• Journal of Navigation and Port Research
• /
• v.30 no.8 s.114
• /
• pp.617-622
• /
• 2006

Gamcheon Harbor was developed to cope with increased freight demand of Busan port and supplement function of the north port. Because container wharf is opened to 1997 as well as general wharf, present maximum 50,000DWT class containerships have been incoming and outgoing. However, In Gamcheon port, small size ships such as fishing boats, miscellaneous boats account for 50 percent of the traffic and a public marine products wholesale market that is building on the north wharf will open in 2008. Therefore, it needs to grasp future year traffic volume before establishing operation plan for port management. Also, analysis on crossing situation risk is required because the breakwater entrance in Gamcheon Harbor is narrow and the crossed passing of ship is ever-present at breakwater front. Thus the traffic volume in the future was presumed and quantitative analysis was achieved on crossing situation though simulations with the traffic volume.

• International Journal of Automotive Technology
• /
• v.2 no.1
• /
• pp.1-7
• /
• 2001

This paper presents further investigation into the effect of over-expansion cycle in a spark-ignition engine. On the basis of the results obtained in previous studies, several combinations of late-closing (LC) of intake valve and expansion ratio were tested using a single-cylinder production engine. A large volume of intake capacity was inserted into the intake manifold to simulate multi-cylinder engines. With the large capacity volume, LC can decrease the pumping loss and then increase the mechanical efficiency. Increasing the expansion ratio from 11 to 23.9 with LC application can produce about 13% improvement of thermal efficiency which was suggested to be caused by the increased cycle efficiency. The decrease of compression ratio from 11 to 5.5 gives little effect on the thermal efficiency if the expansion ratio could be kept constant. Thus, the expansion ratio is revealed to be a determining factor for cycle efficiency, while compression ratio is no more important, which suggests the usefulness of controlling the intake charge with intake valve closure timing. These were successfully explained by simple thermodynamic calculation and thus the mechanism could be verified by the estimation.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.1 s.28
• /
• pp.75-92
• /
• 2007

This article is to investigate the development of seamanship and the art of ship building, marine environment, Silk Road through the sea, and spice exchange at the trade growth of Song Dynasty. For better understanding marine environments, I exemplified what goes before such essential factors as experience and skills in maritime activities. I also demonstrated that South Song Dynasty's abundant economic strength and foreign opening strategy had been supervised systematically through the trade management organization and noted that the nation's overseas exchange had made great effects on its society. The import of the perfume provided the cause where the western influence occupies the orient in the same time when it is a keychains of the orient and the western interchange. For this reason, perfume, which once contributed 1/20 of the revenue, enlarged its portion to 1/10 of the revenue. This indicates the influence of perfume on the national finance in the Song period.

• Journal of Digital Convergence
• /
• v.11 no.3
• /
• pp.243-253
• /
• 2013

As global competition is more intensive, SCM is becoming more and more important in order to achieve competitiveness. It is necessary for firms to understand weak points among the integrated supply chain through supply chain assessment in order to implement SCM successfully and cost-effectively. In this paper, we review previous studies of SCM performance measurements and propose a supply chain assessment framework for shipbuilding industry, which is one of the major ETO industry. Based on 3 supply chain domains which are demand, supply, and product management, we decompose the whole supply chain process into 3 level lower processes and propose capability measurement matric for shipbuilding firms. A case study has been conducted to validate the proposed framework and results are presented at the end.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.2
• /
• pp.120-127
• /
• 2015

When a deep-seabed lifting pump is kept this device has bending and deformation in the axis due to its long length(8m). These influences can be caused a breakdown. Therefore, a mounting must be developed to keep the lifting pump safe. This paper discusses the hydraulic cylinder design of the lifting pump and structural safety estimation of the mounting using SBD(simulation-based design). The multi-body dynamic simulation method is used, which has been used in the automotive, structural, ship building, and robotics industries. In this study, the position and diameter of the hydraulic cylinder were determined based on the results of the strokes and buckling loads for the design positions of the hydraulic cylinder. A structural dynamic model of the mounting system was constructed using the determined design values, and the structural safety was evaluated using this dynamic model. According to these results, this system has a sufficient safety factor to manufacture.

• Plant Journal
• /
• v.13 no.2
• /
• pp.39-45
• /
• 2017

This paper is a study on FEED validation model that can be used in the bidding stage of small utility equipment in offshore plant industry using system engineering technique. Currently, domestic marine plant equipment industry companies are faced with the financial risk of project execution as they enter marine plant. The major cause was the insufficient ability to verify the FEED output from the contractor (Engineering or Procurement and Construction) of the equipment manufacturer (COMPANY or EPC). Therefore, we propose FEED design verification method that simplifies the system engineering method that sequentially applies requirements analysis, function, performance analysis and physical architecture building process. Also, we verified the suitability of the developed model by comparing the results of applying the developed FEED verification model and the verification method that depends on the existing experience for the small utility equipment (Air Compressor).

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.10 no.1
• /
• pp.95-102
• /
• 2018

This paper proposes a dual lifting and its cooperative control system with two different kinds of floating cranes. The Mega-erection and Giga-erection in the ship building are used to handle heavier and wider blocks and modules as ships and off-shore platforms are enlarged. However, there is no equipment to handle such Tera-blocks. In order to overcome the limit on performance of existing floating cranes, the dual lifting is proposed in this research. In the dual lifting, two floating cranes are well-coordinated to add up the lift capabilities of both cranes without any loss such that virtually a single crane is lifting, maneuvering and unloading. Two main constraints for the dual lifting are as follows: First, two barges of floating cranes should be constrained as a rigid body not to cause a relative motion between two barges and main hooks of the two cranes should be controlled as main hooks of a single crane. In order words, it is necessary to develop the cooperative control of two floating cranes in order to sustain a center of gravity of the module and minimize the tilting angle during the lifting and unloading by the two floating cranes. Two floating cranes are handled as a master-slave system. The master crane is able to gather information about all working conditions and make a decision to control the individual hook speed, which communicates the slave crane by TCP/IP. The developed control system has been embedded in the real floating crane systems and the dual lifting has been demonstrated five times at SHI shipyard in 2015. The moving angles of the lifting module are analyzed and verified to be suitable for hoisting control. It is verified that the dual lifting can be applied for many heavier and wider blocks and modules to shorten the construction time of ships and off-shore platforms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.159-163
• /
• 2005

Marine accidents of 70.9% have been caused by small ships less than 100 tons in the past 5 years(1998${\sim}$2002). This is ascribable to the graying and lack in expertise on shipping of small ship operators, and merchant ships are hindered from coastal navigation due to the increase of coastal fishing boats and liners. Currently, ECDIS and GPS Plotters are widely used as navigation equipment providing route information to operators, but it can not give any function of automatic route creation and route explanation, so they are available only experienced operators. Especially, the present situation is that no study is made of the automatic route creation and route explanation using ENC for ECDIS, substitution system of paper chart. In this paper, Navigation Guiding System(NGS) is proposed to generate an optimal route where ENC and GPS data is fusioned including the wind speed and direction of anemometer. The proposed system was testified by a simulation, and its effectiveness was verified.

• Journal of the Korean institute of surface engineering
• /
• v.49 no.3
• /
• pp.245-251
• /
• 2016

Galvanizing method has been extensively used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for ship building and various types of steels for the industrial fields etc.. However, the galvanized structures would be inevitably corroded rapidly with increasing exposed time because an acid rain due to environmental contamination has been much dropped more and more. Therefore, it has been made an effort to improve the corrosion resistance of the galvanizing film through various methods. In this study, comparison evaluation on the corrosion resistance of three types of the samples, that is, the hot dip galvanizing with pure zinc(GI), the hot dip galvanizing of alloy bath with zinc and aluminum(GL) and the pure zinc galvanizing steel immersed again to chromate treatment bath(Chro.)were investigated using electrochemical methods in 1% $H_2SO_4$ solution. The Chro. and GI samples exhibited the highest and lowest corrosion resistance respectively in 1% $H_2SO_4$ solution, however, the GI sample revealed the highest impedance at 0.01 Hz due to its high resistance polarization caused by corrosion products deposited on the surface, while Chro. sample exhibited the lowest impedance at 0.01 Hz because of little corrosion products on the surface. Consequently, it is suggested that the chromate treated steel has a better corrosion resistance in acid environment compared to pure galvanizing(GI) or galvalume(GL) steels.

• Journal of Navigation and Port Research
• /
• v.33 no.1
• /
• pp.35-41
• /
• 2009

A waypoint tracking algorithm(WTA) is designed for Unmanned Surface Vehicle(USV) in which water-jet system is installed for propulsion To control the heading of USV for waypoint tracking, the steering nozzle of water-jet need, to be controlled. Firstly, target heading is calculated by using the position information of waypoints input from the land control center. Secondly, the command for the steering nozzle of water-jet is calculated in real time by using the heading and the rate-of-turn( ROT) from magnetic compass, In this study, in order to consider the drift angle due to external disturbance such as wind and wave, the course of ground( COG) can be used instead of heading at higher speed than a certain value, To test the performance of newly-designed WTA, the tests were carried out in actual sea area near Gwang-an bridge of Busan. In this paper, the sea trial test results from WTA are analyzed and compared with those from manual control and those from commercial controller.