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Publications

2020

Closed Against Open Innovation: A Comparison Between Apple and Xiaomi

Authors
Lajoso, J; Sousa, A; Albuquerque, J; Mineiro, R; Au Yong Oliveira, M;

Publication
Advances in Intelligent Systems and Computing

Abstract
One of the biggest, most competitive and quicker shifting markets is the smartphone industry. Evaluating significant opportunities and being sustainable in the market is entirely up to a firm’s innovation strategy. In this article, we perform an in-depth analysis by available means to study trends and tendencies relative to Apple and Xiaomi, two completely different companies with completely different approaches. We tested the clients’ needs and perceptions, in an attempt to see if they are part of the enterprises’ strategy (in a survey, with 193 responses). Indeed, customers are interested in powerful cameras, good storage capacity and a good duration of the battery of their smartphones. The market is evaluated above 1.5 billion units sold per year and demonstrates high demand for every new model to be different, more powerful, more capable of fulfilling our lifestyle. Apple uses an incremental innovation sales strategy, based on the billions of euros used in secret research and development. On the other hand, Xiaomi performs open innovation, taking customers’ needs and ideas to the world. What is the best approach? Will it be enough to stay on top? An analysis using Google Trends shows how Nokia has faded away over time, how Apple had a spike of interest concerning its latest iPhone 11 launch; while Xiaomi is ever more popular, especially in Portugal. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.

2020

Simulation of Abnormal Physiological Signals in a Phantom for Bioengineering Education

Authors
Vieira, H; Costa, N; Alves, J; Coelho, LP;

Publication
INTERNATIONAL JOURNAL OF ONLINE AND BIOMEDICAL ENGINEERING

Abstract
In clinical practice and in particular in the diagnostic process, the assessment of cardiac and respiratory functions is supported by electrocardiogram and auscultation. These exams are non-invasive, quick and inexpensive to perform and easy to interpret. For these reasons, this type of assessment is a constant in the daily life of a clinician and the information obtained is central to the decision-making process. Therefore, it is essential that during their training, students of health-related subjects acquire skills in the acquisition and evaluation of the referred physiological signals. Simulation, considering the technological possibilities of today, is an excellent preparation tool since it exposes trainees to near real contexts but without the associated risks. Hence, the simulation of physiological signals plays an important role in the education of healthcare professionals, bioengineering professionals and also in the development and calibration of medical devices. This paper describes a project to develop synchronized electrocardiogram (ECG), phonocardiogram (PCG) and breathing sounds simulators that aims to improve an existing phantom simulator. The developed system allows, in an integrated way, to generate normal and pathological signals, being contemplated several distinct pathologies. For engineering education, it is also possible to simulate the introduction of signal disturbances or hardware malfunctions.

2020

System Identification of <i>Just Walk</i>: Using Matchable-Observable Linear Parametrizations

Authors
dos Santos, PL; Freigoun, MT; Martín, CA; Rivera, DE; Hekler, EB; Romano, RA; Perdicoulis, TPA;

Publication
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY

Abstract
System identification approaches have been used to design an experiment, generate data, and estimate dynamical system models for Just Walk, a behavioral intervention intended to increase physical activity in sedentary adults. The estimated models serve a number of important purposes, such as understanding the factors that influence behavior and as the basis for using control systems as decision algorithms in optimized interventions. A class of identification algorithms known as matchable-observable linear identification has been reformulated and adapted to estimate linear time-invariant models from data obtained from this intervention. The experimental design, estimation algorithms, and validation procedures are described, with the best models estimated from data corresponding to an individual intervention participant. The results provide insights into the individual and the intervention, which can be used to improve the design of future studies.

2020

Optimal power management of dependent microgrid considering distribution market and unused power capacity

Authors
MansourLakouraj, M; Shahabi, M; Shafie khah, M; Ghoreishi, N; Catalao, JPS;

Publication
ENERGY

Abstract
This study presents an optimal power management for a microgrid (MG) in distribution market environment. The MG operator is able to have interactions with the distribution market operator (DMO) and adjacent MG (AMG) operator to supply its local loads. The DMO regulates the electricity market, and assigns the electricity price and power profile for the MG. The motivation behind the use of The DMO is that it works as an entity between MG and independent system operator (ISO) in order to guarantee a flexible operation by reducing power fluctuation and reduce the unintentional peak loads in low market price hours. The unused power capacity in AMG is used during the islanded hours through an additional interconnection point connected to the MG. Using this method reduces the need for installing new generation resources, which will be a practical and economical solution for MG developer. This MG which is able to provide power from distribution market and the AMG with two interconnection points is named dependent MG (DMG). A market-based stochastic model containing distribution market constraints and AC power flow formulations employs conditional value at risk (CVaR) methodology to capture the loads and wind uncertainties. The effectiveness of the presented model is evaluated on a 20 kV test system using different case studies. In this test system, the operator is the owner of all generation units. The numerical analysis explicate that presented model reduces the operation cost of DMG with the aim of responsive loads, unused power capacity, energy storage system (ESS) and power generation units. The market-based scheduling also provides operational flexibility for distribution system by adjusting flexibility limit of market constraints. It is also shown that changing risk preferences level changes the power generation pattern in ESS and causes a costly operation of resources in risk-averse strategy. The competence of this model is significant when the preventive maintenance (PM) program is carried out, and the DMG should rely on its flexible resources and AMG's available power capacity, which could reduce the load shedding.

2020

Empowering Users Through a Privacy Middleware Watchdog

Authors
Sousa, PR; Martins, R; Antunes, L;

Publication
TRUST, PRIVACY AND SECURITY IN DIGITAL BUSINESS, TRUSTBUS 2020

Abstract
The ever-increasing number of interconnected devices in smart environments, i.e., homes and cities, is bolstering the amount of data generated and exchanged. These devices can range from small embedded platforms, such as those included in home appliances, to critical operational systems, such as traffic lights. However, this increasing adoption is raising significant security and privacy concerns. Although some researchers have already solved some of these issues, data privacy still lacks a viable solution, especially when considering a flexible, decentralized approach to avoid a central overseer. One of the biggest challenges regarding privacy is the lack of transparency about how data flows are mediated and regulated as, often, these resources share data with external entities without the users' knowledge. We argue that a novel data-sharing control mechanism is required to properly control users' privacy and their respective Internet of Things (IoT) devices. This work focuses on a middleware layer solution for the IoT devices, which allows the control of the data generated by the device by its owner. The platform places the user as an active participant in the data market, behaving as its own data intermediary for potential consumers by monitoring, controlling, and negotiating the usage of their data.

2020

Evaluation of Combined Artificial Intelligence and Radiologist Assessment to Interpret Screening Mammograms

Authors
Schaffter, T; Buist, DSM; Lee, CI; Nikulin, Y; Ribli, D; Guan, Y; Lotter, W; Jie, Z; Du, H; Wang, S; Feng, J; Feng, M; Kim, HE; Albiol, F; Albiol, A; Morrell, S; Wojna, Z; Ahsen, ME; Asif, U; Jimeno Yepes, A; Yohanandan, S; Rabinovici Cohen, S; Yi, D; Hoff, B; Yu, T; Chaibub Neto, E; Rubin, DL; Lindholm, P; Margolies, LR; McBride, RB; Rothstein, JH; Sieh, W; Ben Ari, R; Harrer, S; Trister, A; Friend, S; Norman, T; Sahiner, B; Strand, F; Guinney, J; Stolovitzky, G; Mackey, L; Cahoon, J; Shen, L; Sohn, JH; Trivedi, H; Shen, Y; Buturovic, L; Pereira, JC; Cardoso, JS; Castro, E; Kalleberg, KT; Pelka, O; Nedjar, I; Geras, KJ; Nensa, F; Goan, E; Koitka, S; Caballero, L; Cox, DD; Krishnaswamy, P; Pandey, G; Friedrich, CM; Perrin, D; Fookes, C; Shi, B; Cardoso Negrie, G; Kawczynski, M; Cho, K; Khoo, CS; Lo, JY; Sorensen, AG; Jung, H;

Publication
JAMA NETWORK OPEN

Abstract
Importance Mammography screening currently relies on subjective human interpretation. Artificial intelligence (AI) advances could be used to increase mammography screening accuracy by reducing missed cancers and false positives. Objective To evaluate whether AI can overcome human mammography interpretation limitations with a rigorous, unbiased evaluation of machine learning algorithms. Design, Setting, and Participants In this diagnostic accuracy study conducted between September 2016 and November 2017, an international, crowdsourced challenge was hosted to foster AI algorithm development focused on interpreting screening mammography. More than 1100 participants comprising 126 teams from 44 countries participated. Analysis began November 18, 2016. Main Outcomes and Measurements Algorithms used images alone (challenge 1) or combined images, previous examinations (if available), and clinical and demographic risk factor data (challenge 2) and output a score that translated to cancer yes/no within 12 months. Algorithm accuracy for breast cancer detection was evaluated using area under the curve and algorithm specificity compared with radiologists' specificity with radiologists' sensitivity set at 85.9% (United States) and 83.9% (Sweden). An ensemble method aggregating top-performing AI algorithms and radiologists' recall assessment was developed and evaluated. Results Overall, 144 & x202f;231 screening mammograms from 85 & x202f;580 US women (952 cancer positive <= 12 months from screening) were used for algorithm training and validation. A second independent validation cohort included 166 & x202f;578 examinations from 68 & x202f;008 Swedish women (780 cancer positive). The top-performing algorithm achieved an area under the curve of 0.858 (United States) and 0.903 (Sweden) and 66.2% (United States) and 81.2% (Sweden) specificity at the radiologists' sensitivity, lower than community-practice radiologists' specificity of 90.5% (United States) and 98.5% (Sweden). Combining top-performing algorithms and US radiologist assessments resulted in a higher area under the curve of 0.942 and achieved a significantly improved specificity (92.0%) at the same sensitivity. Conclusions and Relevance While no single AI algorithm outperformed radiologists, an ensemble of AI algorithms combined with radiologist assessment in a single-reader screening environment improved overall accuracy. This study underscores the potential of using machine learning methods for enhancing mammography screening interpretation. Question How do deep learning algorithms perform compared with radiologists in screening mammography interpretation? Findings In this diagnostic accuracy study using 144 & x202f;231 screening mammograms from 85 & x202f;580 women from the United States and 166 & x202f;578 screening mammograms from 68 & x202f;008 women from Sweden, no single artificial intelligence algorithm outperformed US community radiologist benchmarks; including clinical data and prior mammograms did not improve artificial intelligence performance. However, combining best-performing artificial intelligence algorithms with single-radiologist assessment demonstrated increased specificity. Meaning Integrating artificial intelligence to mammography interpretation in single-radiologist settings could yield significant performance improvements, with the potential to reduce health care system expenditures and address resource scarcity experienced in population-based screening programs. This diagnostic accuracy study evaluates whether artificial intelligence can overcome human mammography interpretation limits with a rigorous, unbiased evaluation of machine learning algorithms.

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