1,721,060 research outputs found
A Clustered Federated Learning Approach for Estimating the Quality of Experience of Web Users
No full textIn this paper, we present FedCLWAvg, a novel clustered Federated Learning (FL) approach for estimating the Quality of Experience (QoE) of Web users. FedCLWAvg performs clustering on the weights of the trained local models (CLW stands for clustered weights) to identify users with similar data distribution. In the context of QoE modelling, the hypothesis is that personal differences (in terms of perceived QoE for the same stimuli) between groups of users are reflected in different weights of the trained local models. Then, each identified cluster learns its own model using the FedAvg algorithm. To validate our approach, we used the Web QoE dataset including the subjective quality of 3,400 Web browsing sessions identified by the measurement of 9 Web session features. Experimental results have shown that FedCLWAvg achieved greater QoE estimation performance than the classical FedAvg algorithm in terms of mean accuracy and recall, F1-score, and precision computed for the single quality scores
Will virtual reality transform online synchronous learning? Evidence from a quality of experience subjective assessment
No full textIn this article, we preliminarily discuss the limitations of current video conferencing platforms in online synchronous learning. Research has shown that while the involved technologies are appropriate for collaborative video calls, they often fail to replicate the rich nature of face-to-face interactions among students and between students and professors, by constraining them to a grid of faces on screens and limiting the natural flows of conversation and nonverbal communication. We believe that a potential solution to this issue could be adopting virtual reality (VR) technologies in online synchronous teaching. To test our assumption, we developed a novel subjective assessment involving 44 electronics engineering students who attended real lessons on Internet protocols. The taught content was included in the course program and the final exam; the professor made use of slides for teaching and a blackboard to explain some exercises. Two different learning approaches were used: VR-based online synchronous learning and video-based online synchronous learning. While the former consisted in wearing a headset and participating in a virtual classroom in front of the teacher’s avatar, the latter involved watching a 2-D video of the streamed lesson through a laptop and communicating through the microphone. The opinions collected from the students included several aspects, namely, overall quality of experience, immersion, interactivity, naturalness, usability, entertainment, comfort, side effects, interaction with the teacher and students, and ease of taking notes. Key findings from Welch’s t-test indicate the higher interactivity (p<0.05), naturalness (p<0.01), entertainment (p<0.01), and immersion (p<0.001) perceived by students for the VR-based learning experience than the video-based one. Increased immersion was the most significant aspect, as highlighted by the lowest p-value. On the other hand, the level of comfort was heavily penalized (p<0.001), and students were unable to take notes in the VR classroom environment easily. No significant difference (p>0.05) was achieved for the other considered metrics
Il benessere organizzativo. Presupposti teorici e verifica empirica di uno strumento per la prevenzione del disagi psico-sociale
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Towards the evaluation of the effects of ambient illumination and noise on quality of experience
Full text linkThe physical context, i.e., the characteristics of location and space where the multimedia service is consumed, may strongly influence the overall perceived Quality of Experience (QoE). In this paper, we investigate the effects of ambient illumination and noise on two multimedia consumption scenarios: watching a video on TV and reading a comic strip on tablet. To this aim, we organized an experiment considering different combinations of ambient illumination and introducing a disturbing noise. Then, we conducted a subjective quality assessment involving 20 people, who were asked to rate the perceived QoE using the 5-level Absolute Category Rating (ACR) quality scale and to express their emotions completing the Self-Assessment Manikin (SAM) questionnaire. The impact of illumination and noise on ACR ratings and SAM scores is evaluated computing the Multivariate Analysis of Variance (MANOVA). Finally, a QoE prediction model based on illumination and noise context factors is presented
How to evaluate Quality of Life
Full text linkIn medical terminology, it has become more and more common the use of the expression “Quality of Life” (QoL) to define a series of aspects that go beyond the traditional, clinical and “objective” evaluation of the medical intervention. The attention to QoL comes from the need to find tools that are able to reveal important aspects of the life of the patient that cannot be measured by a laboratory exam and/or a radiological procedure. The QoL is measured through multidimensional questionnaires on, at the very least, the domains of physical, psychological and social health. The improvement of the health care standards and the technological progress in medical matters have brought about an increase in the average age of the population, and as a consequence, an increase of the chronic and degenerative disease, which can negatively influence the patient’s quality of life. Amongst these pathologies, heart failure (HF) has a high prevalence in patients who are at least 70 years old, and it’s the cause of frequent and repeated hospitalizations. The estimate of the QoL becomes then a very important piece of the puzzle to figure out, as important as the clinical parameters, to allow the patient to become an integral part of the physician’s decisions and to reach more quickly and with better results the therapeutic objectives
A Social IoT-based platform for the deployment of a smart parking solution
Full text linkIn this paper, we propose a novel IoT-based smart parking (SP) solution which has been designed to provide information on the status of parking spots offered in on-street parking areas. We mostly focused on the following issues of the state of the art solutions: scalability, interoperability to address the heterogeneity of IoT devices, low energy consumption, and timely prediction of the availability of the parking spots. To this we leverage the Social IoT (SIoT) Lysis environment to create virtual entities of the real world objects involved in the SP system for on-street parking areas. The usage of the social virtual entities allows for addressing the interoperability issues among different types of IoT devices used by separate solutions deployed in adjacent areas. Magnetometer sensors are used to automatically detect the presence of a vehicle in each parking spot and the sensors data are collected through concentrators that cover the whole parking areas through low-energy Wi-Fi. Additionally, a control dashboard has been designed and developed to manage the monitored parking areas and provide responsive data analytics regarding the occupancy of parking areas in the city, which can be accessed through an Android App. Finally, a smart payment service allows the users to automatically pay for the used services making use of Bluetooth beacons. Experiments have been performed with the developed test-bed to show the performance of the system to timely detect the presence of a vehicle and identify the owner ID to trigger the payment procedure
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