2019
Authors
Lopes, EM; Sevilla, A; Vilas Boas, MD; Choupina, HMP; Nunes, DP; Rosas, MJ; Oliveira, A; Massano, J; Vaz, R; Cunha, JPS;
Publication
2019 9TH INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING (NER)
Abstract
DBS surgery is considered for Parkinson's Disease patients when motor complications and consequent quality of life is no longer acceptable on optimal medical therapy prescribed by neurologists. Within the operating room, the electrode placement with the best clinical outcome for the patient is quantitatively assessed via the wrist rigidity assessment. A subjective scale is used, influenced by the neurologists' perception and experience. Our research group has previously designed a novel, comfortable and wireless system aiming to tackle this subjectivity. This system comprised a gyroscope sensor in a textile band, placed in the patients' hand, which communicated its measurement to a Smartphone via Bluetooth. During the wrist rigidity evaluation exam, a signal descriptor was computed from angular velocity (omega) and a polynomial mathematical model was used to classify the signals using a quantitative scale of rigidity improvement. In this present work, we aim to develop models that consider the 3-gyroscope-axes to acquire the omega and the cogwheel rigidity. Our results showed that y-gyroscope-axis remains the best way to classify the rigidity reduction, showing an accuracy of 78% and a mean error of 3.5%. According to previous results, the performance was similar and the decrease of samples to extract the omega features did not compromise system performance. The cogwheel rigidity did not improve the previous model and other gyroscope-axis beyond the y-axis decreased system performance.
2019
Authors
Mehrasa, M; Pouresmaeil, E; Soltani, H; Blaabjerg, F; Calado, MRA; Catalao, JPS;
Publication
APPLIED SCIENCES-BASEL
Abstract
This paper provides virtual inertia and mechanical power-based double synchronous controller (DSC) for power converters based on the d- and q-components of the converter current to assure the stable operation of the grid with the penetration of large-scale renewable energy resources (RERs). The DSC is projected based on emulating both the inertia and mechanical power variables of the synchronous generators (SGs), and its performance is compared with a non-synchronous controller (NSC) that is without these emulations. The main contributions of the DSC are providing a large margin of stability for the power grid with a wide area of low and high values of virtual inertia, also improving significantly power grid stability (PGS) with changing properly the embedded virtual variables of inertia, mechanical power, and also mechanical power error. Also, decoupling features of the proposed DSC in which both d and q components are completely involved with the characteristics of SGs as well as the relationship between the interfaced converter and dynamic models of SGs are other important contributions of the DSC over the existing control methods. Embedding some coefficients for the proposed DSC to show its robustness against the unknown intrinsic property of parameters is another contribution in this paper. Moreover, several transfer functions are achieved and analyzed that confirm a more stable performance of the emulated controller in comparison with the NSC for power-sharing characteristics. Simulation results confirm the superiority of the proposed DSC in comparison with other existing control techniques, e.g., the NSC techniques.
2019
Authors
Rocha, T; Nunes, RR; Barroso, J; Martins, P;
Publication
ACM International Conference Proceeding Series
Abstract
In this paper, it is described a multimedia interactive technology to enhance learning for children with learning disabilities. Developed with a user-centered design philosophy, it aims to present an easy user interaction environment to focus students on learning of reading and/or writing activities. With this purpose, it is described the solution developed and the usability assessment, through heuristics and user tests. The heuristics results revealed some minor problems in the design contents (that will be treated in a second version). However, the user tests showed children performed all tasks with success, not only in the offered time but also with no difficulty. Furthermore, they seemed satisfied and motivated to continue the interaction autonomously. © 2019 Association for Computing Machinery.
2019
Authors
Goncalves, TIG; Sousa, PSA; Moreira, MRA;
Publication
MANAGEMENT AND PRODUCTION ENGINEERING REVIEW
Abstract
Studies linking the use of lean practices to company performance have been increasing as markets are becoming more competitive and companies are eager for reducing waste and therefore implementing the Lean Management (LM) philosophy to improve performance. However, results from these studies have found various and different impacts and some light is needed. Extant literature was reviewed and, to achieve the research objective, a meta-analysis of correlations was carried out. The obtained results suggest a positive relationship between some lean practices and performance measures. Furthermore, the presence of moderators influencing the relationship between lean practices and performance outcomes is highlighted in our results. To our best knowledge, this is the first research that proposes a comparison of results from primary studies on Lean implementation, by analysing the linear relationship between lean practices and enterprise performance. It fills this gap and therefore represents an important contribution.
2019
Authors
Sarmento, RP; Lemos, L; Cordeiro, M; Rossetti, G; Cardoso, D;
Publication
CoRR
Abstract
2019
Authors
Frazao, I; Abreu, PH; Cruz, T; Araújo, H; Simoes, P;
Publication
CRITICAL INFORMATION INFRASTRUCTURES SECURITY (CRITIS 2018)
Abstract
Denial of Service attacks, which have become commonplace on the Information and Communications Technologies domain, constitute a class of threats whose main objective is to degrade or disable a service or functionality on a target. The increasing reliance of Cyber-Physical Systems upon these technologies, together with their progressive interconnection with other infrastructure and/or organizational domains, has contributed to increase their exposure to these attacks, with potentially catastrophic consequences. Despite the potential impact of such attacks, the lack of generality regarding the related works in the attack prevention and detection fields has prevented its application in real-world scenarios. This paper aims at reducing that effect by analyzing the behavior of classification algorithms with different dataset characteristics. © 2019, Springer Nature Switzerland AG.
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