lesions, specially melanoma, is an unmet clinical need that would help to improve patient prognosis. Apart from histopathological biopsy, the only gold standard non-invasive imaging technique during diagnosis is dermatoscopy (DD). Over the last years, new medical imaging techniques are being developed and Optical Coherence Tomography (OCT) has demonstrated to be very helpful on dermatology. OCT is non-invasive and provides in-depth structural microscopic information of the skin in real-time. In comparison with other novel techniques, as Reflectance Confocal Microscopy (RCM), the acquisition time is lower and the field-of-view higher. Hence, consolidated diagnosis techniques and novel imaging modalities can be combined to improve decision making during diagnosis and treatment. With actual methods, the delineation of lesion margins directly on OCT images during early stages of the disease is still really challenging and, at the same time, relevant from a prognosis perspective. This work proposes combining DD and OCT images to take advantage of their complementary information. The goal is to guide lesions delineation on OCT images considering the clinical features on DD images. The developed method applies image processing techniques to DD image to automatically segment the lesion; later, and after a calibration procedure, DD and OCT images become coregistered. In a final step the DD segmentation is transferred into the OCT image. Applying advanced image processing techniques and the proposed strategy of lesion delimitation, histopathological characteristics of the segmented lesion can be studied on OCT images afterwards. This proposal can lead to early, real-time and non-invasive diagnosis of pigmented lesions.Item Can Shared Control Improve Overtaking Performance? Combining Human and Automation Strengths for a Safer Maneuver(2022-12) Marcano, Mauricio; Tango, Fabio; Sarabia, Joseba; Chiesa, Silvia; Pérez, Joshué; Díaz, Sergio; CCAMThe Shared Control (SC) cooperation scheme, where the driver and automated driving system control the vehicle together, has been gaining attention through the years as a promising option to improve road safety. As a result, advanced interaction methods can be investigated to enhance user experience, acceptance, and trust. Under this perspective, not only the development of algorithms and system applications are needed, but it is also essential to evaluate the system with real drivers, assess its impact on road safety, and understand how drivers accept and are willing to use this technology. In this sense, the contribution of this work is to conduct an experimental study to evaluate if a previously developed shared control system can improve overtaking performance on roads with oncoming traffic. The evaluation is performed in a Driver-in-the-Loop (DiL) simulator with 13 real drivers. The system based on SC is compared against a vehicle with conventional SAE-L2 functionalities. The evaluation includes both objective and subjective assessments. Results show that SC proved to be the best solution for assisting the driver during overtaking in terms of safety and acceptance. The SC’s longer and smoother control transitions provide benefits to cooperative driving. The System Usability Scale (SUS) and the System Acceptance Scale (SAS) questionnaire show that the SC system was perceived as better in terms of usability, usefulness, and satisfaction.Item Collaboration-Centred Cities through Urban Apps Based on Open and User-Generated Data(2016-07-01) Aguilera, Unai; López-de-Ipiña, Diego; Pérez-Velasco, Jorge; Tecnalia Research & InnovationThis paper describes the IES Cities platform conceived to streamline the development of urban apps that combine heterogeneous datasets provided by diverse entities, namely, government, citizens, sensor infrastructure and other information data sources. This work pursues the challenge of achieving effective citizen collaboration by empowering them to prosume urban data across time. Particularly, this paper focuses on the query mapper; a key component of the IES Cities platform devised to democratize the development of open data-based mobile urban apps. This component allows developers not only to use available data, but also to contribute to existing datasets with the execution of SQL sentences. In addition, the component allows developers to create ad hoc storages for their applications, publishable as new datasets accessible by other consumers. As multiple users could be contributing and using a dataset, our solution also provides a data level permission mechanism to control how the platform manages the access to its datasets. We have evaluated the advantages brought forward by IES Cities from the developers' perspective by describing an exemplary urban app created on top of it. In addition, we include an evaluation of the main functionalities of the query mapper.Item Compact LED based nanoimprinter for UV-NIL(2011-11) Khokhar, Ali Z.; Gaston, Ainhoa; Obieta, Isabel; Gadegaard, Nikolaj; Tecnalia Research & InnovationUV-based nanoimprint lithography (UV-NIL) is a cheap and fast way to imprint patterns ranging from nanometres to micrometres. However, commonly used equipment can be expensive and require a clean room infrastructure. Here we present the design and testing of a simple UV-NIL system based on a light emitting diode. The current design permits imprints of 10 × 10 mm 2 in size using a 25 × 25 mm2 master. This printer can be used in a semi-clean environment such as a laminar flow bench. The imprinter was used to imprint photoresists as well as UV sensitised hydrogels. The best results were obtained using SU-8 photoresist with features down to 50 nm in size, only limited by the imprint master. Patterns in SU-8 resist were also transferred into silicon substrates by reactive ion etching demonstrating its full potential as a lithographic tool.Item A Complete Framework for a Behavioral Planner with Automated Vehicles: A Car-Sharing Fleet Relocation Approach(2022-11) Arizala, Asier; Zubizarreta, Asier; Pérez, Joshué; CCAMCurrently, research on automated vehicles is strongly related to technological advances to achieve a safe, more comfortable driving process in different circumstances. The main achievements are focused mainly on highway and interurban scenarios. The urban environment remains a complex scenario due to the number of decisions to be made in a restrictive context. In this context, one of the main challenges is the automation of the relocation process of car-sharing in urban areas, where the management of the platooning and automatic parking and de-parking maneuvers needs a solution from the decision point of view. In this work, a novel behavioral planner framework based on a Finite State Machine (FSM) is proposed for car-sharing applications in urban environments. The approach considers four basic maneuvers: platoon following, parking, de-parking, and platoon joining. In addition, a basic V2V communication protocol is proposed to manage the platoon. Maneuver execution is achieved by implementing both classical (i.e., PID) and Model-based Predictive Control (i.e., MPC) for the longitudinal and lateral control problems. The proposed behavioral planner was implemented in an urban scenario with several vehicles using the Carla Simulator, demonstrating that the proposed planner can be helpful to solve the car-sharing fleet relocation problem in cities.Item The conformation of chloramphenicol in the ordered and disordered phases(2019-03-15) Meaurio, Emilio; Sanchez-Rexach, Eva; Butron, Amaia; Sarasua, Jose-Ramon; BIOECONOMÍA Y CO2The conformational behavior of chloramphenicol (CHL) in the solid, liquid and vapor phases is revisited here by means of FTIR spectroscopy and QM methods. In the crystalline phase, both the IR analysis and QM computations discard the conformer proposed by Acharya et al. (Acta Cryst., 1979, B35:1360–1363) and support the one proposed by Chatterjee et al. (J. Cryst. Mol. Struct., 1979, 9:295–304), characterized by an intramolecular O–H⋯O hydrogen bond in which the primary hydroxyl group acts as hydrogen bond donor. The conformational behavior of CHL in the liquid and gas phases has been analyzed using QM calculations. The Self-Consistent Reaction Field (SCRF) method with the Onsager solvation model has been used for the initial optimizations in solution, and the lowest energy conformers have been refined using the Solvation Model based on Density (SMD). In solution environment the intramolecular O–H⋯O hydrogen bond in CHL is reversed so that the secondary hydroxyl group acts as hydrogen bond donor. In addition, the dichloroacetamide group folds back further over the phenyl ring to form an intramolecular C–Cl⋯π halogen bond. Two different halogen bonds are actually observed (each one with a different chlorine atom) resulting in two different stable conformers, that can be detected by FTIR spectroscopy due to the conformational sensitivity of the C[dbnd]O group to the conformation of the dichloroacetyl group. Finally, the stability of the conformers with the polarity of the medium is also discussed.Item Continuous quantitative risk management in smart grids using attack defense trees(2020-08-07) Rios, Erkuden; Rego, Angel; Iturbe, Eider; Higuero, Marivi; Larrucea, Xabier; CIBERSEC&DLT; Tecnalia Research & InnovationAlthough the risk assessment discipline has been studied from long ago as a means to support security investment decision-making, no holistic approach exists to continuously and quantitatively analyze cyber risks in scenarios where attacks and defenses may target different parts of Internet of Things (IoT)-based smart grid systems. In this paper, we propose a comprehensive methodology that enables informed decisions on security protection for smart grid systems by the continuous assessment of cyber risks. The solution is based on the use of attack defense trees modelled on the system and computation of the proposed risk attributes that enables an assessment of the system risks by propagating the risk attributes in the tree nodes. The method allows system risk sensitivity analyses to be performed with respect to different attack and defense scenarios, and optimizes security strategies with respect to risk minimization. The methodology proposes the use of standard security and privacy defense taxonomies from internationally recognized security control families, such as the NIST SP 800-53, which facilitates security certifications. Finally, the paper describes the validation of the methodology carried out in a real smart building energy efficiency application that combines multiple components deployed in cloud and IoT resources. The scenario demonstrates the feasibility of the method to not only perform initial quantitative estimations of system risks but also to continuously keep the risk assessment up to date according to the system conditions during operation.Item Corrosion and thermal shock resistance of metal (Cu, Al) matrix composites reinforced by SiC particles(2020-10) Strojny-Nędza, A.; Egizabal, P.; Pietrzak, K.; Zieliński, R.; Kaszyca, K.; Piątkowska, A.; Chmielewski, M.; Tecnalia Research & InnovationThis paper presents the results of studies concerning the production and characterization of Al-SiC/W and Cu-SiC/W composite materials with a 30% volume fraction of reinforcing phase particles as well as the influence of corrosion and thermal shocks on the properties of selected metal matrix composites. Spark plasma sintering method (SPS) was applied for the purpose of producing these materials. In order to avoid the decomposition of SiC surface, SiC powder was coated with a thin tungsten layer using plasma vapour deposition (PVD) method. The obtained results were analysed by the effect of the corrosion and thermal shocks on materials density, hardness, bending strength, tribological and thermal properties. Qualitative X-ray analysis and observation of microstructure of sample surfaces after corrosion tests and thermal shocks were also conducted. The use of PVD technique allows us to obtain an evenly distributed layer of titanium with a constant thickness of 1.5 µm. It was found that adverse environmental conditions and increased temperature result in a change in the material behaviour in wear tests.Item Direct Fabrication of a Copper RTD over a Ceramic-Coated Stainless-Steel Tube by Combination of Magnetron Sputtering and Sol–Gel Techniques(2023-06) Bikarregi, Aitor; Dominguez, Santiago; Brizuela, Marta; López, Alejandra; Suarez-Vega, Ana; Agustín-Sáenz, Cecilia; Presa, Micael; López, Gabriel A.; INGENIERÍA DE SUPERFICIES; VALORIZACIÓN DE RESIDUOSReducing the economic and environmental impact of industrial process may be achieved by the smartisation of different components. In this work, tube smartisation is presented via direct fabrication of a copper (Cu)-based resistive temperature detector (RTD) on their outer surfaces. The testing was carried out between room temperature and 250 °C. For this purpose, copper depositions were studied using mid-frequency (MF) and high-power impulse magnetron sputtering (HiPIMS). Stainless steel tubes with an outside inert ceramic coating were used after giving them a shot blasting treatment. The Cu deposition was performed at around 425 °C to improve adhesion as well as the electrical properties of the sensor. To generate the pattern of the Cu RTD, a photolithography process was carried out. The RTD was then protected from external degradation by a silicon oxide film deposited over it by means of two different techniques: sol–gel dipping technique and reactive magnetron sputtering. For the electrical characterisation of the sensor, an ad hoc test bench was used, based on the internal heating and the external temperature measurement with a thermographic camera. The results confirm the linearity (R2 > 0.999) and repeatability in the electrical properties of the copper RTD (confidence interval < 0.0005).Item Direct patterning of polymer optical periodic nanostructures on CYTOP for visible light waveguiding(2018-08) Diez, M.; Raimbault, V.; Joly, S.; Oyhenart, L.; Doucet, J. B.; Obieta, I.; Dejous, C.; Bechou, L.; Tecnalia Research & InnovationOptical waveguides and grating couplers based on polymer nanostructures are now considered as promising technologies for integrated biophotonic sensing systems. Commonly, structuration and patterning of polymers at the submicron scale requires the use of time and cost-consuming equipments such as electron beam lithography. Direct patterning of high refractive index polymer devices on CYTOP is now achievable and provides symmetric waveguides with top water-like claddings. In addition, transparency of polymers makes them suitable for operation in the visible range, being of major interest for biophotonic applications. In this paper, we report on the fabrication process of polymer submicronic single-mode waveguides on CYTOP for visible light operation. Sub-wavelength grating couplers with a pitch lower than 300 nm were fabricated to couple the input light into a 350 nm square cross-section waveguide. The whole device is imprinted in a single step using soft stamp lithography with a minimal residual layer. Finally, optical characterizations demonstrate a state-of-the-art transmission efficiency (around 1.5%) at the selected operating wavelength of 507 nm for different coupling angles in good agreement with simulations.Item Dual arm co-manipulation architecture with enhanced human–robot communication for large part manipulation(2020-10-29) Ibarguren, Aitor; Eimontaite, Iveta; Outón, José Luis; Fletcher, Sarah; ROBOTICA_AUTOMA; ROBOTICA_FLEXThe emergence of collaborative robotics has had a great impact on the development of robotic solutions for cooperative tasks nowadays carried out by humans, especially in industrial environments where robots can act as assistants to operators. Even so, the coordinated manipulation of large parts between robots and humans gives rise to many technical challenges, ranging from the coordination of both robotic arms to the human–robot information exchange. This paper presents a novel architecture for the execution of trajectory driven collaborative tasks, combining impedance control and trajectory coordination in the control loop, as well as adding mechanisms to provide effective robot-to-human feedback for a successful and satisfactory task completion. The obtained results demonstrate the validity of the proposed architecture as well as its suitability for the implementation of collaborative robotic systems.Item DVB-S2 and DVB-T RF transmission in 1-mm GI-POF system(2014-08-15) Beltrán, Marta; Cabezón, Xabier; Campo, Miguel A.; Trueba, Roberto; Lekue, Antonio; Pac, Jose M.; Cortés, Francisco J.; Llorente, Roberto; FACTORY; Tecnalia Research & InnovationAn optical system for the transmission of digital video broadcasting (DVB) signals is proposed and experimentally demonstrated. The transmission media comprises 1-mm diameter graded-index plastic optical fiber (GI-POF) with a relatively high bandwidth. The system is fully engineered using low-cost off-the-self components including a vertical-cavity surface-emitting laser, a silicon avalanche photodiode, POF connectors, and all integrated radio frequency (RF) circuitry. The RF distribution of standard DVB-satellite second generation signals in 950-2150 MHz and DVB-terrestrial signals in 470-790 MHz over 25-m GI-POF is successfully demonstrated.Item Efficient broadband polarization retarder via shortcuts to adiabaticity(2023-09-01) Wang, Wei; Ban, Yue; Chen, Xi; Tecnalia Research & Innovation; QuantumThe use of two-level atomic systems in quantum optics allows for the design of highly efficient and broadband achromatic retarders through the application of adiabatic passage and composite pulse techniques. In this work, we propose shortcuts to adiabaticity to improve broadband polarization retarders with shorter lengths. We achieve this by inversely engineering the relative refractive indices and further optimizing them with respect to the perturbation of input wavelength. Our results are compared with adiabatic and composite protocols, demonstrating that our method provides the advantage of integrating efficiency and robustness.Item Electrotactile Communication via Matrix Electrode Placed on the Torso Using Fast Calibration, and Static vs. Dynamic Encoding(2022-10) Malešević, Jovana; Kostić, Miloš; Jure, Fabricio A.; Spaich, Erika G.; Došen, Strahinja; Ilić, Vojin; Bijelić, Goran; Štrbac, Matija; SGElectrotactile stimulation is a technology that reproducibly elicits tactile sensations and can be used as an alternative channel to communicate information to the user. The presented work is a part of an effort to develop this technology into an unobtrusive communication tool for first responders. In this study, the aim was to compare the success rate (SR) between discriminating stimulation at six spatial locations (static encoding) and recognizing six spatio-temporal patterns where pads are activated sequentially in a predetermined order (dynamic encoding). Additionally, a procedure for a fast amplitude calibration, that includes a semi-automated initialization and an optional manual adjustment, was employed and evaluated. Twenty subjects, including twelve first responders, participated in the study. The electrode comprising the 3 × 2 matrix of pads was placed on the lateral torso. The results showed that high SRs could be achieved for both types of message encoding after a short learning phase; however, the dynamic approach led to a statistically significant improvement in messages recognition (SR of 93.3%), compared to static stimulation (SR of 83.3%). The proposed calibration procedure was also effective since in 83.8% of the cases the subjects did not need to adjust the stimulation amplitude manually.Item Enhanced Flexibility and Reusability through State Machine-Based Architectures for Multisensor Intelligent Robotics(2017-06) Herrero, Héctor; Outón, Jose; Puerto, Mildred; Sallé, Damien; López de Ipiña, Karmele; Tecnalia Research & Innovation; ROBOTICA_FLEX; FACTORYThis paper presents a state machine-based architecture, which enhances the flexibility and reusability of industrial robots, more concretely dual-arm multisensor robots. The proposed architecture, in addition to allowing absolute control of the execution, eases the programming of new applications by increasing the reusability of the developed modules. Through an easy-to-use graphical user interface, operators are able to create, modify, reuse and maintain industrial processes, increasing the flexibility of the cell. Moreover, the proposed approach is applied in a real use case in order to demonstrate its capabilities and feasibility in industrial environments. A comparative analysis is presented for evaluating the presented approach versus traditional robot programming techniques.Item Enhanced millimeter-wave transmission through subwavelength hole arrays(2004-11-01) Beruete, M.; Sorolla, M.; Campillo, I.; Dolado, J. S.; Martín-Moreno, L.; Bravo-Abad, J.; García-Vidal, F. J.; Tecnalia Research & InnovationWe explore, both experimentally and theoretically, the existence in the millimeter-wave range of the phenomenon of extraordinary light transmission through arrays of subwavelength holes. We have measured the transmission spectra of several samples made on aluminum wafers by use of an AB Millimetre quasi-optical vector network analyzer in the wavelength range 4.2-6.5 mm. Clear signals of the existence of resonant light transmission at wavelengths close to the period of the array appear in the spectra.Item Equimetrix Device: Criteria Based Validation and Reliability Analysis of the Center of Mass and Base of Support of a Human Postural Assessment System: criteria based validation and reliability analysis of the center of mass and base of support of a human postural assessment system(2021-01-07) Fonseca, Pedro; Sousa, Manoela; Sebastião, Ricardo; Goethel, Márcio; Barralon, Pierre; Idigoras, Igone; Sousa, Filipa; Machado, Leandro; Vilas-Boas, João Paulo; Medical TechnologiesHuman postural control is a fundamental ability for static and dynamic tasks, especially in hiper-and hipo-functional populations, such as the elderly. The Equimetrix is a clinical device developed to assess both the base of support (BoS) and the center of mass (CoM) dynamics, thus allowing their use as new evaluation and training tools. This study aims to perform a criteria based validation of Equimetrix by comparing the BoS and CoM data with gold-standard equipment. A motion capture system, force platform, and pressure mat were used to calculate the CoM, center of pressure (CoP) and BoS during bipedal, unipedal, feet together and full tandem stances. Results demonstrate an excellent reliability of Equimetrix in terms of spatial accuracy of the CoM, although over-estimating the CoM height. Differences were found when comparing Mean velocity Path with the CoM, but not with the CoP, indicating a lower reliability in time-based parameters. The Equimetrix presents a tendency to overestimate the BoS, with mixed reliability values, which may be related to the different size of sensing elements between the Equimetrix and the pressure sensing mat. These are encouraging results that should be further explored during dynamic tasks.