• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.617-629
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• 2022

This study empirically analyzed the mediating effect of technology absorption capacity in the relationship between technological innovation of ship parts manufacturing companies on business performance. Through this, it will be possible to provide implications for improvement plans for management strategy establishment related to technology development in the future. In order to achieve the purpose of this study, R&D, marketing, production·A total of 362 people working in manufacturing and finance/accounting departments were selected as subjects for this study. As a result of this study, it was found that technological innovation and technology absorption capacity of ship parts manufacturing companies have a positive (+) effect on business performance. The conclusion based on these research results is that the potential absorption capacity and realized absorption capacity constituting technology absorption capacity are judged to be the main key factors between technological innovation and management performance, such as continuous technological capacity accumulation. From a practical point of view, the ship parts manufacturing industry needs to focus on its ability to absorb smart parts process technology.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.418-426
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• 2015

Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.760-768
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• 2009

In this paper, we propose the energy efficient transmission parameter selection method for Wireless Personal Area Network (WPAN) system which is applied to e-Navigation system considering various ship models environment. An appropriate selection of transmission parameters of HR-WPAN system is very essential to be considered for saving WPAN devices' energy consumption, when HR-WPAN system is applied to ship area network (SAN). Therefore, we propose an energy consumption model for a ship area network employing IEEE 802.15.3 based CSMA/CA HR-WPAN model and analyze the effect of transmission parameter selection on the performance of energy consumption. In particular, the path loss is the major performance decision parameter for the SAN employing HR-WPAN system, since it varies according to the material of shipbuilding such as steel(for large ship), FRP(for medium size ship) and compound wood(for small ship). Thus, we analyze and demonstrate that the proper transmission parameter selection of transmit power, PHY data rate and fragment size for each ship model could guarantee energy efficiency.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.33-41
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• 2002

This paper deals with the development of simulation model for the container terminal consisting of 3 berths, 8 container cranes, 16 yard blocks with each yard cranes and 90 yard trucks in order to evaluate the various operational rules. The proposed operational rules are 3 ship dispatching rules, 3 berth allocation rules, 2 crane allocation rules, 2 yard allocation rules and 2 yard truck allocation rules and 4 performance measures like ship time in the terminal, ship time in the port, the number of ships processed and the number of containers handled are considered. The simulation result are as follows. 1) no difference among 3 ship dispatching rules, 2) berth allocation rules depends on performance measures 3) dynamic crane allocation is better than fixed policy 4) pooling yard allocation is better than short distance yard allocation rules and 5) fixed yard truck allocation by berth is a little better than pooling policy.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.619-621
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• 2005

This paper proposes apractical design method for ship-to-ship missiles' autopilot. When the pre-designed analogue autopilot is implemented in digital way, theygenerally suffer from severe performance degradation and instability problem even for a sufficiently small sampling time. Also, aerodynamic uncertainties can affect the overall stability and this happens more severely when the nonlinear autopilot is digitally implemented. In order to realize a practical autopilot, two main issues, digital implementation problem and compensation for the aerodynamic uncertainties, are considered in this paper. MIMO (multi-input multi-output) nonlinear autopilot is presented first and the input and output of the missile are discretized for implementation. In this step, the discretization effect is compensated by designing an additional control input. Finally, we design a parameter adaptation law to compensate the control performance. Stability analysis and 6-DOF (degree-of-freedom) simulations are presented to verify the proposed adaptive autopilot.

• Journal of the Korean Institute of Navigation
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• v.13 no.2
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• pp.57-73
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• 1989

This paper presents a practical method to predict the characteristics of ship manoeuvring motions. A attempt is made to calculate the manoeuvring motions utilizing principal particulars of ship hull, properller and rudder as basic input data. The mathematical models, which describe the ship manoeuvring motions, are developed on the basis of MMG(5), Inoue(17), Hooft(18) and so on. Calcuations of manoeuvring motions for three kinds of typical characteristics, namely turning motion, zig-zag manoeuvre response and steady turning performance, are carried out. In order to examine the validity of the calculation method of this paper, simulations are run for seven merchant ships employed by Inoue(4). The computed results by present method are compared with full scale trials and Inoue's calculations(4). It can be concluded that the calculation method proposed in this paper is useful and pwoerful for prediction of characteristics of ship manoeuvring motions at the initial design phase or the application study on manoeuvring motions.

• Journal of Korea Port Economic Association
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• v.18 no.1
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• pp.27-41
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• 2002

This paper deals with the development of a simulation model for the container terminal, which consists of 3 berths, 8 container cranes, and 16 yard blocks with each yard crane and 90 yard trucks in order to evaluate the various operational rules. The proposed operational rules are 3 ship-dispatching rules, 3 berth allocation rules, 2 crane allocation rules, 2 yard allocation rules, and 2 yard truck allocation rules. These rules are simulated using 4 performance measures, such as ship time in the terminal, ship time in the port, the number of ships processed, and the number of containers handled. The simulation result is as follows: 1) there is no difference among 3 ship-dispatching rules, 2) berth allocation rules depend on performance measures, 3) dynamic crane allocation is better than fixed policy, 4) pooling yard allocation is better than short distance yard allocation rules, and 5) fixed yard truck allocation by berth is a little better than pooling policy.

• Selected Papers of The Society of Naval Architects of Korea
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• v.1 no.1
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• pp.37-44
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• 1993

Deck wetness phenomenon has long been considered as one of the factors that degrade the performance of a ship In waves. In rough weather, the frequent skipping of water may give rise to the capsizing of the ship. Therefore an appropriate above water bow shape design is an important asset to a ship of which successful performance in rough weather is a prerequisite such as a warship. In this paper an experimental technique for estimation of deck-wetness frequency is presented. The results of the model tests are compared with those of computations using Ochi's formula. Finally the applicability of Ochi's formula is discussed.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.16-25
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• 2024

By deriving the limitations of the test evaluation, it was intended to suggest a plan to improve the test evaluation system for the appropriateness of the number of ship crews according to the design and construction of troops-saving ships. Currently, the number of crew members by ship type is confirmed and specified in the ROC(Operation Requirement Performance) in the early stages of design, such as conceptual design, but there is a limit to testing and evaluating the appropriateness of ensuring reliability of combat performance.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.347-360
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• 2014

The auto-berthing of a ship requires excellent control for safe accomplishment. Crabbing, which is the pure sway motion of a ship without surge velocity, can be used for this purpose. Crabbing is induced by a peculiar operation procedure known as the push-pull mode. When a ship is in the push-pull mode, an interacting force is induced by complex turbulent flow around the ship generated by the propellers and side thrusters. In this paper, three degrees of freedom equations of the motions of crabbing are derived. The equations are used to apply the adaptive backstepping control method to the auto-berthing controller of a cruise ship. The controller is capable of handling the system non-linearity and uncertainty of the berthing process. A control allocation algorithm for a ship equipped with two propellers and two side thrusters is also developed, the performance of which is validated by simulation of auto-berthing.