• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.135-139
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• 2005

Thin films of $BaTiO_3$ system were prepared by radio frequency(rf)/dc magnetron sputtering method. We have investigated crystal structure, surface morphology and PTCR(positive-temperature coefficient of resistance) characteristics of the specimen depending on second heat-treatment temperatures. Second heat treatments of the specimen were performed in the temperature range of 400 to $1350^{\circ}C$. X-ray diffraction patterns of $BaTiO_3$ thin films show that the specimen heat treated below $600^{\circ}C$ is an amorphous phase and the one heat treated above $1100^{\circ}C$ forms a poly-crystallization. In the specimen heat-treated at $1300^{\circ}C$, a lattice constant ratio (c/a) was 1.188. Scanning electron microscope(SEM) image of $BaTiO_3$ thin films of the specimen heat treated in between 900 and $1100^{\circ}C}$ shows a grain growth. At $1100^{\circ}C$, the specimen stops grain-growing and becomes a poly-crystallization.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.105-110
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• 2019

Most titanium alloy waste with cutting oil was discarded without recycling process so that it can be caused by metal and oil fires. However, there is no fire management system and studies on the titanium or titanium alloy waste in spite of high fire risk. The purpose of this experimental study is to identify the fire risk of the titanium alloy waste with cutting oil. We collected the 120g waste which was made in the biomedical titanium alloy cutting process. The waste was burned and conducted thermal image analysis with infrared camera. The experimental results which illustrated the process, characteristics, and trends of fire are presented. Firstly, the cutting oil was burned and partially the titanium alloy waste was burned. The maximum temperature of the fire was more than $650^{\circ}C$ in some specific spots. These results means when a lot of titanium alloy waste with cutting oil was ignited, this fire could connect the titanium fire. In other words, the fire has a flammable liquid fire and combustible metal fire at the same time. The experimental study could be used fire prevention, response, and investigation of the titanium alloy waste.

• Current Optics and Photonics
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• v.3 no.1
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• pp.8-15
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• 2019

We describe a common optical system that merges a LADAR system, which generates a point cloud, and a more traditional imaging system operating in the LWIR, which generates image data. The optimum diameter of the entrance pupil was determined by analysis of detection ranges of the LADAR sensor, and the result was applied to design a common optical system using LADAR sensors and LWIR sensors; the performance of these sensors was then evaluated. The minimum detectable signal of the $128{\times}128-pixel$ LADAR detector was calculated as 20.5 nW. The detection range of the LADAR optical system was calculated to be 1,000 m, and according to the results, the optimum diameter of the entrance pupil was determined to be 15.7 cm. The modulation transfer function (MTF) in relation to the diffraction limit of the designed common optical system was analyzed and, according to the results, the MTF of the LADAR optical system was 98.8% at the spatial frequency of 5 cycles per millimeter, while that of the LWIR optical system was 92.4% at the spatial frequency of 29 cycles per millimeter. The detection, recognition, and identification distances of the LWIR optical system were determined to be 5.12, 2.82, and 1.96 km, respectively.

• Journal of People, Plants, and Environment
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• v.22 no.3
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• pp.233-239
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• 2019

This study was conducted in order to predict the vase life of cut lily 'Woori Tower' flowers using a non-destructive thermal imaging technique. It was found that the temperature of cut lily flowers was maintained at 20℃ and was slightly lower than the air temperature until they bloomed. On the 11th day, when flowers bloomed, the temperature of leaves and flowers was measured to be 18.75±0.38℃ and 19.23±0.32℃ respectively, and their difference with ambient temperature was over 3℃. The flower temperature increased slightly when the vase life of cut lily flowers ended, and the temperature difference between the air and leaf temperature (1.77℃) and between the air and flower temperature (1.39℃) got smaller. No visible aging symptom was observed, but it was found that the temperature had risen due to water losses and less functional stomata. The vase life of cut lily flowers can be predicted based on changes in temperature and it will be also possible to predict the potential quality and vase life of cut flowers before harvesting them in greenhouses.

• Journal of Broadcast Engineering
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• v.26 no.2
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• pp.155-166
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• 2021

Most object detection algorithms are studied based on RGB images. Because the RGB cameras are capturing images based on light, however, the object detection performance is poor when the light condition is not good, e.g., at night or foggy days. On the other hand, high-quality infrared(IR) images regardless of weather condition and light can be acquired because IR images are captured by an IR sensor that makes images with heat information. In this paper, we performed the object detection algorithm based on the compression ratio in RGB and IR images to show the detection capabilities. We selected RGB and IR images that were taken at night from the Free FLIR Thermal dataset for the ADAS(Advanced Driver Assistance Systems) research. We used the pre-trained object detection network for RGB images and a fine-tuned network that is tuned based on night RGB and IR images. Experimental results show that higher object detection performance can be acquired using IR images than using RGB images in both networks.

• The Journal of Internal Korean Medicine
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• v.25 no.3
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• pp.559-568
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• 2004

Diagnosis of Raynaud's phenomenon is primarily based on clinical symptoms. Cold stress test(CST) done by DITI(Digital Infrared Thermographic Image) can be helpful for objective diagnosis. The cold stress test was performed three times by DITI; the first after 15 minutes of rest, the second right after one minute of soaking in $20^{\circ}C$ water, the third ten minutes after immersion. For a clear diagnosis, the temperature of the finger tips must be low, or the thermal difference between the metacarpophalangeal joints and the fingertips must be large. Also the evaluation of treatment depends on decrease of thermal gradient between the metacarpophalangeal joints and the finger tips after CST. In oriental medicine Raynaud's phenomenon can be categorized by coldness of the limbs or numbness. Numbness was diagnosed as depression of Ki and Chiljehyangbuhwan(Qizhixiangfuwan) was prescribed. Positive results were observed, not only in follow up CST, but also Visual Analogue Scale after treatment.

• Journal of the Korean Geotechnical Society
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• v.39 no.10
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• pp.41-48
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• 2023

The presence of abnormalities in the subgrade of roads poses safety risks to users and results in significant maintenance costs. In this study, we aimed to experimentally evaluate the temperature distributions in abnormal areas of subgrade materials using infrared cameras and analyze the data with machine learning techniques. The experimental site was configured as a cubic shape measuring 50 cm in width, length, and depth, with abnormal areas designated for water and air. Concrete blocks covered the upper part of the site to simulate the pavement layer. Temperature distribution was monitored over 23 h, from 4 PM to 3 PM the following day, resulting in image data and numerical temperature values extracted from the middle of the abnormal area. The temperature difference between the maximum and minimum values measured 34.8℃ for water, 34.2℃ for air, and 28.6℃ for the original subgrade. To classify conditions in the measured images, we employed the image analysis method of a convolutional neural network (CNN), utilizing ResNet-101 and SqueezeNet networks. The classification accuracies of ResNet-101 for water, air, and the original subgrade were 70%, 50%, and 80%, respectively. SqueezeNet achieved classification accuracies of 60% for water, 30% for air, and 70% for the original subgrade. This study highlights the effectiveness of CNN algorithms in analyzing subgrade properties and predicting subsurface conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.1033-1041
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• 2014

Rapid urbanization of Korea was an unprecedented example in the world and urban population increased significantly. As a result, unbalanced distribution of population is serious problem in Korea because approximately 50% of the population is concentrated in the capital area that is 10% of nation's territory, thereby occurring various urban problems including UHI. Hence, Sejong Special Autonomous City was inaugurated officially on 2 July 2012 in order to decentralize population of capital area and induce more balanced regional development. The Sejong City has been changed drastically over a period of years as developed practically since the late 2000's and is expected to have new problems of urbanization. The land cover change due to urbanization is the main cause of UHI that urban area is significantly warmer than its surrounding areas and UHI is not only affecting urban climate change but also natural environment. So the purpose of this research is to analyze level of urbanization and UHI effect and to provide the correlation analysis between Land Surface Temperature and spectral indices. To achieve this, satellite imagery from LANDSAT were used. NDVI, NDBI, and UI were calculated using red, near-infrared, mid-infrared ($0.63{\mu}m-1.75{\mu}m$) images and LST was retrieved utilizing thermal infrared ($10.4{\mu}m-12.5{\mu}m$) image. Based on each index and LST, Changes of NDVI, UI and UHI through TVI were analyzed in Sejong City. UHI effect increased around newly constructed multi-functional administrative city, the correlation between LST and NDVI was negative and UI was strong positive.

• Korean Journal of Optics and Photonics
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• v.29 no.3
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• pp.110-118
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• 2018

We have designed a mid-infrared optical system for an airborne electro-optical targeting system. The mid-IR optical system is a dual-field-of-view (FOV) optics for an airborne electro-optical targeting system. The optics consists of a beam-reducer, a zoom lens group, a relay lens group, a cold stop conjugation optics, and an IR detector. The IR detector is an f/5.3 cooled detector with a resolution of $1280{\times}1024$ square pixels, with a pixel size of $15{\times}15{\mu}m$. The optics provides two stepwise FOVs ($1.50^{\circ}{\times}1.20^{\circ}$ and $5.40^{\circ}{\times}4.23^{\circ}$) by the insertion of two lenses into the zoom lens group. The IR optical system was designed in such a way that the working f-number (f/5.3) of the cold stop internally provided by the IR detector is maintained over the entire FOV when changing the zoom. We performed two analyses to investigate thermal effects on the image quality: athermalization analysis and Narcissus analysis. Athermalization analysis investigated the image focus shift and residual high-order wavefront aberrations as the working temperature changes from $-55^{\circ}C$ to $50^{\circ}C$. We first identified the best compensator for the thermal focus drift, using the Zernike polynomial decomposition method. With the selected compensator, the optics was shown to maintain the on-axis MTF at the Nyquist frequency of the detector over 10%, throughout the temperature range. Narcissus analysis investigated the existence of the thermal ghost images of the cold detector formed by the optics itself, which is quantified by the Narcissus Induced Temperature Difference (NITD). The reported design was shown to have an NITD of less than $1.5^{\circ}C$.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.169-169
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• 2017

스마트 돈사 내의 열환경 분석에 필수적으로 고려되어야 인자는 가축의 복사 에너지 변화로 볼 수 있다. 열환경 제어의 대상이기도 하지만 회귀적으로 열환경 변화의 인자이기도 하다. 이러한 가축의 복사 에너지 분석을 위하여 시설 내에 용이하게 배포가 가능한 열화상 계측 시스템을 개발하였다. 초소형 마이크로 열화상 계측 시스템에 부가적으로 IOT(Internet of Thing) 기반 기술을 이용한 모듈화 개발을 병행하였다. 열화상 계측 센서로 LWIR(Longwave infrared)영역에 해당하는 $8{\mu}m{\sim}4{\mu}m$의 영역에서 $0.05^{\circ}C$의 분해능을 보이는 $Lepton^{TM}$ (500-0690-00, FLIR, Goleta, CA)모델을 사용하였다. SPI(Serial Peripheral Interface) 속도 2 Mhz로 마이크로프로세서(NanoPi NEO Air, FrendlyArm, CA, USA)와 고속 통신을 수행하여 9 Hz의 계측이 가능하다. 열화상 센서와 마이컴으로 구성되는 단위 계측 시스템의 통신 기능 확장을 위하여 다음과 같이 세 단계의 정보 전달 시나리오를 설계하였다. 1) 단독적으로 열화상을 계측 하고 내장된 메모리에 저장하는 형식 2) 인접한 사용자 인터페이스에서 1번 단독 모듈에 접속하여 열화상을 실시간으로 전송하여 화면에 도시하는 형식 3) 2번 사용자 도시모듈과 병행적으로 Local WI-FI 통신을 이용한 모바일 기기에 화면을 도시하는 형식. 이와 같은 계층적이며 모듈화된 계측 시스템을 구성하기 위해서 1번 모듈에 공개 소프트웨어인 Hostapd 2.5(http://w1.fi/hostapd)버전을 설치하였다. 외부 인터넷 환경이 없는 상황에 1번 모듈 단독으로 AP(Access Point) 기능을 제공하여 지근 거리에 있는 2번 모듈과 3번 모바일 기기의 접속을 관리할 수 있다. 2번 모듈의 경우 화면 다수의 1번 모듈에 접속을 교차적으로 수행하는 방식과 2번 모듈 자체가 AP가 되어 1번 모듈의 접속을 허용하는 형태로 구성되어 있다. 계측 시스템의 계측 매트릭스 구성에 따라 선택적으로 결정할 수 있다. 1번 2번 모듈 공통적으로 TCP/IP Listener와 Client 서비스를 병렬적으로 수행할 수 있도록 개발을 하였다. 3번 모바일 기기에서 사용자 인터페이스 구현을 위하여 범용 Android 기반 GUI 프로그램과 Socket 통신을 연동시켰다. 1개의 열화상 Frame의 전송량은 9,600 Byte ($=80{\times}60{\times}2Byte$) 로 WI-FI 통신 전송 시 2회 ~ 6회 정도 내외로 가변적인 통신 수행 횟수를 나타내었다. 센서 계측 시스템과 정보 전송 시스템을 병렬적으로 구성한 모듈화 된 계측시스템의 전 요소에서 센서에서 제공하는 최대 계측 주기인 9 Hz 구현이 일반적으로 가능하였다. 이를 이용한 추후 연구를 통해 가축 객체의 열복사 정보와 돈사 내 열환경 간의 역학성을 연구할 것이다.