• Earthquakes and Structures
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• 제17권6호
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• pp.635-647
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• 2019

Tests and theoretical studies for seismic responses of a transmission tower-line system under coupled horizontal and tilt (CHT) ground motion were conducted. The method of obtaining the tilt component from seismic motion was based on comparisons from the Fourier spectrum of uncorrected seismic waves. The collected data were then applied in testing and theoretical analysis. Taking an actual transmission tower-line system as the prototype, shaking table tests of the scale model of a single transmission tower and towers-line systems under horizontal, tilt, and CHT ground motions were carried out. Dynamic equations under CHT ground motion were also derived. The additional P-∆ effect caused by tilt motion was considered as an equivalent horizontal lateral force, and it was added into the equations as the excitation. Test results were compared with the theoretical analysis and indicated some useful conclusions. First, the shaking table test results are consistent with the theoretical analysis from improved dynamic equations and proved its correctness. Second, the tilt component of ground motion has great influence on the seismic response of the transmission tower-line system, and the additional P-∆effect caused by the foundation tilt, not only increases the seismic response of the transmission tower-line system, but also leads to a remarkable asymmetric displacement effect. Third, for the tower-line system, transmission lines under ground motion weaken the horizontal displacement and acceleration responses of transmission towers. This weakening effect of transmission lines to the main structure, however, will be decreased with consideration of tilt component.

• 한국전기전자재료학회논문지
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• 제23권7호
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• pp.560-565
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• 2010

This paper presents the design factor of an overhead transmission tower structure in order to reduce the tower weight. The behaviour of transmission tower structures are affected by the horizontal angle of the tower structure, the equivalent wind pressure group, the slope of the main post of the tower, the separation of the internode and the use of high-strength materials in their construction. Tower weight can be reduced by approximately 30% reduce weight by means of optimal design based on a consideration of all the above factors. In addition, the design of the foundation of the tower with the shear key installation to increase horizontal support together with a modified angle of inclination to the ground can reduce by about 37% the amount of concrete used during construction. The area of ground disturbed by the construction of the tower foundation can thus be reduced by approximately 33%. Therefore it is possible to build an environmently-friendly T/L tower with the mechanical properties of existing towers.

• 한국수산과학회지
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• 제48권4호
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• pp.403-410
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• 2015

Viral nervous necrosis (VNN) is a serious disease of sevenband grouper Epinephelus septemfasciatus in Korean aquaculture farms. However, we suggest the following preventative methods for hatcheries: 1) disinfecting rearing water, 2) selecting spawners via ELISA and PCR, 3) selecting eggs via PCR, 4) disinfecting fertilized eggs, and 5) proper facilities management. When these methods are implemented, nervous necrosis virus (NNV)-free fish are produced because vertical and horizontal transmission is prevented. However, horizontal transmission of NNV through rearing seawater sourced from the environment during grow-out stages in sea cages can still occur. Live NNV vaccines with a low rearing temperature or Poly(I:C) immunization are very effective at preventing horizontal transmission of NNV in rearing farms. Furthermore, even after VNN is contracted, fish mortality can be reduced by administering Poly(I:C).

• 한국전자파학회논문지
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• 제17권12호
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• pp.1231-1239
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• 2006

본 연구는 수동 루프 축소 시험 장치를 이용하여 수동 루프 유형별 자기장 저감 효과를 분석하였다. 본 연구에서는 수직 2회선 선로 및 수평 선로를 대상으로 실험을 통하여 향후 실증 시험 선로에 적용할 수동 루프의 자기장 저감 효과를 검토하였다. 그 결과 수동 루프 채용으로 선로 리액턴스 보상이 없어도 50 % 이상의 송전 선로의 자기장 저감 효과를 얻을 수 있음을 확인함으로써 실증 선로 수동 루프 적용 방안을 확보하였다. 대부분 우리나라 송전 선로에 채용되는 수직 2회선 선로에서는 수평 루프보다는 수직 루프가 자기장 저감율에 보다 효과적이었으며 차폐 영역에서도 근거리뿐만 아니라 원거리까지도 효과가 좋음을 알 수 있었다. 또한, 수동 루프를 3 턴으로 설치하는 경우가 1 턴에 비해 2배정도 자기장 저감 효과가 있음을 확인하였다.

• Ocean Systems Engineering
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• 제11권1호
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• pp.1-16
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• 2021

Experimental and numerical investigations were conducted to study the performance of a surface-fixed horizontal porous wave barrier in regular waves. The characteristics of the reflection and transmission coefficients, energy dissipation, and vertical wave force were examined versus different porosities of the barrier. Numerical simulations based on 3D Reynolds Averaged Navier-Stokes equations with standard low-Re k-ε turbulent closure and volume of fluid approach were accomplished and compared with the experimental results conducted in a 2D wave tank. Experimental measurements and numerical simulations were shown to be in satisfactory agreement. The qualitative wave behavior propagating over a horizontal porous barrier such as wave run-up, wave breaking, air entrapment, jet flow, and vortex generation was reproduced by CFD computation. Through the discrete harmonic decomposition of the vertical wave force on a wave barrier, the nonlinear characteristics were revealed quantitatively. It was concluded that the surface-fixed horizontal barrier is more effective in dissipating wave energy in the short wave period region and more energy conversion was observed from the first harmonic to higher harmonics with the increase of porosity. The present numerical approach will provide a predictive tool for an accurate and efficient design of the surface-fixed horizontal porous wave barrier.

• Journal of Veterinary Science
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• 제21권3호
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• pp.34.1-34.10
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• 2020

Background: A nationwide outbreak of foot-and-mouth disease (FMD) in South Korea caused massive economic losses in 2010. Since then, the Animal and Plant Quarantine Agency (QIA) has enhanced disinfection systems regarding livestock to prevent horizontal transmission of FMD and Avian influenza (AI). Although the amount of disinfectant used continues to increase, cases of FMD and AI have been occurring annually in Korea, except 2012 and 2013. Objectives: This study measured the concentration of the disinfectant to determine why it failed to remove the horizontal transmission despite increased disinfectant use. Methods: Surveys were conducted from February to May 2017, collecting 348 samples from disinfection systems. The samples were analyzed using the Standards of Animal Health Products analysis methods from QIA. Results: Twenty-three facilities used inappropriate or non-approved disinfectants. Nearly all sampled livestock farms and facilities-93.9%-did not properly adjust the disinfectant concentration. The percentage using low concentrations, or where no effective substance was detected, was 46.9%. Furthermore, 13 samples from the official disinfection station did not use effective disinfectant, and-among 72 samples from the disinfection station-88.89% were considered inappropriate concentration, according to the foot-and-mouth disease virus guidelines; considering the AIV guideline, 73.61% were inappropriate concentrations. Inappropriate concentration samples on automatic (90.00%) and semi-automatic (90.90%) disinfection systems showed no significant difference from manual methods (88.24%). Despite this study being conducted during the crisis level, most disinfectants were used inappropriately. Conclusions: This may partially explain why horizontal transmission of FMD and AI cannot be effectively prevented despite extensive disinfectant use.

• 대한전자공학회논문지SD
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• 제41권4호
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• pp.29-40
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• 2004

본 논문에서는 유한 차분 시간 영역(FDTD, Finite Differential Time Domain)법과 완전 정합층(PML, Perfectly Matched Layer) 방법을 이용하여 반도체 다층 배선이 평행하게 인접하거나, 교차하면서 인접하는 구조뿐 아니라. 평행하게 인접하면서 다른 평면상에 두 배선이 존재하는 3차원 다층 배선 구조에 대한 컴퓨터 수치 분석 방법을 보고한다. 평행한 인접 배선 구조에서는 수평 거리를 변화시키면서 출력 결과를 비교하였으며, 교차한 인접 배선 구조에서는 수직 거리를 변수로 하여 시간 영역과 주파수 영역에서의 출력 결과를 정량적으로 비교하였다. 또한, 평행하게 인접하면서 다른 평면상에 두 배선이 존재하는 3차원 다층 배선 구조에 대해서는 수평 거리와 수직 거리를 각각 변화시켜 가면서 출력되는 누화 특성을 측정하고 비교하였다.

• 조명전기설비학회논문지
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• 제30권3호
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• pp.53-58
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• 2016

The underground transmission lines which have been built to expand the suppling facilities will be continuously accompanying with high growth of the increase of power demand in the metropolitan area in recent years. So, it is necessary to maximize the ability and reliability of power supply with the current-carrying capability of the underground transmission lines. Design criteria of KEPCO is to be presented and used frequently. But it has to be studied about the installation methods of power cable buried in ground. In this study, we used the program for calculating the current-carrying capability of underground transmission power cables. We estimated the maximum permissible current values by the horizontal arrangement in the installation methods of power cable(154kV XLPE $600mm^2$) buried ducts in ground. To see the general tendency of the analysis, we researched a statistical analysis with such parameters as the maximum permissible current values. Through the regression analysis, we analyze the most highly values of the maximum permissible current on the Ra type duct arrangement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1357-1378
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• 2013

Energy constraint of wireless sensor networks makes energy saving and prolonging the network lifetime become the most important goals of routing protocols. In this paper, we propose an Energy Efficient Chain-based Routing Protocol (EECRP) for wireless sensor networks to minimize energy consumption and transmission delay. EECRP organizes sensor nodes into a set of horizontal chains and a vertical chain. Chain heads are elected based on the residual energy of nodes and distance from the header of upper level. In each horizontal chain, sensor nodes transmit their data to their own chain head based on chain routing mechanism. EECRP also adopts a chain-based data transmission mechanism for sending data packets from the chain heads to the base station. The simulation results show that EECRP outperforms LEACH, PEGASIS and ECCP in terms of network lifetime, energy consumption, number of data messages received at the base station, transmission delay and especially energy${\times}$delay metric.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.641-643
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• 2005

It is usual to operate the long transmission line with transposition of each phase in order to avoid voltage unbalance due to unbalanced capacitances at each phase of the line end. This paper described the Ferranti voltage rise of line end, charging current and secondary arc current according to the transposition of line or not. The positive and negative sequence current was derived by the phase current, and then the unbalanced rate was calculated. Then, we obtained the reclosing dead time of the single phase reclosing scheme for 500 kV single circuit horizontal arrangement transmission line system.