Loading...
50 results
Search Results
Now showing 1 - 10 of 50
- Spy Walker: A Convenient Way to Assess Gait in Walker Assistive DevicesPublication . Viegas, Vítor; Pereira, José Miguel Costa Dias; Postolache, Octavian; Girão, Pedro SilvaThis paper presents the Spy Walker, a measurement system intended to characterize gait in walker assistive devices. The proposed system can be easily integrated into any commercial walker without any loss of native functionality. The system makes use of e-textile electrodes to sense the heart rate of the user, load cells to measure the force applied on the walker legs, and an inertial measurement unit to sense motion and orientation. These signals are sampled locally and then 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 steps. A rich set of parameters is presented for each step, including estimates of unbalance and motor incoordination, travelled distance and azimuth, and lift of the walker frame. This information can be used by a physiotherapist to assess objectively the physical condition of the user, and tune the rehabilitation therapy if needed.
- Sensor Communication Interfaces and StandardsPublication . Viegas, Vítor; Pereira, José Miguel Costa DiasThe chapter talks about the interfaces used to communicate with sensors and the standards available to channel data to higher logical levels. These communication interfaces and standards aim at abstracting the sensor layer in order to achieve interoperability at the layers above. Two standards are covered in detail: the IEEE 1451 standard that defines a smart transducer interface for sensors and actuators, and the Open Process Control (OPC) platform. The first one is an ongoing work with academic roots, while the second one is an industry-born platform. Both solutions are described in terms of architecture and internal structure, and are criticized in terms of pros and cons.
- 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.
- WSN Gait Monitoring for Objective Evaluation of Rehabilitation ProcessPublication . Postolache, Octavian; Pereira, José Miguel Costa Dias; Girão, Pedro Silva; Viegas, Vítor; Postolache, GabrielaA survey of wireless sensor network solutions for gait assessment is presented including own developed solution gait assessment based on smart insoles nodes ZigBee compatible characterized by multichannel force measurement and MEMS inertial measurement IMU. The system was developed to measure ground reaction force, acceleration and direction of feet in order to provide information to physiotherapists for an objective evaluation of rehabilitation effectiveness. Based on acquired data from the sensing channels a set of gait feature extraction such as walking speed stride length, swing time are calculated as part of gait analysis. Software for WSN node control, gait feature calculation and primary analysis of rehabilitation effectiveness developed for the physiotherapist was designed and implemented and preliminary tests were carried out for normal and simulated anomalous gait.
- Industrial Internet of the ThingsPublication . Viegas, Vítor; Pereira, José Miguel Costa Dias
- Wireless sensor network-based solution for environmental monitoring: water quality assessment case studyPublication . Postolache, Octavian; Pereira, José Miguel Costa Dias; Girão, Pedro SilvaThe challenges of climate change, population growth, demographic change, urbanization and resource depletion mean that the world’s great cities need to adapt to survive and thrive over the coming decades. Slashing greenhouse gas emissions to prevent catastrophic climate change, while maintaining or increasing quality of life, can be a costly and dif cult process. Two factors that directly affect the life quality in the XXI century cities are the water and air quality that can be monitored using the combination of low cost sensing modules, machine to machine (M2M) and internet of things (IoT) technologies. In this context, this study presents a wireless sensor network architecture that combines low cost sensing nodes and a low cost multi- parameters sensing probe for reliable monitoring of water quality parameters of surface waters (lakes, estuaries and rivers) in urban areas. A particular attention is dedicated to the design of the conductivity, temperature and turbidity signal conditioning circuits, highlighting important issues related to linearisation, measuring dynamic range and low-cost implementation by using commercial off-the-shelf components and devices. Several issues related to the wireless sensor network implementation are included in this study, as well as several simulation and experimental results.
- Monitoring Walker Assistive Devices: A Novel Approach Based on Load Cells and Optical Distance MeasurementsPublication . Viegas, Vítor; Pereira, José Miguel Costa Dias; Postolache, Octavian; Girão, Pedro SilvaThis paper presents a measurement system intended to monitor the usage of walker assistive devices. The goal is to guide the user in the correct use of the device in order to prevent risky situations and maximize comfort. Two risk indicators are defined: one related to force unbalance and the other related to motor incoordination. Force unbalance is measured by load cells attached to the walker legs, while motor incoordination is estimated by synchronizing force measurements with distance data provided by an optical sensor. The measurement system is equipped with a Bluetooth link that enables local supervision on a computer or tablet. Calibration and experimental results are included in the paper.
- Improved PWM A/D conversion technique: working principle and model validationPublication . Pereira, José Miguel Costa DiasAnalog-to-digital conversion plays a central role in any application of digital sensors and sensor systems that require an interface between analog devices, namely analog sensors, and digital devices, namely, microprocessors, digital signal processors or microcontrollers. With the advent of smart sensing, the integration of signal conditioning, analog-to-digital and digital data processing in single hardware devices became a reality. Moreover, the usage of low-cost discrete A/D conversion techniques for applications that are not critic in terms of accuracy, resolution or conversion rate, are considering increasingly mixed hardware and software A/D solutions tailored for specific application demands. In this context, this chapter presents a discrete low-cost A/D conversion solution based on pulse width modulation particularly suited for microcontrollers' integration with smart sensing devices.
- Gait Rehabilitation MonitorPublication . Leite, Paulo; Postolache, Octavian; Pereira, José Miguel Costa Dias; Postolache, GabrielaThis paper presents a simple wearable, non-intrusive affordable mobile framework that allows remote patient monitoring during gait rehabilitation by doctors and physiotherapists. The system includes a set of 2 Shimmer3 9DoF Inertial Measurement Units (IMUs), an Android smartphone and a developed app for collecting, primary processing of data and for persistence of data in a remote PostgreSQL database, which is available in a remote server and where further data processing is performed. This framework provides gait features classifier by invoking an implemented REST API available in the remote server. Low computational load algorithms based on Euler angles and filtered signals were developed and used for the classification and identification of several gait disturbances. These algorithms include the alignment of IMUs sensors data by means of a common temporal reference as well as heel strike and stride detection algorithms. After segmentation of the remotely collected signals for gait strides identification relevant features were extracted to feed, train and test a classifier for prediction of gait abnormalities using supervised machine learning type and Extremely Randomized Trees method.
- Moderation and moderated mediation in the analysis of non-nutritive sucking pattern of preterm newbornsPublication . Cunha, Manuel; Barreiros, João; Diniz, Ana; Pereira, José Miguel Costa Dias