• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.5-8
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• 2015

Kenya is a sovereign country with a vast potential in maritime industry. Though Kenya is known to have made it in IMO white list on $14^{TH}$ May 2010, she is making huge investments in maritime industry in an effort to have a share of booming world maritime industry and sea trade. Statistics has it that 90% of trade volume is carried on the sea, which is strong indication that for any country inspiring to be an economic powerhouse it has to have a lion share of sea trade volume, and one of the proven ways in gaining economic success is by investing heavily in maritime infrastructure. The purpose of this paper is to give a brief description of marine traffic status in port of Mombasa which is the largest port in Kenya, highlight vital features of multi-billion Lamu port investment under taken by the Kenyan government and finally discuss the future of maritime industry and Kenyan seafarer.

• Proceedings of the IEEK Conference
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• summer
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• pp.23-26
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• 2004

Five-port reflectometer which consists of a ring with 5 arms (two inputs, three outputs) and three RF power detectors has been used as a vector network analyser, a demodulator in the homodyne receiver as well as in Phase Looked Loop (PLL) and so on. Calibration of five-port reflectometer is an important task. In this paper, we present a calibration method of five-port for a propagation channel sounder. The method is based on measurement of the phase differences between the three voltages at the five-port's outputs in order to determine the ratio of two input incident waves. The frequency channel sounder based on five-port is calibrated for each frequency from 2.2 GHz to 2.6 GHz with 1 MHz step. This method can also determine the absolute delays of each propagation path in the propagation channel. The calibration method is validated using measurement data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.110-118
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• 2004

In this paper, a method is presented for the design of an orthomode transducer(OMT) operating at 21/31GHz frequency bands. A square waveguide is used in the common port while the WR-34 standard rectangular waveguide is used in the straight port. The straight port is connected to the common port via a multi-stage quarter-wave impedance transformer. The side port is coupled to the common port through a slot formed along the center line of the common square waveguide. An impedance transformer is employed to match the impedance of the coupling slot with that of the WR-51 waveguide at the output of the side port. Dimensions of the OMT are iteratively optimized employing the theory of waveguide. The validity of the proposed method is verified by fabricating and testing the designed orthomode transducer.

• Journal of Korea Trade
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• v.26 no.2
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• pp.1-20
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• 2022

Purpose - Multiple stakeholders-including politicians, investors, and the wider public-have questioned the value of investing in port infrastructure improvements and the contributions they can make to economic performance. Design/methodology - This paper presents an empirical study of 56 countries with seaports from the year 2006 to 2019 to determine how the quality of port infrastructure affects its contribution in terms of trade openness and economic growth. To this end, this study applies hierarchical multiple regression analysis with panel data to empirically examine the economic impact of port infrastructure quality on the relationship between trade openness and economic growth. After the 56 selected countries were categorized as developed or developing, a multi-group panel data analysis was conducted. Findings - The results of this study show that trade openness has a significant positive effect on the national economy. The findings also indicate that, although developing countries should expect greater economic growth after investing in port infrastructure, this relationship weakens as developing countries become richer. Originality/value - The findings of this study not only elucidate the relationship between trade openness and national economic growth, but they also emphasize the importance of trade openness and port infrastructure in national economic growth, particularly among developing countries.

• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.291-311
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• 2011

The modern ports have become multi-functionalized and network-centralized over time. Recently the development of industry in the land behind the port area has become very important for port itself. Furthermore, the port functions as a finance center and an integrated function of the main bank of the world. It will be necessary for Inchon port to pursue the policy for building itself as a hub center for logistics integration and building network in the region of Northern-East Asia and Seoul Capital City area in order for Inchon port to support and develop various industries through utilizing each aspect of the industrial complex in these areas. By doing this, it will act as a policy for strengthening competiveness for Inchon port. The sharp increase of cargo movement from rapidly developing Industries in China will become a good opportunity for strengthening the competitiveness of Inchon port. However, considering the characteristics of the ports competitiveness, this policy must quickly overcome the difficulties of Inchon port.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.181-187
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• 2010

The performance of underwater wireless communication system is influenced on channel characteristic. Especially, a delay spread cause by reverberation and multi-path happen the ISI (Inter Symbol Interference) and reduces the communication performance. In this paper, we study the application of high speed data transmission in underwater to use the OFDM (Orthogonal Frequency Division Multiplexing) technique for robust the reverberation and multi-path. we confirm the performance of communication in underwater to use the model for actually underwater channel simulation model. As a result, we acquired the BER of modulation techniques. The BER of single carrier is $2{\times}10^{-1}$ and BER of multi carrier is $8{\times}10^{-2}$ in 1000m.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1178-1189
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• 2015

A non-isolated Multiple Input Converter (MIC) with an input port, two storage ports and a load port is proposed. The synthesis of the proposed four port converter with its switch realization is presented. A steady state analysis of each operating mode with a small-signal model is derived, and a stability analysis is done. A mode selection controller is proposed to automatically choose a specific operating mode based on the voltage levels of the different source and storage units. In addition, a voltage control loop is used to regulate the output voltage. A 200W prototype is built with a TMS320F28027 DSP controller to test the feasibility of the operating modes. Simulation and experimental results show the ability of the proposed converter to handle multiple inputs either individually or simultaneously.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.137-138
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• 2006

In this paper, we study the algorithm for the multiport measurements using the 2port VNA(Vector network Analyzer). We explain the conversion algorithm which the open impedance to the matched impedance(50 ohm), and then we apply this algorithm to the 4 port VNA measurement. Finally, we discuss the reliability of this algorithm.

• Journal of Biomedical Engineering Research
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• v.14 no.4
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• pp.327-332
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• 1993

Automatic transmission of data from the blood analyzer to the request site is one of the most important part in hospital computerization. We have developed a system that transmits data from the arterial blood gas analyzer to the request site automatically In this system HOST computer, FILE server,'LAN(Local Area Network) , 3270 Emulator and bfulti-port card are integrated with 3 blood gas analyzers(NOVA Inc., USA) which are connected to a single multi-port card in a personal computer. When specimen are collected from tramp)inly sites, they are transferee to the laboratory In the Yonsei Cardiovascular Center After analysis, the result is transmitted to the personal computer via serial commnunication between machine and multi-port card using interrupt method. Then, the patient's information (Name, Patient ID No., etc.) is obtained from the HOST computer througth the emulator. The combined data (patient information & lab data) is transmitted to each request site via LAN automatically These results are stored in the File Server for one year and they can be reviewed anytime. Also, it could be used for the various statistics and the flow chart for clinical research. Additionally, we found thal this system reduces the personal labor.

• Korea Trade Review
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• v.42 no.1
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• pp.283-301
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• 2017

As a consequence of the changed role and functions in port operations, the role of port hinterland has transformed to multi-functional logistic centre linking more efficiently elements of the supply chain. This paper analysed distribution centre selection factors in Busan new port hinterland, aiming to diagnose and evaluate the operational situations of port hinterland as multi-functional logistics centre. Based on a data collected from all 122 samples located in Busan new port hinterland, determinants for location competitiveness identified were: political support, market potentiality, infrastructure utilization, market niche, and connectivity. Comparing the difference between an importance and performance, it is revealed that the target port hinterland requires urgent improvement in political supports such as incentive programmes offered by host country, free trade system and related law, financial assistance in constructing distribution centers, and simplicity, ease and efficiency of administrative procedures. The results provide useful insights for establishing future improvement strategies and a strategic agenda to successfully respond to the demands of the companies located in port hinterlands and/or new customers those who want to move in.