• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.1-6
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• 1989

This study was performed to reveal the heavy metal contents in apple leaves, and to estimate the correlation between contents of heavy metals of orchard lands and those of apple leaves. For this experiment, the apple leaves were collected from 58 apple orchards in Korea. The results were as follows ; 1. The average heavy metal contents in apple leaves were 26.44(6,23-182,85) ppm in Cu, 0.34 (0.07-0,61) ppm in Cd and 9.47 (0.00-225.50) ppm in Pb. 2. On the simple correlation coefficients between contents of heavy metals of orchard lands and those of apple leaves, all three copper cadmium and lead were positive but cadmium was insignificanfly, correlated. There was no difference among varieties (Ralls, Jonathan, etc) in these results. 3. The 0.1N HCl extraetion proved, was more suitable than the $IN-NH_4OAC$ extraction for describing the relation-Ship between heavy metal contents of apple leaves and those of orchard lands.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.3
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• pp.189-195
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• 2001

The characteristics of echolocation signals of the Common Dolphin, Delphinus Delphis was observed by the hydrophone in order to detect exactly distribution and migration on whales and dolphins in Korean Coastal waters. It's observation was carried out at the position of 13 mm off Gam-Po of Korean east-southern sea at 3rd-5th. April and 13th-15th. October, 1999. The results obtained are summarized as follows: (1) The frequency range of ship's noise and ambient noise in the observed station was 0.5-0.3 kHz, that ones could be influenced to the behavior of common dolphins which carry out echolocation using low-frequency. (2) The common dolphin was radiated single click of 8.6 ms and double click of 4.8 ms pulse width during these observation (3) The high click frequencies of common dolphin were 5.10 kHz, 7.22 kHz, 10.60 kHz with the click pulse width of 4.0 ms, 2.6 ms, 1.0 ms, respectively. In case of low-frequency 1-2 kHz, that is, 1.12 kHz, 1.38 kHz, 1.82 kHz, pulse width were 22.4 ms, 2.05 ms, 11.9 ms, respectively and they showed a tendency using triple click signal. (4) The pulse width, pulse recurrence interval and frequency range of the observed echolocation signals were 2.4-8.4 ms, 9.0-40.0 ms, 0.60-10.63 kHz respectively, and frequency spectrum level was 100-125 dB for single, double, triple click signals.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.79-83
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• 2006

Displayed result that handle particle contaminant and hydrospace organism included in number of ballast that is happened in ship using automatic bade washing filter. Reason that remove first contaminant that is included in number of ballast is that heighten processing effect of after processing process. of the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. The fact that it is easy to attach and detach a several type of screen for getting the expected water quality is another advantage. Filter rotation speed at 1.0rpm is filter resistance 3.0bar and 3.0rpm is filter resistance 2.8bar. Filter out impurities from ballast water over 6.0rpm is filter resistance 26bar and 10rpm is filter resistance 2.5bar. Filtration system removal aquatic organism over $80{\mu}m$ in ballast water. This study shows that the filtration treatment system has a potential for the treatment of ballast water.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.634-643
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• 2020

Because of the continuous increase in the demand for and importance of marine space, marine exploration and survey activities are being actively conducted in Korea actively. Because the marine survey vessels used for these activities have special operational patterns depending on the purpose and probe vessels, research on maritime traffic risk is required. In this study, an attempt was made to determine the correlation of each factor with the effect of marine exploration and survey vessel operation on maritime traffic. The status of ocean exploration and survey vessels in operation in Korea was identified, as well as the special operational conditions of some of the ocean physical probes. Generally, the number of exploration and survey vessels involved per hour, total vessel length(including exploration equipment), operation, interval distance of exploration as per plan, and marine traffic conditions(traffic volume and speed) can be classified as operating factors. To compare the results of the environmental stress, a maritime traffic flow simulation based on the "ES" Model was performed with each of the identified operating factors as independent variables. The results of the analysis confirmed that the environmental stress significantly changed in the order of traffic volume, ship length and speed. In addition, it was confirmed that the environmental stress is reduced when the operation course is set at an angle with the nearby maritime traffic flow. Accordingly, it can help reduce the operator's burden if the survey vessel operator understands nearby maritime traffic conditions and reflects them in the operation method when setting the operation plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.78-87
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• 2017

Recently, the quality of a product or system has becoming increasingly important as it means customer satisfaction. The function, which is recognized as a nature of this quality, means how it functions well so it is the closest to the customer satisfaction. On the other hand, it is becoming more important as safety is closely related to destruction or human injury from accidents for engineers who handle large-scaled structures, such as ships. This study analyzed the function using quality function development (QFD) and considering the function and safety, which are being recognized as important in the structure. In addition, the safety and the quality analysis method based on the customers' needs was analyzed using failure mode and influence analysis (FMEA). In addition, the supplementary materials that are important in terms of the aspect of safety and function for the quality enhancement of a hatchway system were determined by applying a bulk carrier and hatchway. As a result, there are commonly understood items in important supplementary materials and parts, which are determined individually in terms of function and safety, because they can enhance both the function and safety simultaneously. This study shows that designers can improve the quality of products and systems by enhancing these supplementary materials and parts with greater interest.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.674-680
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• 2013

As the range of marine leisure activity gradually expands to ocean-going, a habitable cruise boat has been getting the limelight. Advanced countries in the marine leisure industry in Europe and North America have already secured their competitiveness in designing and building cruise boats by elegant design, ergonomic structure and fuel efficiency through the adoption of light-weight hull materials. In contrast, mostly small power boats are developed and built in Korea, and GFRP take up the most of hull materials. This study inquired into the design and characteristics of a 50ft-class CFRP that ocean-going is possible. The hull-form of the CFRP cruise boast were analyzed to propose a hull form for the designed ship (MMU-C.B), and based on that, the design model of the MMU-C.B was built. Finally, the MMU-C.B's characteristics of the resistance performance and hull-planing were found by comparative reviews with the results of model tests of GFRP pleasure yachts.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.206-218
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• 2020

Located mostly inside the megacity of Busan, the Busan Southern Port is a multifunctional port with various nearby industry activities, including a joint fish market, ship repair facilities, and fishing boat facilities. If toxic chemicals generated by the industrial activities continue to flow into and accumulate in the sediment of the port, they can affect aquatic ecosystems and humans. Therefore, in this study, distribution levels and potential influent sources of organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and butyltin compounds (BTs), in the sediment were investigated. The sediment samples were collected from eight sampling sites in November 2013 (first phase) and November 2014 (second phase). The mean concentrations of PAHs, PCBs, and BTs in the first and second sampling phages were 4174.0 ng/g-dry wt. and 1919.0 ng/g-dry wt., 166.3 ng/g-dry wt. and 21 ng/g-dry wt., and 50.9 ng/g-dry wt. and 30.8 ng/g-dry wt., respectively. The concentrations of the organic pollutants detected in the seabed sediments were lower in the second phase than in the first phase. In this study, the inflow sources of PAHs, PCBs, and BTs were found to be combustion, land, and municipal sewage or industrial wastewater, respectively.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.173-179
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• 2006

A number of perforated plates are utilized for the passage of the crew and the equipment, reducing weight and the arrangement of piping. Hull girders in double bottom and floor plates are the typical parts which have those plates in a ship structure, and the perforated plate is usually positioned at the place which has less loading without local strength problems. In the case of utilizing the plate inevitably at the place which has large strength, an opening of the plate has large effect on the buckling strength due to in-plane rigidity and ultimate strength. Therefore the assessments of the elastic buckling strength and the ultimate strength for the perforated plate are the essential requirements for determining the dimensions of the parts at the initial design stage. With above reason, a need of the reasonable assessments for the elastic buckling strength and the ultimate strength has evolved. The numerical series analysis with the consideration of the effect due to various aspect ratios and slenderness ratios were performed using finite element method in this research. Simple formulas for the design are also proposed from the above analysis.

• Journal of Navigation and Port Research
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• v.36 no.1
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• pp.21-26
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• 2012

Recently, vessel hijacking by pirates has been a big issue around the world. For example, the hostages of VLCC "SAMHO Dream" were released for a large sum of ransom. On January 20, 2011 "SAMHO Jewelry" succeeded releasing all of the 21 crews on the vessel by attacking the pirates in international waters for the first time since the founding of the Naval Force. Furthermore, the "HANJIN Tianjin" crews evacuated to the Citadel promptly and were rescued by the navy. As hijacking of Korean vessels by pirates is increasing, various safety measures must be implemented. As a matter of fact, the standard for ship's facilities has been partially revised and setting up an evacuation shelter on all vessels sailing dangerous zone has been reinforced. This research aims to discuss crew Citadel installation on vessels intended for long haul. In addition, it will look at measures against potential gas flow in the event of pirate armed attacks and fire outbreak onboard a vessel. It will also assess the optimal number of crew Citadels theoretically. Lastly, the optimal number of shelters in the event of fire outbreak will be discussed based on an FDS simulation.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.127-138
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• 1996

The strip method, unified theory and 3-D panel method are commonly used methods for the seakeeping analysis of high-speed vessels. The strip method which is basically 2-dimensional method is known to give incorrect hydrodynamic coefficients and motion responses for the cases of high speed and low frequency region. And the unified theory which uses two dimensional approach in inner domain and slender body theory in outer domain is very complicate in computational modelling. Though the 3-D panel method requires comparatively long computation time, it is believed that the method gives good results without any limitation in ship speed and range of frequency for computation. In the 3-D panel method the source singularity representing translating and pulsating Green function is used and Hoff's method is adopted for the numerical calculation of the Green function. The computation time can be reduced by using the symmetry relationship with respect to longitudinal axis. In this paper the strip method and the 3-D panel method are compared for the seakeeping analysis of a high-speed catamaran. The Compared items are the hydrodynamic coefficients, wave exciting forces, frequency response functions and short-term responses in irregular waves.