• Title/Summary/Keyword: ancient solutions

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ANCIENT SOLUTIONS OF CODIMENSION TWO SURFACES WITH CURVATURE PINCHING IN ℝ4

  • Ji, Zhengchao
    • Bulletin of the Korean Mathematical Society
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    • v.57 no.4
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    • pp.1049-1060
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    • 2020
  • We prove rigidity theorems for ancient solutions of geometric flows of immersed submanifolds. Specifically, we find conditions on the second fundamental form that characterize the shrinking sphere among compact ancient solutions for the mean curvature flow in codimension two surfaces, which is different from the conditions of Risa and Sinestrari in [26] and we also remove the condition that the second fundamental form is uniformly bounded when t ∈ (-∞, -1).

Solutions of Equations in Chosun Mathematics (조선산학(朝鮮算學)의 방정식 해법(解法))

  • Kim, Chang-Il;Yun, Hye-Soon
    • Journal for History of Mathematics
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    • v.22 no.4
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    • pp.29-40
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    • 2009
  • we know that Zeng Cheng Kai Fang Fa is the generalization of the method of square roots and cube roots of ancient through the investigation of China mathematics. In this paper, we have research on traditional solutions equations of China mathematics and the development solutions of equations used by Chosun mathematicians.

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Historical and Social Environments and the Structure of The Nine Chapters on the Mathematical Art (역사(歷史) 사회(社會) 환경(環境)과 구장산술(九章算術의) 구조(構造))

  • Kang, Shin-Won
    • Journal for History of Mathematics
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    • v.19 no.4
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    • pp.1-12
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    • 2006
  • The Nine Chapters on the Mathematical Art has dominated the history of Chinese mathematics. It served as a textbook not only in China but also in the neighbouring countries and regions. The book is anonymous like many Chinese classics. The Nine Chapters contains 246 problems and their solutions, some of which date back to before the Qin Dynasty $(221\sim207\;B.C)$ and it seems to have been written by various writers over many generations. In this paper, we will investigate the structure of the Nine Chapters from the view points of ancient social environments which entail eventually mathematics in the Nine Chapters.

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An Evaluation on the Physical and Psychological Image of Insa-Dong (인사동의 물리적 심리적 이미지의 평가)

  • 조정숙;김남조
    • Journal of the Korean Institute of Landscape Architecture
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    • v.30 no.2
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    • pp.12-22
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    • 2002
  • This study examines the visitors'evaluations of tourism resources in Insa-dong, which the Seoul metropolitan government has improved recently. This study adopted the method of Importance-Performance Analysis by collecting data through questionnaires. A random sampling of visitors to Insa-dong was conducted in June and July,2001. The survey included questions on the physical and psychological components of Insa-dong's tourism resources. In the case of physical components, eight factors(ancient arts shop, art gallery, atelier, calligraphy shop, pottery arts, traditional tea house, antique shop, traditional clothes) out of thirteen were categorized as 'keeping up the good work'. None of the Physical components was shown as 'low priority'or'possible overkill'. In particular, four factors(restaurant, heritage, Korean-style house and alley, traditional cultural festival) need to be impoved most urgently in terms of visitors'satisfaction. Survey results realize them as high priority in importance but low in performance, thereby designated as, 'concentrate here'. An image of the 'street' showed to be high in importance and identical in performance, so can be categorized between'keeping up the good work'and 'concentrate here'. The results show that unusual outdoor spaces and the festivals of Insa-dong have a significant meaning to the visitors. In the case of psychological components, three factors(general atmosphere experience of unusual atmosphere, appropriateness of stroll time) out of seventeen were categorized as 'keeping up the good work'. Ore factor (shopping) was designated as 'low priority'and not found to be 'possible overkill'. Thirteen factors (various events, possibility of various activity, various flood, richness of play, new experience, education cultural inheritance, parking facilities, resting places, green spaces, meeting places, guide map and information, cleanliness of facilities/convenience) need to be improved mast urgently in terms of visitors' fulfillment. They are perceived as areas of 'concentrate here'. This confirms that attractive events are essential for the recent visitor satisfaction. Furthermore, visitors are not satisfied with its amenity and acccss in Insa-dong despite the improvements. In conclusion, positive impressions, both physical and psychological, should be maintained while factors mentioned to be lacking should be prioritized in order of necessity to improve the image of Insa-dong and solutions need to be found and implemented. The results of this study would be helpful in the planning and management of nsa-dong considering the visitors'requirements.

The Characteristics of Natural Hazard due to the Impact of Urbanization in Seoul Metropolitan Area : A potential flood hazard study of Anyang-Cheon Watershed (수도권지역 개발에 따른 자연재해 특징분석 : 안양천 유역분지에서 잠재적 수해특성 분석)

  • 성효현
    • Spatial Information Research
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    • v.4 no.1
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    • pp.21-42
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    • 1996
  • The Anyang-cheon is one of the Han River tributaries in Seoul Metropolitan area. It is 35.1km long, has a basin area of 287km2 and touches seven cities of Kyounggi Province and part of Seoul. The purpose of this study were 1) to reconstruct the ancient stream network and to investigate the change of landuse in Anyang-cheon watershed between 1957 and 1991,2) to measure the change of the hydrologic ¬acteristics with urbanization, 3) to suggest the institutional solutions to reduce natural hazard as the area has urbanizedThe main results are as follows: 1.Anyang-cheon river basin has experienced the rapid urbanization and industrialization since 1957. Anyang-cheon stream network was oversimplified in the watershed. The total stream length decreased atributaries in the upper part of river basin have eliminated or buried undergrolmd in pipes. 2.Urbanization impacted to all of the area of Anyang-cht'On watershed. Urbanization in Anyang-cheon watershed corresponds to the large portion of flat area, especially flood - prone zone of river side, and the small portion of Greenbelt to constrain urban expantion in cities. 3.The urbanization of Anyang-cheon watershed produces fundamental changes in watershed hydrology. As infiltration is reduced by the creation of extensive pavement, concrete surface, and sewer pipe, runoff moves more quickly from upland to stream. As a result, runoff from the watershed is flashier, increasing flood hazardAs urban area continue to grow we will need to better utilize stream by protecting and enhancing stream systems.otecting and enhancing stream systems.tems.

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Preservation of World Records Heritage in Korea and Further Registry (한국의 세계기록유산 보존 현황 및 과제)

  • Kim, Sung-Soo
    • Journal of Korean Society of Archives and Records Management
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    • v.5 no.2
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    • pp.27-48
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    • 2005
  • This study investigates the current preservation and management of four records and documentary heritage in Korea that is in the UNESCO's Memory of the World Register. The study analyzes their problems and corresponding solutions in digitizing those world records heritages. This study also reviews additional four documentary books in Korea that are in the wish list to add to UNESCO's Memory of the World Register. This study is organized as the following: Chapter 2 examines the value and meanings of world records and documentary heritage in Korea. The registry requirements and procedures of UNESCO's Memory of the World Register are examined. The currently registered records of Korea include Hunmin-Chongum, the Annals of the Choson Dynasty, the Diaries of the Royal Secretariat (Seungjeongwon Ilgi), and Buljo- Jikji-Simche-Yojeol (vol. II). These records heritage's worth and significance are carefully analyzed. For example, Hunmin-Chongum("訓民正音") is consisted of unique and systematic letters. Letters were delicately explained with examples in its original manual at the time of letter's creation, which is an unparalleled case in the world documentary history. The Annals of the Choson Dynasty("朝鮮王朝實錄") are the most comprehensive historic documents that contain the longest period of time in history. Their truthfulness and reliability in describing history give credits to the annals. The Royal Secretariat Diary (called Seungjeongwon-Ilgi("承政院日記")) is the most voluminous primary resources in history, superior to the Annals of Choson Dynasty and Twenty Five Histories in China. Jikji("直指") is the oldest existing book published by movable metal print sets in the world. It evidences the beginning of metal printing in the world printing history and is worthy of being as world heritage. The review of the four registered records confirms that they are valuable world documentary heritage that transfers culture of mankind to next generations and should be preserved carefully and safely without deterioration or loss. Chapter 3 investigates the current status of preservation and management of three repositories that store the four registered records in Korea. The repositories include Kyujanggak Archives in Seoul National University, Pusan Records and Information Center of National Records and Archives Service, and Gansong Art Museum. The quality of their preservation and management are excellent in all of three institutions by the following aspects: 1) detailed security measures are close to perfection 2) archiving practices are very careful by using a special stack room in steady temperature and humidity and depositing it in stack or archival box made of paulownia tree and 3) fire prevention, lighting, and fumigation are thoroughly prepared. Chapter 4 summarizes the status quo of digitization projects of records heritage in Korea. The most important issue related to digitization and database construction on Korean records heritage is likely to set up the standardization of digitization processes and facilities. It is urgently necessary to develop comprehensive standard systems for digitization. Two institutions are closely interested in these tasks: 1) the National Records and Archives Service experienced in developing government records management systems; and 2) the Cultural Heritage Administration interested in digitization of Korean old documents. In collaboration of these two institutions, a new standard system will be designed for digitizing records heritage on Korean Studies. Chapter 5 deals with additional Korean records heritage in the wish list for UNESCO's Memory of the World Register, including: 1) Wooden Printing Blocks(經板) of Koryo-Taejangkyong(高麗大藏經) in Haein Temple(海印寺); 2) Dongui-Bogam("東醫寶鑑") 3) Samguk-Yusa("三國遺事") and 4) Mugujeonggwangdaedaranigyeong. Their world value and importance are examined as followings. Wooden Printing Blocks of Koryo-Taejangkyong in Haein Temple is the worldly oldest wooden printing block of cannon of Buddhism that still exist and was created over 750 years ago. It needs a special conservation treatment to disinfect germs residing in surface and inside of wooden plates. Otherwise, it may be damaged seriously. For its effective conservation and preservation, we hope that UNESCO and Government will schedule special care and budget and join the list of Memory of the Word Register. Dongui-Bogam is the most comprehensive and well-written medical book in the Korean history, summarizing all medical books in Korea and China from the Ancient Times through the early 17th century and concentrating on Korean herb medicine and prescriptions. It is proved as the best clinical guidebook in the 17th century for doctors and practitioners to easily use. The book was also published in China and Japan in the 18th century and greatly influenced the development of practical clinic and medical research in Asia at that time. This is why Dongui Bogam is in the wish list to register to the Memory of the World. Samguk-Yusa is evaluated as one of the most comprehensive history books and treasure sources in Korea, which illustrates foundations of Korean people and covers histories and cultures of ancient Korean peninsula and nearby countries. The book contains the oldest fixed form verse, called Hyang-Ka(鄕歌), and became the origin of Korean literature. In particular, the section of Gi-ee(紀異篇) describes the historical processes of dynasty transition from the first dynasty Gochosun(古朝鮮) to Goguryeo(高句麗) and illustrates the identity of Korean people from its historical origin. This book is worthy of adding to the Memory of the World Register. Mugujeonggwangdaedaranigyeong is the oldest book printed by wooden type plates, and it is estimated to print in between 706 and 751. It contains several reasons and evidence to be worthy of adding to the list of the Memory of the World. It is the greatest documentary heritage that represents the first wooden printing book that still exists in the world as well as illustrates the history of wooden printing in Korea.