• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.735-741
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• 2016

Increasing the total length of waveguide-below-cutoff array(WBCA) as it is used to the duct in order to enhance shielding effectiveness, the design could cause higher cost, higher levels of difficulties in construction and the interruption a flow velocity. The multi-layered WBCA can compensate for this problem, which can be designed by crossing each waveguide layer. By conducting simulations from 2-layer to 8-layer structure, it can be observed that the shielding effectiveness increases from 52 dB to 75 dB. Comparing with the original WBCA in a shape of mono layer rectangular, our proposed waveguide becomes similar with the original value as the number of crossing layer increases. In addition, the analysis with the flow of fluid in the duct installed multi-layered WBCA are required. We demonstrate this analysis by doing the flow of fluid simulation, and concluded that the multi-layered WBCA has loss of flow of fluid less than unit rectangular WBCA.

• Maritime Security
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• v.1 no.1
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• pp.93-117
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• 2020

Four cargo ships were ambushed by bombs in 2019 while navigating in the Strait of Hormuz. It was not clear who attacked those ships, however, many nations including the United States argued that it was Iran due to several reasons. The United States established the maritime collective defense system named International Maritime Security Construct (IMSC) in order to protect the maritime security in the Strait of Hormuz, without disclosure against whom it is aimed. Persian, who uses the Persian language unlike other countries in the Middle East, is the major ethnic group in Iran, and most of them believe Shi'ah Islam while most of the Arabs in the Gulf countries adhere to Sunni Islam. It seems that historic and religious motives caused the bipolar system in the Middle East, however, it is plausible to analyze the system of international affairs in the Middle East via defensive or structural realism. Iran has attempted to maintain its hegemony in the region by supporting Shi'ah muslims in the neighboring countries as well as in the world by using military and economic means. In this context, Iran's maritime strategy is to maintain its maritime hegemony on the Persian Gulf via countering threats and cooperating with friendly navies by using the Islamic Republic of Iran Navy(IRIN) and the Islamic Revolutionary Guard Corps Navy(IRGCN). IRIN acts like other navies in the world: protecting national interest at sea, expending its operational areas to the outer seas, and enhancing cooperation with other navies. Meanwhile, IRGCN plays a role as an asymmetric force at sea. It is composed of small and fast asymmetric assets, which can ambush ships fast and furious. Considering the poor study for Iran's maritime strategy in Korea, analyzing the strategy is meaningful for the Republic of Korea Navy, which has operated the Cheonghae Unit for more than ten years since it has extended its operational area over the Strait of Hormuz. In order not to be drawn into the conflict in the Strait, research on the maritime strategy of Iran and other countries in the Middle East should be started.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.67-75
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• 2021

The structure of universities needs to be adjusted and reformed to cope with the decrease in admission resources and the quality of education due to the low birth rate and aging population. Such a policy is receiving much attention. To analyze the relative efficiency of private universities in Korea from the perspective of resource and performance, this study evaluated the efficiency of private university operation by applying a DEA(Data Envelopment Analysis) technique. The DEA measurements were compared with the diagnosis results of the department of education (Government) in 2018. The input and output variables used in the research analysis were utilized by the university's notification materials (public disclosure information). An analysis of the operational efficiency showed that 48% (12 universities) of the 25 DMUs (Decision Making Unit) were efficient for DEA-BCC models and that some of the capacity-building universities were operating efficiently. In addition, the DEA analysis found ways to improve inefficient groups through DEA-Additive results. This paper can be meaningful because it confirmed the relative efficiency of private universities and suggested improvement directions through the DEA method, which is characterized by the simultaneous consideration of various input and output factors. This will help apply the limited resources related to the input and output elements of each university.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.273-278
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• 2013

BACKGROUND: Total petroleum hydrocarbons (TPH), which are main materials of soil contamination by oil, are a term used for any mixture of hydrocarbons. Korea Ministry of Environment established the maximum permissible level of TPH in farmland by 500 mg/kg, and reported that the TPH level of soil in 266 installation such as gas station, transport company, and military unit ranged from 1,356 to 55,117 mg/kg and were much higher than the maximum permissible level in 2011. METHODS AND RESULTS: To determine the effect of TPH on crops, we investigated the effect of gasoline, kerosene, and diesel on the germination and radicle growth of mainly consumed crops. The germination rates of control in investigated all crops ranged from 80.0-100%. The germination and radicle growth in majority of investigated crops were not inhibited even at 2,500 mg/L. However, germination in onion, leek, and green perilla and radicle growth in leek, rape, tomato, and green perilla were significantly inhibited by increasing concentrations of gasoline, kerosene and diesel treatment. Germination and radicle growth inhibition of green perilla by kerosene and diesel were the highest, the percent inhibition at the 500 mg/L were 100 and 98.6%, 100 and 88.2%, respectively. 50% inhibition of germination in green perilla by kerosene and diesel were 39.96 and 29.87 mg/L, and 50% inhibition of radicle growth were 52.76 and 177.96 mg/L, respectively. Conclusion(s): These results suggest the possibility that the maximum permissible level of TPH might to be established general level with exception by crops.

• Journal of the Korean Geographical Society
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• v.38 no.5
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• pp.686-700
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• 2003

In Korea, aside from their official administrative names, aliases of each province or some regions are widely used not only today but also during the Joseon period when the provincial system as local administrative system was firmly implemented. Of aliases, the most representative were Giho, Gwandong, Hoseo, Haeseo, Honam, Yaeongnam, Gwanseo, and Gwanbuk representing the eight provinces (precisely, Gyeonggi and seven provinces) of Chosun Dynasty, as well as Yeongdong and Yeongseo that represent the east and the west of Gangwon-do. These aliases are mostly based on topographical features and physiographical elements, and compared to the official names of eight provinces which depended solely on city names. Of aliases, some appeared in literature during 13-l4th centuries, and all provincial aliases seem to have been widely used after the late 15th century. Aliases continued to be used for 500 to over 700 years. Aliases of eight provinces, geographically, played not lesser role than their official names. Aliases of the eight provinces and regions during the Chosun Dynasty that have been handed down are considered as holding their places' cultural and historical backgrounds, and have become important enough to be accepted as a unit of geographical regional division. The origin and meaning of aliases of each province have been partially disclosed to the geographical circle and the general public. However, the details should be reviewed. First of all, Gwan in Gwanbuk, Gwanseo and Gwandong, as well as Yeong in Yeongnam, Yeongdong and Yeongseo, are each considered as meaning Sobaek Mountain Range and Taebaek Mountain Range with many borderline areas (borders) and military strategic hubs. Also, Ho in Honam, Hoseo, and Giho, are considered as based on the Geum River and Eurimji, and Haeseo are considered as meaning the west of the Gyeonggi Bay, and having relevancy with the first letters of Haeju and Seoha (Pungcheon).

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.515-521
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• 1997

To investigate the nature of the waste materials in the Nanjido Landfill, we have conducted multivariate statistical analysis of geophysical data set comprised of magnetic, gravity, LandSat TM thermal band and surface depression measurement data. Because these data sets show different responses to the depth, we have transformed the observed total field magnetic data and gravity data to the residual reduced-to-pole(RTP) magnetic anomalies and the three dimensional density anomalies, respectively, and utilized the informations about the upper shallow part of the landfills only in the following process. For the statistical analysis at the points of depression measurement, the magnetic, density and LandSat data values at these points are determined by interpolation process. Since the multivarite statistical analysis technique utilizes a clustering algorithm for classification of data set and we have measured the dissimilarity between objects by using Euclidean distance, standardization was applied prior to distance calculation in order to eliminate any scaling effects due to different measurement unit of each data set. The hierarchial grouping technique was used to construct the dendrogram. The optimum number of statistical groups(clusters), which are classified on the basis of geophysical and geotechnical characteristics, appeared to be six on the resulting dendrogram. The result of this study suggests that the dimension and nature of the multicomponent waste landfills can be identified by application of the multivarite statistical analysis technique to integrated geophysical data sets.

• Journal of The Korean Association For Science Education
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• v.44 no.2
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• pp.167-178
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• 2024

In this study, we investigated the perceptions of science-related careers and career education among middle school science teachers. Sixty-four science teachers experienced in teaching unit 7 in the first year of middle school participated. The results of the study revealed that not only careers in science but also careers with science were found to be quite high when teachers were asked to provide examples of science-related careers. Jobs related to research/engineering, which are careers in science, comprised the highest proportion of teachers' answers, followed by jobs related to education/law/social welfare/police/firefighting/military, and health/medical, which are careers with science. However, the proportion of jobs mentioned related to installation/maintenance/production was extremely low. The skills required for science-related careers were mainly perceived to consist of tools for working and ways of working. The number of skills classified under living in the world was perceived to be extremely low across most careers, irrespective of career type. Most teachers only taught unit 7 for two to four sessions and devoted little time to science-related career education, even in general science classes. In the free semester system, a significant number of teachers responded that they provide science-related career education for more than 8 hours. Teachers mainly utilize lecture, discussion/debate, and self-study activities. Meanwhile, in the free semester system, the resource-based learning method was utilized at a high proportion compared to other class situations. Teachers generally made much use of media materials, with the use of textbooks and teacher guides found to be lower than expected. There were also cases of using materials supported by science museums or the Ministry of Education. Teachers preferred to implementing student-centered classes and utilizing various teaching and learning methods. Based on the above research results, discussions were proposed to improve teachers' perceptions of science-related careers and career education.

• Korean Journal of Heritage: History & Science
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• v.48 no.2
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• pp.120-141
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• 2015

This paper is a preliminary study of architectural characteristics of Jangdae (general's podium), which shows one of the technical changes in fortification of Joseon Dynasty. As a facility for commands of generals and training for officers and men, it was located inside a fortress. Although it is not certain when the first Jangdae was built, the number of them dramatically increased around 18th century. Since the top priority function of the Jangdae was the prospect, it was installed at the hilly spot with open architecture. In addition, the open structure of Eupseong fortress towers on the riverside banks could simultaneously offer the functions as viewing around and Jangdae. Since Jangdae was also a place for military drills and reviews of soldiers, a wide podium was positioned at the front to muster the soldiers. This feature was standardized in the space organization of Jangdae in Joseon, and a mere podium was installed unless the topographic restrictions allows enough space. On the other hand, as a place for a commander, the hierarchy of the Jangdae was revealed through a variety of architectural characteristics. The hierarchy was assigned to the commander's space through the altitude difference, and diverse ornaments were added to show a sense of class. The floor plan of the Jangdae building can be largely categorized into rectangle and square, and the typical sizes of the former are $5{\times}4$ Kans (traditional measuring unit between two columns) and $3{\times}2$ Kans. Out of these two types, buildings of $5{\times}4$ Kans were found in flat land and eupseong fortresses with large space, and the relatively smaller ones of $3{\times}2$ Kans in mountain fortresses. All buildings of square floor plan had $3{\times}3$ Kans style, and the center Kan was twice wider than the side Kan to make the central space wide. It seems that the purpose was to secure the interior space of the upper story because the center Kan accounts for the floor area of the upper story. Some Jangdae's had internal story to form overhead space. The multi-roofed tower style with eaves attached to the upper and lower story is found exclusively in Jangdae. The buildings shows the Onkanmulim style which extends Naejinju (inner column) of the lower story to be the Byeonju (outer column) of the upper story, and the log-framed floor in the upper floor was structured by inserting the Changbang (connecting beam) between the Naejinju's and joining the log frames. In addition, the towers in eupseong fortresses had log-framed floor in the upper floor by setting up the high Nuhaju (column underneath a roof) and joining Cheongbang to the upper part of the column while it cannot be regarded as multi-roofed because only the upper part has a roof.

• Korean Journal of Environment and Ecology
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• v.21 no.6
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• pp.515-525
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• 2007

A village grove is the one fostered and protected for a district's traditional community life near the vicinity of a village. This study is done by surveying the vegetation and flora at the village grove situated at the former location for the US military camp. Through such data collected from this study, this researcher could have access to preliminary data needed for restoration project & preservation of not only the village grove surveyed but also the village grove of its neighboring district. According to the survey, there appeared an outgrowth flora of Pteridophyta consisting of 2 families, 2 genuses, 1 species, and 1 variety, totalling to 2 taxa; a Gymnosperm of 2 families, 2 genuses, 3 species, totalling to 3 taxa; in the realm of an Angiosperm, a Monocotyledon consisting of 5 families, 10 genuses, and 11 species, totalling to 11 taxa; Dicotyledoneal consisting of 24 families, 39 genuses, 40 species, and 3 varieties, totalling to 43 taxa, thus revealing 33 families, 53 genuses, 55 species, 4 varieties and 59 taxa in total. Urbanization index(4.2%) and Naturalization ratio(20.3%) showed a relatively higher numerical value than those of other districts. The vegetation unit comprising a village grove is classified Into the four community units, such as Pinus densiflora community, Pinus densiflora-Quercus serrata community, Quercus serrata community, and Rosa multiflora community. Quercus serrata community is of a community type dominated by Quercus serrata, in place of Pinus densiflora selected by natural succession, which shows relatively superior lighting adaptability and was surveyed to grow up on not only a tree layer but also a sub-tree layer. With the recent appearance of industrialization, the use of a village grove is reducing due to villagers' leaving, decrease in the number of households, and urbanization; consequently, there came out a pattern of succession to Quercus serrata community, which could be assumed to be potential natural vegetation of this district, after passing through the process of Pinus densiflora-Quercus serrata community.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.178-199
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• 2011

The ancient tombs found in Bokcheon-dong, Busan originate from the time between the $4^{th}$ and $5^{th}$ centuries, the period of the Three Nations. They are known as the tombs where the Vertical Plate Armour was mainly buried. In 2006, two units of the Vertical Plate Armour were additionally investigated in the tombs No.164 and No.165 which had been constructed at the end of the eastern slope near the hill of the group of ancient tombs in Bokcheon-dong. Throughout this study, the contents of the two units of the Vertical Plate Armour, whose preservation process has been completed, have been arranged, while the group of constructed ancient tombs in Bokcheon-dong from the $4^{th}$ century has been observed through the consideration of the burial pattern. The units of the Vertical Plate Armour from the tombs No.164 and No.165 can be classified as the IIa-typed armor showing the Gyeongju and Ulsan patterns, according to the attribute of the manufacturing technology. Also, they can be chronologically recorded as those from the early period of Stage II among the three stages regarding the chronological recording of the Vertical Plate Armour. While more than two units of the Vertical Plate Armour were buried in the largesized tomb on the top of the hill of the group of ancient tombs, one unit of the Vertical Plate Armour was buried in the small-sized tomb. By considering such a trend, it can be said that in the stage of burying the armor showing the Gyeongju and Ulsan patterns (I-type and IIa-type), different units of the Vertical Plate Armour were buried according to the size of the tomb. However, as the armor showing the Busan pattern (IIb-type) was settled, only one unit was buried. Meanwhile, the tombs No.164 and No.165 can be included in the wooden chamber tomb showing the Gyeongju pattern, which is a slender rectangular wooden chamber tomb with the aspect ratio of more than 1:3. However, according to the trend shown by the buried earthenware, it can be said that there seem to be common types and patterns shared with the earthenware which has been found in the area of Gimhae and is called the one showing the Geumgwan Gaya pattern. In other words, there seem to be close relationships between the subject tombs and the tomb No.3 in Gujeong-dong and the tomb No.55 in Sara-ri, Gyeongju, regarding the types of armor and tombs and the arrangement of buried artifacts. However, the buried earthenware shows a relationship with the areas of Busan and Gimhae. By considering the combined trend of the Gyeongju and Gimhae elements found in one tomb, it is possible to assume that the group of constructed ancient tombs in Bokcheon-dong used to be actively related with both areas. It has been thought that the Vertical Plate Armour used to be the exclusive property of the upper hierarchy until now, since it was buried in the large-sized tomb located on the top of the hill of the group of ancient tombs in Bokcheondong. However, as shown in case of the tombs No.164 and No.165, it has been verified that the Vertical Plate Armour was also buried in the small-sized tomb in terms of such factors as locations, sizes, the amount of buried artifacts and the qualitative aspect. Therefore, it is impossible to discuss the hierarchical characteristic of the tomb just based on the buried units of the Vertical Plate Armour. Also, it is difficult to assume that armor used to symbolize the domination of the military forces. The hierarchical characteristic of the group of constructed ancient tombs in Bokcheon-dong from the $4^{th}$ century can be verified according to the location and size of each tomb. As are sult, the re seem to be some differences regarding the buried units of the vertical plate armour. However, it would be necessary to carry out amore multilateral examination in order to find out whether the burial of the vertical plate armour could be regarded as the artifact which symbolizes the status or class of the deceased.