• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.163-168
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• 2011

Noise map is drawn up under launch environment through analyzing jet noise of guided weapon in this research. This has an important significance in terms of having an opportunity to look at influence of noise which is caused by guided weapon in the surrounding environment. In this paper, the magnitude of jet noise that was measured by using microphone and the result of numerical analysis that was gained by using ENPro which is environment noise prediction program are shown. At this point estimation of noise source was based on ISO 9613. Finally noise map derived from results mentioned above will become useful material when setting safety guide for protecting hearing loss of operator of weapon system in the future.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.94-100
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• 2011

In this paper, an assessment on the preliminary coupled load analysis results for advanced Low Earth Orbit Earth Observation satellite was performed. Spacecraft FE-model was converted into Craig-Bampton model consisting of mass matrix, stiffness matrix, acceleration transformation matrix, displacement transformation matrix, and it was delivered to the launch vehicle developer. Launch vehicle developer performed a coupled load analysis with launch vehicle model and spacecraft Craig-Bampton model, and the coupled load analysis results were provided to us. From the assessment on the analysis results, it was verified that spacecraft is safe under launch environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.157-164
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• 2007

Launch Interface Ring roles as connection department of satellite and launcher for to deliver all structure loads that occur from the satellite, and one of the most intensive load received parts. Especially COMS, the first Korean developing GEO satellite, needs Launch Interface Ring with Tank Support Beam because of dissymmetry fuel tanks. The purpose of this study is the suitable form decision of Launch Interface Ring at preliminary design of COMS. In this study, launch mass and design constraints are investigated. Moreover, optimization algorithm and simplification technique are used. At the beginning of this study, three types of launch interface ring were presented and finally model 3 was the lightest design for resistance of launch environment. Nevertheless, model 1 can be suggested for application to COMS because of the satellite gravity center control and ease of fabrication.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.3
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• pp.203-214
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• 2022

As the global demand for small satellites weighing less than 500 kg increases, the development and operation of dedicated small launch vehicles increase significantly. The responsiveness of a launch vehicle that puts a small satellite into a target orbit at the desired time is attracting attention. As a result, interest in the air launch is increasing in the rapid establishment of a constellation. As the demand for small satellites in south Korea increases, this study performed analyses on the applicability of an air launch vehicle using a large civil aircraft considering the geographical environment. In terms of responsiveness, mission response times were compared and analyzed for air launch vehicles and ground small and large vehicles. In addition, an air vehicle and a small ground vehicle were quantitatively compared and analyzed for the orbital insertion performance. As a result of the analysis, the air launch vehicle has limited responsiveness in Korea regarding rapid satellite constellation establishment. However, it can be an effective alternative for low inclination angle orbit insertion with the benefit of a fast turnaround time. Furthermore, the performance of the orbital injection is close to that of the ground small launch vehicle, and the high efficiency in terms of the required propellant mass is possible, so air launch can be an effective launch means for putting small satellites into orbit in Korea.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.95-105
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• 2005

The HAUSAT-2 nanosatellite which is scheduled to launch in 2008 is being developed by SSRL(Space System Research Lab.). The HAUSAT-2 STM(Structural-Thermal Model) was developed as the first system model to verify structural and thermal design margin. The qualification level vibration and thermal tests have been conducted on STM. This paper addresses the comparison of structural analysis and test results of HAUSAT-2 STM. It was shown that the natural frequency of HAUSAT-2 STM satisfies the stiffness requirements without structural damage in the random vibration test. The assembly and integration validity were also checked out through STM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.96-102
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• 2001

High intensity vibro-acoustic testing is the appropriate method for flight qualification testing of space flight vehicle which must ensure the acoustic environment of launch. Growing demand for satellites and launch vehicles in korea has resulted in a recent increase in the demand for high intensity vibro-acoustic test facility. The test facility is designed to provide an acoustic environment of 152 ㏈( re 20 ${\mu}$Pa) overall sound pressure level over the band width of 30 Hz to 10,000 Hz in the reverberant chamber. The reverberant chamber has a volume of 1,000 ㎥ with interior dimensions of 8.7m${\times}$l0m${\times}$12m, which can accommodate not only satellites but also launch vehicle payload fairing. Korea Aerospace Research Institute and Korean industries have been carrying out the development of the reverberant chamber and auxiliary devices, such as automatic control system, monitoring/safety device, and jet nozzle, etc. This paper presents the detailed description of High Intensity Acoustic Chamber of KARI, which will be the first and unique testing facility in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.33-36
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• 1999

The KOMPSAT, which is scheduled to be launched by Taurus launch vehicle in late November of 1999, will be in a sun-synchronous orbit with an altitude of 685km, eccentricity of 0.001, inclination of 98deg and local time of ascending node of 10:50 a.m. Electronics and Telecommunications Research Institute and Daewoo Heavy Industry had jointly developed a KOMPSAT Simulator as a component of the KOMPSAT Mission Control Element. The MCE had been delivered to Korea Aerospace Research Institute for the KOMPSAT ground operation. It is being used for training of KOMPSAT ground station personnel. Each of satellite subsystems and space environment were mathematically modeled in the simulator. To verify the overall function of KOMPSAT simulator, a Launch and Early Orbit Phase(LEOP) operation simulations have been performed. The simulator had been verified through various tests such as functional level test, subsystem test, interface test, system test, and acceptance test. In this paper, simulation results for LEOP operations to verify flight software adapted into simulator, satellite subsystem models and environment models are presented.

• Journal of KIISE
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• v.42 no.6
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• pp.691-698
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• 2015

Application launch time is an important performance metric to user experience in desktop and laptop environment, which mostly depends on the performance of secondary storage. Application launch times can be reduced by utilizing solid-state drive (SSD) instead of hard disk drive (HDD). However, considering a cost-performance trade-off, utilizing SSDs as caches for slow HDDs is a practicable alternative in reducing the application launch times. We propose a new SSD caching scheme which migrates data blocks from HDDs to SSDs. Our scheme operates entirely in the file system level and does not require an extra layer for mapping SSD-cached data that is essential in most other schemes. In particular, our scheme does not incur mapping overheads that cause significant burdens on the main memory, CPU, and SSD space for mapping table. Experimental results conducted with 8 popular applications demonstrate our scheme yields 56% of performance gain in application launch, when data blocks along with metadata are migrated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.929-937
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• 2008

A GPS receiver system utilized on satellite launch vehicles should operate normally under harsh environments as well as high-dynamic conditions. The GPS receiver system to use for range safety of KSLV(Korea Space Launch Vehicle)-I that is the first satellite launch vehicle developed by KARI(Korea Aerospace Research Institute) has been confirmed to survive under the environment of the launcher through extensive terrestrial tests including humidity, high and low temperatures, vacuum, sinusoidal and random vibrations, shocks, acceleration, EMI/EMC(Electromagnetic Interference/ Electromagnetic Compatibility), etc. Several performance tests have been also carried out in order to evaluate tracking capability and accuracy of the GPS receiver under high-dynamic conditions using a GPS signal simulator. Some lessons-learned during development of the GPS receiver system and its special characteristics compared with COTS(Commercial-Off-The-Shelf) GPS receiver systems are described in this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.172-175
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• 2005

Since, similar to other commercial launch vehicles, various kinds of pyrotechnique devices are used in the KSLV-I(Korea Space Launch Vehicle), the electronic equipment on the vehicle equipment bay is exposed to the sever pyroshock environment during Pyrotechnique device detonation. In order to confirm the survivability of electrical instruments from these pyroshock conditions, shock tests are performed by using a pyroshock simulation during development and qualification phase. In this paper, the pyroshock simulator installed in KARI(Korea Aerospace Research Institute) are briefly introduced, and its performance of pyroshock generating is compared with the measured shock response spectrums from small scaled fairing jettisoning tests. The results show that the pyroshock simulator is still proper to generate severe pyroshocks similar to real pyrotechique detonating conditions, but the redesign on the test jigs is necessary to improve its test performance.