• Korean Journal of Plant Taxonomy
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• v.47 no.3
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• pp.180-188
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• 2017

We evaluated the actual distribution, present status, and number of remnant individuals of Korean Sagittaria aginashi (Alismataceae) based on herbarium specimens and field surveys. We also reidentified Korean S. aginashi by analyzing sequences of the internal transcribed spacer (ITS) region. We found nine specimens of S. aginashi in herbaria from four localities housed at the Osaka Museum of Natural History (OSA) and at the Korea National Herbarium (KH). During our field research, we could not confirm the current statuses of two collection localities (Taereung and Ansan-si), though this was not the case for Ulsan-si. In addition, we found two new localities in Ulsan-si and Yangsan-si. These three remnant populations are distributed in wetlands in mountainous areas (elev. 480-740 m). With regard to the number of flowering and immature individuals in the three localities, there were <50 and <2,000, respectively, in total. ITS sequences demonstrated that the sequences of Korean and Japanese S. aginashi are uniform and distinct from other Sagittaria species. These results indicate that S. aginashi is a rare and threatened species in Korea. It should be listed as an endangered species on the Korean Red List and requires urgent protection by conservation programs, including the extensive surveys of other possible natural habitats.

• Journal for History of Mathematics
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• v.21 no.4
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• pp.79-86
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• 2008

The sex ratio at birth of South Korea is exceeding the natural sex ratio at birth, which is estimated to be about 105. One of the reasons of high sex ratio at birth is due to sex-selective abortion which is caused by strong son preference. The main objective of this study is to identify whether the families which are trying to bear children only until they acquire one son contribute to high sex ratio at birth. As a result, we obtain the theorem that if the number of such families diverge, the sex ratio at birth converges to the natural sex ratio almost surely. Therefore, we conclude that the existence of the families which are trying to bear children only until they receive one son does not affect the sex ratio at birth.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.47-58
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• 2020

This study was done to evaluate resources distributed around the Nakdong-Jeongmaek which is the eastern ridge line of the Nakdong-river basin with 437km in length. Here we found and/or searched for thousands of resources within each of 210 villages around the ridge, which were divided into six categories including landscape, natural park, protected area, history, tourism and biodiversity. An inventory was also created using an attribute table in a shape file for identifying the spatial location and property for every resource existing in each village. Each of fields for six-typed resources has 210 records representing each village and resources within it. If a resource exists in a village, '1' is assigned for its existence in its corresponding record. Otherwise, '0' is assigned for its non-existence in the record. The number of '1' on six records for a village is meaning the number of resources contained within a village, which can be a barometer to decide the properties of each village. In this study, we found five core villages containing all kind of resources in it, while 52 villages were found having only a single type of resources within it. The other villages were known to have multiple resources like having two or more ones.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.63-68
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• 2003

We investigated the sequence divergence of the geographic samples of the queen bumble bee (Bombus ardens) in Korea. A portion of mitochondrial COI gene sequences (423 bp) was analyzed for 44 individuals collected from seven localities. Sequence analysis resulted in four COI haplotypes with the maximum nucleotide divergence of only 0.5% (two bp). One haplotype (BA1) was dominant in all localities surveyed (86.4%). The finding of low sequence divergence and dominance of one haplotype appear to reflect, although limited, the life history of the B. ardens queens subjected to active dispersal and seasonal fluctuation in queen number.

• Journal of Environmental Impact Assessment
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• v.4 no.1
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• pp.65-78
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• 1995

The resident attitude for preservation and development of amenity in Eulsuk island and its downstream area at estuary of Nakdong river in Korea were investigated by the questionnaires and the field surveys. Based on the results, the characteristics of this study area are the natural ecological preservation area, natural environmental preservation area and curtural assets for migratory birds. And there are a estuary bank, a Dadae beach and a Molundae park. Special amenities are (1) the light (sunrise, sunset etc), (2) the water(river, sea etc.), (3) the air(fresh wind, beautiful sound etc.), (4) the land space(beautiful view, recreation field, reed area, pine forest etc.) and (5) the stream(dancing of migratory birds, water flow, folk dance, history remains etc.). But at present, the environmental qualities as health, aesthetics safety, amenity and culture are deteriorated by development. So the number of migratory birds are decreasing. The residents desired that in future this area be use for the recreation space, the park and the natural leaning fields etc, as well as the restoration of destroyed resources.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.581-597
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• 2017

In this study, we conducted a statistical analysis to see how visitors were satisfied through experiences at the Goseong Dinosaur Museum, which is a representative natural history museum in the Republic of Korea. As a result, during the last 10 years (2005-2014) the total number of visitors to the Goseong Dinosaur Museum was more than 3,410,000 persons. The maximum- and minimum number of visitors per year was more than 440,000 and 300,000 persons, respectively. The annual average number was more than ca. 340,000 persons. Among the visitors, the number of individual visitors was more than 2,800,000 persons (82.0%) and the number of group visitors was about 610,000 persons (18.0%). As a result of the monthly visitor analysis, the maximum number of visitors was about 530,000 persons in August while the minimum number of visitors was about 140,000 persons in February. The visiting patterns of the individual and group visitors were different. There were the largest number of the individual visitors in August and the smallest number of them in December, whereas the largest number of the group visitors in October and the smallest number of them in February. The visitor's residence was generally proportional to the geographical accessibility and the number of people in their residence. The results showed that the degree of visitor's satisfaction using Likert scale was relatively high with the score of 4.1. However, the visitors recommended that some facilities should be improved. Regarding the number of visits and the intention of revisit, 102 persons (53.1%) of 192 made a visit to the museum more than two times, and 178 persons (89.9%) of 198 visitors would like to visit the museum again. It is recommended that the results of this study be used in developing a long term-plan or for the Goseong Dinosaur Museum.

• Journal of architectural history
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• v.14 no.4 s.44
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• pp.73-86
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• 2005

The purpose of this study is to prove the correlations among various factors what determined to formation of front elevation proportion system through making an actual survey and investigating. According to the analysis of them, we make conclusions as follows; 1, On the assumption that average distance of 1Kan(間) is 1, the height of foundation is 0.21, the height of floor from foundation is 0.24, the height of normal column from floor is 0.85, the height of eaves from foundation is 1.10. 2. Southeast faced buildings are wider than southwest faced buildings in the distance of 1Kan (間) in the range of $110{sim}220mm$. The height of foundation and floor in the southeast faced buildings are higher than those in southwest faced buildings beside the height of normal column, eaves, high column in the southwest faced buildings are higher than those in southeast faced buildings. 3. As number of front Kan(間) increases, the distance of 1Kan(間) decrease and the height of eaves and high column(高柱) increases. This is cause of making a maximum needed inner space by increasing the distance of 1Kan(間). This is an wisdom for living from ancestors. 4. As number of Dori(道里) increases, the distances of 1Kan are nearly same but the height of eaves and high column(高柱) increases about 300mm, This is a natural result from an increasing of building scale. 5. The distance of 1Kan(間) in later 19C building is most wide but, the unit heights are minimal average values at year 1900 as a reference mark. After this, the height of normal column, eaves, high column are higher about $170{sim}330mm$. 6. The number of Kan in front elevation, Dori(道里), and direction of building have correlations each other in proportion system of traditional housing An-Chae with significant level, p<0.05.

• Journal for History of Mathematics
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• v.24 no.4
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• pp.1-6
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• 2011

We investigate a method to find the least common multiples of numbers in the mathematics book GuIlJib(구일집(九一集), 1724) written by the greatest mathematician Hong Jung Ha(홍정하(洪正夏), 1684~?) in Chosun dynasty and then show his achievement on Number Theory. He first noticed that for the greatest common divisor d and the least common multiple l of two natural numbers a, b, l = $a\frac{b}{d}$ = $b\frac{a}{d}$ and $\frac{a}{d}$, $\frac{b}{d}$ are relatively prime and then obtained that for natural numbers $a_1,\;a_2,{\ldots},a_n$, their greatest common divisor D and least common multiple L, $\frac{ai}{D}$($1{\leq}i{\leq}n$) are relatively prime and there are relatively prime numbers $c_i(1{\leq}i{\leq}n)$ with L = $a_ic_i(1{\leq}i{\leq}n)$. The result is one of the most prominent mathematical results Number Theory in Chosun dynasty. The purpose of this paper is to show a process for Hong Jung Ha to capture and reveal a mathematical structure in the theory.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.227-245
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• 2013

Reliable strength assessment of the Liquefied Natural Gas (LNG) cargo containment system under the sloshing impact load is very difficult task due to the complexity of the physics involved in, both in terms of the hydrodynamics and structural mechanics. Out of all those complexities, the proper selection of the design sloshing load which is applied to the structural model of the LNG cargo containment system, is one of the most challenging one due to its inherent randomness as well as the statistical analysis which is tightly linked to the design sloshing load selection. In this study, the response based strength assessment procedure of LNG cargo containment system has been developed and proposed as an alternative design methodology. Sloshing pressure time history, measured from the model test, is decomposed into wavelet basis function targeting the minimization of the number of the basis function together with the maximization of the numerical efficiency. Then the response of the structure is obtained using the finite element method under each wavelet basis function of different scale. Finally, the response of the structure under entire sloshing impact time history is rapidly calculated by synthesizing the structural response under wavelet basis function. Through this analysis, more realistic response of the system under sloshing impact pressure can be obtained without missing the details of pressure time history such as rising pattern, oscillation due to air entrapment and decay pattern and so on. The strength assessment of the cargo containment system is then performed based on the statistical analysis of the stress peaks selected out of the obtained stress time history.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.129-149
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• 2019

This study is to give a three-dimensional view of the concept of rurality and ruralness in terms of time-span, perceived object and awareness level. In the precedent studies ruralness or rurality has been approached as the category of usefulness resources called amenity. This overlooked the perceived representation, institutional reference and rurality of ideological values. Rurality appears as a cumulative representation of being rural from the past to the present, but ruralness exists as a desirable form or value for the future. Through this study, it has been analyzed that ruralness consists of six realms such as environment, community, self-reliance, aesthetics, enjoyable amenity and settlement, and of three or four sub-realms by each amounting to 20 in total. According to the vocabulary listing by the survey to 30 experts, rurality for the past-present is mainly imagined as of natural environment, agriculture, landscape, and community history, while ruralness for the future is frequently described as of communities, settlement and self-reliance by number of references. Through the vocabulary extraction, 17 words in the level of mid-conception are induced including ecology, comfort, history, agriculture, landscape, place, culture, convenience, etc. In conclusion the concept of ruralness along with rurality could be organized into three different layers of perception consisting of representation, norms and usefulness.