Percorrer por autor "Postolache, Octavian"
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- Application of force and inertial sensors to monitor gait on legacy walkersPublication . Viegas, Vitor; Pereira, José Miguel Costa Dias; Postolache, Octavian; Girão, Pedro SilvaWalker assistive devices play an important role in extending the autonomy of elderly people and in recovering the mobility of people affected by locomotion disabilities. The next generation of walkers are hoped to include embedded sensors and data processing capabilities that will allow for the extraction of objective metrics (about gait and body posture) to assist the work of physiotherapists and to enable the self-control nature of walker usage. The paper presents the Andante, our latest proposal of a smart walker intended to monitor and analyze gait in real time. The system makes use of e-textile electrodes to sense the heart rate of the user, load cells to measure the forces applied on the walker legs, and an inertial measurement unit to sense motion and orientation. These signals are sampled locally and transferred over a Bluetooth link to a remote host, where they are processed in real time. Data processing includes the detection, classification, and characterization of the steps. A rich set of parameters is presented for each step, including estimates of balance and motor coordination, step length and azimuth, and lift of the walker frame. This information can be used by physiotherapist to objectively assess the physical condition of the user and tune rehabilitation therapy if needed. The proposed solution can be easily integrated into any commercial walker without any loss of functionality.
- Assistive Smart Sensing Devices for Gait Rehabilitation MonitoringPublication . Postolache, Octavian; Pereira, José Miguel Costa Dias; Ribeiro, M.; Girão, Pedro Silva
- Combining Distance and Force Measurements to Monitor the Usage of Walker Assistive DevicesPublication . Pereira, José Miguel Costa Dias; Viegas, Vítor; Postolache, Octavian; Girão, Pedro SilvaThis paper presents a measurement system that can be used to monitor the usage of walker assistive devices. The forces applied on the legs of the walker device are measured using low cost force sensing resistors and a light detection and ranging device is used to evaluate several gait kinematic parameters, such as, walking speed and walking stride length. To evaluate the right usage of the walker device two walker indexes, one related with the applied forces and the other related with walker gait phases, are introduced. The measurement system includes wireless communication capabilities that enable a local and remote supervision of the measuring data.
- Combining distance and force measurements to monitor the usage of walker assistive devicesPublication . Pereira, José Miguel Costa Dias; Viegas, Vítor; Postolache, Octavian; Girão, Pedro SilvaThis paper presents a measurement system that can be used to monitor the usage of walker assistive devices. The forces applied on the legs of the walker device are measured using low cost force sensing resistors and a light detection and ranging device is used to evaluate several gait kinematic parameters, such as, walking speed and walking stride length. To evaluate the right usage of the walker device two walker indexes, one related with the applied forces and the other related with walker gait phases, are introduced. The measurement system includes wireless communication capabilities that enable a local and remote supervision of the measuring data.
- A Dual Measurement and Stimulating System to Monitor and Promote NNSPublication . Pereira, José Miguel Costa Dias; Viegas, Vítor; Postolache, Octavian; Girão, P. S.The present paper presents a dual system that can be used to measure and to generate non-nutritive sucking (NNS) signals. The NNS measurement is based on a pressure sensor that is pneumatically connected to a silicone pacifier. By its turn, the NNS stimulator is based on a miniature pump and a miniature electro-valve that are operated by opposite phased signals to produce the pulsed pressure signal that is pneumatically applied to the silicone pacifier. The paper highlights some specific issues related with the calibration of the pneumatic signal measuring chain. Processing and wireless transmission capabilities are provided by a low-cost solution based on a microcontroller. Calibration and experimental results are also included in the paper.
- A dual-proposal device for condition-based maintenance and energy harvesting in the context of IIoT applicationsPublication . Pereira, José Dias; Viegas, Vitor; Postolache, Octavian; Girão, Pedro SilvaThis paper presents a dual-purpose device for condition-based maintenance (CBM) and for energy harvesting (EH) in IIoT applications. Vibration monitoring in industrial environments is a key indicator for predictive maintenance purposes and for energy harvesting. The paper includes the description of the hardware and software of a flexible platform that permits vibration measurements, vibration sensor calibration and energy harvesting testing. The vibration exciter included in the platform can be controlled by the output signal of a common signal generator. The platform also includes a differential temperature sensor that can gather additional data for CBM purposes. The final part of the paper includes experimental results of a vibration sensor under characterization and of the performance evaluation of a commercial EH module.
- Emotions Assessment on Simulated FlightsPublication . Roza, V. C.; Postolache, Octavian; Groza, V.; Pereira, José Miguel Costa Dias
- Fieldbus: Developing a Laboratory Prototype for Leaning PurposesPublication . Pereira, José Miguel Costa Dias; Viegas, Vítor; Postolache, Octavian; Girão, Pedro SilvaThis paper presents a distributed control and measurement system based on the Foundation Field Bus protocol. A system’s prototype is described together with some implementation details and experimental results. The system also includes interfaces for conventional measurement and control devices that are connected through 4-20 mA current loops. The proposed prototype seems to be a very suitable solution for teaching purposes since it is an open solution that can be used to integrate devices from different manufacturers, as long as the prototype is provided with the appropriate interface.
- A flexible, low-cost and algorithm-independent calibrator for automated blood pressure measuring devicesPublication . Dias Pereira, José Miguel Costa; Ribeiro, Gonçalo; Postolache, OctavianArterial hypertension is one of the most important public health problems, especially in developed countries. The quality and calibration of blood pressure (BP) equipment used for non-invasive blood pressure (NIBP) measurement are essential to obtain accurate data that support correct medical diagnostics. This paper includes the hardware and software description of a flexible, low-cost and algorithm-independent calibrator prototype that can be used for the static and dynamic calibration of automated blood pressure measuring devices (ABPMDs). In the context of this paper, the meaning of calibrator flexibility is mainly related to its ability to adapt or change easily in response to different situations in terms of the calibration of ABPMDs that can use a variety of calibration settings without the need to use specific oscillometric curves from different ABPMD manufacturers. The hardware part of the calibrator includes mainly an electro-pneumatic regulator, used to generate dynamic pressure signals with arbitrary waveforms, amplitudes and frequencies, a pressure sensor, remotely connected through a pneumatic tube to the blood pressure (BP) cuff, a blood pressure release valve and analog conditioning circuits, plus the A/D converter. The software part of the calibrator, mainly developed in LabVIEW 20, enables the simulation of oscillometric pressure pulses with different envelope profiles and the implementation of the main algorithms that are typically used to evaluate systolic, diastolic and mean arterial pressure values. Simulation and experimental results that were obtained validate the theoretical expectations and show a very acceptable level of accuracy and performance of the presented NIBP calibrator prototype. The prototype calibration results were also validated using a certified NIBP calibrator that is frequently used in clinical environments.
- Gait assessment using microwave radars mounted on standard walkerPublication . Postolache, Octavian; Pereira, José Dias; Viegas, Vítor—Gait rehabilitation is a complex process considering the complexity of movement that involves different parts of the human body. To assure the safety of the rehabilitation process walking aids are a common indication in clinics, the standard walker being one of the most prescribed taking into account its stability. Embedding sensors on the level of the walker can provide additional capabilities associated with gait monitoring that may be used to evaluate the user gait ehabilitation outcome. Sensing user motion during walker usage can be also used to avoid wrong usage that can conduct to falls. In the current study a standard walker with two Microwave Doppler radars was implemented to extract information on user gait during the rehabilitation process as well as information about the sequence of the standard walker usage. The signals acquired from the measurement channels were considered for time-frequency analysis, including features extraction such as mean instantaneous frequency (MIF) and mean instantaneous bandwidth (MIB) to characterize normal and abnormal gait. The capabilities of time-frequency analysis methods as the starting point on gait classification is also considered.