• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.113-119
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• 2023

Most infrastructure structures were completed during periods of economic growth. The number of infrastructure structures reaching their lifespan is increasing, and the proportion of old structures is gradually increasing. The functions and performance of these structures at the time of design may deteriorate and may even lead to safety accidents. To prevent this repercussion, accurate inspection and appropriate repair are requisite. To this end, demand is increasing for computer vision and deep learning technology to accurately detect even minute cracks. However, deep learning algorithms require a large number of training data. In particular, label images indicating the location of cracks in the image are required. To secure a large number of those label images, a lot of labor and time are consumed. To reduce these costs as well as increase detection accuracy, this study proposed a learning structure based on mean teacher method. This learning structure was trained on a dataset of 900 labeled image dataset and 3000 unlabeled image dataset. The crack detection network model was evaluated on over 300 labeled image dataset, and the detection accuracy recorded a mean intersection over union of 89.23% and an F1 score of 89.12%. Through this experiment, it was confirmed that detection performance was improved compared to supervised learning. It is expected that this proposed method will be used in the future to reduce the cost required to secure label images.

• Convergence Security Journal
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• v.19 no.3
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• pp.71-79
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• 2019

The demand of smart cars is increasing rapidly. International stand organize such as 3GPP and 5GAA are proposing standard communication protocvols for connected-car, and automotive network infrastructure. But Smart car network have many security threats and more dangerous against the existed wire communication network. Typically, peripheral devices of a smart car may disguise their identity and steal location information and personal information about the vehicle. In addition, the infrastructure elements around smart cars can conspire and put driving cars in danger, threatening lives. This is a very serious security threat. Therefore, in order to solve these problems, we proposed a system that is secure from collusion and tampering attacks using attribute-based authorize delegation method and threshold encryption algorithms. We have demonstrated using a semantic safety model that the proposed system can be safe from collusion attack.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.1-13
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• 2010

This research is the semantic study on the nature cognition and lyricism of pavilion builders as reflected in the pavilion tablets in the Damyang poetry culture area built during 16th century. The names of pavilions, pavilion writings and "poetry with given theme" were studied by actual site visits. The view on the nature and aesthetic awareness of the pavilion builders at the time were explored together with surrounding landscapes. Following conclusions were drawn. 1. Pavilion names borrowed phrases from the famous historical events left by the sages. Or, they took the compliment on the beautiful nature surrounding orthe academic achievement of pavilion owners as the theme, then elaborated them with thinking based on Sung Confucianism. 2. The writings of pavilion literature were the idealistic view on the nature. They think the nature and human as "object and ego are one, object and ego communicate each other, object and ego become one". 3. The nature in the 16th century was the "principle of birth-death-grow-wither" for the intellectuals. They thought that the nature is the ultimate place to return for the realization of life with self-respect. 4. The introduction of fairy land among literary activities in the pavilion was the symbolic means healing the frustrated ego. It was confirmed that they temporarily entrusted their depressed feelings by borrowing the fairy land, far from the reality. The pavilion was the space to escape from the reality and soothe the anger and discord in the reality. 5. The pavilion literature in the Damyang poetry culture area during 16th century sang their pleasure of enjoying the beautiful scenery in the rural area using their social status. The literary works also contained their agony due to the frustration of difficulty in the realization of ideal. When the intellectuals, who already mastered literature, history and philosophy, came down to rural area, built pavilions at the location with beautiful scenery, and spent time while composing poetry, it was an escape from the burden that they should take the social responsibility as the model intellectuals of the society. The pavilions in Damyang poetry-culture area during 16th century were the idealized conceptual world and the space of awareness reflecting the philosophy and thinking of the time.