• Bulletin of the Society of Naval Architects of Korea
• /
• v.20 no.2
• /
• pp.37-42
• /
• 1983

This paper presents a procedure within the framework of linear potential theory for predicting the lateral drifting forces on a cylinder floating on the free surface of a finite depth water. The disturbance of a regular incident wave caused by the presence of the floating body is represented by the sum of the diffracted and radiated wave potentials, which are determined by using Green's theorem. The lateral drifting forces are calculated by use of momentum theorem, and the scattered waves are expressed in their asymptotic forms. The computed lateral drifting forces on a Lewis form cylinder(b/T=1.25, $\sigma$=0.95) for water depth to draft ratio of 5.0 are compared with the Kyozuka's experimental results for a deep water, and found to be in good agreement. The water depth effects on drifting forces of the same model are also calculated.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.4
• /
• pp.1-8
• /
• 2000

The time simulation of motion responses of dolphin-moored BMP in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The hydrodynamic coefficient and first order wave exciting forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The second order wave drift forces and mooring for dolphin system are taken into account. As for numerical example, time domain analysis are carried out for a BMP in irregular wave condition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.11a
• /
• pp.77-79
• /
• 2023

국내 대표 해양도시인 부산시는 도시의 이미지를 향상시키고 경쟁력을 갖추기 위해 북항재개발지역과 원도심지역을 연계한 복합형 재생사업을 추진하고 있다. 부산남항은 북항과 원도심지역에 맞닿아있지만 고유의 특성이 고려되지 못하고 복합형 재생사업에 종속된 개발 압력을 받아왔다. 최근 해양관광벨트 형성에 있어 부산남항의 입지적 중요성과 북항·원도심지역과의 연계 필요성이 대두되며 부산남항을 대상으로 다양한 개발계획이 수립되고 있다. 항만재개발사업의 경우 대규모 SOC사업으로 추진과정에서 이해관계자 간의 갈등, 재정 문제 등의 여러 문제가 야기되는데 이러한 문제를 해결하지 못하면 사업이 표류 될 가능성이 크다. 따라서 본 연구는 부산남항 재창조를 위해 필수적인 항만재개발사업의 원활한 진행을 위한 추진전략과 민간참여방안을 제시하였다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.2
• /
• pp.150-155
• /
• 2012

One of the primary purposes of tugs is for the towing of other ships in salvage operations. In order to conduct such a task safely, the tug should be capable of generating the appropriate towing forces. Therefore the prediction of resistance against a towed ship during towing operation is a very important and essential procedure. This paper studies the ship resistance calculation program to predict towing force. The calculation program consists of the functions that calculate basic hull resistance in calm water, added resistance due to wind, drifting, hull roughness, waves, shallow water and currents. All predictions are calculated by statistical and empirical methods by graph or formula. The calculation results made by this program are compared with the results from the U.S. Navy's Towing Manual. These results confirm that this computer program is quite capable of appropriately predicting the resistance of damaged ships.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.17 no.2
• /
• pp.179-185
• /
• 2011

A marine collision accident occurred at the Jin-do water way. A barge loaded with heavy equipment of Power Generation Plant was being towed at its side by two tugs "A" and "B" from Byeg-pa harbour to the designated position to be used for power generation plant near Jin-do bridge. The Power Generation Plant was 40-meters high loaded atop the barge. When the "tugs and tow" were approaching the Jin-do the bridge, the two towing tugs lost maneuvering control of the barge and it went off-course, hit first the waterway embankment and finally struck the lower part of bridge's span and post musing the barge to capsize and sunk its cargo into the sea. The bridge also suffered damages where the top of the Plant struck At the time of the accident, there was a strong tidal current at the waterway. This paper calculates the safe towing force of barges with heavy loads when traversing in a strong tidal current situation in narrow waterway.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.9
• /
• pp.75-81
• /
• 2003

The longitude and latitude of a geosynchronous satellite are not defined as a point in space because of various external perturbations. To perform the missions of a satellite for a communication and broadcasting, the satellite must be positioned within a predefined station keeping box in given limited space longitude. In this study, we propose east-west station keeping box larger than that of north-south station. By using the derived error equation, we verified the Koreasat station keeping box allocation by assuming one week and two weeks of station keeping cycle.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.57 no.3
• /
• pp.236-245
• /
• 2021

In this study, a drifting test using a experimental vessel (2,966 tons) in the northern waters of Jeju was carried out for the first time in order to obtain the fundamental data for drift. During the test, it was shown that the average leeway speed and direction by GPS position were 0.362 m/s and 155.54° respectively and the leeway rate for wind speed was 8.80%. The analysis of linear regression modes about leeway speed and direction of the experimental vessel indicated that wind or current (i.e. explanatory variable) had a greater influence upon response variable (e.g. leeway speed or direction) with the speed of the wind and current rather than their directions. On the other hand, the result of multiple regression model analysis was able to predict that the direction was negative, and it was demonstrated that predicted values of leeway speed and direction using an experimental vessel is to be more influential by current than wind while the leeway speed through variance and covariance was positive. In terms of the leeway direction of the experimental vessel, the same result of the leeway speed appeared except for a possibility of the existence of multi-collinearity. Then, it can be interpreted that the explanatory variables were less descriptive in the predicted values of the leeway direction. As a result, the prediction of leeway speed and direction can be demonstrated as following equations. Ŷ₁= 0.4031-0.0032X₁+0.0631X₂-0.0010X₃+0.4110X₄ Ŷ₂= 0.4031-0.6662X₁+27.1955X₂-0.6787X₃-420.4833X₄ However, many drift tests using actual vessels and various drifting objects will provide reasonable estimations, so that they can help search and rescue fishing gears as well.

• Journal of Christian Education in Korea
• /
• v.67
• /
• pp.267-299
• /
• 2021

This study is purposed to discuss attributes and limitations of neo-liberalism and to offer some roles of Christian education corresponding neoliberalism. Neo-liberalism is an econosuperism that entrusts all things to market order, and it regards this market as utopia. It does not remain as just an economical principle, but influences all aspects in human life. Then it shows its religiosity connecting to capitalism. Every human in it is thought of as flexible workforces appropriate to neo-liberalism market. Such being the case neo-liberalsim strenghtens instrumentation in education. Then it distorts freedom and equality, and it weakens traditional values. Because of this, modern people's identity is getting to be lost and their human characters to be floated. This study discusses these things critically, and offers roles of Christian education such as founding a well balanced understanding on the Scripture against this neo-liberalsim market, restoring the essential purpose of education from instrumentation in education, and investigating and applicating a holistic human character on the basis of a Christian anthropology against this new human character of neo-liberalsim.

• Trans-
• /
• v.1
• /
• pp.117-139
• /
• 2016

Radio, the first broadcasting medium in history, is also the first mobile medium that meets the currently mobile ecology based on mobile communications network. As a result, it is easily approachable to consumers, can easily engage individual consumers, and its program contents have a huge appealing power to individual listeners, allowing it to form intimacy with audiences at the closest distance. However, the listening rating of radio has decreased greatly because it has experienced various changes by many other competitive media such as TV and internet and it has been influenced by relative constant hypothesis. Also, radio now faces a bigger competition due to the emergence of smartphone. In this circumstance, radio showed movements to evolve into a digital radio that presents improved sound, strengthened reception power, and increased number of channels, but it suddenly changed to DMB and portable multimedia DMB is having huge problems in its marketability due to smartphone. Yet, the listening rating of analogue radio broadcasting that remained unchanged was 13.99% in 2014, an increase by 47% from 2011, and the percentage of listeners under the age of 18 increased by 2.4 times from 2011 to 2014, which was a unique and interesting phenomenon. Accordingly, this paper compared the characteristics of internet and radio that have the traits of daily life, information, individuality, participatory, adventurousness, alternative media, expertise, and sound media. The paper then examined the listening method of radio, in which the direct groundwave antenna reception through a vehicular device is the most common form during the use of transportation means. Finally, it sought to investigate the future of radio based on the understanding of the increase in radio listening ratings, especially by comparing it to the characteristics of smart generation that focus on smartphone and the internet The study results demonstrated that entertainment and amusements are attempting at changes while they used to be obtained selectively by the smart generation from fragmentary information. In addition, radio is expected to become an influential medium in the future through its advantages of 'selected information' and reliability. However, considering such possibilities, radio needs to build the expertise and reliability of broadcasting contents much more at the same time as its digitalization, and it will be able to have its own competitiveness by focusing on various experiences and cultural exposures.