• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.498-503
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• 2019

Electric propulsion ships are gaining widespread interest in the marine industry owing to extreme air pollution concerns. Consequently, several studies are actively being conducted for improving the power quality. Various methods have been developed that incorporate passive filters, notch filters, and active filters for reducing the harmonic content in the input current of a conventional diode front end rectifier. Among such filters, the active front end (AFE) rectifier is considered as an excellent technology. In this paper, current control for an AFE rectifier employing space vector PWM (Pulse Width Modulation) is proposed. Conventional current control methods for the AFE rectifier, hysteresis, SPWM (Sinusoidal Pulse Width Modulation), and SVPWM (Space Vector Pulse Width Modulation) were simulated by employing the PSIM software tool for analysis and comparisons. The results corroborate that SVPWM has the simplest structure and provides the best performance.

• Journal of The Korean Association of Information Education
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• v.23 no.4
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• pp.375-384
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• 2019

In a rapidly changing society with the Fourth Industrial Revolution, future students should have the skills to utilize and organize high-quality knowledge, not the amount of knowledge. With the launch of the revised curriculum in 2015, the curriculum has been reorganized based on competency and the software education has been seeking capabilities such as 'Cultural computing knowledge', 'Computational thinking', and 'Collaborative problem solving skills'. Therefore, practical collaboration tools and education programs that can be used in the field of education are developed based on Pair Programming, which is a specific collaborative learning strategy to develop cooperative problem solving skill. The educational program using this collaboration tool was developed with a focus on developing computational thinking and collaborative problem solving skills through Pair Programming rather than focusing on learning grammar of programming language and programming techniques. In a educational program, students will be able to use collaborative tools for pair programming and foster collaborative problem-solving skills.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.269-277
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• 2019

Since 2020, according to the International Convention for the Prevention of Pollution from Ships (MARPOL) amended in 2016, each Administration shall transfer the annual fuel consumption of its registered ships of 5,000 gross tonnage and above to the International Maritime Organization (IMO) after verifying them. The Administration needs stacks of materials, which must not be manipulated by ship companies, including the Engine log book and also bears an administrative burden to verify them by May every year. This study considers using the Automatic Identification System (AIS), mandatory navigational equipment, as an objective and efficient tool among several verification methods. Calculating fuel consumption using a ship's speed in AIS information based on the theory of a relationship between ship speed and fuel consumption was reported in several examples of relevant literature. After pre-filtering by excluding AIS records which had speed errors from the raw data of five domestic cargo vessels, fuel consumptions calculated using Excel software were compared to actual bunker consumptions presented by ship companies. The former consumptions ranged from 96 to 123 percent of the actual bunker consumptions. The difference between two consumptions could be narrowed to within 20 percent if the fuel consumptions for boilers were deducted from the actual bunker consumption. Although further study should be carried out for more accurate calculation methods depending on the burning efficiency of the engine, the propulsion efficiency of the ship, displacement and sea conditions, this method of calculating annual fuel consumption according to the difference between two consumptions is considered to be one of the most useful tools to verify bunker consumption.

• Herbal Formula Science
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• v.27 no.1
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• pp.45-52
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• 2019

Objectives : Hyperthermia is a widely used therapeutic tool for cancer therapy and a well-known inducer of apoptosis. Although the Cinnamomi cortex (CC) is a potent anticancer agent for several human carcinomas, it is less potent in the human U937 cell line. To explore any enhancing effects of CC with hyperthermia induced apoptosis, this study investigated the combined effects and apoptotic mechanisms of hyperthermia and CC in U937 cells. Methods : U937 cells were heat treated at $43^{\circ}C$ for 30 min with or without pre-treatment for 1h with CC and then incubated at $37^{\circ}C$ with 5% $CO_2$. Cell viability was analyzed by MTT assay and Trypan blue assay. Morphological changes reflecting apoptosis were visualized under microscope. Synergy effect of CC combined with hyperthermia were calculated by Compusyn software. The expression of proteins related to apoptosis and signaling pathways was determined by western blotting. Results : Hyperthermia with CC reduced cell viability and induced apoptosis. Combined hyperthermia and CC treatment markedly augmented apoptosis by upregulating proapoptotic proteins and suppressing antiapoptotic proteins, culminating in caspase-3 activation. Furthermore, the combined treatment, decreased the expression of in Bcl-2 family, cyclin D1, VEGF, MMP2 and MMP9 expression. Conclusion : This study provides compelling evidence that hyperthermia, in combination with CC, is a promising therapeutic strategy for enhancement of apoptosis and suggests a promising therapeutic approach for cancer.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.221-230
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• 2019

In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.190-192
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• 2019

Not only learners majoring in computer science, but also non-engineered learners want to implement their ideas as apps through real-life problems. In response, first-year university students with little experience in creating apps studied how to develop mobile platform apps to improve computing thinking skills. We applied the teaching and learning procedures of the Discovery-Design-Development among the software teaching and learning models, and used Android Studio Unified Development Environment (IDE) as a development tool to design mobile platform app development projects and assess whether they helped improve computing thinking skills. The application of the designed teaching and learning method found that the project output was implemented as an app through emulator, which gave students high interest in class and satisfaction, and was effective in improving their computing thinking ability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.166-171
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• 2020

Big data processing technology that can store and analyze data and obtain new knowledge has been adjusted for importance in many fields of the society. Big data is emerging as an important problem in the field of information and communication technology, but the mind of continuous technology is rising. the R, a tool that can analyze big data, is a language and environment that enables information analysis of statistical bases. In this paper, we use this to analyze the Bible data. We analyze the four Gospels of the New Testament in the Bible. We collect the Bible data and perform filtering for analysis. The R is used to investigate the frequency of what text is distributed and analyze the Bible through social network analysis, in which words from a sentence are paired and analyzed between words for accurate data analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.4
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• pp.558-564
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• 2021

With the recent introduction of 5G, electromagnetic radiation sources are spreading throughout life, so it is necessary to establish a citizen-centered electromagnetic safety management system. In particular, the beamforming method of the 5G antenna increases the power density measurement of electromagnetic waves by more than 10 times when the wireless base station is installed, so it is unreasonable to determine the safety by physical measurement. Therefore, it is necessary to determine the presence or absence of electromagnetic wave safety in daily life through a predictive method by calculation through systematic model analysis. In this paper, in order to check the possibility of a 5G wireless base station using an electromagnetic wave numerical analysis tool as a way to solve this problem, we compared the measured values of the actual base stations and the predicted values through the prediction model to compare the reliability. A method of constructing a real-time base station electromagnetic wave strength prediction evaluation system combined with software was also proposed.

• Entomological Research
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• v.48 no.5
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• pp.390-399
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• 2018

In order to precisely assess gene expression levels, the suitable internal reference genes must be served to quantify real-time reverse transcription polymerase chain reaction (RT-qPCR) data. For armyworm, Mythimna separata, which reference genes are suitable for assessing the level of transcriptional expression of target genes have yet to be explored. In this study, eight common reference genes, including ${\beta}$-actin (${\beta}$-ACT), 18 s ribosomal (18S), 28S ribosomal (28S), glyceraldehyde-3-phosphate (GAPDH), elongation fator-alpha ($EF1{\alpha}$), TATA box binding protein (TBP), ribosomal protein L7 (RPL7), and alpha-tubulin (${\alpha}$-TUB) that in different developmental stages, tissues and insecticide treatments of M. separata were evaluated. To further explore whether these genes were suitable to serve as endogenous controls, three software-based approaches (geNorm, BestKeeper, and NormFinder), the delta Ct method, and one web-based comprehensive tool (RefFinder) were employed to analyze and rank the tested genes. The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated according to normalized HSP70, and MsepCYP321A10 gene expression data. We found that the most suitable reference genes for the different experimental conditions. For developmental stages, 28S/RPL7 were the optimal reference genes, both $RPL7/EF1{\alpha}$ were suitable for experiments of different tissues, whereas for insecticide treatments, $28S/{\alpha}-TUB$ were suitable for normalizations of expression data. In addition, $28S/{\alpha}-TUB$ were the suitable reference genes because they have the most stable expression among different developmental stages, tissues and insecticide treatments. Our work is the first report on reference gene selection in M. separata, and might serve as a precedent for future gene expression studies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.97-110
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• 2004

As modem web services become enormously complex, web attacks has become frequent and serious. Existing security solutions such as firewalls or signature-based intrusion detection systems are generally inadequate in securing web services, and analysis of raw web log data is simply impractical for most organizations. Visual display of "interpreted" web logs, with emphasis on anomalous web requests, is essential for an organization to efficiently track web usage patterns and detect possible web attacks. In this paper, we discuss various issues related to effective real-time visualization of web usage patterns and anomalies. We implemented a software tool named SAD (session anomaly detection) Viewer to satisfy such need and conducted an empirical study in which anomalous web traffics such as Misuse attacks, DoS attacks, Code-Red worms and Whisker scans were injected. Our study confirms that SAD Viewer is useful in assisting web security engineers to monitor web usage patterns in general and anomalous web sessions in particular.articular.