Inbum Lee

Comparison of conductive fabric sensor and Ag-AgCl sensor under motion artifacts

A wearable electrocardiogram(ECG) device using conductive fabric sensor was compared with traditional Ag-AgCl electrode ECG device. The ECG signals were measured under existence of motion artifacts on variable running speed using treadmill to verify that wearable device can substitute traditional ECG device. A signal to noise ratio (SNR) and RR interval were compared between the two devices. The SNR of wearable device was similar or higher than that of clinical device and difference of RR interval was 2ms. The results show that the wearable ECG device using conductive fabric sensor can make similar performance with ECG device using Ag-AgCl electrode even under motion artifacts.

Performance Study of the Wearable One-Lead Wireless Electrocardiographic Monitoring System

This study attempts to compare and assess the performance of a wearable electrocardiogram (ECG) using a sensing fabric electrode and a Bluetooth network with a conventional ECG. A one-lead ECG examination was performed using Bioshirt and an iWorx 214 while walking or running at 3, 6, and 9 km per hour. A correlation coefficient of a heart rate variability (HRV) between these two devices was higher than 0.96 and power spectral density of HRV measured also showed an excellent agreement. Thus, both of these two ECG devices showed similar detection capability for R peaks. The measured values for wave duration and intervals of both devices concur with each other. The intensity of noise is controversial. The ECG device using a sensing fabric electrode and a wireless network showed an ECG signal detection and transmission capability similar to that of a conventional ECG device.

A basic study for patch type ambulatory 3-electrode ECG monitoring system for the analysis of acceleration signal and the limb leads and augmented unipolar limb leads signal

A compact and portable device was designed for preliminary study of patch type ambulatory 3-electrode ECG monitoring system for limb leads and augmented unipolar limb leads signal analysis. The developed system also can measure and send the acceleration signals wirelessly during daily life to analyze the users information. The 3-electrode system is feasible to provide the information of limb leads and augmented unipolar limb leads for further arrhythmia analysis and simultaneously shows lots of issues to be more broadly applicable and more powerful device.

A two-dimensional ultrasonic transducer having planar backing array electrodes

We have proposed the planar backing array electrodes implementation of a 2D ultrasonic transducer, which can minimize the complexity of backing electrodes interconnection with two dimensional transducer elements. The implementation consists of specially designed two layered planar top electrodes, instead of the complex circuit boards three-dimensionally interconnected with piezo-elements. Bias electrodes apply the voltage and control electrodes select the elements at which we want to apply the bias by shielding the field stretched on other elements. Potential distribution in a piezo-element was simulated to see the feasibility of the new concept using field shielding by two layered top electrodes array. The results indicate that the structural implementation of two layered electrode array is very important and specially designed two layered electrodes are enough to control the perfect ON/OFF state, showing that most of the voltage (>98%) applied across the sensor element can be shielded.