• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.980-991
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• 2023

To prevent accidents near the quay caused by a ship, ports are generally designed and constructed through navigation and berthing safety assessment. However, unpredictable accidents such as ship collisions with the quay or personal accidents caused by ropes still occur sometimes during the ship berthing or mooring process. Automatic mooring systems, which are equipped with an attachment mechanism composed of robotic manipulators and vacuum pads, are designed for rapid and safe mooring of ships. This paper deals with a displacement and velocity measurement system for the automatic mooring device, which is essential for the position and speed control of the vacuum pads. To design a suitable system for an automatic mooring device, we first analyze the sensor's performance and outdoor environmental characteristics. Based on the analysis results, we describe the configuration and design methods of a displacement and velocity measurement system for application in outdoor environments. Additionally, several algorithms for detecting the sensor's state and estimating a ship's velocity are developed. The proposed method is verified through some experiments for displacement and speed measurement targeted at a moving object with constant speed.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.6
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• pp.46-60
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• 2023

This study examines the appropriateness of indicators and methodologies through the evaluation of cultural services in border areas and uses them as basic data for the ecosystem service-based management of border areas, which are key domestic ecological assets. Accordingly, in this study, seven border cities and counties were evaluated and compared based on the evaluation indicators and methods presented by the National Institute of Ecology. As a result of the cultural service evaluation, it was found that Paju City was superior in leisure and tourism, Inje-gun was best in scenic beauty and heritage, and Yanggu-gun was strongest in education, and Inje-gun in heritage. Accordingly, through this study, future tasks for comprehensive cultural service evaluation were presented as follows. First, in order to evaluate ecosystem services at the national and regional levels, it is necessary to establish an indicator system for cultural service evaluation and monitoring. Second, when building a cultural service evaluation index system, it is necessary to review upper and lower conceptual units and the consistency between indicators according to the scale of the evaluation region. Third, a specific review of DB utilization for cultural service evaluation should be conducted depending on the type of ecosystem. Lastly, given the significant lack of domestic cultural service research, additional basic research must be conducted to evaluate cultural services including non-material and qualitative perceptions. In order to evaluate cultural services in the future, additional basic research is needed for each ecosystem type, and a process of finding appropriate evaluation indicators and methods through research is necessary.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.115-125
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• 2023

In this study, we evaluated the behavior of frozen soil using an electrical resistivity survey method-a nondestructive technique-and examined its characteristics through field experiments. Frozen soil was artificially prepared by injecting fluid to accelerate the freezing process, and naturally frozen soil was selected in a nearby area for comparison. A dynamic cone penetration test (DCPT) was performed to compare the reliability of the electrical resistivity survey, and time-domain reflectometry surveys were performed to assess the moisture content of the ground. Field experiments were conducted in February-when the atmosphere temperature was below freezing-and May-when the temperature was above freezing. This temperature-compensated method was used to determine reliability because the behavior of frozen soil depends on the underlying temperature. In the resistivity survey method, a section of high electrical resistivity was observed under freezing conditions due to the frozen water and converted into porosity. The converted porosity was compared with the porosity inferred from the DCPT, and the results showed that the measured electrical resistivity was valid.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.27-35
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• 2024

Fuel gases such as methane and propane are used in explosion hazardous area of domestic plants and can form non-uniform mixtures with the influence of process conditions due to leakage. The fire-explosion risk assessment using literature data measured under uniform mixtures, damage prediction can be obtained the different results from actual explosion accidents by gas leaks. An explosion characteristics such as explosion pressure and flame velocity of non-uniform gas mixtures with concentration change similar to that of facility leak were examined. The experiments were conducted in a closed 0.82 m long stainless steel duct with observation recorded by color high speed camera and piezo pressure sensor. Also we proposed the quantification method of non-uniform mixtures from a regression analysis model on the change of concentration difference with time in explosion duct. For the non-uniform condition of this study, the area of flame surface enlarged with increasing the concentration non-uniform in the flame propagation of methane and was similar to the wrinkled flame structure existing in a turbulent flame. The time to peak pressure of methane decreased as the non-uniform increased and the explosion pressure increased with increasing the non-uniform. The ranges of K_G (Deflagration index) of methane with the concentration non-uniform were 1.30 to 1.58 [MPa·m/s] and the increase rate of K_G was 17.7% in methane with changing from uniform to non-uniform.

• Information Systems Review
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• v.22 no.4
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• pp.185-203
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• 2020

With the advent of 4th industrial revolution, the manufacturing industry is converging with ICT and changing into the era of smart manufacturing. In the smart factory, all machines and facilities are connected based on ICT, and thus security should be further strengthened as it is exposed to complex security threats that were not previously recognized. To reduce the risk of security incidents and successfully implement smart factories, it is necessary to identify key security factors to be applied, taking into account the characteristics of the industrial environment of smart factories utilizing ICT. In this study, we propose a 'hierarchical classification model of security factors in smart factory' that includes terminal, network, platform/service categories and analyze the importance of security factors to be applied when developing smart factories. We conducted an assessment of importance of security factors to the groups of smart factories and security experts. In this study, the relative importance of security factors of smart factory was derived by using AHP technique, and the priority among the security factors is presented. Based on the results of this research, it contributes to building the smart factory more securely and establishing information security required in the era of smart manufacturing.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.473-485
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• 2022

The incidence of neurodegenerative diseases in the older population has increased in recent years. A considerable number of studies have been performed to characterize these diseases. Imaging analysis is an important biomarker for the diagnosis of neurodegenerative disease. Objective and reliable assessment and precise detection are important for the early diagnosis of neurodegenerative diseases. Artificial intelligence (AI) using brain MRI applied to the study of neurodegenerative diseases could promote early diagnosis and optimal decisions for treatment plans. MRI-based AI software have been developed and studied worldwide. Representatively, there are MRI-based volumetry and segmentation software. In this review, we present the development process of brain volumetry analysis software in neurodegenerative diseases, currently used and developed AI software for neurodegenerative disease in the Republic of Korea, probable uses of AI in the future, and AI software limitations.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.25-35
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• 2023

Background: In order to emphasize the importance of clinical dental hygienists-led dental hygiene management processes for those with systemic diseases, we tried to identify systemic diseases affecting dental implants based on clinical data. Methods: In order to identify systemic diseases affecting dental implants, literature review was conducted from March 1 to May 31, 2023, and the search period was for research papers published in domestic and foreign academic journals from January 2000 to December 2020. Domestic databases used for search use RISS, Nuri Media(DBpia), and Korea Academic Information (http://www.papersearch.net ; KISS), while overseas databases searched Pubmed for dental implant failures, implants, systemic diseases, and Dental implant and system disease. Results: The cumulative survival rate of implants averaged 94.3 percent and the failure rate was 5.7 percent. Clinical analysis of systemic diseases related to implants accounted for the highest frequency with 13 (100.0%), followed by 8 (61.5%) studies on high blood pressure and smoking, 7 (53.8%) cardiovascular diseases, and 5 (38.5%). In addition, liver disease, thyroid abnormalities, blood abnormalities, organ transplants and infectious diseases were confirmed. Conclusion: Since unregulated systemic diseases are a risk factor for implant failure, clinical dental hygienists should continue to maintain healthy oral conditions by sharing information with patients during periodic preventive dental hygiene management processes such as dental hygiene assessment.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.599-614
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• 2024

To evaluate the safety status of deteriorated segments in a submarine shield tunnel during its service life, a seepage model was established based on a cross-sea shield tunnel project. This model was used to study the migration patterns of erosive ions within the shield segments. Based on these laws, the degree of deterioration of the segments was determined. Using the derived analytical solution, the internal forces within the segments were calculated. Lastly, by applying the formula for calculating safety factors, the variation trends in the safety factors of segments with different degrees of deterioration were obtained. The findings demonstrate that corrosive seawater presents the evolution characteristics of continuous seepage from the outside to the inside of the tunnel. The nearby seepage field shows locally concentrated characteristics when there is leakage at the joint, which causes the seepage field's depth and scope to significantly increase. The chlorine ion content decreases gradually with the increase of the distance from the outer surface of the tunnel. The penetration of erosion ions in the segment is facilitated by the presence of water pressure. The ion content of the entire ring segment lining structure is related in the following order: vault < haunch < springing. The difference in the segment's rate of increase in chlorine ion content decreases as service time increases. Based on the analytical solution calculation, the segment's safety factor drops more when the joint leaks than when its intact, and the change rate between the two states exhibits a general downward trend. The safety factor shows a similar change rule at different water depths and continuously decreases at the same segment position as the water depth increases. The three phases of "sudden drop-rise-stability" are represented by a "spoon-shaped" change rule on the safety factor's change curve. The issue of the poor applicability of indicators in earlier studies is resolved by the analytical solution, which only requires determining the loss degree of the segment lining's effective bearing thickness to calculate the safety factor of any cross-section of the shield tunnel. The analytical solution's computation results, however, have some safety margins and are cautious. The process of establishing the evaluation model indicates that the secondary lining made of molded concrete can also have its safety status assessed using the analytical solution. It is very important for the safe operation of the tunnel and the safety of people's property and has a wide range of applications.

• The Korean Journal of Archival Studies
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• no.79
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• pp.471-513
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• 2024

The monthly news and culture magazine, 'Sasanggye,' established by Jang Jun-ha from 1953 to 1970, served as a platform for government criticism and intellectual representation. The magazine created photographic-essays covering a variety of topics and utilized images as a visually impactful tool with news value. This paper aims to critically examine the photographic-essays within 'Sasanggye' as archival records, shedding light on their intrinsic value. Before delving into this assessment, the paper thoroughly explores the developmental process and characteristics of these photographic-essays. And based on the content divisions within the main text, the paper categorized the themes captured in the photographic essays into politics, economics, society, culture, and miscellaneous topics. It then introduced representative photographicessays. From an archival perspective, looking at photographs involves elucidating that photographs carry meanings beyond mere data. The photographic essays in 'Sasanggye' serve as photographic records providing evidence of 1960s Korean society and encapsulating crucial visual information. Furthermore, the photographic essays in 'Sasanggye' hold a historical significance in the aspect of Korean magazine documentary photography. The photo-essays in 'Sasanggye' carry worth in the history of photography and encompass evidential and informational values as photographic records.

• Tunnel and Underground Space
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• v.34 no.2
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• pp.89-103
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• 2024

In the disposal environment, gases can be generated at the interface between canister and buffer due to various factors such as anaerobic corrosion, radiolysis, and microbial degradation. If the gas generation rate exceeds the diffusion rate, the gas within the buffer may compress, resulting in physical damage to the buffer due to the increased pore pressure. In particular, the rapid movement of gases, known as gas breakthroughs, through the dilatancy pathway formed during this process may lead to releasing radionuclide. Therefore, understanding these gas generation and movement mechanism is essential for the safety assessment of the disposal systems. In this study, an experimental apparatus for investigating gas migration within buffer was constructed based on a literature review. Subsequently, a gas injection experiment was conducted on a compacted bentonite block made of Bentonile WRK (Clariant Ltd.) powder. The results clearly demonstrated a sharp increase in stress and pressure typically observed at the onset of gas breakthrough within the buffer. Additionally, the range of stresses induced by the swelling phenomenon of the buffer, was 4.7 to 9.1 MPa. The apparent gas entry pressure was determined to be approximately 7.8 MPa. The equipment established in this study is expected to be utilized for various experiments aimed at building a database on the initial properties of buffer and the conditions during gas injection, contributing to understanding the gas migration phenomena.