Anh Dinh

Implementation of a Physical Activity Monitoring System for the Elderly People with Built-in Vital Sign and Fall Detection

Physical activity monitoring of the elderly people provides valuable information for health aware services. This paper presents the implementation of a system to sense, send, display and store physiology activity. The system includes a wearable device to be worn by the individual to collect physical activity data, a wireless communication link between the patient and the monitoring network. A fall detection and heart beat measurement are also included to provide better monitoring. Testing results show the system function properly and provide accurate fall detection and data for monitoring purpose.

A Fall and Near-Fall Assessment and Evaluation System

The FANFARE (Falls And Near Falls Assessment Research and Evaluation) project has developed a system to fulfill the need for a wearable device to collect data for fall and near-falls analysis. The system consists of a computer and a wireless sensor network to measure, display, and store fall related parameters such as postural activities and heart rate variability. Ease of use and low power are considered in the design. The system was built and tested successfully. Different machine learning algorithms were applied to the stored data for fall and near-fall evaluation. Results indicate that the Naïve Bayes algorithm is the best choice, due to its fast model building and high accuracy in fall detection.

Implementation of a wearerable real-time system for physical activity recognition based on Naive Bayes classifier

In this paper, we implement a wearable real-time system on the Sun SPOT wireless sensors with Naive Bayes algorithm to recognize physical activity. Naive Bayes algorithm is demonstrated to work better than other algorithms both in accuracy performance and computational time in this particular application. 20Hz is selected as the sampling rate. In terms of sensor location, one sensor attached to the thigh with 87.55% overall accuracy provides the most useful information than the shank or the chest. If two sensors are available, the combination of attaching them to the left thigh and the right thigh respectively is demonstrated to be optimal solution for recognizing physical activity, with 90.52% overall accuracy.

A low latency architecture for computing multiplicative inverses and divisions in GF(2/sup m/)

A low latency architecture to compute the multiplicative inverse and division in a finite field GF (2/sup m/) is presented. Compared to other proposals with the same complexity, this circuit has lower latency and can be used in error-correction or cryptography to increase system throughput. This architecture takes advantage of the simplicity to computing powers (2/sup l/) of an element in the Galois Field. The inverse of an element is computed in two stages: power calculation and multiplication. A division can be performed using only one more multiplication in the inversion circuit.

Pulse transit time-based blood pressure estimation using hilbert-huang transform

The pulse transit time (PTT) based method has been suggested as a continuous, cuffless and non-invasive approach to estimate blood pressure. It is of paramount importance to accurately determine the pulse transit time from the measured electrocardiogram (ECG) and photoplethysmo-gram (PPG) signals. We apply the celebrated Hilbert-Huang Transform (HHT) to process both the ECG and PPG signals, and improve the accuracy of the PTT estimation. Further, the blood pressure variation is obtained by using a well-established formula reflecting the relationship between the blood pressure and the estimated PTT. Simulation results are provided to illustrate the effectiveness of the proposed method.

Data acquisition system using six degree-of-freedom inertia sensor and Zigbee wireless link for fall detection and prevention

Fall detection and prevention require logged physiological activity data of a patient for a long period of time. This work develops a data acquisition system to collect motion data from multiple patients and store in a data base. A wireless sensor network is built using high precision inertia sensors and low power Zigbee wireless transceivers. Testing results prove the system function properly. Researchers and physicians can now retrieve and analyze the accurate data of the patient movement with ease.

Bandage-size non-ECG heart rate monitor using ZigBee wireless link

Heart rate is an indication for the health of a human being. Traditionally, ECG signal is used to measure and monitor heart rate. This design uses a simple technique to pick up the sound of the heart beat and send the beat signal wirelessly to a computer. The system is a low-cost with a very small size, light weight and easy to use by the patient. A microphone is used to pick up the sound of the heart beat. The signal is processed, sampled and sent wirelessly using ZigBee protocol. Experimental results show the system functioning properly. Heart beat signals are sensed, sent, displayed, monitored, stored, reviewed, and analyzed with ease. Flexible PCB can be used to further reducing size and weight of the sensing unit.

Correlation between seismocardiogram and systolic blood pressure

Modern health care system requires certain critically ill patients to monitor their blood pressure continuously through non-invasive techniques. The pulse transit time (PTT) and other parameter such as RS2 have been used previously for continuous BP monitoring. In this study, a system is designed using trial axis accelerometer as a sensor to collect seismocardiogram (SCG) data. The SCG waveforms have been used to find a relationship between Systolic Blood Pressure (SBP) and different axis of Seismocardiogram on 10 subjects aged 24+ years. The results reflect that the SBP is correlated with the starting point of the SCG wave in the x-axis to the mid-point of the z-axis. Their mean correlation and equations have been found which can state the systolic blood pressure of the subjects. The relative errors between the calculated SBP and the SBP measured from clinical equipment are up to 123 mmHg in normal range and 456 mmHg in high range. In summary, SCG can be used to determine the SBP as it has a moderate correlation.

A RHBD LC-Tank Oscillator Design Tolerant to Single-Event Transients

A single-event transients (SETs) tolerant LC-tank oscillator was designed, simulated, and fabricated using CMOS 90 nm technology. The simulation and experimental results indicate that the bias current of the oscillator greatly affects the SET-tolerance of an LC-tank oscillator. Adding a decoupling resistor to the bias circuit is an effective way to mitigate the effect of SETs to the oscillator. Laser testing and simulation results show significant reduction in the SET-induced amplitude and phase shifts of the VCO output.

A Novelistic Fractal Antenna for Ultra Wideband (UWB) Applications

Fractal arrays are used to increase the bandwidth of the antenna and to reduce grating lobes. The frequency range from 3.1 to 10.6GHz is specially allocated for the UWB applications. In this paper, a novel antenna based on fractal concepts for ultra wideband (UWB) applications is analyzed, designed, fabricated and tested. Further the antenna is analyzed using the emerging fractal concepts and transmission line method (TLM). The proposed antenna has a good gain bandwidth with broadside radiation pattern. This design is suitable for 3D IC inter-chip and intra-chip communication, and medical imaging applications. This is called Levys antenna.