• Korean journal of applied entomology
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• v.34 no.4
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• pp.391-405
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• 1995

Cockroach survey on the relative density from 7 different habitats including hotel-ins, tea-rooms restaurants, hospitals, apartments, and resident hoses were conducted in 3 District(Ku) areas in Suwon city during the period of February through October, 1994. of a total of 3.039 trap sets, Cockroaches were collected from 1,435 traps, comprised of a 47.22% positive trap-rate. Chinese restaurants were shown to be the highest positive trap-rate of 72.67% of the total while the other habitats such as Korean restaurants, apartments, resident hoses, tea-rooms, hotel-inns, and hospitals were 60.67%, 58.61%, 52.22%, 38.67%, 24.88%, and 17.54%, respectively. Blattella germanica was shown to be the highest population density of 55.01 individuals/trap/week comprised of 97.36% of the total during survey period whereas the other 3 species, Periplaneta japonica, P. americana, and P. fuliginosa constituted in lesser extent of 2.35%, 0.14%, respectively. Of a total of 7 different cockroach breeding habitats, higher population density per trap/week was from restaurants with averages of 20.56 and 8.31 cockroaches from Chinese and Koran restaurants, respectively. An intermediate extent of density was observed from apartments, tea rooms and resident houses with 5.33, 3.79 and 3.53 individuals, respectively. Lower relative densities of cockroaches were observed from hospitals and hotel-inns with averages of 0.18 and 1.00 individuals per trap/week, respectively.

• Korean journal of applied entomology
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• v.36 no.3
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• pp.215-223
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• 1997

A matrix model of rice weevil population based on degree day (DD) was constructed. The basic matrix model predicted on exponential jncrcase of the adult weevil density and the finite rate of increase(h) of the population was estimated to be 2.155/100DD. Adult density simulated by the matrix model including intraspecific competition showed a damped oscillation over time and reached at the stationary level of 530 at 69, 300DD. The experimental population showed similar features to that of the model. But there were some differences in the highest density and period of adult oscillation. The differences could largely be caused by the assumption of the model; resource constancy.

• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.55-65
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• 1984

韓國內 9個道別 地域 가운데 5個道의 駐韓美軍事地域에서 39個의 誘蚊燈에 의하여 2,114 Trap night를 稼動하여 2년동안 채집하여 얻은 결과는 다음과 같다. 1. 3屬, 14種, 65,847마리의 암모기가 收集되었으며 금빛 숲모기, 중국 얼룩날개 모기, 빨간 집모기, 작은 빨간 집모기가 가장 넓게 분포되어 主種을 이루었다. 2. 작은 빨간 집모기가 수집된 전체 암모기의 55.4%를 차지하였으며 5개도 전역에 걸쳐 분포되었으나 90% 이상이 평택지역에서 수집되었다. 이 종은 7월부터 수집되기 시작하여 8월에 가장 높은 개체군 밀도를 나타내고 9월부터 감소한다. 1982년 채집된 모기수는 1981년 모기수의 5배에 達했다. 3. 중국 얼룩 날개 모기는 수집된 전체 암모기수의 28.2%를 나타냈고 5월부터 散發的으로 나타나서 7,8월에 높은 개체군 밀도를 보이고 9월부터 감소한다. 1981년과 1982년의 채집된 모기수는 큰 差異를 나타내지 않았다. 4. 금빛 숲모기는 수집된 전체 암모기수의 8.8%를 나타냈고 5개도 전역에 걸쳐 발생하나 주로 지방에서 수집되었다. 이 종은 5월부터 나타나서 6월에 가장 높은 개체군 밀도를 보이고 그후부터 감소하는 경향을 보이나 8월에 다시 조금 높은 발생을 나타내나 6월의 그것에 비하여 낮다. 5. 빨간 집모기는 전체 암모기수의 5.3%를 차지하였고 5개도 전역에 여름에 걸쳐 고루 분포되었다. 6. Anopheles lesteri는 평택지역에서 네마리가 채집되었으나 이 종은 중국 얼룩 날개 모기와 형태학적인 區分이 어려워서 더욱 면밀한 考察이 필요되어지며 나머지 9종의 모기는 매우 적은 수가 채집되었다. 7. 살충제와 모기 驅除法에 관하여 간락하게 논의되었다.

• Korean Journal of Environment and Ecology
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• v.19 no.3
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• pp.269-278
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• 2005

The dynamics and distribution characteristics of Coryjopsis coreana popujation at Cheongsogol, Sunchon, Cholanam-do, Korea, were investigated. The Coryiopsis coreana pop ulation was distributed along the forest edge and it showed characteristics which were distributed on only directional slopes of the north, northeast or northwest. The Coryjopsis coreana constituted subtree or shrub layer in the forest, and its floristic composition was basically similar to those of adjacent areas where the species does not exist. The number of stump was 6.25 per $25\;m^2$, and each stump had 3 sproutings in average. The density of the Corylopsis coreana population in the study area was lower than that in other area, which suggests the population is declining in the study area.

• Korean journal of applied entomology
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• v.54 no.2
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• pp.73-81
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• 2015

A Cohort based model for temperature-dependent population dynacmics of Riptortus pedestris was constructed by using a commercial software (DYMEX) and seasonal occurrence along with pesticide treatments effect was simulated and validated with pheromone trap data. Ten modules of DYMEX software were used to construct the model and Lifecycle module was consisted of seven developmental stages (egg, 1 - 5 nymphal instars, and adult) of R. pedestirs. Simulated peaks of adult populations occurred three or four times after the peak of overwintered populations which was similar to those observed from pheromone trap catch. Estimated dates for the second peak were quite similar (1-2 day difference) with those observed with pheromone trap. However, the estimated dates for the first population peak were 9-16 days later than the observed dates by pheromone trap and the estimated dates for the last peak were 17-23 days earlier than the observed dates. When insecticide treatments were included in the simulation, the biggest decrease in R. pedestris adult density occurred when insecticide was applied on July 1 for the first peak population: the estimated adult density of the second peak was 3% of untreated population density. When insecticide was assumed to be applied on August 30 for the second peak population, the estimated adult density of the following generation was about 25% of untreated population and the peak density of the following generation reached about two weeks later than untreated population. These results can be used for the efficient management strategies for the populations of R. pedestris.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.257-264
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• 1991

Studies on the geographical distribution and the seasonal prevalence of chigger mites, with particular reference to L. paflidum, a vector species of tsutsugamushi disease were carried out during the period of July 1989-October 1990. From total 111 field rodents collected during the study period, 4,498 chiggers were obtained and 12 species of 4 genera were identified. L. paflidum, the vector species was the dorninant species, showing 65.6% of the total chiggers. L. scutellare, known as the important vector species of tsutsugamushi disease in Japan was not found in the study area, except Yesan-gun, Chungcheong-namdo where only one specimen was collected. The distribution of chigger mites was clearly localized by species, showing the different dominant species by locality. The population density of L. paflidum was high at two study areas, moderate at one area and very low at six other areas, compared to the other species. The study on seasonal prevalence of L. paflidum population density resulted that they started appearing in September (9.8%), showed the peak in October (45.4%) and November (30.6%), almost disappeared during the period of December-March (1.3-0%), reappeared in April (12.7%) showing a small peak, and again almost disappeared until September. L. palpafe was appeared only in winter and spring (December-April).

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.71-74
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• 1998

HMM (hidden Markov model)을 이용한 음성인식은 현재 가장 널리 쓰여지고 있는 방법으로, 이 중 CDHMM (continuous observation density HMM)은 상태에서 관측심볼확률을 연속확률밀도를 사용하여 표현한다. 본 논문에서는 가우스 혼합밀도함수를 사용하는 CDHMM의 상태천이확률과, 관측심볼확률을 표현하기 위한 인자인 평균벡터, 공분산 행렬, 가지하중값을 유전자 알고리듬을 사용하여 최적화하는 방법을 제안하였다. 유전자 알고리듬은 매개변수 최적화문제에 대하여 자연의 진화원리를 모방한 알고리듬으로, 염색체 형태로 표현된 개체군 (population) 중에서 환경에 대한 적합도 (fitness)가 높은 개체가 높은 확률로 살아남아 재생 (reproduction)하게 되며, 교배 (crossover)와 돌연변이 (mutation) 연산 후에 다음 세대 개체군을 형성하게 되고, 이러한 과정을 반복하면서 최적의 개체를 구하게 된다. 본 논문에서는 상태천이확률, 평균벡터, 공분산행렬, 가지하중값을 부동소수점수 (floating point number)의 유전자형으로 표현하여 유전자 알고리듬을 수행하였다. 유전자 알고리듬은 복잡한 탐색공간에서 최적의 해를 찾는데 효과적으로 적용되었다.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.639-650
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• 2022

Abeliophyllum distichum Nakai, a rare plant with distylous characteristics, is native to certain parts of the Korean Peninsula. It is registered on the IUCN Red List of Threatened Species as a globally endangered plant. This study was conducted to establish an appropriate local conservation management plan suitable for future A. distichum populations by comparing and analyzing the flowering characteristics and population size according to distyly based on the results of quantitative surveys in 14 regions, including 8 areas with native populations of A. distichum and 6 natural monument populations. The number of individuals appearing in each population group was surveyed, and the flowering individuals were identified by style as being either pin or thrum flower types as they were being examined and recorded on the site. In total, 13,130 individuals of A. distichum (7,003 flowering and 6,127 non-flowering individuals) were recorded, but the balance of the number of pin- and thrum-flowered individuals in each population was not significant (p<0.05), indicating an imbalanced state. In particular, the Yeongdong (YD) population was very disproportionate compared to other populations, suggesting that its genetic diversity was low and the possibility of inbreeding was high. The average flowering and fruiting rates by management unit were much higher in the natural monument populations (89.2% and 55.3%, respectively) than in the natural habitat populations (39.0% and 8.5%, respectively). It may be due to a difference in reproductive growth resulting from light inflow into the forest caused by the upper crown closure. The area of occupation (AOO) of A. distichum on the Korean Peninsula covered an area of 23,224.5 m². Although the natural monument population was smaller than the natural habitat population, its density was higher, likely as a result of the periodic management of natural monument populations, where the installation of protective facilities in certain areas restricts population spread. Conservation of A. distichum populations requires removing the natural monument populations suspected of anthropogenic and genetic disturbances and expanding the conservation priority population by designating new protected areas. Although the habitats of natural monument populations are managed by the Cultural Heritage Administration and local governments, there are no agencies that are responsible for managing natural habitat populations. Therefore, institutional improvement in the overall management of A. distichum should be prioritized.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.287-293
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• 2005

This study was conducted to evaluate the effect of the conventional pesticide application system on the rice spider community based on the quantitative investigation of arthropod community in the rice fields in Saran area, Hwasung-si, Kyeonggi-do from 1996 to 1998. Spiders were the highest dominant group comprising over 90% of all natural enemies in their density, and showed very stable yearly occurrence. In these fiekds the mean density of spiders was about 10 individuals/$0.25m^2$ during the rice growing season, and three families including Lycosidae, Tetragnathidae and Linyphiidae were very abundant. The colonization of spiders occurred in early season and they showed rapid density increase in mid-season. They maintained the highest density to the late season and their density decreased at harvest season. In the years of the low rice pest occurrence, the disturbance effect on spider community by pesticides were less. Two dominant species, Pirata subpiraticus and Pachygnatha clerki, had different population dynamics; Pirata subpiraticus showed the rapid density increase in the mid-July, and most of them remained immature stages, however, in the case of Pachygnaths clerki population, they rapidly increased in the late August and most of them remained adult stage during the late growing season.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.304-312
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• 2004

The transient dynamics of three-trophic populations (prey, predator, and super predator) using ratio-dependent models responding to environmental impacts is analyzed. Environmental factors were divided into two parts: periodic factor (e.g., temperature) and general noise. Periodic factor was addressed as a frequency and bias, while general noise was expressed as a Gaussian distribution. Temperature bias ${\varepsilon}$, temperature frequency ${\Omega}$, and Gaussian noise amplitude ${\`{O}}$ accordingly revealed diverse status of population dynamics in three-trophic food chain, including extinction of species. The model showed stable limit cycles and strange attractors in the long-time behavior depending upon various values of the parameters. The dynamic behavior of the system appeared to be sensitive to changes in environmental input. The parameters of environmental input play an important role in determining extinction time of super predator and predator populations.