• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.321-327
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• 2018

DC microgrid system composed of multiple converters has a tendency to make the system unstable due to the interaction of converters. To solve this problem, in this paper, the interaction between cascaded converters with LC input filter is analyzed with impedance modeling using g-parameter. The input impedance and the output impedance of the system can be obtained through this technique. The stability of the system can be determined by applying Middlebrook's stability criterion to the impedance. Virtual impedance is added to the controller to enhance stability. The validity of the analysis is verified by the result of several simulations and experiments.

• Mycobiology
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• v.39 no.4
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• pp.321-323
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• 2011

Severe violet root rot occurred in a field of membranous milk vetch in Bonghwa, Korea, in October 2010. Two fungal isolates from the diseased plants were identified as Helicobasidium mompa based on their morphological, cultural, and molecular characteristics. This is the first report that H. mompa causes violet root rot on membranous milk vetch in Korea.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.321-323
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• 2016

최근 SNS, 클라우드 서비스, IoT 등 신기술이 발전함에 따라서 개인 정보 보호와 보안에 관심이 대두 되었다. 때문에 기업들은 고객 정보 보호를 위한 보안 솔루션 구축이 필수불가결해졌다. 이러한 기업의 니즈를 충족시키기 위해 ESM이라는 보안 관리 시스템이 등장하고 최근에는 SIEM으로 넘어가고 있는 추세이다. SIEM은 관리자가 로그들을 모니터링 하는 방식으로 많은 양의 로그가 발생하거나 축적된 로그들을 분석하는 것은 한계가 있다. 따라서 본 논문에서는 빅 데이터 시스템을 이용하여 로그들을 축적하고 머하웃을 이용하여 축적된 로그들을 분석하는 자동화 시스템을 제안한다.

• Smart Structures and Systems
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• v.21 no.3
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• pp.321-333
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• 2018

Simplified Dolphin Echolocation (SDE) algorithm is a recently developed meta-heuristic algorithm. This algorithm is an improved and simplified version of the Dolphin Echolocation Optimization (DEO) method, based on the baiting behavior of the dolphins. The main advantage of the SDE algorithm is that it needs no empirical parameter. In this paper, the SDE algorithm is applied for optimization of three well-studied frame structures. The designs are then compared with those of other meta-heuristic methods from the literature. Numerical results show the efficiency of the SDE algorithm and its competitive ability with other well-established meta-heuristics methods.

• Tribology and Lubricants
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• v.17 no.4
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• pp.321-334
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• 2001

The influence of aerated oil on high-speed journal bearing Is examined by thermohydrodynamic lubrication theory to lubrication with mixtures of a Newtonian liquid and an ideal gas. For this purpose, analytical models for viscosity and density of aerated oil in fluid-film bearing are applied. Convection to the walls, mixing with supply oil and re-circulating oil, and some degree of journal misalignment are considered. The results show that deliberate oil aeration can increase the load capacity of high-speed plain Journal bearing. And the load capacity is increased more by oil aeration under the conditions of shaft misalignment and higher speed.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.321-323
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• 2012

최근 모바일 기기 보급의 확산과 관련 기술의 발전으로 인해 사용자의 편의를 제공하는 다양한 서비스들이 제공되고 있다. 이러한 서비스 중에서 대표적인 것으로 사용자의 이동 경로를 파악하고 예측하여 알맞은 위치기반서비스(Location-based Service; LBS)를 제공하는 것이다. 위치기반서비스를 제공하기 위한 가장 핵심 기술은 사용자의 이동 경로를 파악하는 것인데, 기존의 이동 경로 파악 기술은 이전의 이동 경로 자료를 기반으로 현재 이동 경로를 유추하였다. 그러나 이전의 이동 경로 자료가 점점 증가함에 따라 방대한 자료를 보관하고 가공하는데 많은 비용이 발생하는 문제점이 있다. 본 논문에서는 이동 경로를 예측하기 위한 방법으로 사용자가 일정 지점에 머무는 시간 정보, 이동 거리 그리고 다른 사용자와의 소통 정보를 활용한다. 이 정보들을 활용하여 사용자에게 의미 있는 장소를 추출하고 이를 기반으로 사용자의 이동 경로를 예측할 때, 기존 방법과 비교하여 적은 비용으로 효과적인 경로 예측을 할 수 있다.

• Earthquakes and Structures
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• v.16 no.3
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• pp.321-327
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• 2019

This study investigated the possibility of using the recorded micro tremor data on ground level as ambient vibration input excitation data for investigation and application Operational Modal Analysis (OMA) on the bench-scale earthquake simulator (The Quanser Shake Table) for model chimney. As known OMA methods (such as EFDD, SSI and so on) are supposed to deal with the ambient responses. For this purpose, analytical and experimental modal analysis of a model chimney for dynamic characteristics was performed. 3D Finite element model of the chimney was evaluated based on the design drawing. Ambient excitation was provided by shake table from the recorded micro tremor ambient vibration data on ground level. Enhanced Frequency Domain Decomposition is used for the output only modal identification. From this study, best correlation is found between mode shapes. Natural frequencies and analytical frequencies in average (only) 1.996% are different.

• Wind and Structures
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• v.32 no.4
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• pp.321-340
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• 2021

In 2019, 5.6% of the total energy produced worldwide came from wind. Offshore wind generation is still a small portion of the total wind generation, yet its growth is exponential. Higher availability of sites, larger producibility and potentially lower environmental impacts make offshore wind generation attractive. On the other hand, as the water depth increases, fixed foundations are no more viable, and the new frontier is that of floating foundations. This paper brings an overview of why and how offshore wind energy should move deep water; it contains material from the Keynote Lecture given by the first author at the ACEM20/Structures20 Conference, held in Seoul in August 2020. The paper is organized into four sections: the first giving general concepts about wind generation especially offshore, the second and the third considering economic and technical aspects, respectively, of offshore deep-water wind generation, in the fourth, some challenges of floating offshore wind generation are presented and some conclusions are drawn.

• The Korean Journal of Food And Nutrition
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• v.36 no.4
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• pp.321-326
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• 2023

Noodles were manufactured using chickpea powder to evaluate quality characteristics. Compared to noodles made of wheat flour, noodles made with chickpea powder showed higher contents of protein, lipids, ash, and dietary fiber. Among noodle cooking characteristics, weight, moisture absorption rates, volume, and turbidity decreased significantly as the added amount of chickpea powder increased. Comparisons made of the color of noodles with raw noodles after cooking showed that the brightness (L value) of raw noodles tended to decrease as more chickpea powder was added after cooking, and levels of red (a value) and levels of yellow (b value) tended to increase as more chickpea powder was added after cooking. The texture of noodles with added chickpea powder tended to increase as more chickpea powder was added, such as hardness, springiness, gumminess, cohesiveness, and chewiness.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.321-322
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• 2009

본 논문에서는 문서분류를 위하여 SVD(Singular Value Decomposition)을 이용한 효율적인 특징 선택 방법을 제안한다. 분류기 알고리즘은 문서를 효과적으로 분류할 수 있지만 분류기에 입력되는 특징공간이 너무 크다는 단점이 있다. SVD를 이용하면 입력 데이터의 차원을 줄여줄 수 있으며 문서와 문서 사이의 관계성을 내포하는 벡터공간을 만들 수 있다. 따라서 SVD를 이용하면 문서분류의 시간과 효율을 동시에 증가시킬 수 있다. 본 논문에서는 실험을 통하여 SVD을 이용한 문서분류 시스템이 입력데이터에 대한 차원을 감소시키면서 훌륭한 분류 결과를 얻을 수 있음을 보여준다.