• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.45-59
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• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Cartoon and Animation Studies
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• s.37
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• pp.361-392
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• 2014

Regarding works that express objects realistically in painting, Gustave Courbet advocated realism in the mid-19th century, France, resisting the then academist style of painting, and works in realist style were produced in earnest by painters such as H. Daumier or Jean F. Millet, who went along with him. Later, realism has expanded into the realm of general literature, including fine art, which has had profound impacts on works of art and literary works. In comics, too, in the same historical context as a form of painting, realistic comics began to be produced by painters or cartoonists at the time. These realism comics are those dealing with stories based on facts, and in terms of contents, objective description and representation of the social realities of the times is one of the most important objectives, but it could not be concluded that in their visual aspect, that is, that of expressing the objects, they were realistic. In the meantime, a graphic novel was born, which was the intermediate form between comics and novels around the United States and Europe since the 1980s. Graphic novels appeared in forms and styles with strong literary and artistic values in the comics market in the U.S. which was full of the superhero genre (comics around heroes), and their major characteristics are very realistic expressions in terms of contents and visual aspect. They are complex and delicate and even have artistic, literary values as if readers read a fiction or literary work of which its narrative structures or pictures are produced with graphics. The characteristics of realistic expressions shown in graphic novels are very different from the previous works of comics. It is noteworthy that they began to be acknowledged as works of art like painting or illustration, thanks to their features of strongly individual auteurist painting style, a fairly high degree of completion of the works, and creative and experimental expression techniques or methods, instead of following the fashion of the times. In recent years, in South Korea, Hollywood blockbuster films have been released one after another and become box office hits, there are increasing interest and demand for the original graphic novels. Accordingly, many original graphic novels have been translated and started to be sold, and keeping pace with this global flow of fashion, some writers in Korea began to produce works of graphic novels. However, to look into the domestic works produced claiming to be graphic novels, there are various opinions on their format and authenticity. In this sense, this study focused on Ga-ya Kwon's Namhansanseong, one the representative works of Korean style graphic novels, and in particular, it attempted to analyze their characteristics and commonalities focusing on the visual aspect of realistic expressions of objects. It is expected that there would be an opportunity to seek for ways so that Korean style graphic novel can be further developed as a genre of comics, with competitiveness by looking back on the identity and present state of domestic graphic novels and developing and applying Korea's original subject matters differentiated from those of graphic novels in the U.S., Europe or Japan through this study. In addition, it is desired that they will be a new energizer for the stagnant domestic comics market.

• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.191-207
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• 2021

Up to this day, mobile communications have evolved rapidly over the decades, mainly focusing on speed-up to meet the growing data demands of 2G to 5G. And with the start of the 5G era, efforts are being made to provide such various services to customers, as IoT, V2X, robots, artificial intelligence, augmented virtual reality, and smart cities, which are expected to change the environment of our lives and industries as a whole. In a bid to provide those services, on top of high speed data, reduced latency and reliability are critical for real-time services. Thus, 5G has paved the way for service delivery through maximum speed of 20Gbps, a delay of 1ms, and a connecting device of 106/㎢ In particular, in intelligent traffic control systems and services using various vehicle-based Vehicle to X (V2X), such as traffic control, in addition to high-speed data speed, reduction of delay and reliability for real-time services are very important. 5G communication uses high frequencies of 3.5Ghz and 28Ghz. These high-frequency waves can go with high-speed thanks to their straightness while their short wavelength and small diffraction angle limit their reach to distance and prevent them from penetrating walls, causing restrictions on their use indoors. Therefore, under existing networks it's difficult to overcome these constraints. The underlying centralized SDN also has a limited capability in offering delay-sensitive services because communication with many nodes creates overload in its processing. Basically, SDN, which means a structure that separates signals from the control plane from packets in the data plane, requires control of the delay-related tree structure available in the event of an emergency during autonomous driving. In these scenarios, the network architecture that handles in-vehicle information is a major variable of delay. Since SDNs in general centralized structures are difficult to meet the desired delay level, studies on the optimal size of SDNs for information processing should be conducted. Thus, SDNs need to be separated on a certain scale and construct a new type of network, which can efficiently respond to dynamically changing traffic and provide high-quality, flexible services. Moreover, the structure of these networks is closely related to ultra-low latency, high confidence, and hyper-connectivity and should be based on a new form of split SDN rather than an existing centralized SDN structure, even in the case of the worst condition. And in these SDN structural networks, where automobiles pass through small 5G cells very quickly, the information change cycle, round trip delay (RTD), and the data processing time of SDN are highly correlated with the delay. Of these, RDT is not a significant factor because it has sufficient speed and less than 1 ms of delay, but the information change cycle and data processing time of SDN are factors that greatly affect the delay. Especially, in an emergency of self-driving environment linked to an ITS(Intelligent Traffic System) that requires low latency and high reliability, information should be transmitted and processed very quickly. That is a case in point where delay plays a very sensitive role. In this paper, we study the SDN architecture in emergencies during autonomous driving and conduct analysis through simulation of the correlation with the cell layer in which the vehicle should request relevant information according to the information flow. For simulation: As the Data Rate of 5G is high enough, we can assume the information for neighbor vehicle support to the car without errors. Furthermore, we assumed 5G small cells within 50 ~ 250 m in cell radius, and the maximum speed of the vehicle was considered as a 30km ~ 200 km/hour in order to examine the network architecture to minimize the delay.