Session D1.3. : 정보통신 : 네트워크 응용 프로그램 개발을 위한 JAVA 기반의 프레임워크 개발

심호준,김명호 ( Ho Jun Sim,Myung Ho Kim ) 한국정보시스템학회 1998 춘계공동학술대회 Vol.- No.-

Wake Characteristics of Vane-Type Vortex Generators in a Flat Plate Laminar Boundary Layer

심호준,조영희,장경식,성기정,박승오 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.3

Experimental and numerical investigations were conducted to identify the wake characteristics downstream of two vanetype vortex generators over laminar flat plate boundary layer. Experimental study was carried out by using the stereoscopic particle image velocimetry. To describe the flow field around the vortex generator in detail, numerical study was performed. We considered two different planform shapes of vortex generator: triangular and rectangular shape. The height of the generator was chosen to be about the boundary layer thickness at the position of its installation. Two different lengths of the generator were chosen: two and five times the height. Wake measurements were carried out at three angles of attack for each configuration. Wake characteristics for each case such as overall vortical structure, vorticity distribution, and location of vortex center with downstream distance were obtained from the PIV data. Wake characteristics, as expected, were found to vary strongly with the geometry and angle of attack so that no general tendency could be deduced. Causes of this irregular tendency were explained by using the results of the numerical simulation.

상용 프로펠러 공력 데이터베이스 구축을 위한 실험적 연구

심호준,김건홍,천혜진 항공우주시스템공학회 2021 항공우주시스템공학회지 Vol.15 No.5

Propeller performance measurement system for commercial propeller was designed and applied to the wind tunnel test for 3 commercial propeller models with diameters of 30 inch. The thrust and torque of the propeller was directly measured by using 6-components balance installed on the rotating axis. The measurement system was validated by using wind tunnel balance calibration equipment. Propeller test stand including measurement and rotating system was validated by using QTP propeller. In the hovering condition, we compared the performance test results and the specifications of the commercial propeller provided by the manufacturer and confirmed that there are differences in the thrust and the torque. We measured the propeller performance with various wind speeds, propeller models and angles of attack and was summarized by thrust coefficients. We confirmed that the trend of the thrust coefficients was different in the low angle of attack and high angle of attack. An aerodynamics database that can be used for future aerodynamic design of an unmanned aerial vehicle was secured. 상용 프로펠러의 추력과 토크를 측정하기 위한 성능시험 장치를 고안하였으며, 30인치급 3가지 프로펠러에 대한 성능시험을 수행하였다. 프로펠러 추력과 토크 측정을 위해 모터, 프로펠러와 연결된 6분력 발란스를 적용하였으며, 풍동 저울 교정 장비를 이용하여 측정 시스템의 확인을 수행하였으며, QTP 프로펠러를 적용하여 구축한 성능시험 장치의 검증 시험도 수행하였다. 제자리 비행 조건에서 상용 프로펠러의 제작사에서 제공하는 사양과 시험 결과를 비교하였으며, 추력 및 토크에서 차이가 있음을 확인하였다. 받음각, 프로펠러 형상, 풍속을 변경시켜가며 프로펠러 성능을 측정하였으며, 각 프로펠러에 대해 RPM에 따른 프로펠러 추력 계수로 나타내었다. 저 받음각과 고 받음각에서 경향이 다르게 나타남을 확인하였으며, 차후 공중용 무인이동체 공력 설계에 활용 가능한 공력 데이터베이스를 확보하였다.

MPEG-21 디지털 아이템 적응을 이용한 휴대용 멀티미디어 시스템의 전력 소모 절감 기법

심호준,조영진,김재민,장래혁,Shim Hojun,Cho Youngjin,Kim Jaemin,Chang Naehyuck 대한전자공학회 2006 電子工學會論文誌-SD (Semiconductor and devices) Vol.43 No.2

MPEG-21 멀티미디어 프레임워크는 다양한 종류의 네트워크와 장치들이 멀티미디어 자원을 보다 효율적으로 전달하고 사용할 수 있도록 지원하는 것을 목표로 하고 있다. MPEG-21의 주요한 목표 중 하나는 서로 다른 기종의 단말기기에서 동일한 가독성을 보여주는 멀티미디어 스트리밍(streaming)을 지원하기 위해서 디지털 아이템 적응(digital item adaptation, DIA)을 통한 광범위한 멀티미디어 접근성, 다시 말해서 UMA (universal multimedia access)를 구현하는 것이다. 본 논문에서는 MPEG-21 디지털 아이템 적응을 이용하여 단말기기의 전력 소모를 절감할 수 있는 방법을 최초로 소개한다. MPEG-21 멀티미디어 프레임워크는 처음부터 단말기기의 전력 소모 절감을 목적으로 설계된 것이 아니기 때문에, 단말기기.의 전력 소모에 관련된 상세한 정보를 제공할 수는 없지만 몇 가지 제한된 정보는 현 시점에서도 이용가능하다. 따라서 본 논문에서는 이러한 정보를 이용하여 MPEG-21 디지털 아이템 적응 표준을 따르는 여러 가지 전력 소모 절감 기법들을 제시하고, 각각의 전력 소모 절감 기법들 사이의 상호 의존 관계를 밝히고자 한다. 본 논문에서 소개한 전력 소모 절감 기법들을 단말기기에 적용하면 멀티미디어 서비스의 품질을 거의 손상시키지 않으면서 휴대용 멀티미디어 기기의 소비 전력을 최대 $66\%$까지 줄일 수 있다. The MPEG-21 Multimedia Framework initiative aims to support a wide range of networks and devices in the delivery and consumption of multimedia resources. One of the primary goals of MPEG-21 is universal multimedia access (UMA) through Digital Item Adaptation (DIA), which supports multimedia streaming to heterogeneous devices ensurung the same readability and seamlessness. We pioneer power saving of luminal devices with MPEG-21 DIA, so that the MPEG-21 DIA can also be used to support power saving, even though the framework is not primarily designed for power reduction and only limited power awareness is defined by DIA. We introduce several power-saving techniques conforming to MPEG-21 DIA specifications and show the dependency relation among introduced techniques. We achieve energy savings of up to $66\%$ in hand-held multimedia devices with minor QoS (quality of service) degradation.

Passive control of pitch-break of a BWB UCAV model using vortex generator

심호준,박승오 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3

To examine the effect of vortex generator on pitch-break control for a BWB model having lambda wing configuration, wind tunnelexperiments were conducted. Tests were carried out at two freestream velocities of 30 m/s and 60 m/s. Experimental results of the BWBmodel, which was modified slightly from UCAV 1303, at various angles of attack are presented. Aerodynamic force and moment coefficientsand chordwise pressure distributions at several spanwise stations are included. Spanwise location of a vortex generator was selectedbased on pressure distributions of the BWB model at several angles of attack and through a preliminary test. Well known pitchbreakor pitch-up phenomenon was identified to occur at a specific angle of attack for the case without vortex generator. When the vortexgenerator was installed, this pitch-break was found to be delayed to a much larger angle of attack, which might well be adopted for efficientflight control.

입자영상유속계를 이용한 대형수송함(LPH) 갑판 상부의 유동장 측정 연구

심호준,정진덕,조태환,이승훈,송지수,Shim, Hojoon,Chung, Jindeog,Cho, Taehwan,Lee, Seunghoon,Song, Gisu 대한조선학회 2022 大韓造船學會 論文集 Vol.59 No.4

The flow field measurement above whole area of the flight deck on 'Landing Platform Helicopter (LPH)' was performed by using PIV system in wind tunnel. In various heading angle conditions (0deg, -30deg, -45deg, -60deg, -75deg and ±90deg), the velocity fields such as U velocity & V velocity were measured at three different height above flight deck. Due to the geometrical characteristics of several bodies like deck, crane and super-structure, various vortex were generated. When the heading angle is 0deg, the deck edge vortex by flight deck and massive separation by super-structure were clearly observed by visualization with smoke and PIV, respectively. In other heading angles, the acceleration of flow in space between crane and super-structure were detected. And area with flow separation by super-structure is directly related to the heading angle of vessel.

Feasibility and safety of nasal route for linear EBUS: a single center experiences

심호준,하직환,김주상,김형우,신아영,안중현 대한내과학회 2018 대한내과학회 추계학술대회 Vol.2018 No.1

풍력발전 블레이드의 공력해석과 풍동실험기법

심호준,강경민,이동환 한국풍공학회 2007 한국풍공학회지 Vol.11 No.1

본 연구에서는 풍력발전에 적용되는 이론 분석을 통해 공력해석 프로그램을 개발하였으며, 풍동실험 결과와 비교 분석을 통해 정확성을 검증하였다. 그 결과로 개발한 계산 프로그램의 정확성과 유용성이 입증되어, 앞으로 새로운 풍차 익형 개발에 활용하고자 한다. In this study, we developed a new numerical program for the calculation of aerodynamic loads of wind turbine blade. The results of this numerical test is compared to the windtunnel test by a prony brake technique[5]. As these results, we get to prove the accuracy and utility of new program. From now, this program will make the use of development in efficient wind turbine blade.

풍력발전 블레이드의 공력해석과 풍동 실험 기법

심호준,이동환 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

무미익 BWB UCAV의 공력계수에 대한 실험적 연구

심호준,박승오,오세윤 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4

꼬리날개가 없는 BWB 형태의 무인전투기에 대한 기본 공력 실험을 수행하였으며, 본 연구는 국방과학연구소의 중형 아음속 풍동에서 수행되었다. 실험 형상은 UCAV 1303 기반의 lambda wing configuration이다. 실험 데이터는 6분력 내장 저울을 통해 획득하였으며, 레이놀즈 수 효과의 데이터 또한 확인하였다. 실험 풍속은 20 m/s에서 70 m/s까지 10 m/s 간격으로 수행되었으며, 받음각 범위는 -3°~25°이다. 풍속 증가에 따른 양력 계수, 항력 계수 그리고 피칭 모멘트 계수의 변화를 확인하였으며, 풍속 증가에 따라 최대 양력 계수의 증가와 항력 계수의 감소를 확인하였다. 또한 특정 받음각에서 피칭 모멘트가 급격하게 변화하는 pitch-up (or pitch break)현상을 확인하였다. The basic aerodynamic experiment about the tailless BWB UCAV configuration was conducted. This study was carried out at the low speed wind tunnel of the Agency for Defense Development(ADD-LSWT). The test model base is the lambda wing configuration of the UCAV 1303. The test data were acquired with the 6 component internal balance. The data of the Reynolds number effect were also identified. The range of the test wind speed is 20 m/s ~ 70 m/s and the tests were conducted with internals of 10 m/s. And the range of the angle of attack is -3°~25°. According to the wind speed increase, the changes of the lift coefficient, drag coefficient and pitching moment coefficient were identified in this study. And maximum lift coefficient was increased by the Reynolds number increase, drag coefficient was decreased by the Reynolds number increase. The pitch-up (or pitch break) phenomenon was also identified at the specific angle of attack.