• Bulletin of the Korean Mathematical Society
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• v.56 no.4
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• pp.993-1006
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• 2019

This article concerns a ring property which preserves the reversibility of elements at nonzero idempotents. A ring R shall be said to be quasi-reversible if $0{\neq}ab{\in}I(R)$ for a, $b{\in}R$ implies $ba{\in}I(R)$, where I(R) is the set of all idempotents in R. We investigate the quasi-reversibility of 2 by 2 full and upper triangular matrix rings over various kinds of reversible rings, concluding that the quasi-reversibility is a proper generalization of the reversibility. It is shown that the quasi-reversibility does not pass to polynomial rings. The structure of Abelian rings is also observed in relation with reversibility and quasi-reversibility.

• Mass Spectrometry Letters
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• v.9 no.4
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• pp.110-114
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• 2018

Since accumulation of chemicals in deciduous teeth can occur from the second trimester of fetal development to shedding, a deciduous tooth has been considered as an attractive biomatrix for estimating individual chemical exposures recently. Therefore, detection of organic chemicals from teeth has received an increasing attention in exposomics research. Most previous studies on organic chemical analysis of teeth not only focused on a few targeted chemicals but also ignored potential contaminants from an enamel surface or a dental pulp. Recently, our group started developing a multi-class organic analysis method for deciduous teeth and tried to find a proper incubation condition of tooth materials. Our results showed that incubation with methanolic HCl provided the best performance among tested.

• Corrosion Science and Technology
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• v.18 no.2
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• pp.49-54
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• 2019

The purpose of this paper is to present failure analysis, of the heat exchanger tube in a district heating system. SS304 stainless steel is used, as material for the heat exchanger tube. The heat exchanger operates in a soft water environment containing a small amount of chloride ions, and regularly repeats operation and standstill period. This causes concentration of chloride ions on the outer surface of the tube, as well as repeat of thermal expansion, and shrinkage of the tube. As a result of microscopic examination, cracks showed transgranular as well as branched propagation, and many pits were present, at the initiation point of each crack. Energy disperstive spectroscopy analysis showed Fe and O peak, as well as Cl peak, meaning that cracks were affected by Cl ion. Failure of the tube was caused by chloride-induced stress corrosion cracking by thermal stress, high temperature, and localized enrichment of chloride ions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.160-162
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• 2019

음향 이벤트 인식 기술은 오디오 신호에서 음향 이벤트를 예측하는 기술로, 최근 대용량 데이터베이스의 배포, 인식 알고리즘과 하드웨어의 발전, 관련 인식 대회 등에 힘입어 많은 연구가 이루어지고 있는 분야이다. 본 논문에서는 음향 장면 및 이벤트 인식 관련 대회인 DCASE 챌린지에 대하여 기술하고, 약한 레이블 기반의 데이터를 학습해 강한 레이블을 예측하는 DCASE 챌린지 과제 4에 대하여 설명한다. 또한 DCASE 챌린지 과제 4에 제출된 다양한 음향 이벤트 인식 알고리즘과 데이터베이스의 종류에 따른 성능을 비교하여 음향 이벤트 인식 성능을 분석한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.267-270
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• 2019

Through this research, the rating data of shops were analyzed. The model was designed for discrete multiple classification as to the corresponding data, and the following experiments were initiated to observe the learned machine. By comparing each benchmarks in the experiments, which contains different setting variables for the machine model, the hit ratio was measured which indicates how much it is matched with the expected label. By analyzing those results from each benchmarks, the model was redesigned one time during the research and the effects of each setting variables on this machine were clarified. Furthermore, the research result left the future works, which are related with how the learning could be improved and what should be designed in the further research.

• Journal of the Korean Magnetic Resonance Society
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• v.23 no.3
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• pp.73-80
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• 2019

Nitrogen-vacancy (NV) is one of the most popular solid-state spin systems for quantum sensing. NV has been used for vector magnetometry with nanometer spatial resolution and sensors for nuclear magnetic resonance (NMR) in samples with small volume, less than 10 pL. Various studies are in progress to make NV a complementary sensor for current NMR technique. Fabricating and improving diamond itself are one of the research topics. This mini-review contains recent develops in diamond fabrication and treatment for higher NV yield. Additionally, we briefly introduce the development status of NV in NMR.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.50-58
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• 2019

The clear and specific objective of this study is to design a false news discriminator algorithm for news articles transmitted on a text-based basis and an architecture that builds it into a system (H/W configuration with Hadoop-based in-memory technology, Deep Learning S/W design for bigdata and SNS linkage). Based on learning data on actual news, the government will submit advanced "fake news" test data as a result and complete theoretical research based on it. The need for research proposed by this study is social cost paid by rumors (including malicious comments) and rumors (written false news) due to the flood of fake news, false reports, rumors and stabbings, among other social challenges. In addition, fake news can distort normal communication channels, undermine human mutual trust, and reduce social capital at the same time. The final purpose of the study is to upgrade the study to a topic that is difficult to distinguish between false and exaggerated, fake and hypocrisy, sincere and false, fraud and error, truth and false.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1639-1658
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• 2019

Named entity recognition (NER) is an important technique for improving the performance of data mining and big data analytics. In previous studies, NER systems have been employed to identify named-entities using statistical methods based on prior information or linguistic features; however, such methods are limited in that they are unable to recognize unregistered or unlearned objects. In this paper, a method is proposed to extract objects, such as technologies, theories, or person names, by analyzing the collocation relationship between certain words that simultaneously appear around specific words in the abstracts of academic journals. The method is executed as follows. First, the data is preprocessed using data cleaning and sentence detection to separate the text into single sentences. Then, part-of-speech (POS) tagging is applied to the individual sentences. After this, the appearance and collocation information of the other POS tags is analyzed, excluding the entity candidates, such as nouns. Finally, an entity recognition model is created based on analyzing and classifying the information in the sentences.

• Review of KIISC
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• v.31 no.5
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• pp.33-38
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• 2021

한국인터넷진흥원 종합분석팀은 사이버 위협 인텔리전스(CTI)를 통해 주요 침해사고를 추적하여 분석하고 이에 대한 대응방안을 마련, 공유하는 역할을 수행하고 있다. 구체적으로는 외부 협력채널 혹은 기존 사고에서 사용된 악성도구의 흔적을 기반으로 악성 인프라를 탐지하고, 이에 대한 공격자의 전략을 상세히 분석, 정리한 보고서를 발간하여 기업의 보안 수준을 제고하려 노력하고 있다. 본고에서는 사이버 위협 인텔리전스 측면에서 변화한 종합분석의 관점 및 역할을 소개하고, 고도화되어가는 침해사고를 대응하기 위한 향후 전략을 제안한다.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.120-126
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• 2021

The importance of mathematics is emerging to create new values and secure competitiveness in an intelligent information society based on the Fourth Industrial Revolution. This study was conducted with the aim of improving the academic performance and increasing interest of electronics majors in mathematics subjects. In order to develop learners' mathematical capabilities in major fields that utilize mathematics that electronics majors do not prefer, we have proposed a new teaching method to promote employment in mathematics-based electronics fields. In addition, to enhance learners' self-directed learning, we developed teaching methods for efficient mathematics subjects with programming languages as tools in electronics engineering and applied them to real-world teaching sites to effectively cultivate academic performance improvement of majors. Finally, we conducted a survey and statistically analyze the effectiveness of the developed teaching methods to present effective operational measures for mathematics education, an essential tool in intelligent information technology.