• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.23-28
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• 2007

This study estimated the behavior(movement) characteristics of floating marine debris flowing in the Nakdong River Estuary using a simple numerical particle-tracking model. This numerical experiment considered the maximum water discharge outflow from the Nakdong River barrage during the passage of typhoon Maemi in 2003. The simulation showed that the particle distribution and movement of floating marine debris in the Nakdong River Estuary reached a stable state at 72 hours after the typhoon had passed, during the flαxl period of river discharge. The quantity of floating particles distributed on the east coast of Gadeok and Jinu Islands increased by 40% at 33 hours after starting the model, while the change in other sea areas was $20{\sim}40%$.

• Journal of Ocean Engineering and Technology
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• v.29 no.5
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• pp.373-379
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• 2015

Side Scan Sonar (SSS) is capable of acquiring real-time data for seabed scouring, bathymetry, mine countermeasurement, etc. In a shipyard, an SSS package is utilized to measure the water depth and find debris in the sea because a sufficient water depth and non-interruption have to be ensured before implementing an underwater installation such as a large thruster. This paper presents the application and operation method of an SSS for the construction of an offshore project.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.2
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• pp.152-163
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• 2000

Floating resin pellets including plastics were surveyed from 7 coastal beaches near Young-il Bay during summer and winter season on 1998 ~ 2000 year. Plastic fabrication materials in the survey were founded with 6 items using the following; resin pellets, plastic debris, styrofoams, cigar filters, wood pieces and charcoals. The results deduced in the areas are as follows: 1. The seasonal variability of the all debris is revealed that summer season were remarkably larger than those of winter. This is deduced it is attributed to meteorological effects, e.g, the seasonal wind strength, current vectors and resorts of crowded people for beach enjoy. And the distribution of plastic debris is Pohang Songdo $12.9ea/m^2$, Pohang Bookbu $8.8ea/m^2$, Togoo $4.9ea/m^2$, Chilpo $3.2ea/m^2$, Hwajin $1.4ea/m^2$, Wolpo and Guryongpo $0.8ea/m^2$ respectively. 2. Compared with each beaches, Songdo beach, northern part beach of Pohang city and Togoo beach have higher densities than those of the others. Especially, the highest densities of all debris were discovered in the Songdo beach of Pohang city. 3. The change of density over the whole year was similarly distributed in quantities and fabrication materials. 4. These surveys were founded that the most parts of plastic debris materials were made up with PE and PP.

• Ocean and Polar Research
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• v.24 no.3
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• pp.289-300
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• 2002

The Lago Sofia conglomerates encased in the Cretaceous Cerro Toro Formation, southern Chile, represent a gigantic submarine channel system developed along a foredeep trough. The channel system consists of several tributaries along the trough margin and a trunk channel along the trough axis. Voluminous debris flows were generated ubiquitously along the tract of the submarine channel mainly by the failure of nearby channel banks or slopes. The flows transformed immediately into multiphase flows and resulted in very thick-bedded mass-flow deposits with a peculiar structure sequence. The mass-flow deposits commonly overlie fluted or grooved surfaces and consist of a lower division of clast-supported and imbricated pebble-cobble conglomerate with common basal inverse grading, and an upper division of clast- to matrix-supported and disorganized pebble conglomerate or pebbly mudstone with abundant intraformational clasts. The structure sequence suggests a temporal succession of a turbidity current, a bipartite hyperconcentrapted flow with active clast collisions near the flow base, and a cohesive debris flow probably with a rigid plug. The multiphase flow is interpreted to have resulted from transformation of clast-rich but cohesive debris flows. Cohesive debris flows appear to transform more easily into dilute flow types in subaqueous environments because they are apt to hydroplane. This is in contrast to the flow transitions in subaerial environments where noncohesive debris flows are dominant and difficult to hydroplane.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1583-1600
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• 2015

When natural disasters occur, including earthquakes, tsunamis, and debris flows, they are often accompanied by various types of damages such as the collapse of buildings, broken bridges and roads, and the destruction of natural scenery. Natural disaster detection and warning is an important issue which could help to reduce the incidence of serious damage to life and property as well as provide information for search and rescue afterwards. In this study, we propose a novel computer vision technique for debris flow detection which is feature-based that can be used to construct a debris flow event warning system. The landscape is composed of various elements, including trees, rocks, and buildings which are characterized by their features, shapes, positions, and colors. Unlike the traditional methods, our analysis relies on changes in the natural scenery which influence changes to the features. The "background module" and "monitoring module" procedures are designed and used to detect debris flows and construct an event warning system. The multi-criteria decision-making method used to construct an event warring system includes gradient information and the percentage of variation of the features. To prove the feasibility of the proposed method for detecting debris flows, some real cases of debris flows are analyzed. The natural environment is simulated and an event warning system is constructed to warn of debris flows. Debris flows are successfully detected using these two procedures, by analyzing the variation in the detected features and the matched feature. The feasibility of the event warning system is proven using the simulation method. Therefore, the feature based method is found to be useful for detecting debris flows and the event warning system is triggered when debris flows occur.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.289-294
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• 2023

We discovered a halacarid mite species, Isobactrus tuberculatus Abé, 1996, inhabiting marine plastic debris on the coast of Jeju Island, Korea. The key characteristics of these Korean specimens were consistent with those in the original description of specimens from Hokkaido, Japan, including the presence of tuberculate membranous cuticles between the anterior and posterior dorsal plates, fusion of the posterior epimeral plates I and II, tibia II with a bipectinate seta, tibiae III and IV each with five setae, and a pair of subgenital setae in females. However, two small morphological differences were noted: the distance between the anterior and posterior dorsal plates was shorter than that in Japanese specimens, and the location of dorsal seta-2 was closer to the anterior dorsal plate in Korean specimens. We herein provide detailed illustrations of I. tuberculatus, based on the Korean specimens, with a brief taxonomic comment on the similarities among allied congeneric species. The genus Isobactrus is first reported in Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.208-215
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• 2017

When persistent oil, such as crude oil or Bunker C oil, is spilled at sea, viscosity increases through the weathering process. Equipment that can collect this oil when mixed with floating marine debris is very limited. In this study, devices that can be attached to the outside of existing oil skimmers have been applied to the inside of the main body, to develop an unmanned conveyor belt type floating marine debris and high viscosity oil recovery skimmer, which is composed of a conveyor belt, a sweeper with a forced inflow device, and a collection tank equipped with a buoyant body. The resulting skimmer was operated at a speed of 1.2 knots at a distance of 30 m in a sea area test. It was stable when moving laterally in any direction. An oil recovery performance test was conducted using a portable storage tank, and oil was recovered from a minimum of $7.8k{\ell}/h$ to a maximum of $23.3k{\ell}/h$. Moreover, recovery of $7.7k{\ell}/h$ was obtained in a wave water tank test with floating marine debris such as PET bottles and oil mixed. If the equipment developed in this study was used in the field for oil pollution accidents, it could be expected to contribute to improved response capability. We believe our equipment could be used in further studies to improvement the performance of existing portable oil skimmers.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1854-1864
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• 2015

In order to analyze the pollution characteristics of small plastic debris(SPD) ashore on the shoreline of coastal flow, 12 times of survey were conducted on the Gwanganri beach of Busan for nearly 3 years. The sampled stations on the beach were divided into 11 squared survey sites from St. G1 to G11(see [Fig. 1]) and all of SPD was sorted into 11 items like P1 to P11 according to the kind of plastic materials and products(see