• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.243-245
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• 2019

In the VTS, the predictions of vessel mobility and situation awareness of maritime environment are basic function. In recent years, pilotage information is an essential aware element of VTS personnel for vessel traffic management. So, we designed the structure of pilotage information service with VTS and tested in real environment. In the future, similar pilotage information can be used as a useful VTS service.

• Journal of the Korean Institute of Navigation
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• v.24 no.4
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• pp.299-312
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• 2000

Because shore(ship) to ship(shore) communication service via INMARSAT pay expensive cost, satellite service typically use two stage service that land users dial up LES(Land Earth Station) for sending or receiving message. In order to send and receive message, land users must maintain online state with LES on dedicated line. Also, two stage INMARSAT communication service must consume long time that processes step by step. In case of large company, they have own communication system, but small companys communicate simple messages with only telex. This paper describes the design and implementation of an integrated communication services via INMARSAT-C. This system uses inexpensive INMARSAT-C for transmission between ship and land. Because this system provides web and E-Mail interface, users send and receive messages easily and quickly. This system provides most users with inexpensive and easy communication facilities between ship and land.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.129-138
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• 2020

This study recognizes problems in the current system of providing navigation safety information (NSI), which is centered on merchant ships, to prevent maritime accidents of fishing boats and small vessels in coastal areas. The system proposed in this study is an effective method of providing NSI to support the safe navigation of small vessels such as fishing boats. First, the status and characteristics of recent maritime accidents were examined, and NSI service targets were identified. Second, the limitations of the current NSI system were determined, and measures were proposed to establish an NSI Integrated Platform (NSIP) that ensures the integration, accessibility, and usability of NSI for a substantial portion of the public. Third, to utilize the NSIP, various NSIs are applied as additional information for the electronic chart system used in the e-navigation ship terminals being developed in connection with the Korean e-navigation project. Functions that set the audiovisual alarm function to automatically operate when a ship enters a navigation risk zone is proposed. These functions are technically achieved by reviewing expert opinions of related organizations and professional producers. The results of this study suggest that NSI can be applied to small vessels such as fishing boats, through the Korean e-Navigation project, to prevent maritime accidents caused by the human error of navigators.

• Journal of Advanced Navigation Technology
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• v.10 no.1
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• pp.63-69
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• 2006

Recently there are increasing needs for Internet and various kinds of contents. These traffics for various contents need more amount of data to provide high-quality information and require various QoS depending on the characteristics of contents. However, current Internet service supports BE (Best Effort) service only, therefore IntServ (Integrated Service) scheme and DiffServ (Differentiated Service) scheme are represented to support QoS in IP layer. Moreover, while wireless Internet is getting popular, MAC(Medium Access Control) is also becoming important. This is due to the fact that wireless access, resource allocation and packet scheduling, which are done in another layers before, are performed in MAC layer in many new wireless systems. This paper describes new scheme that provides QoS taking into account the traffic characteristics over Mobile IPv6 network based on IEEE 802.11e EDCF and evaluates the performance through computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.542-547
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• 2018

Various countries around the world are conducting various studies to apply information and communication technology to marine safety. Based on this, the International Maritime Organization (IMO) has established the e-Navigation standard to apply the latest information and communication technology to marine services. In Korea, the Ministry of Maritime Affairs and Fisheries is promoting Korean e-navigation considering domestic marine environment and is trying to apply LTE communication method as a high-speed wireless communication method at sea. In this paper, we describe the development of an LTE based marine router system supporting 700Mhz frequency band allocated for high speed maritime wireless communication service. Experiments on the possibility of 100km distance communication from base station using LTE based ship router are shown. LTE - based high - speed maritime wireless communication router system can provide communication infrastructure necessary to develop various accident prevention technologies that may occur at sea.

• Journal of Global Scholars of Marketing Science
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• v.15 no.1
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• pp.21-39
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• 2005

The research objectives of this study were to examine the relationship between e-store attributions(reputation, customer service, safety(security), merchandise quality, information quality, web navigation), trust, satisfaction and web site loyalty. The data were collected using survey with a structured questionnaire. The subjects of the study were 213 people. Several hypotheses were put forward and results except for four hypotheses were supported. That is, reputation, customer service, safety(security) and merchandise quality have a significant influence on trust and satisfaction, information quality and web navigation have no influence on trust and satisfaction, and trust and satisfaction have a significant influence on e-loyalty. Regression Analysis were applied to test the research hypotheses on the relationships among the variables. Research implications of the findings and future research directions are presented.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.146-146
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• 2017

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4287-4306
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• 2016

Network resilience provides an effective way to overcome the problem of network failure and is crucial to Internet protocol (IP) network management. As one of the main challenges in network resilience, recovering from link failure is important to maintain the constancy of packets being transmitted. However, existing failure recovery approaches do not handle the traffic engineering problem (e.g., tuning the routing-protocol parameters to optimize the rerouting traffic flow), which may cause serious congestions. Moreover, as the lack of QoS (quality of service) restrictions may lead to invalid rerouting traffic, the QoS requirements (e.g., bandwidth and delay) should also be taken into account when recovering the failed links. In this paper, we first develop a probabilistically correlated failure model that can accurately reflect the correlation between link failures, with which we can choose reliable backup paths (BPs). Then we construct a mathematical model for the failure recovery problem, which takes maximum rerouting traffic as the optimizing objective and the QoS requirements as the constraints. Moreover, we propose a heuristic algorithm for link failure recovery, which adopts the improved k shortest path algorithm to splice the single BP and supplies more protection resources for the links with higher priority. We also prove the correctness of the proposed algorithm. Moreover, the time and space complexity are also analyzed. Simulation results under NS2 show that the proposed algorithm improves the link failure recovery rate and increases the QoS satisfaction rate significantly.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.82-90
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• 2003

Recently, a new concept of telecommunication system, utilizing stratospheric platforms such as airships or airplanes, has been proposed. This system aims to provide broadband multimedia services, i.e. high-rate multimedia service, high-rate internet service, and leased line service. In this study, operation concept of the system is defined and by allocating required functions on the system and its subsystems, conceptual design of the ground control system for the stratospheric platforms is established and proposed.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.385-390
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• 2016

ELoran Systems can provide Position, Navigation, and Time services with comparable performance to Global Positioning Systems (GPS) as a back up or alternative system. High timing and navigation performance can be achieved by eLoran signals because eLoran receivers use "all-in-view" reception. This incorporates Time of Arrival (TOA) signals from all stations in the service range because each eLoran station is synchronized to Coordinated Universal Time (UTC). Transmission station information and the differential Loran correction data are transmitted via an additional Loran Data Channel (LDC) on the transmitted eLoran signal such that eLoran provides improved Position Navigation and Timing (PNT) over legacy Loran. In this paper, we propose a technique for adapting the delay time compensation values in eLoran timing receivers to provide precise time comparison. For this purpose, we have designed a system that measures time delay from the crossing point of the third cycle extracted from the current transformer at the end point of the transmitter. The receiver delay was measured by connecting an active H-field, an E-field and a passive loop antenna to a commercial eLoran timing receiver. The common-view time transfer technique using the calibrated eLoran timing receiver improved the eLoran transfer time. A eLoran timing receiver calibrated by this method can be utilized in the field for precise time comparison as a GNSS backup.