• 한국항행학회논문지
• /
• 제20권6호
• /
• pp.568-573
• /
• 2016

현재 아날로그 방식의 마을방송 시스템은 기술 적용의 문제 및 시설 노후화로 인한 성능 저하 등의 문제로 인하여 디지털 시스템으로의 전환과 이에 따른 시스템 표준이 요구되고 있다. 효율적인 디지털 무선 마을 방송 시스템의 구축을 위해서 파라미터를 토대로 전파환경 특성에 기반을 두어 전파의 실측값과 예측 값의 비교분석이 필요하다. 본 논문은 지역 환경을 고려하여 도시지역, 산간지역, 평야지역으로 경로를 설정하여 전파 측정을 하였으며, 측정을 통한 실측값과 예측 값을 SMIS (spectrum management intelligence system) 및 Matlab을 이용하여 전계강도 및 오차를 비교분석하였다. 본 논문의 결과는 전파수신 전력 및 지형별 환경 등의 전파 특징을 예측하고 마을 방송 표준의 확립과 시범 사업화를 위한 자료로 활용될 것이다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2022년도 추계학술대회
• /
• pp.362-365
• /
• 2022

4차 산업혁명 기술의 발전으로 인하여 다양한 분야에서의 스마트화가 가속화되고 있다. 해운물류 산업 역시 선진국들을 중심으로 디지털트윈, 사물인터넷, 인공지능 등 첨단 신기술을 접목한 스마트화를 추진 중이다. 국내에서도 변화하는 글로벌 해운물류 흐름에 맞추어 해양수산부를 중심으로 스마트 해운물류 체계 확산전략을 추진하고 있으며 이를 통해 해운물류 스마트화 기반을 조성하고 있다. 본 연구는 이러한 해운물류 스마트화 기반 조성에 따라 입출항, 접안, 상하역 등 변화하는 해운물류 프로세스에 대응하기 위하여 각 운영주체 간 커뮤니케이션의 중요성을 인지하고, 가상의 디지털트윈 환경에서 운영주체 간 의견을 교환할 수 있는 커뮤니케이션 도구의 개념을 제시하고자 한다. 또한, 이러한 커뮤니케이션 도구의 점진적인 개발을 위하여 아키텍처를 비롯한 소프트웨어 설계 모델을 도출하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제18권4호
• /
• pp.1042-1058
• /
• 2024

Terahertz (THz) communication is becoming a key technology for future 6G wireless networks because of its ultra-wide band. However, the implementation of THz communication systems confronts formidable challenges, notably beam splitting effects and high computational complexity associated with them. Our primary objective is to design a hybrid precoder that minimizes the Euclidean distance from the fully digital precoder. The analog precoding part adopts the delay-phase alternating minimization (DP-AltMin) algorithm, which divides the analog precoder into phase shifters and time delayers. This effectively addresses the beam splitting effects within THz communication by incorporating time delays. The traditional digital precoding solution, however, needs matrix inversion in THz massive multiple-input multiple-output (MIMO) communication systems, resulting in significant computational complexity and complicating the design of the analog precoder. To address this issue, we exploit the characteristics of THz massive MIMO communication systems and construct the digital precoder as a product of scale factors and semi-unitary matrices. We utilize Schatten norm and Hölder's inequality to create semi-unitary matrices after initializing the scale factors depending on the power allocation. Finally, the analog precoder and digital precoder are alternately optimized to obtain the ultimate hybrid precoding scheme. Extensive numerical simulations have demonstrated that our proposed algorithm outperforms existing methods in mitigating the beam splitting issue, improving system performance, and exhibiting lower complexity. Furthermore, our approach exhibits a more favorable alignment with practical application requirements, underlying its practicality and efficiency.

• 한국통신학회:학술대회논문집
• /
• 한국통신학회 1987년도 춘계학술발표회 논문집
• /
• pp.223-229
• /
• 1987

The error rate eqations of digital modulated signals transmitted through the fading cdannel have been derived in the Gaussian/Impulsive noise environments Whing the derived equations for the error drobadillties of ASK, QAM, FSK, MSK, PSK, and DPSK signais, the error tate performance of digital modulation systems have been evaluated and represented in the graghes as parameters of carrier to \ulcornernoise power ratio (CNR) and fading figures The results show that in the fading environenet the error is occurred more frequently by gaussian noise in the deep fading Howerer in the shallow fading lmpulsive noise is more domiant than gaussian nosie in occurring the error

• 한국IT서비스학회지
• /
• 제11권4호
• /
• pp.181-194
• /
• 2012

The one of the most meaningful change in the recent ubiquitous environment is the omnipresence of public digital display device for providing ubiquitous information. It is the important issue to provide publicity as well as adaptive information to each user in the field of the public digital display device. This research proposes the idea ensuring fast response speed by the selection of user preference function. The preference function is selected by statistics using Zipf distribution in the system comprising mobile device and digital display device based on NFC (Near Field Communication). The idea is proved by CPM-GOMS model and the improvement of user response can be achieved.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2010년도 추계학술대회
• /
• pp.139-140
• /
• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.

• The Journal of the Acoustical Society of Korea
• /
• 제21권1E호
• /
• pp.18-24
• /
• 2002

This paper discusses the development of an acoustic vector channel simulator for the performance analysis of an acoustic digital communication system. The channel simulator consists of transmission module, acoustic channel model, receiver, beamformer, and adaptive equalizer. The source signal (QPSK) is generated by the specified parameters. The transmitted signal generates multipath signals which have a different delay, amplitude and doppler frequency. The paper presents in details the approach to the performance analysis of an acoustic digital communication system according to the antenna structure and the various baseband signal processing techniques.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
• /
• pp.117-120
• /
• 2009

In this paper, a CR(Cognitive Radio) based on SDR(Software Defined Radio) is the technology combined a method selecting available frequency by recognizing surroundings with a learning algorithm continuously updating basic functions for communication and various environment parameters. Recently, as increasing demands with development of wireless communication service, CR is in the spotlight as technology using frequency resource efficiently. In order to apply CR system to the terminal and implement it, the research field to be preceded can be divided large as a hardware part and a software part. It can be also divided into RF processing and digital signal processing in the hardware part. In this paper, we look over preceding techniques required for applying CR system to the terminal, and research the forms of the terminal when they practically apply to the terminal.

• 한국통신학회논문지
• /
• 제19권7호
• /
• pp.1335-1345
• /
• 1994

대용량 교환시스템인 TDX-10의 내부통신망의 성능을 분석하였다. 내부통신망의 시뮬레이션은 SLAM II의 이산사건모델을 이용하여 개발하였다. 시뮬레이션의 결과로 각 노드에서의 최대버퍼길이와 평균대기시간 그리고 D버스의 이용율을 구하였다. 또한 링크속도를 고려한 내부통신망의 최대호처리용량을 구하였다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제16권2호
• /
• pp.75-80
• /
• 2024

Research on the visual narrative impact of Unreal Engine's Lumen lighting system in games aims to delve into how Lumen's lighting technology plays a crucial role in game design and gameplay experience, thereby enhancing the visual storytelling of games. Lumen, Unreal Engine's dynamic global illumination solution, calculates lighting and shadows in real-time during gameplay, creating a more realistic and immersive environment. Analysis indicates that Lumen technology not only provides visually realistic and dynamic lighting effects but also significantly enriches the expressiveness and immersion of the game narrative through its changes in light and shadow.