VLC 시스템에서 IR을 통한 사용자 위치에 따른 채널 할당 기법

한두희,조주필,김균탁,이계산,이규진,Han, Doohee,Cho, Juphil,Kim, GyunTak,Lee, Kyesan,Lee, Kyujin 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.2

In this paper, we proposed Channel allocation scheme according to the user's location with IR. In VLC System, LED can generate various colors of light by controlling the mixing ratio of each individual RGB color element. Thus, each RGB channel will have a different signal power, and each channel will have different performance. This proposed system using Visible light(RGB) as way to transmit signals, it depends on the mixture RGB, which decided the color of light, moreover, each things determined their performance. However, if the signal were fixed allocated RGB to transmit such as the original system, the importance of the each signals a different occur the limit on the quality of signals. To solve this problem in this paper, according to the RGB mixture ratios analyze the performance for the LED, which analyzed based on allocating the signal by transmitting to improve the quality was about how researched. In addition, our proposed system is able to improve the performance of BER and satisfied the Qos to desire users.

어븀 첨가된 고리형 광섬유 레이저의 수동형 고차 조화 모드로킹 ( High Harmonic passive mode-locking of a ring-type Er-doped fiber laser )

한두희,김경헌,김호영,이학규 한국통신학회 1997 한국통신학회 기타 간행물 Vol.- No.-

냉동기유로써의 Ester Oil의 합성 및 마찰 , 마모 특성에 관한 연구

한두희,강석춘,김종호,조원오,박미선 한국트라이볼로지학회 1994 한국트라이볼로지학회 학술대회 Vol.19 No.-

밀폐용기 연소실험 시 센서위치에 따라 변화하는 압력 진동에 대한 수치적 연구

한두희,안길환,류병태,성홍계 한국추진공학회 2018 한국추진공학회지 Vol.22 No.2

A computational fluid dynamics simulation of pyrotechnic material combustion inside a cylindrical closed vessel was carried out using the Eulerian–Lagrangian method. The 5th order upwind WENO scheme and the improved delayed detached eddy turbulence model were implemented to capture shock waves. The flow structure was analyzed inside the cylindrical vessel with a pressure sensor installed at the side wall center. The analysis revealed that the pressure oscillated because of the shock wave vibration. Additionally, the simulation results with four different sensor tab depths implied that, inside the sensor tab, eddies were generated by the excessively large gap between the sensor diaphragm and the side wall. These eddies caused irregularity to the measured time-pressure curve, which is an undesirable characteristic. 밀폐용기 내 Zirconium/Potassium Perchlorate의 연소를 수치적 모델링을 통해 전산해석을 수행하였다. 5차 WENO 공간차분법과 improved delayed detached eddy (IDDES) 난류모델을 사용하여 충격파가 동반되는 내부 유동구조를 모사하였고, 라그랑지안 연소모델을 통해 화약 입자를 계산하였다. 옆면 중앙에 센서가 설치된 원통형 밀폐용기 내부 유동분석을 통해 압력 진동이 발생하는 원인을 규명하였다. 또한 센서 다이어프램 깊이 변화에 따라 측정되는 압력 데이터를 실험값과 비교분석 하였다. 그 결과 센서 탭의 깊이가 약 2.36 mm 이상으로 커지면 유동속도가 아음속으로 감쇠하고 복잡한 eddy가 발생하여 측정값에 큰 불규칙성을 야기하는 현상을 관측하였다.

군집 알루미늄 입자의 연소 모델링 및 수치해석

한두희,성홍계 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.4

본 연구는 고 에너지 물질인 알루미늄 입자 연소에 대한 수치적 모델링 및 검증을 수행하였다. 해석은 Eulerian-Lagrangian 이상 유동 해석 기법을 적용하였다. 연구 목적은 알루미늄 입자를 포함한 대용량 전산해석에 적용 가능한 입자연소를 모델링하고, 계산의 단순화를 위해 실험적으로 계산된 연소시간 상관관계식을 적용하였다. 단일 알루미늄입자 연소 모델은 자유낙하 입자 연소 실험결과와 비교 검증하고, 군집 알루미늄 입자의 연소 및 수치 모델은 알루미늄-공기 분젠버너 실험과 비교 검증하였다. 군집입자의 연소 모델링의 해석 결과는 실험의 화염구조(화염 부양 높이, 화염 높이, 화염 두께 등)와 비교하여 매우 유사한 결과를 제시하였다. Numerical analysis on dust combustion of cloud aluminum particles has been conducted using Eulerian-Lagrangian method. The purpose of this study is proposing the combustion modeling scheme applicable for real scale engine combustor including dust aluminum particles. Several experimental correlations causes the dust combustion model to be computed by current computation resources. Single particle combustion, freely falling in a furnace, has been validated with experimental and analytical data. The dust combustion has been validated with the experimental flame structure of aluminum-air Bunsen burner such as lift height, length, and thickness of flame speed.

Parametric Analysis and Design Optimization of a Pyrotechnically Actuated Device

한두희,성홍계,장승교,류병태 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.3

A parametric study based on an unsteady mathematical model of a pyrotechnically actuated device was performed for design optimization. The model simulates time histories for the chamber pressure, temperature, mass transfer and pin motion. It is validated through a comparison with experimentally measured pressure and pin displacement. Parametric analyses were conducted to observe the detailed effects of the design parameters using a validated performance analysis code. The detailed effects of the design variables on the performance were evaluated using the one-at-a-time (OAT) method, while the scatter plot method was used to evaluate relative sensitivity. Finally, the design optimization was conducted by employing a genetic algorithm (GA). Six major design parameters for the GA were chosen based on the results of the sensitivity analysis. A fitness function was suggested, which included the following targets: minimum explosive mass for the uniform ignition (small deviation), light casing weight, short operational time, allowable pyrotechnic shock force and finally the designated pin kinetic energy. The propellant mass and cross-sectional area were the first and the second most sensitive parameters, which significantly affected the pin’s kinetic energy. Even though the peak chamber pressure decreased, the pin kinetic energy maintained its designated value because the widened pin cross-sectional area induced enough force at low pressure.

무기계고화재의 슬러지 개량토 제조에 관한 융합연구

한두희 한국융합학회 2017 한국융합학회논문지 Vol.8 No.2

제지슬러지 소각재, 용광로 슬래그 미세분말 생석회, 무수석고 및 프라이애쉬 등을 혼합하여 무기계고화 재를 제조하였다. 슬러지 처리용으로 개발된 고화재의 주성분은 SiO, Al₂O3, TiO2, Fe₂O3, Mn₂O3, CaO, MgO, Na₂O, K₂O, P₂O, SO₃이었다. 시멘트와 달리, 개발된 고화재에는 발암물질로 알려진 Cr6+가 함유되지 않았다. 중금속 및 기름 오염토를 고화재와 혼합한 후 7일간 양생하여 빗물용출실험을 시행한 결과 중금속이 미미하였다. 하수슬러지 케이크 및 음식물쓰레기와 고화재를 각각 혼합하여 7일 양생 후 토양성분실험을 한 결과 중금속 함량이 환경기준치 이하로 나타났다. 슬러지, 고화재 및 첨가제 혼합시료를 비이커에 혼합한 후 암모니아 농도를 측정한 결과 3일 후 0이 되었다. Inorganic stiffening agents were prepared by mixing paper sludge incineration ash, blast furnace slag fine powder quicklime, anhydrous gypsum and fly ash. The main components of the solidifying agent developed for sludge treatment were SiO, Al2O3, TiO2, Fe2O3, Mn2O3, CaO, MgO, Na2O, K2O, P₂O, and SO3. Unlike cement, the developed solidifying agent did not contain Cr6+, which is known as a carcinogen. Heavy metals and oil contaminated soil were mixed with solidifying agent and cured for 7 days and the heavy metal content was below the environmental standard. Sewage sludge cake, food waste and solidifying agent were mixed with each other, and after 7 days curing, soil component test showed that the heavy metal content was below the environmental standard. After mixing the sludge, solidifying agent and additive mixture into the beaker, the ammonia concentration was measured to be 0 after 3 days.

Eulerian-Lagrangian 기반 군집 알루미늄 연소의 격자 의존성 연구

한두희,성홍계 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

본 연구는 고 에너지 물질인 군집 알루미늄 입자 연소에 대한 수치적 모델링 및 격자 의존도 계산을 수행 하였다. Eulerian-Lagrangian 기법을 사용하여 군집 입자의 연소현상을 모사하였다. 공기-알루미늄 혼합물이 채워져 있는 사각 관내에서 화염 전파속도를 계산하여 격자 의존성을 계산하였고, 입자보간법 및 공간 차분법에 따라 격자 수렴성이 영향을 받는 것을 확인 하였다. Numerical analysis on dust combustion of cloud aluminum particles has been conducted using Eulerian-Lagrangian method. The purpose of this study is suggesting the results of grid dependency tests. The dust combustion has been simulated using the combustion of pre-mixed aluminum-air mixture in a square duct. A grid dependency with a different order of space discretization and a particle interpolation was suggested. 4th order central discretization with a particle interpolation method showed a most reduced grid dependency in a Eulerian-Lagrangian aluminum flame propagation.

Numerical and experimental studies on the mixing characteristics of two jets with inclined angles in a rectangular chamber

한두희,신준수,강정석,박정신,박선상,곽재수,성홍계,최호진 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

Mixing characteristics in a rectangular chamber are investigated using experimental and numerical methods. A mixing chamber withan axial inlet (representing fuel inlet) and a side inlet (representing air inlet) is designed. Two jets with different momentum ratiosthrough the two inlets are mixed in the chamber. Computational fluid dynamic simulation is validated by experimental data of particleimage velocimetry that measures flow velocity distribution. The momentum ratios of the two jets and the height of the axial inlet significantlyinfluence the penetration depth of axial jet into the mixing chamber and the pressure drops at recirculation zones.

유기성 슬러지 처리 시스템에 관한 융합연구

한두희 한국융합학회 2020 한국융합학회논문지 Vol.11 No.10

천연 광물질, 식물질, 정수장 슬러지를 이용하여 친환경적인 수수질정화제와 이를 활용하는 오폐수복합처리시스 템을 개발하였다. 오폐수복합처리시스템은 오염수 유입, 수질정화제 투입, 가압부상장치 가동, 슬러지 부상, 슬러지 수거 및 처리수 배출의 과정을 거친다. 이 장치를 축분 탈리액, 육계 세척수, 공장 폐수, 하수종말처리장 및 연못의 녹조제거 에 적용하여 우수한 제거율을 얻었다. 유기성 폐기물 정화에 천연 수질정화제를 활용한 예는 조사되지 못했다. An eco-friendly water purifier was developed using natural minerals, plants, and sludge from water purification plants. A wastewater complex treatment system using this water purification agent was developed. The wastewater complex treatment system goes through the process of inflow of contaminated water, input of water purification agent, operation of a pressurized flotation device, sludge flotation, sludge collection and treatment water discharge. This device was applied to the removal of green algae in livestock desorption liquid, broiler washing water, factory wastewater, sewage treatment plant and pond to obtain excellent removal rate. The use of natural water purification agents for organic waste purification has not been investigated.