• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.642-647
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• 2011

In order to analyze the influence of floating marine debris (FMD) in the East China Sea (ECS), a sighting survey was conducted from July 1st to July 14th, 2009 navigating about 966 km using a training vessel "Kaya (1,737 ton)" of Pukyong National University. The sampled zones are divided into 5 transect by observation day during the survey days and again specified with 45 segments per unit hour on the survey routes. The results of distribution of FMD are as follows: 1. The quantities of FMD at the central China Sea(CE) and northern part of Taiwan(NT) were found as total mean of 90.8 ea/hr, 56.7 ea/hr, respectively, and also 36.8 ea/hr, western part of Kyushu district(WJ), 10.7 ea/hr, 8.0 ea/hr, western(OK1) and northern part(OK2) of Okinawa, respectively. 2. Temporal variation of FMD is represented by depicting the sinusoidal curve as shape as tide in CE and OK1. 3. The higher sea surface temperature (SST) is as likely as if Kuroshio current exists strongly, the less quantities are decreased. On the other hand, the coastal zone of ECS and near of Yellow Sea are increased by lower SST.

• Journal of Distribution Science
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• v.18 no.1
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• pp.15-26
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• 2020

Purpose: This study is to analyze the image classification using Convolution Neural Network and Transfer Learning for Jeju Island and to suggest related implications. As the biggest tourist destination in Korea, Jeju Island encounters environmental issues frequently caused by marine debris along the seaside. The ever-increasing volume of plastic waste requires multidirectional management and protection. Research design, data and methodology: In this study, the deep learning CNN algorithm was used to train a number of images from Jeju clean and polluted beaches. In the process of validating and testing pre-processed images, we attempted to explore their applicability to coastal tourism applications through probabilities of classifying images and predicting clean shores. Results: We transformed and augmented 194 small image dataset into 3,880 image data. The results of the pre-trained test set were 85%, 70% and 86%, and then its accuracy has increased through the process. We finally obtained a rapid convergence of 97.73% and 100% (20/20) in the actual training and validation sets. Conclusions: The tested algorithms are expected to implement in applications for tourism service distribution aimed at reducing coastal waste or in CCTVs as a detector or indicator for residents and tourists to protect clean beaches on Jeju Island.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.4
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• pp.229-239
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• 2019

A model of landslides is developed using the shallow water equations to simulate time-dependent performance of landslides. The shallow water equations are derived using the (b, s) coordinate system which can be applied in both river and ocean. The finite volume scheme employing the HLL approximate Riemann solver and the total variation diminishing (TVD) limiter is applied to deal with the numerical discontinuities occurring in landslides. For dam-break water flow and debris flow, numerical results are compared with analytical solutions and experimental data and good agreements are observed. The developed landslide model is successfully applied to predict subaerial and submarine landslides. It is found that the subaerial landslide propagates faster than the submarine landslide and the speed of propagation becomes faster with steeper bottom slope and less bottom roughness.

• Journal of the Korean Geographical Society
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• v.47 no.4
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• pp.474-489
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• 2012

Last review papers on Korean geomorphology and physical geography had been published in 1997 and 2000 respectively. A proposal to publish a book on Korean geomorphologists' achievement resulted in series of review papers in Journal of the Korean Geomorphological Association. This article aims to summarize these papers and introduce their findings to foreign scholars. On remarkable achievement is a fierce debate on the effectiveness of traditional mountain concept to explain the shape of Korean peninsula, which made the public's understanding of geomorphology widen to the general public. Reflecting public demands, concerns for the effects of coastal facilities on coastal erosion and conservation mind and scientific researches for the coastal sand dunes have increased so much. Geomorphological hazards such as debris flow attracted many concerned scientists, and geotourism-related papers in scientific journals increased thanks to the designation of first geopark in Korea. Research papers submitted to the famous foreign academic journals are increasing in numbers these days.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.37-46
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• 2009

Typhoon Rusa in 2002 was recorded as causing the biggest damage due to flood in our country. With the enormous damage to the land, the flood was totally discharged to the open sea. As a result, in the coastal area, the discharging of a river had a big influence in comparison to the scale of the coastal area, which suffered damaged due to the discharging of the river. As it cleared the land, the load was totally discharging into the sea, where it caused various problems due to its influence on the ecosystem. These included changes to the environment, like a difference in salinity and the inflow of a land load. Therefore, in this study, a Lagrangian particle tracking model was constructed using a flow model capable of solving the behavior of a river plume, supposing Sachon Bay. It is performed the research able to tendency-like valuation and reappearance about real event. The result was that the model was well approximated the sea area tendency and the river plume of the specific event.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.444-455
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• 2009

Great concerns on geotechnical risk & hazard assessment have been increased due to human and economic damage by natural disasters with recent global climate changes. In this paper, geotechnical problems in particular, landslides which is interested in European countries and North America, were mainly discussed. For these, 18 key topics on geotechnical risk and hazards which had been discussed at the LARAM 2008 workshop in Italy were analyzed after grouping by subjects. Main topic contents consisted of applications such as field measurement, early warning systems, uncertainty analysis of parameters using radar, optical data and statistical theory and so on. And the problems related to analysis of vulnerability and deformation due to earthquakes, investigation of gas zone using seismic reflection data in a landslide area, risk quantification and hazard assessment of landslide movements and multi-dimensional analysis for stability of complex slopes were attracted. Also, there were studies on risk matters of cultural heritage, the blockglide of clayey ground, simulations of debris flows based on GIS, quantification of the failure processes of rock slopes, a meshless method for 3D crack modelling, and finally risk assessment for cryological processes due to global warming.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.29-32
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• 2007

Damages induced typhoons have been increased and super-typhoons have occurred frequently. In our study, we propose a storm risk assessment technique based on CFD for the industrial structures and equipment located in the coastal regions. Inflow wind speeds are obtained through the information of geography and meteorology in considering regions before pressures of wind-environment and structures corresponding to different winds are calculated with wind speed multiplier and pressure coefficient. The results are applicable to evaluate a warning wind speed or regions vulnerable to debris in a considering region and to examine the safety of structures and their exteriors.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.242-248
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• 2014

We have five soil series of pan soils in South Korea out of 391 series: Gangreung, Bugog, Yeongog, Jangweon, and Pogog. Productivity decreases in pan soils as pan horizons impede percolation and capillary rise of water and interrupt root extension. This study was performed to investigate pedogenic processes of pan soils mainly located in footslope and river terrace by analyzing physicochemical properties and soil micro-morphology. Korean pan soils belong to Alfisols, Ultisols, or Inceptisols and have udic or aquic soil moisture regime, mesic temperature regime, and mixed mineral substances. Texture of pan horizons selected for the present study was mainly silty clay loam with clay contents ranging from 26.3 to 45.3%. Bulk density of the pan horizons ranged from 1.4 to $2.1Mg\;m^{-3}$ and their soil structure were subangular or angular structure. In terms of micro-morphological structure, Bt horizon of Gangreung series was formed as platy and striated b-fabric structure possibly affected by uplift of coastal terrace following clay sedimentation by flood. Jangweon series showed micro-morphology of massive structure and crystallic b-fabric as macropores between coarse debris established by debris fall in slope were filled with silt-sized particles. The Bt horizons having massive structure and striated b-fabric in Yeongog, Pogog, and Bugog series implies that those horizons experienced horizontal mass flow after clay accumulation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.98-103
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• 2004

Recently, a New Great Harbour Bridge between Mokpo City and Koha Island is planned to be built across Mokpo Inner Harbour, and Namak New Town is under construction adjacent to Mokpo. Citizels' concorn of and participation in 「Campaign for Shaping Mokpo into Beautiful Seaport」 are necessary to match the view of Mokpo harbour with natural scenery beautifully and with marine environment harmoniously. Citizens'ㄹ levels of consciousness of coastal and marine environment were ascertained through questionnaire surveys of local citizenry attitudes and opinions, and citizenry action plans for the conservation of coastal and marine environments around Mokpo harbour are suggested on the basis of the results of questionnaire surveys. Citizens' voluntary participations in local policy for the control of marine wastes production and in a campaign for the collections of marine debris and wastes around beaches and coastal areas are required. The operation of municipal sewage treatment plants is to be performed effectively and efficiently, and to be monitored and evaluated periodically by the general public, the local federation for environmental movement or NGO. The development and performance of marine environmental education programs and an enlightenment campaign for environment preservation are to be incessantly done in cooperation with local residents. Only when local government of Mokpo collects the public opinions and continues to shape Mokpo into international beautiful seaport in the direction of a reflex of public opinion, coastal and marine environment around Mokpo harbour can be kept in good condition with citizens' positive participation in citizenry long-term practical action plans for environment conservation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.372-377
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• 2019

Recently, as the global problem of marine debris and marine plastics is getting serious, various ways to solve them have been proposed, and the use of the biodegradable fishing gear is proposed as an alternative. Currently, 13 types of biodegradable fishing gears are available, but their penetration rate is only 8.7%. However, the need for the use of the biodegradable fishing gear is growing as awareness of protecting marine ecosystems is growing. Therefore, in this study, the economic effects of the expansion of biodegradable fishing gear distribution in Korea's coastal areas were analyzed through the conservation of marine ecosystems, augmentation of fisheries resources, and augmentation of fishing efficiency. According to the analysis, the economic effects of 52,795 million won, 105,590 million won, and 158,385 million won was generated as the distribution of biodegradable fishing gear were expanded to 10%, 20% and 30% across all gill net and trap.