• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.471-472
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• 2016

• Water for future
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• v.55 no.6
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• pp.72-81
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• 2022

• Korean Journal of Environment and Ecology
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• v.21 no.6
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• pp.468-486
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• 2007

It was found that vascular plants distributed at Yeondo islet were composed of 107 families, 312 genera, 408 species, 2 subspecies, 51 varieties and 5 forms, totaling 466 taxa. 39 species including Myrica rubra among the 466 taxa were evergreen broad-leaved tree, and as for flora region science-based specially designated plants by the Ministry of Environment, it was surveyed that 85 taxa(46 families, 70 genera, 80 species and 5 varieties) were distributed by identifying 53 taxa in grade one, 1 taxa in grade two, 26 taxa in grade three, 3 taxa in grade four, and Milletia japonica and Arisaema negishii in grade five. In the naturalized plants, a total of 42 taxa(13 families, 37 genera, 40 species and 2 varieties) were surveyed to be distributed and the ratio of their naturalization and Urbanization Index was analyzed to be 9.01% and 14.63%, respectively. Life form spectra bore a type of H-Dl-R5-e. Vegetation of Yeondo islet are classified as Pinus thunbergii community and Castanopsis sieboldii community, and Miscanthus sinesis var. purpurascens community spread on an gently slanted mountain side.

• Korean Journal of Environment and Ecology
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• v.9 no.2
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• pp.77-98
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• 1996

The flora of the Odaesan National Park, located in the areas of Pyongchang-gun, Myongju-gun and Inje-gun, Kangwon-do was surveyed. Field works was undertaken five times between March to October, 1995. The total number of vascular plants in the Odaesan National Park was surveyed was 512 taxa; 87 families, 277 genera, 435 species, 68 varieties, 2 subspecies, and 7 forms. The vascular plants were classified as 459 taxa, 85 families, 255 genera, 389 species, 61 varieties, 2 subspecies and 7 forms in Odaesan, 309 taxa 73 families, 194 genera, 257 species, 45varieties, and 5 forms in Hwangbyongsan and 151 taxa, 60 families, 115 genera, 138 species, 12 varieties and 1 form in Sogumgang area. Also this study recorded 35 taxa of Korean rare and endangered plant species. Some of the habitats of rare and endangered plant species are located in the vicinity from the nature trails. Conservation measures, at both the habitat and species levels, are urgently needed to mitigate against destructive human activities, such as an illegal mass collecting and trampling.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.50-62
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• 2007

The flora of Banwol, Donghwa and Samhwa stream of the Sihwaho Phragmites communis wetland park was listed as 242 taxa; 72 families, 175 genera, 201 species, 38 varieties, 2 forms and 1 cultivar. Among these taxa, there were 92 taxa (38.0%) for the planted species, while 150 taxa (62.0%) for the native species. The halophytes were summarized as 13 taxa (5.4% among total 242 taxa); 5 families, 9 genera, 12 species, 1 variety. The naturalized plants were composed of 17 families, 41 genera, 45 species, 1 variety, totaling 46 taxa and naturalization index, urbanization index were 19.0%, 17.0%, respectively.

• Korean Journal of Plant Taxonomy
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• v.32 no.4
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• pp.397-416
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• 2002

A taxonomic study of Viola section Chamaemelanium in Korea, based on morphological characters, was conducted with light microscopy and scanning electron microscopy. Two species, V. orientalis W. Becker and V. brevistipulata (Fr. et Sav.) W. Becker, are recognized by rhizome and cauline habits, trichomes on the ovary and the shape and beards of stigmas. The latter can be split further into three varieties, var. brevistipulata, var. minor Nakai and var. laciniata (Boiss.) W. Becker, according to the leaf morphology in particular. Viola brevistipulata var. laciniata has the most tooth number, and its teeth are irregular erose but the other two varieties are regular sinuate or serrate. As for the size of leaves, V. brevistipular var. brevistipulata is the largest but V. brevistipulata var. minor is the smallest among the varities. Of them, V. brevistipulata var. laciniata is newly recorded in Korea. It was also revealed that both development and arrangement of the beards developed on the ovary and stigma were particularly diagnostic in the identification of the Viola section Chamaemelanium species.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.10-17
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• 2015

A satellite communication system is one of viable solutions for Internet applications running in wide areas. However, the performance of TCP can be seriously degraded in the satellite networks due to long round-trip time (RTT) and high bit error rate (BER) over satellite links. Therefore, a performance enhancing proxy(PEP) based TCP splitting connection scheme is used in the satellite link to improve the TCP performance. In this paper, we implement PEP testbed and conduct experiment to evaluate the performance of TCP splitting connection by comparing with high-speed TCP solutions in various environments. In our experimental environment, we consider multiple connections, high packet loss, and limited bandwidth. The experiment results show that PEP improves the TCP throughput than high-speed TCP variants in various environments. However, there is no improvement of the TCP throughput with the limited bandwidth because there is packet loss caused by both the congestion and the channel error.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.3
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• pp.17-28
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• 2006

The appearance of variant malicious codes using obfuscation techniques is accelerating the spread of malicious codes around the detection by a vaccine. n a system does not patch detection patterns for vulnerabilities and worms to the vaccine, it can be infected by the worms and malicious codes can be spreaded rapidly to other systems and networks in a few minute. Moreover, It is limited to the conventional pattern based detection and treatment for variants or new malicious codes. In this paper, we propose a method of behavior based detection by the static analysis, the dynamic analysis and the dynamic monitoring to detect a malicious code using obfuscation techniques with the PE compression. Also we show that dynamic monitoring can detect worms with the PE compression which accesses to important resources such as a registry, a cpu, a memory and files with the proposed method for similarity.

• Journal of Internet Computing and Services
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• v.22 no.3
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• pp.45-52
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• 2021

Although many studies have been conducted to identify unknown attacks in cyber security intrusion detection systems, studies based on outliers are attracting attention. Accordingly, we identify outliers by defining categories for unknown attacks. The unknown attacks were investigated in two categories: first, there are factors that generate variant attacks, and second, studies that classify them into new types. We have conducted outlier studies that can identify similar data, such as variants, in the category of studies that generate variant attacks. The big problem of identifying anomalies in the intrusion detection system is that normal and aggressive behavior share the same space. For this, we applied a technique that can be divided into clear types for normal and attack by discrete wavelet transformation and detected anomalies. As a result, we confirmed that the outliers can be identified through One-Class SVM in the data reconstructed by discrete wavelet transform.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.997-1008
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• 2022

Today, AI(Artificial Intelligence) technology is being extensively researched in various fields, including the field of malware detection. To introduce AI systems into roles that protect important decisions and resources, it must be a reliable AI model. AI model that dependent on training dataset should be verified to be robust against new attacks. Rather than generating new malware detection, attackers find malware detection that succeed in attacking by mass-producing strains of previously detected malware detection. Most of the attacks, such as adversarial attacks, that lead to misclassification of AI models, are made by slightly modifying past attacks. Robust models that can be defended against these variants is needed, and the Robustness level of the model cannot be evaluated with accuracy and recall, which are widely used as AI evaluation indicators. In this paper, we experiment a framework to evaluate robustness level by generating an adversarial sample based on one of the adversarial attacks, C&W attack, and to improve robustness level through adversarial training. Through experiments based on malware dataset in this study, the limitations and possibilities of the proposed method in the field of malware detection were confirmed.