Kyeong-Seop Kim

Development of Smart Toothbrush Monitoring System for Ubiquitous Healthcare

The design of an intelligent toothbrush, capable of monitoring brushing motion, orientation through the grip axis, during toothbrushing is described. Inappropriate tooth-brushing styles, even in adults, sometimes cause dental problems, cavities, gingivitis, etc. This smart system provides user to monitor his or her brushing pattern using accelerometer and magnetic sensors for evaluation of toothbrushing style. Directional information of toothbrush with respect to the earths magnetic field and activity data were measured by a miniaturized low-power micro-controller, MSP430 and transmitted to personal computer by 2.4 GHz radio transmitter, nRF2401. A personal computer provides an on-line display of activity and orientation measurements during toothbrushing. The signal trace is then analyzed to extract clinically relevant information. This preliminary study showed that the proposed monitoring system was conceived to aid dental care personnel in patient education and instruction in oral hygiene regarding brushing style

Application for the wearable heart activity monitoring system : Analysis of the autonomic function of HRV

The wearable patch-style heart activity monitoring system (HAMS) which was used for recording ECG signal in this study is self-developed. This electrode design helps the non-restricted, non-aware and non-invasive ECG measurement. The modified bipolar electrode is convenient in use because it is designed for easy attachment and detachment with ECG measuring module by snap button. Besides, it minimizes EMI by removing the cables. In the same subjects who were exposed under stress and non-stress, the questionnaire was given out, the amount of the stress hormone was measured by blood test and the ECG signal was recorded. Through the analysis of ECG signal which is measured with wearable patch-style HAMS, the parameter highly related with mental stress were extracted from frequency and time domain. These parameters were certified as the meaningful factor after correlation analysis on the results from questionnaire and stress hormone test. Also, it is proved that the availability of wearable patch-style heart monitoring system is efficient as health monitoring system in any places and occasion.

Automated quantification of retinal nerve fiber layer atrophy in fundus photograph

Quantitative analysis of the retinal nerve fiber layer (RNFL) defect is prerequisite in the early detection and management of glaucoma. A new automatic quantification method to evaluate the degree of RNLF defect has been proposed in this paper. Simple image processing technique is applied to locate optic disc and intensity of the pixels around optic disc is plotted. The area with RNFL defect can be easily determined by comparing the intensity plot of the RNFL and the first derivative of the intensity plot. Through analysis of the plot, thickness of RNFL also can be postulated.

A Real Time QRS Detection Using Delay-Coordinate Mapping for the Microcontroller Implementation

AbstractIn this article, we propose a new algorithm using the characteristics of reconstructed phase portraits by delay-coordinate mapping utilizing lag rotundity for a real-time detection of QRS complexes in ECG signals. In reconstructing phase portrait the mapping parameters, time delay, and mapping dimension play important roles in shaping of portraits drawn in a new dimensional space. Experimentally, the optimal mapping time delay for detection of QRS complexes turned out to be 20 ms. To explore the meaning of this time delay and the proper mapping dimension, we applied a fill factor, mutual information, and autocorrelation function algorithm that were generally used to analyze the chaotic characteristics of sampled signals. From these results, we could find the fact that the performance of our proposed algorithms relied mainly on the geometrical property such as an area of the reconstructed phase portrait. For the real application, we applied our algorithm for designing a small cardiac event recorder. This system was to record patients’ ECG and R–R intervals for 1 h to investigate HRV characteristics of the patients who had vasovagal syncope symptom and for the evaluation, we implemented our algorithm in C language and applied to MIT/BIH arrhythmia database of 48 subjects. Our proposed algorithm achieved a 99.58% detection rate of QRS complexes.

Interactive toothbrushing education by a smart toothbrush system via 3D visualization

The very first step for keeping good dental hygiene is to employ the correct toothbrushing style. Due to the possible occurrence of periodontal disease at an early age, it is critical to begin correct toothbrushing patterns as early as possible. With this aim, we proposed a novel toothbrush monitoring and training system to interactively educate on toothbrushing behavior in terms of the correct brushing motion and grip axis orientation. Our intelligent toothbrush monitoring system first senses a users brushing pattern by analyzing the waveforms acquired from a built-in accelerometer and magnetic sensor. To discern the inappropriate toothbrushing style, a real-time interactive three dimensional display system, based on an OpenGL 3D surface rendering scheme, is applied to visualize a subjects brushing patterns and subsequently advise on the correct brushing method.

A Simple Optical Angular Sensors to Measure the Human Joint Angle

Medical practioners usually measure dorsiflection of the human joint angle for medical assessment purpose. In order to measure the joint angle, a more or less standard mechanical or electro-mechanical goniometer is used. But mechanical construction has many problems. This research is originated from the lack of user-friendly, versatile and not expensive apparatus which are commercially available. In this paper, we present new design concepts of goniometer utilizing the light refraction characteristics of optical fiber in order to measure angular displacement of the human joints. In order to form an asymmetrical beam profile at the end of fiber tips, we cut the end of fiber tip at an angle of 35 degrees. Phototransistor is used to measure beam intensity as a function of optical fiber angle with respect to optical axis of fiber. Thus the sensed signal represented an indirect measure of curvature angle. The result showed that asymmetrical beam profile provide wider linear relationship than symmetrical one. Eventually, overall performance of the proposed sensor is quite suitable for measurement of the human joint angle

Toothbrushing Region Detection Using Three-Axis Accelerometer and Magnetic Sensor

Due to the possible occurrence of periodontal disease at an early age, it is important to have proper toothbrushing habits as early as possible. With this aim, the feasibility and concept of a smart toothbrush (ST) capable of tracing toothbrushing motion and orientation information was suggested. In this study, we proposed the advanced ST system and brushing region classification algorithm. In order to trace the brushing region and the orientation of a toothbrush in the mouth, we required the absolute coordinate information of ST. By using tilt-compensated azimuth (heading) algorithm, we found the inclination and orientation information of the toothbrush, and the orientation information while brushing inner tooth surfaces showed specific heading features that could be reliably discriminated from other brushing patterns. In order to evaluate the feasibility of clinical usage of the proposed ST, 16 brushing regions were investigated by 15 individual healthy subjects. The proposed ST system demonstrated 97.1%(±0.91) of the region detection accuracy and 15 brushing regions could be classified. This study also showed that the proposed ST system may be helpful for dental care personnel in patient education and instruction for oral hygiene regarding brushing habits.

Tooth brushing Pattern Classification using Three-Axis Accelerometer and Magnetic Sensor for Smart Toothbrush

The concept of intelligent toothbrush, capable of monitoring brushing motion, orientation through the grip axis, during toothbrushing was suggested in our previous study. In this study, we describe a tooth brushing pattern classification algorithm using three-axis accelerometer and three-axis magnetic sensor. We have found that inappropriate tooth brushing pattern showed specific moving patterns. In order to trace the position and orientation of toothbrush in a mouth, we need to know absolute coordinate information of toothbrush. By applying tilt-compensated azimuth (heading) calculation algorithm, which is generally used in small telematics devices, we could find the inclination and orientation information of toothbrush. To assess the feasibility of the proposed algorithm, 8 brushing patterns were preformed by 6 individual healthy subjects. The proposed algorithm showed the detection ratio of 98%. This study showed that the proposed monitoring system was conceived to aid dental care personnel in patient education and instruction in oral hygiene regarding brushing style.

A novel design of thermal anomaly for mammary gland tumor phantom for microwave radiometer

Microwave radiometry is a spectral measurement technique for resolving electromagnetic radiation of all matter whose temperature is above absolute zero. This technique utilizes the electromagnetic noise field generated by a thermal volume similar to the mechanism existing in biological tissues. One particular application of microwave radiometry is for analyzing temperature differentials inside the human body to detect and diagnose some crucial pathological conditions. For the general evaluation of a microwave radiometer, we propose a new type of phantom containing a mammary gland tumor imitator by considering biological heat diffusion effects propagated by a real tumor. Theoretical research on human tumors revealed the fact that the temperature distribution of tissues around a tumor displayed Gaussian statistics. To comply with the physiological property of the real tumor, we built a mammary gland tumor imitator composed of two parts (pseudotumor and thermal anomaly) and observed its temperature distribution when it was placed inside a phantom. Our results showed that the thermal properties of the tumor imitator agreed well with heat-transfer properties of a real tumor and that a proportional linear relationship existed between the location of the tumor imitator and the intensity of radiometer measurements. From this relationship, we could also estimate several parameters related to our phantom, such as the minimum detectable size and maximum detectable depth of a tumor imitator.

Removal of baseline wandering in ECG signal by improved detrending method

The very first step to process electrocardiogram (ECG) signal is to eliminate baseline wandering interference that is usually caused by electrode-skin impedance mismatch, motion artifacts due to a patients body moment or respiratory breathing. A new method is thus suggested to remove baseline wandering in ECG by improving the detrending method that was originally proposed for eliminating slow non-stationary trends from heart rate variability (HRV). In our proposed method, a global trend is estimated in terms of baseline wandering by merging the local trend based on an ECG segment that represents a part of the ECG signal. The experimental results show that the improved detrending method can efficiently resolve baseline wandering without distorting any morphological characteristic embedded in the ECG signal in no time delay manner.