IPT - Ci2 - Artigos em Revistas Científicas
Permanent URI for this collection
Browse
Browsing IPT - Ci2 - Artigos em Revistas Científicas by Issue Date
Now showing 1 - 10 of 16
Results Per Page
Sort Options
- Performance Comparison of Grid-Faulty Control Schemes for Inverter-Based Industrial MicrogridsPublication . Camacho Santiago, Antonio; Castilla, Miguel; Canziani, Franco; Moreira, Carlos; Coelho, Paulo; Gomes, Mário; Mercado, PedroSeveral control schemes specifically designed to operate inverter-based industrial microgrids during voltage sags have been recently proposed. This paper first classifies these control schemes in three categories and then performs a comparative analysis of them. Representative control schemes of each category are selected, described and used to identify the main features and performance of the considered category. The comparison is based on the evaluation of several indexes, which measure the power quality of the installation and utility grid during voltage sags, including voltage regulation, reactive current injection and transient response. The paper includes selected simulation results from a 500 kVA industrial microgrid to validate the expected features of the considered control schemes. Finally, in view of the obtained results, the paper proposes an alternative solution to cope with voltage sags, which includes the use of a static compensator in parallel with the microgrid. The novelty of this proposal is the suitable selection of the control schemes for both the microgrid and the static compensator. The superior performance of the proposal is confirmed by the analysis of the quality indexes. Its practical limitations are also revealed, showing that the topic studied in this paper is still open for further research.
- Audio Features for Music Emotion Recognition: a SurveyPublication . Panda, Renato; Malheiro, Ricardo; Paiva, Rui PedroThe design of meaningful audio features is a key need to advance the state-of-the-art in Music Emotion Recognition (MER). This work presents a survey on the existing emotionally-relevant computational audio features, supported by the music psychology literature on the relations between eight musical dimensions (melody, harmony, rhythm, dynamics, tone color, expressivity, texture and form) and specific emotions. Based on this review, current gaps and needs are identified and strategies for future research on feature engineering for MER are proposed, namely ideas for computational audio features that capture elements of musical form, texture and expressivity that should be further researched. Finally, although the focus of this article is on classical feature engineering methodologies (based on handcrafted features), perspectives on deep learning-based approaches are discussed.
- Participation of students in the project Valorbio: A case study to accelerate the implementation of sustainability principles in the curriculumPublication . Mateus, D. M. R.; Pinho, Henrique J. O.; Nogueira, Isabel; Rosa, Manuel; Cartaxo, Marco; Nunes, ValentimPurpose – The present work describes the case of the Valorbio research project, in which students of different high-level programs were involved in the experimental work and in the dissemination of results in collaboration with the research team. Design/methodology/approach – The inclusion in higher education curricula of content related to the sustainable development should be a preferred mechanism for the dissemination of good practices of sustainability. Another equally important way to achieve this is to involve students in research projects that seek solutions to the societal challenges related to sustainable growth. The Valorbio project aims to meet the needs for treating and reusing wastewater and solid waste. Its main goal was the development of modular systems for wastewater treatment based on constructed wetlands,exploring the possibility of the treatment systems being composed of solid waste and by-products from significant industrial sectors. Findings – The students’ contributionto the research workwas relevant, and simultaneously allowedthem to acquire skills on sustainable development. Additionally, the students contributed to the dissemination of the results. The Valorbio project can thus be considered a successful application of the concept of project-based learning,as a way to include sustainability issues content in the higher education curricula. Originality/value – The applied experimental work had an original approach regarding the equipment design, the waste materials valuation, as well as the integration of waste treatment processes in the circular economy paradigm.This paper is the first reported project-based learning experience involving students of short-cycle technical-professional programs in partnership with first and second-level students and a research team.
- Design of a Mobile Augmented Reality Platform with Game-Based Learning PurposesPublication . Costa, Maria Cristina; Manso, António; Patrício, JoãoAugmented reality (AR) is an emergent technology that overlays virtual objects into the real environment. Lately, AR is gaining prominence in education because of its increasing affordability through computers or mobile technologies. In addition, research sustaining the benefits of AR to promote student’s engagement to learn is increasing every day. However, the literature identifies lack of studies about the use of AR in education, namely, studies focused on the development of AR games designed over specific learning objectives (game-based learning). This paper presents a mobile augmented reality platform with learning purposes. The platform includes a mobile application that consists of a location-based game targeted to promote learning about the universe. Furthermore, it includes a back-office that allows teachers to introduce information about celestial bodies and also develop a set of multiple-choice questions to assess student’s learning about the subject matters they teach. The mobile application provides the users with physical movement and social interaction in the real world, while playing the game and for this reason it is included in the pervasive games’ paradigm. Besides engaging the students to play the game, we argue that this platform may be used as a resource to be implemented in informal and formal learning environments.
- Evaluation of solid waste stratified mixtures as constructed wetland fillers under different operation modesPublication . Mateus, D.M.R.; Pinho, Henrique J. O.Based on the strategy that all processes can and should be modified to contribute to a circular economy, this work evaluates the recovery of waste solids as filler material in Constructed Wetlands (CWs) used for wastewater treatment. Five sets of lab-scale CWs were assembled with mixtures of five waste solids and operated to evaluate the removal of chemical oxygen demand (COD) and nutrients from urban and industrial-types of wastewater. The adaptation and growth of the macrophyte Phragmites australis in the mixed-filler CWs was also monitored. Although all evaluated waste solids showed to be acceptable substrates for macrophyte development and wastewater treatment, CWs assembled with mixtures of limestone waste and coal slag showed the best plant growth indicators and wastewater treatment efficiencies. The CWs assembled with mixtures of limestone waste and clay brick fragments or cork granulates showed to be suitable alternatives. With exception for CWs filled with mixtures of limestone and snail shells, pollutant removal efficiencies up to 95%, 86% and 83% were obtained respectively for COD, total phosphorous and total nitrogen, depending on the type of wastewater and mode of operation. Removal efficiencies were not significantly affected by increased hydraulic rate. The CWs can be operated to a hydraulic loading rate of 0.056 m/d, which corresponds to a retention time of 1.5 days. The valorisation of solid waste as a filler can contribute to CWs closely participating in the creation of circular flows for the reuse of waste solids.
- Telehealth monitoring of a hypertensive elderly patient with the new VITASENIOR-MT system: a case studyPublication . Pereira, Telmo; Pires, Gabriel; Jorge, Dário; Mendes, DiogoTelehealth technologies providing remote monitoring of health parameters are a promising approach for the management of arterial hypertension in the elderly. The VITASENIOR-MT platform was developed as a telehealth solution designed to contribute to improve the health condition and quality of life, promoting safe and independent living of the old adult. It is an 'internet-of-things'-based solution relying on the interaction of the old adult with a TV-set to record biometric parameters and to receive warning and recommendations related to health and environmental sensor recordings. We present a pilot study with a male hypertensive patient, aged 81 years old, under anti-hypertensive treatment, with epilepsy, arthritis and paroxistic atrial fibrillation as major comorbidities. The VITASENIOR-MT was installed at the patient's assisted-dwelling house and a remote follow-up was implemented for 2 months, monitoring daily blood pressure and heart rate, as well as weight and indoor environmental parameters.
- Sustainable Production of Reclaimed Water by Constructed Wetlands for Combined Irrigation and Microalgae Cultivation ApplicationsPublication . Pinho, Henrique J. O.; Mateus, D. M. R.Considering the increasing pressure on freshwater resources due to the constant increase in water consumption and insufficient wastewater control and treatment, recovering waste water is a path to overcoming water scarcity. The present work describes the potential of reusing treated wastewater (reclaimed water) for irrigation and production of microalgae biomass in an integrated way, through experimental evaluation of plant and microalgae growth, and creation of an application model. First, two parallel experiments were conducted to evaluate the use of reclaimed water produced by a constructed wetland filled with a mix of solid waste: the irrigation of a set of small pots filled with soil and planted with Tagetes patula L., and the cultivation of microalgae Chlorella sp.and a mixed microalgae population with predominant species of the genus Scenedesmus sp. in shaken flasks and tubular bubble column photobioreactors. Results indicated no negative effects of using the reclaimed water on the irrigated plants and in the cultivated microalgae. The growth indicators of plants irrigated with reclaimed water were not significantly different from plants irrigated with fertilized water. The growth indicators of the microalgae cultivated with reclaimed water are within the range of published data. Second, to apply the results to a case study, the seasonal variability of irrigation needs in an academic campus was used to propose a conceptual model for wastewater recovery. The simulation results of the model point to a positive combination of using reclaimed water for the irrigation of green spaces and microalgae production, supported by a water storage strategy. Water abstraction for irrigation purposes can be reduced by 89%, and 2074 kg dry weight microalgae biomass can be produced annually. Besides the need for future work to optimize the model and to add economical evaluation criteria, the model shows the potential to be applied to non-academic communities in the perspective of smarter and greener cities.
- A Usability Study on Widget Design for Selecting Boolean OperationsPublication . Chambel Lopes, Diogo; Mendes, Helena; Portal, Ricardo; Klerk, Rui de; Nogueira, Isabel; Lopes, Daniel SimõesApplying the correct set of Boolean operations is a fundamental task in constructive solid geometry (CSG), which is a staple in automated manufacturing systems. Although textual buttons and icons are the most common interfaces to apply such operations, these require an unnecessary cognitive load that hampers the solid modeling process. This study presents VennPad, a novel CSG widget that gathers all Boolean operations under the same user interface control element and is represented as a two-set Venn diagram. Contrary to conventional CSG widgets, VennPad supports a graphical interface that gives simultaneous access to several types of Boolean operations (intersection, union, difference, symmetric difference and split). A usability study was conducted to ascertain whether VennPad is a more natural interface compared to textual buttons and icon-based widgets for different solid modeling tasks. VennPad proved to be an effective interface to perform Boolean operations. Qualitative feedback places VennPad as the preferred interface, but efficiency results are operation dependent, thus, opening the way to new design iterations.
- Remote Monitoring of Energy-autonomous Constructed WetlandsPublication . Lopes, Simão; Barros, F.M.; Ferreira, Carlos; Mateus, D. M. R.; Matos, Pedro; Neves, Pedro; Pinho, Henrique J. O.Constructed Wetlands systems (CW) are nature-based and sustainable technology for treating wastewater, contributing to the management and protection of freshwater resources. Moreover, CW can contribute to valorizing waste materials, producing reclaimed water for diverse applications, and producing plant biomass that can be material and energetically valorized. Because CW efficiency depends on several mechanisms such as physical, chemical, and biological, its real-time monitoring is essential to provide a better use of this technology. This work describes a smart framework for monitoring CW based on IoT devices and sensors, and data science tools providing real-time processing of gathered water quality parameters and environmental variables. Furthermore, the framework manages renewable energy sources to provide the required energy for CW operation and monitoring. Data collected from the sensor network show significant daily variations in water quality parameters. The future processing of these data can provide the development of models to improve the efficiency of the CW.
- Wastewater Electrolysis for Hydrogen ProductionPublication . Cartaxo, Marco; Fernandes, José; Gomes, Mário; Pinho, Henrique J. O.; Nunes, Valentim; Coelho, PauloDue to its highest gravimetric energy density, H2 has been regarded as the preferred clean-energy carrier, with potentially environmentally-friendly production through the solar-assisted WS. Since human activities generate enormous amounts of WW, H2 production from this new resource has gained attention as an emergent technology. This paper addresses the most relevant and current aspects of H2 production from WWEL, and electricity generation from RES. In this sense, the state of art of H2 production, especially from WS, is presented here, as well as the main approaches to electricity generation from RES, with the greatest potential for viability. A new approach on this matter, which is part of the work that is being developed by the authors of this study, was also herein presented.