• 한국정보통신학회논문지
• /
• 제15권4호
• /
• pp.905-912
• /
• 2011

본 논문에서는 실시간 안압 모니터링을 위한 안압 센서와 안압에 따른 안압 센서의 공진 주파수를 검출 할 수 있는 외부 코일을 설계 및 구현 하였다. 안압 센서는 3-D EM 시뮬레이션을 통하여 설계 하였고, MEMS 기반 기술로 구현 되었다. 측정 결과로서, 안압 센서의 공진 주파수는 외부 코일의 공진 주파수에 비하여 낮아야 하며, 안압 센서의 공진 주파수가 외부 코일의 공진 주파수에 근접 하게 위치 할 때, 위상 변화량이 높아짐을 확인 하였다. 또한, 안압 센서는 외부 코일과의 거리에 따라 최대위상 변화가 발생하는 지점이 불변하여야 하는데, 설계된 안압 센서는 외부 코일과의 거리가 변화 할 때, 최대위상 변화량 자체는 변화 하지만, 최대위상 변화가 발생하는 지점이 동일함을 확인 하였다.

• 센서학회지
• /
• 제23권6호
• /
• pp.409-415
• /
• 2014

We had presented an inductive type intraocular pressure sensor (L-sensor) in previous work. The distance between a micro coil and a ferrite on the membrane was modulated by pressure, and as a result the inductance and resonant frequency were changed. However, L-sensor has some problems to implant in eyes. First problem is low sensitivity. When L-sensor was implanted in rabbit's eyes, resonant frequency of L-sensor was very hard to detect. Second problem is biocompatibility. Size of L-sensor is $6{\times}7{\times}1.2mm$. When L-sensor was implanted in the eyes, it caused the inflammation. Therefore, this study suggests an inductive and capacitive type IOP sensor (LCsensor). The sensitivity of the LC-sensor 27.3 kHz/mmHg under 60mmHg. It is much larger than 14 kHz/mmHg of the L-sensor. And the size of LC-sensor is 47% smaller than L-sensor. After 2 weeks from the implantation of LC-sensor into rabbit eyes, we measured the changes of resonant frequency of LC-sensor according to increased IOP by Balanced Salt Solution (BSS) injection. As a result, the sensitivity of LC-sensor in in vivo test is 25 kHz/mmHg. That is similar to the sensitivity of in vitro test.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제13권4호
• /
• pp.355-360
• /
• 2013

A wireless intraocular (IOP) pressure sensor based on micro electro mechanical system (MEMS) technology is proposed. The proposed IOP sensor uses variable inductance according to the external pressure. The proposed sensor is composed of two flexible membranes: a ferrite bottom part, an inductor, and a capacitor. The inductance of the sensor varies according to the external pressure. The resonance frequency of the sensor is also varied, and this frequency is detected using an external coil. The external coil is designed with an FR-4 printed circuit board. The feasibility of the proposed sensor structure using variable inductance to detect the external pressure is successfully demonstrated.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.103.6-103
• /
• 2001

Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure) in the eye. High IOP is caused by the aqueous humor which is produced consistently but not drained due to the malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are some methods to treat glaucoma, Among these, the use of implants is increasing in these days due to many problems in other methods. However, conventional implants are passive implants and have critical disadvantage. Therefore, it is needed to develop a new implant using MEMS structure which is capable of controlling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper the valve actuator is considered. We make experiments and simulations with the fabricated ...

• 대기
• /
• 제19권2호
• /
• pp.213-226
• /
• 2009

In order to investigate the characteristics of Changma over the Korean peninsula, KEOP-2007 IOP (Intensive Observing Period) was conducted from 15 June 2007 to 15 July 2007. KEOP-2007 IOP is high spatial and temporal radiosonde observations (RAOB) which consisted of three special stations (Munsan, Haenam, and Ieodo) from National Institute of Meteorological Research, five operational stations (Sokcho, Baengnyeongdo, Pohang, Heuksando, and Gosan) from Korea Meteorological Administration (KMA), and two operational stations (Osan and Gwangju) from Korean Air Force (KAF) using four different types of radiosonde sensors. The error statistics of the sensor of radiosonde were investigated using quality control check. The minimum and maximum error frequency appears at the sensor of RS92-SGP and RS1524L respectively. The error frequency of DFM-06 tends to increase below 200 hPa but RS80-15L and RS1524L show vice versa. Especially, the error frequency of RS1524L tends to increase rapidly over 200 hPa. Systematic biases of radiosonde show warm biases in case of temperature and dry biases in case of relative humidity compared with ECMWF (European Center for Medium-Range Weather Forecast) analysis data and precipitable water vapor from GPS. The maximum and minimum values of systematic bias appear at the sensor of DFM-06 and RS92-SGP in case of temperature and RS80-15L and DFM-06 in case of relative humidity. The systematic warm and dry biases at all sensors tend to increase during daytime than nighttime because air temperature around sensor increases from the solar heating during daytime. Systematic biases of radiosonde are affected by the sensor type and the height of the sun but random errors are more correlated with the moisture conditions at each observation station.

• 한국자동차공학회논문집
• /
• 제22권5호
• /
• pp.126-135
• /
• 2014

This paper describes the development and verification of control algorithms for V2X and environmental sensor integrated intersection support and safety systems. The objective of the research is to develop core technologies for effective fusion of V2X and environmental sensors and to develop new safety function for intersection safety. One of core technologies is to achieve the improvement of GPS accuracy, and the other is to develop the algorithm of a vehicle identification which matches all data from V2X, vehicle sensors and environmental sensors to specific vehicles. A intersection optimal pass (IOP) algorithm is designed based on these core technologies. IOP recommends appropriate speed to pass the intersection in the consideration of traffic light signal and preceeding vehicle existence. Another function is developed to prevent a collision avoidance when car crash caused by traffic violation of surrounding vehicles is expected. Finally all functions are implemented and tested in three test vehicles. It is shown that IOP can support convenient and comfortable driving with recommending optimal pass speed and collision avoidance algorithm can effectively prevent collision caused by traffic sign violation of surrounding vehicles.

• 대한기계학회논문집A
• /
• 제25권5호
• /
• pp.805-815
• /
• 2001

Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure). High IOP is caused by the aqueous humor which is produced consistently but not drained due to malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are three methods to treat glaucoma-using medicines, surgical operation, and using implant device. The first and second methods are not long acting, so the use of implants is increasing in these days in order to drain out the aqueous humor compulsory. However, though conventional implants have a capability of pressure regulation, they cannot maintain IOPs desired for different patients, and too much aqueous humor are usually drained, to cause hypotony. To solve these problems, it is needed to develop a new implant which is capable of controling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper, firstly, we make an analysis of the operation of a conventional implant using a bond graph and show defects and limitations of the conventional valve analytically. Secondly, we design and analyze a valve actuator considering actuation principles, resistance elements, control methods, and energy sources focused on power saving problem. Finally, using simulations the possibility of the proposed valve actuator is investigated.

• 대한원격탐사학회지
• /
• 제26권2호
• /
• pp.175-188
• /
• 2010

세계 최초로 정지 상태로 해색을 관측하는 정지궤도해색탑재체(GOCI, Geostationary Ocean Color Imager) 값의 보정을 위해서는 기존의 방법이 아닌 새로운 방법이 요구된다. 본 연구에서는 GOCI의 특별한 특성에 맞는 새로운 대기보정 방법과 양방향성 광반사 분포함수(BRDF, Bidirectional Reflectance Distribution Function) 보정 방법을 소개하고자 한다. GOCI의 대기보정을 위해서 스펙트럼 형태 조화기법(SSMM, Spectral Shape Matching Method)과 Sun Glint Correction Algorithm(SGCA)을 개발하였고, BRDF 보정을 위하여 해수의 고유광특성(IOP, Inherent Optical Property) 값을 이용하는 새로운 방법을 개발하였다. 각 방법은 한반도 주변 해역을 관측한 Sea Viewing Wide Field-of-view Sensor(SeaWiFS) 위성영상을 이용하여 적용하였다. 클로로필 농도 분포 영상을 만들어 본 결과 기존의 방법으로 얻기 어려웠던 탁도높은 해역과 에어로졸의 영향을 많이 받는 지역에서 보다 정확한 자료를 얻을 수 있었다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
• /
• pp.49-52
• /
• 2007

This study uses empirical method to estimate absorption coefficient of colored dissolved organic matter $(a_{dom})$ from GOCI satellite data with the relationship between band ratio of remote sensing reflectance $(R_{rs})$ and $a_{dom}$. For development of $a_{dom}$ estimation algorithm, the used data is in-situ data about ocean optical properties in the around seawater area of the Korean Peninsula during 1998 - 2005. The relationship of $R_{rs}$(412)/$R_{rs}$(555), $R_{rs}$(443)/$R_{rs}$(555), $R_{rs}$(490)/$R_{rs}$(555), $R_{rs}$(510)/$R_{rs}$(555) and $a_{dom}$(412) showed $R^2$ values of 0.707, 0.707, 0.597 and 0.552, respectively. The spectrum of $a_{dom}({\lambda})$ is shape of exponential function $a_{dom}({\lambda})$ value decreases with increasing wavelength. For estimation of $a_{dom}$ from satellite data, we developed an algorithm from the relationship of $a_{dom}$(412) and $R_{rs}$(412)/$R_{rs}$(555). This algorithm was employed on SeaWiFS imagery to estimate $R_{rs}$(412) in the South Sea, East Sea, Yellow Sea and northern East China Sea areas. Also, SeaDAS-derived $a_{dg}$(412) from same SeaWiFS imagery, These $a_{dg}$(412) was then compared with in-situ and empirical-algorithm-derived $a_{dom}$(412), but these values were different. We think two points that such different values are caused by discrepancy related to failure of standard atmospheric correction scheme, the other are caused by error related to definition of $a_{dom}$(412) and $a_{dg}$(412).

• 대한원격탐사학회지
• /
• 제30권1호
• /
• pp.47-59
• /
• 2014

화산재입자의 굴절률과 산란 같은 고유 광학 특성으로 결정되는 분광학적 신호는 원격탐사 센서를 통하여 측정될 수 있지만, 화산 폭발 이후 생성된 화산재입자의 성분에 대한 굴절률에 관한 정보는 매우 제한적이었다. 따라서, 화산재입자의 원격탐사의 강건성을 개선하기 위하여 화산재입자와 복사전달 과정의 상호작용에 대한 정확한 이해가 필요하다. 본 연구에서는 화산재 주요 성분으로 알려진 화산성 안산암과 부석에 대한 입자 소산계수, 산란 위상함수, 비대칭 계수, 단산란 알베도 값을 정량화 하였다. 이러한 화산재입자의 고유 광학 특성값은 복사전달모델의 입력자료로 이용하여 다양한 에어러솔 광학두께(${\tau}$) 및 기하조건에서 원격탐사 센서(인공위성과 지상관측용)가 측정하는 이론적인 복사량과 화산재입자 특성의 관계를 분석하였다. 복사전달모델 분석결과, 대기권 최상층부에서 ${\tau}$ 에 대한 복사량의 변화율의 평균값은 안산암의 경우 부석보다 6배 정도 크게 나타났다. 지표에서 이러한 변화율은 ${\tau}$ <1인 경우 양의 상관관계를 보이지만, ${\tau}$ >1인 경우에는 음의 상관관계를 보였다. 그러나, 적외선 영역인 11 ${\mu}m$ 에서는 차이가 매우 적게 나타났으며, 여기서 발생하는 복사량의 오차범위는 광학두께가 증가할수록 커지는 양상을 보이며, 다항 회귀함수로 표현될 수 있다. 이러한 결과는 원격 탐사 관측자료를 이용한 화산재 관측에 있어서 화산재의 정량적 분석에 도움이 될 것이다.