• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.515-530
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• 2013

The results of investigations into marine incidents have become an important basis in determining not only possible causes, but also the extent of negligence between the perpetrator and victim. However, marine incidents occur under special circumstances i.e. the marine environment, and this leads to difficulties in identifying causes due to problems in scene preservation, reenactment and acquisition of witnesses. Given the aforementioned characteristic of marine incidents, the International Convention for the Safety of Life at Sea (SOLAS) has adopted mandatory regulations on the carriage of Voyage Data Recorders (VDRs) and Automatic Identification Systems (AIS) for ships of a certain gross tonnage and upwards, so as to reflect recent developments in radio communication and marine technology. Adopted to provide an international standard for investigations and to promote cooperation, the Code of the International Standards and Recommended Practices for a Safety Investigation into a Marine Casualty or Marine Incident (Casualty Investigation Code) recommends member states to build capacity for analysis of VDR data. Against this backdrop, this paper presents methods for efficient investigations into the causes behind marine incidents based on data analysis of VDR, which serves as the black box of ships, as well as digital forensic techniques.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.166-171
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• 2010

In this paper, the front-end of a digital receiver with a 25 kHz carrier frequency, 5 kHz symbol rate, and any excess-bandwidth is designed using two basic facts. The first is known as the uniform sampling theorem, which states that the sampled sequence might not suffer from aliasing even if its sampling rate is lower than the Nyquist sampling rate if the analog signal is a bandpass one. The other fact is that if the sampling rate is 4 times the center frequency of the sampled sequence, the front-end processing complexity can be dramatically reduced due to the half of the sampled sequence to be multiplied by zero in the demixing process. Furthermore, the designed front-end is simplified by introducing sub-filters and sub-sampling sequences. The designed front-end is composed of an A/D converter, which takes samples of a bandpass filtered signal at a 20 kHz rate; a serial-to-parallel converter, which converts a sampled bandpass sequence to 4 parallel sub-sample sequences; 4 sub-filter blocks, which act as a frequency shifter and lowpass filter for a complex sequence; 4 synchronized switches; and 2 adders. The designed front-end dramatically reduces the computational complexity by more than 50% for frequency shifting and lowpass filtering operations since a conventional front-end requires a frequency shifting and two lowpass filtering operations to get one lowpass complex sample, while the proposed front-end requires only four filtering operation to get four lowpass complex samples, which is equivalent to one filtering operation for one sample.

• Strategy21
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• s.43
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• pp.57-88
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• 2018

Security situations are fundamentally and rapidly changing on the Korean Peninsula. Above all, as North Korea(NK) is heightening its nuclear and missile capabilities, Republic of Korea(ROK) is facing an existential threat. At the same time, as China's economic, diplomatic and military power is quickly rising, the balance of power is shifting and strategic competition between the Unite States(US) and China is accelerating in the Asia-Pacific region. Under the pressure of development of these situations, ROK seems to face allegedly the most serious crisis in its national security since the end of the Korean War. In the current grim geopolitical situation, maritime security may become the most difficult security challenge for ROK in the years to come. The purpose of this paper is to compare major changes in maritime security affairs of the ROK during last twenty years from 1998 until now(2018). 1998 was when this journal 『Strategy 21』 was published for the first time by the Korea Institute for Maritime Strategy. Then, this paper tries to identify challenges and risks with which this country has to deal for its survival and prosperity, and to propose some recommendations for the government, the Navy, and the Coast Guard as they are responsible for the maritime security of the country. The recommendations of this paper are as follows: strengthen ROK-US alliance and expand security cooperation with regional powers in support of the maintenance of the current security order in the region; building-up of maritime security capacity in preparation for crisis on the maritime domain with the navy targeting to acquire 'a non-nuclear, balance-of-terror capability, to improve interoperability with the Coast Guard based on 'a national fleet,' and to actively pursue innovation in naval science and technology. Finally, this paper proposes that naval capability the country needs in another twenty years depends on how effectively and rigorously the navy put its utmost efforts towards building 'a strongest navy' today.

• Strategy21
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• s.41
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• pp.108-152
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• 2017

This paper aims to analyze hegemonic competition and the role of naval power. To this end the paper is composed of four chapters titled introduction, the role of naval power in the hegemonic competition, the role of naval power in the East Asia, and the lessons and implications for the Korean Peninsula. Since the modern era, the hegemonic competition in the East Asian region has been the intrusion and struggle process between the world system and the East Asian regional system, and the ocean between these two systems has become the goal and means of supremacy(hegemony). Currently, the hegemonic competition between the US and China consists of systemic competition at the global level and marine competition at the regional level. When South Korea is forced to make strategic choices in the course of the US-China hegemonic competition, naval power will be the first factor to be considered. The ROK is asymmetrically maintaining a deep dependency relationship with the United States in terms of security and China in relation to the economy. And while the ROK's national economic power is acquired from the ocean, the ROK's military power is imbalanced because it is centered on the ground forces. These international relations and asymmetric-unbalanced resources distribution will not be able to effectively cope with the hegemonic competition between the US and China in the future, and will limit Korea's strategic choice. Since naval power and forces are the prerequisites for the hegemonic competition or the maintenance of supremacy we must construct balanced naval forces(naval power) that are not subordinate to the ground forces at the national strategic level for the future of the country.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.626-637
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• 2013

We measured the grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS) and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) of intertidal surface sediment collected from 11 islands (62 stations) in the southern region of Jeollanam Province. The objective of this research was to evaluate the organic matter and trace metals contaminations of sediments from coastal island tidal flats. Surface sediment texture was characterized as follows: mud, sandy silt, muddy sand, and slightly gravelly sand facies. The finer sediments are mainly dominated in the northern part of each island. The concentrations of IL, COD, AVS and some trace metals (Al, Fe, Zn, Cr, Cu, and Hg) were higher in the northwestern part of Wan Island and the area between Gogeum and Sinji Islands, and were associated with relatively finer sediment, as compared to other locations. The concentrations of Mn, Pb, Cd, and As were higher in the northwestern and southeastern parts of Geoguem and Pyungil Islands, but were not correlated with mean grain size. Based on sediment quality guidelines (SQGs), the concentrations of trace metals were lower than the values of effect range low (ERL), used in United States, and threshold effects level (TEL), used in Korea, with exception of As. Similarly, the intertidal sediments were moderately contaminated with As, based on the the enrichment factor (EF) and the geoaccumulation index ($I_{geo}$). The high concentration of As in intertidal sediments from this study region may be due to the input of naturally or artificially contaminated submarine groundwater, contaminated waste from seaweed aquaculture operations and/or land-based seaweed processing facilities. Further studies are needed to identify the sources of As in this study region, and to determine the effects of As contamination on coastal ecosystem.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.447-452
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• 2010

A very good seakeeping vessel is able to operate effectively even in high sea states and also the passengers and the cargos are ensured in good conditions. The motions of a high speed boats are highly influenced by speed and dynamic forces even in encounter frequencies so that the assessment of seakeeping ability of the design craft in an early stage needs to be calculated for all three motions and for all ralative wave headings. In this paper, it concludes that RAO and RMS values of the catamaran's 3 motion are calculated according as the variation of Beafort scales and ship's speed. The ship motion response of the catamaran based on the RAO and RMS by encounter angles and speed was calculated.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.303-316
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• 2009

Benthic macroinvertebrate communities collected from eight different streams in South Korea were analyzed to compare community and biological indices across different levels of water pollution. The Self-Organizing Map (SOM) was utilized to provide overview on association of the proposed indices. The sample sites were accordingly clustered according to the gradient of pollution on the SOM. While the general trends of the indices were commonly observable according to different levels of pollution, the detailed differences among the indices were also illustrated on the SOM. The conventional diversity and evenness indices tended to be high even though the water quality state was poor representing relatively weak gradient at polluted sites, while the index presenting the saprobic degree such as family biotic index showed the stronger gradient at the polluted area and was robust to present the gradient. Our results also confirmed the general characterization of two indices: The Shannon index is more strengthened by the number of species occurring at the sample sites, while the Simpson index is more influenced by the degree of evenness among the species. The patterning based on the SOM was efficient in comparatively characterizing the proposed indices to present ecological states and water quality.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.324-334
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• 2010

This investigation was carried out to research on the actual states for bycatch and discards of catches caught by funnel net from December, 2007 to June, 2010. Fishing grounds were Manheung-dong and Ocheon-dong in the coastal waters of Yeosu. The number of the investigation was 21 in Manheung-dong and 7 in Ocheon-dong fishing ground. In Manheung-dong, the species of catches were 26 of fish, 6 of cephalopod and 5 of crustacean. In Ocheon-dong, the species of catches were 25 of fish, 6 of cephalopod and 4 of crustacean. In the two all fishing grounds, the largest amount of species was revealed as gray mullet. Among these catches, the number of non marketable species that were classified and discarded ones, were 9 in Manheung-dong and 7 in Ocheon-dong. Also, among the marketable species which were small entity or too tiny catches to commercialize and not fresh ones were discarded. The proportion that they dominate in the whole catches was 37.1% in the number of catches and 5.4% in the weight of catches in Manheung-dong, and 6.9% in the number of catches and 0.3% in the weight of catches in Ocheon-dong. In case of Manheung-dong, the monthly discarding proportion was the highest with 59.4% in the number of catches in may and 17.6% in the weight of catches in November, and in case of Ocheon-dong, the both of them were the highest in February, with 28.0% in the number of catches and 5.1% in the weight of catches.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.378-391
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• 2019

The objective of this study is to establish a direction for smart aquaculture technology development in the Republic of Korea through patent analysis and a demand survey of experts and fishermen. The patent analysis was conducted using Wisdomain for patents in the Republic of Korea, the United States of America, Europe, Japan, and China from 2005 to 2016. This study conducted an analytic hierarchy process (AHP) survey of experts in the fields of fishery, marine, and ICT among others. Furthermore, it carried out a demand survey of 85 fishermen in Jeonnam and Jeju. The smart aquaculture technology market has moderately grown in the Republic of Korea until recently, and it is expected to expand further because of the expansion of national investment in the smart aquaculture field. The priority evaluation results for developing smart aquaculture technology show that land-based aquaculture has a higher priority than sea-based aquaculture. Of the fishermen that responded, 84% said that they need to introduce smart aquaculture technology to solve problems in the supply and demand of manpower, labor cost, and maintenance expenses. The direction of development should lie in developing biological and environment-based standard aquaculture models to spread high-tech systems and vitalize the aquaculture industry. This requires continual training of human resources in the smart aquaculture field.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.49-58
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• 2014

The illegal fishery act committed Chinese fishing vessels have not been stopped and Korea Coast Guard(KCG) has been injured or killed by chinese fishing forces, even though the Korean Government has been trying to control the illegal fishery and repeated violent act committed by Chinese fishing vessels in our Exclusive Economic Zone. Moreover, some problems in relation to the control process of KCG to suppress the illegal foreign fishing vessels has been exposed in spite of extensive efforts of Korean Government. Improper law enforcement of KCG in relation to foreign fishing vessels would cause international dispute between related states, although the control process to the illegal fishing vessels at sea is in a way of due law enforcement process forming a State's power. To this end, this paper examines the problems raised during the control process which is including the visit and inspection of illegal Chinese fishing vessels and law enforcement process exercised by KCG and presents practical solutions through analyzing the related materials, professional's opinion and recent cases.