• The Journal of the Petrological Society of Korea
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• v.14 no.3 s.41
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• pp.149-156
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• 2005

Ar-Ar, carbon AMS and OSL dating was carried out to clarify the age of the human footmarks on the Hamori Formation, Jeju Island, Korea. $^{40}Ar/^{39}Ar$ ages of trachybasalt from the Songaksan Tuff, which is underlain by the Hamori Formation, range between $10.6{\pm}19.9\;Ka$ and $11.7{\pm}26.3\;Ka$. Radiocarbon AMS ages of humin fractions extracted from sediment samples yielded the maximum limit age of the Hamori Formation as $15,161{\pm}70\;yr$ B.P. The OSL dating of the top and bottom layers of the Hamori Formation gave $6.8{\pm}0.3\;ka$ and $7.6{\pm}0.5\;ka$, respectively, suggesting that timing of the human footmarks formation can be constrained as between ca 6,800 yr B.P. and 7,600 yr B.P.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• Korean Journal of Plant Resources
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• v.20 no.5
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• pp.424-436
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• 2007

In this paper, it was discussed situations and necessities of conservation management strategy for the woody plants resources in Jeju Island. Out of 320 taxa of the woody plants distributed in Jeju, there were 62 families, 136 genus, 279 species, 28 varieties and 13 forma. Conifers, gymnosperms, were 3 families, 5 genus and 7 species as holding 2.2% of total woody plants. Broad leaves, angiosperms, were 59 families, 131 genus, 272 species, 28 varieties and 13 forma that were 313 taxa. Evergreens were 84 taxa consisting of 31 families, 45 genus, 72 species, 7 varieties and 5 forma that make up 26.8% out of total angiosperms. Deciduous were 229 taxa(73.2%) consisting of 42 families, 93 genus, 200 species, 21 varieties and 8 forma that were 122 trees(38.1%), 177 shrubs(55.1%) and 21 vine plants(6.8%). Life form spectra by dormancy, disseminule, radicoid and growth form were analysed. Thirty eight taxa including 17 families, 21 genus, 14 species and 16 varieties out of 320 taxa growing Jeju were endemic to Korea and 22 taxa of them were endemic to Jeju. The specific plant species among the woody plants in Jeju were 10 taxa in V grade, 24 taxa in IV grade and 53 taxa in III grade. These are correspondence to those of nations as 12% of V grade, 7.6% of IV grade and 17.2% of III grade.

• The Korean Journal of Mycology
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• v.31 no.3
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• pp.134-140
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• 2003

Wild Mushrooms collected in Mt. Halla of Jeiu Island around altitude of $200{\sim}1000\;m$ from 1999 to 2000 were studied to investigate utilization as the natural breeding sites by wild drosophilids. Thirty-five mushroom species belonging to the 19 genera of 12 families from 2 orders were used as natural breeding sites by drosophilids. Adult flies emerged from 14 species of mushrooms belonging to the 11 genera of 8 families from 2 orders were identified. From the rest of 21 species of mushrooms, only larvae or/and pupae were reaped. Among 35 species of mushrooms, 34 species belonged to order Agaricales and only one species, Sarcodon scabrosum, belonged to order Aphyllophorales. In terms of composition of mushroom families, total 35 species belonging to 12 families were composed of 10 species of Russulaceae, 6 species of Amanitaceae, 4 species of each Tricholomataceae and Agaricaceae, 3 species of Boletaceae, 2 species of Strophariaceae and each one species of rest 6 families. Concerning the composition of the genus, 35 species belonging to 11 genera were composed of 8 species of Russula, 6 species of Amanita, 4 species of Agaricus, 2 species of Lactarius, and each one species of rest 7 genera. In terms of the mushroomsize preference of drosophilid flies for breeding sites, most flies preferred comparatively large mushrooms above 5 cm of pileus size in diameter, Fourteen species of drosophilids were identified as mushroom-breeding species. Among these, one and five species belonged to genera Mycodrosophila and Hirtodrosophila respectively, The genus Drosophila included the most abundant 8 species. Drosophila bizonata and Hirtodrosophila sexvittata bred on 6 species of mushrooms respectively, D. unispina bred on 3 species of mushrooms, rest species of Drosophila bred on one or two species of mushrooms. From the result of this study and other literatures, it could be presumed that much more mushroom species could serve as the natural breeding sites for greater number of drosophilid species than those examined in this study on Jeju Island.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.248-253
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• 2002

This study was to provide information about snow falling phenomenon in Korea for 1934 years from BC 6 to 1928 based on the records of old literatures, which are the true record of the Chosun dynasty, records of king Kojong and Soonjong, and some data including history of the Koryo in internet home page of Korea meteorological administration. Key words used in search procedure were totally 20 words such as snow, heavy snow, big snow, snow pellets, snowstorm, avalanche, etc. The searching contents consisted of the time of the first and the last snow, the amount of snow falling, snow damage, the thought about heavy snow phenomenon, and unusual weather conditions related to snow. The earliest record for the first snow was July of the rural calendar in 733 and the latest record for the last snow was June 11 of the lunar calendar. From these records, it could be estimated that there were some snow falling even in summer season. The amount of almost heavy snow ranged from 1.2 m to 1.5 m, but sometimes there were some records about the amount of snow falling higher than 3 meters. It was also found that there were three records about big heavy snow damages. In 1524 and 1525, approximately 100 and 140 peoples in Kyungsung, Hamgyung Province were dead due to heavy snowstorm. It was also recorded that 91 people in Jeiu island were dead in 1670 because of snow damage. Some singular records about snow were also found in old literatures. There was a congratulatory ceremony of new snow when the first snow was falling in the year. There was also a ritual praying for snow when there was no snow in the year. It was also found that there was snow falling with worms and red snow falling.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.23-30
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• 2002

Eveuadies 71' kenaf (Hibiscus cannabinus L.) was grown at five plant densities (1, 2, 3, 4, and 5 plants per hill; 16,000, 32,000, 48,000, 64,000 and 80,000 plants/10a) from April 13 to October 8, 2001 in Jeju island to determine influence of plant number per hill on agronomic characteristics, forage yield and quality. As plant density increased from 1 to 5 plants per hill, the plant height averaged across two harvests increased 176 to 185 cm. Compared with the plant density of two plants per hill, the plant height decreased at higher plant densities (183, 180, and 166 cm for 3, 4 and 5 plants per hill). The highest yield of fresh forage (114.6 MT/ha), dry matter (17.3 MT/ha), crude protein (2.33 MT/ha), and total digestible nutrients (TDN) (9.21 MT/ha) was obtained at 2 plants per hill. As plant density increased from 1 to 5 plants per hill, crude protein, ether extract, nitrogen free extract, and TDN contents increased from 13.1 to 15.4%, 3.0 to 3.7%, 20.1 to 23.2% and 41.1 to 45.4%, respectively, while crude fiber and crude ash contents decreased from 41.2 to 34.9% and 9.4 to 8.2%, respectively.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.435-456
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• 2006

This study examines the long-term spatial patterns and recent trends of seasonal onsets and durations defined by daily temperatures in South Korea for the period 1973-2004. Spatially, spring and winter onset dates show approximately 44 day and 63 day maximum difference respectively between south and north (Seongsanpo to Daegwallryeong) attributable to the impacts of latitudes and altitudes. In contrast, summer onset, which is more affected by proximity to oceans and altitudes than by latitudes, begins earlier in interior low elevated areas than in the coastal areas but earliest at higher latitudes than Jeiu Island. Five climatic types regarding the seasonal cycles in South Korea are spatially clustered according to the combination of longer seasonal durations. As a reflection of recent climate changes on seasonal cycles in South Korea, winter duration was shortened by 10 days during the post-1988 period due to a late winter onset of 4 days and an early spring onset of 6 days. The winter reduction began in the southern regions of the Korean Peninsula in the mid-1980s and spread northward during the 1990s period, ultimately appearing everywhere. In urbanized cities, where much of the surface is covered with asphalt or concrete, the winter reduction was intensified and summer duration was locally incremented. The reduced winter duration in recent decades shows significant teleconnections with variations of geopotential height (925hPa) in the eastern Arctic region ($0-90^{\circ}E$, $65-85^{\circ}N$) during the cold season. The reduction in winter duration in South Korea agrees with results in overall global warming trends as a climate change signal.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.328-338
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• 2022

This study aims to identify the influential relationship between the characteristics of tourism information of the MZ generation's SNS content, tourist destination reputation, and intentions of traveling behavior with a focus on Jeju Province. To achieve the purpose of this research, this study was conducted on 270 tourists who had recently traveled to Jeju Island after being exposed to characteristic tourism information on SNS within the last year among the MZ generation through a commissioned survey company. A total of 270 results were collected and used for empirical analysis. The results of the research are as follows. First, it was found that the reliability, usefulness, timeliness, and interactivity factors of SNS tourism information had a significantly positive (+) effect on the reputation of the tourist destination. Second, it was found that the reliability, usefulness, timeliness, and interactivity factors of SNS tourism information had a significantly positive (+) effect on the intentions of traveling behavior. Third, it was found that the tourist destination reputation has a positive (+) effect on the intentions of traveling behavior. This study discussed the future tourist destination reputation formation and future behavioral decision process of the MZ generation tourists who are constantly seeking tourist destinations. In addition, the theoretical implications presented in this study were discussed.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.299-311
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• 2006

In this paper it is outlined the methodology of estimating the parameters of water balance analysis method for calculating recharge, using ground water level rises in monitoring well when values of specific yield of aquifer are not available. This methodology is applied for two monitoring wells of the case study area in northern area of the Jeiu Island. A water balance of soil layer of plant rooting zone is computed on a daily basis in the following manner. Diect runoff is estimated by using SCS method. Potential evapotranspiration calculated with Penman-Monteith equation is multiplied by crop coefficients($K_c$) and water stress coefficient to compute actual evapotranspiration(AET). Daily runoff and AET is subtracted from the rainfall plus the soil water storage of the previous day. Soil water remaining above soil water retention capacity(SWRC) is assumed to be recharge. Parameters such as the SCS curve number, SWRC and Kc are estimated from a linear relationship between water level rise and recharge for rainfall events. The upper threshold value of specific yield($n_m$) at the monitoring well location is derived from the relationship between rainfall and the resulting water level rise. The specific yield($n_c$) and the coefficient of determination ($R^2$) are calculated from a linear relationship between observed water level rise and calculated recharge for the different simulations. A set of parameter values with maximum value of $R^2$ is selected among parameter values with calculated specific yield($n_c$) less than the upper threshold value of specific yield($n_m$). Results applied for two monitoring wells show that the 81% of variance of the observed water level rises are explained by calculated recharge with the estimated parameters. It is shown that the data of groundwater level is useful in estimating the parameter of water balance analysis method for calculating recharge.

• Applied Biological Chemistry
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• v.9
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• pp.41-57
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• 1968

Changes of acids (total, titratable and combined form) and sugars (total, reducing and non-reducing) in the edible part and the rind of 17 varieties the in growing and ripening period were investigated. The results were summarized as follows. 1) The percentage of rind was notably decreased in growing period and slightly in the ripening period- It may suggest that the rates of translocation of metabolite from leaves to each part of fruit are different with growth phase. 2) The heavier the weight of fruit, the higher the percentage of rind was and the varieties having over 200 g per fruit showed the value over 30 in the rind percentage and over 15 in the number seeds per fruit. 3) Total acid contents in the rind were highest at the maximum grow th of fruit except in Citrus grandis having tie lowest value (below 20 me/100 g F.W). of total acid at maximum point in which total acid content is steadily increase. 4) Total acid and titratable acid in the edible part and total acid and combined acid in whole fruit life showed 0.933 and 0.970 of correlation coefficient significant at 1% level respectively, and most acid in the edible part was titratable acid(73%) whereas acid in the rind consists mostly of combined acid. 5) The content of combined acid in the ripening period increased in the edible part and decreased in the rind. It may be contributed to translocation of some cations from the rind to the edible part. 6) The grouping criteria on citrus fruit were applicable on melon, watermelon and tomatoes. 7) The contents of total sugar and non-reducing sugar in the edible part were continuously increased whereas the content of reducing sugar were decreased in certain varieties, notablly in citrus natsudaidai. The correlation coefficient between total sugar and reducing sugar in the edible part with ripening decreased as $0.849^{**},\;0.732^{**}.\;0.583^*$. ( $^{**}$: significant at 1% level and $^{*}:$: at 5%) 8) 61% of total sugar in the edible part was non-reducing sugar whereas 88% of total sugar in the rind was reducing form at the end of ripening and the correlation coefficient between total and non-reducing sugar in the edible part was 0.861 end total and reducing sugar in the rind was 0.972, both significant at 1% level. 9) Varieties having the percentage of the rind below 36 showed higher value than I in the ratio of total sugar in the edible part to one in the rind. It may suggest that there exists any intimate relation between relative sugar content and growth rate of fruit parts. 10) Citrus unshiu in Guje island showed lower values in the content of acid and sugar, and the rind percentage but higher sweetness index (the ratio of total sugar to titratable acid) comparing with the same variety in Jeiu.