• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.217-221
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• 2003

In this work, we used a novel RF-CSP to develop a broadband amplifier MMIC, including all the matching and biasing components, for Ku and K band applications. By utilizing an ACF for the RF-CSP, the fabrication process for the packaged amplifier MMIC could be simplified and made cost effective. STO (SrTiO$_3$) capacitors were employed to integrate the DC biasing components on the MMIC. A pre-matching technique was used for the gate input and drain output of the FETs to achieve a broadband design for the amplifier MMIC. The amplifier CSP MMIC exhibited good RF performance (Gain of 12.5$\pm$1.5 dB, return loss less than -6 dB, PldB of 18.5$\pm$1.5 dBm) over a wide frequency range. This work is the first report of a fully integrated CSP amplifier MMIC successfully operating in the Ku/K band.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.166-175
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• 2006

Since many years ago and in spite of the existence of national regulations and international conventions ratified by the countries that are conformed the Central American Region (CAR), the seagoing maritime sector of this Region, has developed its activity without any type of safety measures. Therefore, a large number of people are known to die, disappear and suffer from serious injuries each year. These maritime casualties devastate the families affected by these events, and severely impact the local social and economic well-being. While all these accidents occurred in this Region, non government or any other official records are available recording these casualties Due to the lack of any historical written reports about maritime casualties occurred in this Region, the compilation of this type of accidents information and data was carried out directly by the researchers in the field. Also, all the information about the CAR Maritime Organization Components was too compiled by the authors from the respective National Maritimes Authorities. From the compiled information was elaborated the CAR maritime casualties data base and from the analysis of the above data base were determined the main causes of the maritime accidents occurred in the CAR. The lack of safety measures onboard and the ignorance of the presence and influence of atmospheric phenomena were among main factors that had been caused the maritime casualties in this Region. By other hand, from the analysis of the CAR maritime organization components, the existence of one level of organization very similar among them was determinate. The objective of this research was to analyze the role of the CAR maritime organization in the prevention of the occurrence of maritime casualties. The results of this study provides general understanding of the causes of this type of accidents in the CAR and basis for support in improving safety navigation system and measures so that the number of fatalities and maritime accidents may be reduced in the future.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.105-124
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• 2018

The purpose of this study is to identify human factors that directly or indirectly cause ship accidents and to suggest implications based on the derived human factors. In particular, we conducted a survey on the basis of the human factors derived from the literature survey and interviews, and applied the revised importance-performance analysis (IPA) to develop implications from a comparison of two groups: seafarers and shipping operations managers. Data were collected from 159 practitioners in the Korean shipping industry. The analysis structure consisted of five major factors with 20 components, including unique factors related to ship and shipping management companies, personal competence, in-vessel organization, and personnel's health, as well as social factors. The result of the IPA analysis indicates that in-vessel organization is the most urgent and major factor for improvement. Some differences exist in the components that should be improved between the two groups. For the seafarer group, an increase in unskilled onboard crew affected sustainable safety activities, thus implying an area of preferential improvement regarding the in-vessel organization factor. However, for the shipping operations managers group, the difference in recognizing safety standards among the crew members on board and the ability to communicate with other crew members should be improved first relative to in-vessel organization factors. The personnel's health factor was identified to be of low importance in both groups. Finally, the importance of improving the safety consciousness level according to the safety education and training implementation for seafarers on board was different for the two groups.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.321-338
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• 2009

This study looks at the reasons behind the termination of container transportation between Busan and Incheon in terms of costs structure, the division of profit, and the economic limitation faced in the domestic shipping market. The operation costs have been examined in relation to the components of logistic system of container shipping and the cost function has been estimated. The distribution proportion of operation revenue has been also investigated, considering the different components of logistics activities. In addition, the average revenue of container vessels of 144TEU and 215TEU has been calculated. Economic limitation can be analysed through the optimisation behaviour of shipping companies which tries to maximize profit or minimize loss. In conclusion, domestic short sea shipping can get the economy of scale only by transporting vessels' maximum capacity. It is also vulnerable to trucking market's fluctuation. Without the subsidy for operation, the liner in domestic short sea shipping will stop the service in order to minimize the loss.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.279-290
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• 2000

The purpose of this study is to suggest the analytical framework for a spatial structure of a tourism destination master plan by the two types of the tourism development models: Tourist attraction System Model and Tourism Destination Region Design Model. The resort development plan is introduced as a planning tool for regenerating the eastern Pusan regions, but the economic and environmental impacts and the sociocultural dilemma accompanied by the development should be fully considered before launching the business. The development plan announced currently is traced and examined in comparison with the upper-leveled and related plans. The Tourist Attraction System Model based on the systems theory is applied to the designated regions. The Tourism Destination Region Design Model then is applied for analyzing the components of each region on the master plan. The results of the findings suggest that the tourism destination plan is basically different from a general master plan on the physical comprehensive plan, the destination is recognized as a subsystem of the whole tourism system, and thus tourism destination plan is considered as a spatial arrangement of tourism facilities and the inter- and intra-circulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.40-44
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• 2000

In this paper, since the research on the etching of SrBi$_2$Ta$_2$O$_{9}$ (SBT) thin film was few (specially Cl$_2$-base ), we had studied the surface reaction of SBT thin films using the OES in high density plasma etching as a function of rf power, dc bias voltage, and Cl$_2$/(C1$_2$+Ar) gas mixing ratio. It had been found that the etch rate of SBT thin films appeared to be more affected by the physical sputtering between Ar ions and surface of the SBT compared to the chemical reaction in our previous papers$^{1.2}$ . The change of Cl radical density that is measured by the OES as a function of gas combination showed the change of the etch rate of SBT thin films. Therefore, the chemical reactions between Cl radical in plasma and components of the SBT enhance to increase the etch rates of SBT thin films and these results were confirmed by XPS analysis.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.25-26
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• 2007

Ship are typically thin-walled structures and consists of stiffened plate structure by purpose of required design load and weight reduction etc. Also, a hull structural characteristics are often used in structures with curvature at deck plating with camber, side shell plating at fore and aft parts and bilge circle parts, It have been believed that these structures can be modelled fundamentally by a part of cylinder. Structural component with curvature subjected to combined loading regimes and complex boundary conditions, which can potentially collapse due to buckling. Hence, for more rational and safe design of ship structures, it is crucial importance to better understand the interaction relationship of the buckling and ultimate strength for cylindrically curved plate under these load components. In this study, the ultimate strength characteristic of curved plate under combined load(lateral pressure load + axial compressive load) are investigated through using FEM series analysis with varying geometric panel properties.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.60-62
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• 2015

Dynamic Positioning System(DPS)은 동력, DP control 장치, DP 컴퓨터, 위치참조시스템(PRS), 센서, thruster 시스템 및 DP 운용자(DPO) 7가지로 구성되어 있다. DP 선박은 이들 구성요소들에 문제가 발생하면 그 기능을 상실할 수 있다. 본 연구에서는 2001~2010년까지 10년 동안 IMCA 보고된 DP 선박 관련사고 612건에 대한 분석을 바탕으로 DPS의 7가지 구성요소와 관련된 사고 원인을 파악하고 이들 중 가장 높은 비율을 차지하는 원인을 정성적, 정량적으로 상세 분석하여 요소별 관계와 주요 작용 요소를 확인하고자 한다. 이를 통해 DP 선박의 LOP사과 관련 분석에 있어 베이지안 네트워크의 활용성을 확인해 보았다. 10년 평균 가장 높은 비율을 차지한 DPS 사고원인 요인은 PRS이었으며 이를 전문가 브레인스토밍을 통해 작성된 flowchart를 바탕으로 베이지안 네트워크를 통해 상세 분석해 본 결과 PRS의 각 요소별 조건부 확률 확인할 수 있었다. DP 선박의 drive off를 발생시키는데 주요한 영향을 미치는 것은 DGPS, microwave radar 및 HPR 이었고 DGPS에 주요한 영향을 미치는 에러 요인은 signal blocked, electric components failure, relative mode error 및 signal weak or fail 이었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.964-973
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• 2017

In this paper, we analyze the effects of parasitic components of common-mode choke on the common mode and differential mode in a wide band, and we propose a simple method for high-frequency modeling. Common mode and differential mode 2-port networks were configured and the S-parameters in each mode were measured using a network analyzer. Equivalent circuit elements were extracted from the measured results to model a high-frequency equivalent circuit, and the validity was verified by comparing the measured S-parameters with the simulation results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.725-730
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• 1987

An experimental study of the air flow through inlet pipe of reciprocating two-cycle engine was investigated under motored condition. Measurements of the two components of velocity, velocity fluctuation, and the other behavior of inlet flow have been obtained by laser Doppler anemometer system. The research engine comprised the cylinder head of a two-cycle engine which mounted on optical spacer with measuring window and glass inlet entry for laser anemometer measurement. A dual beam laser Doppler anemometer was used with conventional forward scattered method and comprised argon-ion laser, frequency shifter with Bragg cell module, and the signal processor. Measurements of mean velocity fluctuation of inlet flow for different engine speeds, measuring positions, and the changes in cylinder volume are investigated. The results presented show that the changes in engine speed is shown to be strongly influenced on the mean velocity of inlet air. The effect of measuring position and cylinder volume on the inlet velocity was also investigated for the inlet port entry and is shown to be small compared to the engine speed.