• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.773-779
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• 2021

CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.11-16
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• 2021

The importance of software is increasing due to the development of information and communication, and software copyright disputes are also increasing. In this paper, the source of the submitted programs and the files necessary for the execution of the program were taken as the scope of analysis. The large-capacity file transfer solution program to be analyzed provides additional functions such as confidentiality, integrity, user authentication, and non-repudiation functions through digital signature and encryption of data.In this paper, we analyze the program A, program B, and the program C. In order to calculate the program similarity rate, the following contents are analyzed. Analyze the similarity of the package structure, package name, source file name in each package, variable name in source file, function name, function implementation source code, and product environment variable information. It also calculates the overall similarity rate of the program. In order to check the degree of agreement between the package structure and the package name, the similarity was determined by comparing the folder structure. It also analyzes the extent to which the package structure and package name match and the extent to which the source file (class) name within each package matches.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.209-214
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• 2023

In the future, as autonomous vehicles become popular at home and abroad, the frequency of accidents involving autonomous vehicles is also expected to increase. In particular, when a fully autonomous vehicle is operated, various criminal/civil problems such as sexual violence, assault, and fraud between passengers may occur as well as the vehicle accident itself. In this case, forensics for accidents involving autonomous vehicles and accidents involving passengers in the vehicles are also about to change. This paper reviewed the types of security threats of autonomous vehicles, methods for maintaining the integrity of evidence data using blockchain technology, and research on digital forensics. Through this, it was possible to describe threats that would occur in autonomous vehicles using blockchain technology and forensic techniques for each type of accident in a scenario-type manner. Through this study, a block that helps forensics of self-driving vehicles before and after accidents by investigating forensic security technology of domestic and foreign websites to respond to vulnerabilities and attacks of autonomous vehicles, and research on block chain security of research institutes and information security companies. A chain method was proposed.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.103-114
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• 2022

In the area of construction defects, residents have a tendency to focus on visually identifiable defects, while construction companies focus on defects that affect the structural and functional integrity of apartment housing. Accordingly, construction companies and residents have conflicting views on defects in apartment housing. To address this issue, this study aimed to accurately identify the main disputes surrounding defects in multi-family housing complexes or multi-dwelling unit apartment housing caused by such sharply different perspectives and suggest improvement measures. First, standards to determine different defects and remuneration standards between the Ministry of Land, Infrastructure and Transport and the court were analyzed. Then, problems were derived through an analysis of defects in past court cases, and the differences in perspectives between construction companies and residents were identified based on defect data from various construction companies. To tackle these issues, a classification measure for establishing a defect database for multi-family homes was also proposed.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.103-114
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• 2022

The Internet of Things (IoT) is one of the fastest technologies that are used in various applications and fields. The concept of IoT will not only be limited to the fields of scientific and technical life but will also gradually spread to become an essential part of our daily life and routine. Before, IoT was a complex term unknown to many, but soon it will become something common. IoT is a natural and indispensable routine in which smart devices and sensors are connected wirelessly or wired over the Internet to exchange and process data. With all the benefits and advantages offered by the IoT, it does not face many security and privacy challenges because the current traditional security protocols are not suitable for IoT technologies. In this paper, we presented a comprehensive survey of the latest studies from 2018 to 2021 related to the security of the IoT and the use of machine learning (ML) and deep learning and their applications in addressing security and privacy in the IoT. A description was initially presented, followed by a comprehensive overview of the IoT and its applications and the basic important safety requirements of confidentiality, integrity, and availability and its application in the IoT. Then we reviewed the attacks and challenges facing the IoT. We also focused on ML and its applications in addressing the security problem on the IoT.

• Journal of Pharmacopuncture
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• v.25 no.4
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• pp.369-381
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• 2022

Objectives: Hyperlipidemia (HL) is a major cause of ischemic heart diseases. The size-limiting effect of ischemic preconditioning (IPC), a cardioprotective phenomenon, is reduced in HL, possibly because of the opening of the mitochondrial permeability transition pore (MPTP). The objective of this study is to see what effect pretreatment with Inula racemose Hook root extract (IrA) had on IPC-mediated cardioprotection on HL Wistar rat hearts. An isolated rat heart was mounted on the Langendorff heart array, and then ischemia reperfusion (I/R) and IPC cycles were performed. Atractyloside (Atr) is an MPTP opener. Methods: The animals were divided into ten groups, each consisting of six rats (n = 6), to investigate the modulation of I. racemosa Hook extract on cardioprotection by IPC in HL hearts: Sham control, I/R Control, IPC control, I/R + HL, I/R + IrA + HL, IPC + HL, IPC + NS + HL, IPC + IrA+ HL, IPC + Atr + oxidative stress, mitochondrial function, integrity, and hemodynamic parameters are evaluated for each group. Results: The present experimental data show that pretreatment with IrA reduced the LDH, CK-MB, size of myocardial infarction, content of cardiac collagen, and ventricular fibrillation in all groups of HL rat hearts. This pretreatment also reduced the oxidative stress and mitochondrial dysfunction. Inhibition of MPTP opening by Atr diminished the effect of IrA on IPC-mediated cardioprotection in HL rats. Conclusion: The study findings indicate that pretreatment with IrA e restores IPC-mediated cardioprotection in HL rats by inhibiting the MPTP opening.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.142-142
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• 2023

Humans inevitably and continuously produce wastewater in daily life worldwide. To decrease the degradation of river water bodies and aquatic ecosystem therein, humans have built systems at different scales to collect, drain, and treat household-produced wastewater. Particularly, municipal wastewater treatment plants (WWTPs) with centralized controls have played a key role in reducing loads of nutrients in domestic wastewater for the last few decades. Notwithstanding such contributions, impaired rivers regarding water quality and habitat integrity still exist at the whole river basin scale. It is highly attributable to the absence of dilution capacity of receiving streams and/or the accumulation of the pollutant loads along flow paths. To improve the perspective for individual WWTPs assessment, the first crucial step is to achieve systematic understanding on spatial distribution characteristics of all WWTPs together in a given river basin. By taking the initiative, our former study showed spatial hierarchical distributions of WWTPs in three large urbanized river basins in Germany. In this study, we uncover how municipal WWTPs in the contiguous United States are distributed along river networks in a give river basin. The extended spatial scope allows to deal with wide ranges in geomorphological attributes, hydro-climatic conditions, and socio-economic status. Furthermore, we identify the relation of the findings with multiple factors related to human activities, such as the spatial distribution of human settlements, the degree of economy development, and the fraction of communities served by WWTPs. Generalizable patterns found in this study are expected to contribute to establishing viable management plans for recent water-environmental challenges caused by WWTP-discharges to river water bodies.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.396-409
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• 2023

In the field of autonomous vehicles, where high accuracy and reliability are critical, various satellite navigation augmentation systems have been developed to improve system performance. These systems generate correction and integrity information based on measurements and navigation data collected from ground reference stations, enhancing user positioning accuracy. Thus, the performance of the system heavily relies on the deployment and spacing of reference stations. To construct an effective satellite navigation augmentation system, careful consideration must be given to the installation points of reference stations. This paper presents a user positioning performance modeling formula and proposes a method for selecting the installation points of new reference stations. The proposed method involves selecting a candidate group area that can optimize the user's positioning performance. By utilizing this method, the system's performance can be improved, ensuring high accuracy and reliability for autonomous vehicle applications.

• Mycobiology
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• v.50 no.5
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• pp.366-373
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• 2022

Regulation of proper gene expression is important for cellular and organismal survival, maintenance, and growth. Abnormal gene expression, even for a single critical gene, can thwart cellular integrity and normal physiology to cause diseases, aging, and death. Therefore, gene expression profiling serves as a powerful tool to understand the pathology of diseases and to cure them. In this study, the difference in gene expression in Flammulina velutipes was compared between the wild type (WT) mushroom and the mutant one with clogging phenomenon. Differentially expressed transcripts were screened to identify the candidate genes responsible for the mutant phenotype using the DNA microarray analysis. A total of 88 genes including 60 upregulated and 28 downregulated genes were validated using the real-time quantitative PCR analysis. In addition, proteomic differences between the WT and mutant mushroom were analyzed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). Interestingly, the genes identified by these genomic and proteomic analyses were involved in stress response, translation, and energy/sugar metabolism, including HSP70, elongation factor 2, and pyruvate kinase. Together, our data suggest that the aberrant expression of these genes attributes to the mutant clogging phenotype. We propose that these genes can be targeted to foster normal growth in F. velutipes.

• Journal of Korean Society for Quality Management
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• v.51 no.1
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• pp.67-78
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• 2023

Purpose: The purpose of this study is to investigate the COVID-19 pandemic-driven effect changes of quality factors on customer satisfaction in Korean Police Civil Affairs Service. Methods: This study fitted a regression model to the data collected by Korean National Police Agency from 2019 (before COVID-19 pandemic) to 2020 (during COVID-19 pandemic). In order to simultaneously estimate the effects of major seven quality factors on customer satisfaction for 'before the pandemic' and for 'during the pandemic', the regression model included not only customer satisfaction as the dependent variable, but also the fourteen independent variables consisting of the seven quality factors and their seven interaction terms. The interaction terms were defined by multiplying each quality factor by a dummy variable indicating either before or during the pandemic. Therefore, the coefficient estimates of the interaction terms indicate the changes of their corresponding quality factor effects on customer satisfaction between before and during the pandemic. The double bootstrap method was applied to test the significance of coefficient estimates. Results: Both before and during the pandemic, all quality factors had positive effects on customer satisfaction. However, these effects changed differently from before to during the pandemic: (increased) supportability, sincerity, and convenience; (decreased) integrity, professionalism, and fairness; (unchanged) promptness. Conclusion: This study found that the pandemic caused significant effect changes of quality factors on customer satisfaction in Korean Police Civil Affairs Service. This finding suggests the necessity of carefully monitoring such effect changes to effectively and efficiently improve customer satisfaction. This study also identified that from before to during the pandemic, supportability, sincerity, and convenience become more important and hence, need to be better managed.