• 융합신호처리학회논문지
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• 제16권3호
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• pp.108-114
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• 2015

선박의 평형과 균형을 위해 사용하고 있는 선박용 평형수는 선박의 이동과 함께 이동되며 선박의 화물 적재와 하역 시 선박용 평형수의 급수와 배수가 이루어지게 된다. 이를 통하여 유입된 외래 해양 미생물의 경우 새로운 환경에 적응하여 스스로 파괴되기도 하지만 적응을 하게 되는 미생물의 경우에는 강력한 번식력을 바탕으로 해양 생태계를 파괴하게 된다. 주로 사용되고 있는 자외선 살균 공법은 살균된 미생물의 기형변이 문제와 침전물 제거, 2차 평형수 저장 탱크의 살균 문제를 가지고 있다. 이에 본 논문에서는 퍼지 PID제어 기법을 이용한 램프 출력 조절 시스템을 구현하여 램프 파손 방지와 미생물 기형변이 문제를 억제할 수 있는 선박평형수 처리시스템을 개발 하였다. 실험 결과 초기 3분간은 해수의 급격한 온도 상승이 이루어졌으며 안정기 이후에서는 적정 온도를 유지하여 램프의 수명 연장과 해양 미생물의 기형변이 문제를 억제 할 수 있게 되었다.

• 동력기계공학회지
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• 제9권4호
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• pp.65-70
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• 2005

A liquid storage rectangular tank structures are used in many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. Many authors have studied vibration of cylindrical and rectangular tanks structures containing fluid. Few research on dynamic interaction among tank walls through fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass have to be considered. In the present paper, coupling effect between panels of tank structure on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region have investigated numerically and experimentally.

• Ocean and Polar Research
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• 제28권1호
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• pp.57-65
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• 2006

Various marine plankton were observed in the ballast water of vessels entering Incheon and Busan harbors. The ballast water of which age ranged from 2 to 54 days originated from the coastal waters of New Zealand, Taiwan, Singapore, Japan, Hong Kong and Pakistan, and from the Pacific Ocean. The total number of marine plankton taxa in 9 ballast tanks of different ships was 170: 90 phytoplankton, 24 protozoa and 56 zooplankton. The most diverse taxonomic groups were diatoms in phytoplankton, ciliates in protozoa and copepods in zooplankton. Classifying the specimens by size, above 50% of the number species of phytoplankton belonged to the size range between 50 and 150 Un. Protozoa and metazooplankton were found frequently in the size range between 50 and $120{\mu}m$ and 500 and $1,000{\mu}m$, respectively. The relationship between the species number and the age of ballast water was not significant. This is because of difference of filtration amounts derived from discordance of collecting samples. Among plankton observed in ballast water, some harmful algae and non-indigenous aquatic species were identified. Therefore, we need to investigate whether these species can inhabit in Korean coastal waters in further study.

• Journal of Advanced Marine Engineering and Technology
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• 제34권3호
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• pp.399-406
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• 2010

The aims of this study are to provide data on the ozone dosage control system and TRO sensor performance, to assess the performance of the degradation of total residual oxidant (TRO) neutralizer and to provide data on degradation rates of TRO in the ballast tanks, following treatment by the Ozone BWTS. This study includes the results of an evaluation of the TRO neutralizer, which was tested on the test barge. Accordingly, it has undertaken the evaluation of TRO degradation rates following treatment by the Ozone BWTS.

• 한국해양공학회지
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• 제27권3호
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• pp.8-14
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• 2013

Although there are various factors that threaten the security of ships, one of the most harmful is corrosion. It is not easy to find corroding areas and the status of corrosion, even though corrosion causes serious problems such as submergence and marine pollution as a result of leaking oil and polluted water. To monitor the corrosion of ships, non-destructive inspection, weight loss coupons, electrical resistance, linear polarization resistance, zero resistance ammeter, and electrochemical impedance spectroscopy have been developed. However, these methods require much time to detect corrosion, and most are not appropriate for real time monitoring. Coating, sacrificial anode, and impressed current cathodic protection (ICCP) methods have been developed to control corrosion. The ICCP and sacrificial anode methods are the most popular ways to prevent ship corrosion. However, ICCP is only appropriate for the outside of a ship and cannot be used for complex structures such as ballast tanks because these are composed of many separate chambers. Sacrificial anodes have to be replaced periodically. This paper proposes an integrated corrosion monitoring and control system (ICMCS) that can detect corrosion in real time and is appropriate for complex structures such as ballast tanks. Because the system uses titanium for an anode, exhausted anodes do not need to be replaced.

• 대한조선학회논문집
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• 제40권4호
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• pp.46-52
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• 2003

In ship structures, many parts are in contact with inner or outer fluid as stern, ballast and oil tanks. Fatigue damages can be sometimes observed in these tanks which seem to be caused by resonance. Tank structures in ships are in contact with water and the vibration characteristics are strongly affected by the added mass of containing water. Therefore it is important to predict vibration characteristics of tank structures. In order to estimate the vibration characteristics, the fluid-structure interaction problem has to be solved precisely. In the present paper, we have developed a numerical tool of vibration analysis of 3-dimensional tank structures using finite elements for plates and boundary elements for water region. To verify the present analysis, we have made an experiment for vibration characteristics of a tank with elastic opposite panels. And the added mass effect of containing water and the effect of structural constraint between panels are investigated numerically and discussed.

• 동력기계공학회지
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• 제14권6호
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• pp.67-74
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• 2010

Many tanks are installed in ship and marine structures. They are often in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine and propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tanks. Many authors have studied vibration of cylindrical and rectangular tanks containing fluid. Few research on dynamic interaction among tank walls through fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass have to be considered. In the previous report, A numerical tool of vibration analysis of a 3-dimensional tank is developed by using finite element method for plates and boundary element method for fluid region. In this paper, the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region and mode characteristics in accordance with changing breadth of the plates are investigated numerically and discussed.

• 제어로봇시스템학회논문지
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• 제19권8호
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• pp.688-693
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• 2013

This paper proposes a new method on attitude control of an underwater robot by using five ABTs (Attitude Ballast Tank). A pipe is connected to the bottom of the ABTs and transfers water by a pump, while another pipe is connected to the top of the ABT to transfer air. The buoyancy center of the underwater robot can be changed by means of the water transfer. This way, the attitude of the underwater robot can be maintained and/or controlled as desired. The changes of the center of gravity and the buoyancy central are estimated by a Lagrangian function which is similar to that for an inverted pendulum. The controller in this paper is designed by modeling of the underwater robot and selecting suitable gains of a PD controller which has fast response characteristics. This paper shows the possibility of the attitude control of an underwater robot by changing the center of gravity and the buoyancy center of the robot. Moreover, experimental results verify that the controller is effective in maintaining Roll/Pitch of the underwater robot with very low power consumption.

• 동력기계공학회지
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• 제9권4호
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• pp.71-76
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• 2005

Marine structures are often in contact with inner or outer fluid as stern, ballast and oil tanks. The effect of interaction between fluid and structure has to be taken into consideration when we estimate the dynamic response of the structure appropriately. Fatigue damages can also be sometimes observed in these tanks which seem to be caused by resonance. Thin walled tank structures in ships which are in contact with water and located near engine or propeller where vibration characteristics are strongly affected by the added mass of containing water. Therefore it is essentially important to estimate the added mass effect to predict vibration characteristics of tank structures. But it is difficult to estimate exactly the magnitude of the added mass because this is a fluid-structure interaction problem and is affected by the free surface, vibration modes of structural panels and the depth of water. I have developed a numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present study, the effect of added mass of containing water, the effect of structural constraint between panels on the vibration characteristics are investigated numerically and discussed. Especially a natural frequencies by the fluid interaction between 2 panels and a breath mode of the water tank are focused on.

• 동력기계공학회지
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• 제15권1호
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• pp.24-31
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• 2011

Rectangular box type structures are used in many fields of civil, mechanical and marine engineering. Especially, Most ship structures are often in contact with inner or outer fluid, like ballast, fuel and stem tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine and propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tanks. Many authors have studied vibration of rectangular tanks containing fluid. Few research on dynamic interaction among tank walls filled with fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass of water have to be considered. In the previous report, a numerical analysis is performed for the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing breadth of the plates by using finite element method for plates and boundary element method for fluid region. In this paper, the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing length, thickness, and boundary condition of the plates are investigated numerically and discussed.