• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.461-464
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• 2012

The high-frequency data acquisition system of the rocket engine test facility has been updated to perform hot-firing tests of 7 ton-class liquid rocket engine combustion chambers which will be used for the third stage of the Korea space launch vehicle II. The paper deals with the design of the updated high-frequency data acquisition system and explains its main functions.

• Proceedings of the KSR Conference
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• 2003.10a
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• pp.210-215
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• 2003

Korean High Speed Train (KHST) has been tested on high speed line in JungBu site since it was developed in 2002. The KHST figured 7 cars was modeled for dynamic simulation with Vampire program. and the data acquisition system was used to test successfully the on-line test for proving the dynamic performance of KHST. The comparison between test and simulation results for dynamic behavior of KHST was tried in this paper and it was very difficult because the environmental conditions and running conditions have an effect on the test results and these conditions are unable to be modeled for dynamic analysis. Also the parameters for data acquisition system for test are usually not same to simulation conditions. Therefor, in this paper the acceleration data after filtering with low pass filter below 1Hz were used to compare between test and simulation results because the low frequency range is useful to evaluate the dynamic performance for railway vehicle system, so as steady state curving acceleration. The results show that both are similar in low frequency range.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.709-711
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• 2005

Developing fault location system for underground power cable which can detect its fault location exactly require very high speed data acquisition and signal processing capability. We are developing fault location system which is different from conventional fault locator. This fault location system monitor underground power cable by using on-line speed current sensor and if there are an accident, it record its transient signal and calculate fault location by analyzing it. Signals which acquired when power cable fault arise, showed transient characteristics and its frequency band is very hish. So, to develop fault location system, we designed special high speed data acquisition and signal processing board. In this thesis, we describe on data acquisition and signal processing H/W design for fault location system on underground power cable.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.47-52
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• 2016

This paper describes the design and fabrication of high frequency ground impedance measuring system for assessment of grounding system for Lightning protection. The ground impedance measuring system has been designed and fabricated which makes it possible to assess the ground impedance by frequency ranges from 100 Hz to 1 MHz. The effective grounding systems having a very low impedance to electromagnetic disturbance such as lightning surges and noises in microelectronics and high-technology branches are strongly required. In order to analyze the dynamic characteristic of grounding system impedances in lightning and surge protection grounding systems, it is highly desirable to assess the ground impedances as a measure of performance of grounding system in which lightning and switching surge currents with fast rise time and high frequency flow. The measuring system is based on the variable frequency power supply and consists of signal circuit part, main control part, data acquisition and processing unit, and voltage and current probe system. The ground impedance measuring system can be used to assess grounding system during occurrence of lightning.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.363-365
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• 2002

The characteristic responds of load respect to various disturbances which can usually be occurred on actual power system is very important to analyze performance and to improve load with high-technology. The disturbance power supply is designed to provide wide range of power to testing load. This device uses PLC technology to dynamic characteristic experiment and CVVF to change frequency. Also this instrument includes data acquisition system to obtain reliable data from experiment.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.62-68
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• 2000

It was designed a high-speed analog input card that is a important device of ultrasonic testing flaw detector in the middle of non-destructive testing in this Paper. The A/D Board is inquired high-speed sampling rate and fast data acquisition system. This pater shows a design that has a function of Peak- Detection for ultrasonic testing by ISA Bus type and a 50MHz of A/D converter in order to do sampling more than quadruple frequency of transducer frequency.

• Wind and Structures
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• v.31 no.1
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• pp.21-29
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• 2020

The wind field measurement of severe winds such as hurricanes (or typhoons), thunderstorm downbursts and other gales is important issue in wind engineering community, both for the construction and health monitoring of the wind-sensitive structures. Although several wireless data transmission systems have been available for the wind field measurement, most of them are not specially designed for the wind data measurement in structural wind engineering. Therefore, the field collection is still dominant in the field of structural wind engineering at present, especially for the measurement of the long-term and high-frequency wind speed data. In this study, for remote wind field measurement, a novel wireless long-term and high-frequency wind data acquisition system with the functions such as remote control and data compression is developed. The system structure and the collector are firstly presented. Subsequently, main functions of the collector are introduced. Also novel functions of the system and the comparison with existing systems are presented. Furthermore, the performance of this system is evaluated. In addition to as the wireless transmission for wind data and hardware integration for the collector, the developed system possesses a few novel features, such as the modification of wind data collection parameters by the remote control, the remarkable data compression before the data wireless transmission and monitoring the data collection by the cell phone application. It can be expected that this system would have wide applications in wind, meteorological and other communities.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.19-25
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• 2019

To detect the impact location of a structure, the authors' group conducted a study on piezoelectric paint sensor. The piezoelectric paint sensors are used for impact detection due to their inherent characteristics: sensitivity to high-frequency signal and impact. Additionally, the paint sensor can be applied on curved and complex structures where ceramic sensor would not be applicable. Moreover it is a self-powered sensor therefore no need for an external power source. For impact localization, mosaic pattern electrodes were coated on the specimen and the impact signal obtained from any part of the electrode where the impact occurred. If we more precise impact localization is required, the electrodes should be divided into more parts and impact data acquisition conducted in all the points of the electrode. In this paper, we developed a light, cheap and simple multi-channel data acquisition system to aid in data gathering. In total four channels data acquisition have been tested using the ARM Cortex-M3.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1454-1462
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• 2008

This paper is focused on the analysis of the noise and vibration measured near the wheelset of the high-speed trains using a time-varying frequency transform as a preliminary research of running monitoring. Due to the non-stationary characteristics, it is necessary to examine noise and vibration of the train with time-varying frequency transforms. In this paper, the short-time Fourier transform method is utilized - the stored data is localized by modulating with a window function, and Fourier transform is taken to each localized data. For the examination, the non-stationary noise and vibration of the high-speed train's wheelset are measured by using some microphones and accelerometers, and those signals are stored in a on-board data acquisition system. The non-stationary random signal analyses with the short-time Fourier transform are performed, and the result are classified as follows; auto-spectral density, cross-spectral density, frequency response, and coherence functions. From those functions, it is possible to observe the frequency characteristics of sleepers, switchers, tunnels, and steel bridges. Also, some distinct peaks, which are not dependent upon the train's speed, are identified from the results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.130-136
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• 2002

In this paper, a flight test method is described for the system identification of the unmanned aerial vehicle equipped with an automatic flight control system. Multistep inputs are applied for both longitudinal mode and lateral/directional excitation. Optimal time step for excitation is sought to provide the broad input bandwidth. A programmed mode flight test method provides high-quality flight data for system identification using the flight control computer with the longitudinal and lateral/directional autopilot which enables the separation of each motion during the flight test. In addition, exact actuating input that is almost equivalent to the designed one guarantees the highest input frequency attainable. Several repetitive flight tests were implemented in the calm air in order to extract the consistent system model for the air vehicle. The enhanced airborne data acquisition system endowed the high-quality flight data for the system identification. The flight data were effectively used to the system identification of the unmanned aerial vehicle.