• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.746-752
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• 2022

Kiribati, a South Pacific island, and its surrounding countries are gradually submerging to rising sea levels. The sea level continues to change according to the degree of thermal expansion of glaciers and seawater that decreases with increase in temperature. Global warming affects both the amount and volume of seawater, thus increasing sea level. Tidal phenomena occur twice a day to the attraction of celestial bodies such as the moon and the sun. The moon changes the angle of orbiting surface with the Earth equator every 18.6 years, and the magnitude of the tidal force changes depending on the distance between the Earth equator and the moon orbital surface. The University of Hawaii Sea Level Center selected Tarawa, Christmas, Kanton of Kiribati,, Lautoka, Suva of Fiji,Funafuti of Tuvalu, Nuk1u'alofa of Tonga, and Port Vila of Vanuatu. When comparing tide levels for each year for 19 years, the focus was on checking the change in sleep to Tide levels, and rising sea levels was the effect of Tide levels. The highest astronomical tides (HAT) and lowest astronomical tides (LAT) were identified as Tarawa 297.0, 50.8 cm, Christmas 123.8, 19.9 cm, Kanton 173.7, 39.9 cm, Lautoka 240.7, 11.3 cm, Funafuti 328.6, 98.4 cm, Nuk1u'alofa 188.8, 15.5 cm, Port Vila 161.5, -0.5cm, respectively. The Sea level rising speed was Tarawa 3.1 mm/year, Christmas -1.0 mm/year, Kanton 1.6 mm/year, Lautoka 3.1 mm/year, Suva 7.4 mm/year, Funafuti 1.4 mm/year, Nuk1u'alofa 4.2 mm/year, and Port Vila -1.2 mm/year, respectively

• 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.32 no.3
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• pp.67-81
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• 2016

This paper examines the influence of Brexit on container volume of Korea, especially of macroeconomic variables such as exchange rate and industrial production of EU and United Kingdom. To do this, we use monthly time series data during 2000-2016, and introduce the analysis method of cointegration test and VECM, and analyze the influence of industrial production and exchange rate of EU and U.K. on container volume of Korea. The results are as follows. First, the container volume of Korea is influenced by the exchange rate and industrial production of EU in the long run. But the exchange and industrial production of U.K. influenced on only export container volume of Korea, and the influence of U.K. macroeconomic variables on container volume of Korea was not large in the long lun. Second, In the shot run, the influence of exchange rate on container volume of Korea, especially on export container volume was significant in EU and U.K. To sum up, the influence of EU macroeconomic variables on container volume of Korea is larger than that of U.K., and the influence of exchange rate variable is more significant than that of industrial production variable.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.733-739
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• 2007

Demand for Sea & Air intermodal transport has increased between north-China costal cities and Incheon since China's international airline network was not established completely. It will be big opportunity for Incheon to be logistics hub of Sea & Air intermodal transport in the north-east Asia, musing large sea-air cargoes to be transferred at the port of Incheon. Therefore, this study aims to propose competitive strategy on Sea & Air intermodal transport system of Incheon. In this analysis results, this paper shows that sea & air cargoes rather from china to U.S. than from China to Europe is very significant, considering geographically for Incheon and is also devote to not only providing high quality services but also activating RFS(Road Feeder Service) system, enlarging toward Shanghai, Weihai, and Yantai.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.301-306
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• 2014

We proposed a new PCB-type 'common-mode current($I_c$) and differential-mode current($I_d$) detector' working for fast detection of $I_c$ and $I_d$ from the differential-mode signaling, with miniaturization effect and possibility of cheaper fabrication. In order to realize this device, we suggest a branch-line-coupler balun having a composite right- and left-handed(CRLH) one-layer microstrip phase-shifting line as compact as roughly ${\lambda}_g/14$. The presented balun obviously is different from the conventional bent-&-folded delay lines or slits on the ground for coupling the lines on the top and bottom dielectrics. As we connect the suggested balun output ports of the differential-mode signal lines via the through-port named U and coupled-port named L, $I_c$ and $I_d$ will appear at port ${\Delta}$ and port ${\Sigma}$ of the present device, in order. The validity of the design scheme is verified by the circuit-and numerical electromagnetic analyses, and the dispersion curve proving the metamaterial characteristics of the geometry. Besides, the examples of the $I_c$ and $I_d$ indicator are observed as the even and odd modes in differential-mode signal feeding. Also, the proposed device is shown to be very compact, compared with the conventional structure.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.49-57
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• 2002

Including RF Package inductance, substrate coupling through conductive silicon(Si)-substrate is modeled and quantitatively characterized. 2-port substrate coupling model is extended for the characterization of multi-port substrate coupling between digital circuit block and analog/RF circuit block. Furthermore, scalable parameter extraction model is developed. Multi-port substrate coupling can be investigated by linearly superposing a frequency-dependent 2-port substrate coupling model using scalable parameters. In addition, Substrate coupling including RF package inductance effect is quantitatively investigated. It is shown that package effect increases substrate coupling and shifts a characteristic frequencies(i.e., poles) to the higher frequency range. The proposed methodology can be efficiently used to the mixed-signal circuit performance verification.

• Journal of Environmental Health Sciences
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• v.50 no.3
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• pp.169-180
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• 2024

Background: CAPSS missing evaporate emissions of volatile organic compounds (VOCs) from liquid cargo loading and unloading at ports. It needs to be supplemented to improve air quality management and allow more effective policy formulation. Objectives: In this study, the VOC emissions from the loading and unloading of liquid cargo at ports, which are not included in CAPSS, were estimated. The results of this study were compared and analyzed with the emission levels as described by CAPSS, confirming the need for managing VOC emissions from the loading and unloading of liquid cargo. Methods: Methodology provided by the U.S. Environmental Protection Agency (EPA) was applied to estimate the VOC emissions from the loading and unloading of liquid cargo at ports. The types of liquid cargo loaded at unloaded at ports are diverse, but for this study emissions were estimated for 37 VOCs designated by the Ministry of Environment. Results: The estimated results for VOC emissions from liquid cargo loading and unloading at domestic ports was 112,079 tons/yr, which was confirmed to be 11% of the known CAPSS emissions. The highest emissions were found from the loading and unloading of naptha, and the port with the highest emissions was Ulsan Port. Conclusions: The results of the estimated VOC emissions from liquid cargo loading and unloading at ports confirmed the high emission levels. To protect the health of port workers and nearby residents, it is essential to manage the emission sources and undertake continuous research.

• Proceedings of the Korean Information Science Society Conference
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• 2010.11a
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• pp.95-96
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• 2010

• Journal of the Korean Institute of Navigation
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• v.15 no.1
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• pp.95-110
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• 1991

This paper aims to investigated the origins and characteristics of flags of convenience(FOC) with International Ship Register(ISR), which was recently adopted by a few Western Europe countries(for example, Norway, U.K., France) and to compare FOC with ISR in terms of shipping policy, ship management, and expenses, and tax policy.

• The Mathematical Education
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• v.30 no.1
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• pp.59-66
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• 1991

This paper considers the problem of determining how degree examinations' project which consumes a very significant time of the student and his supervisor affect bib overall degree performance and sifts among students of varying performance: particularly at the university level. A survey sampling method for data collection and techniques for analysis are discussed and results show degree project u a poor discriminator.