• Journal of Navigation and Port Research
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• v.40 no.5
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• pp.345-351
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• 2016

This study presents a system dynamics methodology to evaluate quantitatively the effect of the Korean government's development policy, such as tax reductions, on the industrial economy. System dynamics is often perceived as an optimized means to identify the dynamic inter-relationships among various factors of development policies, and in particular the industrial characteristics and uncertainties of the coastal shipping industry. The results of simulations used in this study shows that the impact of development policies such as tax reductions would increase shipping demand for about 4 years, and that tax incentives could raise the demand volume for cabotage cargo from 5.26 to 11.11%, through the available freight-down by 90~95% points. The system dynamics approach used in this paper represents an initial attempt to use this methodology in studies of the coastal shipping industry. On the basis of our simulations, the industrial effects of other development policies, such as ship financing support, investment of social overhead, or crew supply, could also be analyzed effectively. Additionally, it should be possible to extend these results by developing a comprehensive model encompassing these various analyses.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.397-403
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• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.51
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• pp.263-283
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• 2011

There are two typical international rules in issuing guarantee for obligations of party which is responsible to provide some duties such as services, construction, plants, loan repayment, etc. The two internationally recognized rules are currently ISP98 and URDG758. ISP98 was firstly introduced in 1998 for American banks to issue standby letter of credit domestic and overseas for the area where UCP does not cover. URDG was introduced first in 1991 in the name of URDG458 but it has not been widely used and therefore new URDG named URDG758 came out in 2010 to accommodate more standard guarantee practice. At the face of these two prevailing international rules, the users are sometimes confused which rule would be more suitable for their individual transaction. This led us to conduct a comparative analysis on these two rules. Our study suggests that URDG758 is more adequate for construction, ship-building and plants-supply obligations whilst ISP98 is for financial obligations. Also attentions are required when issues such as counter guarantee, governing rule, presentation period, document examination period and default statement exist. This is because ISP98 and URDG758 have different view points.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.46
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• pp.159-177
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• 2010

This work intends to study some problems in relation to the issuance of letters of credit. Those problems are the delay of issuing letters of credit, the reissuing letters of credit, and the issuing letters of credit in the third party's name. Sellers and buyers must keep in mind that the supply of letter of credit by buyer is the condition precedent for a seller's shipment obligation. A seller has no obligation to ship the goods until he receives the letter of credit by buyer's bank, issuing bank. An issuing bank can have the risk that an original letter of credit and a reissued letter of credit can be used double in the exporting country. The most safe method for issuing bank is to cancel the original letter of credit and to reissue a new letter of credit. When an issuing bank issues a letter of credit in the third party's name, the bank should investigate the background of the transaction and give the buyer a proper line of credit.

• KIEAE Journal
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• v.10 no.4
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• pp.87-100
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• 2010

The energy efficient design of the multiple stock housing is very important not only to save energy but also to increase sustainability in a whole city because the multiple stock housing type is dominated in the major residential supply markets in Korea. During the early design phase of the multiple stock housing type, the architect need convenient and accurate tools for evaluating energy consumptions based on building types rapidly. Building Information Modeling(BIM) is introduced as useful tool systems providing interoperability between 3rd dimensional modeling tools and environmental engineering analysis tools, and could reduce time and cost for unnecessary modeling works in the analysis. However, it is still hard to apply to building design practice and integrated energy simulation techniques because interoperability using industrial standard file formats such as IFC and bXML is still underdeveloped. Therefore, the purpose of this study is to perform the building energy simulations, to compare the results on typical building types in multiple stock housing based on BIM, and to clear the problems using industrial standard file formats between 3rd dimensional modeling and building energy simulation software. In addition, through comparisons with simulation results according to the typical building types such as building forms, orientations, and building stories, the interrelation ship and characteristics of BIM based building energy simulation software are analysed and evaluated.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.56-64
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• 2004

Several types of steel structures which are employed in offshore petroleum activities are constructed with tubular members. These structures are usually subjected to various types of loads such as normal functional loads and environmental loads. Furthermore, accidental loads may also act on the leg or bracing members due to supply boat collisions and objects droppings from platform decks. The extent of damage caused by these loads ranges from total collapse of the structure to small damage which may not have serious consequence at the time of accident. To make optimal design decisions regarding structural safety and economical efficiency, it is very important to be able to assess the influence of damages on the performance of damaged structural members. In the End report, a series of calculations is performed to study the effects of different parameters on the load carrying capacity of such damaged members under pure bending. And the results of analysis are compared with experiment results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.04a
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• pp.59-76
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• 1996

Vessels in the world merchant fleet generally operate in either liner or bulk trade. The supply and the demand trend of general cargo ship are both on the ebb however those trend of tankers and containers are ins light ascension. Oil tankers are so far the largest single vessel type in the world fleet and the tanker market is often cited as a texbook example of perfect competition. Some shipping statistics in recent years show that there has been a radical fluctuation in spot charter rate under easy charter's market. This implies that the proper scheduling of tankers under spot market fluctuation has the great potential of improving the owner's profit and economic performance of shipping. This paper aims at developing the TS-DSS(Decision Support System for Tanker Scheduling) in the context of the importance of scheduling decisions. TS-DSS is defined as a DSS based on the optimization models for tanker scheduling. The system has been developed through the life cycle of systems analysis design and implementation to be user-friendly system. The performance of the system has been tested and examined by using the data edited under several tanker scheduling has been tested and examined by using the data edited under several tanker scheduling scenarios and thereby the effectiveness of TS-DSS is validated satisfactorily. The authors conclude the paper with the comments of the need of appropriate support environment such as data-based DSS and network system for successful implementatio of the TS-DSS.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.65-72
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• 2001

Since Pyoungtaek thermal power plant began using natural gas in 1986, the annual using volume has rapidly increased and reached 12.7 million tons in 1999. When the natural gas is cooled to a temperature of approximately -162$^{\circ}$C at atmospheric pressure, it condenses to a liquid called liquefied natural gas(LNG). LNG has a special characters such as odorless, colorless, non-corrosive, and non-toxic. So, LNG storage tank, tanker ship, transfer pipelines are required the special storage and transportation systems and technology. The presently operating LNG terminals are Pyongtaek and Inchon terminals. A total of 19 above-ground LNG storage tanks(100 thousand ㎘ grade) are currently in operation with a sendout capacity of 4,360tons/hour. To meet the growing domestic demand of LNG supply, the Inchon receiving terminal is expanding(six in-ground tank) and constructing a third LNG terminal at Tongyong. In this paper, case study on seepage analysis and countermeasure against increasing the seepage volume of in-ground LNG storage tank excavation work is reported. The results of an additional seepage analysis are presented to verify the design seepage volume of assumption section and seepage volume after curtain-grouting in the slurry wall.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1251-1256
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• 2014

The use of lubrication oil is of many purposes and one among them is to drive the engine mounted on a ship. Hence the supply of clean lubrication oil is important. And an oil purifier is one of key components in marine diesel engines. At present, the element type full-flow oil filter has been widely used for cleaning the engine oil. The self-driven centrifugal oil purifier is a device which is used to remove the impurities in lubrication oil using a jet flow. The flow characteristics and the physical behaviors of particles in this self-driven oil purifier were investigated numerically and the filtration efficiencies were evaluated. For calculations, a Computational Fluid Dynamics method is used and the Shear Stress Transport turbulence model has been adopted. The Multi Frames of Reference method is used to consider the rotating effect of the flows. The influence of centrifugal forcehas been numerically investigatedto improve filtration efficiency of tiny particles. As a result of this research, it was found that the particle filtration efficiency using the only center axis rotating and outer wall rotating system are higher than that of the fully rotating system in the self-driven oil purifier.

• Journal of the Korean Institute of Navigation
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• v.20 no.1
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• pp.27-46
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• 1996

Vessles in the world merchant fleet generally operate in either liner or bulk trade. The supply and the demand trend of general cargo ship are both on the ebb, however, those trend of tankers and containers are in slight ascension. Oil tankers are so far the largest single vessel type in the world fleet and the tanker market is often cited as a textbook example of perfect competition. Some shipping statistics in recent years show that there has been a radical fluctuation in spot charter rate under easy charterer's market. This implys that the proper scheduling of tankers under spot market fluctuation has the great potential of improving the owner's profit and economic performance of shipping. This paper aims at developing the TS-DSS(Decision Support System for Tanker Scheduling) in the context of the importance of scheduling decisions. The TS-DSS is defined as the DSS based on the optimization models for tanker scheduling. The system has been developed through the life cycle of systems analysis, design, and implementation to be user-friendly system. The performance of the system has been tested and examined by using the data edited under several tanker scheduling scenarios and thereby the effectiveness of TS-DSS is validated satifactorily. The authors conclude the paper with the comments on the need of appropriate support environment such as data-based DSS and network system for succesful implementation of the TS-DSS.