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- Integrated e-Healthcare System for Elderly SupportPublication . Pires, Pedro; Moreira Mendes, Luís Miguel; Mendes, Jorge; Rodrigues, Rúben; Pereira, AntónioThe fast rise of the population aging verified in the last decades brings new challenges to the modern societies. Most elderly persons have the usual problems related to the old age, like health chronic problems and sensory and cognitive impairments. Therefore, it becomes essential to ensure the quality of life, safety and well-being to all elderly persons. The evolution of the sensors technology, low-power microelectronics and wireless communication standards allows that the gerontechnology be increasingly available and present in our society. This paper presents an integrated e-healthcare system for elderly support, which allows monitoring the biomedical parameters of a person in real time, anywhere and in any situation without interfering with its daily routines. The developed system comprises a personal biomedical data acquisition subsystem and an information storage center. The developed sensorial devices are responsible for acquiring and transmit wirelessly the biomedical signals to a smartphone or tablet. The collected information can also be saved in a storage center, where it can be managed and maintained. The medical data are accessible to the responsible entities for creating the medical history of the elderly persons to ensure a well-founded diagnosis. The high processing capacity of the developed electronic system enables the implementation of advanced algorithms for detection of health problems in order to ensure the safety and wellbeing of the elderly throughout the day. The medical assistance platform also provides to the elderlies telemedicine consultations in the comfort of their home if the videoconferencing service of the platform is used.
- Design Optimization of Radio Frequency Discrete Tuning VaractorsPublication . Moreira Mendes, Luís Miguel; Pires, Eduardo J. Solteiro; Oliveira, Paulo B. de Moura; Machado, José A. Tenreiro; Ferreira, Nuno M. Fonseca; Vaz, João Caldinhas; Rosário, Maria J.This work presents a procedure to automate the design of Si-integrated radio frequency (RF) discrete tuning varactors (RFDTVs). The synthesis method, which is based on evolutionary algorithms, searches for optimum performance RF switched capacitor array circuits that fulfill the design restrictions. The design algorithm uses the ε-dominance concept and the maximin sorting scheme to provide a set of different solutions (circuits) well distributed along an optimal front in the parameter space (circuit size and component values). Since all the solutions present the same performance, the designer can select the circuit that is best suited to be implemented in a particular integration technology. To assess the performance of the synthesis procedure, several RFDTV circuits, provided by the algorithm, were designed and simulated using a 0.18μm CMOS technology and the Cadence Virtuoso Design Platform. The comparisons between the algorithm and circuit simulation results show that they are very close,poi ting out that the proposed design procedure is a powerful design tool.
- Substrate noise isolation improvement in a single-well standard CMOS processPublication . Santos, P. Mendonça dos; Moreira Mendes, Luís Miguel; João Caldinhas VazThis work describes a fully CMOS compatible methodology, which makes available a pseudo deep n-well in single-well standard CMOS process. The proposed method is based on mask manipulation to accommodate the field implant p-type region into the n-well, and does not require any additional masks or modification in the CMOS process flow. According to the experimental results, the floating NMOS made available by the methodology shows a reduction in the threshold voltage, which implies a slight improvement in its performance, when compared with its standard NMOS counterpart. It was also experimentally demonstrated up to 3 GHz, that the guard-ring field implant/pseudo deep n-well proposed structure improves substrate noise isolation when compared to the classical p+ guard-ring, with a maximum improvement above 20 dB for low frequencies and a minimum of 4 dB at 3 GHz.
- Particle swarm optimization with fractional-order velocityPublication . Pires, E. J. Solteiro; Machado, J. A. Tenreiro; Oliveira, P. B. de Moura; Cunha, J. Boaventura; Mendes, LuísThis paper proposes a novel method for controlling the convergence rate of a particle swarm optimization algorithm using fractional calculus (FC) concepts. The optimization is tested for several wellknown functions and the relationship between the fractional order velocity and the convergence of the algorithm is observed. The FC demonstrates a potential for interpreting evolution of the algorithm and to control its convergence.
- Automated design of microwave discrete tuning differential capacitance circuits in Si‐integrated technologiesPublication . Mendes, Luís; Pires, E. J. Solteiro; Vaz, João C.; Rosário, Maria J.; Oliveira, P. B. de Moura; Machado, J. A. TenreiroA genetic algorithm used to design radio-frequency binary-weighted differential switched capacitor arrays (RFDSCAs) is presented in this article. The algorithm provides a set of circuits all having the same maximum performance. This article also describes the design, implementation, and measurements results of a 0.25 μm BiCMOS 3-bit RFDSCA. The experimental results show that the circuit presents the expected performance up to 40 GHz. The similarity between the evolutionary solutions, circuit simulations, and measured results indicates that the genetic synthesis method is a very useful tool for designing optimum performance RFDSCAs.
- A 130 nm CMOS LNA for 30 GHz applicationsPublication . Ribeiro, R.; Moreira Mendes, Luís Miguel; Vaz, J. C.; Rosario, M. J.; Freire, J. C.This paper presents the design of a 30 GHz low noise amplifier in a 130 nm CMOS technology. The amplifier is based on a cascode topology. The circuit uses autotransformers in the input and output matching networks. This design approach eliminates the necessity of the use of source degeneration and allows obtaining an ultra compact LNA. The amplifier presents a forward gain (S21) of 7.4 dB at 30 GHz with a bandwidth of 10 GHz, input and output VSWRs better than 1.22:1 and a noise figure of 3.7 dB. The LNA is unconditionally stable and consumes only 7 mW when supplied with 1.2 V. The amplifier fits an area of 0.08 mm2, which is one of the smallest areas reported.
- Maximin spreading algorithmPublication . Pires, E. J. Solteiro; Mendes, Luís; Lopes, António M.; Oliveira, P. B. de Moura; Machado, J. A. Tenreiro; Vaz, João; Rosário, Maria J.This paper presents a genetic algorithm to optimize uni-objective problems with an infinite number of optimal solutions. The algorithm uses the maximin concept and e-dominance to promote diversity over the admissible space. The proposed algorithm is tested with two well-known functions. The practical results of the algorithm are in good agreement with the optimal solutions of these functions. Moreover, the proposed optimization method is also applied in two practical real-world engineering optimization problems, namely, in radio frequency circuit design and in kinematic optimization of a parallel robot. In all the cases, the algorithm draws a set of optimal solutions. This means that each problem can be solved in several different ways, all with the same maximum performance.