• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.45-50
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• 1999

The LPG refueling station's explosion at Bucheon city was a major accident which with rare frequency of occurrence and large damage effect. Therefore, to prevent similar accident in the future from LPG charging stations which located in urban area. It needs to identify the damage effects of such facilities by comparing theoretically quantities risk and actual damage. The BLEVE effects from the accident showed similar damage effect in case of heat flux, however, the overpressure level reflected at the reduced distance by $15\%$. The structure damage to the near by area showed comparatively large heat radiation damage to the concrete structure strength and shape changes through heat flux while the overpressure effect was small.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.2
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• pp.81-86
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• 2014

In this paper, we present an effective sound classification system for recognizing the real-time context of a smartphone user. Our system avoids unnecessary consumption of limited computational resource by filtering both silence and white noise out of input sound data in the pre-processing step. It also improves the classification performance on low energy-level sounds by amplifying them as pre-processing. Moreover, for efficient learning and application of HMM classification models, our system executes the dimension reduction and discretization on the feature vectors through k-means clustering. We collected a large amount of 8 different type sound data from daily life in a university research building and then conducted experiments using them. Through these experiments, our system showed high classification performance.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.4
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• pp.40-50
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• 2019

In recent years, it is important to visualize an accurate human body model for the low-end system in the medical imaging field where augmented reality technology and virtual reality technology are used. Decreasing the geometry of a model causes a difference from the original shape and considers the difference as an error. So, the error should be minimized while reducing geometry. In this study, the organ areas of a human body in the tomographic images such as CT or MRI is segmented and 3D geometric model is generated, thereby implementing the reconstruction method of multiple resolution level-of-detail model. In the experiment, a virtual reality platform was constructed to verify the shape of the reconstructed model, targeting the spine area. The 3D human body model and patient information can be verified using the virtual reality platform.

• International Area Studies Review
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• v.15 no.2
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• pp.383-401
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• 2011

This paper studied about environmental protection and Free Trade in FTA. FTA is representative means that maximize trade profit through free trade. But Regulation for environmental protection is infringing profit of free trade(FTA). It is the natural matter that the all countries must do environmental protection. but, measure for environmental protection must not be used on trade limited constituent. This study studied about enactment plan of environmental regulation to achieve two targets of environmental protection with trade liberalization. Study Finding is as following. First, it is that to apply existent environmental standard in the FTA expands trade liberalization. Second, need enactment of rule that can interchange Environmental Goods or a technology effectively. Third, there is necessity to establish procedural regulations and substantial regulations that refer environment problems. also to include comprehensive form in case of choose Multilateral Environmental Agreements is reasonable.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.576-578
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• 2019

VIRTUAL REALITY is a technology that enables users to experience environments that are difficult to experience, such as games, medical care, defense, and manufacturing industries. In this study, we propose the development of contents that can utilize the virtual reality technology to taste the destinations to travel in advance and to select the places to travel. Generally, when you decide on a destination, use the website or booklet to search for information about the destination. In recent years, applications that recommend travel destinations have also been developed and utilized. However, if information about travel destinations is implemented as a virtual reality, it will be possible to obtain more reliable and realistic information. Like Google Maps VR, you can show the globe as a whole, zoom in or out, and click on a keyword to recommend a tourist destination that matches the keyword. It uses internet browsing cookies to automatically display tourist attractions according to user's interest.

• Journal of the Korea Society of Computer and Information
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• v.27 no.3
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• pp.173-182
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• 2022

In this paper, we propose a machine learning model that can prevent fraudulent transactions in advance and interpret them using the XAI approach. For the experiment, we collected a real data set of 12,258 mobile phone sales posts from Joonggonara, a major domestic online C2C resale trading platform. Characteristics of the text corresponding to the post body were extracted using Doc2vec, dimensionality was reduced through PCA, and various derived variables were created based on previous research. To mitigate the data imbalance problem in the preprocessing stage, a complex sampling method that combines oversampling and undersampling was applied. Then, various machine learning models were built to detect fraudulent postings. As a result of the analysis, LightGBM showed the best performance compared to other machine learning models. And as a result of SHAP, if the price is unreasonably low compared to the market price and if there is no indication of the transaction area, there was a high probability that it was a fraudulent post. Also, high price, no safe transaction, the more the courier transaction, and the higher the ratio of 0 in the price also led to fraud.

• Journal of Creative Information Culture
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• v.5 no.3
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• pp.345-353
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• 2019

Several studies have been proposed to improve storage space efficiency by expressing binary trie data structure as a linear binary bit string. Compact binary tree approach generated using one binary trie increases the key search time significantly as the binary bit string becomes very long as the size of the input key set increases. In order to reduce the key search range, a hierarchical compact binary tree technique that hierarchically expresses several small binary compact trees has been proposed. The search time increases proportionally with the number and length of binary bit streams. In this paper, we generate several binary compact trees represented by full binary tries hierarchically. The search performance is improved by allowing a path for the binary bit string corresponding to the search range to be determined through simple numeric conversion. Through the performance evaluation using the worst time and space complexity calculation, the proposed method showed the highest performance for retrieval and key insertion or deletion. In terms of space usage, the proposed method requires about 67% ~ 68% of space compared to the existing methods, showing the best space efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.211-222
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• 2023

Multivariate quadratic equations (MQ)-based public-key cryptographic algorithms are one of promising post-quantumreplacements for currently used public-key cryptography. After selecting to NIST Post-Quantum Cryptography StandardizationRound 3 as one of digital signature finalists, Rainbow was cryptanalyzed by advanced algebraic attacks due to its multiple layered structure. The researches on MQ-based schemes are focusing on UOV with a single layer. In this paper, we propose a new MQ-signature scheme based on UOV using the combinations of the special structure of linear equations, spare polynomials and random polynomials to reduce the secret key size. Our scheme uses the block inversion method using half-sized blockmatrices to improve signing performance. We then provide security analysis, suggest secure parameters at three security levels and investigate their key sizes and signature sizes. Our scheme has the shortest signature length among post-quantumsignature schemes based on other hard problems and its secret key size is reduced by up to 97% compared to UOV.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.265-275
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• 2022

This study analyzes and categorizes the cases of military look's transitional design ideas in recent women's fashion collections, and derives characteristics. The research method is a theoretical review of military look and an analysis of fashion collection cases. The research results were classified into a total of six transformational design ideas. As a structural change in design, it is a decentralized type, a type of expansion and reduction, a change in the entire material, or a transition of some materials, and finally a type according to heterogeneous harmony and organic combination corresponding to styling. Finally, a total of three characteristics are the reconstruction of structural elements, the expansion of the metric of the second mix match, and the emotional fusion of styling. I hope that the study of the transformative type of idea of the new military look will be the driving force for creative design development and will be a basic study that can read the current status and changes of the times throughout fashion design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.655-662
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• 2009

The monitoring for analyzing coastline variations throughout many years is conducted in this study. Haeundae Beach is selected as a test area. We have collected RTK-GPS survey data, airborne LiDAR survey data from Sept. 2008 to 2005. We've done airborne LiDAR survey 2009 to 2006 and we would analyze coastline changes time series through interactive comparison analysis. The mean coastline distance of Haeundae shore is 1,347m (RTK-GPS) by airborne LiDAR survey (2 times). Coastline distance is decreased approximately 4.5% than mean distance in the November survey of 2008. We know right and left sides of the coastline are eroded and the center section shows us the littoral deposit of 3~7m toward sea. It turns out that the sand both sides is transported to the center section by a wave and tide and we know the coastline distance is getting smaller but the coastline width is getting longer like 2~7m.