• 방송공학회논문지
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• 제23권3호
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• pp.361-368
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• 2018

자율주행 자동차의 연구가 빠르게 발전하는 가운데 보행자 검출에 대한 연구 또한 성공적으로 진행되고 있다. 그러나 대부분의 연구에서 사용되는 데이터셋이 컬러영상을 기반하고 있고 또한 보행자의 인식이 상대적으로 쉬운 영상이 많다. 컬러 영상의 경우 보행자가 빛에 노출되는 정도에 따라 영상에 제대로 포착이 되지 않을 수 있고 이로 인해 기존 방식들로는 이러한 보행자를 제대로 검출하지 못하는 상황이 발생한다. 따라서 본 논문에서는 DNN (deep neural network) 기반 컬러 영상과 열 영상을 이용한 다중 스펙트럼 보행자 검출 기법을 제안하고자 한다. 기존의 SSD (single shot multibox detector) 기법을 기반으로 하여 컬러 영상과 열 영상을 동시에 활용하는 퓨전 네트워크 구조를 제안한다. 실험은 KAIST의 데이터셋을 이용하여 실시하였고 제안한 기법인 SSD-H (SSD-Halfway fusion)의 방식이 KAIST 보행자 검출기준의 기준치보다 18.18% 낮은 miss rate를 획득하였고 또한 기존 halfway fusion 기법에 비해 최소 2.1% 낮은 miss rate를 획득하였다.

• 대한기계학회논문집B
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• 제39권10호
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• pp.795-803
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• 2015

본 연구에서는 발전용 터빈 제 1 단 동익 흡입면에서 발달하는 경계층유동에 대하여 체계적으로 연구하였다. 이를 위해 흡입면에서 열부하가 급격하게 변화하는 대표적인 영역에 대하여, 경계층의 평균 유속, 난류강도, 에너지스펙트럼 등을 측정하였다. 그 결과 흡입면 경계층유동이 층류에서 난류 경계층으로 천이됨을 확인할 수 있었고, 이 천이경로는 박리버블의 전단층에서 주로 발생하는 박리유동 천이로 확인되었다. 흡입면에서 열부하의 최소값이 존재하는 곳은 흡입면 경계층유동의 천이가 시작되는 위치에 해당하며, 열부하가 최대인 곳은 박리유동 천이가 모두 마무리되어 벽근처에 강력한 난류유동이 존재하는 곳과 일치하였다. 에너지스펙트럼의 측정을 통하여, 흡입면 경계층의 박리유동 천이 전후에 나타나는 난류운동에너지의 주파수 특성을 자세히 파악할 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.435-440
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• 2006

In order to understand changes of water temperature for thermal discharge of Hadong power plant in Gwangyang and Jinju Bay, it was analyzed for temperature data of representative season by MEM(Maximum entropy method) that is one of the spectral analysises. And due to understand effect of thermal discharge at each point, analyzed spectral data showed reactive energy rate of reference point by calculating energy from 24 time period to height frequency zone. As a result of spectral analysis, it showed that there were 9 points which are largely effected, 7 points which will be estimated, 6 points which is difficult to estimate, 14 points which rarely effected by thermal discharge.

• Nuclear Engineering and Technology
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• 제43권3호
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• pp.217-242
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• 2011

A variety of Generation III/III+ water-cooled reactor designs featuring enhanced safety and improved economics are being proposed by nuclear power industries around the world in efforts to solve the future energy supply shortfall. Thermal-hydraulics is recognized as a key scientific subject in the development of innovative reactor systems. Phase change by boiling and condensation in the reverse process is a highly efficient heat transport mechanism that accommodates large heat fluxes with relatively small driving temperature differences. This mode of heat transfer is encountered in a wide spectrum of nuclear systems,and thus it is necessary to determine the thermal limit of water-cooled nuclear energy conversion in terms of economic and safety. Such applications are being advanced with the introduction of new technologies such as nanotechnology. Here, we investigated newly-introduced nanotechnologies relevant to boiling and condensation in general engineering applications. We also evaluated the potential linkage between such new advancements and nuclear applications in terms of advanced nuclear thermal-hydraulics.

• Journal of the Optical Society of Korea
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• 제20권3호
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• pp.396-400
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• 2016

Laser speckle patterns were used to monitor variations of thermal voltages of a cathode during a battery discharge. Discharge voltages measured with an oscilloscope were utilized as a figure of merit of thermal voltages in Zn metal. Using an optical imaging system, speckle patterns were taken for zinc metal surface over a time period of 3 minutes. Pixel sum distribution functions (PSDFs) were extracted from speckle patterns. Accumulated pixel sums quantified from PSDFs over an optimized grayscale range strongly correlated with discharge voltages. This suggested that dark matter or particles may have the capability of both absorbing and radiating thermal energies simultaneously. The black body-like properties were able to be validated by identifying coincidences with distinct features of a black body spectrum. The pixels belonging to the grayscale range were confirmed to represent dark matter of a speckle pattern. It was clear that dark matter was part of surface plasmon carriers. The proposed sensing system can be applied to monitor thermal energy variations in any material.

• 한국재료학회지
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• 제33권12호
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• pp.503-510
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• 2023

This comprehensive study delves into the intricate process of exfoliating and functionalizing boron nitride nanosheets (BNNSs) extracted from hexagonal boron nitride (h-BN), and meticulously explores their potential application within epoxy composites. The extensive research methodology encompasses a sequence of treatments involving hydrothermal and sonication processes aimed at augmenting the dispersion of BNNSs in solvents. Leveraging advanced analytical techniques such as Raman spectroscopy, X-ray diffraction, and FTIR spectroscopy, the study rigorously analyzes a spectrum of changes in the BNNS's properties, including layer count variations, interlayer interactions, crystal structure modifications, and the introduction of functional groups. The research also rigorously evaluates the impact of integrating BNNSs, specifically glycidyl methacrylate (GMA)-functionalized BNNSs, on the thermal conductivity of epoxy composites. The conclusive findings exhibit notable enhancements in thermal properties, predominantly attributed to the enhanced dispersion of fillers and enhanced interactions within the epoxy matrix. This pioneering work illuminates the wide potential of functionalized BNNSs for significantly enhancing the thermal conductivity of epoxy composites, paving the way for advanced materials engineering and practical applications.

• 한국산학기술학회논문지
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• 제1권2호
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• pp.27-31
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• 2000

대상 물체의 온도분포를 해석하고 계측하기 위해 열상 장비가 구현된다. 시스템의 주요한 부분은 초점면 배열 형태의 센서가 적용된 열상 카메라이다. 적용된 열상 센서는 중파장 적외선 영역의 신호를 검출하며 열상을 형성하기 위한 기본 신호를 출력한다. DSP가 활용되어 센서 신호처리를 통해 열상을 구성하고 NTSC 신호 및 디지털 신호 출력을 한다. 열상의 화질을 개선하기 위해 이점 교정법을 적용한다. 이는 낮은 온도와 높은 온도를 기준으로 하여 초점면 배열 센서 화소 신호의 공간적인 비균일함을 교정하는 것으로서 실험 결과를 통해 열상의 화질이 개선됨을 보인다.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.587-590
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• 2011

The absence of deep traps for electrons in the spectrum of $As_{40}Se_{30}S_30$ localized states films obtained by ion sputtering was determined. Bipolar drift of charge carriers was found in amorphous $As_{40}Se_{30}S_30$ films of chalcogenide glassy semiconductors, obtained by ion-plasma sputtering of high-frequency, unlike the films of these materials obtained by thermal evaporation.

• 대한지리학회:학술대회논문집
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• 대한지리학회 2004년도 춘계학술대회
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• pp.56-56
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• 2004

The ability to detect urban heat islands in satellite imagery is a function of spatial, spectral, and temporal resolutions. Imagery from the satellite-mounted Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor acquired since December 1999 allows us to view the Earth at a higher spectral resolution in the thermal infrared (TIR) portion of the electromagnetic spectrum than most other satellite systems (e.g., AVHRR, Landsat TM). (omitted)

• 한국자기공명학회논문지
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• 제22권2호
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• pp.40-45
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• 2018

We report Optically-Detected Magnetic Resonance (ODMR) study on Nitrogen-Vacancy (NV) centers in diamond. The experiment can easily be conducted with basic optics and microwave components. A diamond crystal having a high-density NV center is suitable for the ODMR study. The magnetic field dependence of ODMR spectrum allowed us to determine the orientation of the diamond crystal. In addition, we measured the variation of the ODMR spectrum as a function of the excitation laser power. Thermal heating induced by optical absorption caused the monotonic decrease of zero field splitting. The contrast of the ODMR peak, however, increased and, then, began to decrease, indicating the optimal laser power for recording the ODMR spectrum.