적외선 파장대에서의 물체의 겉보기온도 예측

정진수,고상근,유호선,Jung, Jinsoo,Kauh, S. Ken,Yoo, Hoseon 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.3

Target detection by the infrared imager depends on the apparent temperature difference between the target and the background, so it is essential to predict apparent temperature variations for this purpose. In this study, thermal analysis program Including conduction, convection and radiation is developed and applied to a representative geometry adequate for examining the apparent temperature characteristics. The results show that the longwave emissivity in association with the background temperature affects the apparent temperature strongly but does not affect the physical temperature. It is revealed that the background temperature plays a role of tuning the apparent temperature. As the longwave emissivity decreases, the apparent temperature decreases when the target is hotter than the background, whereas it increases in the reversed situation. These findings imply that an effective surface treatment, such as painting of a less emissive material, may provide a less detection probability and contribute to preventing the target from being detected at night.

표적은폐도구의 유용도 평가를 위한 적외선화상 모사

정진수,고상근,유호선,Jung, Jinsoo,Kauh, S. Ken,Yoo, Hoseon 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.8

Camouflage measures in military purpose utilize the apparent temperature difference between target and background, so it is essential to develop a thermal analysis program for apparent temperature predictions and to apply some camouflage measures to real military targets for camouflage purpose. In this study, a thermal analysis program including conduction, convection and radiation is developed and the validity of radiation heat transfer terms is examined. The results show that longwave radiation along with solar radiation should be included in order to predict the apparent temperature as well as the physical temperature precisely. Longwave emissivity variation as an effective camouflage measures is applied to a real M2 tank. From the simulation results, it is found that an effective surface treatment, such as painting of a less emissive material or camouflage clothing, may provide a temperature similarity or a spatial similarity, resulting in an effective camouflage.

송출공의 회전이 송출계수와 압력계수에 미치는 영향

하경표,구남희,고상근,Ha, Kyoung-Pyo,Ku, Nam-Hee,Kauh, S.Ken 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.7

Pressure coefficient in rotating discharge hole was measured to gain insight into the influence of rotation to the discharge characteristics of rotating discharge hole. Pressure measurements were done by the telemetry system that had been developed by the authors. The telemetry system measures static pressure using piezoresistive pressure sensors. Pressure coefficients in rotating discharge hole were measured in longitudinal direction and circumferential direction with various rotating speed and 3 pressure ratios. From the results, the pressure coefficient, and therefore the discharge coefficient, is known to decrease with the increase of Ro number owing to the increase of flow approaching angle to the discharge hole inlet. However, there exists critical Ro number where the decrease rate of discharge coefficient with the increase of Ro number changes abruptly; flow separation occurs from the discharge hole exit at this critical Ro number. Critical Ro number increases with the increase of length-to-diameter ratio, but the increase is small where the length-to-diameter ratio is higher than 3. The decrease rate of discharge coefficient with the increase of Ro number depends on the pressure recovery at the discharge hole, and the rate is different from each length-to-diameter ratio; it has tendency that the short discharge hole shows higher decrease rate of discharge coefficient.

적분형 초음파 유량계를 이용한 SI엔진의 비정상 공연비 제어

장준석(J.S.CHang),김중일(J.I.Kim),고상근(S.Ken Kauh) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1

An accurate air flow rate measurement is essential to control the fuel injection rate of MPI engine. An integration type air flow meter(IFM), composed of an ultrasonic flow meter with an integration circuit, has significantly improved the accuracy of flow rate measurement compared with a hot wire type flow meter on certain conditions where a flow reversal exists, and the sampling method is also easier. On transient conditions, a conventional fuel injection control method has a limitation because it doesn't concern the dynamic characteristic of air and fuel system. The proposed control method estimates the air mass at the cylinder port using the air mass at the throttle, and also considers the fuel film dynamics. Consequently, the relative air-fuel ratio error includes 3% using the proposed control method.

하드웨어 구현을 기반으로 한 블루투스 스캐터넷 형성 알고리즘

이한욱(Han-Wook Lee),고상근(S. Ken Kauh) 한국정보과학회 2004 정보과학회논문지 : 정보통신 Vol.31 No.3

블루투스는 휴대폰을 비롯한 디지털 디바이스간의 탄력적이고 확장성 있는 무선 ad-hoc 네트워크를 제공할 수 있는 기술로 가능성을 인정받아왔다. 이러한 네트워크가 지원되기 위해서는 블루투스 스캐터넷(Scatternet)은 필수적인 요소이다. 그러므로 블루투스 스캐터넷과 관련되어서 현재까지 다양한 방법론이 제시되고 있다. 하지만 기존의 연구들은 시뮬레이션을 통한 방법론을 제시하는데 그치는 경우가 대부분이며, 스캐터넷의 탄력성과 확장성을 확보하지 못하고 그 복잡성으로 인해 하드웨어 구현에 제약이 있는 경우들이 많다. 본 논문에서는 실제 하드웨어 구현이 용이하고, 스캐터넷의 탄력성과 확장성을 확보할 수 있는 노드 링 스캐터넷(Node Ring Scatternet:NRS) 알고리즘을 제안하였다. 이 알고리즘은 초기 형성과 재형성 부분으로 구성이 되어 있다. 초기 형성과 관련되어 제한적 SEEK/SCAN 알고리즘을 제안하였고, 재형성과 관련되어서는 DIAC 알고리즘과 예약 복구 노드(Reserved Recovery Node) 알고리즘을 제안하였다. 또 실제 시스템 상에서 스캐터넷 알고리즘을 운용하기 위한 SFMP(Scatternet Formation & Management Protocol)을 설계하고, 상용 블루투스 하드웨어로 구현을 하여 20개의 디바이스까지의 스캐터넷 실험을 수행하였다. 실험 결과 기존의 유사 알고리즘에 비해 스캐터넷 형성 시간과 그 확률이 높은 결과를 얻었다. Bluetooth has been reputed as a wireless ad-hoc networking technology supplying scalable and extensible networks between digital devices. For that kind of networks, scatternet is a most essential part in bluetooth. But past researches on bluetooth scatternet has proposed only possibilities of scatternet algorithm based on simulation results. And many of the researches failed in guaranteeing extensibility and flexibility and had many difficulties in real hardware implementation. In this paper, we proposed node ring scatternet(NRS) algorithm guaranteeing extensible and flexible networks. NRS algorithm is designed for hardware implementation using real commercial bluetooth module. That algorithm is divided into initial formation and reformation. For initial formation, we proposed limited SEEK/SCAN algorithm. For reformation, we proposed DIAC algorithm and Reserved Recovery Node algorithm. And we proposed SFMP(Scatternet Formation & Management Protocol) in protocol stack for real implementation. NRS algorithm is operated in SFMP. Finally, we performed real hardware experiments and evaluated the proposed algorithm. In that experiments, we succeeded in forming scatternet up to 20 nodes. In comparison with other similar algorithm, proposed algorithm have the improvement in scatternet formation delay and success rate.

노드 형태에 따른 블루투스 스캐터넷 재형성 알고리즘

이한욱(Han Wook Lee),고상근(S. Ken Kauh) 한국정보과학회 2005 정보과학회논문지 : 정보통신 Vol.32 No.1

블루투스(Bluetooth)는 휴대폰을 중심으로 하여 다양한 디지털 기기 사이의 무선 인터페이스를 제공할 수 있는 기술로 가능성을 인정받아 왔다. 특히 블루투스에서 지원되는 스캐터넷(Scatternet)이라는 네트워크의 형태는 PAN(Personal Area Network)과 같은 동적인 Ad-hoc 네트워크 환경에서 블루투스가 지원되기 위해서는 필수적인 요소이다. 하지만 기존의 블루투스 스캐터넷 관련 연구들은 노드들이 수시로 추가 혹은 이탈하는 동적인 네트워크 환경을 거의 고려하지 않고 있다. 본 논문에서는 동적인 네트워크 상황을 고려하여 블루투스 스캐터넷 내부에서 노드가 이탈하였을 경우 이를 재형성하기 위한 알고리즘을 제시하였다. 본 알고리즘은 다양한 스캐터넷 형태와 무관하게 적용될 수 있는 범용 알고리즘이며, Inquiry 과정이 생략된 채 Page 과정만으로 빠르게 네트워크가 복구되는 특성을 지닌다. 또 노드의 형태에 따라 복구 마스터/슬레이브를 지정하여 작성되는 복구 노드 벡터(Recovery Node Vector)에 따라 동작한다. 또 본 논문에 제시한 알고리즘은 상용 하드웨어에 적용이 가능한 구체적인 알고리즘으로, 실제 상용 하드웨어 실험을 통해 그 성능을 평가하고 발생되는 문제점을 수정하였다. 실험을 통해 제안한 알고리즘의 재형성 지연 시간은 Inquiry 과정이 포함된 경우의 23~60% 정도로 단축된 결과를 얻었고, 97% 이상의 복구 성공률을 보였다. Bluetooth has been reputed as a wireless networking technology supplying ad-hoc networks between digital devices. In particular, bluetooth scatternet is a most essential part for dynamic ad-hoc networks. But past researches on bluetooth scatternet has hardly treated dynamic scatternet environment. In this paper, we proposed a scatternet reformation algorithm for the case that some nodes escape from the scatternet. The proposed algorithm is a general algorithm which can be applied to many types of bluetooth scatternet regardless of the topology. The proposed algorithm has short reformation time delay because the process has only page process (not including inquiry process). The algorithm is operated based on Recovery Node Vector which is composed of Recovery Master and Recovery Slave. In this paper, we performed the real hardware experiments for evaluating the performanec of the proposed algorithm. In that experiments, we measured the reformation time and reformation probability. In comparison with the case including inquiry process, the proposed algorithm had the improvement in reformation time delay and we obtained high success rate over 97%.

실차 엔진에 적용 가능한 이중 질량 플라이휠의 변위 측정 시스템 개발

이호현(Hohyun Lee),고상근(S. Ken Kauh) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The Dual Mass Flywheel (DMF) is used in many modem vehicles to decrease noise and absorb vibration on the move. By the two decoupled masses of the flywheel are linked by spring dampers, torsional vibration can be reduced. The measurement of angular displacement of DMF is very important to analysis power transmission characteristics between the engine and the transmission. To get the real time displacement data of DMF, sensor based on the principle of LVDT is mounted on rotating flywheel. The power for circuit is supplied using a method of electromagnetic induction. In addition Bluetooth technology is used for wireless data transmission.

상사 모델과 전산 수치 해석을 이용한 diffuser/nozzle pump의 정상 상태에 대한 연구

박성훈(Sung Hoon Park),고상근(Kauh S. Ken) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Recently, as the semiconductor production technology develops, there has been growing interest in the cooling system using micro fluid pump. Among the various types of micro fluid pump, the valve-less diffuser/nozzle has been extensively studied in recent years. However, the flat-walled diffuser/nozzle flow has not been clearly looked into due to its non-linear characteristics. In this paper, the flow characteristics of the flat-walled diffuser/nozzle have been analyzed using similitude model and simulations. Similitude models are designed so that the flow pattern is same as that of 1/10 scale flow by using high viscous fluid as working fluid. The results are compared to the simulations. It is shown that the flow characteristics of 2D simulation are different from 3D simulations at high Re region, and the measured pump efficiency is highly dependent on the pressure difference as well as the channel geometry. From these results, the desirable conditions for the efficient pump is discussed.

Efficiency analysis of the diffuser/nozzle fluid pump on the steady laminar flow region using 3D simulations and experiments

박성훈(Sung Hoon Park),고상근(Kauh. S. Ken) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

Recently, as the semiconductor production technology develops, there has been growing interest in the cooling system using micro fluid pump. Among the various types of micro fluid pump, the valve-less diffuser/nozzle has been extensively studied in recent years. However, the flat-walled diffuser/nozzle flow has not been clearly looked into due to its non-linear characteristics. In this paper, the flow characteristics of the flat-walled diffuser/nozzle have been analyzed in the various channel geometries and pressure boundary conditions at the laminar flow region. From these results, the geometries and boundary conditions for the efficient pump operations are investigated, and modified variables are adjusted as the parameters of the pump efficiency. The experiments are conducted based on the similitude method, and the results are compared to the simulations. It shows that the desirable condition does exist for the efficient diffuser/nozzle pump operation.

자동 변속 차량의 실차 측정이 가능한 원판형 토크미터의 개발

이준용(Junyong Lee),고상근(S. Ken Kauh),하경표(Kyoung-Pyo Ha) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_1

Torque is a key factor of engine performance. It is distributed to various parts of the vehicle such as valve-train, power-train, generator and water pump. However, the exact torque of each part cannot be determined. To find the exact torque of a part, a new type of torque meter is needed because almost all of existing torque meter type is axial which cannot be installed in a real vehicle. This paper, will discuss the development of the disk-type torque meter which can be installed in real vehicle. It makes use of the elastic deformation of the drive plate. It consists of a strain node, power node and telemetry node. To transmit torque data, Bluetooth technology is used. The disk-type torque meter was installed in a Hyundai New Avante XD and the torque was measured successfully.