• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.667-674
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• 2011

Data networks at sea will be overlapped networks with not only traditional carriers such as RF, satellites but also BWA like wireless LAN, WiBro, and WCDMA in near future. In this paper, an overlapped MANET model for data networks at sea, and a routing protocol (OMH-MW) selecting optimal transmission medium for each hop in routes are proposed. OMH-MW measures the optimality of each medium regarding the transmission characteristics of each application and those of the medium in together. The most suitable medium to each link is selected as the link in routes. Performances are compared with those of the MWR (Max-Win based Routing protocol searching optimal routes with only one medium).

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.744-753
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• 2015

This paper presents the results of research on developing marine unified communications to provide VoIP service based on marine satellites. With the recent popularity of smart-phones and other mobile devices, the demand for Internet-based wired and wireless unified technology has been growing in marine environments, and increasing interest is being directed to VoIP products and service models with high price competitiveness and the ability to deliver a variety of services. In this regard, this research designed three instruments, developed their unit modules, and verified their performances. These three instruments included the following: (1) a marine VoIP module equipped with an analogue gateway that can be linked to the existing devices used in vessels, which is more than 80% smaller than that of a land system; (2) a text/voice/video engine for marine satellite communications that runs on technology that minimizes communication data usage, which is a core technology for a marine VoIP service; and (3) a unified communication service that can support multilateral cloud-based message conversations, telephone number-based call functions, and voice/video calling between a private space in a ship and shore.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.183-186
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• 2010

This paper presents a stable real-time based FlexRay technology which is employed with a standard protocol of the marine electronic equipments and the bridge navigational watch alarm system (BNWAS). The traditional marine communications use NMEA communication protocols, and RS-232 and RS-422 techniques in the BNWAS, thus there are difficulty in seeking stability and reliability. To overcome such problems we utilize the FlexRay protocol technique to prevent data loss or error.

• Journal of Korea Multimedia Society
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• v.16 no.12
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• pp.1403-1412
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• 2013

In the maritime ships or airplanes, users should utilize the satellite channel in orer to use web service. However, the satellite channel is costly and does not give users satisfied response time. In the ship, the users may receive plenty of extra data when they obtain internet news. The extra data may be unnecessary image and advertise. Therefore, they should pay unnecessary data usage charges as well. In this paper, we suggest a proxy model that solves the problem of cost and speed. The proposed proxy reduces the of data through the satellite link by image and advertising blocking, caching, image re-requesting functions. It's performance was tested by a real satellite communication.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.354-362
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• 2015

In this study, for integrated management and inter-exchange of operational data generated by ships and land-side information on safe and business, a vessel communication system with modular functions was designed that applied high efficiency compression, least-cost algorithms and Inmarsat FBB connection automation system. Performance test at the KTsat Kumsan satellite earth station; system was found to delivered an average transfer speed of 7 kB/S, which was significant improvement from the existing commercial product's average speed of 5 kB/S. It also delivered twice the efficiency of the existing product in terms of compression rate and transfer of the most widely used office files in maritime businesses.

• Journal of Navigation and Port Research
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• v.35 no.10
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• pp.811-816
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• 2011

In this paper, we analysis to consider the performance of PSPM (Phase Shift Pulse-position Modulation), the one of the low power communication technique, in near-field underwater sound channel by sea trial. PSPM is a QPSK(Quadrature Phase Shift Keying) modulation combined with PPM(Pulse Position Modulation) for low power communication in WBAN(Wireless Body Area Network). It is known that the bandwidth efficiency of PSPM is lower than conventional PSK but the power efficiency increases. In this paper, we will analyze the BER performance of PSPM using data acquired from the sea trials. The BER of QPSK was $6.04{\times}10^{-2}$, PSPM was $3.5{\times}10^{-1}$. Also, PSNR of QPSK was 9.37 dB and in case of PSPM was 9.11 dB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.428-433
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• 1998

국제적으로 개발되고 있는 전자해도는 선박의 대형화 고속화로 인한 각종해난사고의 예방과 급증하는 해상교통을 효율적으로 처리하기 위한 안전항해시스템의 기본데이터로 사용된다. 국제기구인 IHO는 1996년에 전자해도관련 국제표준을 제정하고 각 회원국에 전자해도 개발을 강력히 권고하였으며 이에 따라 국내에서도 국립해양조사원이 1999년 완료를 목표로 전자해도 개발을 추진하고 있다. 전자해도의 개발과정은 기존의 종이해도를 디지틀화 하는 것에서 출발하며 이 과정에서 CIS를 이용한다. 국내에서는 수로데이터의 처리에 강력한 기능을 갖고 있는 CARIS를 사용하여 수치해도를 제작하고 이 데이터를 기본으로 전자해도 데이터를 생성한다. 실제로 종이해도를 스캔한 이미지 파일을 벡터화하고 각종 관련 규약에 맞게 편집하여 수치해도를 제작하며 이를 바탕으로 S-57 기반의 전자해도를 제작한다. 이 과정에서 CARIS는 이미지의 벡터화, 각종 심볼의 입력, 좌표변환, 오브젝트의 입력ㆍ수정등을 수행한다. 본 논문에서는 KRISO가 1995년 말부터 국립해양조사원에서 위탁받아 연구한 전자해도 개발과정과 검수과정을 소개하고 그 과정에서 사용된 CARIS의 활용에 대해 설명한다. 이러한 고찰을 통해 향후 중요하계 다루어질 전자해도의 공급 및 관리시스템의 GIS 활용을 고려할 수 있을 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.252-255
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• 2005

In this paper, we analysed the new techniques for maritime mobile communications replacing NBDP in MF/HF bandwidth. Several countries already have contributed to new proposals for new digital systems through international standardization organizations as ITU, IMO and IEC. ITU-R SG8B in ITU reviews the contributed documents and discusses about radio regulations relating new systems. Also COMSAR in IMO reviews member's countries opinions and statues for introducing new techniques and replacing NBDP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.990-998
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• 2008

In this paper we achieve experimental data evaluation using SSB(Single-side band) modulation in the ocean. Present research in underwater communication is applying digital modulation, OFDM and MIMO system. However, Commercial modems using analog modulation techniques in oceans. So, we achieved experimental for modem appliance development of correct high quality in South Korea sea characteristics. This experimets achievd useing SSB analog modulation in Jin-hae shore of shallow water condition. Used data are tonal and LFM signal for getting underwater channel characterisitcs and female Korean speech for speech communications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1990-1998
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• 2017

The success of naval operation prioritizes the implementation of a robust communication network that delivers accurate and prompt communications to one another. The satellite, which is the main communication network of the military, is required to construct a preliminary communication network because of the enemy radio disturbance and weak point of fixed antenna. The military operational communication network has been in transition from voice-centered wireless communication network to text message-based communication network. In this paper we suggest an enhanced communication method built on Roll Call, the main communication method of ROK Navy operating tactical data link called Link-11. Simulation results display that the proposed method reduces the transmission time per unit frame by 4.3 times compared to the Roll Call and 6.3 times compared with the Round Robin & Broadcasting; it is also proved that the higher the direct reception rate, the shorter the transmission time required by 1.6 times maximum.