• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.49-56
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• 1994

The purpose of this study is to construct a total design & manufacturing system for the Space-Truss structure. In this study, we choose the transmission tower as the study model to show the possibility of a Total System for another space truss structure. We are confident that this total system should provide more convenience, accuracy and should help to save time from the design stage to construct stage of the transmission tower.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.605-614
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• 1995

In the automatic transmission using planetary gear there exists nonlinearities due to the finite difference between gear ratios, which yield torque hole during shift and influence on the ride quality and life of clutch. Based on the reaction carrier and converter turbine speed sliding functions are defined. Nonlinear closed-loop control laws are derived using them. Computer simulation shows that the closed loop design is better than the open loop design and semi-closed loop design.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.163-170
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• 2002

A new seismic design criteria of electric transmission and substation facilities has been proposed. For this propose, the historic data of the earthquake damage and the state-of-the-art of the facilities were carefully reviewed and evaluated. Based on the results, a most reasonable and efficient design criteria has been extracted and proposed for the practical design of the facilities. The criteria is expected to be effectively used for obtaining the seismic safety of newly constructed or extensioning facilities. However, an independent criteria is required to evaluate and improve the seismic capacity of existing facilities

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.993-996
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• 2007

Depending on applications where transmission bandwidth, wire distance, power consumption and EMI environments vary, design trade-offs must be made to optimize the display interface. After introducing the digital display interface architecture, topics such as cost, EMI, signal integrity, scalability and content protection are discussed with available techniques. Implementation issues are discussed regarding their cost and design complexity. Existing standards are reviewed and comparison on their strengths and shortcomings are discussed.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.127-128
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• 2007

A dual band LNA is designed to set input matching and noise matching with source transmission feedback for wireless LAN applications. Some design techniques for the transmission line feedback of the dual band LNA have been developed with input and output design equations. The measured results shows close agreement with the simulated performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2305-2310
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• 2011

This paper describes a design of dual band balanced amplifier using a lefted handed meta-material transmission line structure for high frequency application. Meta-material transmission lines have been known to have dual band frequency responses. A dual band branch line hybrid coupler is designed using the meta-material transmission lines, and measured at first. Two identical dual band amplifiers are also designed, built and tested using the same meta-material transmission structure. The proposed dual band balanced amplifier is composed of those dual band branch line hybrid coupler and amplifiers. In order to suggest an design example, a prototype of dual band balanced amplifier is built and measured at the dual frequencies, 1800MHz($f_1$) and 2300MHz($f_2$). The simulation and measurement show that the fabricated balanced amplifier operates well at the desired dual frequencies bands with the gain of 11.12dB and 17.67dB at $f_1$ and $f_2$, respectively, with a good agreement with the simulation results.

• ETRI Journal
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• v.36 no.2
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• pp.286-292
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• 2014

This paper presents a compact structure composed of an upper high-impedance transmission line, a middle extended parallel coupled line, and a pair of inter-coupled symmetrical stepped impedance stubs. Detailed investigation into this structure based on an equivalent circuit analysis reveals that this proposed structure exhibits a quasi-elliptic low-pass filtering response with three transmission zeros. Moreover, the positions of the three transmission zeros can be tuned and reallocated flexibly by choosing the proper circuit parameters. Finally, the design concept is validated through the design, fabrication, and measurement of two exemplary low-pass filters (LPFs) with one single unit and two cascaded asymmetric units. The measured results agree well with the simulated results. In addition, in the range of $1.42f_c$ to $7.03f_c$, the fabricated quasi-elliptic LPFs experimentally demonstrate a very wide upper-stopband of 20 dB using a compact size of only $0.0089{\lambda}_g{^2}$, where ${\lambda}_g$ is the guided wavelength of a $50{\Omega}$ transmission line at the central frequency.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.14-19
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• 2016

Transmission error (TE) is the most important cause of gear noise and vibration because TEs affect the changes of the force and the speed of gears. TE is usually expressed as an angular deviation, or a linear deviation measured at the pitch point and calculated at successive positions of the pinion as it goes through the meshing cycle. Accurate measurement of TE for gear transmission will provide a reasonable basis for gear design, manufacturing processes and quality control. Therefore, in order to study the accuracy of the gear transmission, stability, TE, vibration and noise after gear micro-geometry modification, a gear transmission test rig is proposed in this paper, which is based on the existing technical conditions, by using reasonable testing methods, hardware and a signal processing method. All of the details and the experience can be taken into consideration in the next upgraded test rig.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.418-425
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• 2008

In this paper, we propose two different types of cooperative transmission protocols, referred to as spatial multiplexing with receive diversity (SMRD), that are bandwidth-efficient. We show that the BER performance can be significantly improved with a proper design of SMRD protocol under the AF (Amplify-and-Forward) and the DF (Decode-and-Forward) modes of relaying, when there is no interference among all symbols transmitted in the same time slot. BER analysis and our simulation result show that the proposed transmission protocol achieves a significant gain over no-cooperation (direct transmission) without any bandwidth expansion.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.234-239
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• 2010

An inductive coupler, which feeds communication to the electric power transmission line, is required to establish Power Line Communication(PLC). The electro-magnetic property of magnetic core and design technology for coupler are very important to manufacture an inductive coupler for power transmission line. The magnetic core with superior electro-magnetic property was manufactured by using nanocrystalline alloy and an inductive coupler, which can operate at the maximum 2,000 A current, was designed and manufactured by establishment of current saturation, signal out winding, and electromagnetic simulation in this study. Communication speed of 14 Mbps in 600 meter communication distance of the real electric power transmission line was obtained by using the inductive coupler and application possibility of the inductive coupler for the electric power transmission line was certified.