• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.491-499
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• 2011

Starting with maritime DGPS base stations of Palmido, Ochongdo which have been operated since 1999, truly our nation has become the most powerful country possessed with total of 17 DGNSS base stations in the field of DGNSS operation infrastructure. This paper examines into the country's DGNSS services as measuring the service range of the maritime DGPS base stations in the domestic ferry lines which sections are from Jeju to Incheon, from Busan to Jeju, from Jeju to Nokdong, the propagation characteristics of the radio waves of 300 kHz bands on sea and land path. As a result of identifying the service range of the DGPS in the sea routes of the southern sea and the western sea, the measured results of the DGPS signals are confirmed more than 100 NM(recommended service range). It can be possible to practical use the position information, which is safe navigation and various marine traffic management systems. It will be useful an expansion of maritime DGPS reference station in the near future.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.423-427
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• 2017

The IMO approved e-navigation strategy implementation plan made e-navigation adoption visible. In addition, the schedule for the modernization of GMDSS by the ITU was confirmed at the 4th NCSR meeting. Accordingly, we will complement the existing communication system and provide the requirements for the new communication system to be introduced in the future, reflecting all the requirements for the communication system capable of supporting the e-navigation service. Although the communication method for supporting e-navigation service should be capable of providing IP-based data communication basically, it is impossible to provide internet service because of the narrow-band characteristic in the MF/HF frequency bands. In addition, as the existing GMDSS satellite communication service organization expands and new services are introduced, IP based data communication service will be possible, but service restriction resulting from expensive communication cost can be solved by introducing VSAT service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.529-534
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• 2002

It was recommended for all ship engaged in international voyages to carry the dedicated Digital Selective Calling receiver, DSC equipment, VHF transceiver, etc according to Global Maritime Distress & Safety System. Also International Maritime Organization recommended for navigation and communication equipments to applicate the EMC regulations, therefore most of electronic equipments using in the vessel to be faced with problems to cope with new regulations. This study has applied and analyzed the EMC for an equipment integrated with Ch.70 dedicated DSC receiver, DSC equipment, VHF transceiver and groped for solutions to cope with. The test has applied the electromagnetic interference such as the measurement for unwanted emissions from conductive & radio emission and the electromagnetic susceptibility such as the immunity from voltage, frequency variation and electro static discharge, hence comes to be understand the problems related with the power and the earth.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.603-610
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• 2009

Ice load is one of the important design parameters for the construction of icebreaking vessels. In this paper, the design ice load prediction for the icebreaking vessels under normal operating condition in ice-covered sea is discussed. The ice loads under normal operating condition are expected from sea trials in moderate ice conditions. In this sense the extreme ice loads during heavy ramming or accidental collision are not considered. Current study describes the global ice load on the hull of the icebreaking vessels. Available ice load data from full-scale sea trials are collected and analyzed according to various ship-ice interaction parameters including displacement, stem angle, speed of a ship and flexural strength and thickness of sea ice. The ice load prediction formula is compared with the collected full-scale sea trials data and it shows a good agreement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.58-58
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• 2016

This study aims to enhance Korea's competitiveness by taking the lead in the international standardization and relevant global market. This is to be achieved by performing the role of First Mover through the resolute investment from Fast Follower that is servile to the decision of the organization in the e-Navigation strategy that has been promoted by the IMO. The study methodology is an integrated approach. It is established by modelling LSCM G2B2C2 Platform in maritime safety/security logistics and applied to the enhancement of maritime safety/security in global LSCM. This paper externally contributes to the reduction of world maritime accidents and exalt the national prestige; internally, the enhancement of the national competitiveness through the improvement of shipping port logistics and others. These eventually contribute to Korea's economic development that is combined by both theory and practice and of practical use of the integrated approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1588-1595
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• 2021

Android-based smartphones receive the global navigation satellite system (GNSS) signals to determine their location and provide the GNSS raw measurement to users. The available GNSS signals on the current Android devices are GPS, GLONASS, Galileo, BeiDou, QZSS. This research has analyzed the performance of multi-GNSS position accuracy based on the pseudorange of the smartphone for maritime users. Smartphones capable of receiving dual-frequency are installed on a ship, and multi-GNSS raw information in maritime environment was measured to present the results of comparing the GNSS pseudorange-based dual-frequency positioning performance for each smarphone. Furthermore, we analyzed whether the results of the positioning performance can meet the HEA requirement of IMO for maritime navigation users. As the results of maritime experiment, it was confirmed that in the case of the smartphones supporting the dual-frequency, the position accuracy within 6 meters (95%) could be obtained, and the HEA position accuracy performance within 10 meters (95%) required by IMO could be achieved.

• Asian review of World Histories
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• v.3 no.1
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• pp.59-80
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• 2015

The paper is oriented towards a reflection on the epistemological extension of world history. This discipline is currently opening up for new subjects and new foci of interest, with environmental history being one of them. The paper debates the interaction between the global and the local as one of the main issues of world history. It analyses the impacts of the interconnectivity of diverse regions as well as different geographical and cultural complexes, during the period between 1500 and 1800. Assuming that the sea in its economic, cultural and environmental dimensions contributed actively to world history, and is, in itself, a major factor of globalization, the paper intends to highlight interdependencies which fostered connections between the local and the global. It further submits to discussion which was the impact of an on-going globalization process, based on maritime dynamics, on the environment. Through an analysis centered on the impact of European overseas expansion, some environmental impacts will be analyzed. The paper aims at questioning environmental history as an emergent theme of world history, based on the historical experience of connecting worlds developed in the First Global Age (1500-1800).

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.758-768
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• 2005

The ball screw actuated by the electric motor is widely used as an essential actuator for driving the mechanical system by virtue of accuracy and force transmission capability. In this paper, a design of the global sliding mode control is presented to drive the ball screw actuator along the minimum time trajectory, In the proposed control scheme, if the ranges of parametric uncertainties and torque limits of the system are specified, the arrival time of the load along the minimum time trajectory can be estimated. Also, the arriving time at the reference input and the maximum acceleration are expressed in a closed form solution. Conversely, the capacity of a ball screw actuator including the motor can be easily designed if the external load and its transportation time are specified. The superior performance of the proposed control scheme and analysis is validated by the computer simulation and experiments comparing with other sliding mode controllers.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.82-86
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• 2009

Several damping materials have been employed to reduce the vibration of structures. While it is important to estimate the damping matrix when analyzing damped composite structures using the finite element method (FEM), at present, there is no FEM program that can correctly estimate the damping matrix. In this paper, a new global curve-fitting method is proposed for identifying the system parameters of non-proportional damping structures using a frequency response function. An experimental test for a cantilever beam attached damping material was carried out to verify the performance of the method proposed in this study.

• Strategy21
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• s.37
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• pp.32-64
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• 2015

This paper examines the types and trends of North Korea's military provocations and regional maritime threats against South Korea, and is focusing on the Republic of Korea's naval development and modernizations by the Republic of Korea Navy (ROKN) on future actions, what directions of the ROKN has taken thus far in response, as well as an examination of how the ROKN might respond to vulnerabilities identified throughout modern history. Importantly, this paper does not consider the domestic, bilateral, multilateral, regional and global political dimensions of the situation on the Korean Peninsula; nor does it consider the North Korea's transitional power politics, but including North Korea's nuclear program and submarine-launched ballistic missile developments, as a caveat, this paper is based on open sources in Korean and English language, and thus information concerning provocations is indicative only.