• 한국전기화학회:학술대회논문집
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• 2003.07a
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• pp.107-111
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• 2003

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.675-689
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• 2019

Development of smart construction materials with both self-strain and self-damage sensing capacities is still difficult because of little information about the self-damage sensing source. Herein, we investigate the effects of the matrix strength, fiber geometry, and fiber content on the electrical resistivity of steel-fiber-reinforced cement composites by multi-fiber pullout testing combined with electrical resistivity measurements. The results reveal that the electrical resistivity of steel-fiber-reinforced cement composites clearly decreased during fiber-matrix debonding. A higher fiber-matrix interfacial bonding generally leads to a higher reduction in the electrical resistivity of the composite during fiber debonding due to the change in high electrical resistivity phase at the fiber-matrix interface. Higher matrix strengths, brass-coated steel fibers, and deformed steel fibers generally produced higher interfacial bond strengths and, consequently, a greater reduction in electrical resistivity during fiber debonding.

• Journal of Software Assessment and Valuation
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• v.16 no.1
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• pp.89-94
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• 2020

In this paper, we propose a software algorithm that can configure n-key roll-over that detects all keys without limitation on the number of pressed keys in the dynamic scanning detection of a keyboard composed of a matrix. The proposed algorithm uses the timer interrupt of the microcontroller for computer keyboard control, so that a constant and accurate detection interval can be obtained, and an accurate debounce time can be provided. In order to confirm the effectiveness of the proposed algorithm, a microcontroller was connected to a toy keyboard constructed in the form of a clavier and experiments were conducted. As a result of the experiment, it was confirmed that detection of all keys was performed accurately regardless of the number of keys pressed.

• Convergence Security Journal
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• v.14 no.7
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• pp.45-51
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• 2014

The most important point in the QoS management system to ensure the quality of the IoT system design goal is quality measurement system and the quality evaluation system. This research study is a matrix model for the IoT based on key quality measures by diagnosis system structure and function. Developing for the quality metrics measured Internet of Things environment will provide the foundation for the Internet of Things quality measurement/analysis. IoT matrix system for quality evaluation is a method to describe the functional requirements and the quality requirements in a single unified table for quality estimation performed. Comprehensive functional requirements and quality requirements by assessing the association can improve the reliability and usability evaluation. When applying the proposed method IoT quality can be improved while reducing the QoS signaling, the processing, the basis for more efficient quality assurances as a whole.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.287-288
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• 2011

본 연구에서는 마이크로프로세서 및 스마트폰 기반의 초소형, 저전력 심전도 계측 시스템에 적용하기 위한 심박동 검출 및 매트릭스 추정 기법을 이용한 실시간 이상 심전도 판별 알고리즘을 구현하였다. MIT-BIH 표준 데이터베이스를 이용하여 실시간 심전도 분석 알고리즘의 성능 평가를 수행한 결과 이상 심전도가 포함되어 있는 7개 레코드에서 심박동 검출 성공률은 99.63%, 매트릭스 추정기법을 이용한 이상 심전도 검출은 92.46%로 우수한 성능을 나타내었다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.689-690
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• 2007

전력 텔레매트릭스 시스템은 전력계통의 사고에 신속하게 대처하고 계통설비의 합리적인 유지보수 및 운영을 통해 계통의 신뢰도를 높이고자 고안된 시스템이다. 이 시스템은 전력기반설비들에 다양한 센서 및 센서네트워크를 구성하여 전력설비를 통합적으로 감시하고 변전소 보호IED의 데이터들과 함께 전력계통의 유지보수 스케쥴링 및 설비건전성평가와 더불어 고장시에 신속한 고장복구를 위해 고장정보를 운영자에게 보여주는 구조를 가지고 있다. 본 논문에서는 이러한 전력 텔레매트릭스 시스템중에서 하부 센서및 센서네트워크의 데이터와 보호IED의 데이터를 중간처리하고 상위 시스템으로 전송하는 역할을 하는 진단IED의 개발에 관한 것이다.

• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.107-115
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• 1999

Microstructural variation and strengthening effects with lamination methods of alumina fiber-reinforced ${\gamma}$-LiAlO2 matrixes for Molten Carbonate Fuel Cell(MCFC) were studied. The porosities of all matrix laminated by hot-pressing of two green sheets under 1 kg/$\textrm{cm}^2$ at 45$^{\circ}C$ for 1 min and by double-casting which the second layer cast on the first green sheet dried for 3.5h were more than 50%. The strength of the Al2O3 fiber-reinforced matrix prepared by lamination was enhanced by 70% in comparison with the non-laminated matrix (115 gf/$\textrm{mm}^2$) and the strength-directionality due to fiber-orientation also could be removed. The strength of matrixes laminated by triple-casting was higher than that of the double-cast matrix, but triple-cast matrix showed the directionality with the casting direction, and furthermore its porosity was less than 50%. Although the strength of matrixes laminated by double-casting (195 gf/$\textrm{mm}^2$) is slightly less than that of matrixes laminated by hot-pressing (212 gf/$\textrm{mm}^2$), the double-casting method was evaluated to be more efficient laminating process in MCFC matrix processing.

• Composites Research
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• v.29 no.6
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• pp.328-335
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• 2016

The purpose of this study is to develop fiber reinforced cement matrix composite (ECC) produced with limestone powder in order to achieve high ductility of the composite, and to evaluate flexural performance of structural members made with ECC. Four kinds of mixture proportions were determined on the basis of the micromechanics and a steady state cracking theory considering the matrix fracture toughness and fiber-matrix interfacial characteristics. The mechanical properties of ECC, represented by strain-hardening behavior in uniaxial tension, were investigated. Also, strength property of the composite was experimentally evaluated. Two structural members made with ECC were produced and tested. Test results were compared with those of conventional concrete structural members. Increased limestone powder contents of ECC provides higher ductility of the composites while generally resulting in a lower strength property. ECC structural members exhibited higher flexural ductility, higher flexural load-carrying capacity and tighter crack width compared to conventional structural members.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.3
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• pp.218-227
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• 2000

In this paper, we present a new fuzzy information retrieval method based on thesaurus. In the proposed method th thesaurus is represented by a fuzzy linguistic matrix, where the elements in fuzzy linguistic matrix represent a qualitative linguistic values between terms. In the fuzzy linguistic matrix, there are three kinds of fuzzy relationships between terms, i.e., similar relation, hierarchical relation, and associative relation. The implicit fuzzy relationships between terms are inferred by the transitive closure of the fuzzy linguistic matrix based on fuzzy theory. And the proposed method has the capability to deal with a qualitative linguistic weights in a query and in indexing of information items to reflect qualitative measure of human based on vague and uncertain decisions rather than a quantitiative measure. Therefore the proposed method is more flexible than the ones presented in papers[1-3]. Moreover our method is more effectual of time than the ones presented in papers[1-3] because we use a fuzzy linguistic matrix and AON (Associate Ordinary Number) values in query evaluation process. As a result, the proposed method allows the users to perform fuzzy queries in a more flexible and more intelligent manner.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.53-60
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• 2018

In particular, the investigation of tendons in PSC Box Girder Bridge should be done in a systematic way. It is important to identify preventative maintenance activities that should be carried out in order to analyze the risk factors by type of representative tensions and to reduce risks in the long term. However, in the current maintenance system, various methodologies for investigating and repairing tensions have been studied, but it is difficult to investigate precisely tensions. Therefore, to apply the risk assessment for screening of tensions to the domestic PSC Box Bridge, we presented a risk matrix evaluation index that is consistent with the state assessment and maintenance system.