1,720,958 research outputs found
Stress and Mental Workload Monitoring in Pilots Using a Physiological Signals Approach
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
Unveiling Mental Workload via PPG: Morphological and Respiratory Feature–Driven Machine Learning Classification
No full textThe integration of the latest artificial intelligence (AI)-based technologies in high-risk operational sectors requires, as an essential prerequisite, the availability of reliable feedback on the mental workload (MWL) perceived by the operator. In this context, the analysis of variations in physiological signals remains one of the most promising and scalable approaches for estimating MWL in varied application scenarios. This study proposes the development of a predictive model solely based on the analysis of the photoplethysmographic (PPG) signal, a technology that is easily integrable into wearable systems and already widely used in clinical and consumer applications. In addition to the traditional variables associated with heart rate variability (HRV), which have been explored in previous literature, this work introduces an innovative analysis of morphological parameters of the individual pulse wave, which have not been previously investigated in the context of MWL. Furthermore, by reconstructing the respiratory contribution from the PPG signal, additional features related to respiratory variability were derived. The machine learning models were trained using the publicly available MAUS dataset, which includes recordings from 22 subjects exposed to controlled cognitive workload conditions through the N-back test. The obtained results, with an accuracy of 81.5% in the binary classification between low and high MWL levels, confirm the effectiveness of the proposed approach and highlight its potential for continuous, non-invasive monitoring of mental workload through a single wearable sensor
ECG, Respiration, fNIRS, and Eye Tracking for Stress and Mental Workload Monitoring in Human-Machine Interaction
Full text linkAdvanced human-machine interaction (AHMI) is a key concept in human factors and ergonomics (HFE), focusing on how individuals interact with systems to perform tasks efficiently. As AHMI becomes more integrated into fields such as Industry 4.0, aviation, automotive, and clinical applications, users face increasing complexity, leading to elevated mental workload (MWL) and stress. These factors can impair performance and cause accidents, emphasizing the need for AHMI systems capable of real-time monitoring of cognitive load and stress levels. This paper investigates the relationship between stress, MWL, and four physiological signals - electrocardiogram (ECG), respiration, functional near-infrared spectroscopy (fNIRS), and eye tracking - combined with a tailored Self-Assessment Questionnaire (SAQ), specifically designed for industrial applications. A study involving 20 participants was conducted using the Stroop, Visual, Auditory, and Dual N-Back tasks. During the study, 83 features were extracted from the physiological signals and linked to this four-level ratings SAQ of perceived stress and MWL. Statistical analysis using Kruskal-Wallis and Mann-Whitney tests assessed the ability of these features to differentiate stress and MWL levels. Over 50% of the features reliably distinguished between cognitive states, particularly in identifying relaxed versus altered conditions. Respiration, fNIRS, and eye movement signals provided higher granularity in differentiating multiple altered cognitive states, suggesting their potential for precise monitoring in AHMI systems. These findings underscore the value of physiological monitoring in AHMI systems, which can enhance user performance and safety by enabling adaptive interfaces tailored to real-time cognitive states, supporting future industrial applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Software-based solutions for the optimization of a building electric bill using integrated PV and storage systems: a case study
No full textGreen energies are establishing themselves as a training sector in the last decade, enabling economic and technological opportunities still to be investigated. This article proposes a solution for energy management, merging photovoltaics and storage systems, focusing on the city urban environment and taking as the main case study the typical multi-storey building characterized by high density of households. The proposed solution optimizes the cost of the electrical bill using a predictive algorithm, stem from an economical analysis based on the production and consumption of the system
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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