Investigaciones financiadas por la Unión Europea (OpenAire) - Europar Batasunak finantzatutako ikerketak (OpenAire)

Permanent URI for this collection

http://hdl.handle.net/2454/24408

Browse

Now showing 1 - 20 of 53

Open Access
Addressing the issue of trust in elementary teachers' maths-specific education: ANFoMAM project
(Charles University (Chequia), 2019) Celi, Valentina; Cogolludo, José Ignacio; Gil Clemente, Elena; Lizasoain Iriso, María Inmaculada; Millán Gasca, Ana; Moler Cuiral, José Antonio; Regoliosi, Luigi; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
To improve primary school teachers' maths-specific education at university, our project will develop a series of workshops, as ready-to-use instruments, which closely consider children's way of learning and their relationship with mathematics. Thus, the interest of participants in children is exploited in sessions which take into account both their professional work as teachers and their own childhood experiences. The aim is to help participants to evolve in the key aspect of trust. The paper describes the objectives and first results of the ANFoMAM project, supported by the Erasmus Plus Programme in the area of strategic partnerships for innovation in higher education in Europe.
Open Access
Aggregator to electric vehicle LoRaWAN based communication analysis in vehicle-to-grid systems in smart cities
(IEEE, 2020) Klaina, Hicham; Picallo Guembe, Imanol; López Iturri, Peio; Astrain Escola, José Javier; Azpilicueta Fernández de las Heras, Leyre; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Estadística, Informática y Matemáticas
Recently, there has been growing attention to the power grid management due to the increasing concerns on global warming. With the advancement in electric vehicles (EV) industry and the evolution in batteries, EVs become an important contributor to the grid with capability of bidirectional power exchange with the grid. In this context, Vehicle-to-Grid (V2G) systems enable multiple functionalities between EVs and the corresponding aggregator. Thus, reliable, long-range communication capabilities between aggregator and EVs is compulsory. In this paper, wireless channel analysis for aggregator and electrical vehicle communication using Long-Range Wide Area Network (LoRaWAN) technology in V2G is presented, in order to test a low-cost solution with large coverage and reduced power consumption profile. Wireless channel and system-level measurements have been performed in a real urban scenario between EV's charging station in Pamplona (Spain) and a vehicle in motion using LoRaWAN 868 MHz devices. Wireless channel characterization is performed by implementing a full 3D urban scenario model, including elements such as buildings, vehicles, users and urban infrastructure such as lamp posts and benches. By means of in-house developed 3D Ray Launching algorithm with hybrid simulation capabilities, estimations of received power levels, signal to noise ratio and time domain parameters have been obtained, for the complete volume of the scenario under test in dense urban conditions. V2G end to end communication has been validated by implementing an intra-vehicle Controller Area Network-BUS (CAN BUS) data gathering system connected to the vehicle LoRaWAN transceiver and subsequently, to a cloud-based web service. The results show that the accurate deterministic based radio channel analysis enables to optimize the network design of LoRaWAN networks in a vehicular environment, considering inter-vehicular and infrastructure links, enabling scalable, low cost end to end data exchange for the deployment of ancillary V2G services.
Open Access
Analysis of the suitability of the EOLO wind-predictor model for the spanish electricity markets
(MDPI, 2023) Martínez-Lastras, Saray; Frías Paredes, Laura; Prieto-Herráez, Diego; Gastón Romeo, Martín; González-Aguilera, Diego; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Wind energy forecasting is a critical aspect for wind energy producers, given that the chaotic nature and the intermittence of meteorological wind cause difficulties for both the integration and the commercialization of wind-produced electricity. For most European producers, the quality of the forecast also affects their financial outcomes since it is necessary to include the impact of imbalance penalties due to the regularization in balancing markets. To help wind farm owners in the elaboration of offers for electricity markets, the EOLO predictor model can be used. This tool combines different sources of data, such as meteorological forecasts, electric market information, and historic production of the wind farm, to generate an estimation of the energy to be produced, which maximizes its financial performance by minimizing the imbalance penalties. This research study aimed to evaluate the performance of the EOLO predictor model when it is applied to the different Spanish electricity markets, focusing on the statistical analysis of its results. Results show how the wind energy forecast generated by EOLO anticipates real electricity generation with high accuracy and stability, providing a reduced forecast error when it is used to participate in successive sessions of the Spanish electricity market. The obtained error, in terms of RMAE, ranges from 8%, when it is applied to the Day-ahead market, to 6%, when it is applied to the last intraday market. In financial terms, the prediction achieves a financial performance near 99% once imbalance penalties have been discounted.
Open Access
Analytical ray transfer matrix for the crystalline lens
(OSA Publishing, 2022) Navarro, Rafael; Lockett-Ruiz, Verónica; López García, José Luis; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
We present the formulation of a paraxial ray transfer or ABCD matrix for onion-type GRIN lenses. In GRIN lenses, each iso-indicial surface (IIS) can be considered a refracting optical surface. If each IIS is a shell or layer, the ABCD matrix of a GRIN lens is computed by multiplying a typically high number of translation and refraction matrices corresponding to the K layers inside the lens. Using a differential approximation for the layer thickness, this matrix product becomes a sum. The elements A, B, C, and D of the approximated GRIN ray transfer matrix can be calculated by integrating the elements of a single-layer matrix. This ABCD matrix differs from a homogeneous lens matrix in only one integration term in element C, corresponding to the GRIN contribution to the lens power. Thus the total GRIN lens power is the sum of the homogeneous lens power and the GRIN contribution, which offers a compact and simple expression for the ABDC matrix. We then apply this formulation to the crystalline lens and implement both numerical and analytical integration procedures to obtain the GRIN lens power. The analytical approximation provides an accurate solution in terms of Gaussian hypergeometric functions. Last, we compare our numerical and analytical procedures with published ABCD matrix methods in the literature, and analyze the effect of the iso-indicial surface’s conic constant (Q) and inner curvature gradient (G) on the lens power for different lens models.
Open Access
Comparing a mid-air two-hand pinching point-and-click technique with mouse, keyboard and touchfree
(Association for Computing Machinery, 2024-01-18) Lafuente Duque, Melchor; Elizondo Martínez, Sonia; Fernández Ortega, Unai Javier; Marzo Pérez, Asier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Some of our daily activities are performed by interacting with public touchscreens, such as food kiosks, bank tellers and newsstands. Nonetheless, the physical contact with these screens that are used by different people may be considered unhygienic. To avoid contact, some screens already integrate one-hand contactless interaction technologies, i.e. Leap Motion Controller, though they may lead to arm fatigue and slow performance. We present LeapPointer, a mid-Air two-hand pinching point-And-click technique. Specifically, this technique relies on a Leap Motion device to track both hands, and proposes a new software tool that allows bimanual selection through pointing and pinching gestures. A user study was performed to compare LeapPointer with two other techniques: The common mouse/keyboard and the current UltraLeap's TouchFree technique. Task completion time and accuracy as well as subjective data were gathered. The analysis of these data suggested that LeapPointer is significantly faster than the other touchless technique although less accurate. Self-reported fatigue was less with LeapPointer than with TouchFree.
Open Access
Comparison of experiment and simulation of ultrasonic mid-air haptic forces
(IEEE, 2022) Morales González, Rafael; Georgiou, Orestis; Marzo Pérez, Asier; Frier, William; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC
Ultrasound mid-air haptics is an emerging technology with many applications in human-computer interactions. Despite great advances in related hardware and software, physics models that predict the resulting forces on a surface (e.g., someone's hand) are either too simple (inaccurate) or too complex (computationally expensive). In this paper, we show that simple models are not sufficient when predicting the force on an experimental setup involving two prototype devices and a precision scale. Specifically, we demonstrate that our experimental measurements cannot be accurately predicted using a linear acoustic model.
Open Access
Contactless electrostatic piloerection for haptic sensations
(IEEE, 2023) Iriarte Cárdenas, Naroa; Ezcurdia Aguirre, Íñigo Fermín; Elizondo Martínez, Sonia; Irisarri Erviti, Josu; Hemmerling, Daria; Ortiz Nicolás, Amalia; Marzo Pérez, Asier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
In this project, we create artificial piloerection using contactless electrostatics to induce tactile sensations in a contactless way. Firstly, we design various high-voltage generators and evaluate them in terms of their static charge, safety and frequency response with different electrodes as well as grounding strategies. Secondly, a psychophysics user study revealed which parts of the upper body are more sensitive to electrostatic piloerection and what adjectives are associated with them. Finally, we combine an electrostatic generator to produce artificial piloerection on the nape with a head-mounted display, this device provides an augmented virtual experience related to fear. We hope that work encourages designers to explore contactless piloerection for enhancing experiences such as music, short movies, video games, or exhibitions.
Open Access
Content-aware image smoothing based on fuzzy clustering
(Springer, 2022) Antunes dos Santos, Felipe; López Molina, Carlos; Mir Fuentes, Arnau; Mendióroz Iriarte, Maite; Baets, Bernard de; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Literature contains a large variety of content-aware smoothing methods. As opposed to classical smoothing methods, content-aware ones intend to regularize the image while avoiding the loss of relevant visual information. In this work, we propose a novel approach to contentaware image smoothing based on fuzzy clustering, specifically the Spatial Fuzzy c-Means (SFCM) algorithm. We develop the proposal and put it to the test in the context of automatic analysis of immunohistochemistry imagery for neural tissue analysis.
Open Access
Cytokinins are involved in drought tolerance of Pinus radiata plants originating from embryonal masses induced at high temperatures
(Oxford University Press, 2021) Castander Olarieta, Ander; Moncaleán, Paloma; Pereira, Catia; Pěnčík, A.; Petřík, I.; Pavlović, I.; Novák, Ondrej; Strnad,Miroslav; Goicoa Mangado, Tomás; Ugarte Martínez, María Dolores; Montalbán, Itziar A.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Vegetative propagation through somatic embryogenesis is an effective method to produce elite varieties and can be applied as a tool to study the response of plants to different stresses. Several studies show that environmental changes during embryogenesis could determine future plant development. Moreover, we previously reported that physical and chemical conditions during somatic embryogenesis can determine the protein, hormone and metabolite profiles, as well as the micromorphological and ultrastructural organization of embryonal masses and somatic embryos. In this sense, phytohormones are key players throughout the somatic embryogenesis process as well as during numerous stress-adaptation responses. In this work, we first applied different higherature regimes (30 °C, 4 weeks; 40 °C, 4 days; 50 °C, 5 min) during induction of Pinus radiata D. Don somatic embryogenesis, together with control temperature (23 °C). Then, the somatic plants regenerated from initiated embryogenic cell lines and cultivated in greenhouse conditions were subjected to drought stress and control treatments to evaluate survival, growth and several physiological traits (relative water content, water potential, photosynthesis, stomatal conductance and transpiration). Based on those preliminary results, even more extreme higherature regimes were applied during induction (40 °C, 4 h; 50 °C, 30 min; 60 °C, 5 min) and the corresponding cytokinin profiles of initiated embryonal masses from different lines were analysed. The results showed that the temperature regime during induction had delayed negative effects on drought resilience of somatic plants as indicated by survival, photosynthetic activity and water- use efficiency. However, high temperatures for extended periods of time enhanced subsequent plant growth in well-watered conditions. Higherature regime treatments induced significant differences in the profile of total cytokinin bases, N6-isopentenyladenine, cis-zeatin riboside and trans-zeatin riboside. We concluded that phytohormones could be potential regulators of stress-response processes during initial steps of somatic embryogenesis and that they may have delayed implications in further developmental processes, determining the performance of the generated plants.
Open Access
Design of an immersive virtual reality framework to enhance the sense of agency using affective computing technologies
(MDPI, 2023) Ortiz Nicolás, Amalia; Elizondo Martínez, Sonia; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Virtual Reality is expanding its use to several fields of application, including health and education. The continuous growth of this technology comes with new challenges related to the ways in which users feel inside these virtual environments. There are various guidelines on ways to enhance users’ virtual experience in terms of immersion or presence. Nonetheless, there is no extensive research on enhancing the sense of agency (SoA), a phenomenon which refers to the self-awareness of initiating, executing, and controlling one’s actions in the world. After reviewing the state of the art of technologies developed in the field of Affective Computing (AC), we propose a framework for designing immersive virtual environments (IVE) to enhance the users’ SoA. The framework defines the flow of interaction between users and the virtual world, as well as the AC technologies required for each interactive component to recognise, interpret and respond coherently within the IVE in order to enhance the SoA.
Open Access
Distributed opportunistic wireless mapping system towards smart city service provision
(IEEE, 2021) Villadangos Alonso, Jesús; Falcone Lanas, Francisco; López Martín, Antonio; Astrain Escola, José Javier; Sanchis Gúrpide, Pablo; Matías Maestro, Ignacio; Estatistika, Informatika eta Matematika; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Estadística, Informática y Matemáticas; Ingeniería Eléctrica, Electrónica y de Comunicación
The knowledge of wireless signal distribution within an urban scenario can provide useful information to users as well as to enhance connectivity and device operation or to perform municipal logistics based on crowd density and user mobility patterns. In this work, a distributed wireless mapping system, based on a combination of opportunistic nodes such as smartphones which map geolocated WiFi access point connection and received power levels, and a cloud-based information gathering architecture is described. The proposed system has been tested in the framework of the Smart City platform of the city of Pamplona, providing signal distribution heat maps, which can be used for multiple municipal services.
Open Access
Electric vehicle routing, arc routing, and team orienteering problems in sustainable transportation
(MDPI, 2021) Carmo Martins, Leandro do; Tordecilla, Rafael D.; Castaneda, Juliana; Juan, Ángel A.; Faulín Fajardo, Javier; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC; Estadística, Informática y Matemáticas
The increasing use of electric vehicles in road and air transportation, especially in last-mile delivery and city mobility, raises new operational challenges due to the limited capacity of electric batteries. These limitations impose additional driving range constraints when optimizing the distribution and mobility plans. During the last years, several researchers from the Computer Science, Artificial Intelligence, and Operations Research communities have been developing optimization, simulation, and machine learning approaches that aim at generating efficient and sustainable routing plans for hybrid fleets, including both electric and internal combustion engine vehicles. After contextualizing the relevance of electric vehicles in promoting sustainable transportation practices, this paper reviews the existing work in the field of electric vehicle routing problems. In particular, we focus on articles related to the well-known vehicle routing, arc routing, and team orienteering problems. The review is followed by numerical examples that illustrate the gains that can be obtained by employing optimization methods in the aforementioned field. Finally, several research opportunities are highlighted.
Open Access
Enabling intelligent and interactive immersion in smart environments
(2022) Al-Rahamneh, Anas; Falcone Lanas, Francisco; Astrain Escola, José Javier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Gobierno de Navarra / Nafarroako Gobernua
In recent years, the Smart City concept has grown in popularity, and a significant number of cities around the world have adopted smart city strategies. Smart and sustainable cities are an emerging urban development approach due to their immense potential to improve environmental sustainability. The Smart City concept is based on collecting, analyzing, and displaying a large amount of data and information concerning urban systems and subsystems. As time goes by, the capacity of smart cities for generating digital information has grown exponentially. However, this digital information is heterogeneous, massive, collected from different sources, generated in different formats, and in most cases not structured, which exacerbates the situation of extracting valuable knowledge from data. Therefore, it is fundamental to handle the significant volumes of heterogeneous sensed data and to integrate such data along with information and analysis tools into a comprehensive platform. This can ensure the security, efficiency, and performance of the different Smart City tasks. A comprehensive software platform could provide services such as facilities for application development, integration of heterogeneous data sources, deployment, and management to ease the construction of sophisticated Smart Cities’ applications. In this context, the work begins with a concise description of the concept of smart city and the technologies involved in it. It addresses the development of an urban data platform along with how to obtain and integrate information from sensors and other data sources, in order to provide aggregated and intelligent views of raw data to support various domains within the city; in our case, smart mobility. The platform architecture is implemented following a five-layer model that considers elements from perception, sensing to data management, processing, and visualization. With the aim of evaluating the efficiency of the developed platform, three different use cases are described and analyzed, which have been implemented in the city of Pamplona, Spain, as vertical services linked to the platform: intelligent urban mobility-bike handling, bike-2-bike communication, and restricted vehicle access zone control system. Ultimately, this work provides an experiment to assess different long-range wireless communication technologies to enable their implementation within an urban environment.
Open Access
Enhancing the quality of amplitude patterns using time-multiplexed virtual acoustic fields
(American Institute of Physics, 2023) Elizondo Martínez, Sonia; Ezcurdia Aguirre, Íñigo Fermín; Goñi Carnicero, Jaime; Galar Idoate, Mikel; Marzo Pérez, Asier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Ultrasonic fields can push and levitate particles, heat up materials, induce contactless tactile stimuli, or affect the blood-brain barrier. Current phased-arrays can create dynamic amplitude patterns, but their quality may be insufficient due to the limited density of emitters. On the other hand, passive modulators can provide high quality, but only static patterns can be generated. Here, we show and evaluate how the average of multiple time-multiplexed amplitude fields improves the resolution of the obtained patterns when compared with the traditional single-emission method. We optimize the non-linear problem of decomposing a target amplitude field into multiple fields considering the limitations of the phased-array. The presented technique improves the quality for existing setups without modifying the equipment, having the potential to improve bio-printing, haptic devices, or ultrasonic medical treatments.
Open Access
Enhancing user experience in immersive virtual environments: advances in multiple object selection and affective interaction
(2025) Elizondo Martínez, Sonia; Marzo Pérez, Asier; Ortiz Nicolás, Amalia; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Los Entornos Virtuales Inmersivos (EVI) se utilizan para el entretenimiento, la educación, la atención sanitaria y la colaboración remota. Los EVI permiten a los usuarios participar e interactuar con contenido digital tridimensional de manera segura, consistente y controlada. Tres aspectos relevantes para lograr interacciones adecuadas entre los usuarios y los EVI son: 1) diseñar técnicas de interacción semejantes a las acciones del mundo real; 2) integrar tanto capacidades técnicas como emocionales; y 3) realizar evaluaciones exhaustivas de la experiencia de usuario para permitir una mejora constante de las capacidades de los EVI. Esta tesis doctoral ofrece una introducción detallada a los tres aspectos mencionados anteriormente: las técnicas de interacción (con un enfoque en la selección); el campo de la Computación Afectiva y cómo puede mejorar la experiencia de usuario en los EVIs; y los métodos implícitos y explícitos para evaluar tanto necesidades técnicas como emocionales con el fin de lograr una experiencia de usuario completa. Esta tesis también destaca las actuales limitaciones en la implementación de estos aspectos en los entornos virtuales y propone una nueva técnica de selección multiobjeto para los EVIs, así como un marco de diseño para guiar el desarrollo de EVIs con capacidades emocionales.
Embargo
EOLO, a wind energy forecaster based on public information and automatic learning for the Spanish Electricity Markets
(Elsevier, 2024-05-31) Prieto-Herráez, Diego; Martínez-Lastras, Saray; Frías Paredes, Laura; Asensio, María Isabel; González-Aguilera, Diego; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
For the correct operation of the electricity system, producers must provide an estimate of the energy they are going to discharge into the system, and they must face financial penalties if their forecasts are wrong. This is especially difficult in the case of renewable energies, and in particular wind energy because of its variability and intermittency. The tool proposed allows, in a first step, to improve the prediction of wind energy to be produced and, in a second step, to optimize the offer to be presented to the electricity market, so that the overall economic performance can be improved. This tool is based on the use of public information and automatic learning and has been evaluated on a set of 30 wind farms in Spain, using their historical production data. The results indicate improvements in both the accuracy of the energy estimation and the profit obtained from the energy sold.
Open Access
Experimental investigation of the particle oscillation instability in a single-axis acoustic levitator
(AIP Publishing, 2019) Brizzotti Andrade, Marco Aurélio; Polychronopoulos, Spyros; Memoli, Gianluca; Marzo Pérez, Asier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Single-axis acoustic levitators are employed in biomedicine, chemistry and physics experiments due to their ability to trap in mid-air objects of a wide range of materials and sizes. Although this type of levitator has been studied for decades, there are effects that are not well understood. One of these effects is the particle oscillation instability, in which the levitating particle starts to oscillate with increasing amplitude until it is ejected out of the levitator. Most of the operations performed with acoustic levitation require high accuracy regarding the positioning of the particle, thus a lack of stability severely hinders the experiments. In this paper, we present an experimental setup that consists of a single-axis levitator, a mechanized stage to control the separation between the emitter and the reflector, a scale to measure the radiation force and a high-speed camera. We experimentally investigate the effect of the distance between the emitter and the reflector on the apparatus resonant frequency and on levitation stability. In accordance with previous theoretical studies, three types of levitation behavior were experimentally identified: stable levitation, oscillation of constant amplitude and unstable oscillation. We also show that the type of levitation behavior can be controlled by changing the distance between the emitter and the reflector.
Open Access
Exploring crowdshippers' behavior and preferences: intertwining urban distribution and people mobility
(Elsevier, 2025-05-14) García Herrera, Alisson Maurinne; Serrano Hernández, Adrián; Faulín Fajardo, Javier; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
Collaborative economy companies in the transport field have been a disruptive force in the urban mobility landscape around the world during the last decade 2010-2020. Crowdshipping has emerged as a collaborative economy option promoting improved utilization of currently underutilized transportation capacity, thereby reducing transportation costs and emissions. This article aims to analyze and synthesize existing research on the impact of the crowdshipper (individuals responsible for collecting and delivering the product) behavior on the system and the factors that drive his or her willingness to participate, to identify best practices and opportunities to enhance business analytics, decision-making, and model efficiency in this emerging area.
Open Access
Geometric multigrid methods for Darcy–Forchheimer flow in fractured porous media
(Elsevier, 2019) Arrarás Ventura, Andrés; Gaspar, F. J.; Portero Egea, Laura; Rodrigo, C.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
In this paper, we present a monolithic multigrid method for the efficient solution of flow problems in fractured porous media. Specifically, we consider a mixed-dimensional model which couples Darcy flow in the porous matrix with Forchheimer flow within the fractures. A suitable finite volume discretization permits to reduce the coupled problem to a system of nonlinear equations with a saddle point structure. In order to solve this system, we propose a full approximation scheme (FAS) multigrid solver that appropriately deals with the mixed-dimensional nature of the problem by using mixed-dimensional smoothing and inter-grid transfer operators. Numerical experiments show that the proposed multigrid method is robust with respect to the fracture permeability, the Forchheimer coefficient and the mesh size. The case of several possibly intersecting fractures in a heterogeneous porous medium is also discussed.
Open Access
Grape stems as preservative in Tempranillo wine
(2022) Pires Nogueira, Danielle; Jiménez Moreno, Nerea; Esparza Catalán, Irene; Moler Cuiral, José Antonio; Ancín Azpilicueta, Carmen; Zientziak; Estatistika, Informatika eta Matematika; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Estadística, Informática y Matemáticas
SO2 is the most widely used preservative in the wine industry. However, there are several drawbacks related with the use of SO2 in wine, such as, its toxicity and the unpleasant odor in case of excess [1]. These reasons justify the importance of searching alternatives to reduce or eliminate this preservative from wine. Polyphenol rich extracts from agri-food industry by-products have been studied as a replacement for their high antioxidant activity, and positive results reported [2]. The grapes stems are discarded early on in the winemaking process, in spite of containing large amounts of polyphenolic compounds with antioxidant activity. The aim of this work was to determine whether the ground stem and its extract had the potential to totally or partially replace SO2 in wine.