• Korean Journal of Environment and Ecology
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• v.33 no.6
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• pp.636-644
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• 2019

The purpose of this study was to investigate the callings of nocturnal birds using bioacoustic recording technology to identify species and to analyze the ecological characteristics of each species. Three sites - Seoraksan National Park, National Institute of Ecology, and Mudeungsan National Park - were investigated. The investigation period was from the middle of April 2018 to early March 2019 for Seoraksan national park, from late February of 2018 to the middle of February 2019 for the National Institute of Ecology, and from the middle of February 2018 to the end of August 2018 for Mudeungsan National Park. The main research results are as follows. Firstly, nocturnal bird species identified by the survey included Caprimulgus indicus, Otus sunia, Zoothera aurea, Bubo bubo, and Strix uralensis, 5 species in total. Secondly, the breeding call period of each species was from early May to early August for C. indicus, from early April to the end of September for O. sunia, from early March to early October for Z. aurea, from late September to early February for B. bubo, and from mid-January to early March for S. uralensis. Thirdly, the mating call rhythm was between 16:00 and 10:00 on the following day for all the observed species in the three regions, and the peak time zone was from 20:00 to 06:00 on the following day. Fourthly, there was no correlation between the cumulative call frequency and the precipitation for each species. Fifthly, the mean temperature during the period when the specific calls of nocturnal birds were detected was -4.00 ℃ for S. uralensis, 2.58 ℃ for B. bubo, 13.66 ℃ for Z. aurea, 19.50 ℃ for O. sunia, and 20.77 ℃ for C. indicus. The ANOVA results showed that there was a significant difference in mean temperature for the calling by species and that the mean temperature was S. uralensis, B. bubo, Z. aurea, and O. sunia-C. indicus, in the ascending order, for 4 groups in total. The period of the specific mating calls confirmed by the study is a period in which the frequency of calls was the highest among the periods when the specific calls were detected. Since it is associated with the known mating period of each species, the period of the high frequency of calls confirmed by the bioacoustic monitoring can be regarded as the mating season. This study is meaningful in that it is the early research that has used the bioacoustic recording technology to identify species and ecological characteristics of species of nocturnal birds in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.284-293
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• 2020

Rice consumption in Korea has been decreasing as the eating habits of the Korean people have diversified with rapid economic growth. Recently, floury endosperm rice cultivars were developed to boost rice consumption and replace wheat flour consumption with rice flour, which is vulnerable to viviparity under wet weather during the grain-filling stage because of its loosely packed starch granule structures. To overcome this limitation, it is necessary to find a suitable rice transplanting date to produce high-quality rice flour by altering the heading ecology type and changing the cultivation time by region. We examined four floury endosperm rice cultivars (FERC) in the Cheongju (central plain area) and Boeun (mid-mountainous area) regions of Korea from 2017 to 2019. Of the FERCs, the mid-late maturing types (MMT) Seolgaeng (SG), Hangaru (HGR), and Shingil (SGL) exhibited high yield and yield components after transplanting May 30 in both regions; the early maturing type (EMT) Garumi 2 (GRM2) also exhibited high yield after transplanting June 20 in Cheongju. In addition, MMTs showed the same tendency as the characteristics shown in Cheongju when grown in the Boeun region, and EMT displayed high yield and yield components after transplanting June 10. The FERCs could easily present pre-harvest sprouting in the rainy season during the grain-filling stage after 20 days post-heading because the mean temperature and frequency of more three-day rainfalls have increased over the last 5 years from the previous annual averages. Viviparity of HGR and GRM2 decreased as the transplanting date was delayed, with decreases of 2.3%-4.6% in HGR and 11.9%-23.1% in GRM2 according to the region. SGL was generally resistant to viviparity because of the Tongil type. To minimize pre-harvest sprouting and produce high yield of rice flour in the Chungbuk province, the most suitable transplanting time was the end of May in MMT and the middle and end of June in EMT.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.289-300
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• 2009

Flora distribution was surveyed in the newly reclaimed tidal flats in the west coastal area in Korea to understand changes in flora dynamics after reclamation. The surveyed reclaimed tidal flats were the newly reclaimed tidal flat in Hangdam, the mid Kyonggi Bay in 2002, and three reclaimed lands in Seukmun and Daeho, Chungnam, and Hangdam in Kyonggi Bay, of which reclamation years based on embankment were 7, 9 and 18 years, respectively. In the newly reclaimed tidal flat, the dominant flora was Suaeda japonica and other florae were rare, while various halophytes and glycophytes were distributed in the reclaimed lands. On the newly reclaimed tidal flat, four species of halophytic pioneer florae, Salicornia europaea, Suaeda glauca, Suaeda japonica, and Suaeda maritime occurred, and along with age facultative halophyte and glycophyte occurred sequently. On the reclaimed lands, the florae were more complex with various facultative halophyte and glycophyte, so these were predominated rather than pioneer halophyte, while one of pioneer halophyte that Suaeda japonica was not occurred. Increasing of various facultative halophyte and glycophyte, and decreasing of pioneer halophyte indicated that flora changed toward to increase of facultative halophyte and glycophyte by aged after reclamation. On the newly reclaimed tidal flat the ratio of flora species changed rapidly with the invasion of plant. This implied that the flora had begun to change in the early stage of reclamation. Facultative halophyte and glycophyte started to increase on the early stage of reclamation but relative density and frequency of pioneer halophyte was higher than facultative halophyte and glycophyte. According to the investigation up to 3 years after reclamation, pioneer halophyte predominated on it. Although flora changed, there were common representative halophytes among the reclaimed tidal flats: Salicornia europaea, Suaeda maritima, and Suaeda glauca as pioneer halophyte, Aster tripolium, Sonchus brachyotus, and Phragmites communis as facultative halophytes.

• Journal of the Korean earth science society
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• v.38 no.3
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• pp.194-208
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• 2017

This study analyzed the correlation between tropical cyclone (TC) frequency and the western North Pacific monsoon index (WNPMI), which have both been influential in East China Sea during the summer season over the past 37 years (1977-2013). A high positive correlation was found between these two variables, but it did not change even if El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) years were excluded. To determine the cause of this positive correlation, the highest (positive WNPMI phase) and lowest WNPMIs (negative WNPMI phase) during an eleven-year period were selected to analyze the mean difference between them, excluding ENSO years. In the positive WNPMI phase, TCs were mainly generated in the eastern seas of the tropical and subtropical western North Pacific, passing through the East China Sea and moving northward toward Korea and Japan. In the negative phase, TCs were mainly generated in the western seas of the tropical and subtropical western North Pacific, passing through the South China Sea and moving westward toward China's southern regions. Therefore, TC intensity in the positive phase was stronger due to the acquisition of sufficient energy from the sea while moving a long distance up to East Asia's mid-latitude. Additionally, TCs occurred more in the positive phase. Regarding the difference in 850 hPa and 500 hPa stream flows between the two phases, anomalous cyclones were strengthened in the tropical and subtropical western North Pacific, whereas anomalous anticyclones were strengthened in East Asia's mid-latitude regions. Due to these two anomalous pressure systems, anomalous southeasterlies developed in East China Sea, which played a role in the anomalous steering flows that moved TCs into this region. Furthermore, due to the anomalous cyclones that developed in the tropical and subtropical western North Pacific, more TCs could be generated in the positive phase.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.318-326
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• 2011

The population ecological characteristics of the Crucian carp, Carassius auratus, were determined in order to estimate stock of the mid-upper system of the Seomjin River. The fish ranged in size from 95 to 288mm total length. The age was determined by counting the scale annulus. The scales displayed clear annulus that were used to estimate the age. The oldest fish observed in this study was 5 years old. Age-2 fishes were the most numerous in the sample(n=38), followed in frequency be age-3(n=22). Marginal index analysis validated the formation of a single annulus per year. The relationship between body length and body weight was BW = $0.0038BL^{3.73}$($R^2$=0.96) (p<0.01). The relationship between the scale radius and body length was BL = 2.362R+2.76($R^2$=0.89). The von Bertalanffy growth parameters estimated from a non-linear regression method were $L_{\infty}$=33.2 cm, $W_{\infty}$=1,798.4 g, $K=0.20year^{-1}$ and $t_0$=-0.51year. Therefore, Growth in length of the fish was expressed by the von Bertalanffy's growth equation as $L_t=33.23$($1-e^{-0.20(t+0.51)}$)($R^2$=0.98). The annual survival rate was estimated to be 0.427year$^{-1}$. The instantaneous coefficient of natural mortality of estimated from the Zhang and Megrey method was $0.784year^{-1}$, and instantaneous coefficient of fishing mortality was calculated $0.067year^{-1}$. From the estimates of survival rate, the instantaneous coefficient of total mortality was estimated to be $0.851year^{-1}$.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.20-28
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• 1999

To improve Bacillus strains producing biopolymer, conditions for protoplast formation and regeneration were investigated in biopolymer producing Bacillus subtilis K-1 and lactose utilizing Bacillus coagulans. Bacillus subtilis K-1 mutant (SM-2) and Bacillus coagulans mutants (CM-12) were marked auxotrophic and antibiotics-resistant (SM-2) and an antibiotics-resistant mutants, respectively. To formate protoplasts derived from the mutants, conditions were established as follows. For B. subtilis mutant SM-2, its culture in mid-logarithmic phase was added with penicillin G (1.0 unit/ml) and further reacted for 1.5 hr. Cells were collected and then treated in lysis fluid (pH 7.0) containing 0.4 M sucrose and lysozyme $25\;{\mu}g/ml$ for 40 min at $37^{\circ}$. Protoplast formation was very successful (99.6%) and the ratio of cell wall regeneration was 2.4%. For Bacillus coagulans mutant CM-12, its mid-logarithmic phase culture was treated with penicillin G (0.3 unit/ml) and glycine (0.5%) for 1hr. Cells were collected and then resuspended in lysis buffer (pH 7.0) containing 0.6 M lactose and lysozyme $(300\;{\mu}g/ml)$ for 30 min at $37^{\circ}$. Protoplast formation was also successful (90.8%) and cell wall regeneration ratio was similar to SM-2 (2.2%). To improve regeneration frequency, regeneration medium was obtained as followed condition,. Cell wall regeneration was improved 2-4 folds with 5.1% for B. subtilis SM-2 and 10.3% for B. coagulans CM-12 when protoplasts mixed with soft top agar(0.4%) was overlaid onto trypticase soy broth medium containing 0.4 M sucrose, 0.7% casamino acid, 1% PVP, 25 mM $MgCl_2,\;25\;mM\;CaCl_₂$ and 1.5% agar.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.2
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• pp.1-15
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• 2016

This study aims at the consideration of the usages of traditional waterscape elements, which are difficult to define their concepts and their differences and it has been proceeded mainly with analysis of literature. It elicited various waterscape types by extracting the place names associated with the watersacpe elements from the chapter "Sancheon" of the volumes Gyeongsang-province in "Sinjeung Donggukyeojiseungram", which is a government-compiled geography book in the early period of Joseon Dynasty, and drew the features of each waterscape element by interpreting the dictionary definition and the original text and studying the similar examples. The results of study are drawn as follows. 1. The chapter "Sancheon" includes 22 types of waterscape elements and they are classified by means of locations and water-flow forms: River Landscape, Lake & Pond Landscape, Coast landscape. 2. River landscape maintaining constant natural water-flow constitutes the linear type, related to the class of stream, which includes 'Su(water)', 'Gang(river)', 'Cheon(stream)' and 'Gye(brook)' and the dotty type, created by the nature of trenched meander rivers, which includes 'Tan(beach)', 'Roe(rapids)', 'Pok(waterfall)' and 'Jeo(sandbank)'. 3. Lake & Pond Landscape forming water collected in a certain area constitutes 'Ho(lake)', which is a broad and calm spot created around mid and down stream of river, 'Yeon(pool)', 'Dam(pond)', 'Chu(small pond)', which are naturally created on the water path around mid and down stream of river, 'Ji(pond)', 'Dang(pond)', 'Taek(swamp)', which is collected on a flatland and 'Cheon(spring)', 'Jeong(spring)' which means gushing out naturally. 4. Coast Landscape includes 'Ryang', 'Hang', which are the space between land and an island or islands, 'Got(headland)' which sticks out from the coast into the sea, 'Jeong(sandbank)' which forms sandy beaches and 'Do' which shows high appearance frequency by reflecting the geographical importance of islands. This study comprehended the diversity of traditional waterscape elements and drew the fact that they are the concept reflecting the differentiated locational, scenic and functional features. That way, it understood the aesthetic sense on nature, which ancestors had formed with the interests in natural landscape and the keen observation on it, became the basic idea elucidating the characteristic on Korean traditional gardens, which minimize the artificiality and make nature the subject.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.387-401
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• 2021

Thrips infesting hot peppers were monitored in greenhouses using yellow sticky traps. In addition, the hot peppers infected with tomato spotted wilt virus (TSWV) were observed during the monitoring period. The flower thrips (Frankliniella intonsa) were initially trapped at a low density just after transplanting seedlings of hot peppers at late March. The western flower thrips (Frankliniella occidentalis) were trapped after mid April. These two thrips represented more than 98% of the total thrips attracted to the traps after May, in which F. intonsa showed higher occurrence frequency than F. occidentalis. The total number of thrips had two peaks at mid May with a small and short-term peak and at June-July with a large and long-term peak. The trapped thrips exhibited inconsistent sex ratios, suggesting a seasonal parthenogenesis. Different geographical populations were varied in cytochrome oxidase I sequences, in which local populations in Andong shared a high sequence similarity. TSWV-infected hot peppers, which might be mediated by these two thrips species, were observed and confirmed by an immunoassay kit and a molecular diagnosis using RT-PCR. In addition, the TSWV was detected in F. occidentalis collected from the infected hot peppers. Three open reading frames (NS_S, N, and NS_M) of the isolated TSWV genomes were sequenced and showed multiple point mutations containing missense mutations among geographical variants. When the isolated TSWV was fed to nonvirulent thrips of F. occidentalis, the virus was detected in both larvae and adults. However, the viral replication occurred in larvae, but not in adults.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.101-114
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• 2019

In this study, we carry out the numerical simulation to trace the yearly shoreline change of Mang-Bang beach, which is suffering from erosion problem. We obtain the basic equation (One Line Model for shoreline) for the numerical simulation by assuming that the amount of shoreline retreat or advance is balanced by the net influx of longshore and cross-shore sediment into the unit discretized shoreline segment. In doing so, the energy flux model for the longshore sediment transport rate is also evoked. For the case of cross sediment transport, the modified Bailard's model (1981) by Cho and Kim (2019) is utilized. At each time step of the numerical simulation, we adjust a closure depth according to pertinent wave conditions based on the Hallermeier's analytical model (1978) having its roots on the Shield's parameter. Numerical results show that from 2017.4.26 to 2017.10.15 during which swells are prevailing, a shoreline advances due to the sustained supply of cross-shore sediment. It is also shown that a shoreline temporarily retreats due to the erosion by the yearly highest waves sequentially occurring from mid-October to the end of October, and is followed by gradual recovery of shoreline as high waves subdue and swells prevail. It is worth mentioning that great yearly circulation of shoreline completes when a shoreline retreats due to the erosion by the higher waves occurring from mid-March to the end of March. The great yearly circulation of shoreline mentioned above can also be found in the measured locations of shoreline on 2017.4.5, 2017.9.7, 2017.11.7, 2018.3.14. However, numerically simulated amount of shoreline retreat or advance is more significant than the physically measured one, and it should be noted that these discrepancies become more substantial for the case of RUN II where a closure depth is sustained to be as in the most morphology models like the Genesis (Hanson and Kraus, 1989).

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.173-187
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• 2023

The forest protection policies implemented in South Korea have resulted in the significant accumulation of forest. Moreover, the associated public interest has also been closely evaluated. As forests mature, there arises a need for forest management (FM) practices, such as thinning and harvesting. It is therefore essential to perform a scientific analysis of the long-term effects of FM. In this study, conducted in Mt. Gariwang, the effect of FM on forest succession and wood production (WP) were evaluated based on changes in aboveground biomass (AGB) using the LANDIS-II model. The FM consists of three scenarios (Selection, Shelterwood, and Two-stories), characterized based on the harvest intensity, frequency, and period. The model was applied to changes in the forest over 200 years. All scenarios show that the total AGB decreased immediately after thinning and harvesting. However, AGB recovery time differed among scenarios, with recovery to preharvest level occurring from 15 to 50 years after harvest; further, after 200 years, harvested forests had a greater total AGB than forests without FMs In particular, the changes in AGB of each species was different depending on its shade tolerance. The AGB of currently dominant shade-intolerant and mid-tolerant species decreased dramatically after harvesting. However, shade-tolerant species, dominant in the understory, continued to grow but were not harvested due to their small size. The cumulative WP for each scenario was estimated at 545.6, 141.6, and 299.9 tons/ha in Selection, Shelterwood, and Two-stories, respectively. The composition of WP differed according to harvest intensity and period. Most WP originated from shade-intolerant and mid-tolerant species in the early period. Later, most WP was from shade-tolerant species, which became dominant. The modeling approach used in this study is capable of analyzing the long-term effects of FM on changes in forests and WP. This study can contribute to decision making to guide FM methods for a variety of purposes, including WP and controlling forest composition and structure.