• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.463-468
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• 2007

The abnormal sound of generator frame is analyzed by a acceleration signal. The spike-like time signal is major characteristics of impacting force. The distributional map of vibration level is one of visualization method. With map, noise source was easily detected. After de_assembly of generator, loose part of internal component is the source of impact force by mechanical movement of stator inherently. In contact condition of part with clearance, the level of impact signal is different at each revolution and impact signal did not happens periodically.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.490-490
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• 2013

In semiconductor industry, it is expected that plasma process which use 450 mm source will be used at next generation. However, main obstacle of the large area plasma source is plasma uniformity from it. When electrode is enlarged, field difference between center area and side area reduces the plasma uniformity [1-3]. Therefore we investigate multi-electrode which diminish this field difference.We designed two multi-electrode models. One has two segments and the other has five segments. Each multi-electrode model is connected with two power generator and two matchers. One generator and one matcher is connected with center electrode part. The other one generator and the other one matcher is connected with side electrode part. The ion density is measured at 29 points by using floating harmonic method [4-6]. After measuring the data of each multi-electrode model, we discuss the difference of profile between two models' data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.755-759
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• 2012

In this paper, it is about random number generator, which is based on hardware is utilized in medical science and game area. The Intel presents guideline of security level about hardware based true random number generator. At hardware based random number generator, the various test items, that are included in test suits as NIST statistical test, FIPS140-1, is applied. In this paper, it experiments about degree extent of randomness variation from filter scheme effects, which is applied in output stream of hardware noise source.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2192-2201
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• 2016

Wind energy is currently the fastest-growing electricity source worldwide. The cost efficiency of wind generators must be high because these generators have to compete with other energy sources. In this paper, a system that utilizes an open-winding permanent-magnet synchronous generator is studied for wind-energy generation. The proposed system controls generated power through an auxiliary voltage source inverter. The VA rating of the auxiliary inverter is only a fraction of the system-rated power. An adjusted control system, which consists of two main parts, is implemented to control the generator power and the grid-side converter. This paper introduces a study on the effect of unbalanced voltages for the wind-generation system. The proposed system is designed and simulated using MATLAB/Simulink software. Theoretical and experimental results verify the validity of the proposed system to achieve the power management requirements for balanced and unbalanced voltage conditions of the grid.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.397-403
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• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• ETRI Journal
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• v.42 no.4
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• pp.518-526
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• 2020

This paper presents an efficient hardware random-number generator based on a beta source. The proposed generator counts the values of "0" and "1" and provides a method to distinguish between pseudo-random and true random numbers by comparing them using simple cumulative operations. The random-number generator produces labeled data indicating whether the count value is a pseudo- or true random number according to its bit value based on the generated labeling data. The proposed method is verified using a system based on Verilog RTL coding and LabVIEW for hardware implementation. The generated random numbers were tested according to the NIST SP 800-22 and SP 800-90B standards, and they satisfied the test items specified in the standard. Furthermore, the hardware is efficient and can be used for security, artificial intelligence, and Internet of Things applications in real time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.53-57
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• 2008

Diesel generator is most widely used for supplying of emergency electrical power. There have been extensive research efforts to develop ways to Ensure stable electrical power delivery to the loads using hybrid power sutures, such as power source, storage batteries, fuel cells and solar cells. Furthermore, as the role of these diesel generators for emergency electrical power supply has recently become very important, they should assure high reliability and flexibility according to the operation load. Therefore, in this paper, we introduce a controller to be used in diesel generator toenable tracking control of maximum power according to the load variation and suppressing high-order harmonics while maintaining stable frequency.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.109-115
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• 2004

The micro turbo generator is new portable power source based on the Brayton cycle, which consists of a compressor, a turbine, a generator, and a combustion chamber. In this paper, the thermodynamic analysis was performed to find the required condition for hundreds watts power in the micro turbo generator, and also the rotordynamic stability was predicted using the numerical analysis of air foil bearings which support the micro turbo generator. By experimental works, the rotordynamic stability of the micro turbo generator with foil bearings was verified. While various transient dynamic situation, the micro turbo generator had stable performances. From the result, it was demonstrated that air foil bearings could be adapted to the micro turbo generator as a excellent lubrication element.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1441-1453
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• 2024

The yield stability of the neutron generator directly affects the accuracy of elemental analysis. This paper presents an industrial fully automatic neutron generator with a 48 mm neutron tube based on PLC to improve the stability and reliability of the neutron generator in industrial applications. By integrating a Kalman Filter with the PID algorithm in a PLC, the neutron yield of the generator is remarkably stabilized, achieving 1 × 10⁸n/s. The neutron generator has been employed for industrial online elemental analysis. The results demonstrate that only a slight fluctuation of ±0.82 % exists in the neutron yield, and the reproducibility of the generator holds at a significant level of 0.05. This improved neutron generator can be applied to the online bulk analysis of carbon in coal-fired power stations and absolute measurement of neutron source emission rate.

• Convergence Security Journal
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• v.20 no.2
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• pp.69-76
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• 2020

Blockchain 2.0 supports programmable smart contract for the various distributed application. However, the environment of running smart contract is limited in the blockchain, so the smart contract only get the deterministic information, such as block height, block hash, and so on. Therefore, some applications, which requires random information, such as lottery or batting, should use oracle service that supply the information outside of blockchain. This paper develops a random number generator oracle service. The random number generator oracle service use irregular big data as entropy source. This paper tests the randomness of bits sequence generated from oracle service using NIST SP800-22. This paper also describes the advantages of irregular big data in our model in perspective of cost comparing hardware entropy source.