• Transactions on Electrical and Electronic Materials
• /
• v.18 no.1
• /
• pp.16-20
• /
• 2017

A RF-MEMS (radio-frequency microelectromechanical-system) based DPDT (double pole double throw) switch for the Ku band has been designed and analyzed for this article. The switch topology is based on the FG-CPW (finite ground-coplanar waveguide) configuration of a microstrip-transmission line. An FEM-based multiphysics solver is used for the evaluation of the spring constant, stress distribution, and pull-in voltage regarding the requirements of the switch-beam unit. The electromagnetic performance of the switch is investigated for a $675{\mu}m$ thick silicon substrate. For the operational frequency of 14.5 GHz, an insertion loss better than -0.3 dB, a return loss better than -40 dB, and input/output- and output-port isolations better than -35 dB are achieved for the switching unit.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09b
• /
• pp.104-112
• /
• 2010

The thermal influential factor of energy pile system is investigated by considering the seasonal effect, saturation of ground, and fluid velocity based on the finite volume method. Analysis includes the evaluation of thermal resistance and corresponding heat exchange rate for each case. It is shown that the efficiency of heat exchange rate is more pronounced with higher fluid velocity due to the larger number of circulation for a given period. Through the parametric studies, it is also found that the degrees of saturation a little influenced thermal effect during 8 hours of operational scenario.

• Journal of the Korean Society of Systems Engineering
• /
• v.1 no.1
• /
• pp.46-52
• /
• 2005

The Tactical Data Link System(TDLS) is a standardized communication link to exchange and interface positional, situational information, command and control in real time. It has been evalua ted that the link would play an important role for tactical interoperability, situation awareness, and execution of joint operations in the future war. But considering the rapidly changing war situations, even though being admitted the necessity of the TDLS of Army helicopter, one of superpowers in the Army, it is not yet built the detailed operational concept. Therefore, this work presents how to embody the TDLS through the systems engineering approach based on the TDLS operating concept analysis of helicopters-ground units.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.1 s.20
• /
• pp.56-61
• /
• 2005

A novel method for telemetering flight operational data of airborne jammer to ground station is presented. The design and construction of an onboard telemetry transmitting set and a ground receiving set which are necessary for realizing this novel method is described. Using this novel method, ALQ-X, airborne jammer, can immediately transmit the gathered data during flight without additional exclusive telemetry set.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1052-1054
• /
• 2003

RAZAKSAT is a second micro-satellite mission by Malaysian Satellite Program and is expected for launch in June 2004. Designed to orbit the earth at low-equatorial orbit, RAZAKSAT will meet Malaysia’s immediate needs to rapid data acquisition (real time and more repetitions) to address many operational issues of remote sensing applications, which require availability of current data sets. RAZAKSAT will be among the first remote sensing satellite to orbit the earth at low inclination along the equator, 9$^{\circ}$ with 685km altitude, hence, allows optimal geographical information and environment change within equatorial region be observed with a unique revisit characteristics. The satellite primary payload is MAC, a push-broom type camera with 2.5m of ground sampling distance (GSD) in panchromatic band and 5m of GSD in four multi-spectral bands. This paper describes on the variation of illumination anticipated from simulated RAZAKSAT image, examine its implication to its ground leaving radiances for major applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1020-1025
• /
• 2001

Vertical canned pumps are usually applied in the power plant to transport fluids that the available suction pressure is low at the condensate system and the circulating-water system. The top of the motor driver is 5.5m above the base and the barrel and drop column extend even further below the ground. While this size and configuration may produce an efficient pumping system, it also introduces several dynamic problems which must be considered in order to obtain a reliable operation. The main problem is that the vibrational mode of the long flexible cantilever structure above the ground exist near the operational characteristics of the condensate debris system. This system's trouble has been showed at 2,086 hp condensate water loading pumps in a nuclear power plant.

• Earthquakes and Structures
• /
• v.16 no.3
• /
• pp.321-327
• /
• 2019

This study investigated the possibility of using the recorded micro tremor data on ground level as ambient vibration input excitation data for investigation and application Operational Modal Analysis (OMA) on the bench-scale earthquake simulator (The Quanser Shake Table) for model chimney. As known OMA methods (such as EFDD, SSI and so on) are supposed to deal with the ambient responses. For this purpose, analytical and experimental modal analysis of a model chimney for dynamic characteristics was performed. 3D Finite element model of the chimney was evaluated based on the design drawing. Ambient excitation was provided by shake table from the recorded micro tremor ambient vibration data on ground level. Enhanced Frequency Domain Decomposition is used for the output only modal identification. From this study, best correlation is found between mode shapes. Natural frequencies and analytical frequencies in average (only) 1.996% are different.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.821-826
• /
• 2002

The KOMPSAT-2 DCSU(the data compression & storage unit) performs the acquisition of image data from cameras, the compression with requested compression rate, the storage with specified file ID on the mission command and the distribution to the assigned DLS(Data Link System) channels per the mission and operation requirements. The worldwide observation using the MSC is able to be achieved by this DCSU's behavior. This paper presents the features of KOMPSAT-2 DCSU and provides proper ground operation concept after launch.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1102-1104
• /
• 2003

KOMPSAT-2 provides two different imaging methods, direct imaging and playback imaging. For playback imaging operation KOMPSAT-2 has a storage device called DCSU (Data Compression & Storage Unit) to hold images taken before. Compression function is necessary to save memory space and data transmission time to ground station. There are several parameters for compression like compression ratio. Due to DCSU architectural characteristics and KOMPSAT-2 operational limitations, there are some restrictions on selecting compression parameters. This paper will provide selecting guides on compression parameters.

• Aerospace Engineering and Technology
• /
• v.7 no.1
• /
• pp.229-235
• /
• 2008

The ground flight termination system(GFTS) could be used for the termination of launch vehicle in flight motion when the launch vehicle deviates from the designated route due to the system malfunction or failure as well as the launch vehicle can't be tracked by the ground tracking system. This paper introduces the basic concept and design of the ground flight termination system to be used for KSLV launch mission in NARO space center. In order to design the optimal ground flight termination system for KSLV launch application, the operational concept reflected on the flight trajectory and system characteristics of KSLV launch vehicle should be considered. Moreover the RF link budget analysis, and the analysis for system availability and reliability are done. Based on the analysis above, the each subsystem of ground flight termination to transmit the termination signal in stable is designed for KSLV launch mission.