• Title/Summary/Keyword: 디지털해상통신

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Implementation Algorithms and Performance Analysis of Maritime VHF Data System Based on Filtered Multi-Tone Modulation (FMT 변조 기반의 해상 초단파 데이터 시스템의 구현 알고리즘 및 성능분석)

  • Park, Ok-Sun;Ahn, Jae-Min
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.3
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    • pp.254-262
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    • 2013
  • This paper proposes FMT(Filtered Multi-Tone)-based digital radio implementation algorithms and the results obtained by various field tests especially in terms of transmitter characteristics. In this study, we predefined frame structure and protocols used for the CSTDMA(Carrier Sensing Time Division Multiple Access) scheme, designed digital filters and RF front end to fulfill the system characteristics such as the spectral mask and processing delays given by the Recommendation ITU-R M.1842-1. The proposed system supports exchange of data for e-Navigation with the usage of wider channel of 50-100kHz bandwidth, Turbo coding and FMT modulation. Furthermore, the common Ethernet protocol makes connection to local WLAN(Wireless Local Area Network) on board the ship for other data services.

A Study of the Hangul Codes and Algorithm for the NBDP System (NBDP시스템의 한글코드 및 처리 알고리즘 연구)

  • 유형열;조형래;김기문
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.1 no.1
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    • pp.113-121
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    • 1997
  • The maritime mobile communication system has been changing to the new system that is facilitated by the radio telex, digital selective calling and maritime satellite communications from the old system by the radio telegraphy and telephone according to the GMDSS. The NBDP using the ITA No.2 code is a useful media in the maritime communications and provides the procedures of telex. Also it can provide the efficient and more useful functions and the solutions for the incremental traffic requirements by adopting the Hangul code. So, in this paper, we proposed the new Korean NBDP code for the ITA No.2 code, designed and implemented the algorithm which is the processing of the Hangul NBDP code using the microprocessor.

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A study on the radio protocol for ALE of digital communications in HF band (HF대 디지털통신의 ALE를 위한 무선프로토콜 연구)

  • Go, Yun-Gyu;Choi, Jo-Cheon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.811-814
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    • 2009
  • The HF band maritime communication is have developing to digital methode that techniques should be readied the automatic link establishment of 1:N by coast station to many ship station. Because can use way by polling simply that communication environment calls particular station wicked fellow HF communication states which is much redundancy times for coast station to set link. In amateur radio particular station selective calling do to be using ALE(Automatic Link Establishment) controller by 1:1 automatic link setting way, but expect 1:N link setting by these way in maritime communication very difficult. That is difficult to avoid collision by traffic overload to induce calling of ship stations. Because HF communication considers channel special quality traffic state radio link should be established, and should be applied automatically secures stability of channel as accommodative at traffic overload. In this paper is studied the new radio protocol by 3 step sequency driving of free access, group free access and polling access using multi-tone in single channel.

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A Study on the Propagation Environment for VHF Maritime Digital Communications Operation in South Sea Area (남해안의 VHF 해상디지털통신 운용을 위한 전파환경 연구)

  • Ju, Yang-Ro;Kim, Kab-Ki;Choi, Jo-Cheon;Lee, Seong-Ro
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.6
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    • pp.1310-1316
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    • 2014
  • The IMO has recommended on VHF digital communications operation for sailing ships from 2017. And ships more than 5 tons is obliged to digital communications by fishing Vessels Act and Vessel Safety Act in domestic. The owner of all vessel is equipped to the automatic position reporting device in accordance with the Notice of the Ministry of Oceans and Fisheries to regulations, It shall be ensure to navigations safety and in order to respond quickly in the event of maritime accidents on all vessels. The info-communications station of fishery is operating the automatic position reporting system using the VHF DSC in east sea from 2012, Continuously, which is underway the install plan in south sea and yellow sea. But this plan is very difficult, because of propagation environment is poor on account of complicated coastline and many islands. This paper has analyzed the propagation coverage for position setting of coast station in south sea and the traffic zone set up by compare with RSSI and methode of navigation tracking by VMS.

Implementation of π/4-DQPSK Modem for Maritime Digital Communication in VHF Band (VHF 대역 해상 디지털 통신용 π/4-DQPSK 모뎀 구현)

  • Kwak, Jaemin
    • Journal of Advanced Navigation Technology
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    • v.18 no.6
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    • pp.541-545
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    • 2014
  • Rec. ITU-R M.1842-1 is international recommendation for VHF band communication guideline in maritime mobile service RR Appendix 18 channels. In this paper, we simulate 28.8 kbps VHF ${\pi}$/4-DQPSK digital baseband modem compatible with the recommendation, then it is designed and implemented with FPGA. Cazac sequence is used as a preamble since packet format is not defined untill now in the recommendation. Baseband modem is designed by VHDL language and implemented on NEXYS4 development platform having Atrix7 FPGA chip from Xilinx. For wireless communication test of total prototype system, ADC/DAC board is implemented and EV9730 RF module is utilized. From the experimental results, implemented FPGA modem shows spectral bandwidth of 25 kHz and successful data exchanges between tx and rx communication platform.

On Pattern Kernel with Multi-Resolution Architecture for a Lip Print Recognition (구순문 인식을 위한 복수 해상도 시스템의 패턴 커널에 관한 연구)

  • 김진옥;황대준;백경석;정진현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.12A
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    • pp.2067-2073
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    • 2001
  • Biometric systems are forms of technology that use unique human physical characteristics to automatically identify a person. They have sensors to pick up some physical characteristics, convert them into digital patterns, and compare them with patterns stored for individual identification. However, lip-print recognition has been less developed than recognition of other human physical attributes such as the fingerprint, voice patterns, retinal at blood vessel patterns, or the face. The lip print recognition by a CCD camera has the merit of being linked with other recognition systems such as the retinal/iris eye and the face. A new method using multi-resolution architecture is proposed to recognize a lip print from the pattern kernels. A set of pattern kernels is a function of some local lip print masks. This function converts the information from a lip print into digital data. Recognition in the multi-resolution system is more reliable than recognition in the single-resolution system. The multi-resolution architecture allows us to reduce the false recognition rate from 15% to 4.7%. This paper shows that a lip print is sufficiently used by the measurements of biometric systems.

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Design of Coupling and Rectifying Circuit for Monitoring of Transmitting Power of Maritime VHF Modem (해상 VHF 모뎀의 송신전력 모니터링을 위한 결합기 및 정류회로 설계)

  • Kim, Seung-Geun;Sung, So-Young;Lim, Young-Kon;Park, Dong-Kook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.12
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    • pp.2642-2648
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    • 2010
  • The design of coupling and rectifying circuits for the maritime VHF digital modem is investigated in this paper. To monitor the transmitting power of the modem, a directional coupler which is used to extract a small fraction of the transmitter signal power, and a rectifying circuit which make DC voltage proportional to the coupled rf power are designed and fabricated. The parallel-coupled line coupler with directivity of above 25 dB at 160 MHz bands is designed and it is shown that the output voltage of the rectifying circuit is linearly changing from 0.85 V to 1.6 V when the transmitting power of the modem is varying from 1 W to 25 W. The proposed coupler and rectifying circuits are expected to be suitable for maritime VHF digital modem.

Resolution enhancement of 3D images using computational integral imaging reconstruction method based on scale-variant magnification (크기가변 확대 기법 기반의 컴퓨터적 집적 영상 방법을 이용한 3D 영상의 해상도 개선)

  • Shin, Dong-Hak;Yoo, Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.12
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    • pp.2271-2276
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    • 2008
  • In this paper, we propose a computational integral imaging reconstruction (CIIR) method based on scale-cariant magnification technique for resolution-enhanced 3D images. First, we introduce an interference problem among elemental images in CIIR. Magnification by a large factor causes inference among elemental images when they are applied to the superposition process. Thus, the resolution of reconstructed images is limited. To overcome the interference problem, we propose a method to calculate a minimum magnification factor while CIIR is still valid. Magnification by a new factor enables the Proposed method to reconstruct resolution-enhanced images. In addition, the computational load of the proposed method is less than that of the previous method. To confirm the feasibility of the proposed method, some experiments are carried out and the results are presented.

Camera Module for Vehicle Safety (차량 안전용 카메라 모듈)

  • Shin, Seong-Yoon;Cho, Seung-Pyo;Lee, Hyun-Chang;Shin, Kwang-Seong
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2022.07a
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    • pp.633-634
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    • 2022
  • 본 논문에서는 비행 시간 측정(TOF) 센서와 동일한 View로 고정되고 차량의 진행 방향으로 수평 설치 가능한 카메라를 연구 개발한다. 이 카메라는 객체 인식 정확도 향상을 위하여 1,280×720 해상도 적용하고 30fps로 영상을 출력하며 180°이상의 광각 어안렌즈를 적용하는 것이 가능도록 한다.

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HF Data Communication Service Using SSB Modems for Maritime Applications (SSB 모뎀을 이용한 해상용 HF 데이터 통신 서비스)

  • Choo, Young-Yeol;Jung, Da-Un
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.12
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    • pp.2549-2554
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    • 2011
  • This paper describes on development of integrated interface and applications to support stable digital data communication service for small and midium sized crafts exploiting SSB modems and HF wireless sets. Firstly, integrated interface module between GPS (Global Positioning System) and communication devices was developed. Secondly, maritime map was implemented into a display terminal to provide location tracking service and voyage planning function. In addition, condition monitoring service of crafts and fishing report functions as well as alarm functions were developed to support secure fishery. Results of performance measure on developed application services shows that error rate was less than 3% and communication delay was shorter than 1 second when a message length was less than 1 Kbyte along with one-to-many communication type.