• Journal of the Korean Society of Marine Environment & Safety
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• v.7 no.2
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• pp.1-11
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• 2001

Many investments and works being continued to preserve green ocean in each countries of the world. Especial1y, the researches on the prevention of marine oil pollution being strengthened. It is not easy to disclose sludge oils that were produced necessarily in the ships operation, so that they are transferred to shore treating facility after collected inside the ship＇s sludge tank mostly. However, this shore transferring method is not only costly and time consuming but also entails risk of oil pollution. In this regard, it will be the best way to manage the sludge oils inside ship itself. The purpose of this study is to device an ultrasonic breaking systems which recycle the sludge oil from ships into usable oil to be burnt. In this paper, the first place, matrix structures of sludge fuel oil(SFO) and sludge lubricating oil(SLO) with the irradiation time for ultrasonic vibrator were interpreted. And, erosion damage for vibrator horn tip which is one of important part of ultrasonic breaking systems was examined under such an environment of the sludge oils. The material for horn tip is being made of SS41 steel and its erosion phase was investigated with variation of the vibration amplitude of 50${\mu}{\textrm}{m}$ and 24${\mu}{\textrm}{m}$ as well as the change of temperature in the oil environments. It is suggested that the experimental results can be helpful to the development of sludge oil disposing systems for the vessel.

• Ocean Systems Engineering
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• v.4 no.3
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• pp.215-241
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• 2014

Steel catenary riser (SCR) is a popular/economical solution for the oil/gas production in deep and ultra-deep water. The behavioral characteristics of SCR have a high correlation with the motion of floating production facility at its survival and operational environments. When large motions of surface floaters occur, such as FPSO in 100-yr storm case, they can cause unacceptable negative tension on SCR near TDZ (touch down zone) and the corresponding elastic deflection can be large due to local dynamic buckling. The generation, propagation, and decay of the elastic wave are also affected by SCR and seabed soil interaction effects. The temporary local dynamic buckling vanishes with the recovery of tension on SCR with the upheaval motion of surface floater. Unlike larger-scale, an-order-of-magnitude longer period global buckling driven by heat and pressure variations in subsea pipelines, the sub-critical local dynamic buckling of SCR is motion-driven and short cycled, which, however, can lead to permanent structural damage when the resulting stress is greatly amplified beyond the elastic limit. The phenomenon is extensively investigated in this paper by using the vessel-mooring-riser coupled dynamic analysis program. It is found that the moment of large downward heave motion at the farthest-horizontal-offset position is the most dangerous for the local dynamic buckling.

• Journal of environmental and Sanitary engineering
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• v.24 no.3
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• pp.28-36
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• 2009

We have closely examined the concentration change characteristics, emission amounts, and the material balance of hazardous air pollutants at both early and later stages of the prevention facilities. These results will be uses as the basic data when preparing for the regulatory and management plans for hazardous air pollutants. The results of the study on heavy metals illustrated that the content of heavy metals in sludge across five facilities were as follows: copper> zinc> chrome> nickel> cadmium> mercury. In terms of heavy metal content in swage sludge, the sludge in incinerating facilities other than the sludge in the D incinerating facility containing industrial water waste, was examined in order to satisfy the ocean contamination standard and fertilizer specifications. Most of the items were shown to have satisfied the emission tolerance standards in the latter part of the prevention facilities(The average elimination rate was over 90%). Therefore, it is concluded that swage sludge containing high-concentrate heavy metals needs to be incinerated rather than recycled as fertilizer.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.203-211
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• 2014

To raise the industrial competitiveness in the field of ship-building, it is crucially important that the yard should use production facilities and working space effectively. Among the related works, the management of tremendous blocks' number, the limited area of assembly shops and inefficient personnel and facility management still need to be improved in terms of being exposed to a lot of problems. To settle down these conundrums, the various strategies of block arrangement on the assembly floors have been recently presented and in the results, have increasingly began to be utilized in practice. However, it is a wonder that the sampled or approximated block shapes which usually are standardized projections or the geometrically convex contour only have been prevailed until now. In this study, all parts including the panel, stiffeners, outer shells, and all kinds of outfitting equipment are first extracted using the Volume Primitive plug-in module from the ship customized CAD system and then, the presented system constructs a simpler and more compact ship data structure and finally generates the novel projected contours for the block arrangement system using the adaptive concave hull algorithm.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.441-445
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• 2010

The ouput power of wave energy system in buoy is determined according to the inner diameter of oscillating water column and flow resistance. The increase of adhered shellfish inside the water column leads to decrease the inner diameter of wave energy converter. Influx loss of seawater reduces the efficiency of output power in the wave generation system. In this paper, the test result of AFS characteristic is described for preventing the deposition with shellfish and etc. The current of anode is controlled by buck converter, and the control algorithm developed for AFS in buoy. The experimental results is shown excellent preventing capapbility of AFS in buoy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.498-501
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• 2009

With increase of people's leisure time for marine facilities it is expected to increase the demand for marine tourism. It is necessary for lighthouse to meet the demand for marine tourism. Now, the lighthouse is not only functioning as a traditional aids to navigation for vessel, but also it becomes the new facility and space for all civilians who might visit and experience the marine culture. This research suggests how to use the facilities of the lighthouse as marine tourism resources by reviewing the cases of domestic lighthouses.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.235-243
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• 2020

Busan Port has a major function as the sixth largest port among the world container cargo standards and the second largest port among the world transshipment cargo standards. However, because of the lack of policy reflection on the port facility and carriers, overload control is a serious problem in freight transportation of transshipment cargo in Busan New Port and the port hinterland. In this regard, we reviewed the actual conditions of drivers, carriers, logistics managers, identified the problems, and suggest improvement plans.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.334-335
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• 2001

Common carp (Cyprinus carpio) and Israeli carp(C. carpio) samples were obtained from a aquaculture facility in the Kunsan National University, Korea. Genomic DNA was isolated from the common carp and Israeli carp representing genetic characteristics and genomic polymorphisms by polymerase chain reaction amplification of DNA as arbitrary primers. There were observed a total of 90 species-specific genetic markers within Israeli carp. On average, each random RAPD primer produced amplified 7.9 products from 1 to 17 bands. An average genetic similarity within Israeli carp showed -.60$\pm$0.05. The average level of bandsharing was some 0.57$\pm$0.03 between common carp and Israeli carp. Accordingly, two carp species were genetically a little distant. The electrophoretic analysis of PCR-RAPD proudcts showed high levels of variation between two fish species. The RAPD polymorphism generated by primer may be used as a genetic marker for species or lines identification in important aquacultural carp.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.491-494
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• 2019

The results from the analysis of recent security breach cases of industrial control systems revealed that most of them were caused by the employees of a partner company who had been managing the control system. For this reason, the majority of the current company security management systems have been developed focusing on their performances. Despite such effort, many hacking attempts against a major company, public institution or financial institution are still attempted by the partner company or outsourced employees. Thus, the institutions or organizations that manage Industrial Control Systems (ICSs) associated with major national infrastructures involving traffic, water resources, energy, etc. are putting emphasis on their security management as the role of those partners is increasingly becoming important as outsourcing security task has become a common practice. However, in reality, it is also a fact that this is the point where security is most vulnerable and various security management plans have been continuously studied and proposed. A system that enhances the security level of a partner company with a Virtual Desktop Infrastructure (VDI) has been developed in this study through research on the past performances of partner companies stationed at various types of industrial control infrastructures and its performance outcomes were statistically compiled to propose an appropriate model for the current ICSs by comparing vulnerabilities, measures taken and their results before and after adopting the VDI.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.3
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• pp.216-224
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• 2011

In This study develops a quasi-three dimensional numerical model of wave driven coastal currents with accounting the effects of the wave-current interaction and the surface rollers. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. The surface roller associated with wave breaking was modeled based on a modification of the equations by Dally and Brown (1995) and Larson and Kraus (2002). Furthermore, the quasi-three dimensional model, which based on Navier-Stokes equations, was modified in association with the surface roller effect, and solved using frictional step method. The model was validated by data sets obtained during experiments on the Large Scale Sediment Transport Facility (LSTF) basin and the Hazaki Oceanographical Research Station (HORS). Then, a model test against detached breakwater was carried out to investigate the performance of the model around coastal structures. Finally, the model was applied to Akasaki port to verify the hydrodynamics around coastal structures. Good agreements between computations and measurements were obtained with regard to the cross-shore variation in waves and currents in nearshore and surf zone.