• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.23-28
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• 2009

The general six-port phase correlator is comprised of a Wilkinson power divider and three $90^{\circ}$ hybrid coupler, which has less than 10 % bandwidth. In this paper, the six-port phase correlator using two section power divider has 33 % bandwidth and external matching $90^{\circ}$ hybrid coupler with 15 % bandwidth was designed at the center frequency of 2.5 GHz. The simulation result by ADS2003A indicates that RF port and LO port of proposed six-port phase correlator got wide frequency bandwidth of 14 % for VSWR of 1.5. The fabricated six-port phase correlator has a bandwidth of 12 % similar to the simulation result. The maximum phase discrepancy and insertion loss are $6^{\circ}$ and 2.5 dB over a bandwidth, respectively.

• Journal of Coastal Disaster Prevention
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• v.4 no.1
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• pp.1-6
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• 2017

Most of the short period waves are blocked by the breakwaters when the short period irregular waves propagate into the ports. However, nonlinear irregular wave numerical experiments show that the long waves generated by the nonlinear interaction is predominant in the port. Seiches phenomenon in Geumjin Fishing Port is very similar to 60 and 300 second harbor oscillations. By arranging the inner breakwater of the proper length in the inside of the port, it is possible to effectively reduce seiches, as well as the short-period wave, and significantly improve the harbor tranquility. In the case of rectangular basin type such as the Geumjin Fishing Port, the multi-directional irregular wave numerical model should be used for the investigation and countermeasures for the harbor tranquility.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.543-558
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• 2012

Purpose: The purpose of this study was to propose useful suggestions by analyzing causal effect relationship between port service quality, and customer satisfaction and performance in port industry. Methods: The collected data through the survey were analyzed using multi-regression analysis. The measurement tools used for this study were divided into three dimensions such as internal quality, interaction quality and environmental quality. Results: The results of this study are as follows; regarding the influence of pot service quality dimension on customer satisfaction, it was found that the effects of interaction quality and internal quality were significant and those of environmental quality was not significant on customer satisfaction. It was found that customer satisfaction made statistically significant influence on performance from the investigation of the causal effect relationship between customer satisfaction and performance. Conclusion: Incheon Port needs to act actively paying attention to port facilities, efficient operation, network, cargo recruitment activities, smooth communication and fast handling.

• Electrical & Electronic Materials
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• v.21 no.8
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• pp.3-10
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• 2008

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.690-693
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• 1995

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.41-46
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• 2004

In this paper, we study the stabilization control if an underwater vehicle from its initial posture to its desired one. We assume tint the underwater vehicle has velocity constraint, i.e. it has no velocity component for some direction. Our approach is based on the nonholonomic system which am derived from velocity constraints that cannot integrable. We proposed a control strategy for posture control of the underwater vehicle using multi-rate digital control. The proposed control scheme is applied to the berthing control if an underwater vehicle and verified the effectiveness if control strategy by numerical simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1313-1318
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• 2011

This paper proposes a protocol integration system with multi-threading method for the ship electronic devices to solve problems with the compatibility. The proposed protocol integration system receives the different signals from each of the ships' devices through the RS-232 serial communication port and then divides the input signal into the field data. The required field data for standard signal composition are extracted from among these signal and these are combined in accordance with standard signal format. Thereafter, the protocol integration system transmits the processed standard signal to the auto pilot system through a single port.

• Particle and aerosol research
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• v.9 no.3
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• pp.133-137
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• 2013

Measuring particle size distribution is one of the primary concerns in aerosol studies. For a nano-particle size distribution measurement, many scientists use a combination of a differential mobility analyzer (DMA) and a condensation particle counter (CPC) system, which is a called scanning mobility particle sizer (SMPS). Although it has a very high particle size resolution, some issues still remain. These problems include residence time between a DMA and a CPC, discontinuity of a CPC, and disturbance due to long scanning time during the precise measurement of particles. In particular, long scanning time is not adequate for measuring particle size distribution since the particle concentration is changing during the measurement. In this study, we developed radial exhaust multi-port system (REM-system) with no scanning time and high resolution to measure real-time particle size distribution. As a result of the REM-system performed using mono-disperse particle, it is expected that this system will be suitable for measuring continuously changing aerosol. If the counting efficiency of multi-condensation particle counter (M-CPC) and data inversion matrix are completed, REM-system will be a very adequate system for unsteady aerosol, which changes for SMPS scanning time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1164-1170
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• 2002

In the ACE2000 MPLS system, MPLS Interface Module(MIM) is composed of an ATM Interface Module and a HFMA performing a packet forwarding. In the MIM, the HFMA RSAR receive cells from the Physical layer and reassemble the cells. And the IP Lookup controller perform a packet forwarding after packet classification. Forwarded packet is segmented into cells in the HFMA TSAR and transfer to the ALMA for the transmission to an ATM cell switch. When the MIM make use of an ATM Interface Module, it directly connect the ALMA with a PHY layer using the UTOPIA Level2 interface. Then, an ALMA performs Master Mode. Also, the HFMA TSAR performs the Master Mode in the MIM. Therefore, the UTOPIA-L2 Controller of the Slave Mode require for interfacing between an ALMA and a HFHA TSAR. In this paper, we implement the architecture and cell control mechanism for the UTOPIA-L2 Controller supporting Multi-ports.

• Journal of the Korean Institute of Navigation
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• v.13 no.3
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• pp.37-44
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• 1989

Recently recognize the labor productivity of port physical distribution system in the port and shipping areas, Much Efforts for evaluating this productivity has been made continuously. BUt still there is little study, so far, on a systematic research for the management of port labor gangs, and even those were mainly depended on a rule of thumb. Especially the object of this study is to introduce the method of optimal allocation and assignment for the labor gangs per pier unit in the multiple ships berthed at an arbitary pier or port. In case the multiple ships have a homogeneous cargoes or do not have sufficient labor gangs to be assigned. The problem of optimal allocation and assignment of the labor gangs to be i) formalized with multi-state decision process in form of difference equation as the pattern which converted the independent multiple ships into a single ship with the intra-multiple ships, and ii) the optimal size of labor gangs could be obtained through the simple mathematical method instead of complicated dynamic programming, and iii) In case of shortage of labor gangs available the evaluation function considering the labor gangs available and total shift times was introduced, and iv) the optimal allocation and assignment of labor gangs was dealt at the point of minimizing the summation of the total shift times and at the point of minimizing the total cost charged for the extra waiting time except PHI time during port times for the multiple ships combinations.