• Geomechanics and Engineering
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• v.27 no.6
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• pp.537-550
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• 2021

There are various technical problems need to be solved in the construction process of pre-setting an isolation wall into a double lane in the outburst prone mine. This study presents a methodology that pre-setting an isolation wall into a double lane without a coal pillar. This requires the excavation of two small section roadways to dig a wide section roadway, followed by construction of the separation wall. During this process the connecting lane is reserved. In order to ensure the stability of the separation wall, the required bearing capacity of the isolation wall is 4.66 MN/m and the deformation of the isolation wall is approximately 25 cm. To reduce the difficulty of implementing support the roadway is driven by 5 m/d. After the construction of the separation wall, the left side coal wall is brushed 1.5 m to make the width of the gas roadway reach 2.5 m and the roadway support utilizes anchor rod, ladder beam, anchor cable beam and net configuration. During construction, the concrete pump and removable self-propelled hydraulic wall mold are used to pump and pour the concrete of the isolation wall. In the process of mining, the stress distribution of coal body and isolation wall is detected and measured on site. The results demonstrate that the deformation of the surrounding rock of roadway and separation of roof in the roadway is small. The stress of the bolt and anchor cable is within equipment tolerance validating their selection. The roadway is well supported and the intended goal is achieved. The methodology can be used for reference for similar mine gas control.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.2
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• pp.277-294
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• 2022

This study was conducted to find a task to adjust the conflict situation by categorizing and analyzing the recent cases of library book censorship and analyzing the field perception on the subject of library book censorship. Therefore, recent cases of book censorship were categorized into four categories: political, legal, sexuality, and sex crime. As a result of the study, 44.5% of the respondents who answered that the restriction on access to books related to sex crimes was not a library censorship or that it was difficult to judge. It showed the perception that this issue is not an issue that can be easily decided by book censorship. Meanwhile, as a result of a survey of librarians, there was an opinion that there was a need for restrictions on collecting or reading at the library site for various reasons, and eventually showed a gap from the code of ethics for librarians against all censorship, showing the need to make efforts to reconcile such conflicts in the future.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.127-140
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• 2022

Recently, accelerators are attracting attention as a new startup incubator. This study empirically analyzed the relative importance and priority of decision-making factors when a startup selects an accelerator using the AHP technique. As a result, startup founders recognized the importance of decision-making factors in the order of funding factors, program factors, and accelerator characteristic factors. there was a difference in the relative importance of detailed factors between startup founders and accelerator workers, depending on the location of the business site and the presence or absence of sales performance. This suggests that accelerators need to strengthen the financial support capabilities and improve customized services to meet the needs of startups. This study can be used as a decision-making criterion when a startup selects an accelerator, and can be used as basic data for additional research on the accelerator program.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.2
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• pp.140-148
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• 2022

Hydrogen is expected to be widely applied in most sectors within the current energy system, such as transportation and logistics, and is expected to be economically and technologically utilized as a power source to achieve vehiclebon emission reduction. In particular, the construction of hydrogen charging station infrastructure will not only support the distribution of hydrogen electric vehicles, but also play an important role in building a hydrogen logistics system. Therefore, This paper suggest additional charging infrastructure areas in Seoul with a focus on supply according to the annual average growth rate (CAGR), centering on Seoul, where hydrogen vehicles are most widely distributed. As of February 2022, hydrogen charging infrastructures were installed in Gangseo-gu, Gangdong-gu, Mapo-gu, Jung-gu, and Seocho-gu in downtown Seoul. Next, looking at the number of hydrogen vehicles by administrative dong in Seoul from 2018 to 2022, Seocho-gu has the most with 246 as of 2022, and Dongjak-gu has the highest average growth rate of 215.4% with a CAGR of 215.4%. Therefore, as a result of CAGR analysis, Dongjak-gu is expected to supply the most hydrogen vehicles in the future, and Seocho-gu currently has the most hydrogen vehicles, so it is likely that additional hydrogen charging infrastructure will be needed between Dongjak-gu and Seocho-gu.

• Journal of Space Technology and Applications
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• v.1 no.3
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• pp.375-395
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• 2021

Korea plans to send a pathfinder lunar orbiter to the Moon for the first time in August 2022. And according to the 3rd Basic Plan for Space Development Promotion, the plan is to send a lunar lander to the Moon before 2030. The selection of the lunar landing area can be varied depending on the lunar lander's mission, therefore preliminary research on the lunar landing sites is essential for a successful lunar exploration mission design. This paper analyzed the characteristics of major regions among 14 proposed regions using NASA's MoonTrek based on the data on the candidate areas for the major moon landing proposed sites by the NASA workshop in 2018. And we looked into what kind of future moon landing missions are suitable for these areas. We also looked at the importance of lunar Antarctica area through the recent lunar landing areas of Moon landing countries and Artemis plan.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.221-243
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• 2023

The use of roadheaders has been increasing to mitigate the problems of noise and vibration during tunneling operations in urban area. Since lack of experience of roadheader for hard rock, the selection of appropriate machines and the evaluation of cutting rates have been challenging. Currently, empirical models developed overseas are commonly used to evaluate cutting rates, but their effectiveness has not been verified for domestic rocks. In this paper, a comprehensive literature review was conducted to assess the rock cutting force, cutterhead capacity, and cutting rate to select the appropriate machine and evaluate its performance. The cutterhead capacity was reviewed based on the literature results for the site. Furthermore, a new empirical model and simplified method for predicting cutting rates were proposed through data analysis in relation to operation time and rock strength, and compared with those of the conventional model from the manufacturer. The results show good agreement for high strength range upper 80 MPa of uniaxial compressive strength.

• Journal of Digital Convergence
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• v.21 no.2
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• pp.1-7
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• 2023

This study examines the policy direction for energy self-reliant islands using marine energy. In other words, it was suggested that the environmental characteristics of the ocean should be considered by conducting a strategic marine environmental impact assessment when establishing an energy-independent island project plan. It was also suggested to proceed with preemptive site selection. In particular, it was emphasized that continuous monitoring of the marine environment should be carried out during the construction and operation of the marine energy development project. In addition, I emphasized the need to seek ways to expand marine environmental impact data and to actively participate and support the residents of the island, which is important in promoting self-reliant islands using ocean energy. This can be said to have a high probability of success when the government-led smart grid project group and KEPCO collaborate with each other. The results of the study analyzed through literature review are as follows. First, active participation and support for initiatives led by residents are needed. second,. KEPCO must collaborate with specialized public institutions such as the Smart Grid Project Group. Third, a strategic marine environment impact assessment should be introduced. Fourth, continuous marine environmental impact investigations should be conducted.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.107-118
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• 2009

As CPT penetration tends to show a similar behavior to that of pile driving, a number of methods for estimating the toe bearing capacity of piles based on CPT data have been proposed. To evaluate the applicability of the methods in this country, a total of 172 dynamic load tests data on PHC piles and 82 CPT data at a site in the Nakdong River estuary were collected. A specific four-step procedure was adopted for the selection of the reliable data, and statistical techniques were then applied to the analysis of the applicability. The results indicated that among a total of 10 CPT-based methods applied, the best one is the Aoki method (1975), followed by the LCPC (1982), ICP (2005) methods and others.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.2
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• pp.83-89
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• 2023

Background: With advances in safety measures for anesthesia, conscious sedation has gained popularity in the field of dentistry and has become essential in dental practice worldwide. However, in Tanzania, intravenous (IV) sedation is rarely practiced in the dental field. Therefore, we report the establishment of sustainable IV conscious sedation in dental practices and subsequently train local OMS residents in Tanzania. Methods: In 2019, intravenous conscious sedation was initiated at the University Dental Clinic of the Muhimbili University of Health and Allied Science (MUHAS), Tanzania. During the preparatory phase of the program, local oral and maxillofacial surgeons (OMSs) were given a series of lecture notes that concentrated on different aspects of IV conscious sedation in dentistry. During the on-site training phase, an oral surgeon from the United States joined the OMSs for case selection, IV-conscious sedation procedures, and patient follow-up. Patients were recruited from existing patient records at the MUHAS Dental Clinic. Results: The first conscious IV sedation program in dentistry was successfully launched at the University Dental Clinic in Tanzania. The local team of OMSs was trained on the safe administration of sedative agents (midazolam or ketamine) to perform various minor surgical procedures in a dental office. Nine patients with different ages, body masses, and medical conditions benefited from the training. No complications were associated with IV conscious sedation in the dental office. Conclusion: This was the first successful "hands-on" training on IV conscious sedation provided to OMSs in Tanzania. It laid the foundation for the sustainable care of patients with special needs requiring oral health-related care in the country.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1439-1447
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• 2023

The fuel cycle characteristics of the IVG.1M reactor were studied within the framework of the research reactor conversion program to modernize the IVG.1M reactor. Optimum use of the nuclear fuel and reactor was achieved through routine methods which included partial fuel reloading combined with scheduled maintenance operations. Since, the additional problem in planning the fuel cycle of the IVG.1M reactor was the poisoning of the beryllium parts of the core, reflector, and control system. An assessment of the residual power and composition of spent fuel is necessary for the selection and justification of the technology for its subsequent management. Computational studies were performed using the MCNP6.1 program and the neutronics model of the IVG.1M reactor. The proposed scheme of annual partial fuel reloading allows for maintaining a high reactor reactivity margin, stabilizing it within 2-4 β_eff for 20 years, and achieving a burnup of 9.9-10.8 MW × day/kg U in the steady state mode of fuel reloading. Spent fuel immediately after unloading from the reactor can be placed in a transport packaging cask for shipping or safely stored in dry storage at the research reactor site.