• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.320-323
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• 2006

A fluid transient analysis on the Koreasat 1 & 2 pipeline system is conducted through numerical parametric studies in which unsteady friction results are compared with quasi-steady friction results and show relatively accurate prediction of the response curve with the unsteady friction. The code developed and used in this analysis has finished verification through comparing with the original Zielke model, the full and recursive convolution model and quasi-steady model as a reference. The unsteady friction is calculated by the recursive convolution Zielke model in which a complete evolution history of velocity field is no longer required so that it makes the fluid transient analysis on the complicated system possible. The results show that the application of quasi-steady friction to model cannot predict the entire response curve properly except the first peak amplitude but application of unsteady friction to model can predict reasonably he response curve, therefore it is to know the characteristics of the propulsion system.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.63-66
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• 2009

Lighting currents are one of major influences on the dynamic performance of ground electrodes. High lighting current intensity changes in the dynamic grounding performance due to ionization of the soil and very fast fronted pulses. The previous analysis has often been based on quasi-static approximation that is not applicable to very fast fronted pulses. To extend the analysis to fast fronted pulses in this paper, the full-wave analysis method based in the rigorous electromagnetic-field theory approach is used and the effects of the ionization of the soil me disregarded. Based on the simulation results, the empirical formulas applicable for slow and very fast fronted lightning current pulses me reviewed; therefore the validity of the theoretical approach is verified through comparison between the calculated and measured results.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.450-458
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• 2007

This paper presents the results of a statistical analysis and its research findings focusing on the learning aspect in the process of international joint ventures (IJVs). The contents of this paper is derived from a sample of 96 field cases based on a proposed conceptual model of effective learning for international construction joint ventures (ICJVs). The paper presents a brief review on the conceptual model with hypotheses and summarized the key results of statistical analysis including factor and multiple regression analysis for the testing of the validity of the proposed conceptual model and its associated research hypotheses. Among other research findings, the research confirms that ICJVs provides an excellent platform of in-action learning for construction organization and suggests that good outcomes in learning could be reaped by a company who has a clear learning intent from the beginning and subsequently take corresponding learning actions during the full process of the joint venture.

• 한국동물위생학회지
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• 제39권4호
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• pp.259-266
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• 2016

Porcine epidemic diarrhea virus (PEDV) causes an acute and lethal watery diarrhea in piglets that is great economic losses to the swine country worldwide. The spike (S) glycoprotein is an important determinant for PEDV biological properties. In the present study, we determined the full-length S gene sequences of five Chung-nam PEDV field isolates collected in 2016. The S gene was amplified by RT-PCR, purificated, sequenced, analyzed and then compared with published sequences of other PEDV strains. 5 field strains share 98.5%~99.9% homologies with each other at the nucleotide sequence level and 96.7%~99.9% homologies with each other at the amino acids sequence level. Most field strains have nucleotide insertions, deletions and mutation regions, and show lower homologies (93.1~93.8%) with classical and vaccine strains, however higher homologies (99.1%~99.5%) with US PEDV isolates in 2013. By phylogenetic tree analysis based on nucleotide sequence, five PEDV field isolates were clustered into Genogroup 2b but differ genetically from the vaccine strains (SM-98 and DR-13).

• 한국전자통신학회논문지
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• 제10권10호
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• pp.1145-1156
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• 2015

현재 농작물의 품질과 직결되는 병해충에 관하여 농작물 재배 현장에서 바로 사용할 수 있는 모바일 전용의 응용 시스템은 부족한 실정이다. 따라서 본 논문에서는 병해충 예찰 및 기본 정보에 관해서는 충실하나 즉각적인 진단 기능이 매우 부족하고 아울러 농작물 재배 현장에서 바로 사용할 수 있는 모바일 기반의 병해충 전용 시스템의 부재를 개선하기 위해서, u-Farm을 위한 모바일 기반의 농작물 재배 현장 중심형 스마트 병해충 정보검색 시스템을 설계 및 구현한다. 제안하는 시스템은 이미지의 전문 분석에 유용한 검색 라이브러리인 루씬(Lucene) 및 JSON 데이터 구조를 기반으로 농작물 재배 현장에서 병해충의 정보를 웹뿐만 아니라, 본인이 소유한 스마트 폰을 통해 실시간으로 직접 확인할 수 있는 장점이 있다. 또한, 시스템의 확장 및 재사용성을 높이기 위해 객체지향 모델링을 기반으로 설계하였으며, 농작물의 메타 정보뿐만 아니라, 메타 정보 기반의 텍스트 및 색상 등과 같은 이미지 특징 정보를 기반으로 검색이 가능하다. 본 시스템을 통해 u-Farm 실현뿐만 아니라 농업인이나 재배 현장 관리자들이 농작물 작황, 병해충 현황 파악 및 관리를 실시간으로 진행할 수 있다.

• Coupled systems mechanics
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• 제1권2호
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• pp.183-204
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• 2012

A method for the analysis of wave scattering in 3-D elastic full space is developed by means of the coupled boundary-volume integral equation, which takes into account the effects of both the boundary of inclusions and the uctuation of the wave field. The wavenumber domain formulation is used to construct the Krylov subspace by means of FFT. In order to achieve the wavenumber domain formulation, the boundary-volume integral equation is transformed into the volume integral equation. The formulation is also focused on this transform and its numerical implementation. Several numerical results clarify the accuracy and effectiveness of the present method for scattering analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.397-401
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• 1995

ESPI(Electronic Speckle Pattern Interfermetry) is an optical technique to measure surface deforamtion of engineering components and materials in industrial ares. This optical method is capable of providing full-field results with high spatial resolution, high speed and is the non-contact technique. One of important application aspects using electronic speckle pattern interferometry is to generate contours of a diffuse object in order to provide data for 3-D shape analysis and topography measurement. The contouring method by modified dual-beam speckle pattern interferometry is proposed. We introduce a shift of the illumination beams through optical fiber in order to obtain the contour fringe patterns. The speckle pattern correlation technique is suitable for providing measurement range from millimeters to several centimeters. The complete geometric analysis of the contoretical and experimental results are obtained.

• Wind and Structures
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• 제13권4호
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• pp.327-346
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• 2010

During the past decade, many electrical transmission tower structures have failed during downburst events. This study is a part of a research program aimed to understand the behaviour of transmission lines under such localized wind events. The present study focuses on the assessment of the dynamic behaviour of the line conductors under downburst loading. A non-linear numerical model, accounting for large deformations and the effect of pretension loading, is developed and used to predict the natural frequencies and mode shapes of conductors at various loading stages. A turbulence signal is extracted from a set of full-scale data. It is added to the mean component of the downburst wind field previously evaluated from a CFD analysis. Dynamic analysis is performed using various downburst configurations. The study reveals that the response is affected by the background component, while the resonant component turns to be negligible due large aerodynamic damping of the conductors.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.371-379
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• 2000

The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed model, we compare with the results of simplified 3D FEA, general 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.220-223
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• 2002

This paper introduces the development procedure of paddle type small-scaled composite rotor blade for helicopter hingeless rotor system. Paddle type composite blade design was done by using CORDAS program developed by KARI and dynamic analysis for hingeless hub with blade is done by using FLIGHTLAB which is commercial software for helicopter comprehensive analysis. The procedure to manufacture complicated shape of paddle type blade tip was developed and composite blades were manufactured after establishing the effective curing method. Through this research, the development technology of composite rotor blade with complex aerodynamic shape were accumulated and these will be applied to the related research field, for example, full size composite blade development, etc.