• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.503-507
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• 2007

In this paper, the ultra-widebend, microstrip patch antenna with the bandwidth of 3 GHz was implemented for ultra-wideband(UWB) wireless communication applications. In order to cover the very wide bandwidth of 3 GHz, a multi-resonance antenna was designed, each resonance frequency was separated into five frequency bend, 7.5, 8.1, 8.7, 9.3, and 9.9GHz with the interval of 600MHz BW. And for wideband characteristics of each antenna, U-slot antennas were designed at each center frequency. Designed five U-slot antennas were connected in series for multi-resonance of 3GHz BW and wideband matching was also designed for impedance matching transmission line calculated. The relative dielectric constant, the height, the loss tangent of the PCB substrate were ${\epsilon}_r=4.8,\;h=0.6$ and loss tangent=0.0009 respectively. The implemented antenna's radiation patterns and gain were directivity characteristics and $1.46{\sim}4.08dBi$ at the five separated center frequency.

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.55-74
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• 2020

With globalization and the development of information and communication technology, the supply chain is becoming more widespread and complex, which increases the occurrence and damage caused by supply chain risks. Supply chain risk management has a great impact on corporate performance through the analysis of risk factors and proactive and strategic approaches. This study aims to analyze the effects of supply chain risk factors on risk management strategies and corporate performance empirically. In the research model for empirical analysis, supply chain risk factors were classified into supply, demand, operation, network, and external environment, while the risk management strategies were divided into active and passive strategies, as well as financial and operational performance for corporate performance. The data obtained via the questionnaire were analyzed for the path of the structural equation model. As a result of the analysis, companies are actively pursuing risk management for internal risk factors, rather than external factors, in terms of internal and external risk factors, and it was found that these strategies have a significant effect on corporate performance. Therefore, in the future, companies should conduct risk management strategies more proactively and preemptively through a thorough analysis of various risk factors affecting business operations.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.213-219
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• 2004

In this paper, a LNA(Low Noise Amplifier) has been developed, which is operating at L-band i.e., 1452∼1492 MHz for satellite DAB(Digital Audio Brcadcasting) receiver. The LNA is designed to improve input and output reflection coefficient and VSWR(Voltage Standing Wave Ratio) by balanced amplifier. The LNA consists of low noise amplification stage and gain amplification stage, which make a using of GaAs FET ATF-10136 and VNA-25 respectively, and is fabricated by hybrid method. To supply most suitable voltage and current, active bias circuit is designed Active biasing offers the advantage that variations in $V_P$ and $I_{DSS}$ will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets $V_{gs}$ for the desired drain voltage and drain current. The LNA is fabricated on FR-4 substrate with RF circuit and bias circuit, and integrated in aluminum housing. As a reults, the characteristics of the LNA implemented more than 32 dB in gain. 0.2 dB in gain flatness. lower than 0.95 dB in noise figure, 1.28 and 1.43 each input and output VSWR, and -13 dBm in $P_{1dB}$.

• Journal of Korea Port Economic Association
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• v.24 no.3
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• pp.37-55
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• 2008

This paper attempts to examine the effect of EXPO 2012 Yeosu on the economy of Gwangyang bay area. Based on previous successful EXPOs, We identified four major positive effects (direct economic impact, regional infrastructure developments, redevelopment of slum areas and industrial complex, and internationalization of Gwangyang bay area). Especially, EXPO 2012 Yeosu will contribute to make the job creation of 97,842 employees and promote tourism industry. To maximize the above positive effects of EXPO 2012 Yeosu, we suggest several strategic alternatives in this paper. First of all, we need to make several plans for realizing the specialized theme of EXPO 2012 Yeosu. Second, local governments should create a more favorable business environment for foreign investors. Third, we have to make the strategic tourism programs to attract foreign tourists. Finally, local governments need to make the several communication strategies of utilizing mass media and non-mass media.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.659-666
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• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.

• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.97-102
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• 2003

Wire ropes are used in a myriad of various industrial applications such as elevator, mine hoist, construction machinery, lift, and suspension bridge. Especially, the wire rope of crane is important component to container transfer. If it happens wire rope failures during the operation, it may lead to safety accident, economic loss by productivity decline and so on. To solve this problem, we developed remote wire rope fault detecting system, and this system is consisted of 3 parts that portable fault detecting part, signal processing part and remote monitoring part. All detected signal has external noise or disturbance according to circumstances. So, we applied to discrete wavelet transform to extract a signal from noisy data. It is verified that the detecting system by de-noising has good efficiency for inspecting faults of wire ropes in service. As a result, by developing this system, container terminal could reduce expense because of extension fo wire ropes exchange period and could competitive power. Also, this system is possible to apply in several field such as elevator, lift and so on.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.329-338
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• 2012

The Institute Time Clauses-Hulls 1/10/83 has been using widely with attachment and/or endorsement of the Institute Warranties 1/7/76 stipulating vessel's trading limits. Taking into consideration of several changes and renewals on the contents of the Institute Time Clauses-Hulls for clarifying the clauses themselves with development on technology of vessel's construction and navigational equipments up to the present, the clauses on the Institute Warranties 1/7/76 should have been changed and/or renewed. Moreover, the insured still has been burdening additional premium in vessel's navigating and / or calling to the areas stipulated in the Institute Warranties 1/7/76 regardless of any changes of marine business environments. Thus, this study aims to analyze the Institute Warranties 1/7/76 as well as to suggest a reasonable level of additional premium for breach of Institute warranties through not only a comparative analysis between the Institute Warranties clauses and those of the corresponding Institute Warranties using in the Japanese Fire and Marine Insurance companies but also consideration of current circumstances on changes in climatic conditions, vessel design, navigation and communication requirements and capabilities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.27-28
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• 2011

A solar flares have the 11-year cycle and release a large energy which may produce coronal mass ejections (CME). The NOAA (National Oceanic and Atmospheric Administration) predicted that the sun spot activity will be maximized in 2013-2014. A strong solar flare can cause the disturbance of global positioning system including various communication of TV, radio broadcasting. The actual solar storm in 1989 caused power outages in Canada during 9 hours and about 600 million people had experienced a blackout. Such a solar storm can shorten the GPS satellite's life span about 5 to 10 years which can be resulted in economic loss considering the amount of multi-billion won. This paper analyzed the recent solar storm of X-class occurred on 15th of February about 10:45 this year that was reached Korea (Bohyun observatory) on 18th of February about 10:30 (local time), and compared with the data of before and after a week. The proton data of 18th of February considered that the solar strom reached on earth showed a fluctuation compared to the data of before and after a week. The positioning results at Daejeon also showed higher positioning error compared to the data of before and after a week results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.87-90
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• 2015

Equipments that can transmit maritime distress signals in accordance to Global Maritime Distress Safety System are the followings: A1 water(Very High Frequency, SART), A2 water(MF/HF Radio Equipment), A3 water(INMARSAT), A4 water(Emergency Position Indicating Radio Beacon). Institutions with the capacity to receive distress signals are Korea Coast Guard affiliated radio stations, patrol ships, Rescue Coordination centers, Vessel Traffic centers, Complex problems regarding repetitive distress alarms, inaccurate statistics, multiple control towers are existent. Consequently, effective measurement to resolve dispersed operating maritime distress signal system are in time of need. Moreover, current KCG Headquarter is considering to integrate five distress radio stations dispersed across nation into a single international safety communication center. The integration of radio stations are efficient in terms of information coordination between nations, however, it cannot support efficient response to real-time maritime incident. Therefore, in this study, a new system that can rapidly response to real-time maritime incident will be proposed.

• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.313-346
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• 2011

The Roman thinker, Cicero said, "The Nations that rule the sea, rule the world". In the world history, the countries done critical roles, have emphasized the importance of the sea. The world history is called as the histories of the countries which governed the sea, such as Phoenicia, Greece, Carthago, Roma, Portugal, Spain, England, and USA. The sea is not only the political, economical, social and cultural basis, serving as the origin of resources and channel of communication, logistics and distribution but also the area of dreams and imaginations and ground of potentiality and visions. This paper reviewed the major countries and their histories to realize the vision of Korea, super power country of maritime and fishery. Main maritime policies and its core issues and prospects of Korea were reviewed. And on the basis of these reviews, the vision of super power country of maritime and fishery was suggested. The vision, the 5th super power country of maritime and fishery in 2020, and 10th country of maritime technology level in 2020 and their details were proposed also. For achieving the vision, the resurrection of MOMAF is necessary and its reasons and 5 necessities were suggested. And the directions of the resurrection of MOMAF were proposed in terms of two viewpoints, policy/functional and institutional basis. I think Korea, the super power country of maritime and fishery, can be realized only when MOMAF may be resurrected.