• 전자공학회논문지A
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• 제33A권2호
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• pp.69-77
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• 1996

We analyzed wideband propagation characteristics of a microstrip transmission line based on FR-4 composite substrate using the wideband complex dielectric constant model and the phenomenological loss equivalence method. The loss calculated by constant relative permittivity and loss tangent is greatly overestimatd compared to that calculated by the frequency-dependent complex relative permittivity. This wideband analysis can be helpful to characterize high-speed and high-density transmission lines associated with the wideband dielectric characteristics and shows that the FR-4 composite substrate has high potential of high frequency circuit applications in terms o fthe propagation loss.

• 수산해양기술연구
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• 제58권2호
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• pp.130-140
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• 2022

Recently, wideband acoustic technology has been introduced and started to be used in fisheries acoustic surveys in various waters worldwide. Wideband acoustic data provides high vertical resolution, high signal-to-noise ratio and continuous frequency characteristics over a wide frequency range for species identification. In this study, the main characteristics of wideband acoustic systems were elaborated, and a general methodology for wideband acoustic data analysis was presented using data collected in frequency modulation mode for the first time in Republic of Korea. In particular, this study described the data recording method using the mission planner of the wideband autonomous acoustic system, wideband acoustic data signal processing, calibration and the wideband frequency response graph. Since wideband acoustic systems are currently installed on many training and research vessels, it is expected that the results of this study can be used as basic knowledge for fisheries acoustic research using the state-of-the-art system.

• Smart Structures and Systems
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• 제1권3호
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• pp.257-266
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• 2005

In Lamb wave detection of damages in smart structures, the excitation pulse is usually designed as a narrow band burst wave for the convenience of analysis and recognition. However, the wideband excitation can excite more modes in plate/shell structure and thus provides extra information for changes of the structure. This paper presents a method that can extract information in wideband Lamb wave signals. By transforming the detected signals into various sub-frequency band, the measured signal can be converted to its equivalences of narrow band excitations, therefore, the information in different frequency bands can be acquired from a single test and in the same time the complicity of wideband signal can be simplified. Some test results are provided to verify this method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3731-3750
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• 2014

This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

• 한국통신학회논문지
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• 제42권4호
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• pp.703-715
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• 2017

본 논문은 장거리 공중-지상 가시선 링크에서 대용량 영상정보용 데이터링크의 무선채널 특성을 분석하고 공중-지상 채널의 협대역 및 광대역 간섭이 대용량 데이터링크의 수신 신호에 미치는 영향을 수학적으로 분석하는 방법을 제안한다. 제안된 성능분석 방법을 이용하여 통신거리에 따른 수신성능을 분석하였고 지면 반사파의 협대역 및 광대역 간섭에 의해 통신거리가 제한됨을 확인하였다. 또한 수신 안테나를 상향으로 제어하는 방법의 성능분석 결과, 협대역뿐만 아니라 광대역 간섭도 효과적으로 제거함으로써 별도의 등화기를 포함하지 않은 기존 대용량 데이터링크 장비로도 통신거리를 증가시킬 수 있음을 확인하였다.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2010년도 춘계학술대회
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• pp.53-55
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• 2010

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1199-1212
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• 2019

This paper proposes two wideband spectrum sensing approaches: (i) method A, the cumulative sum (CUSUM) algorithm with short-time Fourier transform, taking advantage of the time-frequency analysis for wideband spectrum. (ii)method B, the quickest spectrum sensing with short-time Fourier transform and compressed sensing, shortening the time of perception and improving the speed of spectrum access or exit. Moreover, method B can take advantage of the sparsity of wideband signals, sampling in the sub-Nyquist rate, and it is more suitable for wideband spectrum sensing. Simulation results show that method A significantly outperforms the single serial CUSUM detection for small SNRs, while method B is substantially better than the block detection based spectrum sensing in small probability of the false alarm.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.20-23
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• 1999

In this paper, The Split Model Analysis Algorithm, which can generate the wideband speech signal from the spectral information of narrowband signal, is developed. The Split Model Analysis Algorithm deals with the separation of the $10^{th}$ order LPC model into five cascade-connected $2^{nd}$ order model. The use of the less complex $2^{nd}$ order models allows for the exclusion of the complicated nonlinear relationships between model parameters and all the poles of the LPC model. The relationships between the model parameters and its corresponding analog poles is proved and applied to each $2^{nd}$ order model. The wideband speech signal is obtained by changing only the sampling rate

• 한국항행학회논문지
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• 제11권3호
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• pp.274-280
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• 2007

초 광대역 신호는 상대적으로 낮은 주파수에서 매우 넓은 대역폭을 갖는 방사 스펙트럼을 특징으로 하고 있다. 본 논문에서는 잡음과 동일채널간섭 채널에서 M-ary 상관 수신기 구조로 된 초 광대역 시스템의 비트 오율, 패킷 오율, 데이터 처리율 성능을 분석한다. UWB 시스템의 성능을 평가하기 위하여 하나 이상의 펄스 위치 변조 신호로 구성된 UWB 통신 파형을 사용하였다. 본 논문에서 사용된 M-ary PPM 신호는 시스템 성능 해석의 간략화를 위하여 균일하게 상관된 PPM 신호를 정의하였다. 시스템 성능의 해석을 통하여 무선 채널 에러는 처러율 성능을 감소시키며 hybrid ARQ 기법을 통하여 효과적으로 증가시킬 수 있음을 알 수 있었다. 또한, 성능 개선 기법과 사용된 파라미터를 통하여 초 광대역 시스템의 데이터 처리율 비교를 수행하였다. 성능 평가 과정을 통하여 무선 채널과 hybrid ARQ 기법의 영향을 신호 대 잡음 전력비에 따른 PER 및 처리율을 평가하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.552-555
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• 2002

Wideband CDMA is one of the radio access technologies for the third generation in which voice is the basic service. There has been lot of research work in order to find out the suitable transmission scheme to meet the requirement of accommodating variable type of services in Wideband-CDMA. This paper studies the behavior of different services using different transmission schemes in Wideband CDU and compares their performance in terms of BER. Different transmission schemes are found to be suitable for different services. Transmission schemes used are- fixed processing gain scheme also called as variable bandwidth scheme, single code transmission and multicode transmission. It is found that fixed processing gain scheme is suitable fur high data rates. Single code transmission is suitable fer low data rates where as multicode transmission is suitable for low and medium data rates.