• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.610-619
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• 2022

Hydrogen is emerging as an alternative fuel for eco-friendly ships because it reacts with oxygen to produce electrical energy and only water as a by-product. However, unlike regular fossil fuels, hydrogen has a material with a high risk of explosion due to its low ignition point and high flammability range. In order to safely use hydrogen in ships, it is an essential task to study the flow characteristics of hydrogen leakage and diffusion need to be studied. In this study, a numerical analysis was performed on the effect of leakage, ventilation, etc. on ventilation performance when hydrogen leaks in an enclosed space such as inside a ship. ANSYS CFX ver 18.1, a commercial CFD software, was used for numerical analysis. The leakage rate was changed to 1 q, 2 q, and 3 q at 1 q = 1 g/s, the ventilation rate was changed to 1 Q, 2 Q and 3 Q at 1 Q = 0.91 m/s, and the ventilation method was changed to type I, type II, type III to analyze the ventilation performance was analyzed. As the amount of leakage increased from 1 q to 3 q, the HMF in the storage room was about 2.4 to 3.0 times higher. Furthermore, the amount of ventilation to reduce the risk of explosion should be at least 2 Q, and it was established that type III was the most suitable method for the formation of negative pressure inside the hydrogen tank storage room.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.320-329
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• 2022

Physiological wear of occlusal surface is inevitable throughout the lifetime, and considered to be normal. Pathologic wear, however, may cause fatal damage to the occlusal surface and destroy esthetics and proper anterior guidance. In such cases, rehabilitation of occlusal wear should be followed by thorough evaluation and diagnosis. In this present case, severe occlusal wear was found in the labial surfaces of mandibular anterior teeth and palatal surfaces of maxillary anterior teeth. Occlusal vertical dimension was evaluated and decided to be regained due to insufficient amount of restorative space. After determining new occlusal vertical dimension, diagnostic wax-up is usually performed to continue prosthodontic treatment. In this case with collapsed occlusion and loss of occlusal vertical dimension, conventional diagnostic wax-up was replaced with various digital devices. Diagnostic wax-up was digitally performed in the software and provisional prosthesis was fabricated with digital tools. With verification with provisional prosthesis, the entire dentition was rehabilitated with newly set occlusal vertical dimension and proper anterior guidance.

• The Korean Journal of Archival Studies
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• no.72
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• pp.165-203
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• 2022

Many people create records in digital space, and the amount of digital records left after individual dies has increased. The digital record left by the deceased is different from the record heritage that has physical substances. In many cases, the records of the deceased not just belong to the deceased, and many deceased did not explicitly disclose their online accounts and method of dispose of digital records during their lifetime, so this problem may lead to problems of inheritance to the bereaved family. In addition, digital records may be neglected or deleted after a person's death due to software problems, specific platform's terms of use, account deletion by bereaved family, etc. This leads to the problem that daily records, which are important clues to the social aspects at the time, are easily lost. Several studies have revealed that individuals are interested in preserving their digital records, but do not know how to do it, so they are benign neglect. For this reason, it is necessary to pay attention to personal digital records and personal digital legacy, and to prepare related policies and plans. Accordingly, this study analyzes problems related to the management of digital records after an individual's death, related to laws and systems, the status and policies of platforms and industries, the status of personal record management, etc. Various solutions were suggested, such as a need for enactment for digital personal record management act, platform's explicit policy for individual's post-mortem records, digital records management plan for archival institutions, individual's a preemptive management plan for his/her own records, and a method for writing a will related to digital account information.

• The Korean Journal of Archival Studies
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• no.71
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• pp.49-89
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• 2022

This study suggests the necessity and domestic application plan a national authority database that promotes an integrated access, richer search, and understanding of historical information sources and archival resources distributed among cultural heritage institutions through the "Social Networks and Archive Context" project case. As the SNAC project was transformed into an international cooperative organization led by NARA, it was possible to secure a sustainable operating system and realize cooperative authority control. In addition, SNAC authority records have the characteristics of providing richer contextual information about life and history and social and intellectual network information compared to libraries. Through case analysis, First, like SNAC, a cooperative body led by the National Archives and having joint ownership of the National Library of Korea should lead the development and expand the scope of participating institutions. Second, in the cooperative method, take a structure in which divisions are made for each field with special strengths, but the main decision-making is made through the administrative team in which the two organizations participate. Third, development of scalable open source software that can collect technical information in various formats when constructing authority data, designing with the structure and elements of archival authority records, designing functions to control the quality of authority records, and building user-friendly interfaces and the need for a platform design reflecting content elements.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.37-43
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• 2022

Patients tend to return to normal pronunciation patterns after fitting new dentures. However, for some patients, it takes a long time to adapt the new complete denture. In this case, the patient came to the hospital at the address of wanting to remake dentures due to wear and tear. After diagnosis through clinical and radiological examination, the maxillary complete denture and mandibular removable partial denture were remade. The patient complained whistling /s/ sound at the first check-up after placement of the new denture. The anterior palatal area of polished surface of the new maxillary complete denture was concave comparing to old denture, and this was the cause of the whistling /s/ sound. A tissue conditioning material was applied to the maxillary complete denture and patient made /s/ sound. The tissue conditioning material was replaced with self-curing type denture base resin, and the patient was immediately satisfied with clear /s/ sound. As an objective assessment, palatogram and speech analytics software was applied. In this case, a patient who received denture treatment complaining of difficulty in pronunciation underwent immediate denture repair, which resulted in patient satisfaction and improved pronunciation through objective evaluation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.117-126
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• 2022

Currently, the number of bridge structures in Korea is continuously increasing and enlarged, and the number of old bridges that have been in service for more than 30 years is also steadily increasing. Bridge aging is being treated as a serious social problem not only in Korea but also around the world, and the existing manpower-centered inspection method is revealing its limitations. Recently, various bridge damage detection studies using deep learning-based image processing algorithms have been conducted, but due to the limitations of the bridge damage data set, most of the bridge damage detection studies are mainly limited to one type of crack, which is also based on a close set classification model. As a detection method, when applied to an actual bridge image, a serious misrecognition problem may occur due to input images of an unknown class such as a background or other objects. In this study, five types of bridge damage including crack were defined and a data set was built, trained as a deep learning model, and an open set recognition-based bridge multiple damage recognition model applied with OpenMax algorithm was constructed. And after performing classification and recognition performance evaluation on the open set including untrained images, the results were analyzed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.503-516
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• 2021

Autonomous fire detection and suppression system requires advanced technology for complex detection technology and injection/control technology for accurate hitting by fire location. Also, foam spraying should be included to respond to oil fires. However, when a single spray monitor is used in common, water and foam spray properties appear different, so for accurate fire suppression, research on the spray trajectory and distance will be required. In this study, experimental studies and numerical analysis studies were combined to analyze the foam spray characteristics through the spray monitor developed for the establishment of an autonomous fire extinguishing system. For flow analysis of foam injection, modeling was performed using OpenFOAM analysis software, and the commonly used foaming agent (Aqueous Film-Forming Foam) was applied for foam properties. The injection distance analysis was performed according to the injection pressure and the injection angle according to the form of the foam, and at the same time, the results were verified and presented through the injection experiment.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.71-82
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• 2022

In order to replace the sampling tensile test of products produced in the tab welding process, which is one of the automotive battery manufacturing processes, vision inspectors are currently being developed and used. However, the vision inspection has the problem of inspection position error and the cost of improving it. In order to solve these problems, there are recent cases of applying deep learning technology. As one such case, this paper tries to examine the usefulness of applying Faster R-CNN, one of the deep learning technologies, to existing product inspection. The images acquired through the existing vision inspection machine are used as training data and trained using the Faster R-CNN ResNet101 V1 1024x1024 model. The results of the conventional vision test and Faster R-CNN test are compared and analyzed based on the test standards of 0% non-detection and 10% over-detection. The non-detection rate is 34.5% in the conventional vision test and 0% in the Faster R-CNN test. The over-detection rate is 100% in the conventional vision test and 6.9% in Faster R-CNN. From these results, it is confirmed that deep learning technology is very useful for detecting welding error of lead tabs in automobile batteries.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.10
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• pp.409-418
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• 2022

In this paper, we propose SAAnnot-C3Pap, a semi-automatic annotation method for obtaining ground truth of a player's posture. In order to obtain ground truth about the two-dimensional joint position in the existing music domain, openpose, a two-dimensional posture estimation method, was used or manually labeled. However, automatic annotation methods such as the existing openpose have the disadvantages of showing inaccurate results even though they are fast. Therefore, this paper proposes SAAnnot-C3Pap, a semi-automated annotation method that is a compromise between the two. The proposed approach consists of three main steps: extracting postures using openpose, correcting the parts with errors among the extracted parts using supervisely, and then analyzing the results of openpose and supervisely. Perform the synchronization process. Through the proposed method, it was possible to correct the incorrect 2D joint position detection result that occurred in the openpose, solve the problem of detecting two or more people, and obtain the ground truth in the playing posture. In the experiment, we compare and analyze the results of the semi-automated annotation method openpose and the SAAnnot-C3Pap proposed in this paper. As a result of comparison, the proposed method showed improvement of posture information incorrectly collected through openpose.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.817-839
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• 2021

To manage software safely, the military acquires and manages products in accordance with the RMF A&A. RMF A&A is standard for acquiring IT products used in the military. And it covers the requirements, acquisition through evaluation and maintenance of products. According to the RMF A&A, product development activities should reflect the risks of the military. In other words, developers have mitigated the risks through security by design and supply chain security. And they submit evidence proving that they have properly comply with RMF A&A's security requirements, and the military will evaluate the evidence to determine whether to acquire IT product. Previously, case study of RMF A&A have been already conducted. But it is difficult to apply in real-world, because it only address part of RMF A&A and detailed information is confidential. In this paper, we propose the evidence fulfilling method that can satisfy the requirements of the RMF A&A. Furthermore, we apply the proposed method to real-world drone system for verifying our method meets the RMF A&A.