• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.23-31
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• 2004

Temperature variations, and carbon dioxide and methane concentrations are summarized during the past 400,000 years. Atmospheric temperature varied approximately within $10^{\circ}C$ during the past 400,000 years. Most of the time during the past 400,000 years, temperature was lower than today except 410000, 320000, 250000, and 125000 years ago. Temperature was slightly higher or at least similar to today during the time period of 410000. 320000, 250000, and 125000 years ago. The carbon dioxide concentration varied between 180 and 300 ppm, and the methane concentration varied between 40 and 700ppb. The present atmospheric concentration of carbon dioxide is 375 ppm and methane is 1750 ppb. Temperature was 5-$7^{\circ}C$ lower than today during the Last Glacial Maximum(18,000 years ago) and the Younger Dryas(10,000 years ago). Temprature was varied within $1^{\circ}C$ during the past 10,000 years. Especially Middle Holocene Climatic Optimum(6,000 years ago), Medieval Warm Period (500-1,000 years ago), and Little Ice Age(100-500 year ago) were global climatic events. In general, mechanism for the Middle Holocene Climatic Optimum, Medical Warm Period, and Little Ice Age can be explained by the solar insulation, however their exact mechnism is not well known. Carbon dioxide concentration during the past 400,000 years never reached the current value of 375 ppm. Furthermore, the current methane concentration never reached during the past 20Ma. However, current temperature value has happened several times during the past 400,000 years. The implication of this is unsolved question so far. This should be challenged in the near future.

• The Korean Journal of Quaternary Research
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• v.8 no.1
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• pp.9-22
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• 1994

The vegetational and environmental history of Korea during the Holocene period has reconstructed by the use of folral, palaeoclimatogical, archaeological data and written records. From 10,000 to 6,700 yeat B.P. in mid-eastern Korea, deciduous broadieaved trees gradually increased trees, notably at c.8,000 years B.P. From 6,700 to 4,500 years B.P., the vegetation remained dominated by Quercus and pinus(Diploxylon). Vegetational informations suggest the postglacial hypsithermal from c.8,000 to 4,500 years b.p. After 4,500 until 1,400 years B.P., the admixture of cryophilous trees in midland and thermophilous trees in south seems to imply the latitudinal divisions of vegetation and climate. The presence of cultivated rice pollen as well as non-arboreal pollen and spores indicates an increased rate of deforestation. From 1,400 years B.P., there was a sharp decrease in the representation of temperate trees, but the presence of the cryophilous genera Abies and pinus (Haploxylon) is noticea-ble and might be related to the occurrence of Little Ice Age. Fossil pollen diagram from western Korea and eastern Korea since 6,250 and 10,000 yeats B.P., respectively have enabled to compare vegetational dis-tribution patterns and changes in the Holocene period. In western Korea, Alnus- dominated vegetation continued from 6,250 to 1,500 years B.P., but pinus took over Alnus from 1,500 years B.P. In eastern Korea, however, Quercus and pinus dominated from 10,000 to 2,000 years B.P., but pinus be-came predominant from 2,000 years B.P. On a time- spatial basis, different vegetational distribution pattern can be recognised between western and east-ern Korea. The use of seven historical records which is unique to Korea also enabled to reconstruct the distributional pattern and temporal change of vegetation from 1425 to 1928.

• Journal of Nutrition and Health
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• v.41 no.1
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• pp.77-88
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• 2008

This research was carried out a to investigate the food habit and preference of parents' social and economic level with 681 children (145 of Kindergarten, 300 of Children, 236 of Adolescences) in Seoul and Gyeonggi area using question naires. The parents' income level divided into 2 groups, less than 4 million won and equal or greater than 4 million won. Most of the middle years were over-weighing but kindergarten and adolescences had standard weights. The majority of parents had Bachelor degrees, most of father were office workers, majority of mothers of kindergarten with parents' income level less than 4 million won were professional women and mothers of the rest of the groups were mostly house wives. The middle years with parents income level less than 4 million son were skipping meals most frequently, but other groups didn't show much differences in their eating habits. All age groups showed that they like meats the most and dislike vegetables the worst. All age groups also showed that they mostly eat out 1-2 times a week and the next was 3-4 times a week. All age groups preferred ice creams, fruits, juices and snacks for their desserts. The middle years with parents' income equal or greater than 4 million won also showed high preference on strawberry and chocolate flavored milk, burgers and pizzas. The food s that preferred to eat when dining out were Chinese foods (Ja-jang-myeon and sweet and sour pork) for kindergarten group, Korean foods (kalbi and bulgogi) for the middle years with parents' income level less than 4 million won, family restaurant food (steak and rib) for the middle years with parents' income level equal or greater than 4 million won and Korean foods (kalbi and bulgogi) for the adolescences. The preferred cooking methods were roast (fish and sea weeds) for the kindergarten, roasted meat for the middle years, Kimchi and bean paste pot stew for the adolescences with parents' income level less than 4 million won and roasted meats for the adolescences with parents' income level equal or greater than 4 million won. The results showed that the adolescences with higher parental income lever preferred meats.

• The korean journal of orthodontics
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• v.54 no.3
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• pp.185-195
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• 2024

Objective: This study aimed to retrospectively analyze the prevalence of orthodontic problems and the proportion of patients who underwent orthodontic diagnosis among children aged 6 (n = 300), 7 (n = 400), and 8 (n = 400) years who had undergone panoramic radiography. Methods: Children were divided into five groups according to their chief complaint and consultation: conservative dentistry, oral and maxillofacial surgery, orthodontics, periodontics, and prosthodontics). Chief complaints investigated included first molar eruption, lack of space for incisor eruption, frequency of eruption problems, lack of space, impaction, supernumerary teeth (SNT), missing teeth, and ectropion eruption. The number of patients whose chief complaint was not related to orthodontics but had dental problems requiring orthodontic treatment was counted. The proportion of patients with orthodontic problems who received an orthodontic diagnosis was also examined. Results: Dental trauma and SNT were the most frequent chief complaints among the children. The proportion of patients with orthodontic problems increased with age. However, the orthodontic diagnosis rates based on panoramic radiographs among children aged 6, 7, 8 years were only 1.5% (6 years) and 23% (7 and 8 years). Conclusions: Accurate information should be provided to patient caregivers to correct misconceptions regarding the appropriateness of delaying orthodontic examination until permanent dentition is established.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.69-83
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• 2014

This study examines vegetation and climate changes from pollen compositions of alpine moors in the Korean Peninsula such as Mujechineup at Mt. Jeongjok, Yongneup at Mt. Daeam, Jilmoineup at Mt. Odae and Wangdeungjaeneup at Mt. Jiri including moors at Mt. Jeombong. It can be found that the alpine moors were less interfered by human than low moors during the past 2,000 years of the historical age. Based on dominant periods of Pinus and Quercus, pollen compositions of the alpine wetlands, climatic environments of vegetation and historical records, vegetation and climate changes during three periods such as approximately 2,000~1,000 yr BP, 1,000~400 yr BP and 400 yr BP~present are examined. It was warmer during the period of 1,000~400 yr BP than 2,000~1,000 yr BP. The period of approximately 400 yr BP indicate the coldest climate of Little Ice Age. This study finds dominances of Quercus, low NAP/AP ratios, obvious divisions of pollen zones and human interference after 400 yr BP from pollen compositions of the alpine moors during the historical age. Human interference in the high moors becomes obvious after approximately 400 yr BP, indicating that there is a time lack of approximately 1,500~2,000 years between the alpine and low moors.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.127-137
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• 2017

Sally Potter's movie, Orlando is a bold re-make of Virginia Woolf's classic novel, Orlando: A Biography, in which an English nobleman survives 400 years - as a man and then a woman. This paper focuses on a study of the film of Orlando in light of the feministic view. In Woolf's gender-bending, time-traveling novel, Orlando, Woolf probes the ideology of patriarchal society through an androgynous persona. Sally Potter's adroit revision of Woolf's novel not only duplicates Woolf's Orlando but it also catches Woolf's feminism by using cinematic expertise. The film is incredibly true to Woolf's spirit. The most explicit changes were structural so the storyline was simplified. Thus Orlando gives us a license to travel freely from a man to a woman. In short, Orlando is not about feminism but the unity and harmony of male and female.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.257-262
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• 1981

Field experiment with 0, 100, 200, 400, and 800 kg-N/ha-year application levels was carried out to study the nitrogen response in the early stage of orchardgrass pasture establishment at College Fann, SNU, in 1979 and 1980. Both the highest dry matter yield and maximum percent of N recovery were obtained at the same level of 200 kg-N/ha in the year of seeding. but those of the next year were obtained at 400 kg-N/ha level. Leaf area indices (LAI) and net assimilation rates (NAR) during each regrowth periods as well as total nitrogen contents of forage at each cutting time increased with applied N in both years. The maximum crop growth rate (CGR) over two years was estimated to be obtained when LAI reached to about 5. The accumulation of NO_3 -N in forage started from 400kgㆍN/ha application in 1980. and exceeded the safe level for ruminants at the level of 800 kg-N/ha.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2190-2199
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• 2009

Nihombashi is located in the central area of Tokyo, Japan. Tokyo has been the capital in Japan since the Edo period, which started approximately 400 years ago, and has accepted a variety of cultures, human resources, businesses for the last 400 years. This has resulted in building up the present prosperity. The Sumida River, one of the symbols of Tokyo and its tributaries including the Kanda River and the Nihombashi River, flows through the Nihombashi district. The river and tributaries used to benefit to the City of Edo. Due to the economic development and the industrial growth in Tokyo, however, they were polluted and lost their functions. In 1960s, approximately 40 years ago, the Sumida River became so dirty that local citizens kept away from it. The Nihombashi River was covered with an expressway, which was obscuring the river view. Since 1970s, local communities have proposed to rehabilitate rivers in Tokyo successively, and have proceeded with measures for river floods, improvement of sewage systems and construction of water purification facilities. Consequently, the quality of the river water was considerably improved in 1990. The stagnant rivers were turned into ones that local citizens were physically able to come close by. Today, restoring of the environment and the appearance of the city in the old days, Nihombashi district has been proposed as a model city of the future, which is alive with history and culture and harmonizing with rivers. The concept is "To Create, To Reserve, To Restore." This paper introduces a case study of the urban development, in which the local communities and public authorities collaborated with and proposed a brand-new style of the urban city harmonizing with the environment.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.679-684
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• 2017

Recently, the speed of high-speed railway has been rapidly increase with the development of high-speed train design and operating technology. This causes a lot of complaints related the environmental noise in residential areas near the high-speed railway. In order to operate the high-speed railway in accordance with the design speed, noise reduction technology should be developed to meet the noise characteristics of high-speed railway. And it is important to develop the prediction technology by grasping the noise radiation characteristics. In order to meet these requirements, in recent years, infra-research for 400 km/h high speed railway has been conducted. Reliable noise prediction and noise reduction techniques have been developed through this study. This paper is concerned with wind pressure safety and noise performance evaluation of the newly developed 400 km/h noise reduction device. The wind pressure safety and The noise performance of the developed device was confirmed by this paper.

• Journal of Ecology and Environment
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• v.34 no.3
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• pp.259-267
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• 2011

A pollen analytical study of sediment sequences collected from Yongneup moor (sampling point: $38^{\circ}$12'57.4" N, $120^{\circ}$7'30.2" E) was conducted to understand the vegetation history in the mountainous region of the central Korean peninsula. Carbon dating was carried out to measure five successive samples obtained from the bottom at a depth of 180 cm to the surface. The Yongneup moor sediment revealed four main local pollen zones; that is, four past vegetation phases as follows: Local pollen zone I: Quercus-Pinus zone; estimated age, 5,900-4,800 calibrated years (cal) before present (BP); vegetation type, cool-temperate central/montane deciduous broad-leaved forest. Local pollen zone II: Pinus-Abies-Quercus zone; estimated age, 4,800-3,400 cal BP; vegetation type, cool-temperate northern/alti-montane mixed coniferous and deciduous broad-leaved forest. Local pollen zone III: Quercus-Pinus-Abies zone; estimated age, 3,400-400 cal BP; vegetation type: cool-temperate central/montane deciduous broad-leaved forest. Local pollen zone IV: Pinus-Quercus zone; estimated age, 400-present cal BP; vegetation type, cool-temperate central/montane mixed deciduous broad-leaved and coniferous forest. It was confirmed that subalpine coniferous forests had expanded to the mountainous region of the central Korean peninsula during the period from 4,800-3,400 cal BP and thereafter deciduous forests dominated by Q. mongolica were established. Notably, secondary forests dominated by P. densiflora developed in the lower part of the mountainous region of the central Korean peninsula about 400 cal BP due to human interference.