• Wind and Structures
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• 제31권6호
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• pp.509-522
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• 2020

Wind load is the principal cause for a large number of the collapse of transmission lines around the world. The transmission line is traditionally designed for wind load according to a linear equivalent method, in which dynamic effects of wind are not appropriately included. Therefore, in the present study, incremental dynamic analysis is utilized to investigate the stability behavior of a 400 kV transmission line under wind load. In that case, the effects of vibration of cables and aerodynamic damping of cables were considered on the stability behavior of the transmission line. Superposition of the harmonic waves method was used to calculate the wind load. The corresponding wind speed to the beginning of the transmission line collapse was determined by incremental dynamic analysis. Also, the effect of the yawed wind was studied to determine the critical attack angle by the incremental dynamic method. The results show the collapse mechanisms of the transmission line and the maximum supportable wind speed, which is predicted 6m/s less than the design wind speed of the studied transmission line. Based on the numerical modeling results, a retrofitting method has been proposed to prevent failure of the tower members under design wind speed.

• 한국전자통신학회논문지
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• 제14권2호
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• pp.289-296
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• 2019

최근 스마트폰 카메라 기술의 발달로 고화질의 동영상을 촬영할 수 있다. 이러한 기술을 다양한 방법으로 활용하기 위해 디스플레이 등의 외부 장치로 신호 전송이 가능하여야 한다. 영상신호의 전송 성능은 전송선로의 손실과 배선의 길이에 따라 결정된다. 논문에서는 스마트폰 디자인에 따라 변경되는 배선 길이와 인쇄회로기판 도체 배선 소재 표면 거칠기 진폭에 따른 HDMI 전송선로 설계 기준을 제안하였다. 또한 실제 스마트폰 설계에 제안된 설계 기준을 적용하여 검증하였다. 본 논문을 통해 제안된 설계 기준은 모바일 어플리케이션외 고속신호 전송선로가 포함되는 다양한 응용분야에 확대 적용될 수 있을 것으로 판단된다.

• 한국강구조학회 논문집
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• 제22권5호
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• pp.435-443
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• 2010

현행 송전강관철탑의 경우 허용응력 설계개념을 도입한 철탑설계기준을 적용하여 설계, 제작되고 있다. 이 철탑설계기준의 압축재의 설계 강도 결정은 압축재의 허용좌굴응력에 의하여 결정되고 있으나 이는 접합부의 내력을 고려치 않은 값이다. 부재가 압축좌굴내력에 도달하기 전에 접합부의 변형으로 인하여 국부변형에 의한 접합부 파괴가 발생할 수 있다. 따라서 본 연구에서는 접합부의 보강형태별로 접합부내력을 산출하고 이를 데이터베이스화한 후 지난 연구에서 도출한 등가비선형해석기법의 부재내력과의 상호 비교를 통하여 부재파괴와 접합부파괴의 선행 여부를 판별할 수 있는 실용적인 평가 및 설계 기법을 제시하였다.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.97-98
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• 2006

This study deals with the Transmission Error of gear tooth profile by modifying a Profile and lead of a surface of Tooth. First, we experimentally confirmed that the Transmission Error is a synthesis of the sliding Velocity between both gears. Since various types of Transmission errors appear in the experiments, we introduced definition of Transmission Error and The Optimism Design by modifying a surface parameters The test stand's performance is then evaluated through a series of multiple torque transmission error tests. Comparisons are made between data recorded before and after the test stand's redesign, and subsequently repeatability studies are performed to verify the veracity of the measured data. Finally, the experimental results are compared to the analytical predictions of two different gear analysis programs.

• ETRI Journal
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• 제33권6호
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• pp.985-988
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• 2011

A novel application of a dual-transmission line is proposed to design a lowpass filter (LPF). The proposed structure uses only transmission line elements to produce an equiripple LPF response with sharp roll-off. Design equations are derived using a lossless transmission line model. Controlling the electrical lengths, three transmission-zeros are realized in the stopband to obtain a sharp roll-off rate and wide stopband bandwidth. A single unit microstrip LPF with a 3-dB cut-off frequency at 1.0 GHz having a roll-off of 135 dB/GHz along with a stopband bandwidth of 69.5% is designed for validation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.551-554
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• 2008

In the recent year, Unmanned helicopters of airline industries are using in various industries such as monitoring system, agriculture and forest fire. A unmanned helicopter is needed a powerful engine for transport weighty payload and have to need a light weight. Therefore it is necessary a light weight transmission of the unmanned helicopter. Initially a rectangular transmission housing has been considered, but an empty space in the housing is not useful for light weight design. In this study, new model has been introduced into the transmission housing by using rapid prototyping. As a result, the weight of new transmission housing can be reduced very much as 67%.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.82.2-82
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• 2001

In this paper, when we design and implement an internet-based teleoperation control, some important points that should be considered (e.g., transmission characteristics, time delay prediction and transmission protocol are inspected and simulated. First, we will investigate data transmission characteristics at the Internet, and build a model for the transmission delay and packet loss through the characteristics of that effect. And then, we inspect how to predict transmission delay, and examine transmission protocols which are proper for the control-oriented Internet protocol. Finally, we apply it to a force-reflective teleoperation control system that consists of a six d.o.f haptic interface and a five d.o.f manipulator via the Internet.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.351-353
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• 2002

Up to now the design standard of tower for overhead transmission line in KEPCO was revised four times since 1970. During last year. we had reviewed this design standard. This paper shows the design standard of tower for overhead transmission line in KEPCO. In this standard, a kind of tower was defined as standard tower and special tower. Also we had defined usage range of standard tower, tower height, arrangement of power line, design condition of tower arm and etc. On the wind pressure, we had defined basic velocity pressure per region and maximum wind pressure. For special region, design wind pressure will be considered the receded wind velocity of meteorological observatory and regional condition by this standard.

• 오토저널
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• 제14권1호
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• pp.38-46
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• 1992

An optimal design technique for minimum power loss in Kopp Ball Variator Continuously Variable Transmission is developed. Kinematic analysis of traction drive contact is performed to find spin for Kopp Ball Variator, and traction force and torque are calculated from mathem atical model of traction drive contact. The objective function for optimal design is total power loss including contact loss and bearing losses. The design contraints are derived from energy balance for input and output power. The formulated optimal design problem is implemented to a non-linear programming algorithm to find minimum power loss. The performance of optimal ly designed Kopp Ball Variator shows that efficiency is increased about 5-10% compare to a commercial unit.