• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.548-557
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• 2021

Cypripedium japonicum Thunb. is an endemic plant in East Asia, distributed only in Korea, China, and Japan. At the global level, the IUCN Red List evaluates it as "Endangered Species (EN)," and at the national level in Korea, it is evaluated as "Critically Endangered Species (CR)." In this study, we investigated the characteristics of the age structure and the sustainability of the population based on the data obtained by demographic monitoring conducted for seven years in the natural habitat. C. japonicum habitats were observed in 7 regions of Korea (Pochoen, Gapyeong, Hwacheon, Chuncheon, Yeongdong, Muju, Gwangyang), and 4,356 individuals in 15 subpopulations were identified. The population size and structure differed from region to region, and artificial management had a very important effect on the size and structural change of the population. Population viability analysis (PVA) based on changes in the number of individuals of C. japonicum showed a very diverse tendency by region. And the probability of population extinction in the next 100 years was 0.00% for Pocheon, 10.90% for Gwangyang, 24.05% for Chuncheon, and 79.50% for Hwacheon. Since the above monitored study sites were located within the conservation shelters, which restricted access by humans, unauthorized collection of C. japonicum, the biggest threat to the species, was not reflected in the individual viability. So, the risk of extinction in Korea is expected to be significantly higher than that estimated in this study. Therefore, it is necessary to reflect population information in several regions that may represent various threats to determine the extinction risk of the C. japonicum population objectively. In the future, we should expand the demographic monitoring of the C. japonicum population known in Korea.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.282-285
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• 2016

Peregrine falcon (Falco peregrinus) are listed as endangered species and Natural monument #323 in Korea, and this study examined the possibility of extinct of peregrine falcon in Jang Hang wetland near Han river using with the application of Population Viability Analysis (PVA) technique. In Jang Hang wetland areas population was monitored during 1999-2005 averaging 10.8 individuals and PVA analysis was done for the 5 years (2015-2020) using the average population size. Using the initial population was estimated 20% of extinct rate during the time. This estimation was quite low considering water pollution and loss of habitat. Also PVA only used population size lacking in other life history information. Nonetheless falcon population can be in risk of extinction if the current construction of crossovers in the river, cement bank are maintained. Long term information regarding life history needs essential.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.393-394
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• 2020

세 군 매칭을 수행하여 관찰 데이터를 구축하고 통계분석에 기반한 연구를 수행하는 경우가 종종 발생한다. 매칭작업은 각 군에 속한 개체의 성향점수를 서로 비교해 거리가 가까운 짝을 찾아야 하므로 카테시안 곱 만큼의 경우의 수를 따져야 하는 문제이고, 메모리 소요가 크다. 특히 세 군 매칭은 세 쌍의 거리가 가까운 triplet을 찾는 문제로, 세 개체 사이에 존재하는 세 개의 거리를 따져야 하기 때문에 메모리 소요가 두 군 매칭에 비해 훨씬 크다. 각 군에 속한 개체가 늘어나면 메모리소요가 기하 급수적으로 늘어나게 된다. R패키지에 포함된 TriMatch함수는 세 군 매칭 수행을 위해 가장 널리 사용되는 프로그램이다. 이 프로그램은 세 개체 사이의 세 개 거리가 가장 짧은 triplet을 찾는 방식으로 구현 되었다. 이 프로그램은 메모리 소요가 매우 커 각 군에 속한 개체의 수가 많아지면 메모리 부족 에러가 발생하는 경우가 많다. 본 연구에서는 세 군 매칭에 소요되는 메모리 소요를 줄일 수 있는 알고리즘을 제안하고자 한다. 이 알고리즘의 구현을 통해 각 군에 속한 개체가 늘어나도 안정적인 세 군 매칭 결과를 얻을 수 있을 것으로 기대한다.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.1
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• pp.66-72
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• 1999

In this paper, we suggest a new lifetime allocation method of genetic algorithm with varying population size. This method can control the size of the population according to the fitness values. The population size is stabilized near the neighbourhood of the optimal value. We used the diploidy method in the coding of the chromosomes. Several simulations confirm that the new allocation method can control the size of the population.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.35-42
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• 2004

To examine the species composition and population fluctuation of butterflies at Mt. Yudal, Mokpo, we collected butterflies from May, 2001 to April, 2002 by dividing the study site into four subyegions. As a result, seven families comprising 40 species were identified. The patterns of population fluctuations at the four subregions showed that the lower the elevation the higher the number of species and individuals. Monthly fluctuations of buttefly species produced an M-shaped curve, whereas those of individuals produced a monotonic curve with a maximum peak during August. To see effectively the changes of numbers of species and individuals, we calculated the indices of species richness and evenness by subregions and months. As a result, both indices fulfilled the primary criterion of independence and showed more or less negative association: when heterogeneity is higher, evenness is lower. Examination of butterfly populations over long-term periods might provide an evidence of global warming and a guideline to conserve and manage habitats.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.2
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• pp.113-120
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• 2024

The population sparseness index(PSI) is being utilized to describe the functioning of internal layers in artificial neural networks from the perspective of neurons, shedding light on the black-box nature of the network's internal operations. There is research indicating a positive correlation between the PSI and performance in each layer of convolutional neural network models for image classification. In this study, we observed the internal operations of a convolutional neural network when adversarial examples were applied. The results of the experiments revealed a similar pattern of positive correlation for adversarial examples, which were modified to maintain 5% accuracy compared to applying benign data. Thus, while there may be differences in each adversarial attack, the observed PSI for adversarial examples demonstrated consistent positive correlations with benign data across layers.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.236-243
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• 2012

The leaf growth and physiological characteristics of Forsythia saxatilis were investigated at six natural habitats under different light intensities in Bukhansan in order to figure out an appropriate growth environment for conservation and restoration of F. saxatilis that is Korean endemic plant designated as rare and endangered species. Relative light intensities (RLI) at six habitats showed from 10% to 78% of the full sun. Leaf length, leaf width, leaf area and dry leaf weight of population under highest relative light intensity (78%) were the highest. The ratio of dry leaf weight to leaf area increased with the increase of RLI. The content of photosynthetic pigments such as chlorophyll a, b and carotenoid were the highest at 78% of RLI, whereas the ratio of total chlorophyll to carotenoid content reduced according to the increase of RLI. Photosynthetic parameters, such as photosynthetic rate, also increased with the increase of RLI. The total nonstructural carbohydrate (TNC) was 1.5 times higher at 78% of RLI than that at 10% of RLI and the total soluble sugar (TSS) was the highest at 78% of RLI. In conclusion, leaf characteristics and physiological characteristics have high positive correlation with light intensity. Therefore, light condition should be primarily considered to improve growth and physiology characteristics of F. saxatilis under low light intensity.

• Journal of Wetlands Research
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• v.20 no.2
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• pp.124-130
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• 2018

This study was conducted to identify the characteristics of bird population dynamics using unmanned monitoring system in rice paddy. We compared the similarity of population dynamics of birds between unmanned monitoring system and field survey, and evaluated the spatial and temporal patterns of population dynamics of birds using the unmanned monitoring system. The monitoring using the system was conducted from January 1, 2014 to December 31, 2016 in Cheolwon, Dangjin, Buan, and Heanam. The images from the system were obtained at 10-min intervals from 6:00 to 20:00. The field survey was conducted once a month in Dangjin from January to December 2016. Total 91,980 images were obtained from the unmanned monitoring system. We extracted the number of individuals for herons, shorebirds, and waterfowl from the images. The population dynamics of waterbirds using the unmanned monitoring system were similar to that in field survey. Especially, population dynamics of herons was more similar than other waterbirds. It was identified that the population dynamics of herons using the unmanned monitoring system was different among the Cheolwon, Dangjin, Buan, and Heanam. Furthermore, the unmanned monitoring system was available on various time scale such as month, day, and minute. It is expected that long-term data storage using the unmanned monitoring system can be used to identify in detail and forecast the population dynamics of birds in rice paddy.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.402-412
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• 2020

This study aims to examine the population characteristics of the fish and the bluegill (Lepomis macrochirus), designated as ecologically disturbing fish, living in four water dams in the Ulsan area and to provide basic data. The survey of fish living in 4 water dams and surrounding tributaries in the Ulsan area from 2016 to 2017 found a total of 1,987 individuals of 28 species of 9 families and identified 6 Korea's endemic species is (21.4% indigenous rate), 4 exotic species, and 2 ecosystem disturbing species. Based on the number of fishes identified, the dominant species was Lepomis macrochirus, and the subdominant species was Hemiculter eigenmanni. The investigation of the age structure of the L. macrochirus found in the 4 water dams in the Ulsan area showed a large population of 1 to 2 old, and the population was growing fast. Moreover, the analysis of the total length-weight relationship and obesity of the L. macrochirus population showed that the regression coefficient b of the total length-weight relationship was greater than 3.0, and the habitat of the L. macrochirus population was in good condition. Obesity had a positive slope, and the growth state was relatively good. The result of this study can be used as useful data to predict the trend of the L. macrochirus fauna inhabiting in 4 water dams in the Ulsan area.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.658-675
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• 2016

The environmental characteristics of the habitats, the population structures, ecological niche, life traits and the population demography are used as an essential informations to the effective conservation plans about the target species. We first confirmed a total of 37 populations through 12 years of investigation on the extents, and investigated the environmental factors of habitats and the population structures of the 25 cohorts in 12 regions among them. And, we investigated the population dynamics targeting at 8 cohorts in the population of Daegwanryeong-myeon, Pyeongchang-gun, Gangwon-do. Along with this, we conducted 4 years of cultivation experiments and how pollinators affect the success of reproduction. The results shows that the Paeonia obovata Maxim. was found in a relatively wide range of habitats. For the population structures of the 25 cohorts, there were considerable differences among cohorts, including a case which showed relative stable structure and an extreme case in which only adults were found. The factor that affected the population dynamics during the investigation was thought as a forest gap created in the tree layer. In the cultivation experiment, seedlings grew well in a less soil organic matter. The seed setting rate and the number of seeds generated by visiting pollinators were higher trends. In conclusion, to understand the distribution of the Paeonia obovata Maxim., there needs to be investigated on the other factors that are involved in dispersal factors other than environmental factors, and thus we suggest the necessity of the research on the dispersal vectors. The current Paeonia obovata Maxim. population was thought as a process of expansion after the rapid reduction of the extents in the past. For the effective conservation of the Paeonia obovata Maxim., an endangered plant, we recommend to understand the species through the spatio-temporal expansion, and maintain the health of the ecosystem based on it.