• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.10
• /
• pp.2205-2210
• /
• 2009

In this paper, the proposed method is a denoising technology by tangent curve interpolation of zero points. The problem of the hard threshold method is improved by the proposed method. The quantity of time fluctuation of the electromagnetic signal as the quantity of electric fluctuation of the natural world or the curve of motion waveform of the fast movement of human extracted using virtual reality is, in fact, complex. Therefore it is important to decide exactly the signal properties as the inflection point for observation signal. In particular, it is necessary to extract the properties after denoising, since the measurement signal of the natural world include some noises. It shows that the noise of the inflection point signal with noise II, noise factor 5, is eliminated by the proposed method, and the result of SNR for the signal is improved 3.4dB than that by the conventional hard threshold.

• Journal of Biomedical Engineering Research
• /
• v.23 no.2
• /
• pp.109-117
• /
• 2002

Electrogastrography(EGG) is a noninvasive method for measuring gastric electrical activity on the abdomen resulting from gastric muscle. EGG signals have a very low frequency range (0.0083 ~0.15 Hz) and extremely low amplitude(10~100 uV). Consequently, EGG signal is easily influenced by other noises. Both finite impulse response(FIR) and infinite impulse response (IIR) filters need high orders or have phase distortions for passing very narrow bandwidth of the EGG signal. In this study, we decomposed EGG signals using a wavelet multiresolution method with Daubechies mother wavelet. The EGG signals were decomposed to seven levels. We reconstructed signal by summing the decomposed signals from level four to seven. To evaluate the performance of the wavelet multiresolution filter(WMF) with simulated EGG signal using two kinds of FIR and four kinds of IIR filters., we used two indices; signal to noise ratio(SNR) and reconstruction squared error(RSE). The SNR of WMF had 9.5, 6.9, and 4.7 dB bigger than that of the other filters at different noise levels, respectively. Also, The RSE of WMF had $1.22{\times}10^6, 1.16{\times}10^6, 1.02{\times}10^6$ smaller than that of the other filters at different noise levels, respectively. The WMF performed better in the SNR and RSE than two kinds of FIR and four kinds of IIR filters.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2009.11a
• /
• pp.87-90
• /
• 2009

본 연구는 HMD(Head Mounted Display), 적외선 카메라, 웹 카메라, 데이터 글러브, 그리고 생리신호 측정 센서를 이용한 증강현실 게임 플랫폼 설계를 목적으로 하고 있다. HMD 는 사용자의 머리의 움직임을 파악하고, 사용자에게 가상 물체를 디스플레이화면에 제공한다. 적외선 카메라는 HMD 하단에 부착하여 사용자의 시선을 추적한다. 웹 카메라는 HMD 상단에 부착하여 전방 영상을 취득 후, 현실영상을 HMD 디스플레이를 통하여 사용자에게 제공한다. 데이터 글러브는 사용자의 손동작을 파악한다. 자율신경계반응은 GSR(Galvanic Skin Response), PPG(PhotoPlethysmoGraphy), 그리고 SKT(SKin Temperature) 센서로 측정한다. 측정된 피부전기반응, 맥파, 그리고 피부온도는 실시간 데이터분석을 통하여 집중 정도를 파악하게 된다. 사용자의 머리 움직임, 시선, 그리고 손동작은 직관적 인터랙션에 사용되고, 집중 정도는 직관적 인터랙션과 결합하여 사용자의 의도파악에 사용된다. 따라서, 본 연구는 멀티모달 인터랙션을 이용하여 직관적 인터랙션 구현과 집중력 분석을 통하여 사용자의 의도를 파악할 수 있는 새로운 증강현실 게임 플랫폼을 설계하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.9
• /
• pp.3435-3440
• /
• 2010

Unlike the electric method capable of checking only product defect, the real time optical metrology is suggested for measuring and visualizing vibration with respect to position of surface acoustic wave in RF device. The measuring limits and conditions for surface acoustic wave is given, and the interference and diffraction due to RF signal are analyzed by optical interpretation. A single mode laser and a 105MHz-center-frequency repeater filter were employed for experiments and theoretical analysis. In this paper, the optical metrology providing visual energy distribution and real time inspection for surface acoustic wave is proposed for development of high quality multi-service and multi-frequency RF module.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.6
• /
• pp.109-114
• /
• 2013

The biological active points (BAP) are known as low resistance spots or good electro-permeable points. In this paper, a new method for BAP detection using the bio-impedance measurement system based on the adaptive frequency tracking filter (AFTF) and the transition event detector is presented. Also, the microcontroller process continuous time demodulation of the modulated signal by multi frequency components using the AFTF. The transition event detector based on the phase space method is applied about each frequency using the BAP equivalent model which is proposed.

• Journal of the Korean Magnetics Society
• /
• v.22 no.2
• /
• pp.45-48
• /
• 2012

Feed-back type 3-axis flux-gate magnetometer using Co-based amorphous ribbon (Metglass$^{(R)}$2714A) was constructed in this work. Measuring range of magnetic field and frequency were ${\pm}100\;{\mu}T$ and dc~10 Hz respectively. For the interface to computer, microcontroller and 24 bit ADC (Analog to Digital Converter) were employed and resolution of digital output was 0.1 nT. Magnetometer noise of analog output was 5 pT/$\sqrt{Hz}$ at 1 Hz. Digital output of the magnetometer showed linearity of $1{\times}10^{-4}$ and the offset drift was smaller than 0.2 nT during 1 h.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.1
• /
• pp.78-82
• /
• 2019

This paper addressed the spectrum of ultrasonic waves produced by arc and/or coronal discharge inside the switchboard. Portable ultrasound sensors are useful for detecting discharge phenomena, such as coronal means in electrical systems. However, a typical handheld ultrasound detector has a disadvantage of determining the type of problem by listening to the sound characteristics and predicting the results, as a result of the determination of whether a discharge is present. Therefore, a new method of analysis is required to distinguish ultrasonic characteristics. In this paper, we published an ultrasound analysis case study to visualize the sound of ultrasonic waves measured with ultrasonic sensors. From the results of the experiment, it was possible to detect coronal discharge and serial arc discharge without interference by the ultrasonic detection system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.559-562
• /
• 2017

In city, tracing of power transmission lines is difficult due to compound installation of overhead and underground lines, transposition, bad view caused by trees or big buildings. It is hard problem for electrical technician on site to trace power transformers or power lines to serve customers in 3 phase -4 wires power distribution systems. It is necessary that the correct and fast tracing method is required for load balancing among distribution lines. Old technology use to trace off-lines with high power impulse injection. Our proposed method use to trace live lines with very small power high frequency signal injection. Typical power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. Two end communication terminals are required to be synchronized between them for determination on electrically same phases. Challenging issue is to achieve synchronization without GPS providing synchronizing time. A novel power transformer and wire identification system is designed and implemented. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.

• Journal of IKEEE
• /
• v.19 no.2
• /
• pp.237-243
• /
• 2015

Recently, eight out of ten people have smartphone in Korea. Also, many applications of smartphone have increased. So, smartphone addiction has become a social issue. Especially, many people in smartphone addiction can't control themselves. Sometimes they don't realize that they are smartphone addiction. Many studies, mostly surveys, have been conducted to diagnose smartphone addiction, e.g. S-measure. In this paper, we suggest how to detect smartphone addiction based on ECG and Eye Gaze. We measure the signals of ECG from the Shimmer and the signals of Eye Gaze from the smart eye when the subjects see the emotional video. In addition, we extract features from the S-transform of ECG. Using Eye Gaze signals(pupil diameter, Gaze distance, Eye blinking), we extract 12 features. The classifier is trained using Random Forest. The classifiers detect the smartphone addiction using the ECG and Eye Gaze signals. We compared the detection results with S-measure results that surveyed before test. It showed 87.89% accuracy in ECG and 60.25% accuracy in Eye Gaze.

• Korean Journal of Optics and Photonics
• /
• v.13 no.3
• /
• pp.251-257
• /
• 2002

The measuring resolution and speed for wavefronts are important to improve the performance of an adaptive optics system. In this paper, we propose a fast measuring algorithm with high resolution in the Shack-Hartmann wavefront sensor for an adaptive optics system. We designed ground isolated electrical devices whose differential data signals are used to control the deformable mirror and tip/tilt mirror for robust control. The conventional mass centroid algorithm in the Shack-Hartmann sensor to measure wavefront has been widely used and provided good measurement results. In this paper, the proposed fast measuring algorithm for measuring the wavefront combines the conventional mass centroid algorithm with a weighting factor. The weighting factor is a real value estimating the real center of mass in a wavefront spot image. This proposed wavefront measuring algorithm provided fast measurement results with high resolution from experimental tests.