• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제26권10호
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• pp.52-59
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• 2012

In this paper, The cast resin transformer's vibration is measured using noncontact raser vibrometer(LV110D). The vibration characteristics of transformer windings and core are analyzed for relation between vibration magnitude and cause. Using the analysis results, the technique is presented to diagnose cast resin transformer. which is able to diagnose transformer' deformation in winding and core geometry. The magnetostriction and electromagnetic force act on the core and windings, causing them to vibrate. The vibration from windings and core penetrates into transformer cast resin and reaches the outside walls. The fundamental frequency of the core and windings vibration signal is twice that of the power frequency(120Hz). The results show that the magnitude of core vibration is linear to driving voltage amplitude and magnitude of windings vibration is increased to loading current under the some level and then stabilized.

• Journal of the Korean Institute of Landscape Architecture
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• 제28권3호
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• pp.97-104
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• 2000

Studies on the principle of traditional moulding techniques of architecture or structure are very important in the point of the work could accomplish succession to modern design. As an attempt of these work, this study tried to examine traditional moulding techniques applied in planes of ancient architecture and structure closely. The major findings of this study are summarized as follows; It was verified that planes of ancient Korean architectures and structures analyzed in this study was moulded by its multiple partitions with the six or eight partitions of circumference as the fundamental form. The well unearthed in kyong-bok palace recently was moulded by a concentric circle assumed form of 4 circle which was extended with equal interval and divided into multiple of 8 partition of circumference. Chon-duk-jung in chang-duk palace also was moulded by a concentric circle assumed form of 3 circle extended with equal interval, but circle were divide by 6 partitions. It was also found that 6$^{\circ}$§8 partitions of circumference(or its multiple partition) was applied to not only above structures but also the moulding planes of ancient architecture, and as a results, figures revealed in architectures analyzed is classified into three classes. And, this study analyzed arrangements of two temples. As a results, it is discovered that the Grid used in moulding planes of each building fixed the arrangement of buildings. Therefore, moulding by equal partition of circumference decided the form of each building and the relation of element at the same time.

• Journal of Power Electronics
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• 제15권1호
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• pp.216-226
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• 2015

Grid synchronization is one of the key techniques for the grid-connected power converters used in distributed power generation systems. In order to achieve fast and accurate grid synchronization, a new phase locked loop (PLL) is proposed on the basis of the complex filter matrixes (CFM) orthogonal signal generator (OSG) crossing-decoupling method. By combining first-order complex filters with relation matrixes of positive and negative sequence voltage components, the OSG is designed to extract specific frequency orthogonal signals. Then, the OSG mathematical model is built in the frequency-domain and time-domain to analyze the spectral characteristics. Moreover, a crossing-decoupling method is suggested to decouple the fundamental voltage. From the eigenvalue analysis point of view, the stability and dynamic performance of the new PLL method is evaluated. Meanwhile, the digital implementation method is also provided. Finally, the effectiveness of the proposed method is verified by experiments under unbalanced and distorted grid voltage conditions.

• The Transactions of the Korean Institute of Power Electronics
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• 제12권4호
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• pp.346-353
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• 2007

This paper deals with filter design for utility-interactive voltage-sourced PWM inverters built by single-phase full-bridge topology By analyzing the relation between utility voltage and the ac output voltage of single-phase half-bridge inverters, the instantaneous voltage applied on the filter inductor is deduced qualitatively and quantitatively. Moreover, switching ripple current through the filter inductor is calculated from the filter inductor voltage. Based on the above mentioned analysis, filter design method is proposed by evaluating the percentage of the switching ripple current against the rated fundamental current. Proposed filter design method is verified by simulation and experiment.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 한국화재소방학회 2001년도 추계학술대회 논문집
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• pp.118-125
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• 2001

Most of the laws and standards relevant to technology in Korea bear a resemblance to those in Japan. Electricity was not introduced to Korea until Lighting ceremony in Kyong-Bok palace observed in 1887. Since Korea was annexed to Japan in 1910 and our public works were under Japan control we have applied Japanese laws and regulations made by Chosun government-general. Independently from Japan the power electricity accepted power plants of USA, codes of NESC, ASME / ANSI, NEMA. Our generation and distribution system takes American style while our consumer side takes Japanese style. As global trade system was transferred GATT into WTO, the harmonization of technological standards, certification construction testing in the trend of world. This paper is based on WTO / TBT agreement coming in effect after 12th, April, 1979. For Korea the distribution system has a strong resemblance to American system so that unconvertible because IEC 60364 originated from Europe while NEC originated from USA. This papers deals with the fundamental elements of electrical safety system with comparing IEC 60364 with NEC. This paper considers how engineers should apply NFPA 70(NEC) and IEC based on the comparison of NEC to IEC in relation to electrical installations.

• Journal of the Korean Mathematical Society
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• 제46권5호
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• pp.895-905
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• 2009

Let $B^{n+1}$ be the unit ball in the complex vector space $\mathbb{C}^{n+1}$ with the standard Hermitian metric. Let ${\Sigma}^n={\partial}B^{n+1}=S^{2n+1}$ be the boundary sphere with the induced CR structure. Let f : ${\Sigma}^n{\hookrightarrow}{\Sigma}^N$ be a local CR immersion. If N < 3n - 1, the asymptotic vectors of the CR second fundamental form of f at each point form a subspace of the CR(horizontal) tangent space of ${\Sigma}^n$ of codimension at most 1. We study the higher order derivatives of this relation, and we show that a linearly full local CR immersion f : ${\Sigma}^n{\hookrightarrow}{\Sigma}^N$, N $\leq$ 3n-2, can only occur when N = n, 2n, or 2n + 1. As a consequence, it gives an extension of the classification of the rational proper holomorphic maps from $B^{n+1}$ to $B^{2n+2}$ by Hamada to the classification of the rational proper holomorphic maps from $B^{n+1}$ to $B^{3n+1}$.

• Journal of Soil and Groundwater Environment
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• 제26권6호
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• pp.157-164
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• 2021

Smart agriculture requires sensing systems which are fundamental for precision agriculture. Adequate and appropriate water and nutrient supply not only improves crop productivity but also benefit to environment. However, there is no available soil sensor to continuously monitor nutrient status in soil. Electrical conductivity (EC) of soil is affected by ion contents in soil and can be used to evaluate nutrient contents in soil. Comparison of various commercial EC sensors showed similar water content and EC values at water content less than 20%. Soil EC values measured by sensors decreased with decreasing soil water content and linearly correlated with soil water content. EC values measured by soil sensor were highly correlated with water soluble nutrient contents such as Ca, K, Mg and N in soil indicating that the soil EC sensor can be used for monitoring changes in plant available nutrients in soil.

• Journal of Korean Clinical Health Science
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• 제9권2호
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• pp.1486-1492
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• 2021

Purpose: By investigating oral health knowledge and oral health behavior of orthodontic patients, we intend to identify factors that affect their satisfaction with orthodontic treatment and use them as fundamental data for improving the satisfaction of orthodontic patients. Methods: Busan from February 1st to March 31st, 2021. Dental disease in Gyeongsangnam-do. A self-contained survey was conducted on patients undergoing orthodontic treatment in the clinic. A total of 185 copies were analyzed. Using the lBM SPSS Statistics 21 program, multiple regression analysis was conducted by setting oral health knowledge and oral health behavior as independent variables to determine factors affecting remedial treatment satisfaction. Results: The satisfaction level of orthodontic treatment was 1.53 points higher than 'understanding the cost of orthodontic treatment' and 'smooth relationship with related staff while receiving orthodontic treatment' was low at 1.23. The average calibration satisfaction was 1.34. Factors affecting remedial treatment satisfaction were shown in the order of oral health behavior (p<0.000), educational experience (p<0.010), gender (p<0.015) and oral health knowledge (p<0.020). Conclusions: Through the above results, it is necessary to develop programs to improve oral health knowledge through customized individual oral health education by enhancing individual oral health behaviors of individuals.

• Journal of architectural history
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• 제30권6호
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• pp.59-70
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• 2021

Compared with other philosophers and writers who were engaged in architecture Georges Bataille was extraordinary. Because he produced anti-architectural discourse. This paper studied the Bataille's thinking with relation to architecture that used as a fundamental and privileged metaphor. Philosophy regarded as the foundation of all academic discipline needed architecture in order to show its system was durable, synthetic and hierarchical. The will to build a solid system of reasoning made philosophy to call architecture to pretend that it is structurally stable. Metaphor and representation is inevitable in philosophy. Then architectural image that supported by discourse of philosophy became a representation of sociocultural system. According to Bataille architectural representation justified existing power and belief system. With architecture Identity always represented the true and good. This kind of architectonic thinking erased the Other that allowed metaphysics and symbolic Against architecture Bataille produced writings of violation and excess corresponding to labyrinth. Labyrinth in fact made a formal structure of architecture possible to be a metaphor of symbolic system. Bataille's anti-architectural thinking paradoxically shows the importance of Architecture and give a chance to rethink the ethical aspect of architecture instead of aesthetics.

• Korean Linguistics
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• 제79권
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• pp.145-169
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• 2018

The purpose of this paper is to review critically the validity and relevance of the pan-national language culture improvement movement, Annyeong! Urimal(Hello! Our Language) implemented for the last three years as part of the government-driven projects, and to seek for improvement direction or fundamental reorientation of this movement. In order to accomplish this purpose, this paper firstly points out abstract and conventional aspects of the diagnosis for background and the purpose of projects, and suggests that this movement focuses on verbal abuse rather than language destruction and pays attention to positive aspects of newly rising language use. Then, with reference to main agent, this paper argues that the government must lead actively formation of voluntary nongovernmental agent with indirect financial and institutional support. Thirdly, it is suggested that public language should be the top priority target sphere and the language used by the leaders of society and the older generation should be also included in the target spheres of this movement. Finally, this paper indicates that enlightenment/public relation projects end often in one time events, imposing unilaterally the normative contents, and also emphasizes the importance of survey/research projects and deliberation/evaluation projects.