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

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2002.11a
• /
• pp.81-81
• /
• 2002

• Korean Journal of Environment and Ecology
• /
• v.33 no.3
• /
• pp.303-320
• /
• 2019

Plants interact with various biotic and abiotic environmental factors. It requires much information to understand the traits of a plant species. A shortage of information would restrict the assessment, especially in the evaluation of what kind of factors influence a plant species to face extinction. Polygonatum stenophyllum Maxim. is one of the northern plants of which Korea is the southern distribution edge. The Korean Ministry of Environment had designated it to be the endangered species until December 2015. Although it is comparatively widespread, and a large population has recently been reported, it is assessed to be vulnerable due to the low population genetic diversity. This study evaluated the current distribution of Polygonatum stenophyllum Maxim. We investigated the vegetational environment, population structures, phenology, soil environment, and self-incompatibility based on the results. Lastly, we evaluated the current threats observed in the habitats. The habitats tended to be located in the areas where the masses at the edge of the stream accumulated except for those that were located on slopes of some mountainous areas. Most of them showed a stable population structure and had re-established or recruited seedlings. Polygonatum stenophyllum Maxim. had the difference in time when the shoots appeared above the ground depending on the depth of the rhizome located in the underground. In particular, the seedlings and juveniles had their rhizome located shallow in the soil. Visits by pollinator insects and success in pollination were crucial factors for bearing of fruits by Polygonatum stenophyllum Maxim. The threats observed in the habitat of Polygonatum stenophyllum Maxim. included the expansion of cultivated land, construction of new buildings, and construction of river banks and roads. Despite such observed risk factors, it is not likely that there would be rapid population reduction or extinction because of its widespread distribution with the total population of more than 2.7 million individuals and the new populations established by the re-colonization.

• Korean Journal of Environmental Biology
• /
• v.39 no.1
• /
• pp.108-118
• /
• 2021

The purpose of this study was to provide baseline ecological data for the conservation of the Manchurian trout habitat through the investigation of the growth status of Brachymystax lenok tsinlingensis, and Pearson's correlation analysis (PCA) between the B. lenok tsinlingensis population and the use of the land around Gyebangcheon stream. Sampling was conducted twice in July, September, and October 2018. During the July and September surveys, 882 individuals belonging to 13 species from six families were collected. The dominant species was Rhynchocypris kumgangensis and the subdominant species was Zacco koreanus. The total number of B. lenok tsinlingensis collected was 99. The results of the length-weight relationship in the B. lenok tsinlingensis population were analyzed with a regression coefficient b value of 3.1272 and a condition factor (k) value of 0.0006. Therefore, the growth condition of B. lenok tsinlingensis was regarded as fairly good. The QHEI(Qualitative habitat evaluation index) value in the B. lenok tsinlingensis habitat was 119.5(±0.5)-153.5(±0.5), indicating optimal-suboptimal conditions. As a result of the HIS (Habitat suitability index) analysis, it was confirmed that the optimal habitat for B. lenok tsinlingensis was 0.45-0.55m and >1 m in water depth, 0.55-0.65 m s^-1 in water velocity, and boulder in the substrate. The ratio of the land use in this study site was analyzed as 66.26-96.31% for forest and grassland areas, 0.00-23.79% for agricultural areas, 0.00-4.19% for urbanized areas, and 3.69-8.87% for others. Correlation analysis of the number of B. lenok tsinlingensis and various factors revealed statistically significant correlations between QHEI and forest and grassland areas, agricultural areas, and urbanized areas.

• Korean Journal of Environment and Ecology
• /
• v.25 no.6
• /
• pp.878-886
• /
• 2011

The fish fauna and characteristic of population of Brachymystax lenok tsinlingensis at the 7 stations in the Bonghwa-gun were investigated from June 2010 to May 2011. The collected species during the survey period were 15 species belong to 7 families. Protected species by the legal were B. lenok tsinlingensis, Koreocobitis naktongensis, and Cottus koreanus. Korean endemic species were Microphy sogobio yaluensis, Coreoleuciscus splendidus, Zacco koreanus, Cobitis hankugensis, K. naktongensis, Iksookimia longicorpa, Niwaella multifasciata, Liobagrus mediadiposalis, C. koreanus, and Coreoperca herzi, which showed a ration of 66.7% in collected species. Dominant species were Z. koreanus(St. 1), B. lenok tsinlingensis(St. 3, 4, 5), and Rhynchocypris oxycephalus(St. 2, 6, 7). Length-weight relation in the population of B. lenok tsinlingensis was BW = $0.000008TL^{3.02}$, and condition factor in the population was average 0.84. Frequency analysis of total length indicated that the group 80~180 mm in total length is represented by one-year-old individuals, the group 200~300 mm by two-year-old individuals, and the group over 300 mm by three-year-old individuals. The density of population was presumed average 17 individuals per 100$m^2$ and total 4,760 individuals in the reservation for B. lenok tsinlingensis.

• Korean Journal of Ecology and Environment
• /
• v.45 no.3
• /
• pp.322-328
• /
• 2012

To estimate the population size of Miho spine roach (Cobitis choii), one of national monument species in Korea, multiple mark-recapture experiments (Jolly-Seber model) by VIE tagging were conducted in the upper region of the Backgok Stream located in the Kum-River system, Korea. Fish sampling was conducted at four different times from October 5 to October 26, 2011. A total of 335 sampling points were sampled, where the species was determined in 217. The population size was estimated to be 6,143 in this study. Compared to a previous report conducted by the Korean Ministry of Environment (2009), the population size of this species has decreased by 41%. The reasons for population decline are thought to be due to loss of microhabitat, sedimentation, water pollution. Consequently, a habitat restoration program is required to protect the microhabitat and recover the population size in this area.

• Korean Journal of Environmental Biology
• /
• v.24 no.4
• /
• pp.307-313
• /
• 2006

Seasonal variation of marine bacterial community was analyzed in the surface sea water collected from one of the stations locating at Tongyeoung coastal area, Korea. The results obtained by the culture method through identification with the VITEK Microbe ID system after pure culture in the selective medium were compared with those obtained by the DGGE based 16S rRNA PCR method. The composition of the marine bacterial community in the sea water samples harvested in September, 2004, November, 2004, January, 2005, May, 2005 and August, 2005 determined by the culture method showed 5, 5, 4, 6, and 10 strains respectively. Pseudomonas fluorescens and Acinetobacter lwoffii were detected in all seasons. The other strains were identified to be Pseudomonas stutzeri, Sphingomonas paucimobilis, Burkholderia mallei and Chryseobacterium indologenes. In contrast, the 16S rRNA PCR-DGGE method detected 10, 11, 6, 9 and 13 populations respectively in the same sea water samples and the strains were identified to be Acinetobacter lwoffii, Burkholderia mallei, Pseudomonas fluoresence, Actinobacillus ureae, Burkholderia sp., Pseudomonas stutzeri, Roseobacter sp., Vibrio parahaemolyticue, Sphingomonas paucimobilis and Rugeria algocolus. This results indicated that the DGGE based 16S rRNA PCR method was more efficient than the culture method for the grasp of the characteristics of the marine bacterial community.

• Korean journal of applied entomology
• /
• v.43 no.4 s.137
• /
• pp.311-315
• /
• 2004

The brown planthopper, Nilaparvata lugens, is among the most serious insect pests of rice. It is widely distributed in Asia, Australia and Pacific islands. An earlier mitochondrial DNA study revealed that there exist significant genetic differences between populations north and south of the Red River Delta region in Vietnam. However the mitochondrial DNA was not sufficiently variable to examine the sources of immigration. For a more detailed analysis of geographic population structure of N. lugens, we developed microsatellite markers. Thirty-seven putative microsatellite loci were isolated using a magnetic biotin method, and five primer pairs designed from the flanking regions of sequenced microsatellite clones were labeled with fluorescent. Of these five primer sets, two have proven to be useful across all the samples we used in this study. We used variation at these two microsatellite loci to test the hypothesis that N. lugens biotypes (1, 2, and 3) sampled from laboratory selection constituted distinct genetic units. Allele frequency differences among the three major biotype categories were not significantly different at one locus (27035). However, the other (7314) did show differences among the major three biotypes. The methods we describe here will be useful for studying population structure of crop pest and for tracking the patterns of migratory pest like the rice planthoppers.

• Korean Journal of Environmental Biology
• /
• v.34 no.3
• /
• pp.193-200
• /
• 2016

Toxicity assessment of heavy metals (As, Cr and Pb) has been investigated by using the rate of survival and population growth(r) of marine rotifer, Brachionus plicatilis. The survival rate was determined after 24 hours of exposure to As, Cr and Pb. As and Cr reduced survival rate in dose-dependent manner and a significant reduction were occurred at concentration of greater than 30 and $150mg\;L^{-1}$, but Pb had no effect on survival rate. The r was determined after 72 hours of exposure to As, Cr and Pb. As, Cr and Pb reduced r in dose-dependent manner and a significant reduction were occurred at concentration of greater than 5, 25 and $50mg\;L^{-1}$. The toxicity of heavy metals were ranked As>Cr>Pb, with $EC_{50}$ values of 12.98, 82.34 and $110.14mg\;L^{-1}$, respectively. The no-observed-effect-concentration (NOEC) of r in As, Cr and Pb exposure were 1, 12.5 and $50mg\;L^{-1}$, respectively. The lowest-observed-effect-concentration (LOEC) of r in As, Cr and Pb exposure were 5, 25, and $50mg\;L^{-1}$, respectively. From the results, the concentration of As, Cr and Pb (greater than 5, 25 and $50mg\;L^{-1}$, respectively) have toxic effect on the r of B. plicatilis in natural ecosystems. These results (including NOEC and $EC_{50}$) might be useful for the mixing toxicity assessment and toxic guide line of heavy metals in marine ecosystems.

• Korean Journal of Ecology and Environment
• /
• v.40 no.3
• /
• pp.412-418
• /
• 2007

The dynamics of Zacco platypus population of upstream and downstream in the lake Hoengseong, Korea were investigated from April to October 2005. Length-weight relationship, condition factor (K) and relative condition factor $(K_n)$ of Z. platypus were compared by the study stations. The equations based on length-weight relationship in the lake Hoengseong were $Log(T_w)=-2.2s+3.18{\cdot}Log(T_L)\;(r^2=0.99)$. The result in comparison of variations of Z. platypus populations, in lake was more remain to better than in upstream and downstream them. Also the b value, assessed by Length-weight relationship in lake was 3.36, in upstream and downstream were 3.09, 3.15, respectively indicating the fish in lake better than stream. The slopes of population condition controlled by K factor also showed positive relationship. It was higher in lake environment than in stream sample, reflecting that population of Z. platypus distributed in lake Hoengseong was favorable and stable condition. The lake environment seems to be providing more favorable condition for Z. platypus population.