• Journal of the Korean Institute of Navigation
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• v.23 no.2
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• pp.61-66
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• 1999

It is being more and more difficult to suppress emissions from electronic products using PCB(Printed Circuit Board) to the limit. Therefore, the exact evaluation of the emission from PCB has been more important to reduce the required time and the cost at the design phase of the products, especially on board ship's equipments. This research has evaluated the emission radiated from PCB based on the theoretical approach of SDA(Spectral Domain Analysis), which is available to analyze microwave stripline, coplanar line, patch antenna, etc. According to the theoretical results, it has been clearly shown that the emission radiated from PCB is reduced as the thickness of PCB is thinner, the permittivity of PCB is higher, the length of stripline is shorter, and the frequency is lower.

• Journal of the Korean Institute of Navigation
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• v.25 no.4
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• pp.335-345
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• 2001

While recognizing that Loran-C is very important as a back-up for satellite systems, the introduction of EUROFIX, that it uses Loran-C system, was proposed and admitted at 9th FERNS(Far East Radio Navigation System) Meeting. But, the FERNS countries should consider whether the cost-effectiveness of the system could be improved by making use of its communication facilities to integrate more closely with satellite systems. And, the members were requested to give this proposal consideration before the l0th session of the Council. or this matter, Korea planned to demonstrate transmitting EUROFIX signals from Pohang Loran-C station (Master of 9930 Chain) during the l0th FERNS Meetings. Therefore, this thesis describes the analysis of EUROFIX datalink and progress of EUROFIX construction work. This thesis is the report with regard to the sequence of this demonstration of EUROFIX in Korea.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.331-333
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• 1999

Power supply for Nuclear Power Plant was developed, and MMI monitoring circuit was added to the main function of power supply. The developed power supply is designed to show equal or higher performance compared with the existing power supplies. Performance of the power supply is verified by simulations, experiments, and authentication test for Q-class, he status of power supply and fault waveform can be displayed and analyzed on PC by RS-232C port. By adopting the latest parts, mainly domestic models, production cost and delivery can be reduced. Replacement period of capacitor can be extended by life estimation.

• Proceedings of the Safety Management and Science Conference
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• 2003.11a
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• pp.297-302
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• 2003

Globalization of Economic activities have increased Company's interests about International Logistics Management. Expansion of International trade depends on International Logistics which can overcome distance and time. In In-cheon, There are many small scale and minor Freight Forwarders take advatage of being linked with a port, an airport but their inefficient paper works cause raising of Logistics costs and losing of competitive power. In this study, we develop a web based ocean forwarder information system for freight forwarder to solve these problems. So, this system will provide decreasing operation time, human resources, and accessing easily because of web based system, and finally decrease logistics cost and improve national competitive power.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.293-298
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• 1997

The H$_{\infty}$robust controller fur the reactor power control system is designed by use of the mixed weight sensitivity. The system is configured into the typical two-port model with which the weight functions are augmented. Since the solution depends on the weighting functions and the problem is of non-convex, the genetic algorithm is used to determine the weighting functions. The cost function applied in the genetic algorithm permits the direct control of the power tracking performances. In addition, the actual operating constraints such as rod velocity and acceleration can be treated as design parameters. Compared with the conventional approach, the controller designed by the genetic algorithm results in the better performances with the realistic constraints. Also, it is found that the genetic algorithm could be used as an effective tool in the robust design. robust design.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.505-508
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• 2000

We discuss simulation results concerning the performance of the TCP protocol when running over high-speed HFC networks. Hybrid Fiber Coaxial are likely to provide fast and cost effective sup-port to a variety of applications including Video on demand, interactive computer games, and internet-type applications such as Webbrowsing, ftp, and telephony. Since most of these applications, use TCP as the transport later protocol, the key to their success largely depends on the effectiveness of the TCP protocol. In all simulation scenarios the TCP traffic is maxed with some background traffic whose level is taken as a variable parameter. Both the background traffic and TCP traffic are either unshaped, or shaped according to the GCRA algorithm. The effect of the background traffic on the TCP protocol performance is discussed varying the buffering capacity with nodes as well as the peak bit rate that each TCP connection is allowed to use.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.4
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• pp.1-12
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• 1994

Most merchant ships are supplied with the only essential fresh water from a port for economical cargo transportation and the reduction of a nevigation expense. And the deficient fresh water for a voyage is produced by fresh water generator with the various exhaust energy generated in the engine room on a voyage. At present, an evaporation type fresh water generator are extensively used on ship because the operating cost of it is lower than that of a reverse osmosis pressure type. This study introduce a development results on the large evaporation type fresh water generator enable to be used for large merchant ships. It is accomplished the performance test using the developed large fresh water generator.

• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.63-76
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• 1999

This paper aims at developing an integrated fleet management support system for industrial carriers who usually control the vessels of their own or on a time charter to minimize the cost of shipping their cargoes. The work is mainly concerned with the operational management problem of the fleet owned by a major oil company, a typical industrial carrier. The optimal fleet management problem for the major oil company can be divided into two phase problem. The front end corresponds to the production operation problem of the transportation of crude oil, the refinery operation, and the distribution of product oil to comply with the demand of the market. The back end is to tackle the fleet scheduling problem to meet the seaborne transportation demand derived from the front end. Relevant optimization models for each phase are proposed and described briefly. Then a user-friendly integrated fleet management support system is built based on the proposed optimization models for both ends under Windows environment. A case study reflecting the practices of fleet management problem for the major oil company is carried out by using the system.

• Journal of the Korean Institute of Navigation
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• v.12 no.3
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• pp.1-21
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• 1988

A Satellite -aided search and rescue system is expected for its many advantage of global coverage, instantaneousness and low cost. In this paper, a calculation method is proposed , by which a position of distress can be determined with doppler frequency received through an orbital satellite. First, an algorithm and program is developed for calculating the position of distress with the received doppler frequency of EPIRB(Emergency Position Indicating Radio Beacon) with the least square method. Then, position error caused by the drift of the transmitting frequency is evaluated. The evaluation is made by the simulation using NNSS satellite orbital elements and varying position of EPIRB, numbers of Doppler data and magnitudes of various errors. As the result, the availability of this program for a satellite-aided search and rescue system is confirmed and the bounds of expected positioning accuracy is clarified.

• 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.