• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2908-2924
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• 2019

Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is widely applied in wireless communication by virtue of its excellent properties in data transmission rate and transmission accuracy. However, as a major drawback of MIMO-OFDM systems, the high peak-to-average power ratio (PAPR) complicates the design of the power amplifier at the receiver end. Some available PAPR reduction methods such as selective mapping (SLM) suffer from high computational complexity. In this paper, a low-complexity SLM method based on active constellation extension (ACE) and joint space-time selective mapping (AST-SLM) for reducing PAPR in Alamouti STBC MIMO-OFDM systems is proposed. In SLM scheme, two IFFT operations are required for obtaining each transmission sequence pair, and the selected phase vector is transmitted as side information(SI). However, in the proposed AST-SLM method, only a few IFFT operations are required for generating all the transmission sequence pairs. The complexity of AST-SLM is at least 86% less than SLM. In addition, the SI needed in AST-SLM is at least 92.1% less than SLM by using the presented blind detection scheme to estimate SI. We show, analytically and with simulations, that AST-SLM can achieve significant performance of PAPR reduction and close performance of bit error rate (BER) compared to SLM scheme.

• 방송공학회논문지
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• 제22권4호
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• pp.509-518
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• 2017

GPU를 탑재한 여러 대의 PC를 클러스터(서버-클라이언트 구조)로 구성함으로써 고해상도 디지털 홀로그램을 고속으로 생성할 수 있다. 그러나, 비디오 홀로그램의 경우, PC 사이의 데이터 전송 시간이 프레임 수에 비례하여 선형적으로 증가하기 때문에 비디오 홀로그램을 고속 생성하는 데 있어 큰 걸림돌이 된다. 본 논문에서는 이러한 데이터 전송 시간의 증가를 해결하기 위해 멀티쓰레드를 활용하는 방법을 제안한다. 기본적으로 각 클라이언트 PC에서의 홀로그램 생성은 서버로부터 광원 정보 획득, GPU를 이용한 CGH 연산, 서버로의 결과 전송의 과정으로 이루어지는데, 각 과정을 순차적으로 하지 않고 멀티쓰레딩을 통해 병렬로 수행함으로써 전체 홀로그램 생성 시간에서 데이터 전송 시간의 비율을 크게 줄일 수 있다. 실험을 통해, 150 프레임을 가지는 고해상도 비디오 홀로그램을 생성하는 시간을 약 30% 줄일 수 있음을 확인하였다.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.65-68
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• 2000

In this paper, as a compatible software radio transmission system, Digital-Radio conversion system which can directly change the digital signal generated by the logic circuit into radio signal is proposed. By the vector synthesis method, the digital signals can change directly into radio signal. If such a circuit is realized, RF circuit and an antenna can be composed by the simple one device, and the radio is directly controlled and performed by the software processing which is the essence of software radio. This Digital-Radio conversion system of this paper give many number of communication channels being offered by PN code and offer a hardware design flexibility by digitization, therefore it decrease the percentage ratio of hardware of system and give a more flexible function of software basis. In this paper, this proposed Digital-Radio conversion system is called D/R converter, and the principle of this D/R converter, radio signal generation algorithm is explained and the performance characteristics of proposed algorithm is shown in time base by the computer simulation method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.598-601
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• 2004

In this paper, we suggest method that change odors to digital data. For this, we selected emotional adjective of odors as olfactory receptor This emotional adjective(expressional receptor) is about 40. Each odors are expressed by adjective equivalent to oneself. Expressed odors as emotional receptor is encoded as proposed method for transmission, and after transmission, It should be decoded for expression again. The applied decoding method is fuzzy c-means clustering algorithm(FCMA). But, because odor data is expressed to 40 dimensions, FCMA uses a lot of computing times and memories. To solve this problem, after we reduce dimension through principal component analysis(PCA), we use FCMA algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.947-949
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• 1987

This paper describes the design of echo cancslling method(ECM) for transmission with full-duplex which ie transmitted on "2B+D"(144kbps)data through two-wire loop plants. The design objective is 40dB attenuation with a signal-to-noise ratio of $10{\sim}20dB$. Since the transhybrid loos can be as low as $6{\sim}10dB$, the required attenuation of the echo signal is on the order of $50{\sim}55dB$. The used algorithms based on the sign algorithm, and have been improved by using adoptive reference voltage level algorithm.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.110-113
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• 2003

In this paper, the multi-channel high speed data acquisition system is implemented. This high speed signal processing system for 3-D image display is applicable to the manipulation of a medical image processing, multimedia data and various fields of digital image processing. In order to convert the analog signal into digital one, A/D conversion circuit is designed. PCI interface method is designed and implemented, which is capable of transmission a large amount of data to computer. In order to, especially, channel extendibility of images acquisition, bus communication method is selected. By using this bus method, we can interface each module effectively. In this paper, 32-channel A/D conversion and PCI interface system for 3-dimensional and real-time display of the retina image is developed. The 32-channel image acquisition system and high speed data transmission system developed in this paper is applicable to not only medical image processing as 3-D representation of retina image but also various fields of industrial image processing in which the multi-point realtime image acquisition system is needed.

• 한국통신학회논문지
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• 제15권10호
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• pp.829-841
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• 1990

본 논문에서는 우리 나라 디지털 다중화 계위 5차군 전송속도 564.993Mb/s를 실제의 광전송 데이터 속도라 가정하고, 국내 565Mb/s 광전송시스템을 유지 보수할 뿐만 아니라 디지털 광전송용 통신망을 B.S.I.화하기 위하여, 단국중계장치에서 기존의 전송로부호들 중 최적의 전송로부호라 사료되는 mBIZ 전송로부호를 이용한 새로운 전송로 프레임 구조를 제안한다. 제안한 프레임 구조대로 565Mb/s 광전송용 단국중계장치에서 순수정보신호계열의 속도를 변환한 후 pulse stuffing 하는 방식으로 시스템 하드웨어를 실현시킨 결과, 전송 에러에 의한 연속적인 시스템 에러 파급 현상 즉, 도미노 현상을 방지할 수 있었으며, timing jitter와 동부호연속수도 억압할 수 있었다. 또한 광단국장치에서의 total BER을 10정도까지 향상시킬 수 있기 때문에 시스템 SNR을 2dB 정도 개선할 수 있었다.

• 전자공학회논문지S
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• 제36S권11호
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• pp.9-14
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• 1999

본 논문은 10Gbps 광 전송 장치의 저속부와 고속부 셀프 간에 77.76Mbps의 10라인의 전송 방법인 H-BUS 방식보다 효율적인 622Mbps 의 1라인으로 전송하기 위하여 622Mbps로 수신되는 데이터를 동기식 디지털 계위(SDH)에 정의된 동기식 전달방식(STM)-64 프레임 형태로 정렬할 수 있는 리프레임 방법을 설명하였으며 이를 VHDL로 설계하여 10Gbps 광 전송 장치의 T14U 보드의 10G-S4 ASIC내에 적용하였다.

• 한국멀티미디어학회논문지
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• 제18권4호
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• pp.541-545
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• 2015

Wireless power transmission which can transmit the electrical power through the air is the promise technology. In this paper, the effects of wireless power transmission using magnetic resonance method have been studied on coil material, resonance frequency, and antenna type. We have found copper tube as a coil material had the better characteristics than that of enameled wire, and the optimal resonance frequency was 13.6MHz in the range of from 1MHz to 20MHz. And the double square spiral type antenna as a load coil was the best. The power transmission distance by magnetic resonance method with 13.6MHz was 150 cm.

• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.21-29
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• 2020

This paper presents an effective single image haze removal using edge-preserving and adaptive transmission estimation to enhance the visibility of outdoor images vulnerable to weather and environmental conditions with computational complexity reduction. The conventional methods involve the time-consuming refinement process. The proposed transmission estimation however does not require the refinement, since it preserves the edges effectively, which selects one between the pixel-based dark channel and the patch-based dark channel in the vicinity of edges. Moreover, we propose an adaptive transmission estimation to improve the visual quality particularly in bright areas like sky. Experimental results with various hazy images represent that the proposed method is superior to the conventional methods in both subjective visual quality and computational complexity. The proposed method can be adopted to compose a haze removal module for realtime devices such as mobile devices, digital cameras, autonomous vehicles, and so on as well as PCs that have enough processing resources.