• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.87-97
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• 1998

This paper describes an analysis of tunable characteristic for magnetically tunable E-plane type finline filter on a ferrite substrate. The proposed design is based on using of quarter wavelength transmission line for compensating the negative length transmission line of end K-inverters of E-plane type waveguide filters and the tunable characteristics of designed filters are analyzed. The analysis results of filter and inverter structure loaded with finline on a ferrite substrate are obtained using the edge based finite element method including higher order mode effects. The X-band experimental results for bilateral and unilateral finline magnetically tunable E-plane type waveguide filters agree well with the simulated data.

• International Journal of Automotive Technology
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• v.7 no.7
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• pp.847-852
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• 2006

A fitting process carried out in the automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that applies heat in the outer diameter of a gear to a suitable range under the tempering temperature and assembles the gear and the shaft made larger than the inner radius of the gear. Its stress depends on the yield strength of a gear. Press fitting is a method that generally squeezes gear toward that of a shaft at room temperature by a press. Another method heats warmly gear and safely squeezes it toward that of a shaft. A warm shrink fitting process for an automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by the process produced dimensional change in both outer diameter and profile of the gear so that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of a warm shrink fitting process in which design parameters such as contact pressure according to fitting interference between outer diameter of a shaft and inner diameter of a gear, fitting temperature, and profile tolerance of gear are involved. In this study, an closed form equation to predict the contact pressure and fitting load was proposed in order to develop an optimization technique of a warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, thermal-structural coupled field analysis. Actual loads measured in the field have a good agreement with the results obtained from theoretical and finite element analysis and also the expanded amounts of the outer diameters of the gears have a good agreement with the results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.247-250
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• 2007

In korean traditional wooden structure, to know the critical pass of roof load transmission is very important. to know the critical pass of roof load transmission and to find the role of each dori members, used loading block and load cell. The total weight of loading blocks was 5,8880 N and the number of loading blocks were 16, The experimental fran1e has 1/2 scale. From middle-dori to outside-dori, the linearity of line can't guarantee. So, the distribution of roof load in dori is effected by the initial state of dori. In this research, to remove the effect of initial state, initial deformation was allowed by initial setting.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.25-30
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• 2010

In this paper, a novel notch resonator is proposed based on Rectanglar Split Ring Resonator (R-RSS) element. We represented the electrical characteristics for R-SRR elements coupled with microstrip line, and measured result is compared with electromagnetic simulation (HFSS) result. We also solved equivalent circuit for R-SRR element, and also discussed influences of change structural parameters of R-SRR. the size of R-SRR is the most important parameters for frequency tuning. Also we can make tunable resonator form the basic structure. This novel resonator can apply to design of tunable bandpass filter and voltage control oscillator.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.334-338
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• 2009

In this paper, We report the miniaturization of superconducting microwave power dividers based on lumped element equivalent circuits. To do this, we analyzed a conventional branch-type power divider by using an ABCD matrix under even and odd mode excitation. Then, we calculated each lumped element impedance throughout this analysis of a transmission line matrix. Also we simulated our equivalent circuits made of lumped elements by using a full wave analysis, em Sonnet. Our deign of microwave power divider based on simulated results was fabricated on high-$T_c$ superconducting thin films deposited on MgO substrate. Experimental results were reported in terms of bandwidth, center frequency, and phase difference between $S_{21}$ and $S_{31}$. We confirm that our design will be useful in the future microwave power systum.

• Journal of Power System Engineering
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• v.9 no.1
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• pp.42-49
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• 2005

The vibration analysis of a rectangular plate with stiffeners is formulated by using the transfer stiffness coefficient method (TSCM). This method is based on the concept of the successive transmission of stiffness coefficients which are defined as the relationship between the force vector and the displacement vector at an arbitrary nodal line. In order to confirm the validity of the present method, bending vibration analysis for a rectangular plate with stiffener is carried out on a personal computer by using the present method and the finite element method (FEM). Through comparing computational results of the TSCM and the FEM, the effectivness of the TSCM from the viewpoint of computational cost, that is, computational time and storage is demonstrated.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.122-126
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• 1988

This paper deals with an application of an expert system to transmission line fault diagnosis using alarm information line possible solution can be obtained even in case that the cause of alarms is due to relays, circuit breakers or alarm systems. The expert system diagnoses not only any possible fault element, but also normal or abnormal misoperations. Also, this system can give any possible answers only when the sum of appropriate error indices assigned to false operation of devices is less than the appropriate criterion specified in advance. This paper is written in Official Projection System-Version 5 (OPS-5) which is one of the AI languages.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.377-383
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• 2015

Torsion mode or bending mode of drive-line for rear-wheel drive vehicle exists in low frequency band. If resonance exists there between natural mode of driveline and powertrain excitation force, drive-line will manifest excessive vibration response. Also, the vibration response can be transmitted to vehicle body and can induce booming noise. A vehicle in this study exhibits a booming noise problem under specific transmission gear condition. To draw performance improvement plan, finite element analysis technique was used. Modification was evaluated qualitatively and priorities were derived. Finally, effectiveness of best modification was verified through test and full vehicle FE analysis.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.260-264
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• 2003

In this paper, a $\lambda/4$ hairpin resonator is proposed to reduce the size of planar resonators for a LTCC MLC bandpass filter. The $\lambda/4$ hairpin resonator operates as stepped impedance resonator (SIR) without changing the width of the planar resonator. It is composed of two sections those are parallel coupled line and transmission line. The characteristic impedance of two sections is different each other. The design formulas of the bandpass filter using the coupling element at the arbitrary position are derived from even and odd-mode analysis. The formulas can take account of the arbitrary coupling of lumped ana/or distributed resonators. The advantage of this filter is its abilities to change freely the coupling structure between two resonators. Experimental bandpass filters for 2.4GHz Band are implemented and their performances are shown.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1034-1037
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• 1999

In this paper, we analyze the inductive interference in conductive material around power transmission line. To compute induced eddy currents as well as electromagnetic fields, finite element method(FEM) is used for numerical calculation. The characteristics of conductive material such as gas pipeline, overhead guide wires, conducting earth and so on are taken account of FEM analysis. This research also shows that mitigation wire reduces amount of eddy current in buried gas pipe line.