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최시홍,Choi, SiHong 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.4
In this paper, This study shows the content on the impact fuze test and the measurement using underwater explosion phenomena. The impact fuze has both a delay function and a super quick. Up to now, nothing but the naked eye of the observer has been used to verify performance of the impact fuze. The observer has determined the performance by the shape of the plume created from the explosion phenomenon. However, it is extremely difficult to use that method at a long range. In order to solve the problem, the measurement using the underwater explosion phenomena was tried.
Increase of Side-lobe Level Difference of Spherical Microphone Array by Implementing MEMS Sensor
Jaehyung Lee(이재형),Sihong Choi(최시홍),Jong-Soo Choi(최종수) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.4
본 논문은 구형 마이크로폰 어레이의 부엽 레벨의 차를 증가시키기 위한 방법에 대한 연구 내용을 다루었다. 일반적인 어레이 신호처리에서 마이크로폰을 조밀하게 배치함으로써 어레이 응답에서의 주엽과 부엽 간의 차이를 늘릴 수 있고 어레이의 소음원 판별능력을 증가시킨다. 최근 사용되고 있는 상용 에레이들은 제작 단가와 어레이의 크기 때문에 센서의 수를 늘리는데 한계를 보이고 있다. 이런 문제를 극복하기 위해 본 연구에서는 MEMS 센서를 이용하여 구형 어레이에 적용하였다. 구형 마이크로폰 어레이를 이용한 시뮬레이션과 실험을 통해 정현파 소음원을 측정하였다. 실험을 위해 32 개의 일반 측정용 마이크로폰을 이용한 어레이와 85 개의 MEMS 마이크로폰을 이용한 구형 어레이를 제작하였다. 구형 조화 분해기법과 빔형성기법을 이용하여 측정 데이터를 분석하였다. 2 kHz 이상의 소음원에 대하여 MEMS 마이크로폰 어레이가 4 dB 이상의 부엽 저감 능력을 가지는 것을 확인하였다. A method for increasing the difference of side-lobe level in spherical microphone array is presented. In array signal processing, it is known that narrow interval between sensors can increase the difference between main lobe and side-lobe of array response which eventually increase the source recognition capability. Recent commercial array being used, however, have shown certain limitation in using the number of sensors due to its costs and geometrical size of array. To overcome this problem, we have adapted MEMS sensors into spherical microphone array. To check out the improvement, two different types of spherical microphone array were designed. One array is composed with 32 regular instrument microphones and the other one is 85 MEMS sensors. Simulation and experiments were conducted on a sinusoidal noise source with two arrays. The time history data were analyzed with spherical harmonic decomposition and beamforming technique. 85 MEMS sensors array showed the improved side-lobe level suppression by more than 4 dB above the frequency content of 2 kHz compared to 32-sensor array.
김응수(Kim Eungsu),서일환(Seo Ilhwan),최시홍(Choi Sihong),박종세(Park Jongse) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10
The firing noise produced at artillery test range or military training ground is impulsive burst noise which energy is generated within tens of milliseconds and distributed an isolated burst of sound energy separated to one by one noise. The long range propagation of this noise is affected by a caliber of gun, amount of propellant, distance between source and receiver, ground and meteorological condition. In this paper, main influence parameters have been described based on experimental analysis of measured data. It is considered that this analysis result can be used as useful materials for study of effective firing noise management and development of propagation model.
차량 주행성능 분석을 위한 자료 획득 장치 개발에 관한 연구
선우명호(Myoungho Sunwoo),이재인(Jaein Lee),이우택(Wootaik Lee),이상준(Sangjun Lee),주원철(Wonchul Ju),최시홍(Sihong Choi),이상태(Sangtae Lee),이현수(Hyunsoo Lee),이경민(Kyungmin Lee) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1
To evaluate the powertrain performances and driving behavior of a vehicle, it is necessary to survey the driving patterns, which have influences on fuel economy and emissions.<br/> The driving patterns are depended on the driver's habit and the road and traffic conditions. An in-vehicle data acquisition system, which is called Mode Survey System(MOSS), is designed and developed to analyze the driving patterns of the actual driver. Furthermore MOSS would be able to make a common driving mode to be used in emission, fuel efficiency, shift survey, catalyst durability, and other tests using the analyzed driving patterns.<br/> MOSS is a stand-alone system based on the 68HC11 MCU. It mainly consists of an MCU-based Hardware and a PC-based software. MOSS logs various data relating to powertrain and vehicle driving such as vehicle speed, engine RPM, gear position, brake, clutch, fuel consumption, and others. For analysis of the driving data, MOSS software, which is easy to use, can be used to analyze the driving patterns. Both the real-time processing and the post processing function for driving data analysis are available.<br/>