• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.226-232
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• 2003

In this paper, design rule of power island is studied. Power island have a defect that increase transfer noise when each power bus structure is resonant. So, in this paper, resonances are suppressed for various noise source positions and in order to improve noise characteristics, it is suggested EGI in order to improve noise characteristic. At the simulation result, the least resonance is showed for various noise source position and transfer impedance with power bus resonance is reduced about 11 $\Omega$ by EGI.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.237-243
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• 2017

This paper presents an analysis of the electromagnetic interference of a heterogeneous power bus where electromagnetic bandgap (EBG) cells are irregularly arranged. To mitigate electrical-noise coupling between high-speed circuits, the EBG structure is placed between parallel plate waveguide (PPW)-based power buses on which the noise source and victim circuits are mounted. We examine a noise suppression characteristic of the heterogeneous power bus in terms of scattering parameters. The characteristics of the dispersion and scattering parameters are compared in the sensitivity analysis of the EBG structure. Electric field distributions at significant frequencies are thoroughly examined using electromagnetic simulation based on a finite element method (FEM). The noise suppression characteristics of the heterogeneous power bus are demonstrated experimentally. The heterogeneous power bus achieves significant reduction of electrical-noise coupling compared to the homogeneous power buses that are adopted in conventional high-speed circuit design. In addition, the measurements show good agreement with the FEM simulation results.

• Journal of electromagnetic engineering and science
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• v.6 no.4
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• pp.197-202
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• 2006

This paper presents a study on the differential signaling for the rectangular power-bus structure. The full-wave modal analysis method analyzes how the differential-signaling can lower the power-bus resonance noise levels. The methodology is validated by the use of the FDTD method and reference measurements.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.42-47
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• 2017

In these days, the size of urban is growing and the function of city becomes complicated. And also, in city, people lives a lot. The life of urban is getting closer and linked with neighboring people in many parts. Especially, when peoples are exposing during using public transportation, even though does not be known, in they were living. Seoul is the most crowded place in Korea. In Seoul,The village buses have been serviced to the narrow streets. And people who use this bus, wants to seek the comfort of the ride, air quality and noise during in vehicle. In this paper, we determine the degree of annoyance with the noise inside the town bus in dB scale. And, such a situation was confirmed annoyance see their effect. The Interior noise did not see a big difference in the new car and the old car. Annoyance but also according to the skill of the bus driver remains the difference was confirmed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.658-664
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• 2012

This paper presents an investigation into driveline clonk noise of midi-bus. Test was performed for operational acceleration and pressure, torsional vibration of driveline and FRF to TPA. Wavelet analysis was used to study spectral-time characteristics to all measurement data and specially for torsional vibration, lash analysis was carried out. To investigate the path of the clonk in detail, time domain TPA was introduced. With time domain TPA, the contribution of each path for the clonk was estimated by both subjectively and objectively. As a result, Transmission mount part was came to light as the main contributor of issued clonk. This was verified by reinforcing the bracket of transmission side. And 1D torsional nvh performance simulation model was built with measured torsional vibration. The simulation tool was used for prediction of some clonk behavior in tip in-out transient condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.330-335
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• 2012

A Bus Trunk System for Wind Tower is introduced. A marine cable has been widely used in wind tower or other offshore structure. However, as the electric load capacity is getting increased, the large number of cable lines should be used to cover such a huge amount of electric capacities, which makes the installation make quite difficult due to the heavy weight and volume of the present cables. On the other hand, by using a single bus trunk system line, the power capacity amount of 16 number of cable can be delivered with significant compactness. However, unlike flexible cable, the bus trunk is relatively stiff which could arise resonance phenomenon in the operating condition of wind tower, therefore, the vibration characteristics of bus trunk should be investigated and verify its long-term reliability during the life time of the wind tower.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.1013-1013
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• 2004

Soundscape design is applied for the purpose of expressing the characteristics of places, by supplying suitable background sound for various places expressing their identity. Bus stations are a place for aggregating people using transportation. That is, people go into a station, buy a ticket, and wait for departure or for other passengers. Therefore, they need to create a more comfortable sound environment. This study aims to make bus stations a comfortable place acoustically for users. In this study, analysis on behavior at various locations in the space was performed. Measurements were taken on the approaching path, waiting place, departure and arrival platforms for sound levels and frequency characteristics. In addition, on acoustic specialists evaluation, using questionnaires, was also performed ambient noise, information broadcasting and users dialogue.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.13-18
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• 2003

In this paper, we researched on the improved method for transferring noise which is generated from power island. In general case, the power island has a drawback where the noise transfer increase because of the structural resonance in each power bus. Thus, this paper suggests two improved methods that reduces the noise transfer. First method is to suppress the structural resonance by varying the source of the noise. The second method is to utilize the EGI in order to minimize the EGI in order to minimize the transfer of the noise when the resonance occurs. The simulation analysis shows that the relocation of the noise source dramatically minimized the resonance in power bus and the utilization of EGI has effectively reduced the noise transfer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.354-357
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• 2004

In this paper, a sensitivity analysis technique is presented for performing effective structural optimization of bus system. Design sensitivities are analyzed on natural frequency of bus substructures using super-element. Vibration modes of substructure, which large affect on the global vibration mode of bus B.I.W., are found through the sensitivity analysis using the chain rule. And design variables, which are determined from the sensitivity analysis, are changed through optimum design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1040-1047
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• 2002

In this paper, we investigated noise decoupling on the power bus by the screw connection, used to the mechanical join and grounding of the PCB ground to chassis. The screw connection penetrates the power bus and then it affects noise propagation on the power bus. To verify effect of the screw connection, we compare bare board with board having screws connection with 0.5 mm separation between power bus and chassis. From these results, we observed that the power bus noise was decreased about 5 dB at the frequency range from 0.1 GHz to 1 GHz. Also, we verified that a 4-layer PCB with signal trace had the better signal quality up to 600 MHz by the screw connection. Therefore, these results will be useful in designing to the high speed circuit and chassis.