• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.1009-1011
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• 2013

최근 U-헬스케어 서비스가 증가함에 따라 예방과 건강증진 등에 관심과 연구가 활발히 이루어지고 있다. 이러한 U-헬스케어에 사용되는 ECG, EMG, PPG EEG등이 스마트폰 기반의 휴대용 장비와 연동된 센서들의 연구 역시 활발히 진행 중이다. 일반적으로 PPG신호는 적외선센서를 이용하여 모세혈관의 혈중 헤모글로빈 농도 변화에 의한 맥파를 측정한다. PPG신호의 잡음을 제거하기 위해 필터를 사용하였다. 필터된 정보를 ADC하여 스마트폰으로 BlueTooth통신을 이용하여 전송한다. 최종적으로 스마트 디바이스에 PPG신호를 그린다. 제작결과 PPG아날로그 신호를 보는 것과 동일하게 스마트 디바이스에 그릴 수 있음을 보였다. 이후 PPG신호를 이용하여 혈관건강도 및 건강예방의 측정의 연구를 계속해서 한다.

• 센서학회지
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• 제25권5호
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• pp.354-364
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• 2016

Recently there have been extensive research activities on the development of on-the-spot detection technologies for bacteria from foods due to growing high demand for food safety. In particular, on-the-spot detection devices using biosensors with rapid, highly sensitive and multiplexed sensing capability are promising for portable or mobile applications. Firstly, issues related to on-the-spot bacteria detection are discussed. Then, detection methods for bacteria, types of biosensors depending on transducing principle and receptors, and platforms for integration of biosensors and signal readers are reviewed. Finally, prospects for development of on-the-spot detection devices are summarized.

• 한국측량학회지
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• 제32권3호
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• pp.185-190
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• 2014

The purpose of this research is to extract spectral reflectance characteristics of concretes through basic experiment on concrete specimens and site experiment on actual concrete structures using a field portable spectrometer and a VNIR hyperspectral sensor. A spectrometer (GER-3700) and a VNIR hyperspectral camera (AisaEagle VNIR Hyperspectral Camera) were utilized for extracting spectral characteristics of concrete specimens. Concretes normally show similar patterns that have correlation above 80%, while the high-strengthened concretes display very different results from the normal-strength concretes. We also made a certain conclusion in the laboratory experiment on concrete specimens that both the spectrometer and the VNIR camera vary in spectral reflectance depending on concrete strengths.

• 센서학회지
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• 제4권3호
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• pp.30-36
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• 1995

교통사고의 가장 큰 원인 중의 하나는 운전자의 각성수준의 저하이다. 적절한 각성수준을 갖는 운전자 만이 자동차를 안전하게 운전하여 목적지에 도착할 수 있다. 본 연구에서는 이러한 운전자의 각성도를 측정하기 위하여 피부 임피던스를 이용한 측정 시스템을 구성하고 이를 이용하여 6인의 피검자의 피부 임피던스의 변화와 뇌파를 동시에 측정하여 각성수준의 변화에 따른 세 측정 요소간의 상관관계를 검토하고 피부임피던스 지표를 구하였으며 측정에 따른 문제점들을 분석하여 운전자의 각성도 측정 및 평가와 모니터 개발을 위한 기초적인 연구를 하였다.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.106-111
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• 2020

In this paper, we propose the non-contact gesture recognition system and algorithm using proximity-based sensors. The system uses four IR receiving photodiode embedded on a single chip and an IR LED for small area. The goal of this paper is to use the proposed algorithm to solve the problem associated with bringing the four IR receivers close to each other and to implement a gesture sensor capable of recognizing eight directional gestures from a distance of 10cm and above. The proposed system was implemented on a FPGA board using Verilog HDL with Android host board. As a result of the implementation, a 2-D swipe gesture of fingers and palms of 3cm and 15cm width was recognized, and a recognition rate of more than 97% was achieved under various conditions. The proposed system is a low-power and non-contact HMI system that recognizes a simple but accurate motion. It can be used as an auxiliary interface to use simple functions such as calls, music, and games for portable devices using batteries.

• 대한임베디드공학회논문지
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• 제13권2호
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• pp.73-81
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• 2018

This paper describes a device platform which the blind can wear to keep path and to get surrounding information during their independent walking. Compared to the existing technologies, the proposed device could be used indoors and outdoors, and maps need not be provided in advance. It is composed of a glasses type device equipped with image sensors, and a portable device that analyzes sensor data for sighted guiding. RGB images and depth images are extracted to generate a walking map based on feature points. It also can cope with the risk of collision with bollard, color cone by applying vertical obstacle detection technology based on floor detection.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.783-788
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• 2005

Detection of small leakage current is the most important technique in arrester diagnosis. Various types of leakage current detector have been commercialized, but they are not available for the railway arresters including voltage harmonics, and do not furnish enough information needed for arrester diagnosis. This paper describes the development of a leakage current detector which is suitable for the railway arresters. The detector is consisted of a sensor unit with amplifier, an optical linker and main analyzer. Frequency bandwidth and measuring range of the detector is 9[Hz]$\~$850[Hz] and 50[uA]$\~$5[mA], respectively.

• 한국분무공학회지
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• 제9권4호
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• pp.67-76
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, reasonable cost, robustness, and ease of use. In addition, diode lasers we fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.920-923
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• 2003

An wearable electrocardiogram (ECG) monitoring system is a widely used non-invasive diagnostic tool for ambulatory patient who may be at risk from latent life-threatening cardiac abnormalities. In this paper, we have a portable ECG monitoring system with conductive fiber which was characterized by the small-size and the low power consumption. The system consists of conductive fibers, one-chip microcontroller, ECG preprocessing circuit, and monitoring software to be able to record and analyze in PC. ECG preprocessing circuit is made of pre-amplifier with gain of 10, band-pass filter with bandwidth of 0.5-120Hz and 2.5V offset circuit for A/D conversion. ECG signals obtained by sensor are included with corrupted noises such as a baseline wandering, 60 Hz power noise and interference noise by body movement. For cancellation corrupted noises in signals obtained by conductive fiber, we used the wavelet decomposition of wavelet transforms in MATLAB toolbox.

• 통합자연과학논문집
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• 제2권4호
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• pp.275-279
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• 2009

Recently, number of studies for porous silicon (PSi) have been investigated by many researchers. Multistructured porous silicon such as a distributed Bragg reflector (DBR) PSi, has been a topic of interest, because of its unique optical properties. DBR PSi were prepared by using an electrochemical etch of $P{^+}{^+}$-type silicon wafer with resistivity between 0.1 and $10m{\Omega}cm$. The electrochemical etch with square wave current density results in two different refractive indices in the porous layer. In this work, DBR porous silicon chips for a simple and portable organic vapor-sensing device have fabricated. The optical characteristics of DBR PSi have been investigated. DBR porous silicon have been characterized by FT-IR and Ocean optics 2000 spectrometer. The device used DBR PSi chip has been demonstrated as an excellent gas sensor, showing a great senstivity to organic vapor at room temperature.