• 대한공업교육학회지
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• v.31 no.1
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• pp.1-22
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• 2006

The purpose of this study is to measure the level and importance of the key competencies of technical high school students in order to improve their key competencies. The subject was 12 teachers in charge of school-to-work education in a technical high school and 7 managers responsible for an apprentice in a company. The results of this study showed there was a difference in perception of the key competencies between teachers in charge of school-to-work education and managers responsible for that part in a company. Especially, both of two groups, teacher group and manager group, estimated apprentice's comprehension ability of the English documents low and also regarded its importance as low. So the comprehension ability of the English documents needs to be reconsidered as the key competencies. It appeared that the reading comprehension ability of Chinese characters and the ability of listening courteously needed to be added to the existing key competencies. To cultivate them, the key competencies should be examined accurately which technical high school students have to master. And on the basis of this, an instrument to measure the key competencies needs to be developed.

• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.90-95
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• 2011

12-year LIDAR observations of tropospheric aerosol vertical distribution using a Mie scattering LIDAR in Hefei ($31.9^{\circ}N$, $117.2^{\circ}E$) from 1998 to 2009 are presented and analyzed in this paper. Characters of temporal variation and vertical distribution of tropospheric aerosol over Hefei are summarized from the LIDAR measurements. The impacts of natural source and human activities on the aerosol vertical distribution over Hefei could be seen clearly. Dust particles from the north in spring could affect the aerosol distributions below about 12 km over Hefei, and aerosol scale height in April reaches $2.29{\pm}0.68\;km$. Both LIDAR measurements and surface visibility imply that aerosols in the lower troposphere have been increasing since about 2005.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.153-158
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• 2014

A natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer was collected in their sympatric area, the Jucheongang (stream), the Namhangang (river), Korea. Morphological characters as well as mitochondrial cytochrome b (mt-cyb) gene were investigated to confirm the natural hybrid origin. In the comparison of morphological characters, the natural hybrid appeared to have intermediate characters between two parental species in several key characters such as the band of dorsal fins, the color pattern of body, and the body spot and stripe. Also, the collected specimen had an incomplete lateral line with a large number of pored scales. In analysis of mt-cyb gene, it revealed that the maternal species of the natural hybrid appeared to be R. pseudosericeus due to their 100% sequence identity. Thus, such results gave convincing evidence for the occurrence of a natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer.

• Korea Science and Art Forum
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• v.24
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• pp.1-13
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• 2016

The aim of this study is to find the reasons of success and failure of digital animations in terms of 'immersion.' For the purpose, the causes of immersion were analyzed through complex comparison about concepts and stories of two animation films with similar size of budget: 'Shrek 2' which ranked number 1 in the box-office of animation and 'Mars Needs Moms' which ranked number 172 in the same category. The complex results showed that immersion becomes bigger with creativity and popularity of the characters' outer concept, diversity and organic of the characters' inner concept, and diversity and consistency of the background. Moreover, gradual arrangement of characters' appearance in the story and increasing number of the characters, and visual changes around the plot heightening with a well-organized passage increase immersion. After all, immersion of digital animation requires developing creative, diverse, and popular concept and arranging and strengthening strategic well-organized plot of parts and the whole. This is the key to convergence it.

• Smart Structures and Systems
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• v.21 no.5
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• pp.583-590
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• 2018

Nowadays, many tunnels have been commissioned for several decades, which require effective inspection methods to assess their health conditions. The ambient vibration test has been widely adopted for the damage identification of concrete structures. In this study, the vibration characters of tunnel lining shells built with forepoling method was analyzed based on the analytical solutions of the Donnell-Mushtari shell theory. The broken rock, foreploing, rock-concrete contacts between rock mass and concrete lining, was represented by elastic boundaries with normal and shear stiffness. The stiffness of weak contacts has significant effects on the natural frequency of tunnel lining. Numerical simulations were also carried out to compare with the results of the analytical methods, showing that even though the low nature frequency is difficult to distinguish, the presented approach is convenient, effective and accurate to estimate the natural frequency of tunnel linings. Influences of the void, the lining thickness and the concrete type on natural frequencies were evaluated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.846-864
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• 2017

Software Defined Network (SDN) realizes management and control over the underlying forwarding device, along with acquisition and analysis of network topology and flow characters through south bridge protocol. Data path Identification (DPID) is the unique identity for managing the underlying device, so forged DPID can be used to attack the link of underlying forwarding devices, as well as carry out DoS over the upper-level controller. This paper proposes a dynamic defense method based on Client-Puzzle model, in which the controller achieves dynamic management over requests from forwarding devices through generating questions with multi-level difficulty. This method can rapidly reduce network load, and at the same time separate attack flow from legal flow, enabling the controller to provide continuous service for legal visit. We conduct experiments on open-source SDN controllers like Fluid and Ryu, the result of which verifies feasibility of this defense method. The experimental result also shows that when cost of controller and forwarding device increases by about 2%-5%, the cost of attacker's CPU increases by near 90%, which greatly raises the attack difficulty for attackers.

• Korean Journal of Plant Taxonomy
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• v.31 no.4
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• pp.321-341
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• 2001

Phytoliths of leaf blades of Oryza were studied by light and scanning electron microscopy in order to assign the diagnostic character and taxonomic key for the genus. Some phytoliths such as stomatal apparatus, long-cell and short-cell, existing at the same position on the abaxial side of leaf blade, were intensively investigated because of their various forms documented in a previous study. These characters have value either for testing infrageneric classification or for identifying taxa within the genus. Stomatal phytolith is formed by integration of several kinds of sources, such as the guard and subsidiary cell and the papillae. The stomatal phytolith, characterized by not only the absence and presence of phytolith originated by the papillae developed on the guard and subsidiary cell but also their pattern of arrangement, shows various morphologies, and these features have congruent with the infrageneric classification such as section and/or series. Long-cell phytolith is characterized by the absence/presence, arrangement and morphology of phytoliths originated by the papillae on the cell surface. These features may hardly have any systematic relevance within the genus, but contain some informations for identifying of species. All of short-cell phytoliths found are silica body. They form various shapes like cross, bilobate, saddlelike and trilobate, and these features are consistent with infrageneric classification such as section and/or series. Also, some characters, the absence/presence of band of short cell phytolith within costal strip, the absence/presence of saddlelike phytolith within intercostal strip and the number of band of short cell phytolith within costal strip are various according to taxa, but these features do not fall into infrageneric classification. Some taxonomic keys on the phytoliths of stomatal, long-cell and short-cell were developed by their features, and the agreement between these characters and infrageneric classifications was also discussed.

• Korean Journal of Plant Taxonomy
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• v.44 no.4
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• pp.261-275
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• 2014

Although a few recent taxonomic studies focusing on infraspecific taxa in each species of Isodon have been reported, a detailed taxonomic revision of the Korean Isodon taxa has yet to be performed. We investigated the morphological characters of Korean Isodon based on approximately 600 herbarium sheets from major herbaria in Korea and Japan. We identified characters which distinguish seven Korean Isodon taxa and created a key to Korean Isodon based on the results from this study and on recent studies of the Korean Isodon taxa. The following unique characters for several taxa were recognized: 1) dense non-glandular hairs in stems for I. inflexus var. canescens (over 70 ea/mm on one side of the stem), 2) dense glandular hairs on the abaxial surface of the leaf for I. serra (over $40ea/mm^2$), 3) protruding pistils and stamens from the corolla with the length of the protruding part longer than that of the lower lobe of corolla for I. japonicus, and 4) the presence of non-glandular hairs on the entire surface of the fruit of I. inflexus var. microphyllus. Based on this study, we recognized that there are four species, two varieties, and one forma of Isodon taxa in Korea.

• Animal Systematics, Evolution and Diversity
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• v.23 no.1
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• pp.87-89
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• 2007

The larval stage of Copera tokyoensis Asahina is described for the first time from Korea. The larva can be distinguished from other known larvae of Copera by the absence of lateral setae on the abdominal segments and by the labial palpal lobe, which bears three setae. Line-drawings of key characters and discussion on Korean Copera are provided.

• Animal Systematics, Evolution and Diversity
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• v.23 no.1
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• pp.21-33
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• 2007

A taxonomic study of the genus Oxytelus Gravenhorst in Korea is presented. Seven species are recognized, three of which are identified for the first time in Korea (O. incisus Motschulsky, O. migrator Fauvel, and O. takahashii Ito). A key and diagnostic characters with illustrations are provided.