• 한국자동차공학회논문집
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• 제16권1호
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• pp.152-157
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• 2008

The biodiesel becomes one of the favorite alternative fuel applied to diesel engines. This research aims to understand the physics of spray and combustion characteristics of a biodiesel fuel in a constant volume chamber. For spray visualization, biodiesel was injected into a combustion chamber and a high speed camera was applied at various combustion conditions. To investigate heat-release rates and flame propagations, spark was ignited on a hydrogen fuel for the premixed combustion and then biodiesel was injected directly. In addition, parametric study was made by various geometries of combustion chambers and temperatures of fuels and injection pressures. This technology may contribute to improve the performance of bio-diesel engine and reduce emissions in future.

• 한국분무공학회지
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• 제15권3호
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• pp.150-156
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• 2010

Ethanol has properties of a lower setting point, higher oxygen contents, lower cetane numbers, and also higher volatility compared to biodiesel. Thus, biodiesel fuel can be improved in the fluidity of blending fuel and exhaust emissions by blended ethanol fuel. This research aims to understand combustion characteristics of biodiesel-ethanol blending fuel inside a constant volume chamber. High speed camera was applied to visualize the physics of development of combustion processes, and combustion pressure and exhaust emissions were measured at several blending ratios of ethanol and biodiesel fuel. This information may contribute to improve the performance of biodiesel engine and reduce emissions in future.

• 천문학회보
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• 제43권1호
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• pp.39.2-39.2
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• 2018

GW170817/GRB170817A establishes a double neutron star merger as the progenitor of a short gamma-ray burst, starting 1.7 s post-coalescence. GRB170817A represents prompt or continuous emission from a newly formed hyper-massive neutron star or black hole. We report on a deep search for broadband extended gravitational-wave emission in spectrograms up to 700 Hz of LIGO O2 data covering this event produced by butterfly filtering comprising a bank of templates of 0.5 s. A detailed discussion is given of signal-to-noise ratios in image analysis of spectrograms and confidence levels of candidate features. This new pipeline is realized by heterogeneous computing with modern graphics processor units (GPUs). (Based on van Putten, M.H.PM., 2017, PTEP, 093F01.)

• 천문학회보
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• 제43권1호
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• pp.39.1-39.1
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• 2018

Although it is agreed that the gamma-ray bursts (GRBs) invoke highly relativistic jets with bulk Lorentz factors of a few hundreds, the exact physical mechanism producing such powerful gamma-rays still remains debated. Three outstanding and important questions in the field concern (1) the composition of GRB jets (i.e., matter-dominated vs Poynting-flux-dominated), (2) the involved radiative process responsible for the observed gamma-rays (i.e., synchrotron mechanism vs photospheric radiation), and (3) the distance of the emitting region from the central engine where the prompt gamma-rays are released (i.e., ~10^12 cm vs 10^14 cm vs 10^16 cm). I will present recent important breakthroughs that we have made, which answer these three questions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1797-1798
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• 2008

환자의 환부를 최소한으로 절개하여 시술하는 최소 침습 수술 수술은 많은 장점을 가지고 있어 그 활용도가 점차 확대되고 있다. 하지만 조작하는 조직으로부터 눈과 손이 분리되어 있기 때문에 많은 문제점들이 발생한다. 그 중 하나는 수술 영역과 시각 영역이 분리되어 발생하는데, 최적의 위치조정을 위한 자동 복강경 수술 로봇 팔 시스템 도입으로 이러한 문제를 해결하고 있다. 본 연구에서는 복강경 수술 로봇 팔을 설계하는데 있어 동작 범위를 빠르게 시각화하여 설계 단계에서 다양한 파리미터를 적용하여 보다 효율적인 복강경 수술 로봇 팔의 설계 방법을 제시한다. 제안된 물리 엔진을 이용한 동작 범위 분석 방법은 역기구학을 계산할 필요가 없으며, 설계가 바뀌어도 추가로 산출해야 하는 수식 없이 바로 수정된 기구학만으로 동작 범위 분석이 가능하다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2008년도 한국컴퓨터종합학술대회논문집 Vol.35 No.1 (C)
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• pp.295-298
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• 2008

본 논문에서는 물리엔진 기반으로 지능형 주행 시스템을 구현하여 사용자에게 쾌적한 주행 환경을 제공하여 사용자가 즐거움을 느낄 수 있도록 하는 것에 목적을 두고 있다. 이를 위해 시스템 환경 내에서 사용자의 위치 및 회전각을 추출한 다음 유한 상태 머신과 베이즈 이론에 입각하여 구현된 모듈에 입력하여서 분석을 한다. 그리고 모듈에서 나온 분석 결과를 장애물이나 커브 구역에서 제공 함으로서 사용자가 현 위치에 따른 환경을 인지하여 좀 더 나은 주행을 할 수 있도록 하였다. 또한 시스템 내부적으로 분석된 자료가 주행 시스템에 피드백 과정을 통해 입력되어 자동적으로 환경에 적응하여 주행 시간을 단축하는 시스템을 설계 하였고, 일부 기능에 대한 구현을 완료하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.441-447
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• 2005

The present study is aimed at understanding the flow physics associated with a safety valve applied to LNG ship engines. One-dimensional gasdynamic analyses and axisymmetric, compressible Navier-Stokes computations have been carried out to provide a qualitative and quantitative knowledge base for an effective design of the safety valve. Gasdynamic forces and thrust coefficients are obtained regarding a change in chamber pressure and distance between the nozzle exit and valve sheet which are major parameters to offer a variation in the flow feature. The present results show that the control of the passage area between the nozzle exit and valve sheet can attenuate the strength of shockwave generated in front of the valve sheet, which causes harm to stable system operation.

• 한국자동차공학회논문집
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• 제17권3호
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• pp.1-7
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• 2009

Ethanol has properties of a lower setting point, higher oxygen contents, lower cetane numbers, and also higher volatility compared to biodiesel. Thus, biodiesel fuel can be improved in the fluidity of and exhaust emissions by blended ethanol fuel. This research aims to understand combustion characteristics of biodiesel-ethanol blending fuel inside a constant volume chamber by obtaining some fundamental data in order to improve combustion atmosphere. To understand the physics of combustion, high speed camera was applied to visualize the development of combustion processes, and combustion pressure and exhaust emission were measured at several blending ratios of ethanol and biodiesel fuel. This information may contribute to improve the performance of biodiesel engine and reduce emissions in future.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (2)
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• pp.718-720
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• 2003

국내 게임 분야의 기술은 업소용 게임장을 중심으로 3차원 영상과 부분적인 체감형 인터페이스를 채용한 게임이 빠른 증가 추세이고, 게임 내용에 따른 재미 요소와 인간의 감각을 매개로 하는 다양한 체감형 반응.조작 장치의 시험적 상용화가 증가되고 있다. 따라서 3D 영상 및 실세계를 정밀하게 실시간으로 시뮬레이션 할 수 있는 물리 엔진의 필요성이 대두되고 있다. 이에 본 논문에서는 PC를 기반으로 한 물리엔진에 대한 설계와 구현 결과에 대해서 서술한다.

• Current Optics and Photonics
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• 제5권1호
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• pp.32-39
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• 2021

We propose a three-dimensional (3D) streaming system based on a lamina display that can convey field information in real-time by creating floating 3D images that can satisfy the accommodation cue. The proposed system is mainly composed of three parts, namely: a 3D vision camera unit to obtain and provide RGB and depth data in real-time, a 3D image engine unit to realize the 3D volume with a fast response time by using the RGB and depth data, and an optical floating unit to bring the implemented 3D image out of the system and consequently increase the sense of presence. Furthermore, we devise the streaming method required for implementing augmented reality (AR) images by using a multilayered image, and the proposed method for implementing AR 3D video in real-time non-face-to-face communication has been experimentally verified.