1,720,982 research outputs found
Wearable Brain-Computer Interface Instrumentation for Robot-Based Rehabilitation by Augmented Reality
Full text linkAn instrument for remote control of the robot by wearable brain-computer interface (BCI) is proposed for rehabilitating children with attention-deficit/hyperactivity disorder (ADHD). Augmented reality (AR) glasses generate flickering stimuli, and a single-channel electroencephalographic BCI detects the elicited steady-state visual evoked potentials (SSVEPs). This allows benefiting from the SSVEP robustness by leaving available the view of robot movements. Together with the lack of training, a single channel maximizes the device's wearability, fundamental for the acceptance by ADHD children. Effectively controlling the movements of a robot through a new channel enhances rehabilitation engagement and effectiveness. A case study at an accredited rehabilitation center on ten healthy adult subjects highlighted an average accuracy higher than 83%, with information transfer rate (ITR) up to 39 b/min. Preliminary further tests on four ADHD patients between six- and eight-years old provided highly positive feedback on device acceptance and attentional performance
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
Broadband Power Line Communication in Railway Traction Lines: A Survey
No full textPower line communication (PLC) is a technology that exploits existing electrical transmission and distribution networks as guiding structures for electromagnetic signal propagation. This facilitates low-rate data transmission for signaling and control operations. As the demand in terms of data rate has greatly increased in the last years, the attention paid to broadband PLC (BPLC) has also greatly increased. This concept also extended to railways as broadband traction power line communication (BTPLC), aiming to offer railway operators an alternative data network in areas where other technologies are lacking. However, BTPLC implementation faces challenges due to varying operating scenarios like urban, rural, and galleries. Hence, ensuring coverage and service continuity demands the suitable characterization of the communication channel. In this regard, the scientific literature, which is an indicator of the body of knowledge related to BTPLC systems, is definitely poor if compared to that addressed to BPLC systems installed on the electrical transmission and distribution network. The relative papers dealing with BTPLC systems and focusing on the characterization of the communication channel show some theoretical approaches and, rarely, measurements guidelines and experimental results. In addition, to the best of the author’s knowledge, there are no surveys that comprehensively address these aspects. To compensate for this lack of information, a survey of the state of the art concerning BTPLC systems and the measurement methods that assist their installation, assessment, and maintenance is presented. The primary goal is to provide the interested readers with a thorough understanding of the matter and identify the current research gaps, in order to drive future research towards the most significant issues
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
A method for the metrological characterization of eye- and head-tracking interfaces for human–machine interaction through eXtended Reality head-mounted displays
No full textGiven the increasing interest in novel and powerful Human–Machine Interaction modalities, as well as the role that eXtended Reality (XR) plays in the contemporary societal framework, this paper proposes a metrologically sound method for the experimental characterization of innovative XR-based Human–Machine Interfaces (HMIs). The aim is to thoroughly analyze the interaction between users and the digital content rendered within the XR environment, focusing on two hands-free HMIs, namely eye- and head-tracking. Starting from the acquisition of eye gaze and head pose, the proposed method encompasses the analysis of metrics such as horizontal and vertical offsets, and Euclidean distance with respect to digital reference points. From these metrics, the proposed method yields a novel figure of merit, named Maximum Number, providing insight into the optimal configuration of the XR content to maximize the information transfer. As a case study, but without loss of generalization, the XR head-mounted display Microsoft HoloLens 2 is considered. Experimental findings, derived from a campaign involving 16 subjects, contribute to a deeper understanding of the accuracy and precision in content selection, along with the number of objects that can be accommodated within the XR environment for the developed HMIs. This addresses a critical gap in current knowledge and offers valuable insights, compensating for the lack of information available in technical specifications, paving the way for the development of reliable hands-free applications in contexts with stringent requirements, such as industry or healthcare inspection tasks
Experimental procedure for metrological characterization of AR-based eye-tracking interfaces
No full textGiven the increasing demand for hands-free input interfaces within Augmented Reality (AR) applications, this paper addresses an experimental characterization of eye-tracking technology as an input mechanism for AR Head-Mounted Displays (HMDs). To this end, an AR application was developed with the aim of simulating a real-world application scenario. In this scenario, a set of objects is rendered within the scene so that each object can associated with a distinct command to be executed. The purpose of the developed application is to assess the capability of the input interface in accurately recognizing the objects selected through ocular movements. This evaluation also encompasses the interface performance in detecting the user-declared point of gaze, thereby quantifying the error between the user-reported focus and the interface perceptual outcomes. As a case study, without loss of generalization, the AR HMD Microsoft HoloLens 2 is considered. Eight different subjects were involved in the experimental campaign. The obtained experimental results showcase satisfactory performance with HoloLens 2. This paves the way for more robust development of eye-tracking-based applications, even in scenarios with stringent requirements
AR-based monitoring of instrumentation in the operating room
Full text linkThis paper proposes an augmented reality (AR)-based system for monitoring patient's vitals in the operating room (OR) is proposed. An optical see-through (OST) headset, worn by the anesthetist or by the OR nurses, shows in real-time the patient's vitals acquired from the electromedical equipment available in the OR. A dedicated application was developed to allow a hands-free fruition of the AR content. Experimental tests were carried out acquiring the vital parameters from two pieces of equipment typically available in the OR, namely a ventilator and a monitor. The experimental assessment of the transmission error rate and of latency demonstrated the reliability of the proposed AR-based monitoring system
Performance enhancement of wearable instrumentation for AR-based SSVEP BCI
No full textThis work addresses an innovative processing strategy to improve the classification of Steady-State Visually Evoked Potentials (SSVEPs). This strategy resorts to the combined use of fast Fourier transform and Canonical Correlation Analysis in time domain, and manages to outperform by over 5% previous results obtained for highly wearable, single-channel Brain–Computer Interfaces. In fact, a classification accuracy of 90% is reached with only 2-s time response. Then, the proposed algorithm is employed for an experimental characterization of three different Augmented Reality (AR) devices (namely, Microsoft Hololens I, Epson Moverio BT-350, and Oculus Rift S). These devices are used to generate the flickering stimuli necessary to the SSVEP induction. Also, in the three pieces of instrumentation under test, the number of simultaneous visual stimuli was increased with respect to the state-of-art solutions. The aim of the experimental characterization was to evaluate the influence of different AR technologies on the elicitation of user's SSVEPs. Classification accuracy, time response, and information transfer rate were used as figures of merit on nine volunteers for each piece of instrumentation. Experimental results show that choosing an adequate AR headset is crucial for obtaining satisfying performance: in fact, it can be observed that the classification accuracy obtained with Microsoft Hololens is about 20% greater than Epson Moverio one
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