• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.285-288
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• 2008

Even though many modular converters have several internal protection circuit blocks for various abnormal operation conditions, there are many failure cases on modular converters at real applications. In this paper, the control strategy for failure protection of converters with internal 'In-Hibit' function is investigated. As an example, for the MDl modular converters the in-hibit function application is realized and the test results shows that adopting in-hibit function while converter switching reduces the voltage and current stress. And the reduction of switching stress on converter will decrease failure rate on converters.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.43-50
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• 2015

In order to protect important information of smart phone from these security threats, this paper has studied a mechanism for protecting information from the leakage of various information and personal information stored in the smart phone. This paper has configured the basic protection scope for the information protection and applied real time encodement when new contents were created. Also, this paper has applied a security function so that the content of the protected scope can be managed and erased remotely in preparation for loss and burglary.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.695-701
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• 2009

Side Buffer with Anti-Climber is absorber and anti climber during impact. The Overload Protection Device protects the car underframe from being damaged in case of release of the overload protection. In case of heavy impacts(60 ton), the load is converted into deformation energy by plastic deformation of the tear-off bolts This paper describes a study on this function applied for Side Buffer and Overload Protection Device.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.5
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• pp.537-544
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• 2021

Cyber threats can bypass existing cyber-protection systems and are rapidly developing by exploiting new technologies such as artificial intelligence. In order to respond to such cyber threats, it is important to improve the ability to detect unknown cyber threats by correlating heterogeneous cyber protection systems. In this paper, to enhance cyber-attack response capabilities, we proposed command and control that enables rapid decision-making and response before the attack objectives are achieved, using Lockheed Martin's cyber kill chain and MITRE ATT&CK to analyze the purpose and intention of the attacker.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.412-434
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• 2023

This study discusses the high-order diffusion method in the wavelet domain. It aims to improve the edge protection capability of the high-order diffusion method using wavelet coefficients that can reflect image information. During the first step of the proposed diffusion method, the wavelet packet decomposition is a more refined decomposition method that can extract the texture and structure information of the image at different resolution levels. The high-frequency wavelet coefficients are then used to construct the edge detection function. Subsequently, because accurate wavelet coefficients can more accurately reflect the edges and details of the image information, by introducing the idea of state weight, a scheme for recovering wavelet coefficients is proposed. Finally, the edge detection function is constructed by the module of the wavelet coefficients to guide high-order diffusion, the denoised image is obtained. The experimental results showed that the method presented in this study improves the denoising ability of the high-order diffusion model, and the edge protection index (SSIM) outperforms the main methods, including the block matching and 3D collaborative filtering (BM3D) and the deep learning-based image processing methods. For images with rich textural details, the present method improves the clarity of the obtained images and the completeness of the edges, demonstrating its advantages in denoising and edge protection.

• Convergence Security Journal
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• v.21 no.4
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• pp.77-85
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• 2021

Cyber protection is an activity that protects the information systems we operate from cyber attacks and threats. To know the level of protection of the currently operating cyber protection system, it is necessary to update the current state of attack technology by reflecting the constantly evolving cyber threats and to analyze whether it is possible to respond with the protection function. Therefore, in this paper, we analyze the relationship between the attack procedures and defense types of the cyber kill chain with the defense technology(Mitigation ID) of MITRE and present the cyber protection level for each military unit type with a focus on defensive cyber activities. In the future, it is expected that the level of cyber protection will be improved through real-time analysis of the response capabilities of cyber protection systems operating in the defense sector to visualize the level of protection for each unit, investigate unknown cyber threats, and actively complement vulnerabilities.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.84-86
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• 2005

The digital systems such as PLC or DCS have been applied to non-safety systems of nuclear power plants because of many difficulties in using analog systems. Nowadays, digital systems have been applied to safety systems of the plants such as reactor protection system. One of the main advantages of digital systems is applicability of automatic testing methods to the systems. The protection system requires high-reliability and high-availability because it shall minimize the propagation of abnormal or accident conditions of nuclear power plants. The calculation of reliability and availability of systems depends on the maintenance period of the system. In general, the maintenance period of the protection system is one-month in case of the manual test. However, the cycle of test can be shortened in several hours by using automatic periodic testing. The reliability and availability of the system is better when test period is shortened because the reliability and availability is inverse proportion to the test period. In this research, we developed the automatic periodic testing method for KNICS Reactor Protection System, which can test the system automatically without an operator or a tester. The automatic testing contained all functions of reaction protection systems from analog-to-digital conversion function of the bistable Processor to the coincident trip function of the coincident processor. By applying the automatic periodic testing to reaction system, the maintenance cost can be cut down and the reliability can be increased.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.47-58
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• 2020

Most of the reactor trips in Korean NPPs related to core protection systems were caused not because of proximity of boiling crisis and, consequently, a damage in the core, but due to particular miscalculations or component failures related to the core protection system. The most common core protection system applied in Korean NPPs is the Core Protection Calculator System (CPCS), which is installed in OPR1000 and APR1400 plants. It generates a trip signal to scram the reactor in case of low Departure from Nucleate Boiling Ratio (DNBR) or high Local Power Density (LPD). However, is a reactor trip necessary to protect the core? Or could a fast power reduction be enough to recover the DNBR/LPD without a scram? In order to analyze the online calculation of DNBR/LPD, and the use of fast power reduction as trip avoidance methodology, a concept of CPCS with fast power reduction function was developed in Matlab® Simulink using systems engineering approach. The system was validated with maximum of 0.2% deviation from the reference and the dynamic deviation was maximum of 12.65% for DNBR and 6.72% for LPD during a transient of 16,000 seconds.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.691-697
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• 2003

This paper proposes a current differential relay for transformer protection that operates in accordance with a blocking method based on the difference-function of a differential current. For magnetic inrush and over-excitation, discontinuities in the first-difference function of the differential current arise at the points of inflection, which correspond to the start and end of each saturation period of the core. These discontinuities are converted into the pulses in the second- and third-difference functions of the differential current. The magnitudes of the pulses are large enough to detect saturation of the core. A blocking signal is issued if the magnitude of the third-difference function exceeds the threshold and is maintained for three quarters of a cycle. The performance of the relay is assessed under various conditions with magnetic inrush, internal faults and external faults. The proposed blocking method can improve significantly the operating time of a relay and achieve high sensitivity of a relay.

• Animal Bioscience
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• v.36 no.1
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• pp.144-155
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• 2023

Objective: Adipocyte differentiation is regulated by a variety of functional genes and noncoding RNAs. However, the role of miRNAs in lipid deposition of goat white adipose tissue is still unclear. Therefore, this study revealed the miRNA expression profile in goat subcutaneous adipocytes by sRNA-seq. Methods: The miRNA expressed in goat subcutaneous preadipocytes and the mature adipocytes were sequenced by sRNA-seq. The differentially expressed miRNAs (DEm) were screened and gene ontology (GO) and Kyoto encyclopedia for genes and genomes (KEGG) analyses were performed. Gain-of-function and loss-of-function combined with oil red O staining, Bodipy staining, and quantitative reverse-transcription polymerase chain reaction (qPCR) were utilized to determine the effect of miR-133a-3p on adipocyte differentiation. Results: A total of 218 DEm were screened out. The target genes of these DEm were significantly enriched in GO items such as biological regulation and in KEGG terms such as FAK signaling pathway and MAPK signaling pathway. qPCR verified that the expression trend of miRNA was consistent with miRNA-seq. The gain-of-function or loss-of-function of miR-133a-3p showed that it promoted or inhibited the accumulation of lipid droplets, and CCAAT enhancer binding protein α (C/EBPα) and C/EBPβ were extremely significantly up-regulated or down-regulated respectively (p<0.01), the loss-of-function also led to a significant down-regulation of peroxisome proliferator activated receptor gamma (PPARγ) (p<0.01). Conclusion: This study successfully identified miRNAs expression patterns in goat subcutaneous adipocytes, and functional identification indicates that miR-133a-3p is a positive regulator of the differentiation process of goat subcutaneous adipocytes. Our results lay the foundation for the molecular mechanism of lipid deposition in meat-source goats from the perspective of miRNA.