• Journal of Navigation and Port Research
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• v.41 no.4
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• pp.235-242
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• 2017

Earnings management is defined as an intentional act during the financial reporting process or a manager's choice of accounting policies to avoid earnings decreases or obtain some private gains. Shipping firms have a highly debt-intensive capital structure and a significant motivation in earnings management to avoid failure of a Debt Covenant. From this point of views, this paper tries to determine the relationship between the capital structure and discretionary accruals estimated using the re-modified Jones model (1995). The sample used to test the research models is made up of 87 Korean shipping firms during the period from 2007 to 2015. A histogram analysis, t-test and FGLS confirm the possibility of using earnings management, and it proved that Korean shipping firms manage their earnings to avoid financial loss. An analysis of the relationship between the capital structure and earning managements, shows it is difficult to support the Debt Covenant, shown as a negative relationship between the debt ratio and debt maturity as shipping firms' capital structure and discretionary accruals as earning management variable. An additional analysis presents a negative relationship between previous debt maturity and discretionary accruals, and the possibility of earning management in a highly increased debt ration group.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.203-210
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• 2007

This paper treats optimal route safety assessment system at seaway based on weather forecasting data through INMARSAT. Since early times, captain have been sailing to select the optimum route considering the weather, ship loading status condition and operational scheduling empirically. However, it is rare to find digitalized onboard route support system whereas weather facsimile or wave and swell chart are utilized for the officer, based on captain's experience. In this paper, optimal route safety assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA(estimated time of arrival) and fuel consumption that shipping company. and captain are requiring to evaluate for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method Basically, the weather forecast is assumed to be prepared previously in order to operate this system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.476-482
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• 2013

This study aims to enhance the effectivity of VTS(Vessel Traffic Service) control by investigating the minimum safe distance between vessel and vessel, vessel and land(obstacle) for the vessel's safe navigation within the VTS control area. In addition, to suggest basic data for the safe navigation, this study has done survey and analysis to each VTS center, and individual on the minimum safe distance to VTS operators of each ports of korea. Through ocean voyage by training ship, Singapore and Malacca strait's congested vessel traffic zone's control distance was compared and investigated the difference on safe distance by the different VTS operators. As a result, there was huge difference of minimum safe distance between the VTS operators belong to the same center. Over all, the port with gentle coastline, like donghae, the safe distance was wider than the other port. On the other hand, port with complex coastline and frequent entry and departure of the vessel, like mokpo, the safe distance was the shortest of all. Therefore, development of module suitable to port's natural conditions and traffic volume's necessity is required, for the operators affiliated to the same VTS center control according to formal method. Lastly, the full discussion by the expert group about establishment of standard control procedure in the future should be considered as well.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.389-394
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• 2005

The additional moment occurs because the superstructures of VLFS are influenced by wave loads instead of earthquake loads. In order to reduce the additional moment, this study used the semi-rigid connections which lie between fully rigid and pinned. If the semi-rigid connections are used for superstructures of VLFS, the moment of beams can be reduced and more economical construction will be possible. This study aims to show the effect of wave loads on structure and the efficiency of the semi-rigid connections due to wave loads by analyzing the time history responses. The dynamic behaviors of the rigid frame are compared with those of the semi-rigid frame considering of static loads, wave loads and combination loads for a four-bay, three-story frames. The semi-rigid connection type is a steel tubular column with square external-diaphragm connections and the time history analysis is used for the dynamic responses. The additional moment responses due to wave loads increase $33\%$ in the rigid frame, $26\%$ in the semi-rigid frame with the spring model.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.343-349
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• 2006

In order to enhance the robustness against noisy environment, the previous GPS initial synchronization method of DGPS reference stations adopts not only the coherent integration method but also the non-coherent integration method. However the previous GPS initial synchronization method muses the non-coherent integration loss, which is a dominant factor among the signal acquisition losses in noisy environment. And the non-coherent integration loss increases with the strength of noise signal. In this paper, a novel GPS initial synchronization method is proposed for robust DGPS reference stations in noisy environment. This paper presents that the proposed GPS initial synchronization method suppresses the non-coherent acquisition loss. Furthermore, with regard to the mean acquisition time, it is shown that the number of the search cells of the proposed GPS initial synchronization method is much smaller than that of the previous GPS initial synchronization method Finally, through the simulation by the GPS simulator, it is seen that the GPS signal of nigh signal-to-noise ratio can be acquired under increased noise floor using the proposed GPS initial synchronization method.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.313-318
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• 2015

A question has recently been raised as to whether a foreign officer needs to obtain a Korean endorsement in order to be able to serve on board a Korean flag ship. This is attributable to the fact that differences of viewpoint may arise as to the interpretation on the relation between the mutatis mutandis article 24(1) and the endorsement issuance article 10 bis. This study intends to propose an interpretative solution through conducting in-depth analysis on the article 25(1). The conclusions of this study can be given as follows. First, the jurisdiction over the bareboat charter ships with hire purchase shall be rested with the third country of which the flag the ship is flying, the endorsement to be issued to foreign officers have to be issued by the flag State under the STCW Convention as ameded. Second, the provisons of the ship officers' act shall not be made applicable, commensurate with the intention of legislating the mutatis mutandis article 25, to the BHC/HP in such a way that is in infringement with the jurisdiction of flag State of those foreign ships. Third, the mutatis mutandis article shall be made applicable to only such areas of manning standards not covered under the STCW Convention as amended and shall exclude those provisions pertaining to the issuance of various certificates of which the jurisdiction is rested with flag State under the international instrument. Fourth, the article 10 bis(1) is not a provision requiring foreign officers wishing to serve on a BBC/HP to obtain a Korean endorsement. In summation, the article 10 bis shall be used only in the cases where foreign officers wishing to serve on a Korean flag ship are required to obtain korean endorsement.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.277-283
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• 2015

MS(Mild Steel), HTS(High Tensile Steel), HYS(High Yield Steel), AL(Aluminum Alloy) and Composite Materials are used for vessels. Steel Materials are mostly used for vessels because body of a ship have to perform the basic functions such as watertight, preserving the strength and supporting the equipments. The vessels primarily carry out a mission at ocean, so that body of a ship is necessarily rusted. There are several methods to protect the corrosion of vessels such as painting, SACP(sacrificial anode cathodic protection) and ICCP(impressed current cathodic protection). For the sacrificial anode cathodic protection, Al and Zn alloys are normally used. Heavy metals are added to the Al and Zn Alloys for improving the corrosion properties but they are so harmful to the human and environment. Therefore, the use of these heavy metals is strictly regulated in the world. In this paper, Al and Zn Alloys are made by adding the trace elements(Ma, Ca, Ce and Sn) which is not harmful to the human and environment. SEM, XRD, Potentiodynamic Polarization test and Current Efficiency test are conducted for evaluation of Al and Zn Alloys. As a result of the experiment, Al-3Zn-0.6Sn and Zn-3Sn Alloys are more efficient than other Alloys.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.167-174
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• 2009

Recently, design technology of has been required such as catamaran yacht with high-speed according to expand a marine leisure industry. The domestic technical development for design and production of yacht is not actively than Canada, USA, Japan etc. However, with further development of yacht design & technology, it is need to develop a key technology related to increase the value of catamaran yacht. In the present paper, new guideline is suggest for catamaran yacht as like kinds of marine leisure ship in order for fundamental structure design and structural analysis for twin-hulled ship yacht and techniques for structural analysis as sea leisure ship in this research. The class of society has not been proposed formally about regulation and methodology for estimation of strength of small hight-speed craft with satisfying two conditions as noted; length less than 50meters, ratio of length to breadth less than 12. In the present study, we were adopted DNV (Yachts, Design Principles, Design Loads, Hull Structural Design) Rule and KR (FRP rule application guide) for scantling of structural members. Furthermore, ABS rule is used for structural calculation about application of loading conditions for catamaran yacht. This study can be available feedback role to manufacture of 38ft diffusion style for catamaran yacht. It is expected that this study will be a good reference in order to design of catamaran yacht with high-speed.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.367-373
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• 2010

When the numerical analysis is carried out, it is necessary to set proper elements as a feature of analysis domains for more accurate simulations. In this study, Distinct Element Method(DEM) is applied, only considering repulsive force and tensile force except for frictional force and resisting force of particle. When the filled particles with initial Quad-tree type is relocated by DEM, a blank space existing among the particles can be minimized because the shape of particle is circular. Finally, it is the effective feature that the centroidal disposion of the particles is similar to an equilateral triangle. Triangular mesh are formed by using the Delaunay triangular technique on these relocated particles, the quality of triangular mesh is more improved by carrying out Laplace interpolations. The compared result of Aspect Ratio before and after the Laplace interpolation is shown that although the quality of triangular mesh made by DEM is good, the later triangular mesh are higher quality than the formers. In this study, although the developed technique takes a longer calculational time than the previous technique to generate triangular mesh, it is considered that the applicable possibility is very high in the generation of finite element mesh about wave analysis and various numerical simulation to need a complex or reappearance of exact topography.

• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.419-427
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• 2013

The purpose of this study was to analyze the perceptions to improvement directions of related regulations for water leisure activation. In order to accomplish such study purpose, the study utilized a survey methodology with 205 water leisure participants and 117 water leisure business employees. In addition, this study attempted to review the license and education system, registration and inspection system and business organizations from the advanced countries such as US, British, Australia and Japan. Accordingly, following findings were derived from current study. First, the problems of current license system included difficulty of operating the system and deficiency of operating organizations, and the improvement directions included expansion of education organizations and differentiation of education based on levels. Second, the improvement directions of registration and inspection included simplification of registration procedures and expansion of registration and inspection organizations. Third, difficulties perceived by business employees included complexity of entry and departure, complexity of registrating water leisure business and insufficiency of supporting business policies. In conclusion, water leisure related regulations including Water Leisure Safety Act need to be reformed continuously to reflect changing demands and needs from participants and business sectors.