• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.79-85
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• 2023

To make normal operation of S-Band PSR(Primary Surveillance Radar) which are in operation near distance, Minimizing the mutual frequency interference was studied in this paper. First, the phenomenon of radar receiver was analyzed when the interference between PSR was occurred. And next, the proper S-Band Bandpass filter(BPF) was chosen to deal with the interference. And inhibition performance of BPF was verified by comparative analysis of Radar's RF reception characteristic before and after of BPF application. There is 6.4~7.7 dB passband attenuation when BPF was applied at Radar receiver. So the PSR probability of detection were compared and analyzed to check the radar detection performance was deteriorated or not, And this result proved the usefulness of this study.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.33-40
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• 2014

In this paper we propose new image coding using wavelet transform. The new method constructs hierarchical bit plane and progressively transports each bit plane. The Proposed algorithm not only supports multi-resolution, dividing original image into special band and various resolution using Antonini's wavelet basis function but also reduces blocking effects that come into JPEG. In encoding time this algorithm considers each band characters and priority of transport order, and applies to fast search of image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.100-107
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• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.866-873
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• 2006

In this paper, we proposed and fabricated the single-feed dual-band circular patch antenna for S-DMB(Satellite-Digital Multimedia Broadcasting) and ITS(Intelligent Transport Systems) services. The manufactured dual-band antenna showed that the measured -10 dB bandwidth and the minimum return loss was 90 MHz and -35 dB for S-DMB, 180 MHz and -18 dB for ITS, respectively. It is noticed that the measured and the simulated results are agreed well. And the antenna gain of S-DMB and ITS has 2.3 dBi and 2.7 dBi, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.1-8
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• 2011

In this paper, a microstrip bandpass filter(BPF) with 3 dB bandwidth of more than 50 % at center frequency of 30 GHz was implemented. The implemented BPF is to be used as ASK(Amplitude Shift Keying) transmission and reception filters in IF band for THz transmitter and receiver capable of 10 Gb/s wireless data transmission. The microstrip BPF with ultra-wideband characteristics was implemented using a stepped-impedance lowpass filter(LPF) and a composite quarter-wave short stubs where the LPF is functioning as attenuating the upper stopband and quarter-wave short stubs is functioning as attenuating the lower stopband. The measured results are as follows; the insertion loss is 0.65 dB at 30 GHz, the stopband characteristics are -10 dB and -16 dB at 10 GHz and 50 GHz, respectively, and the passband flatness is ${\pm}0.5$ dB at 20~40 GHz.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.490-495
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• 2016

In the present study, a microstrip-fed monopole antenna is proposed for wireless local area network (WLAN) operations which cover dual band of 2.4 GHz (2.4 ~ 2.484 GHz) and 5 GHz (5.15 ~ 5.825 GHz). In order to obtain its compact structure and good omnidirectional radiation patterns, a modified inverted L-shaped slot separated from ground for impedance matching in 5 GHz band is etched on 2.4 GHz printed monopole antenna. The proposed antenna is designed and fabricated on a FR4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of $30{\times}45mm^2$. The measured impedance bandwidths (${\mid}S_{11}{\mid}{\leq}-10dB$) of fabricated antenna are 270 MHz (2.22 ~ 2.48 GHz) in 2.4 GHz band and 890 MHz (5.08 ~ 5.97 GHz) in 5 GHz band respectively. In particular, high gain of more than about 4 dBi and good omnidirectional radiation patterns have been observed over the entire frequency band of interest.

• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.106-114
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• 1997

In this paper, we propose an efficient coding method of remotely sensed satellite image using region classification and interband prediction. This method classifies each pixel vector considering spectral characteristics of satellite image data. Then we perform the classified intraband VQ to remove spatial (intraband) redundancy for a reference band image. To remove interband redundancy effectively, we perform the classified interband prediction for the remaining band images. Experiments on LANDSAT TM satellite image show that coding efficiency of the proposed method is better than that of the conventional Gupta's method.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.462-467
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• 2020

대역사전의 구축은 저자원 언어쌍 간의 기계번역의 품질을 높이는데 있어 중요하다. 대역사전 구축을 위해 기존에 제시된 방법론 중 단어 임베딩을 기반으로 하는 방법론 대부분이 영어-프랑스어와 같이 형태적 및 구문적으로 유사한 언어쌍 사이에서는 높은 성능을 보이지만, 영어-중국어와 같이 유사하지 않은 언어쌍에 대해서는 그렇지 못하다는 사실이 널리 알려져 있다. 본 논문에서는 단어 임베딩을 기반으로 부트스트래핑을 통해 대역사전을 구축하는 방법론을 제안한다. 제안하는 방법론은 소량의 seed 사전으로부터 시작해 반복적인 과정을 통해 대역사전을 자동으로 구축하게 된다. 이후, 본 논문의 방법론을 이용해 한국어-영어 언어쌍에 대한 실험을 진행하고, 기존에 대역사전 구축 용도로 많이 활용되고 있는 도구인 Moses에 사용된 방법론과 F1-Score 성능을 비교한다. 실험 결과, F1-Score가 약 42%p 증가함을 확인할 수 있었으며, 초기에 입력해준 seed 사전 대비 7배 크기의 대역사전을 구축하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.621-629
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• 2008

This paper presents a low temperature co-fire ceramics(LTCC) Upconverter for a Ka-band OBS satellite transponder in order for size reduction which is one of the most important requirement for satellite components. A S-band low-pass filter(LPF), a K-band band-pass filter(BPF), and an upconverting MMIC mixer are embedded in the multi-layer structure of the upconverter. All spurious can be selectively rejected by employing a modified Elliptic low pass filter with a multi-pole structure for the S-band LPF. Also an improved performance of out-of-band rejection can be obtained. At the K-band BPF design a layer coupled configuration is employed. The upconverting mixer is an MMIC diode mixer with a double-balanced configuration. Conversion loss and isolation of the upconverter are 9 dB and 51 dBc, respectively. The size of the LTCC upconverter is only $8{\times}7{\times}0.6mm^3$ which is one-third for the thin-film based upconverter.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.755-758
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• 2000

본 논문에서는 AMR(Adaptive Multi-Rate)를 이용하여 광대역 음성부호화기를 설계하였다. 16kHz로 샘플링 된 입력 신호를 QMF 필터에 의해 두 개의 대역으로 나누어, 각각 decimation하여 두 개의 8kHz 샘플링 신호로 변환시킨 후 저대역(0Hz-3400Hz)의 신호와 고대역(3400Hz -7000Hz)의 신호로 나누어 각각 부호화한다. 나누어진 두 개의 협대역 음성신호는 AMR(Adaptive Multi-Rate)과 ATC(Adaptive Transform Coding)을 사용하여 각각 부호화되어 전송된다. 두 대역으로부터 부호화된 정보는 20.2kbps에서 12.75kbps까지의 전송률을 갖고, 수신단에서는 각 대역을 AMR과ATC방법으로 역부호화하여 음성신호를 합성한다. 설계된 광대역 음성부호화기의 성능을 평가하기 위해 ITU-T의 표준안인 G.722를 포함하여 MOS 시험을 하였다.