• The Korean Journal of Ecology
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• v.28 no.1
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• pp.45-53
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• 2005

Urban stream is an important place supporting urban ecosystem. This study was carried out to clarify the role of Jungrangchun for wintering waterbirds in Seoul. We monitored the fluctuation of waterbirds population using our census data (1997/98 winter) and pervious census data (the Ministry of Environment and National Institute of Environmental Research $1999{\sim}2004$). Wintering behaviours of common teals (Anas crecca) were also observed to understand the habitat use of waterbirds in this area. As a result of this, Jungrangchun was an important place to support $3,004\sim8,237$ wintering birds, mainly dabbling ducks and diving ducks. The population of diving ducks showed high annual fluctuation whilst the population of dabbling ducks regularly used this area every year The maximum number of waterbirds foraged and rested in late January and late February. In daily use, the number of waterbirds increased on afternoon and rapidly increased after sunset. It is assumed that waterbirds used this area not only as a nocturnal feeding site but also daytime feeding site. Thus, this result suggest that Jungrangchun is important for not only the daily use but also the nocturnal use of wintering waterbirds. The number of diving ducks was increased with low temperature and high wind speed. Therefore, this area was also a shelter of diving ducks on chilly and windy day.

• Journal of KIISE:Software and Applications
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• v.28 no.1
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• pp.26-30
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• 2001

Multipopulation Genetic Algorithm(MPGA) is the modified form of Genetic Algorithm(GA), which was devised for covering for overing the defect of general GA. The core of MPGA is said to be the migration method. The fitness-based migration method and the random migration method are currently used. The random migration method is more general than the other because it keeps the diversity of the population. In this paper, a new migration method is suggested. This method has a merit that it can improve the speed of conergence, compared to the general migration method. This method is compared with the general migration method.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.9-14
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• 1998

Air current speeds were controlled of 0.3, 0.5, 0.7 and 0.9 m.s$^{-1}$ to investigate the effects of air current speeds on the growth of eggplant plug seedlings (Solanum melongena L.) in a wind tunnel under artificial lighting. Growth of plug seedlings was influenced by the magnitude of air current speed and the traveling distance of regulated air flow. Stem length. ratio of length to diameter in stem, plant height .and number of leaves of plug seedlings decreased with the increasing air current speed and were significantly different at 5% level. Net photosynthetic rates of plug stand increased with the increasing air current speed and took a maximum value at the air current speed of 0.7~09 m.s$^{-1}$ . Stem diameter decreased and leaf area increased with the traveling distance of regulated air flow. Fresh weight and T/R ratio of dried weight were not influenced by the air current speed. Optimum control for microclimates inside the plug stand is needed to produce the uniform growth and high quality of plug seedlings in a semi-closed plant Production system under artificial lighting.

• Korean journal of applied entomology
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• v.28 no.2
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• pp.61-68
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• 1989

To investigate the possibility of the BPH control by systematic application of insecticides, biological effects of buprofezin and isoprothiolane upon the BPH population was evaluated in the laboratory and pot. Both chemicals did not affect the developmental period of the nymphal stage with the applied dosages. When the buprofezin treated instar nymph was developed to the adult, adult's longevity was fairly reduced and such an effect of buprofezin was greater upon the younger instar nymphs. Residual effect of buprofezin was about 30 days in the pot. And it could suppress the BPH population when the younger instar nymphs were dominant age group in the population at the time of treatment. Isoprothiolane was also more effective for the suppression of the BPH population when the younger instar nymphs were dominant at the time of treatment. And it was expected that by buprofezin treatment in July the control effect of isoprothiolane against the BPH population could be maximized when it was treated to control the rice neck blast in late July or early August, because buprofezin could induce the biased population age distribution in which younger instar nymphs were main group at the time of isoprothiolane treatment.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.5-5
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• 2010

제주지역에 분포하는 특산식물의 현황을 알아보기 위해 지난 2007년부터 2010년까지 현지조사를 실시하여 44과 75속 63종 17변종 13품종으로 총 93분류군에 대한 자생지 환경, 개체군 동태, 생육특성 및 위협요인 등에 대한 자료를 구축하였다. 이중 세계적으로 제주지역에만 분포하는 제주특산식물은 긴다람쥐꼬리(Huperzi integrifolium) 등 27과 46속 36종 12변종 8품종으로 총 56분류군으로 분석되었으며, 제주도를 포함하여 우리나라에만 분포하는 한국특산식물은 구상나무(Abies koreana) 등 20과 28속 24종 4변종 4품종으로 총 32분류군인 것으로 파악되었다. 그리고 조사대상 특산식물 중 바위좀고사리(Asplenium sarelii var. anogrammoides) 등 5분류군은 분류학적 검토와 함께 특산식물여부에 대한 검토가 필요한 것으로 판단되었다. 그리고 개나리(Forsythia koreana)는 조경용으로 식재된 종이므로 제주지역에 자생지가 확인된 특산식물은 39과 70속 59종 16변종 12품종으로 총 87분류군으로 볼 수 있다. 제주지역의 특산식물은 해안지대에서 확인된 갯겨이삭(Puccinellia coreensis)부터 한라산 정상에서 자라는 한라솜다리(Leontopodium hallaisanense)까지 제주도 전역 분포하고 있으나 종에 따라 서로 다른 분포특성을 보였다. 특히, 한라산 해발 1,400m 이상 아고산대에 집중 분포하는 특성을 보였다. 특산식물의 자생지내 개체군의 동태를 보면 대부분의 식물이 개체수 및 분포범위가 한정되어 있는 것으로 나타났다. 더욱이 지리산오갈피(Eleutherococcus divaricatus var. chiisanensis)는 2개체만이 확인되어 종보전이 시급한 것으로 조사되었고, 한라솜다리, 모데미풀(Megaleranthis saniculifolia), 한라각시둥굴레(Polygonatum humile var. humillimum) 등 상당수의 식물 종이 수십 개체 이내로 매우 적은 개체수를 유지하고 있었다. 제주지역에 분포하는 특산식물은 인위적 또는 자연적 요인으로 인해 많은 자생지 면적감소나 개체수 감소 등의 위협요인을 갖고 있는 것으로 나타났다. 특히, 중산간 이하에 자라는 특산식물은 접근성 등이 용이하여 도채 등의 위험성이 높은 것으로 판단된다. 그리고 한라산국립공원 내에 분포하는 특산식물은 인위적 훼손 위험성은 상대적으로 낮은 편이나 자연적 요인 즉, 식생변화 등으로 인해 자생지 및 개체수 감소가 이루어질 것으로 보여 체계적인 종 보존전략이 마련되어야 할 것으로 판단된다. 한편, 제주지역 특산식물 중 자생지가 확인된 식물 종을 대상으로 근연종 분석 등을 통해 유용성을 분석하면 식물체 일부가 약용으로 가능한 식물 종이 개족도리(Asarum maculatum) 등 전체의 67.1%를 차지하였고, 관상용으로 활용가치가 높은 식물 종은 구상나무(Abies koreana) 등 전체의 60.2%인 것으로 분석되었으나 대부분의 종이 희소성의 가치가 있어 모든 특산식물이 관상용으로 이용가치가 있는 것으로 판단되었다. 제주지역에서 확인된 특산식물 중 전체적으로 90.9%가 유용성이 있는 것으로 나타나고 있으며 아직까지 유용성에 대한 정보가 미흡한 종도 자원적인 연구접근에 따라 다양한 자원으로 활용가치가 있는 것으로 판단된다.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.160-166
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• 2014

This study was aimed at looking into the distribution status and age structure of Abies holophylla population in Sudo-Am temple forest. It was found that a total of 302 individuals of Abies holophylla existed which were more than 2m in height within the study area. Furthermore the population size is one of the largest in the southern region of Korea. The CBH of Abies holophylla ranged from 1.5 cm to 500.8 cm. Age structure of Abies holophylla looks like a gourd-shaped bottle. This means that they have an unstable structure status and do not survive very long. This status results from a variety of factors including, vegetation succession, anthropogenic activities, and global warming. The environmental characteristics of Abies holophylla population was $931{\pm}64.5m$ in mean altitude, $19.2{\pm}8.7^{\circ}$ in mean slope in the northeastern and southeastern area of the slope direction, and $1,324,323{\pm}174,459wh\;m^{-2}$ in average of direct normal irradiation. Among the site environmental factors, the significant ones which influence the potential habitat for Abies holophylla distribution were chosen using the MaxEnt model. According to the results of this study, altitude and slope were found as the important factors. The average value of environmental conditions by ROC analysis were altitude 903.2 m, slope $20.04^{\circ}$, irradiation $1,352.248wh\;m^{-2}$, and the southeastern aspect.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.657-663
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• 2014

This study was conducted to investigate the difference in feeding habits of Red-Tongued Viper Snakes, according to available foods sources and areas. The effects of differences in food sources were found on Red-Tongued Viper Snake inhabited in the Jeju Island and its islet Gapado, from May 2006 to Nov. 2010. The food sources for the Red-Tongued viper snake population in the Jeju Island were found to be as follows: Chinese red-headed centipedes (Scolopendra subspinipes mutilans), Jeju Salamanders (Hynobius quelpaertensis), Japanese tree Frogs (Hyla japonica), Narrow-mouthed Toad (Kaloula borealis), Dybowski's Brown Frogs (Rana dybowskii), Black-spotted Pond Frogs (Rana nigromaculata), Smooth Skinks (Scincella vandenburghi), Asian Keelback Snakes (Amphiesma vibakari), Lesser White-toothed Shrews (Crosidura shantungensis), Hallasan Shrews (Sorex caecutiens hallamontanus), and Jeju Striped Field Mice (Apodemus chejuensis). This implies that Red-Tongued Viper Snakes mainly feed on amphibians, reptiles, and small mammals. Among these, amphibians occupied the highest portion at 55.2% followed by mammals at 20.7%, centipedes at 13.8%, and reptiles at 10.3%. On the contrary, Red-tongued viper snake population in Gapado only feed on Chinese red-headed centipedes and Smooth Skinks (S. vandenburghi). Since only a small amount of nutrient can be obtained from Chinese red-headed centipeds or Smooth Skinks, this feeding habit for Red-tongued viper snake would adversely effect on the growth or regeneration. The reason why Red-Tongued viper snake population in the Gapado mainly feed on Lizard and Centipedes in spite of relatively various available food sources, might be due to the low density of other food sources in the Gapado. Red-Tongued viper snake could be feeding on foods that are low in quality but are easily accessible, to minimize energy consumption on searching for other more nutritious foods. A snake tends to select the size of its food depending on the size of its own head. The positive correlation was found between the size of the heads of Red-Tongued viper snakes from the Jeju island and the diameter of their foods. The head size was larger in the males than females in viper snake population from the Jeju Island, which might effect on their selection of foods. However, no significant difference was found between the sizes of the head and the food in the Red-Tongued viper snake population from the Gapado. The findings of this study would provide meaningful data, which directly shows that even within the same viper species they choose different available food sources according to their inhabitance. This leads to their growth and adaptation to their environment which is beneficial for sustaining of its population.

• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.80-94
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• 2024

This study aimed to examine the morphological characteristics and variation in main traits by comparing the growth of individuals of Ecklonia cava Kjellman(Laminariales, Phaeophyceae) under an aquaculture environment. This survey was conducted from April 2018 to November 2019 at the aquafarm in Jindo-gun, Jeollanam-do(South coast of Korea). To classify the morphology of individuals in the aquaculture farm of E. cava, we investigated fourteen morphological characteristics and calculated four ratios between the measured values. Juvenile individuals showed a simple or oblong lanceolate, and at 3-4 months, a short stipe and holdfast developed, along with a bladelet that developed into the secondary blade form. At 5-7 months, secondary blades were found to develop irregularly on the primary blade. At 8-10 months, the primary blade expanded and secondary blades elongated. At 11-12 months, the secondary blades became oblong. At 13-14 months, the thallus area expanded. At 15-16 months, tertiary blades were formed, the thallus became more complex, the stipe thickened, and the holdfast widened. At 17-18 months, secondary blades clearly developed along with lobes. At 19-20 months, tertiary blades developed and became similar to mature natural blades. In the principal component analysis (PCA), the monthly population of the first year(Q1) and that of the second year(Q2) of the cultured population were divided along PC1, which is related to secondary blade morphological characteristics and the holdfast width. Q2 and natural populations are distributed in descending order of volume in Jeju(J), East Coast(E), and South Coast(S) along PC2, which is related to primary blade and stipe morphological characteristics. The results of this study were judged to offer important criteria for the development of different varieties of E. cava.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.127-136
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• 2020

This study was conducted to investigate the population characteristics of Nile tilapia (Oreochromis niloticus) in the Daegu Metropolitan City thermal effluent stream (Dalseo Stream) from January to November 2019. The collected fish were identified as 4,247 individuals of 20 species from a total of eight families. The dominant species was O. niloticus with 1,306 individuals and a high relative abundance (30.75%). The water temperature of Dalseo Stream was maintained above 10℃ throughout the year, which means that O. niloticus could inhabit it even in winter. The length-weight analysis showed a regression coefficient b of 3.1496, and a condition factor (k) of 0.0025 with a positive slope. Comparing the water temperature of Dalseo Stream and the total length of O. niloticus per investigation period, the 0-age individuals appeared May 29 when the water temperature was maintained above 22℃. In conclusion, the thermal effluent of Dalseo Stream allowed O. niloticus to survive in winter and maintain stable growth conditions and life cycles. The results of this study will inform ecological information on O. niloticus, which suggests that river management efforts should consider the management of O. niloticus populations for the conservation of fish species diversity.

• The Korean Journal of Malacology
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• v.13 no.2
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• pp.193-201
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• 1997

1990년 3월부터 1991년 2월까지 전라북도 군산 연안에 서식하는 동죽을 채집하여, 순간성장율, 순간사망율, 평균 생체량, 연간 생물생산력에 대하여 조사하였다. 치패는 각장 약 0.75 mm가 7월에 처음 채집되었으며, 0-5세의 6개 cohort로 구분되었다. 순간성장률은 여름철에 ？고 겨울철에 낮았지만, 순간사망률은 여름철에 높았다. 조사지역에서 동쪽 개체군의 연간평균 생체량은 3.865 g/$m^2$이었으며, 연간생산량은 3.933 g/$m^2$이었고, 연간 회전율은 1.020, 회전시간은 0.986년으로 추정되었다.