Vega Pradana Rachim

Pohang University of Science and Technology | POSTECH · Department of Creative IT Engineering

We propose a multimodal biosensor for use in continuous blood pressure (BP) monitoring system. Our proposed novel configuration measures photo-plethysmography (PPG) and impedance plethysmography (IPG) signals simultaneously from the subject wrist. The proposed biosensor system enables a fully non-intrusive system that is cuff-less, also utilize a s...

One of the best ways to obtain health information is from an electrocardiogram (ECG). Through an ECG, characteristics such as patients' heartbeats, heart conditions, and heart disease can be analyzed. Unfortunately, most available healthcare devices do not provide clinical data such as information regarding patients' heart activities. Many research...

Diabetes is a worldwide-serious problem that can only be delayed or prevented by a regular monitoring of blood glucose (BG) concentration level. Continuous monitoring systems allow subjects to prepare the diabetes management strategy and prevent the long-term complications diseases. Until now, most studies utilize various biofluids such as sweat, t...

Sleep apnea is often diagnosed using an overnight sleep test called a polysomnography (PSG). Unfortunately, though it is the gold standard of sleep disorder diagnosis, a PSG is time consuming, inconvenient, and expensive. Many researchers have tried to ameliorate this problem by developing other reliable methods, such as using electrocardiography (...

Recent advances in scalable fabrication methods based on printing technologies have improved the yield and lowered the cost of manufacturing epidermal sensors. However, modern technologies still require expensive multi‐bio‐ink raw materials. A laser‐centric fabrication method that realizes a cost‐effective, scalable, and streamlined fabrication pro...

Thin-film microfabrication-based bio-integrated sensors are widely used for a broad range of applications that require continuous measurements of biophysical and biochemical signals from the human body. Typically, they are fabricated using standard photolithography and etching techniques. This traditional method is capable of producing a precise, t...

The state-of-the-art systems for blood pressure (BP) monitoring often use cuffed-based rigid sensory systems, bulky electronics, multiple measurement sites, and intermittent measurement. Here, we introduce a new type of epidermal electronics that were specifically designed for cuffless BP-monitoring system, named multiPANI. The proposed fully integ...

A flexible, patch-type strain sensor is described for continuous monitoring of pulse waves. The proposed sensor exploits the piezo-resistivity of the conductive polymer, polyaniline (PANI), to detect dynamic volume changes in blood vessels owing to pulse waves. The proposed PANI film was fabricated through electrodeposition, which is considered as...

Compressive Sensing (CS) is an emerging technique in Internet of Medical Things (IoMT) application especially for smart wearable devices to prolong the sensor lifetime, and enable a continuous healthcare monitoring system. This paper describes the performance of CS on our wrist-based cuff-less biosensor for estimating blood pressure (BP) continuous...

In this study, a novel high-precision positioning algorithm was proposed by using Visible Light Communication (VLC) with only a simple and single receiver. The received voltage-level difference with multi-level modulation was adopted as the input variable, in order to minimize the negative consequences of noise. Then, the relationship between the r...

Indoor air quality, temperature, and relative humidity affect the thermal comfort and health of the inhabitants. Therefore, monitoring these parameters is essential to prevent indoor air pollution and improve labor productivity. Most recently conducted research has used radio frequency (RF) wireless communications to monitor indoor environment. How...

High data transmission rates are desirable in an optical camera communication (OCC) system. In order to achieve this, a novel multilevel-intensity modulation (m-IM) scheme for a rolling-shutter (RS) based OCC is introduced in this paper. The proposed multilevel intensity signal is obtained by transmitting the signal pulse time faster than the camer...

Long-term exposure to radio frequency (RF) waves can have adverse effects on human health. It may causes bad effects especially to elderly people, children, and patients with weak immune systems. On the other hand, visible light communication (VLC) technologies that use light-emitting diode (LED) light source and photo detector to transmit and rece...

In this paper, an implementation of mobile-Visible Light Communication (mVLC) technology for clinical data transmission in home-based mobile-health (mHealth) rehabilitation system is introduced. Mobile remote rehabilitation program is the solutions for improving the quality of care of the clinicians to the patients with chronic condition and disabi...

The quality of a received signal is one of the most important factors to be considered when designing a receiver for visible light communication (VLC) systems. Therefore, it is necessary to evaluate the robustness of the VLC receiver circuit in low-signal-to-noise ratio (SNR) communication. The SNR is the quantity characterized by the ratio of the...

A wearable electroencephalogram (EEG) is a small mobile device used for long-term brain monitoring systems. Applications of these systems include fatigue monitoring, mental/emotional monitoring, and brain–computer interfaces. However, the usage of wireless wearable EEG systems is limited due to the risks posed by the wireless RF communication radia...

Noncontact electrocardiogram (ECG) measurement using capacitive-coupled technique is a very reliable long-term noninvasive health-care remote monitoring system. It can be used continuously without interrupting the daily activities of the user and is one of the most promising developments in health-care technology. However, ECG signal is a very smal...