• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.49-57
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• 2016

Aqueous ammonia is widely used in household cleaners, fertilizers and denitrification process. It is usually treated in concentrations from 10 % to 30 %, and release accidents have occurred frequently. In this study, we developed a simplified estimating method and equation to calculate threat zone easily in case of emergency due to release accident of aqueous ammonia. We calculated the consequence distance for toxic endpoints of aqueous ammonia(concentration 10 % ~ 30 %) at different puddle areas($1m^2{\sim}500m^2$) using the ALOHA program. Based on the result, we analyzed the relationship between concentration and puddle area with the threat zone and created the equation.

• Journal of Korean Society of societal Security
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• v.1 no.1
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• pp.63-67
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• 2008

This study focuses on assessing the security ri sk or the terrorism in chemical process industries. This research modifies conventional method for assessing the terrorism risk. The risk assessment method is developed and it is implemented as software to analyze the possibility of terrorism and sabotage. This program includes five steps; asset characterization, threat assessment, vulnerability analysis, risk assessment and new countermeasures. It is a systematic, risk based approach in which risk is a function of the severity of consequences of an undesired event, the likelihood of adversary attack, and the likelihood of adversary success in causing the undesired event. The reliability of the program is verified using a dock zone case. The case dock zone includes a storage farm, a manufacturing plant, an electrical supply utility, a hydrotreater unit, many containers, and administration buildings. This study represents chemical terrorism response technology, the prevention plan, and new countermeasure to mitigate by using risk assessment methods in the chemical industry and public sector. This study suggests an effective approach to the chemical terrorism response management.

• The Journal of Fisheries Business Administration
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• v.52 no.1
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• pp.1-22
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• 2021

This study aims to face common threats from the depletion of fish resources, the decline of production and employment as well as the increase of life risk in East Sea Rim countries, North Korea, South Korea, Japan and Russia due to the Chinese fishing fleets entering East Sea. The recent competition in fishing among fishing vessels and fleets of national origin operating in the East Sea has induced a significant change in the ecological landscape of the fishing fleets cluster while having influenced production and employment in the fishing industries of South Korea and Japan as well as life threat on the fishermen in North Korea. It seems that the population organizational ecological theory can be applied to this change. It can be seen as the isomorphism of the selection process over the exclusive economic zone (EEZ) to avoid the environment in which these North Korean fishing vessels are pushed against the Chinese fleet in the North Korean part of the East Sea. To resolve the fishery disputes or conflict in the common waters in East Sea, first of all, Chinese fishing fleets will be required to put international pressure so as to solve the unfairness of the illegal fishing and overfishing by the International Fishery Organization or the UN violations of the sanctions against North Korea selling fishing rights to China. Although it is not easy for South Korea to cooperate with North Korea in the short term, South Korea will be able to support the fishery infrastructure in North Korea in the mid- to the long-term to prevent the loss of innocent lives for their fishermen and to raise their incomes.

• Journal of Ecology and Environment
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• v.45 no.1
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• pp.62-71
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• 2021

The climate is changing rapidly, and this may pose a major threat to global biodiversity. One of the most distinctive consequences of climate change is the poleward and/or upward shift of species distribution ranges associated with increasing temperatures, resulting in a change of species composition and community structure in the forest ecosystems. The Baekdudaegan mountain range connects most forests from the lowland to the subalpine zone in South Korea and is therefore recognized as one of the most important biodiversity hotspots. This study was conducted to understand the distribution range of vascular plants along elevational gradients through field surveys in the six national parks of the Baekdudaegan mountain range. We identified the upper and lower distribution limits of a total of 873 taxa of vascular plants with 117 families, 418 genera, 793 species, 14 subspecies, 62 varieties, two forms, and two hybrids. A total of 12 conifers were recorded along the elevational gradient. The distribution ranges of Abies koreana, Picea jezoensis, Pinus pumila, and Thuja koraiensis were limited to over 1000 m above sea level. We also identified 21 broad-leaved trees in the subalpine zone. A total of 45 Korean endemic plant species were observed, and of these, 15 taxa (including Aconitum chiisanense and Hanabusaya asiatica) showed a narrow distribution range in the subalpine zone. Our study provides valuable information on the current elevational distribution ranges of vascular plants in the six national parks of South Korea, which could serve as a baseline for vertical shifts under future climate change.

• Proceedings of the KSRS Conference
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• v.1
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• pp.436-440
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• 2006

Diffuse pollution has been considering as a major source of the quality deterioration of water resources. The establishment of riparian vegetation strips of buffers along those areas of water bodies is used to reduce the threat of diffuse pollution. Remote sensing offers a means by which critical areas could be identified, so that subsequent action toward the establishment of riparian zones can be taken. Even though the principal purpose of this research comes from the feasibility of the imagery of KOMPSAT-2 satellite, Landsat TM satellite data, which has 7 bands, are used to characterize the land cover for the study area on the behalf of KOMPSAT-2. This investigation focuses on the assessment of the existing riparian buffer zones for a portion of the upper Geum river watershed from the viewpoint of pollution mitigation by riparian vegetation strip establishment. Through comparing the delineation of riparian buffer zones developed with the existing zones established by the government, we can find the critical distortion points of the existing riparian buffer zone.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.56-64
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• 2015

The personal image information compiled through closed-circuit television (CCTV) will be open to the internet with the technology such as Long-Tail, Mash-Up, Collective Intelligence, Tagging, Open Application Programming Interface (Open-API), Syndication, Podcasting and Asynchronous JavaScript and XML (AJAX). The movie User Created Contents (UCC) connected to the internet with the skill of web 2.0 has the effects of abuse and threat without precedent. The purpose of this research is to develop the institutional and technological method to reduce these effects. As a result of this research, in terms of technology this paper suggests Privacy Zone Masking, IP Filtering, Intrusion-detection System (IDS), Secure Sockets Layer (SSL), public key infrastructure (PKI), Hash and PDF Socket. While in terms of management this paper suggests Privacy Commons and Privacy Zone. Based on CCTV-UCC linked to the above network, the research regarding personal image information security is expected to aid in realizing insight and practical personal image information as a specific device in the following research.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.45-55
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• 2020

Recently, as the awareness of fine dust has increased in Korea, various countermeasures have been suggested. This study examines the current status of fine dust free zones at home and abroad in order to analyze changes in guest space according to the occurrence of fine dust and to find activity patterns. I would like to predict and find implications. The purpose of this study is to forecast demand centering on domestic and foreign countermeasures for dust and domestic industry. In order to secure competitiveness for the smart city in the era of the 4th Industrial Revolution, the research is aimed at proposing a strategic plan to cope with the fine dust that is a threat to urban space. The research method is described in the following order.

• Structural Engineering and Mechanics
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• v.81 no.1
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• pp.39-50
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• 2022

Layer separation (delamination) is an essential threat to fiber-reinforced polymer (FRP) plates under dynamic, static, and fatigue loads. Under compressive load, the growth of delamination will lead to structural instability. The aim of this paper is to present a method using shape memory alloy (SMA) stitches to suppress the delamination growth in a FRP plate and to improve the buckling behavior of the plate with a rectangular hole. The present paper is divided into two parts. Firstly, a closed-form (CF) formulation for evaluating the buckling load of the FRP plate is presented. Secondly, the finite element method (FEM) will be employed to calculate the buckling loads of the plates which serves to validate the results obtained from the closed-form method. The novelty of this work is the development of the closed-form solution using the p-Ritz energy approach regarding the stress-dependent phase transformation of SMA to trace the equilibrium path. For the FEM, the Lagoudas constitutive model of the SMA material is implemented in FORTRAN programming language using a user material subroutines (VUMAT). The model is simulated in ABAQUS/Explicit solver due to the nature of the loading type. The cohesive zone model (CZM) is applied to simulate the delamination growth.

• Maritime Security
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• v.4 no.1
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• pp.83-113
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• 2022

Although China's maritime militia has not been well known despite its long history, it is recently emerging as a serious threat to maritime security, causing neighboring countries' security concerns due to the growing number of maritime disputes with China. In this regard, it is now time to clearly define the true nature of the Chinese maritime militia. A close look at the organization and roles of the Chinese maritime militia reveals that it is an organization that is systematically managed and operated by the Chinese government and the People's Liberation Army of China. Its role is to serve the purpose of "contributing to the protection and expansion of China's marine interests." In addition, the threat factors of the Chinese maritime militia were analyzed by examining the cases of maritime disputes between the Chinese maritime militia and neighboring countries. First, the Chinese maritime militia has implemented the "Gray Zone Strategy." Second, it is a systematic organization supported by the Chinese government and the People's Liberation Army. Third, it is a maritime power that cannot be ignored as the world's largest militia organization. Fourth, it has a strategic flexibility that enables the execution of the dual mission of working for a living such as commercial fishing and serving in the maritime militia. The threats of the Chinese maritime militia are not limited to Southeast Asian countries located in the South China Sea. This is also the case in Korea as the country cannot avoid maritime disputes with China such as the Ieodo issue and the boundary delimitation of the West Sea. Accordingly, this study was focused on presenting a predictable scenario and countermeasures based on the analysis through a scenario technique with respect to the two cases that are most likely to occur in Korea-China relations. Finally, beyond identifying the nature of the Chinese maritime militia, this study takes a further step to share considerations as to how the organization may operate and develop in the future and how we can cope with its moves.

• ETRI Journal
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• v.30 no.1
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• pp.81-88
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• 2008

The security threat posed by worms has steadily increased in recent years. This paper discusses the application of the optimal and sub-optimal Internet worm control via Pontryagin's maximum principle. To this end, a control variable representing the optimal treatment strategy for infectious hosts is introduced into the two-factor worm model. The numerical optimal control laws are implemented by the multiple shooting method and the sub-optimal solution is computed using genetic algorithms. Simulation results demonstrate the effectiveness of the proposed optimal and sub-optimal strategies. It also provides a theoretical interpretation of the practical experience that the maximum implementation of treatment in the early stage is critically important in controlling outbreaks of Internet worms. Furthermore, our results show that the proposed sub-optimal control can lead to performance close to the optimal control, but with much simpler strategies for long periods of time in practical use.