• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.23-30
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• 2014

Recently, Light Emitting Diode(LED) light is changing the light equipment, which was considered just as a power-controlled device in home-network, into a IT convergence device by combining illumination function with wireless communication. As a result, Visible Light Communication(VLC) becomes a more practical solution to ubiquitous networks due to the more spread of LED light. One of representative applications using VLC is a VLC-based indoor navigation system which can provide high-accuracy indoor localization. In this paper, we model and implement a VLC based-indoor navigation system in which a fluorescent light type of LED lamp, which is normally used in large buildings, and smart devices, which are usually used by users, are utilized as main components for indoor navigation. Subsequently, it is expected that the paper can contribute to make VLC applications be more active.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.723-743
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• 2016

Indoor positioning is considered an enabler for a variety of applications, the demand for an indoor positioning service has also been accelerated. That is because that people spend most of their time indoor environment. Meanwhile, the smartphone integrated powerful camera is an efficient platform for navigation and positioning. However, for high accuracy indoor positioning by using a smartphone, there are two constraints that includes: (1) limited computational and memory resources of smartphone; (2) users' moving in large buildings. To address those issues, this paper uses the TC-OFDM for calculating the coarse positioning information includes horizontal and altitude information for assisting smartphone camera-based positioning. Moreover, a unified representation model of image features under variety of scenarios whose name is FAST-SURF is established for computing the fine location. Finally, an optimization marginalized particle filter is proposed for fusing the positioning information from TC-OFDM and images. The experimental result shows that the wide location detection accuracy is 0.823 m (1σ) at horizontal and 0.5 m at vertical. Comparing to the WiFi-based and ibeacon-based positioning methods, our method is powerful while being easy to be deployed and optimized.

• Journal of Navigation and Port Research
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• v.45 no.5
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• pp.231-237
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• 2021

Enhancing the performance of maritime wireless communication has been highlighted by the issue of cell planning in the sea area because of lack of an appropriate Propagation Loss Model (PLM). To resolve the cell planning issue in vast sea areas, it was essential to develop the (PLM) matching the intended sea area. However, there were considerable gaps between the prediction of legacy PLMs and field measurement in propagation loss and there was a need to develop the adjusted PLM (A-PLM). Therefore, cell planning was performed on this adjusted model, including modification of the base station's location, altitude, and antenna azimuth to meet the quality objectives. Furthermore, in order to verify the availability of the cell planning, Communication Service Quality Monitoring System (CS-QMS) was developed in the LTE-Maritime project to collect LTE signal quality information from the onboard equipment at regular intervals and to ensure that the service quality was high enough to satisfy the goals in each designated grid. As a result of verification, the success rate of RSRP was 95.7% for the intensive management zone (IMZ) and 96.4% for the interested zone (IZ), respectively.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.1-8
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• 2013

A signal system for improving the code acquisition complexity of Global Navigation Satellite System (GNSS) receiver is proposed and the receiving correlator scheme is presented accordingly. The proposed signal system is a hierarchical code type with a duplexing configuration which consists of the Zadoff-Chu (ZC) code having a good auto-correlation characteristic and the Pseudo Random Noise (PRN) code for distinguishing satellites. The receiving correlator has the scheme that consists of the primary correlator for the ZC code and the secondary correlator which uses the PRN code for the primary correlation results. The simulation results of code acquisition using the receiving correlator of the proposed signal system show that the proposed signal scheme improves the complexity of GNSS receiver and has the code acquisition performance comparable to the existing GNSS signal system using Coarse/Acquisition (C/A) code.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.512-518
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• 2011

The marine equipment industry in Korea has been growing along with shipbuilding industry since early 1980s. Major shipbuilding might be predicted to shift to China in the near future. Moreover, new paradigm of e-navigation is about to get geared in the real world, which was specifically noted by IMO (International Maritime Organization). In order to catch up with rapid changes in the environments, the industry sector should move fast, the public sector should setup proper measures, and the academic sector should spur the research and development of new technologies. In this paper, international marin equipment markets and standardization trends are presented along with several representative R&D activities.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.207-213
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• 2024

This paper examines the frame boundary detection performance for a satellite navigation augmentation signal orthogonally modulated with Hadamard code to determine the number of message preamble bits. Simulation results show that, even in weak signal environments, designing the message preamble with 32 bits is recommended for achieving stable frame boundary detection.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.155-155
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• 2018

In this study, we measured the communication performance of inductive coupler under high current condition. Ferrite and nanocrystalline cores were used to compare the available PLC communication range and bandwidth for current fluctuations.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.1-8
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• 2007

Loran-C of ground transmitting station base that can prevent confusion of country navigation system and give BACK-UP function about electric wave navigation comparing utilization incapability state about GPS(Global Positioning System) infra that user is spreading rapidly over our society whole such as sea/aviation safety, vehicles navigation, minuteness agriculture, minuteness measurement in this treatise practical use of Loran-C navigation propose. Executed ASF(Additional Secondary Phase Factor) production and an application experiment Loran-C by location error improvement way to enhance practical use value. By the result Loran-C in conclusion that can improve location error 100~400m remarkably by 10~65m reach. Also, production extent is latitude when go composition medium and bends cotton at ASF revision table utilization of land area, this smell is judged to be suitable hardness 10 minutes. And notable location error improvement and numeric of GPS BACK-UP function are judged to be possible at a ASF revision table application to Korea Peninsula whole area hereafter.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.56-62
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• 2006

This thesis researches on the application of computer, modern communication, GIS, GPS, AIS and World-Wide-Web in the field of navigation-aids information system, and has realized an integrated system consisted of navigation-aids information GIS platform, navigation-aids monitoring system and navigation-aids information distribution system. This system has strong integration capability, and has realized navigation-aids information distribution based on WEBGIS at the first time. It strongly promotes navigation-aids daily management and maintenance, and this system provides technique guarantee fur ships and marine departments to acquire navigation-aids information in time, by rule and line expediently.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.361-362
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• 2022

As the importance of maritime communication in a cross-cultural onboard working environment grows, the importance of developing systematic supporting aids both for learning and teaching maritime English has been emphasized. Given that English communication proficiency is one of the most critical factors in determining a seafarer's competency, a systemic supporting system for enhancing maritime English communication capabilities is essential not only for them to professionally carry out and conduct assigned duties onboard, but also for them to navigate success in their lives through increased labour mobility both at sea and onshore. The APEC Seafarers Excellence Network initiates the production of Maritime English Communication Packages for seafarers in APEC regions, under the leadership of the Republic of Korea. This paper introduces the design of APEC SEN Maritime English Communication Packages, which include textbooks, audio-lingual materials, online/mobile life-long learning platform and testing aids, ultimately for upand re-skilling of seafarers to increase their employability, mobility and preparedness for the future shipping industry where globalisation is expected to further accelerate.