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- 저자 : Guerreiro (검색결과 31 건)
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A Sensorless PMDC Motor Speed Controller with a Logical Overcurrent Protection
Guerreiro, M.G.,Foito, D.,Cordeiro, A. The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.3
A method to control the speed or the torque of a permanent-magnet direct current motor is presented. The rotor speed and the external torque estimation are simultaneously provided by appropriate observers. The sensorless control scheme is based on current measurement and switching states of power devices. The observers performances are dependent on the accurate machine parameters knowledge. Sliding mode control approach was adopted for drive control, providing the suitable switching states to the chopper power devices. Despite the predictable chattering, a convenient first order switching function was considered enough to define the sliding surface and to correspond with the desired control specifications and drive performance. The experimental implementation was supported on a single dsPIC and the controller includes a logic overcurrent protection.
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Guerreiro, Marisa M.,Serranheira, Florentino,Cruz, Eduardo B.,Sousa-Uva, Antonio Occupational Safety and Health Research Institute 2020 Safety and health at work Vol.11 No.4
Background: Assembly lines work is frequently associated to work-related upper limb musculoskeletal disorders. The related disability and absenteeism make it important to implement efficient health surveillance systems. The main objective of this study was to identify self-reported variables that can determine work-related upper limb musculoskeletal symptoms-discomfort/pain-during a 6-month follow-up. Methods: This was a prospective study with a 6-month follow-up period, performed in an assembly line. Upper limb musculoskeletal discomfort/pain was assessed through the presence of self-reported symptoms. Uni- and multivariate logistic regression analyses were used to evaluate which self-reported variables were associated to upper limb symptoms after 6 months at the present and to upper limbs symptoms in the past month. Results: Of the 200 workers at baseline, 145 replied to the survey after 6 months. For both outcomes, "having upper limb symptoms during the previous 6 months" and "education" were possible predictors. Conclusion: Our results suggest that having previous upper limb symptoms was related to its maintenance after 6 months, sustaining it as a specific determinant. It can be a hypothesis that this population had mainly workers with chronic symptoms, although our results give only limited support to self-reported indicators as determinants for upper limb symptoms. Nevertheless, the development of an efficient health surveillance system for high demanding jobs should implicate self-reported indicators, but also clinical and work conditions assessment should be accounted on the future.
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Is Price Dynamics Homogeneous Across Eurozone Countries?
( David Guerreiro ),( Marc Joets ),( Valerie Mignon ) 세종대학교 경제통합연구소(구 세종대학교 국제경제연구소) 2012 Journal of Economic Integration Vol.27 No.4
The aim of this paper is to investigate whether price dynamics is homogeneous across the Eurozone countries. Relying on monthly data over the January 1970~July 2011 period, we test for the absolute purchasing power parity (PPP) hypothesis through the implementation of second and third-generation panel unit root and cointegration tests. Our results show that price dynamics are heterogeneous depending on both the time period and the considered group of countries. More specifically, while PPP is validated for the core Economic Monetary Union (EMU) countries, this hypothesis does not hold for Northern peripheral economies. Turning to the Southern countries, PPP is observed only before the launch of the euro.
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Rui Azevedo Guerreiro,Paula Fazendas,Ana Rita Pereira,Ana Marques,João Pais,Sofia Alegria,Kisa Hyde Congo,Ana Catarina Gomes,João Carvalho,Gonçalo Morgado,Inês Cruz,Ana Rita Almeida,Isabel João,Hélder 한국심초음파학회 2020 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.28 No.2
BACKGROUND: Stress echocardiography has a 72%–85% sensitivity and an 80%–95% specificity. In this study, we characterized patients who received a false-positive stress echocardiogram result. METHODS: A total of 5,256 patients underwent a stress echocardiogram (induced by exercise, dobutamine, or dipyridamole) between 2009 to 2018, and 405 patients (7.7%) received a positive result. Among the positive patients, 300 underwent coronary angiography within 12 months, and these patients were included in this study (mean age = 64.9 ± 9.4 years, 230 men [76.7%]). Coronary artery disease was diagnosed by stenosis ≥50% in any epicardial coronary artery. Clinical and echocardiographic variables were compared between patients with true- and false-positive stress echocardiogram results. RESULTS: Seventy-two patients (24%) had a false-positive stress echocardiogram, with similar rates across stressor types (p = 0.574). Patients with false positives were less frequently men (63.9% vs. 80.7%, p = 0.003), had lower diabetes mellitus prevalence (15.3% vs. 45.6%, p = 0.001), were similar to true positive patients with regard to body-mass index, arterial hypertension prevalence, hyperlipidemia and smoking, and had lower pre-test probability of coronary artery disease (23% vs. 32%, p = 0.016). The wall motion score index (WMSI) was higher in the true-positive stress group, and wall motion abnormalities were more frequent in the apical segments (70.5% vs. 56.7%, p = 0.034). In a multivariable predictive model, men (odds ratio [OR] = 2.994), diabetes (OR = 5.440), and peak WMSI (OR = 10.690) were associated with a true-positive result. CONCLUSIONS: Twenty-four percent of our study population received a false-positive stress echocardiogram result, with similar rates across stressor types. Patients with true-positive stress echocardiogram results are more likely to be men, diabetic, and have a high peak WMSI.
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A Sensorless PMDC Motor Speed Controller with a Logical Overcurrent Protection
M. G. Guerreiro,D. Foito,A. Cordeiro 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.3
A method to control the speed or the torque of a permanent-magnet direct current motor is presented. The rotor speed and the external torque estimation are simultaneously provided by appropriate observers. The sensorless control scheme is based on current measurement and switching states of power devices. The observers performances are dependent on the accurate machine parameters knowledge. Sliding mode control approach was adopted for drive control, providing the suitable switching states to the chopper power devices. Despite the predictable chattering, a convenient first order switching function was considered enough to define the sliding surface and to correspond with the desired control specifications and drive performance. The experimental implementation was supported on a single dsPIC and the controller includes a logic overcurrent protection.
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THE PERCEPTION OF TRUST IN PERSONALIZED VIDEO NEWS GENERATED BY ARTIFICIAL INTELLIGENCE
Felipe Breviglieri,Jo?o Guerreiro,Sandra Loureiro 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07
As the use of artificial intelligence (AI) grows, so do the questions regarding this new technology and its potential uses. Among the various possibilities and employment that could be offered by AI is personalized news technology. Nowadays, it is already possible to produce journalistic content through AI (Carlson, 2014; Graefe & Haim, 2018). Digital storytelling has become a reality through automated journalism powered by AI (Caswell & D?rr, 2018; Galily, 2018; Linden, 2017; Thorne, 2020). “Artificial intelligence applies advanced analysis and logic-based techniques, including machine learning, to interpret events, support and automate decisions, and take actions” (Gartner Group, 2019). In personalized news technology, algorithms are responsible for selecting content and sorting it according to the personalization criteria (Powers, 2017). So far, AI has been studied in different fields with distinct research focuses (Loureiro et al., 2021). Studies of news-personalization technologies have mainly focused on research engines and filtering mechanisms (Darvishy et al., 2020; Haim et al., 2017; Manoharan & Senthilkumar, 2020). Few studies examine news aggregators (Haim et al., 2018; Kwak et al., 2021) and the effects of news personalization on audiences (Merten, 2021; Swart, 2021; Thurman et al., 2019), thus demanding further research. AI is an imminent reality for the future, reshaping the news media (Brennen et al., 2022; Linden, 2017; Thorne, 2020). Hence, it is still necessary to investigate the impacts that this technology potentially offers to users. Therefore, the current study seeks to respond to this need to deepen research into the area of news personalization through AI, by analyzing the response of audiences toward current and future technological tendencies. The main aim of this research is to investigate the levels of trust that users have in AI-generated personalized video news.
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SMART WELLNESS ROBOTS: HOW SERVICE ROBOTS AFFECT CONSUMER WELL-BEING
Sandra Loureiro,Jo?o Guerreiro 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07
Technologies, such as Artificial Intelligence (AI) and robotics are emerging as a new way to improve services, readjusting and impacting all business industries and relationships among people (Loureiro et al., 2021; Makridakis, 2017; Mingotto et al., 2020). The hospitality industry is no exception to this (Mingotto et al., 2020) since a quick growth in the use of robots and AI in this industry has registered a turnover of 249 million U.S. dollars (International Federation of Robots, 2021). However, very few of the existing studies highlight the customers’ perspective and sentiments on service robots (Luo et al., 2021) or the robot-human interactions/ customer service experience (Choi et al., 2021). Thus, further studies in the enhancement of human well-being through transhumanistic technologies, close relationship marketing capabilities, and the evolution of the engagement process between humans and AI-enabled machines are necessary (Loureiro et al., 2021). This research intends to understand how different types of robots influence customers’ perception of the service provided. Therefore, the following research questions are proposed; Can humans develop feelings of identification with a service robot? Can the identification that customers perceive between themselves, and service robots be strong enough to influence the creation of a close relationship between both parties? What are the features of service robots that heighten customer well-being?
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Torres Fernanda Ferrari Esteves,Guerreiro-Tanomaru Juliane Maria,Chavez-Andrade Gisselle Moraima,Pinto Jader Camilo,Berbert Fábio Luiz Camargo Villela,Tanomaru-Filho Mario 대한치과보존학회 2020 Restorative Dentistry & Endodontics Vol.45 No.2
Objectives: This study compared the flow and filling of several retrograde filling materials using new different test models. Materials and Methods: Glass plates were manufactured with a central cavity and 4 grooves in the horizontal and vertical directions. Grooves with the dimensions used in the previous study (1 × 1 × 2 mm; length, width, and height respectively) were compared with grooves measuring 1 × 1 × 1 and 1 × 2 × 1 mm. Biodentine, intermediate restorative material (IRM), and mineral trioxide aggregate (MTA) were evaluated. Each material was placed in the central cavity, and then another glass plate and a metal weight were placed over the cement. The glass plate/material set was scanned using micro-computed tomography. Flow was calculated by linear measurements in the grooves. Central filling was calculated in the central cavity (mm3 ) and lateral filling was measured up to 2 mm from the central cavity. Results: Biodentine presented the least flow and better filling than IRM when evaluated in the 1 × 1 × 2 model. In a comparison of the test models, MTA had the most flow in the 1 × 1 × 2 model. All materials had lower lateral filling when the 1 × 1 × 2 model was used. Conclusions: Flow and filling were affected by the size of the test models. Higher grooves and materials with greater flow resulted in lower filling capacity. The test model measuring 1 × 1 × 2 mm showed a better ability to differentiate among the materials.
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