• 마이크로전자및패키징학회지
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• 제9권3호
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• pp.13-17
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• 2002

LTCC를 이용하여 2차원, 3차원 회로를 구성하는 경우에 R, L, C의 수동소자 이외에 stripline이나 microstripline인 같은 전송선로들이 첨가되게 된다. 따라서 이러한 전송선로들에 대한 정확한 분석을 필요로 하게 된다. 전송선로의 특성에서 유전체의 유효 유전율과 유전체 손실값, 도체의 유효 전기전 도도와 같은 물성치와 도체 및 유전체 표면의 거칠기, 구조의 크기와 같은 기하학적인 특성들이 영향을 주게 된다. 본 연구에서는 스트립라인 구조을 대상으로 위의 물성치와 구조에 관한 변수들을 정량화 함으로써 stripline구조를 분석하고 그 특성을 정량화하였다.

• ETRI Journal
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• 제30권4호
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• pp.495-505
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• 2008

This paper presents a parallel processing searcher structure for the initial synchronization of a direct sequence ultra-wideband (DS-UWB) system, which is suitable for the digital implementation of baseband functionalities with a 1.32 Gsample/s chip rate analog-to-digital converter. An initial timing acquisition algorithm and a data demodulation method are also studied. The proposed searcher effectively acquires initial symbol and frame timing during the preamble transmission period. A hardware efficient receiver structure using 24 parallel digital correlators for binary phase-shift keying DS-UWB transmission is presented. The proposed correlator structure operating at 55 MHz is shared for correlation operations in a searcher, a channel estimator, and the demodulator of a RAKE receiver. We also present a pseudo-random noise sequence generated with a primitive polynomial, $1+x^2+x^5$, for packet detection, automatic gain control, and initial timing acquisition. Simulation results show that the performance of the proposed parallel processing searcher employing the presented pseudo-random noise sequence outperforms that employing a preamble sequence in the IEEE 802.15.3a DS-UWB proposal.

• 한국전자파학회논문지
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• 제18권2호
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• pp.118-125
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• 2007

본 논문에서는 평행 결합 버섯 구조를 이용하여 대역 통과 필터의 고조파 성분을 제거하였다. Double positive(DPS)전송 선로인 마이크로스트립 라인과double negative(DNG)전송 선로인 버섯 구조 사이에서는 격리된 마이크로스트립 라인과 버섯 구조의 교차되는 분산 곡선 주파수 대역에서 강한 결합이 복소 전파 상수로 인해서 발생한다. 교차되는 분산 곡선 주파수에서 강한 결합으로 인하여 전파가 전파를 하지 못하기 때문에 이와 같은 구조는 대역 저지 필터로 이용할 수 있는 것이다. 제안된 대역 저지 필터는 공진기를 이용한 형태가 아니라 평행 결합 전송 선로를 이용하였기 때문에 넓은 대역폭을 가지고 DPS와 DNG 전송 선로 사이의 강한 결합으로 인해서 소형화에 유리하다는 장점을 가지고 있다. 본 논문에서는 중심 주파수 4 GHz, 3 dB fractional 대역폭은 40%인 평행 결합 대역 저지 필터를 설계하였고, 이를 두 가지 종류의 대역 통과 필터의 고조파 모드를 억제하는데 이용하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.597-600
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• 2009

Sound transmission loss (TL) is experimently investigated on the multi-layered panel used for the floor of a tilting train. Measurement of the intensity transmission loss is performed according to ASTM E 2249-02. The floor structure consists of corrugated steel panel, glass wool, plywood and cover. On the corrugated steel panel, TL drop by local resonance is considered and the TL improvement effect by damping treatment is estimated. Total sound transmission loss of the entire floor structure is obtained and the contribution of each layer is examined.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.605-614
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• 2010

In this paper, the initial behavior of transmission tower was analyzed. This tower was firstly constructed by rock anchor foundation in domestic 154 kV transmission line and wireless real-time monitoring system was installed to obtain the measured data for analysis of the structure behavior. For this purpose, 16 strain gauges was installed in anchors of foundation and strain gauges, clinometers, anemoscope and settlement sensors was installed at superstructure. As the results, the main factor which influence the behavior of superstructure is wind velocity, wind direction, rainfall and temperature change. Especially, the uplift load at stub of transmission structure revealed about 35.4 percentages of design load. Hereafter the long term stability will be analyzed.

• Structural Engineering and Mechanics
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• 제31권3호
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• pp.241-264
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• 2009

In this paper, the dynamic behavior for a group of transmission towers linked together through electrical wires and subjected to a strong ground motion will be investigated in detail. In performing the seismic analysis, the wires and the towers concerned are modeled, respectively, by using the efficient cable elements and the 3-D beam elements both considering geometric nonlinearities. In addition, to enhance the reliability and applicability of analytical outcome, a sophisticated soil-structure interaction model will be utilized in analyses. The strength capacities and the fracture occurrences for the main members of the tower are examined with the employment of the appropriate strength interaction equations. It is expected that by aid of this investigation, those who are engaged in code constitution or in practical designing of transmission towers may gain a better insight into the roles played by the interaction force between towers and wires and by the configurations of transmission lines under strong earthquake.

• 대한전자공학회논문지
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• 제26권8호
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• pp.1227-1237
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• 1989

In this paper, we propose a lossless progressive image transmission scheme using hierarchical pyramid structure and classified vector quantizer in DCT domain. By adopting DCT to the hierarchical pyramid signals, we can reduce the spatial redundance. Moreover, the DCT coefficients can be encoded efficiently by using classified vector quantizer in DCT domain. The classifier is simply based on the variance of a subblock. Also, the mirror set of training set of images can improve the robustness of codebooks. Progressive image transmission can be achieved through following processes: from top to bottom level of planes in a pyramid, and from high to low AC variance class in a plane. Some simulation results with real images show that the proposed coding scheme yields a good performance at below 0.3 bpp and an excellent result at 0.409 bpp. The proposed coding scheme is well suited for lossless progressive image transmission as well as image data compression.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.468-473
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• 2004

The objective of this paper is to analyze the characteristics of wave transmission through various junctions in coupled beams. The in-plane vibration as veil as the out-of-plane vibration are generated due to the wave conversion at the junctions in the coupled beams. The out-of-plane vibration is associated with propagation of out-of-plane waves (flexural waves). The in-plane vibration is associated with propagation of in-plane waves (longitudinal and torsional waves). In order to effectively reduce vibration and structure-borne noise, it is necessary to understand the characteristics of wave conversion at various junctions in the coupled structures. The numerical results in this paper have showed the characteristics of wave transmission through various junctions in coupled beams. Those could be helpful to designer to develop the idea to reduce vibration and structure-borne noise.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.646-650
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• 2001

In this paper, it is presented that the effect of air gap insertion in testing the transmission loss of sound barrier using structural vibration system. In this study, we use the APAMAT based on the structure-borne-noise. The measured results show that air gap insertion improves transmission loss as results of test based on the air-borne-noise. The measured results are compared with the predicted transmission loss using the transfer matrix method. The predicted results were found to be in reasonable agreement with measured results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1656-1660
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• 2008

Internal noise level of a train running in tunnel is influenced by sound transmission coefficients of floor, side door, window and gangway as well as by the sound power levels of major noise sources. The structure of a gangway should be strong enough for the safety of passengers while it should be flexible enough for the movement of a train in curves. Due to this the sound transmission coefficients of gangways are relatively low compared to those of carbody structure. The effect of the sound transmission coefficient of the gangway is studied in this paper in regards to the existence of end doors.