• Title/Summary/Keyword: dominant period

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Study on Competition Ecology of a Perennial Weed Sagittaria pygmaea Miquel in Paddy Field (논 다년생잡초(多年生雜草) 올미의 경합생태(競合生態)에 관한 연구(硏究))

  • Lee, H.K.;Guh, J.O.
    • Korean Journal of Weed Science
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    • v.2 no.2
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    • pp.114-121
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    • 1982
  • Sagittaria pygmaea Miquel is widely infested and is the most dominant perennial weed in paddy field in Korea. This study was carried out in order to clarify the factors influencing tuber production and the competition ecology. The tuberization capacity in the paddy field transplanted with the small seedlings of rice was higher than in the paddy field transplanted with the vigor seedlings of rice. The stage which rice plants were most damaged by S. pygmaea plants was the period from 31 to 37 days after transplanting. According to the increasing of Eleocharis acicularis Roem. in the condition of rice cultivation, the number of S. pygmaea plants was remarkably reduced. Small size tubers planted within deep soil produced less tubers than large size tubers did. The number of plants and tubers were remarkably increased under the high levels of fertilization. Phosphorus was essential as well as nitrogen for tuberization. And the tuberization capapcity was different with the organic matter content in soil and with the soil moisture.

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Study on the Long-term Changes in Water Quality and Benthic Ecology and Evaluation on Effect of the Barrage in Nakdong River Estuary (낙동강 하구 수질 및 저서 생태의 장기 변화와 하굿둑의 영향 평가)

  • Park, Sohyun;Lee, Jiyoung;Choi, Jae Ung;Heo, Nakwon;An, Soonmo
    • Journal of Wetlands Research
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    • v.18 no.1
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    • pp.58-67
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    • 2016
  • This study was performed to investigate the long-term changes in water quality and benthic ecology around the Nakdong River Estuary. The effect of the estuarine barrage on the ecosystem was also evaluated. The water quality was interpreted using the field survey (2013 and 2014) and monitoring data (MOE, 1989~2013) and the macrobenthic-fauna was investigated through analysis of the field survey data (2014) and literatures review (1985~2013). The long-term variation of water quality of Nakdong River generally showed increased nutrient concentration with decreased discharge, while abrupt influence of the barrage construction was not observed. However, the nutrient and organic matter concentration inside the barrage distinctly was higher than the concentration outside the barrage because the mixing of fresh and seawater was limited by the barrage. Especially, in the period of low discharge during winter, the Chlorophyll-a concentration clearly increased more in the downstream inside the barrage, showing the barrage effect. In other words, stagnant effect caused by barrage construction had an effect on the water quality degradation in dry seasons. As for the benthic ecology inside barrage after barrage construction, molluscans and brackish-water crustaceans disappeared. Outside the barrage, benthic ecosystem has deteriorated and the small-sized organic indicative species like Prionospio membranacea, Pseudopolydora kempi, Sinocorophium sinensis became dominant due to several construction such as Myeong-Gi Bridge, Airport construction, industrial complex after the Nakdong barrage construction.

Colonial Tourism and Modernism in Korean Modern Architecture - Focused on Railroad Station during Japanese Ruling Era - (한국근대건축에서 식민지관광주의와 모더니즘에 관한 연구 - 일제강점기 철도역사 건축을 중심으로 -)

  • Ahn, Chang-Mo
    • Journal of architectural history
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    • v.11 no.2 s.30
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    • pp.7-22
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    • 2002
  • Architectural style is said to be product reflecting political, social and cultural condition. Especially, in colony, architectural style is strongly related to political condition or policy. After colonization in 1910, public buildings with western historical architectural style in Japanese version were widely built by Japanese colonial government in Korea. And in the late 1920s, modernism style in architecture became dominant in Korea as like other countries. In this situation, curious buildings in strange architectural styles came out. One example is railroad station buildings with traditional Korean architectural style and timber house station having a steep roof which is widely used in North Europe such as Alps area with good sights and mountains. Generally, the colonizer says that colonization is the only way to save the colony at crisis defined by colonizer and they insist that they can help the colony modernize. To justify colonization, the colonizer attributes the colonization to the characteristics of the nation and stagnation of the traditional culture etc.. Accordingly, the colonizer tries to depreciate colony's traditional value and culture. In case of colony which has similar cultural background historically (in this case, economical exploitation is less important than other Asian colony by European power), this depreciation of traditional value and culture in Korea was done more strongly than others. At this time, we should understand special relation between Korea and Japan historically. Even though, colony's locality is adopted by the colonizer in public fields, which is based on political purpose or exotic taste etc.. In early days of Japanese ruling period, Japan never use the Korean traditional facts in public. Therefore there is no use of Korean traditional architectural style in public field. In late 1920s, some railroad station buildings were constructed in new styles without precedence in modern Korea. One is railroad station buildings in Korean traditional architectural style, the other is railroad station buildings in timber house stations having a steep roof which is different form western historical architectural style. It was mystery that Japan had constructed railroad stations in Korean traditional style which Japan had tried to destroy together with Western style railroad station buildings. This paper is made to solve the mystery why the colonizer(Japan) constructed entirely different types of railroad stations at the same time in the late 1920s and 1930s. The key point to solve this mystery is tourism. In this paper, to solve this mystery, I try to use terminology' 'Colonial Tourism' in architecture why colonial power had constructed railroad stations with colony's traditional architectural style and Western style having a steep roof which can be seen north European region.

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Monitoring Vegetation Changes after Constructing the Vegetation-mat Measures for Greening in Embankment - A Case Study of Tancheon, Seongnam - (호안 녹화용 매트 시공 후 식생변화 모니터링 - 성남시 탄천을 중심으로 -)

  • Lee, Soo-Dong;Kang, Hyun-Kyung;Jang, Han-Sol
    • Korean Journal of Environment and Ecology
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    • v.24 no.3
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    • pp.302-317
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    • 2010
  • In this study, not only to present the management plan but also to verify the effectiveness for a area of improving the landscape and the area of creating the base of bio-inhabitation in Tancheon stream concrete embankment where were practised the vegetation-mat measures for greening via monitoring i.e. restoration progress. The results of monitoring, there were a total of 41 taxa, 18 families, 38 species, 3 varieties in 2006, moreover in the 2007, there were a total of 59 taxa, 19 families, 56 species, 3 varieties and in the period 2008, 64 taxa, 29 families, 59 species, 8 varieties. Therefore, these site has increased the plant spaces year by year. The distribution of vegetation characteristics shows that Miscanthus sacchariflorus and Pennisetum alopecuroides expands their influence in the area of applying the construction method. Those area appears a diversity of native species by the stream deposition at the flood. Thus, its condition is very soundly ecological health and eco-friend. At present, native species have been dominant, however, disturbed species and invasive species can be expected to increase dramatically in the future. Therefore, it is necessary to a long-range monitoring and management for maintaining an environmentally sound aquatic ecosystem. On this area refer to mix the river vegetation of primary succession and disturbed vegetation. For that reason, the method of constructing the vegetation-mat measures for greening in embankment does not need to remove the concrete and can install a coir-mat on the top. It leads to improve the landscape, moreover, it was analysed the such dramatic changes in the vegetation species richness by providing continuous the plant growth basis have a impact on in bio-diversity.

The Characteristics of the Fish Community in Yeongwol Hanbando Wetland (영월한반도습지의 어류군집 특성)

  • Han, Sang-Jin;Lee, Kwang-Yeol;Yoon, Young-Jin;Choi, Jae-Yoon;Kim, Joon Chul;Choi, Jae-Seok
    • Korean Journal of Environment and Ecology
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    • v.28 no.4
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    • pp.424-431
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    • 2014
  • Analysis of the fish community in Yeongwol Hanbando wetland in Korea was investigated from April to October 2012. During the survey period, total 33 species belonged to 10 families and 7,107 individuals. There were 18 Korean endemic species (52.94 %), including to Acheilognathus signifer. Also, the dominant species were Zacco koreanus at St. 1, 2, 3 & 5, as well Acheilognathus signifer at St. 6, and Pseudopungtungia tenuicorpus at St. 7, respectively, and these species were inhabited in the midstream. But at St. 4, Carassius auratus was dominance, so there appeared to characteristics of downstream or lentic habitat. Also, according to the similarity analysis on fish species and their individuals in each sites, they were divided into three major groups (A,B and C). Among them, group C (St. 4) showed the special inverse characteristics as a stagnant pond. unlike the river branch (group A) and anthropogenic disturbances receiving stream point (group B), Therefore, the ecosystem of Yeongwol Hanbando wetland is considered to very unique and these characteristics are not found in other stream ecosystems and it is confidently believed that the ecological value is very high.

The Ichthyofauna and Community Structure of Fish at Wondong Marsh in the Kyeongnam Province, Korea (원동습지의 어류상과 군집구조)

  • Yang, Hong-Jun;Kum, Ji-Don;Lee, Yong-Ho
    • Korean Journal of Ichthyology
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    • v.13 no.4
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    • pp.261-266
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    • 2001
  • The ichthyofauna and the structure of fish community were surveyed from June to August in 2000 at four stations of the Wondong marsh, Yangsan city in Kyungnam province. During the study period, 24 species belonging to eight families were collected. Cyprinid fish occupied 62.5% (15 species) and cobitid and centrarchid fish 8.3% (each 2 species). According to relative abundance in the whole marsh, Z. platypus (23.2%) was dominant species and S. gracilis majimae (14.2%) was subdominant species. M. salmoides (9.6%), C. auratus (8.3%), P. herzi (8.3%), M. yaluensis (6.5%), M. anguillicaudatus (4.0%), L. macrochirus (3.4%), P. parva (2.8%), R. ocellatus (2.5%), C. brevicauda (2.5%), C. sinensis (2.5%) and O. platycephala (2.2%) were common species and C. carpio, A. rhombeus, H. labeo, S. variegatus wakiyae, S. chankaensis tsuchigae, Z. temmincki, O. bidens, S. asotus, C. herzi, R. brunneus, C. argus were rare specieswhich occupied less than 2.0% in relative abundance. Six species of S. variegatus wakiyae, S. chankaensis tsuchigae, S. gracilis majimae, M. yaluensis, C. herzi and O. platycephala in observed species were known as endemic species. By analyzing of fish community in the surveyed area, the species diversity and evenness of the fishes were high but dominance was low. And the similarity of the fish species among the sites was mid-grade as more than 0.55 in index.

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Depth-dependent Variability of Fish Fauna in the Coastal Waters off Hupo, East Sea (동해 후포 연안 어류상의 수심별 차이)

  • Lee, Chung Il;Jung, Hea Kun;Kwon, Soon Man;Han, Moon Hee;Seol, Kang Su;Park, Joo Myun
    • Korean Journal of Ichthyology
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    • v.30 no.1
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    • pp.36-45
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    • 2018
  • The temporal and depth-related variations in the species composition and abundance of demersal fish assemblage were studied in the coastal waters off Hupo, East Sea. Fish samples were collected seasonally between 2011 and 2017 at two stations of study area using trammel net and bottom gill net. In total, 46 fish species belonging to 17 families were collected during study period, with 36 and 22 species occurring in depths of ~80 m (site A) and ~140 m (site B), respectively. Glyptocephalus stelleri, Cleisthenes pinetorum and Gymnocanthus herzensteini were abundant at shallower site, and Dasycottus setiger at deeper site. The number of species, abundance, biomass and diversity fluctuated with water depth, but not temporally (both seasonally and annually). Analysis of similarity (ANOSIM) revealed that the fish assemblage structures were significantly different with water depth, but not by year or season. Non-metric multidimensional scaling (MDS) ordination plot emphasized visually in spatial difference of fish assemblages, and it was due to differential contributions of dominant species in relation to water depth and temperature.

Deposition Characteristics of Water-soluble Inorganic Ions in the Iksan Ambient Air during Fall, 2004 (가을철 대기환경 중 수용성 이온성분의 침적특성)

  • Kang, Gong-Unn;Kim, Nam-Song;Jeon, Seon-Bok
    • Journal of Environmental Health Sciences
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    • v.32 no.4 s.91
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    • pp.359-372
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    • 2006
  • In order to investigate the daily deposition characteristics of water-soluble inorganic components in airborne deposit on the Iksan, deposition samples were collected using a deposition gauge from October 16 to November 1, 2004. Deposition samples were collected using two different sampling gauges, a dry gauge and a wet gauge, respectively. To get wet the bottom of wet gauge during the sampling period, the volume of $30{\sim}50ml$ distilled ionized water was added in a wet gauge before the beginning of each deposition sampling. Deposition samples were collected twice a day and analyzed for inorganic water-soluble anions ($Cl^-,\;{NO_3}^-,\;{SO_4}^{2-}$) and cations (${NH_4}^+,\;Na^+,\;K^+,\;Mg^{2+},\;Ca^{2+}$) using ion chromatography. Qualify control and quality assurance of analytical data were checked by the data obtained from reinjection of standard solution, Dionex cross check standard solutions, and random several deposition samples, and measured data was estimated to be reliable. Considering the deposition sample volume, the sampling time, the surface area of sampling container, and the ion concentration measured, the daily deposition amounts for measured ions were calculated in $mg/m^2$. The total daily deposition amounts of all measured ions for dry and wet gauge were $7.5{\pm}2.8$ and $17.7{\pm}4.2mg/m^2$, respectively. A significant increase in deposition amount during rainfall days was observed for both wet gauge and dry gauge, having no difference of deposition amount between in wet gauge and in dry gauge. The mean deposition of all ions measured in this study were higher in wet gauge than in dry gauge because of the surface difference of the sampling container, especially for ${NH_4}^+\;and\;{SO_4}^{2-}$. The mean deposition amounts of ${NH_4}^+\;and\;{SO_4}^{2-}$ in wet gauge were found to be about 10 times and 3 times higher than those in dry gauge, while the rest of the chemical species were equal or a little higher in wet gauge than in dry gauge. Dominant species in dry gauge were ${NO_3}^-\;and\;Ca^{2+}$, accounting for 21% and 28% of the total ion deposition, whereas those in wet gauge were ${SO_4}^{2-}\;and\;{NH_4}^+$, accounting for 19% and 41% of the total ion deposition, respectively.

Characteristics of Meteorological Conditions and Air Pollution in a Valley City on Bad Visibility Days of the Cold Half Year (한후기 계곡지형 내 도시 시정악화 발생일의 기상 및 대기오염 특성 분석)

  • Kang, Jae-Eun;Song, Sang-Keun;Kim, Yoo-Keun
    • Journal of Environmental Science International
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    • v.22 no.6
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    • pp.745-759
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    • 2013
  • The characteristics of meteorological conditions and air pollution were investigated in a valley city (Yangsan) on bad visibility days (from 05:00 to 09:00 LST) of the cold half year (November 2008 to April 2009). This analysis was performed using the hourly observed data of meteorological variables (temperature, wind speed and direction, relative humidity, and 2 m and 10 m temperature) and air pollutants ($NO_2$, $SO_2$, $PM_{10}$, and $O_3$). In addition, visibility data based on visual measurements and a visibility meter were used. The bad visibility days were classified into four types: fog, mist, haze, and the mixture (mist+haze). The results showed that the bad visibility days of the four types in the valley city were observed to be more frequently (about 50% of the total study period (99 days except for missing data)) than (27%) those near coastal metropolitan city (Busan). The misty days (39%) in the valley city were the most dominant followed by the hazy (37%), mixture (14%), and foggy days (10%). The visibility degradation on the misty days in Yangsan was closely related to the combined effect of high-level relative humidity due to the accumulation of water vapor from various sources (e.g. river, stream, and vegetation) and strong inversion due to the development of surface radiative cooling within the valley. On the hazy days, the visibility was mainly reduced by the increase in air pollutant (except for $O_3$) concentrations from the dense emission sources under local conditions of weaker winds from the day before and stronger inversion than the misty days. The concentrations of $NO_2$, $PM_{10}$, and $SO_2$ (up to +36 ppb, $+25{\mu}g/m^3$, and +7 ppb) on the hazy days were a factor of 1.4-2.3 higher than those (+25 ppb, $+14{\mu}g/m^3$, and +3 ppb) on the misty days.

Functions and Roles of Digital Landscape Architectural Drawing (조경 설계에서 디지털 드로잉의 기능과 역할)

  • Lee, Myeong-Jun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.46 no.2
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    • pp.1-13
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    • 2018
  • This work discusses the major roles of digital technologies in the history of landscape architectural drawing, and offers a critique of the dominant trend towards realism in recent digital landscape representations. During the period of transition from conventional drawing tools, computer technologies generally functioned as mechanical tools to imitate prior manual techniques. Specifically, the GIS was served as a mechanical tool to efficiently process the manual layer cake; CAD software generally functioned to translate physical models to two-dimensional construction documents while graphic software generally functioned as a tool to perform processes similar to those of manual collage and montage techniques. Recent digital landscape drawings tend to adopt a realistic depiction like the painting of landscape appearance. In the representations, discernible traces of cutting and assembling are removed via graphic software; thus, the complete representations are perceived as if they were a copy of an actual landscape. The realistic images are an easy way to communicate with the public. However, it is difficult to achieve a full embodiment of all of the multisensory characteristics of a landscape through these visuals. They often deceive viewers by visualizing idealized conditions of not-yet-actualized landscapes and production of the final images takes up a large portion of the overall design process. Alternatively, 3D digital modeling of landscape performance and creative uses of digital technologies during the overall design process, as well as hybridized techniques with different drawing techniques and technologies, provide the opportunity to explore various aspects of a landscape.