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- Transience analysis of bursty traffic with erbium doped fiber amplifiersPublication . Reis, Cláudia; Neto, Berta; Dionísio, Rogério Pais; Incerti, G.I.; Tosi-Beleffi, G.; Forin, D.; Teixeira, António; Rocha, A.M.; André, P.S.In this paper, we investigate experimentally the impact of optical amplifiers, namely Erbium Doped Fiber Amplifiers (EDFA) on Optical Burst Switching (OBS) networks, operating at 2.5 Gb/s (typical bit rate for current passive optical networks - PON). Bursts with 212 – 1 and 216 – 1 pseudo random binary sequence (PRBS) were studied, with different idle times. The use of traffic with variable idle time was assessed in order to evaluate the effect on the burst initial amplitude. We also analyzed the performance of the packet based system by measuring the Q factor at the receiver and concluded that the performance is not affected by the type of traffic (variable or fixed idle times).
- IoT system to monitor the well-being of senior citizens who self-isolate during the pandemicPublication . Gonçalves, Fábio; Jesus, Cassandra Sofia dos Santos; Fernandes, Francisco; Rosa, Rafaela; Dionísio, Rogério PaisThe COVID-19 pandemic and the need for selfisolation has decreased the frequency of visits to senior citizens by family members or caregivers. Because of this, many health concerns of the elderly remained unresolved. We created a IoT system, called Zelar@CB, that monitors the daily activities of isolated elderly people who do not have access to at-home care. The proposed project detects unusual activity by monitoring the person’s usage of electrical appliances to track if the user left the stove on or if there is a change in usage. It can also detect when the user falls, and sends an alert to family members or caregivers.
- Experimental study of a phase modulator using an active interferometric devicePublication . Dionísio, Rogério Pais; Reis, Cláudia; André, P.S.; Nogueira, Rogério; Teixeira, AntónioA novel architecture for an optical phase modulator is presented and experimentally demonstrated. This approach relies on a commercially available integrated Mach- Zehnder interferometer structure with Semiconductor Optical Amplifiers (MZI-SOA) and it is based in cross-phase modulation effect (XPM). The feasibility of the proposed optical phase modulator is experimentally investigated using different scenarios of input power and bit rates.
- Proceedings of the 5th International Conference on Production Economics and Project EvaluationPublication . Farinha, Luís; Araújo, Madalena; Rigueiro, Constança; Raposo, Daniel; Neves, João Vasco; Anjos, O.; Dionísio, Rogério PaisInternational Conference on Production Economics and Project Evaluation.
- Satellite IoT System Simulation with SEAMCAT: overview, modeling and analysisPublication . Dionísio, Rogério PaisSatellite IoT System Simulation with SEAMCAT: overview, modeling and analysis.
- Nyon-data : a fall detection dataset from a hinged board apparatusPublication . Dionísio, Rogério Pais; Rosa, Ana Rafaela; Jesus, Cassandra Sofia dos SantosNyon-data : a fall detection dataset from a hinged board apparatus.
- Industrial IoT devices and cyber-physical production systems: review and use casePublication . Rubio, Eva Masero; Dionísio, Rogério Pais; Torres, PedroThe present paper describes the state of the art related to IIoT Devices and Cyber-Physical systems and presents a use case related to predictive maintenance. Industry 4.0 is the boost for smart manufacturing and demands flexibility and adaptability of all devices/machines in the shop floor. The machines must become smart and interact with other machines inside and outside the industries/factories. The predictive maintenance is a key topic in this industrial revolution. The reason is based on the idea that smart machines must be capable to automatically identify and predict possible faults and actuate before they occur. Vibrations can be problematic in electrical motors. For this reason, we address an experimental study associated with an automatic classification procedure, that runs in the smart devices to detect anomalies. The results corroborate the applicability and usefulness of this machine learning algorithm to predict vibration faults.
- Nyon-data, a fall detection dataset from a hinged board apparatusPublication . Dionísio, Rogério Pais; Rosa, Ana Rafaela; Jesus, Cassandra Sofia dos SantosFalls are one of the causes of severe hilliness among elders, and the COVID-19 pandemic increased the number of unattended cases because of the social distancing measures. This study aims to create a dataset that collects the data from a 3-axis acceleration sensor fixed on a hinged board apparatus that mimics a human fall event. The datalogging system uses off-the-shelf devices to measure, collect and store the data. The resulting dataset includes data from different angle positions and heights, corresponding to joints of the lower limbs of the human body (ankle, knee, and hip). We use the dataset with a threshold-based fall detection algorithm. The result from the Receiver Operating Characteristic curve shows a good behavior with a mean Area Under the Curve of 0.77 and allow to compute a best threshold value with False Positive Rate of 14.8% and True Positive rate of 89.1%. The optimal threshold value may vary depending on the specific population, activity patterns, and environmental conditions, which may require further customization and validation in real-world settings.
- The extended information systems success measurement model : e-learning perspectivePublication . Lolić, Teodora; Stefanovic, Darko; Lalic, Danijela Ciric; Dionísio, Rogério Pais; Oliveira, Ângela; Pržulj, ĐorđeThis study investigated the crucial factors for measuring the success of the information system used in the e-learning process, considering the transformations in the work environment. This study was motivated by the changes caused by COVID-19 witnessed after the shift to fully online learning environments supported by e-learning systems, i.e., learning emphasized with information systems. Empirical research was conducted on a sample comprising teaching staff from two European universities: the University of Novi Sad, Faculty of Technical Sciences in Serbia and the Polytechnic Institute of Castelo Branco in Portugal. By synthesizing knowledge from review of the prior literature, supported by the findings of this study, the authors propose an Extended Information System Success Measurement Model—EISSMM. EISSMM underlines the importance of workforce agility, which includes the factors of proactivity, adaptability, and resistance to change, in the information system performance measurement model. The results of our research provide more extensive evidence and findings for scholars and practitioners that could support measuring information system success primarily in e-learning and other various contextual settings, highlighting the importance of people’s responses to work environment changes.
- PoPu-Data: a multilayered, simultaneously collected lying position datasetPublication . Fonseca, Luís Filipe Rodrigues; Ribeiro, Fernando Reinaldo; Metrôlho, J.C.M.M.; Santos, Adriana; Dionísio, Rogério Pais; Amini, Mohammad; Silva, Arlindo F.; Heravi, Ahmad Reza; Sheikholeslami, Davood Fanaei; Fidalgo, Filipe; Rodrigues, Francisco; Santos, Osvaldo; Coelho, Patrícia; Aemmi, Seyyed SajjadThis study presents a dataset containing three layers of data that are useful for body position classification and all uses related to it. The PoPu dataset contains simultaneously collected data from two different sensor sheets—one placed over and one placed under a mattress; furthermore, a segmentation data layer was added where different body parts are identified using the pressure data from the sensors over the mattress. The data included were gathered from 60 healthy volunteers distributed among the different gathered characteristics: namely sex, weight, and height. This dataset can be used for position classification, assessing the viability of sensors placed under a mattress, and in applications regarding bedded or lying people or sleep related disorders.