• Science of Emotion and Sensibility
• /
• v.22 no.3
• /
• pp.55-64
• /
• 2019

Stroke is a health problem experienced by many elderly people around the world. Stroke has a devastating effect on quality of life, causing death or disability. Hemiplegia is clearly an early sign of a stroke and can be detected through patterns of body balance and gait. The goal of this study was to determine various feature vectors of foot pressure and gait parameters of patients with stroke through the use of a wearable sensor and to compare the gait parameters with those of healthy elderly people. To monitor the participants at all times, we used a simple measuring device rather than a medical device. We measured gait data of 220 healthy people older than 65 years of age and of 63 elderly patients who had experienced stroke less than 6 months earlier. The center of pressure and the acceleration during standing and gait-related tasks were recorded by a wearable insole sensor worn by the participants. Both the average acceleration and the maximum acceleration were significantly higher in the healthy participants (p < .01) than in the patients with stroke. Thus gait parameters are helpful for determining whether they are patients with stroke or normal elderly people.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.6
• /
• pp.922-928
• /
• 2006

An absolute absorption cross section of benzene was measured with a spectrometer system including a mono-chrometer and a grating in the wavelength region of $240{\sim}280nm$ under the atmospheric pressure and room temperature in the laboratory. A certificated reference benzene gas ($98{\mu}mol/mol$ in $N_2$) was used to measure its absorption cross section. A 710 mm cell with a quartz window and a 150 W Xe arc lamp were employed. The magnitude of absorption cross section of $1.41{\times}10^{-18}cm^2$ was lower than that of the reference spectra ($2.5{\times}10^{-18}cm^2$) of high resolution spectrometer, Total measurement uncertainty was estimated to be 4.0%.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.3
• /
• pp.323-329
• /
• 2011

Certified reference materials (CRMs) have been used to calibrate surface profilers for reliable measurements. In this paper, we present a newly designed step height CRM which has a step height pattern with two different widths and various special patterns for checking radial magnification, distortion of optical viewing systems, etc. Especially, it could be useful for multi-probe inspection instruments in the manufacturing lines. The fabrication was done by conventional optical lithography and dry etching process with optimized conditions. To verify the step height values, a white-light scanning interferometer was used with objective lenses having magnification of $10{\times}$ and $100{\times}$. CRMs with nominal step heights of $0.5\;{\mu}m$, $1\;{\mu}m$, $3\;{\mu}m$, $5\;{\mu}m$, $7\;{\mu}m$, and $10\;{\mu}m$ were fabricated and the uniformity of these CRMs was evaluated to be less than 3 nm ($1{\sigma}$).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.373-373
• /
• 2012

염료 감응형 태양전지는 기존 Si 기반 PN접합 무기 태양전지에 비해서 경제적이다. 하지만 그 에너지 변환 효율은 아직까지 세계 최고 수준이 10%밖에 도달하지 못하였다. 그래서 다양한 방식의 효율개선 연구가 활발히 진행되고 있는 실정이다. 본 연구에서는 진공원자층증착(ALD)를 이용하여 Core-shell 구조의 $TiO_2$층 위에 아주 얇고 균일한 $Al_2O_3$ (알루미나) 산화막을 입혔다. 이를 통해서 염료감응형 태양전지의 에너지 변환 효율을 향상시켰다. 본 연구에서는 진공원자층증착(ALD)기술을 이용한 $Al_2O_3$ (알루미나) 산화막의 증착조건에 따른 염료감응태양전지의 효율 개선 매커니즘에 대해서 고찰하였다.

• Proceedings of the KIEE Conference
• /
• 2009.04b
• /
• pp.3-5
• /
• 2009

교류 자기장의 정밀측정, 자기장 측정기의교정 및 관련 시험 등 을 지원하기 위해 교류자기장 표준장치를 개발하였다. 주파수에 따른 확장분확도(expanded uncertainty, 2 $\sigma$)는 1 MBz 이하에서 0.16 %, 1 kHz $\sim$ 5 kHz 에서 0.26 %, 5 kHz $\sim$ 20 kHz에서 0.44 % 이었다. 측정결과에 대한 국제적 신뢰성 및 상호인증을 확보하기 위하여 핵심측정표준 국제비교(international key comparison)에 참여하였으며, 또한 측정능력, 교정 및 시험방법 등에 대한 국제적 전문가로부터 평가(peer review)를 수감하였다. 따라서 한국표준과학연구원 (KRISS)에서 교정 및 측정한 결과에 대해서는 국제적 상호인증을 받을 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.59-62
• /
• 2005

Small force measurements ranging from 1 pN to $100{\mu}N$, we call it Nano Force, become the questions of common interests of biomechanics, nanomechanics, material researches, and so on. However, unfortunately, quantitative and accurate force measurements have not been taken so far. This is because there ,are no traceable force standards and a calibration scheme. This paper introduces a quantitative force metrology, which provides traceable link to SI (International Systems of Units). We realize SI traceable force ranging from 1 nN to $100{\mu}N$ using an electrostatic balance and disseminate it through transfer standards, which are self-sensing cantilevers that have integrated piezoresistive strain gages. We have been built a prototype electrostatic balance and Nano Force Calibrator (NFC), which is an AFM cantilever calibration system. As a first experiment, we calibrated normal spring constants of commercial AFM cantilevers using NFC. Calibration results show that the spring constants of them are quite differ from each other and nominal values provided by a manufacturer (up to 240% deviation).

• Journal of Biomedical Engineering Research
• /
• v.43 no.3
• /
• pp.147-152
• /
• 2022

This research is to measure real-time temperature distribution inside a tissue-mimicking phantom for the safety and effectiveness evaluations of focused ultrasound (FUS) device capable of linear scanning stimulation. Since the focusing area of the FUS stimulation device is smaller than diameter of conventional thermal probe and keeps moving, it is impossible to monitor temperature distribution inside the phantom. By using the phantom with a thin film temperature sensor array inserted, real-time temperature change caused by the FUS device was measured. The translation of the measured temperature peak was also tracked successfully. The present phantom had been experimentally proven to be applicable to validate the performance and safety of the therapeutic ultrasound devices.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.3 no.1
• /
• pp.28-32
• /
• 1992

The site attenuation for vertical polarization was theoretically calculated using EMF(electro- Motive force) method and measured for 3-m method in the KRISS semi-anechoic chamber. Agreement within .+-. 4 dB has been obtained between measured and calculated values in the frequency range of 30 MHz to 1000 MHz except 250 MHz and around 100 MHz.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.368-368
• /
• 2004

• 한국가스학회:학술대회논문집
• /
• 1999.09a
• /
• pp.100-107
• /
• 1999