• Wind and Structures
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• 제34권2호
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• pp.231-257
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• 2022

Transmission lines systems are important components of the electrical power infrastructure. However, these systems are vulnerable to damage from high wind events such as hurricanes. This study presents the results from a 1:50 scale aeroelastic model of a multi-span transmission lines system subjected to simulated hurricane winds. The transmission lines system considered in this study consists of three lattice towers, four spans of conductors and two end-frames. The aeroelastic tests were conducted at the NSF NHERI Wall of Wind Experimental Facility (WOW EF) at the Florida International University (FIU). A horizontal distortion scaling technique was used in order to fit the entire model on the WOW turntable. The system was tested at various wind speeds ranging from 35 m/s to 78 m/s (equivalent full-scale speeds) for varying wind directions. A system identification (SID) technique was used to evaluate experimental-based along-wind aerodynamic damping coefficients and compare with their theoretical counterparts. Comparisons were done for two aeroelastic models: (i) a self-supported lattice tower, and (ii) a multi-span transmission lines system. A buffeting analysis was conducted to estimate the response of the conductors and compare it to measured experimental values. The responses of the single lattice tower and the multi-span transmission lines system were compared. The coupling effects seem to drastically change the aerodynamic damping of the system, compared to the single lattice tower case. The estimation of the drag forces on the conductors are in good agreement with their experimental counterparts. The incorporation of the change in turbulence intensity along the height of the towers appears to better estimate the response of the transmission tower, in comparison with previous methods which assumed constant turbulence intensity. Dynamic amplification factors and gust effect factors were computed, and comparisons were made with code specific values. The resonance contribution is shown to reach a maximum of 18% and 30% of the peak response of the stand-alone tower and entire system, respectively.

• 한국의류산업학회지
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• 제21권4호
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• pp.412-419
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• 2019

This study is to help maintain the identity of traditional Korean culture and develop fashion culture products by applying images and composition forms of traditional lattice patterns for vest designs. Lattice can be distinguished as a shape created through intersecting vertical and horizontal lines, in the form of oblique lines in vertical and horizontal structures, and in the form of an oblique line. Lattice patterns represent the overall unity and order as well as the beauty of small spaces created by simple lines. Traditional lattice patterns of the Joseon Dynasty were examined theoretically through the literature. Based on theoretical grounds, there is study illustrates vest designs using Adobe Illustrator CS6 as well as works on a 3D virtual costume using CLO Trial 4.2, a 3D virtual dressing system of CLO Virtual Fashion. This study developed an easy to wear vest design categorized as clothes for both men and women. The geometric formality of the lattice pattern has been applied to fashion culture products. In this study, the design was developed focusing on lattice, kotsal (flower pattern), sosulbitsal (diagonal), sotdaesal, tisal (horizontal & vertical). This study can be used as basic data in the domestic fashion cultural product market that can help maintain the originality of Korean culture in the global era that also assists in the successful promotion of Korean culture and traditions.

• 한국통신학회논문지
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• 제26권9B호
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• pp.1209-1214
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• 2001

본 논문에서는 양방향 디지털 가입자 회선 (Digital Subscriber Lines) 통신을 위해 격자 구조 (lattice structure)와 직교화된 IIR 형태의 필터가 결합된, 이른바 CALAOI(CAscade of LAttice and Orthogonalized IIR) 구조를 갖는 새로운 반향제거기를 제안한다. 모의실험을 통하여 CALAOI 반향제거기는 기존의 FIR 및 IIR 반향제거기보다 훨씬 적은 계산량 및 메모리, 그리고 빠른 수렴속도를 갖는 안정적인 반향제거기임을 확인할 수 있었다. CALAOI 반향 제거기는 xDSL뿐만 아니라, GIGA-bit Ethernet 등 고속 양방향 통신에서 서비스의 성능을 극대화하는데 크게 기여할 것으로 예상된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.64-69
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• 1997

The code WIMS-AECL has been used for the lattice analysis of DUPIC fuel. The lattice parameters calculated by the code is sensitive to the choice of number of parameters, such as the number of tracking lines, number of condensed groups, mesh spacing in the moderator region, other parameters vital to the calculation of probabilities and burnup analysis. We have studied this sensitivity with respect to these parameters and recommend their proper values which are necessary for carrying out the lattice analysis of DUPIC fuel.

• 조명전기설비학회논문지
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• 제26권2호
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• pp.51-60
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• 2012

An improved method for detecting fault distance in overhead transmission lines is described in this paper. Based on single-ended measurement, propagation theory of traveling waves together with the wavelet transform technique is used. In estimating fault location, a simple, but fundamental method using the time difference between the two consecutive peaks of transient signals is considered; however, a new method to enhance measurement sensitivity and its accuracy is sought. The algorithm is developed based on the lattice diagram for traveling waves. Representing both the ground mode and alpha mode of traveling waves, in a lattice diagram, several relationships to enhance recognition rate or estimation accuracy for fault location can be found. For various cases with fault types, fault locations, and fault inception angles, fault resistances are examined using the proposed algorithm on a typical transmission line configuration. As a result, it is shown that the proposed system can be used effectively to detect fault distance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.55-58
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• 1999

For the asymmetric digital subscriber line communications, the paper proposes a new echo canceller with the so-called CALAOI(CAscade of LAttice and Orthogonalized IIR) structure, which comprises of a lattice and an orthogonalized IIR structure. Through simulations, the CALAOI echo canceller was verified to have much fewer complexity of computations and has faster convergence speed than conventional FIR echo canceller. The CALAOI echo canceller is predicted to maximize performances of communication services in high speed communications such as VDSL, GIGA bit Ethernet, and so on as well as ADSL.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.10-17
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• 2011

Free energy based lattice Boltzmann method (LBM) has been used to simulate the contact angle and the bubble necking with large density ratio. LBM with the proper contact angle model is able to reduce the spurious currents and eliminate the singularity in the contact lines. The numerical results of the contact angles are satisfied with the Youngs law. For bubble necking flows, simulations are executed for various viscosities and contact angles. The phenomena of the bubble necking are simulated successfully and the subsequent results are presented. The present method is also applicable to the nucleate boiling flows.

• 융복합기술연구소 논문집
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• 제4권1호
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• pp.37-41
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• 2014

For the analysis of lifting surface at high angle of attack, a Nonlinear Vortex Lattice Method(NLVLM) was used. The NLVLM is intented to compute the interactions between lifting surfaces and separated vertical flow. The lifting surfaces are represented by a lattice of discrete vortex rings. And wakes are represented by families of non-lintersecting, semi-infinite vortex line segments. The image method also used to analyze the ground effect. It is found that vortex lines separated from lifting surfaces represent the separated flows successfully. Although the present method is applied for the rectangular wing and delta wing, extensions can be possible for the arbitrary lifting surfaces. The Present results show good agreement with experimental data.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3547-3552
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• 2013

Single crystal EPR and optical studies of a mixed ligand zinc(II) complex doped with VO(II) ion is carried out to establish the structural properties. The angular variation of vanadyl hyperfine lines indicates a single site, with spin Hamiltonian parameters as: $g_{xx}=1.985$, $g_{yy}=1.979$, $g_{zz}=1.943$; $A_{xx}=8.71$, $A_{yy}=6.41$ and $A_{zz}=17.80$ mT. By comparing the direction cosines of principal g and A values with the direction cosines of metalligand bonds, it has been confirmed that the vanadyl ion has entered the lattice interstitially. The exact interstitial position of VO(II) in host lattice has been calculated using the fractional coordinates of atoms in the host lattice out of many assumptions. The EPR and optical data have been confirmed to obtain various bonding parameters, from which the nature of the bonding in the complex is discussed. FT-IR confirms the formation of structure of host lattice.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.76-87
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• 2010

The structural phase transition of $Cs_2MnCl_4{\cdot}2H_2O$ single crystals was investigated by determining the $^{133}Cs$ spin-lattice relaxation time $T_1$. The number of resonance lines in the $^{133}Cs$ spectrum changes from seven to one near 375 K, which means that above 375 K the Cs sites are symmetric. Further, the $T_1$ of the $^{133}Cs$ nucleus undergoes a significant change near 375 K, which coincides with the change in the splitting of the $^{133}Cs$ resonance lines. The change in $T_1$ near $T_C$ is related to the loss of $H_2O$, and means that the forms of the octahedra of water molecules surrounding $Cs^+$ are disrupted.