• Journal of the Korean Geotechnical Society
• /
• v.40 no.4
• /
• pp.169-178
• /
• 2024

While stable mid- to large-scale underground hydrogen storage infrastructures are needed to meet the rapidly increasing demand for hydrogen energy, evaluating the safety of explosion vibrations in adjacent buildings is becoming important because of gas explosions in underground hydrogen storage facilities. In this study, a numerical analysis of vibration safety effects on nearby building structures was performed assuming a hydrogen gas explosion disaster scenario in a low-depth underground hydrogen storage facility. A parametric study using a meta-model was conducted to predict changes in ground dynamic behavior for each combination of ground properties and to analyze sensitivity to geotechnical influencing factors. Directly above the hydrogen storage facility, the unit weight of the ground had the greatest influence on the change in ground vibration due to the explosion, whereas, farther away from the facility, the sensitivity of dynamic properties was found to be high. In addition, in evaluating the vibration stability of ground building structures based on the predicted ground vibration data and blasting vibration tolerance criteria, in the case of large reinforced concrete building structures, the ground vibration safety was guaranteed with a separation distance of about 10-30 m.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.5
• /
• pp.725-733
• /
• 2024

This study aims to develop an artificial intelligence-based model for predicting the causes of chemical accidents, utilizing data on 865 chemical accident situations and cases provided by the Chemical Safety Agency under the Ministry of Environment from January 2014 to January 2024. The research involved training the data using six artificial intelligence models and compared evaluation metrics such as accuracy, precision, recall, and F1 score. Based on 356 chemical accident cases from 2020 to 2024, additional training data sets were applied using chemical accident cause investigations and similar accident prevention measures suggested by the Chemical Safety Agency from 2021 to 2022. Through this process, the Multi-Layer Perceptron (MLP) model showed an accuracy of 0.6590 and a precision of 0.6821. the Multi-Layer Perceptron (MLP) model showed an accuracy of 0.6590 and a precision of 0.6821. The Logistic Regression model improved its accuracy from 0.6647 to 0.7778 and its precision from 0.6790 to 0.7992, confirming that the Logistic Regression model is the most effective for predicting the causes of chemical accidents.

• Clean Technology
• /
• v.30 no.3
• /
• pp.220-227
• /
• 2024

As the demand for lithium-ion batteries with high capacity and high energy density has rapidly increased, silicon anodes (theoretical capacity = 3,570 mA h g^-1) have garnered attention as potential replacements for conventional graphite anodes (theoretical capacity = 372 mA h g^-1). However, silicon anodes suffer from severe volume expansion (~360%) during lithiation, low ionic conductivity (10^-14 ~ 10^-13 cm² S^-1), and low electrical conductivity (10^-2 S cm^-1), resulting in poor cycling and rate performance. To address these issues, this study synthesized core@shell-structured silicon@carbon nanoparticles (Si@C NPs) via a one-pot spray pyrolysis process using Pluronic-F127. Pluronic-F127 in the spray solution contributes to the synthesis of nanoparticles by preventing the formation of silicon nanoparticle/dextrin agglomerates and by undergoing pyrolysis simultaneously. Additionally, dextrin derived amorphous carbon was coated on the surface of the silicon nanoparticles to act as an electron transport pathway within the anodes and enhance the electrical contact between the silicon nanoparticles. The Si@C NPs exhibited a discharge capacity of 1,912 mA h g^-1 after 50 cycles at 1.0 A g^-1 and high rate capabilities (discharge capacity of 1,493 mA h g^-1 at 3.0 Ag^-1). The silicon@carbon composite nanoparticle synthesis strategy based on the spray pyrolysis process presented in this study is expected to offer a new direction for improving the performance of silicon anode materials.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.1
• /
• pp.57-72
• /
• 2018

Time series analysis of tower flux measurement can be used to build quantitative evidence for the achievement of climate-smart agriculture (CSA). In this study, we have assessed the first objective of CSA (regarding ecosystem productivity and efficiency) for rice paddy-dominated heterogeneous farmland. A set of quantitative indicators were evaluated by analysing the time series data of carbon, water and energy fluxes over the Haenam farmland site in Korea (HFK) during the rice growing seasons from 2003 to 2015. Four different varieties of rice were cultivated during the study period in chronological order of Dongjin No. 1 (2003-2008), Nampyung (2009), Onnuri (2010-2011), and Saenuri (2012-2015). Overall at HFK, gross primary productivity (GPP) ranged from 800 to $944g\;C\;m^{-2}$, water use efficiency (WUE) ranged from 1.91 to $2.80g\;C\;kg\;H_2O^{-1}$, carbon uptake efficiency (CUE) ranged from 1.06 to 1.34, and light use efficiency (LUE) ranged from 0.99 to $1.55g\;C\;MJ^{-1}$. Among the four rice varieties, Dongjin No. 1-dominated HFK showed the highest productivity with higher WUE and LUE, but comparable CUE. Considering the heterogeneous vegetation cover at HFK, a rule of thumb comparison suggested that the productivity of Dongjin No1-dominated HFK was comparable to those of monoculture rice paddies in Asia, whereas HFK was more efficient in water use and less efficient in carbon uptake. Saenuri-dominated HFK also produced high productivity but with the growing season length longer than Dongjin No.1. Although the latter showed better traits for CSA, farmers cultivate Saenuri because of higher pest resistance (associated with adaptability and resilience). This emphasizes the need for the evaluation of other two objectives of CSA (i.e. system resilience and greenhouse gas mitigation) for complete assessment at HFK, which is currently in progress.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.8
• /
• pp.1302-1310
• /
• 2004

The purpose of this study was to investigate whether a web-based nutrition counseling could lead to beneficial outcomes in food intake and serum lipids of patients with hyperlipidemia. Forty hyperlipidemic patients, twenty of them were hypercholesterolemia and the other twenty were hypertriglyceridemia, participated in a web-based nutrition counseling program. At the first nutrition counseling, the patients were counselled through interview and then follow up nutrition counseling was accomplished four times during eight weeks through a web-based internet program. Various markers of disease risk including anthropometric indices, food intakes and serum lipid levels were measured before and after the web-based nutrition counseling. After nutrition counseling, body mass index significantly decreased in both groups and waist to hip ratio significantly decreased in male hypercholesterolemic patients (p<0.05). Total-cholesterol decreased from 262.2 mg/dL to 234.9 mg/dL, LDL-cholesterol decreased from 186.8 mg/dL to 160.5 mg/dL in hypercholesterolemic patients, triglyceride decreased from 288.6 mg/dL to 211.9 mg/dL and total-cholesterol decreased from 217.2 mg/dL to 198.7 mg/dL in hypertriglyceridemic patients after nutrition counseling. Anthropometric value and nutrient intakes were improved after nutrition counseling. Energy, fat and saturated fatty acid intakes decreased significantly in both groups (p<0.05). Therefore, this study shows that the web-based nutrition counseling is effective in improving food habit and influences positively in serum lipid levels of the patients. In addition, these results indicate that internet presents us with potential as a new medium for nutrition counseling in informationized society.

• The Korean Journal of Quaternary Research
• /
• v.13 no.1
• /
• pp.35-43
• /
• 1999

Goryeri archaeological site is located in the upstream valley of the Danjang River. The basement rocks of the area are composed of the Cretaceous to Palaeogene biotite granite (KbGr), acidic dyke (Kad), Milyang Andesite (Kma) and Jyunggagsan Formation. Among them Milyang Andesite and Jyunggagsan Formation are prevailed in archaeological site and they are composed of reddish brown tuffaceous shale, sandstone and conglomerate, with intercalations of acidic tuffs and lapilli tuffs. The purpose of this research is not only to compare REE pattern of the soil-sedimentary deposits with those of surrounding rocks, but also to identify vitric tephra in the soil-sedimentary deposits derived from the andesite, acidic tuff and lapilii tuff, in order to illucidate the provenance of the vitric tephra. The rare earth element(REE) of the soils and sedimentary deposits results in the same REE pattern with those analyzed from the surrounding basement rocks. This indicates that the soils and sedimentary deposits are originated from the surrounding basement rocks, most probably from the andesite and lapilli tuff. In addition, vitric tephra were identified both in the Quaternary in-situ weathered soils and sedimentary deposits (PMU-13 and PMU-17), and in the weathered surrounding lapilli tuff. These vitric tephra are considered to be different from those of Japanese AT(Aira Tanzawa) -tephra. The latter is predominant with clean, platty, bubble-walled and Y-shaped vitrics, while the former is conspicuous with those shapes of large and diverse size and devitrified, as well as having secondarily bubbled-surfaces reflecting surface weathering. The size of vitric fragments in the Goryeri site is about 300${\mu}{\textrm}{m}$ and large in size in compasion to 150${\mu}{\textrm}{m}$ of Japanese AT-Tephra. The interim results of the research are contradictary to the explanations based on a series of AT-tephra researches carried by Japanese scholar. In short, the vitric materials of the Goryeri archaeological site are most probably originated from the weathering products of the surrounding basement rocks, and are different from the AT-tephra in their size, shape and devitrification properties. Thus it is highly recommended to have a further comprehensive research which is more emphasized the magmatic genesis of these vitric tephra in addition to the external shape and morphology.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.1
• /
• pp.103-113
• /
• 2020

Jack-up drilling rigs are widely used in the offshore oil and gas exploration industry. Although originally designed for use in shallow waters, trends in the energy industry have led to a growing demand for their use in deep sea and harsh environmental conditions. To extend the operating range of jack-up units, their design must be based on reliable analysis while eliminating excessive conservatism. In current industrial practice, jack-up drilling rigs are designed using the working(or allowable) stress design (WSD) method. Recently, classifications have been developed for specific regulations based on the load and resistance factor design (LRFD) method, which emphasises the reliability of the methods. This statistical method utilises the concept of limit state design and uses factored loads and resistance factors to account for uncertainly in the loads and computed strength of the leg components in a jack-up drilling rig. The key differences between the LRFD method and the WSD method must be identified to enable appropriate use of the LRFD method for designing jack-up rigs. Therefore, the aim of this study is to compare and quantitatively investigate the differences between actual jack-up lattice leg structures, which are designed by the WSD and LRFD methods, and subject to different environmental load-to-dead-load ratios, thereby delineating the load-to-capacity ratios of rigs designed using theses methods under these different enviromental conditions. The comparative results are significantly advantageous in the leg design of jack-up rigs, and determine that the jack-up rigs designed using the WSD and LRFD methods with UC values differ by approximately 31 % with respect to the API-RP code basis. It can be observed that the LRFD design method is more advantageous to structure optimization compared to the WSD method.

• The Korean Journal of Air & Space Law and Policy
• /
• v.35 no.3
• /
• pp.127-150
• /
• 2020

A Basic Plan for the Promotion of Space Development (hereinafter referred to as "basic plan"), which prescribes mid- and long-term policy objectives and basic direction-setting on space development every five years, is one of the matters to be deliberated by the National Space Committee. Confirmed February 2018 by the Committee, the 3rd Basic Plan has a unique matter, compared to the 2nd Basic Plan. It is to construct "Korean Positioning System(KPS)". Almost every country in the world including Korea has been relying on GPS. On the occasion of the shooting down of a Korean Air flight 007 by Soviet Russia, GPS Standard Positioning Service has been open to the world. Due to technical errors of GPS or conflict of interests between countries in international relations, however, the above Service can be interrupted at any time. Such cessation might bring extensive damage to the social, economic and security domains of every country. This is why some countries has been constructing an independent global or regional satellite navigation system: EU(Galileo), Russia(Glonass), India(NaVic), Japan(QZSS), and China(Beidou). So does South Korea. Once KPS is built, it is expected to make use of the system in various areas such as transportation, aviation, disaster, construction, defense, ocean, distribution, telecommunication, etc. For this, a pan-governmental governance is needed to be established. And this governance must be based on the law. Korea is richly experienced in developing and operating individually satellite itself, but it has little experience in the simultaneous development and operation of the satellites, ground, and users systems, such as KPS. Therefore we need to review overseas cases, in order to minimize trial and error. U.S. GPS is a classic example.

• Journal of Plant Biotechnology
• /
• v.42 no.3
• /
• pp.161-167
• /
• 2015

Sweetpotato [Ipomoea batatas (L.) Lam] grows well in harsh environmental conditions, and is cultivated as one of the top seven food crops in the world. Recently, sweetpotato is drawing interest from people as a healthy food because it is high in dietary fiber, vitamins, carotenoids and overall nutrition value. However, few studies have been conducted on sweetpotato genome sequencing in spite of its importance. This review is aimed at increasing the efficiency of sweetpotato genome sequencing research as well as establishing a base for gene utilization in order to control useful traits. Recently, animal and plant genome sequencing projects increased significantly. However, sweetpotato genome sequencing has not been performed due to polyploidy and heterogeneity problems in its genome. Meanwhile research on its transcriptome has been conducted actively. Recently, a draft of the diploid sweetpotato genome was reported in 2015 by Japanese researchers. In addition, the Korea-China-Japan Trilateral Research Association of Sweetpotato (TRAS) has conducted research on gene map construction and genome sequencing of the hexaploid sweetpotato Xushu 18 since 2014. The Bill & Melinda Gates Foundation launched the 'sweetpotato genomic sequencing to develop genomic tools for Sub-Sahara Africa breeding program'. The chloroplast genome sequence acquired during sweetpotato genome sequencing is used in evolutionary analyses. In this review, the trend of research in the sweetpotato genome sequencing was analyzed. Research trend analysis like this will provide researchers working toward sweetpotato productivity and nutrient improvement with information on the status of sweetpotato genome research. This will contribute to solving world food, energy and environmental problems.

• Cartoon and Animation Studies
• /
• s.22
• /
• pp.81-97
• /
• 2011

The technology of 'Virtual Reality' has placed in advanced tools for human beings' joy and anger together with sorrow and pleasure in our generation. It has recently tried in a variety ways to use as an implication for treatment in the field of Cognitive Psychology. Especially, it widely approaches to human in terms of that a sense of reality in a virtual world through the five senses should reinterpret the meaning of cognition in the real world. Based on this paradigm shift, it allows for new treatment using the technology of virtual reality. A typical example is a field of Therapy in order to overcome panic disorder. It has advantages that in particular development of flexible interaction technologies in a virtual space can lead patients to experience psychological environments rather than physical one. the interaction technology provides environments in which users' five senses can be actively stimulated, it is very useful that information from the experiences in the virtual world allows people to learn through real experiences by renewing potential energies, advantages of Virtual Reality Therapy can be customized treatment by depending on symptoms in patients with panic disorder and are capable of differentiate application for the cure at each stage. It is to treat by leading patients to get accustomed to environments and situations in real world through care process with each symptom and stage. It is helpful that based on A Human-Sensibility Ergonomics, technologies like immersive virtual reality equipment, force-relative feedback and stereophonic sound, and like stimulating the sense of smell make people to induce experiences by stimulating human's five senses. There are many advantages of immersion in virtual world in that the phenomenon such as challenge, interaction, reality, illusion, and cooperation is expanded. As an application for therapy by growing such augmented reality, virtual space and sharing of data through the Internet and also inexpensive its availability have recently expanded the base. There are other benefits of Virtual Reality Therapy offering active interaction environments for cognitive experience which can provide appropriately adjusted environments for patients who are hard to overcome the real situation because of phobia. In addition to that it is safe and economical and patients' confidentiality is assured. Moreover, due to the principles of applying real-time navigation the Virtual Reality Therapy makes modification and supplementation easier and also it can reduce cybersickness because of the supply of Lenticular allowing people to see stereoscopy without eyeglasses, which makes sense of presence clearer. On top of that due to the development of interactive technologies, it is becoming close to sense of reality similar to real world by leading users to navigate by themselves and to operate objects in a virtual space. This paper will therefore examine, although it is of limited, characteristics of application of virtual reality technology based on A Human-Sensibility Ergonomics used for treatment for a disorder. this paper will analyse a range of its application and problems and it will suggest the future possibilities.