• Industry Promotion Research
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• v.1 no.2
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• pp.121-128
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• 2016

Cultural heritage means a great lot to a nation's social system and its people's behavior consciousness and plays an important role in its self-development and improvement. It is essential for a nation's self-education and renewal. Improper cultural heritage will be disastrous because it may fall a nation into a loss of terrible chaos. Only the proper cultural heritage can make it always self-awaking, self-correcting and remaining vital in life. This paper, from the perspective of Choi Bu's Pyohaerok, makes a thorough analysis of the unbalance heritage of Chinese ancient culture for thousands of years. For example, many fine traditions gradually vanished in our actual life or only take half their life in heritage nowadays, such as our ancient broad and profound Confucian etiquette, ancient exquisite brocade art and architecture, ancient advanced ship-building technology and many other advanced numerous technological inventions; however, too much unwanted cultural rubbish keeps constant prevailing and takes repeated successions in the life, such as the heavy-form-and-light-content management mode, borrowing power to do evil, neglecting technological inventions long time and generally believing in ghost theory,etc.. This paper mainly focuses on the partial successions of the bad cultural heritage and its bad influence on the country, and concludes that it is just that that makes the country more and more backward. Therefore, the paper makes some pondering over these issues and proposes some related ideas of country-building to attract others participation to deal with them.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.241-246
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• 2014

The purpose of this study is to investigate the flow characteristics around underwater triangular structure with various inclination and Reynolds number. A flow fields around the triangular structure model were measured by visualization method and PIV in the circulating water channel. The result of the experiment is where the triangular structure that has a inclination of $45^{\circ}$ and the reynolds number at $Re=2.9{\times}10^3$ showed rising velocity component to 2.7 times of the structure height. When the reynolds number is steady and when the inclination is greater the descending velocity component of the structure's rears current form is greatly shown and for the areas where it's more than y/hs=1.75 has a change in the angle of inclination but it doesn't give a great effect to it.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.107-113
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• 2010

The criteria of tugboat requirement in domestic trading ports have been determined by the administrator of regional maritime affairs and port office on the basis of the regulations for the tugboat operations and management. But, there is a little confusion that the criteria of tugboat requirement and method for calculation of them are different from port to port and total power calculated on the basis of power per tugboat requirements by the number of tugs is not in accordance with total required power for the use of tug in several ports. The comparison of tugboat requirements among domestic major ports showed that it should be necessary for the criteria to be made in unified form. Because the current criteria are only on the basis q the ordinary condition with wind velocity under 10m/s, the criteria on the condition of the wind velocity over 10m/s are suggested to be necessary for the precautions against a disaster such as unexpected strong winds or typhoon.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.465-472
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• 2016

Principal Component Analysis (PCA) is useful statistical technique for finding patterns in data, and expressing the data in such a way as to highlight their similarities and differences. In this paper, 1417 marine casualties occurred in Korean littoral sea in recent 5 years, were examined by the PCA. The main results obtained were as follows : 1. Most of marine casualties resulted from the human factors such as careless operation and insufficient engine maintenance. 2. Collision and standing mainly resulted from steering room-related human factors such as careless guard, inadequate ship-handling, however engine damage and fire explosion mainly resulted from engine room-related human factor such as bad handling of engine system. 3. No. 1 principal component represents accident frequency, No. 2 principal component represents the cause and No. 3 principal component represents the pattern of marine casualties, respectively.

• Journal of the Korea Society for Simulation
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• v.23 no.1
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• pp.33-42
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• 2014

In this paper we analyzed the search patterns for the anti-submarine warfare (ASW) surface ships cooperating with ASW helicopters. For this purpose, we modeled evasive motion of a submarine with a probabilistic method. And maneuvers and search actions of ships and helicopters participating in the anti-submarine search mission are designed. And for each simulation scenario, the case where a ship and a helicopter searches a submarine independently according to its optimized search pattern is compared with the case where the search platforms participate in the ASW mission cooperatively. Based on the simulation results, we proposed the reconfigured search patterns that help cooperative ASW surface ships increase the total cumulative detection probability (CDP).

• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.116-127
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• 1999

Line heating is a method widely used in forming ship hull surface. From the viewpoint of mechanics it is large deformation thermal elasto-plastic problem of arbitrary shaped plate. Many researches have been carried out to resolve this problem. Especially, Jang et al.[1] proposed a simplified thermal elasto-plastic analysis method to predict effectively the deformation of plate due to line heating. In this paper, we improved the method of Jang et al.[1] by considering tension yielding in temperature decreasing stage and verified with experimental results. FEA program using MITC4 degenerated shell element was made to deal with elastic large deformation problem. The newly proposed method can be used in the simulation and control of forming hull surface for higher productivity with simplicity and efficiency.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.104-109
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• 2015

The Korea Research Institute of Ships & Ocean Engineering (KRISO) has an ice tank to make a test environment similar to the real ice in the polar sea in order to carry out model tests. One of the most important task of the ice tank is to generate the model ice to have similar material properties as sea ice. The primary properties of sea ice which influence the ice performance of ice breakers and ice-strengthened vessels traveling in the polar sea are ice thickness, flexural strength, density, modulus of elasticity and crystal structure etc. Among them, since the density of model ice influences the buoyance resistance of ice for the ship model, the accurate measurement of ice density should be used to obtain the accurate analysis results from the model test. In this paper, some existing methods to measure the density of model ice are reviewed and a new one is proposed to measure it accurately and easily as possible. In this study, the measuring system including an UTM and several measuring devices was established to obtain the model ice density. Polyethylene and ice specimens are used for a series of repeatable measurement tests. From the results, it was recognized that both of the displacement method and the weight/weight methods gave the stable and favorable tendency.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.569-574
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• 2011

In research vessels or naval ships, airborne noise from machineries such as diesel engine is the major source of underwater noise at low speed. In this paper, effect of engine noise on underwater noise is studied by considering two paths; sound radiation from hull plate and direct airborne noise transmission through hull plate. SEA (Statistical energy analysis) is used to predict hull plate vibration induced by engine noise, where SEA model consists of only two subsystems; engine room air space and hull plate. The pressure level in water is calculated from sound radiation by plate. Engine noise transmission through hull plate is obtained by assuming plane wave propagation in air-limp plate-water system. Two effects are combined and compared to the measurement, where speaker is used as a source in engine room and sound pressure levels in engine room and water are measured. The hydrophone is located 1 m away from the hull plate. It is found below 1000 Hz, prediction overestimates underwater sound pressure level by 5 to 12 dB.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.341-345
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• 2008

The SiOC film of carbon centered system was prepared using bistrimethylsilylmethane and oxygen mixed precursor by the chemical vapor deposition. The chemical properties of the SiOC film were analyzed by the contact anlge and FTIR spectra. The dielectric constant of the deposited films decreased after annealing process, and the correlation between the increasing the BTMSM/$O_2$ flow rate ratio and the dielectric constant did not exist. However, the trend of increasing or decreasing of the dielectric constant repeated and there is the correlation ship between the dielectric constant and the Si-O-C bond in the range of $950{\sim}1200\;cm^{-1}$. The dielectric constant decreased between samples with the chemical shift. The lowest dielectric constant was 1.65 at the sample, which was observed the chemical shift.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.67-70
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• 2005

As the demand of sea leisure increases recently, interest is converged sea safety and offer of quick and systematic information according to weather environment that change rapidly. Use of Electronic Navigational Chart(ENC) in the sea in offer of geography information through Mobile terminal was gone to level that run in PDA environment in domestic by bulky good physician data information and complicated processing way of island in the sea expression in sea, and is loaded in obligatory sailing equipment of ship yet and is used. In this paper, we develop server system that take charge index for offer of quick information through Restrictive resource management and Caching Technique, image conversion and database construction and fast search to service various marine leisure informations of Weather Data and so on and image information of ENC in the sea to Mobile portable phone terminal efficiently.