• Ocean and Polar Research
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• v.35 no.3
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• pp.219-228
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• 2013

In Korea, more than 300 oil spill accidents occur every year. Despite the frequency, only a small pool of data is available on the initial effect of oil spill on macrobenthic fauna inhabiting rocky shores. The aim of this study was to analyze the variation of macrobenthic fauna composition and community structure on rocky shores, and understand the impact of oil on rocky shore organisms after the Hebei Spirit oil spill. Field surveys were carried out in five regions dose to the wreck site in January, April and September 2008. Polluted sites after the Hebei Spirit oil spill showed that biological index consistently decreased for 9 months limited to breeding and recruitment of organisms by spilled oil. Macrobenthic community was subdivided into 3 groups by species elimination and differences between density of major dominant species: enriched biota community under a relatively stable environment, the second with relatively low ecological index and the last with poor community. In this study, species number did not clearly reflect the effect of oil on the rare and mobile species. However, mean density, biomass and community structure showed the effect of oil by considering breeding activity, decline in recruitment and variation pattern with time.

• Proceedings of the KSRS Conference
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• v.2
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• pp.981-984
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• 2006

Oil pollution of the ocean is a major environmental problem, especially in its coastal zones. Synthetic aperture radar (SAR) flown on satellites, such as ERS-2 and Envisat, has been proved to be a useful tool in oil spill monitoring due to its wide coverage, day and night, and all-weather capability. The total 120 SAR images containing oil spill over the East China Sea were collected and analyzed, ranging in date from July 23, 2002 to November 11, 2005. After preprocessed, SAR images were segmented by adaptive threshold method. The oil spill images were incorporated into GIS after distinguished from look-like phenomena, finally we presented the oil spills distribution map for the East China Sea. The wide-swath and quick-looks SAR imagery for mapping of oil spill distribution over large marine areas were proved to be useful when full resolution data are not available. After the temporal and spatial distribution of the oil spills were analyzed, we found that most of oil spills were distributed along the main ship routes, which means the illegal discharge by ships, and the occurrence of oil spill detected on SAR images acquired during morning and summer is much higher than during evening and winter.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1475-1490
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• 2021

Detecting oil spill area using statistical characteristics of SAR images has limitations in that classification algorithm is complicated and is greatly affected by outliers. To overcome these limitations, studies using neural networks to classify oil spills are recently investigated. However, the studies to evaluate whether the performance of model shows a consistent detection performance for various oil spill cases were insufficient. Therefore, in this study, two CNNs (Convolutional Neural Networks) with basic structures(Simple CNN and U-net) were used to discover whether there is a difference in detection performance according to the structure of CNN and distribution characteristics of oil spill. As a result, through the method proposed in this study, the Simple CNN with contracting path only detected oil spill with an F1 score of 86.24% and U-net, which has both contracting and expansive path showed an F1 score of 91.44%. Both models successfully detected oil spills, but detection performance of the U-net was higher than Simple CNN. Additionally, in order to compare the accuracy of models according to various oil spill cases, the cases were classified into four different categories according to the spatial distribution characteristics of the oil spill (presence of land near the oil spill area) and the clarity of border between oil and seawater. The Simple CNN had F1 score values of 85.71%, 87.43%, 86.50%, and 85.86% for each category, showing the maximum difference of 1.71%. In the case of U-net, the values for each category were 89.77%, 92.27%, 92.59%, and 92.66%, with the maximum difference of 2.90%. Such results indicate that neither model showed significant differences in detection performance by the characteristics of oil spill distribution. However, the difference in detection tendency was caused by the difference in the model structure and the oil spill distribution characteristics. In all four oil spill categories, the Simple CNN showed a tendency to overestimate the oil spill area and the U-net showed a tendency to underestimate it. These tendencies were emphasized when the border between oil and seawater was unclear.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.283-288
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• 2009

Estimations of oil slick area after M/T Herbei Sprit accident in December 2007 were analyzed using ENVITSAT ASAR(Advanced Synthetic Aperture Radar) microwave and KOMPSAT-2 of high resolution data. Monthly end short-term variations of chlorophyll a concentration before end after M/T Herbei Sprit oil spill accident were also analyzed using SeaWiFS/MODIS ocean color data. The oil slick areas estimated by KOMPSAT-2 and ASAR satellites were 59,456 $m^2$ and 1,168 $km^2$, respectively. The winds before end after oil spill accident were prevailed the northerly and northwesterly winds, and the strength of wind in this accident was stronger than 10 m/sec. In Taean and Anmeon-do, monthly mean chlorophyll a concentrations(6.3 mg/$m^3$ and 3.7 mg/$m^3$) in January 2008 alter the oil spill were higher than those(2.9 mg/$m^3$ and 2.5 mg/$m^3$) in December 2007. Short-term variations of chlorophyll a in these areas were decreased alter one or two weeks of oil spill.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1781-1791
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• 2016

This study aimed to analyze the economic effectiveness on environment improvement project that has been implemented in five fishing grounds of Taean-gun which had been damaged by the Hebei Spirit oil spill accident. In the analysis, first, this study performed the survey on residents perceptions about the environment improvement project. Second, the cost-benefit analysis was carried out to evaluate the economic effectiveness of the project. The survey results of residents perceptions indicated that the damage of oil spill was considerable in the target areas. It also showed that residents wanted to continue the environment improvement project and the levels of project satisfaction were quitely high. The economic results showed that 3 areas(Woong-do, Wang-san, and Dang-mi) would have positive values of NPV and B/C ratio, but the other(Nu-dong) would have negative values. The findings of this analysis could be used as the base data for increasing operational efficiency of future environment improvement projects.

• Korean Journal of Remote Sensing
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• v.33 no.1
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• pp.61-67
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• 2017

The detection of oil spills using radar image has been studied extensively. However, most of the proposed techniques have been focused on improving detection accuracy through the advancement of algorithms. In this study, research has been conducted to improve the accuracy of oil spill detection by improving the quality of radar images, which are used as input data to detect oil spills. Thresholding algorithms were used to measure the image improvement both before and after processing. The overall accuracy increased by approximately 16%, the producer accuracy increased by 40%, and the user accuracy increased by 1.5%. The kappa coefficient also increased significantly, from 0.48 to 0.92.

• Journal of Ocean Engineering and Technology
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• v.25 no.3
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• pp.90-95
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• 2011

On April 20, 2010, a well control event allowed hydrocarbon (oil and gas) to escape from the Macondo well onto Deepwater Horizon (DWH), resulting in an exploration and fire on the rig. While 17 people were injured, 11 others lost their lives. The fire continued for 36 hours until the rig sank. Hydrocarbons continued to flow out from the reservoir through the well bore and blowout preventer (BOP) for 87 days, causing an unprecedented oil spill. Beyond Petroleum (BP) and the US federal government tried various methods to prevent the oil spill and to capture the spilled oil. The corresponding responses were very challenging due to the scale, intensity, and duration of the incident that occurred under extreme conditions in terms of pressure, temperature, and amount of flow. On July 15, a capping stack, which is another BOP on top of the existing BOP, was successfully installed, and the oil spill was stopped. After several tests and subsea responses, the well was permanently sealed by a relief well and a bottom kill on September 19. This paper analyzes the subsea responses and engineering efforts to capture the oil, stop the leaking, and kill the subsea well. During the investigation and analysis of subsea responses, information was collected and data bases were established for future accident prevention and the development of subsea engineering.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.910-914
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• 2010

A collision between a barge and an oil tanker of Hebei Spirit caused the release of an estimated 12,547 tons of light crude oil into the Yellow Sea off the west coast of Taean-gun, Korea on December 7, 2007. This study was aimed to evaluate exposure conditions and acute health effects in soldiers participating in the Hebei Spirit oil spill cleanup activities and the association between these and the nature of the work and use of protection devices. The sample comprised 2,624 soldiers stratified by working area and number of working days. We divided working area into the coast of Taean-gun(highly polluted area) and other areas affected by Hebei Spirit oil spill. And we divided number of working days into 1-7 days, 8-14 days, 15-21 days and above 22 days. Data were obtained via a structured, self-administered questionnaire and included information on working area, type of working, number of working days, use of protective materials, and acute health effects. Acute health effects were classified into 5 groups: neurological, respiratory, dermatologic, ophthalmic and other symptoms. Data analysis was performed using unconditional logistic regression used to compute odds ratios and 95% confidence intervals. On logistic regression analysis, working on the coast of Taean-gun was significantly associated with increased risk of acute health problems: headache, dizziness, nausea, general fatigue, insomnia, flushed face, sore throat, dry throat, runny nose, cough, sputum, skin irritation, sore eyes, injection of conjunctiva, tear, and low back pain. Furthermore soldiers working more than 21 days were significantly associated with increased risk of acute health problems: insomnia, flushed face, sore throat, runny nose, cough, sputum, tear, low back pain and fever. Accordingly, the exposure to the oil and the subsequent cleanup efforts were suggested to inflict acute health problems on soldiers participating in the Hebei Spirit oil spill cleanup activities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.455-461
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• 2017

The Hebei Spirit oil spill incident occurred in December 7, 2007 and caused approximately $12,547k{\ell}$ of crude oil spillage along 370km off the west coast of Korea. Due to the astronomical and irrecoverable damage to the marine ecosystems and the overall living standards of the residents, the oil spill incident has been notoriously named as the "worst oil spill incident" occurred in Korea. Nevertheless, though almost a decade has passed since the tragic incident in Korea, it appears that compensation and recovery efforts seem not close to satisfaction and the local residents are still struggling with various negative impacts incurred by the incident because of critical cleavage among the interests of the relevant parties to the incident. In this paper, the analysis of Hebei Spirit oil spill incident regarding two aspects was carried out; First, meticulously analyze the practical and statistical data of the incident to precisely examine the fundamental causes for its occurrence to further prevent the reoccurrence of such disastrous incident; and the second, comprehensively inspect reasons for the protracted and inefficient damage recovery and victim-oriented compensation. To be specific, this study observed the levels of compensation against damages from the incident, and the adequacy of it in terms of ultimately and inclusively addressing financial, social and ecological aspects based primarily upon the legal verdicts, and statistical and empirical surveys.

• Journal of KIISE:Databases
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• v.37 no.5
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• pp.228-237
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• 2010

Although conventional index structures provide various nearest-neighbor search algorithms for high-dimensional data, there are additional requirements to increase search performances as well as to support index scalability for large scale data. To support these requirements, we propose a distributed high-dimensional indexing structure based on cluster systems, called a Distributed Vector Approximation-tree (DVA-tree), which is a two-level structure consisting of a hybrid spill-tree and VA-files. We also describe the algorithms used for constructing the DVA-tree over multiple machines and performing distributed k-nearest neighbors (NN) searches. To evaluate the performance of the DVA-tree, we conduct an experimental study using both real and synthetic datasets. The results show that our proposed method contributes to significant performance advantages over existing index structures on difference kinds of datasets.