• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.64-67
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• 1997

In the total artificial heart(TAH), a transcutaneous information transmission system(TITS) is vely important to monitor the TAH status and detect the device failure, and repair the possible problems. First of all, the communication channel(skin) and method were simulated in terms of transmittance, scattering, reflection and absorption, then the system was designed with size reduction including low power consumption and reliability compared to the previous one. The informations are transmitted through the skin(approximately 1cm in depth) by frequency modulated near infrared(NIR) pulses using 780nm laser diodes as transmitters and photodiode as receiver with high speed and high spectral sensitivity. The logic high and low frequencies are 3MHz, 1MHz respectively. The system is a bidirectional data link for more than 38.4Kbps data rate, full-duplex with a bit error rate of less than $10^{-5}$.

• 항공우주기술
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• 제2권1호
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• pp.182-189
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• 2003

국내 최초로 통신, 해양, 기상 3분야 복합 임무를 수행하는 정지궤도 위성인 통신해양기상위성이 2003년부터 개발되어 2008년 발사 예정이다. 본 연구에서는 통신해양기상위성의 기상관측 탑재체인 기상 영상기(Imager)의 개발을 위해 정지궤도 위성 기상 영상기의 Modulation Transfer Function (MTF) 특성을 연구하고 현재 운영 또는 개발 중인 정지궤도 기상 영상기 기술을 고려하여 기상 영상기의 분광 채널별 MTF 한계값을 분석하였다. 10㎛ 이상의 장파장 적외선에서 회절 현상으로 인해 현저히 낮은 MTF가 얻어질 수 있으므로 기상 영상기의 개발시 장파장 적외선 채널의 MTF 성능에 대한 주의가 요구된다.

• 천문학회보
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• 제37권1호
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• pp.61.1-61.1
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• 2012

We examine both optical and optical/near-infrared (NIR) color distributions of the globular cluster (GC) system in the core of the Coma cluster of galaxies (Abell 1656), centered on the giant elliptical galaxy NGC 4874, to study how non-linearities in the color-metallicity relations of GC systems in large elliptical galaxies are linked to bimodal optical color distributions. Since optical-NIR color distributions of extragalactic GC systems reflect the underlying features of the metallicity distributions, we also present the color-color relation for this GC system. In order to do this, we combine F160W ($H_{160}$) NIR imaging data acquired with the Wide Field Camera 3 IR Channel (WFC3/IR), newly installed on Hubble Space Telescope (HST), with F475W ($g_{475}$) and FF814W ($I_{814}$) optical imaging data from the HST Advanced Camera for Surveys (ACS). To quantitatively explain the feature of color distributions, we use the Gaussian Mixture Modeling (GMM) code. Finally, we show the radial distribution of the GCs in the field of NGC 4874.

• Design & Manufacturing
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• 제1권1호
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• pp.27-32
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• 2007

In the optical application demand for high quality lens is increasing. Plastics lenses are demanded more than glass lenses for large size lenses as well as micro-size lenses. It is difficult to apply typical straight cooling channels of injection mold to lens molding due to its non-uniform temperature distribution. In this study, we manufactured molds for plastic lenses with the conventional cooling channels and conformal cooling channels produced by the DMLS process. We evaluated cooling performance for the 2 molds by injection molding experiment. Also, uniformity of the temperature distribution was tested by infrared camera and temperature monitoring. We confirmed that the cooling performance and temperature uniformity with the conformal cooling channels is much improved from the ones with the conventional. The cooling time with the conformal cooling channels was reduced 30% compared with the conventional cooling channels.

• 대한원격탐사학회지
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• 제15권3호
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• pp.239-251
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• 1999

The elimination process of cloud-contaminated pixels is one of important steps before obtaining the accurate parameters of land and ocean surface from AVHRR imagery. We developed a 6step threshold method to detect the cloud-contaminated pixels from NOAA-14/AVHRR datime imagery over land using different combination of channels. This algorithm has two phases : the first is to make a cloud-free characteristic data of land surface using compositing techniques from channel 1 and 5 imagery and a dynamic threshold of brightness temperature, and the second is to identify the each pixel as a cloud-free or cloudy one through 4-step threshold tests. The merits of this method are its simplicity in input data and automation in determining threshold values. The threshold of infrared data is calculated through the combination of brightness temperature of land surface obtained from AVHRR imagery, spatial variance of them and temporal variance of observed land surface temperature. The method detected the could-comtaminated pixels successfully embedded inthe NOAA-14/AVHRR daytime imagery for the August 1 to November 30, 1996 and March 1 to July 30, 1997. This method was evaluated through the comparison with ground-based cloud observations and with the enhanced visible and infrared imagery.

• 로봇학회논문지
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• 제18권3호
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• pp.293-298
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• 2023

The military is facing a continuous decrease in personnel, and in order to cope with potential accidents and challenges in operations, efforts are being made to reduce the direct involvement of personnel by utilizing the latest technologies. Recently, the use of various sensors related to Manned-Unmanned Teaming and artificial intelligence technologies has gained attention, emphasizing the need for flexible utilization methods. In this paper, we propose four dataset construction methods that can be used for effective training of robots that can be deployed in military operations, utilizing not only RGB image data but also data acquired from IR image sensors. Since there is no publicly available dataset that combines RGB and IR image data, we directly acquired the dataset within buildings. The input values were constructed by combining RGB and IR image sensor data, taking into account the field of view, resolution, and channel values of both sensors. We compared the proposed method with conventional RGB image data classification training using the same learning model. By employing the proposed image data fusion method, we observed improved stability in training loss and approximately 3% higher accuracy.

• 천문학논총
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• 제21권2호
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• pp.67-74
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• 2006

We have developed a control electronics system for an infrared detector array of KASINICS (KASI Near Infrared Camera System), which is a new ground-based instrument of the Korea Astronomy and Space science Institute (KASI). Equipped with a $512{\times}512$ InSb array (ALADDIN III Quadrant, manufactured by Raytheon) sensitive from 1 to $5{\mu}m$, KASINICS will be used at J, H, Ks, and L-bands. The controller consists of DSP(Digital Signal Processor), Bias, Clock, and Video boards which are installed on a single VME-bus backplane. TMS320C6713DSP, FPGA(Field Programmable Gate Array), and 384-MB SDRAM(Synchronous Dynamic Random Access Memory) are included in the DSP board. DSP board manages entire electronics system, generates digital clock patterns and communicates with a PC using USB 2.0 interface. The clock patterns are downloaded from a PC and stored on the FPGA. UART is used for the communication with peripherals. Video board has 4 channel ADC which converts video signal into 16-bit digital numbers. Two video boards are installed on the controller for ALADDIN array. The Bias board provides 16 dc bias voltages and the Clock board has 15 clock channels. We have also coded a DSP firmware and a test version of control software in C-language. The controller is flexible enough to operate a wide range of IR array and CCD. Operational tests of the controller have been successfully finished using a test ROIC (Read-Out Integrated Circuit).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.864-867
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• 2006

Thermal infrared images of Landsat-5 TM and Landsat-7 ETM+ sensors have been unrivalled sources of high resolution thermal remote sensing (60m for ETM+, 120m for TM) for more than two decades. Atmospheric effect that degrades the accuracy of Sea Surface Temperature (SST) measurement significantly, however, can not be corrected as the sensors have only one thermal channel. Recently, MODIS sensor onboard Terra satellite is equipped with dual-thermal channels (31 and 32) of which the difference of at-satellite brightness temperature can provide atmospheric correction with 1km resolution. In this study we corrected the atmospheric effect of Landsat SST by using MODIS data obtained almost simultaneously. As a case study, we produced the Landsat SST near the eastern and western coast of Korea. Then we have obtained Terra/MODIS image of the same area taken approximately 30 minutes later. Atmospheric correction term was calculated by the difference between the MODIS SST (Level 2) and the SST calculated from a single channel (31 of Level 1B). This term with 1km resolution was used for Landsat SST atmospheric correction. Comparison of in situ SST measurements and the corrected Landsat SSTs has shown a significant improvement in $R^2$ from 0.6229 to 0.7779. It is shown that the combination of the high resolution Landsat SST and the Terra/MODIS atmospheric correction can be a routine data production scheme for the thermal remote sensing of ocean.

• 설비공학논문집
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• 제7권1호
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• pp.73-80
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• 1995

The object of the present study is to develop a high performance evaporator for automotive air conditioner. The experiment has been conducted on evaporative heat transfer coefficient inside a plate type heat exchanger with a sharp 180-degree turn flow. The test plates have different formed surface, cross-ribbed channel and elliptical-ribbed channel. Also experimental study has been performed to determine optimal design in elliptical-ribbed plate heat exchanger with different turn clearance. In addition to the above experiments, refrigerant behavior and surface temperature distribution in the plate heat exchanger were observed using color thermoviewer(infrared thermometer). In this experiment, working fluid was used R-12 and test conditions were as follows : (1) saturation pressure of $2.116kg/cm^2$, (2) mass fluxes of 40 to $70kg/m^2s$, (3) heat fluxes of 4,500 to $7,300W/m^2$, (4) inlet quality of 0.1 to 0.7. The results indicated that the evaporative heat transfer coefficient of an elliptical-ribbed plate heat exchanger was higher than that of cross-ribbed plate heat exchanger. Also optimal turn clearance in an elliptical-ribbed plate heat exchanger was determined.

• 한국광학회지
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• 제3권3호
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• pp.198-202
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• 1992

은 이온 교환법으로 만든 유리 도파로는 표면 굴절율 차가 크고 도파로 깊이가 얕기 때문에 반도체 박막 이식법을 이용한 반도체 소자와 유리 도파로의 혼성 집적에 사용되기에 적합하다. 이 노문은 묽게한 잘산화은 용액에서 이온 교환으로 만들어진 평면 및 채널 유리 도파로의 가시광선 및 적외선 파장영역에서의 특성을 보고한다. 특히 광통신에 중요한 파장인 1.5.$\mu$m에서의 단일 모우드 채널 도파로의 제작 조건을 결정하였다. 또한 여러가지 다른 구성 형태의 방향성 결합기가 제작되어 파장과 편광 방향에 따른 3dB 결합 길이가 결정되었다.