• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.21-29
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• 2001

For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful devise as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. In this paper, the aerodynamic characteristics of the side jet devise itself are examined in terms of key parameters such as the side jet nozzle contour, the chamber pressure and temperature. Specifically attention is focused on the effect of the chamber shape between the straight nozzle and the bended nozzle by 90 degrees. The flow properties as well as the thrust level are compared between the two shapes. Particular attention is paid at the way the nozzle is bended at the joint. Effects of the length and the divergence angle of the nozzle on the thrust magnitude are also quantified among the three different side jet nozzles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.604-608
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• 2007

The INM simulation program is used to estimate the condition of the exposed area to the noise near a military airport in Korea. $WECPNL_k$, the evaluation unit of korean airport noise, is different from the ICAO $WECPNL_I$ that is used in the simulation program. Therefore, it is inappropriate to compare these units each other directly. This study presents method of comparison between them by using $LA_{MAX}$. The aircraft events are classified into three classes, as departure, overfly and approach. In result, the measurement and simulation seemed to be similar at departure and approach pattern. However, overfly pattern had higher errors between measurement and simulation. Finally, it is necessary to examine the method to determine flight events and duration for the $WECPNL_k$ application.

• ETRI Journal
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• 제27권2호
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• pp.172-180
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• 2005

Image resampling according to epipolar geometry is an important prerequisite for a variety of photogrammetric tasks. Established procedures for resampling frame images according to epipolar geometry are not suitable for scenes captured by line cameras. In this paper, the mathematical model describing epipolar lines in scenes captured by line cameras moving with constant velocity and attitude is established and analyzed. The choice of this trajectory is motivated by the fact that many line cameras can be assumed to follow such a flight path during the short duration of a scene capture (especially when considering space-borne imaging platforms). Experimental results from synthetic along-track and across-track stereo-scenes are presented. For these scenes, the deviations of the resulting epipolar lines from straightness, as the camera's angular field of view decreases, are quantified and presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.888-893
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• 2005

Since inertial sensor errors which increase with time are caused by initial orientation error and sensor errors(accelerometer bias and gyro drift bias), the accuracy of these devices, while still improving, is not adequate for many of today's high-precision, long-duration sea, aircraft, and long-range flight missions. This paper presents a navigation error compensation scheme for Strap-Down Inertial Navigation System(SDINS) using star tracker. To be specific, SDINS error model and measurement equation are derived, and Kalman filter is implemented. Simulation results show the boundedness of position and attitude errors.

• 한국전산유체공학회지
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• 제6권3호
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• pp.27-31
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• 2001

For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful device as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. In this paper, the aerodynamic characteristics of the side jet device itself are examined in terms of key parameters such as the side jet nozzle geometry, the chamber pressure and temperature. Specifically attention is paid to the effect of the chamber shape between the straight nozzle and the bent nozzle by 90 degrees on the nozzle flow properties. The thrust magnitudes are compared between the two shapes. Whether the way the nozzle is bent at the joint affects the nozzle performance is also investigated. Effects of the length and the divergence angle of the nozzle on the thrust are also quantified among three different side jet nozzles.

• 천문학회보
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• 제36권2호
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• pp.85.1-85.1
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• 2011

The magnetic field at the surface of the Sun is concentrated in magnetic features that often have spatial extents of 100 km or less. The study of the fine scale structure of the Sun's magnetic field has been hampered by the limited spatial resolution of the available observations. This has recently changed thanks to various new high-resolution facilities, among them the SUNRISE observatory, built around the largest solar telescope to leave the ground, and containing two science instruments. SUNRISE successfully had its first long-duration science flight on a stratospheric balloon in June 2009 and a host of scientific results have been obtained from the data. After a brief introduction to the Sunrise mission, an overview of selected results obtained so far will be given. A reflight at higher solar activity is currently being prepared.

• 한국군사과학기술학회지
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• 제13권1호
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• pp.36-40
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• 2010

In this paper, the well-known LOB-based emitter localization using linear LSE algorithm is numerically implemented and the heuristic guidelines for the parameter values to achieve 1% RMS error are presented. In the simulation, we changed the total observation durations for LOB measurements, time interval between successive LOB measurements and sensor trajectories. The effects of the time interval of LOB measurements, the time duration of the LOB measurements and the angle of flight path arc on the performance are illustrated. The dependence of the performance on the various parameters is investigated and rule-of-thumbs for the parameter values corresponding to 1% RMS error are presented for each simulation condition.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.426-432
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• 2017

충격에 의한 초소형 EFI 착화기의 기폭 성능을 규명하기 위하여 초소형 비행편 충돌 시 발생되는 고체 내 충격 감쇠에 대한 실험 및 수치해석을 수행함으로써 비행편의 충돌 속도와 하중을 계산하였다. 본 연구를 통하여 비행특성에 따른 충격파 강도 및 지속 시간을 결정함으로써 초소형 파이로테크닉 장치의 착화를 위한 비행편의 임계 속도의 예측 가능성을 확인하였다.

• 전기의세계
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• 제29권2호
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• pp.118-128
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• 1980

The properties of plasmas produced by high power glass laser were investigated with various methods of diagnostics. Electron temperature was estimated by measurement of soft X-ray, and ion temperature was estimated by measurement of the time-of-flight of ion. The measurement of incident and reflected laser light, and Schlieren and shadowgragh methods were also used. No influence of laser pulse duration on the temperature was observed in the case of durations 2, 4 and 10 nsecs. The effective heating of plasma occurred in about 2 nsec of beginning of incident laser pulse. The experimental results for fast rising laser pulse were discussed and the influence of resetime of laser pulse on the heating of plasma was described. Neutrons produced by irradiating laser beam to solid deuterium target were detected.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.362-363
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• 2007

The transport property of stabilized amorphous selenium typical of the material used in direct conversion x-ray imaging devices was studied using the moving photo-carrier grating (MPG) technique and time-of-flight (TOF) measurements. For MPG measurement, the electron and hole mobility, and recombination lifetime of a-Se films with arsenic (As) additions have been obtained. For TOF measurement, a laser beam with pulse duration of 5ns and wavelength of 350 nm was illuminated on the surface of a-Se with thickness of $400{\mu}m$.