• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.507-520
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• 2005

The R-trees are usually used for an index of trajectories in moving-objects databases. However, they need to access a number of nodes to trace same trajectories because of considering only a spatial proximity. Overlaps and dead spaces should be minimized to enhance the performance of range queries in moving-objects indexes. Trajectories of moving-objects should be preserved to enhance the performance of the trajectory queries. In this paper, we propose the TP3DR-tree(Trajectory Preserved 3DR-tree) using clusters of trajectories for range and trajectory queries. The TP3DR-tree uses two split policies: one is a spatial splitting that splits the same trajectory by clustering and the other is a time splitting that increases space utilization. In addition, we use connecting information in non-leaf nodes to enhance the performance of combined-queries. Our experiments show that the new index outperforms the others in processing queries on various datasets.

• Journal of the Korean Mathematical Society
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• v.51 no.3
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• pp.495-507
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• 2014

Nielsen and Rege-Chhawchharia called a ring R right McCoy if given nonzero polynomials f(x), g(x) over R with f(x)g(x) = 0, there exists a nonzero element r ${\in}$ R with f(x)r = 0. Hong et al. called a ring R strongly right McCoy if given nonzero polynomials f(x), g(x) over R with f(x)g(x) = 0, f(x)r = 0 for some nonzero r in the right ideal of R generated by the coefficients of g(x). Subsequently, Kim et al. observed similar conditions on linear polynomials by finding nonzero r's in various kinds of one-sided ideals generated by coefficients. But almost all results obtained by Kim et al. are concerned with the case of products of linear polynomials. In this paper we examine the nonzero annihilators in the products of general polynomials.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.507-508
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• 2018

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5078-5087
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• 2014

The aim of this study was to examine the effect of self-esteem, life satisfaction and quality of life of older people's in an elderly school program. A cross-sectional descriptive study was conducted with a survey of 269 older people in 3 elderly schools at G city from November 29, 2013 to 18. The data was analyzed using a t-test, ANOVA, Pearson's correlation coefficients and multiple regression using the SPSS WIN 20.0 program. As a research finding, an analysis of the quality of life between of the self-esteem (r=-.338, p<.001) and life satisfaction (r=-.507, p<.001) revealed significant correlations. The life satisfaction was the significant factor influencing the quality of life (${\beta}$=-.512, p< .001) and this variable explained 25.1% of the quality of life. The findings of this study should be integrated into elderly health and care services in the community and older people in elderly school programs to improve the quality of life through the systematic developments of intervention programs for health care.

• Communications of the Korean Mathematical Society
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• v.31 no.3
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• pp.507-518
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• 2016

The aim of this paper is to prove some strong convergence theorems for the modified Ishikawa iteration process involving a pair of a generalized asymptotically nonexpansive single-valued mapping and a quasi-nonexpansive multi-valued mapping in the framework of $\mathbb{R}$-trees under the gate condition.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.507-508
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• 2007

IEC 61850은 변전소자동화시스템에 대한 국제 표준 규격이다. IEC 61850 파트 6은 통신관련 IED(Intelligent Electronic Device) 구성과 IED 파라미터, 통신 시스템 구성, 개폐소 구조 및 이들 간의 관계를 설명하는 파일 형식을 규정한다. 이 파일 형식의 주요 목적은 IED 능력 설명, 호환되는 방법으로 여러 제조사들의 IED 엔지니어링 도구와 시스템 엔지니어링 도구 간의 SA 시스템 설명을 교환하는 것이다. 본 논문에서는 XML을 이용한 IED Configurator TOOl 구현을 제시하였다.

• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.67-79
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• 1998

This paper is about the performance of alternative refrigerants for low temperature and transport refrigeration chillers. A breadboard refrigeration chiller was constructed with counterflow heat exchangers. R502, its transitional alternatives of R402A and R402B, and long-term alternatives of R404A and R507 were tested in an attempt to compare the performance of each refrigerant against R502. Measurements were conducted at two condensing temperatures of 43.3$^{\circ}C$ and 52.$0^{\circ}C$ and the evaporating temperature was varied over a range from -$25^{\circ}C$ to -5$^{\circ}C$. The evaporator superheat and condenser subcooling were maintained constant at about 5$^{\circ}C$ for all tests. Test results showed that all alternative fluids tested in this work can be used as 'drop-in fluids' to replace R502 without any major problem. It is also found that in the long run HFC alternatives are to be used due to their favorable environmental characteristics and better performance.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.507-520
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• 2016

The effect of ZnO on cellulose acetate in the removal of benzophenone-3 (BP-3) was investigated. The benzophenone-3 (BP-3) which is an endocrine disrupting chemical (EDC) was completely removed (100%) from the drinking water using Cellulose Acetate (CA) and zinc oxide (ZnO) composite membranes. The membranes were prepared by DIPS method and the filtration experiments were conducted by dead end filtration unit. The macrostructure of the membrane were studied by ATR-IR and XRD Spectra's. Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) were used to study the micro properties of the membranes. The laboratory experiments such as water uptake study and pure water flux performed to confirm the increasing hydrophilicity. The enhancing hydrophilicity was confirmed with respect to higher the concentration of nanoparticles. Evaluation of BP-3 removal was carried in different experimental conditions, such as, different Trans membrane pressure and different concentration of feed. The membrane with low pressure showed better performance by rejecting 100% of BP-3. However, 1 ppm, 3 ppm and 6 ppm of feed solution was used and among them 3 ppm of feed solution gives 100% rejection. The ZnO nanoparticales enhances the performance of CA membrane by showing maximum rejection.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.507-510
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• 2008

Effect of V addition on the precipitation behavior and strength of Fe-36Ni based high strength Invar alloy for power transmission wire was investigated. Fe-36Ni Invar alloy plates were fabricated using conventional ingot casting followed by hot rolling. High strength can be obtained through precipitation hardening and strain hardening by cold rolling. Simulation using FactSage$^{(R)}$ revealed that equilibrium phases which can be formed are two kinds of MC-type precipitates, $Mo_{2}C$ and $M_{23}C_6$ carbide. The latter stoichiometric carbide was expected to be formed at relatively lower temperature of $800^{\circ}C$.