• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.301-310
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• 2008

This study was to analyze characteristics of fish compositions and longitudinal distribution, based on trophic and tolerance guild at 22 sampling sites of Yeongsan River watershed during 2003$\sim$2006, and also to compare before and after the estuary dam construction. The collected fishes, based on catch per unit effort (CPUE), were 44 species in the watershed and dominant fishes were Zacco platypus, Acheilognathus macropeterus, Zacco temminckii and Carassius auratus. According to comparative analysis of fish in the non polluted sites (NPS) vs. polluted sites (PS), the number of species and individuals was lower by 70% in the PS than the NPS, indicating ecological degradations by chemical pollutions or/and habitat modifications. The relative abundance of sensitive and insectivore species decreased as the stream order increases, while tolerant and omnivore species increased with the stream order. In this survey, largemouth bass (Micropterus salmoides), which is a top-carnivore and exotic species, may influence trophic guild system throughout active predations on endemic species, resulting in modifications of ecological functions. The construction of estuary dam on Yeongsan River in 1981 resulted in wider lacustrine zone and desalinated through limitation of seawater input. These physical changes have caused increases of lentic dwelling species and limited fish migrations (i.e., eel). Overall, fish fauna and composition analyses showed that the number of species and individuals in this water body may be reduced due to inputs of pollutants from the watershed, habitat modifications, and increases of exotic species (largemouth bass). For these reasons, effective lake management strategies are required for the ecosystem conservation.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.421-428
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Pohang Old Harbor and Pohang New Port, etc. due to construction of New Port in Youngil Bay. This type of trial might be a milestone for port development in macroscale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.529-542
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• 1987

Thirty three species belonging to twenty genera in the subfamily Gobiinae of Korea were reviewed and key to species and genera were provided. Among them twenty seven species captured during 1985-1987 were examined on the cephalic sensory canal systems for the taxonomic review, and classified into 4 groups based on the presence or absence of the canal and their canal pore patterns. It was confirmed that the pore patterns of preopercular and anterior ocular-scapular canal were important in the diagnosis of gobiid genera or species and in the discussion of the specialized species group. It was considered that the genus of Acentrogobius masago should be transferred to Pseudogobius from Acentrogobius, because A. masago was more similar to P. jausnicus than to A. pflaumi and its congeneric species in their cephalicc sensory canal systems. Some populations of Chaenogobius annularis and Acanthogobius lactipes showed the geographical variations in cephalic pit organs and the number of predorsal scales. The endemic gobiid species was not found the Korean waters, but some species showed a disjunct distributions between the west and the east coast waters in Korea. The south coast was inhabited by the abundant species including twenty seven species of seventeen genera. The genera of Acanthogobius, Chaenogobius, and Chasmichthys were considered to be the common genera in Korean waters.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.360-367
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• 2010

The genetic diversity and structure of P. tongkangensis in 5 populations from 3 regions was investigated using 56 markers derived from 6 ISSR primers. Genetic diversity at the species level (P=94.6, SI=0.377, h=0.240) was substantial considering the limited distribution and small size of populations. Genetic differentiation among regions (12%) and among populations (13%) in the region was not clearly evident, which suggested a moderate level of gene flow among adjacent populations. The Mantel test revealed a significant correlation between genetic differentiation (${\Phi}_{ST}$) and geographic distance among populations. This was supported by cluster analysis and principal coordinate analysis (PCoA). The significant difference in marker band frequency at many loci and their fixation in opposite directions in the smallest and most isolated population SC were considered due to genetic drift. Therefore, the genetic diversity of P. tongkangensis could be compromised if the distribution area or the size of the population was further reduced. In particular, small and isolated populations could be at great risk of extinction. Considering this, the unique habitats of P. tongkangensis should be protected and the reduction of population size should be closely monitored. Conservation efforts including the seeding and planting of seedlings should be done carefully based on their genetic and ecological traits. Our data support the argument that establishing an integrated management system for the efficient conservation of P. tongkangensis is critical.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.167-172
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• 2000

Inter-simple sequence repeat (I-SSR) markers were analyzed from diploid genomes of 95 nutmeg trees (Torreya nucifera Siev. et Zucc.) in 5 populations. A total of 62 I-SSR amplicons were observed and 7 of them were monomorphic in 95 individuals. DNA fingerprint of each tree was verified by pooling the observed I-SSR amplicons. Most of the genetic diversity was allocated within population (90.65%) and all the populations revealed similar level of I-SSR amplicon diversity within population. Degree of population differentiation (${\phi}_{ST}=9.35%$) was moderate on the basis of criteria obtained from isozyme analysis. Based on the results of the cluster analysis of UPGMA, genetic relationships among 5 populations were not coincided with the pattern of geographic distribution. Non-significant confidence interval at each node also suggests that all the nutmeg populations are genetically not much differentiated.

• Korean Journal of Ichthyology
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• v.21 no.2
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• pp.76-80
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• 2009

Genetic diversity and genetic structure within the Geum River and Mankyung River populations of the Korean endangered Black shinner (Pseudopungtungia nigra) were assessed by amplified fragment length polymorphism (AFLP). AFLP analysis using five primer combinations generated 447 AFLP bands with 64.1% polymorphism (Geum River 74.6% and Mankyung River 53.6%). The heterozygosities within the two populations were calculated to be 0.170 and 0.104, respectively. Their average genetic diversities are 0.240 and 0.147, respectively. The pairwise Fst value (0.150) indicated distinct genetic differentiation between the two populations. A UPGMA dendrogram based on genetic distance among the individuals revealed a division corresponding to geographical regions, with low genetic variation within the Mankyung River population, and low genetic distance (0.026) between the two populations. Consequently, the two populations may have the same genetic origin The Geum River population will be more suitable than the Mankyung River population for conservation plans to increase the population sizes. Genetic and habitat management will be necessary for the Mankyung River population.

• Animal Systematics, Evolution and Diversity
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• v.18 no.1
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• pp.13-21
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• 2002

To add genetic information to the conservation efforts on grey coral (Naemorhedus caudatus) in Korea, we investigated the pattern of mitochondrial cytochrome b gene sequence (606 bp) of six specimens from two localities in Korea. The corresponding sequences of N. caudatus in China obtained from GenBank were also used. The nucleotide Tamura-Nei distances between each of four haplotypes of N. caudatus in Korea and the haplotype of N. caudatus in China varied from 0.0650 to 0.0803: N. caudatus revealed high level of sequence diversity in Bovidae. In N. caudatus in Korea, the distances among three haplotypes at Yanggu were 0.0151 to 0.0185, and it suggests that the genetic diversity of Yanggu population was decreased in low level. Moreover, the distances between each of three haplotypes at Yanggu and one haplotype at Samcheok were 0.0343 to 0.0489. It indicates that habitat isolation caused the continuous increase of genetic distance with geographic distance in N. caudatus, and various conservation plans for mitigating the loss of genetic diversity in Korea have to be in immediate action. To clarify the taxonomic status of N. caudatus, the sequence (276 bp) of N. goral available from GenBank were also utilized, and n goral was not distinct from N. caudatus. It suggests that they may be conspecific, but further analyses with additional specimens of two species are necessary.

• Journal of Life Science
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• v.26 no.8
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• pp.881-886
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• 2016

Cephalanthera erecta (Thunb. ex, Murray) is an herbaceous and a member of the genus Cephalanthera in the family Orchidaceae. The species is an herbaceous and has reputed Chinese medicinal value. It has been investigated the population density and spatial distribution of this species at Mt. Ahop in Korea during 2015. The spatial pattern of C. erecta was analyzed according to several patchiness indexes, population uniformity or aggregation under different sizes of plots by dispersion indices, and spatial autocorrelation. The mean crowding (M*) and patchiness index (PAI) showed positive values except one small plot (2 m × 2 m). Most natural individuals of C. erecta for plots were not uniformly distributed in the forest community. The small plots (2 m × 2 m, to 8 m × 16 m) of C. erecta were uniformly distributed in the forest community and large plots (16 m × 16 m and 16 m × 32 m) were aggregately distributed. Significant aggregations by Moran's I of C. erecta were partially observed within IV classes (12 m). Dissimilarity among pairs of individuals could found by more than 18.0 m. In conclusion, the geographic distribution of C. erecta is not even with varying degrees of size of plots and human activities give rise to density effects in the plots at Mt. Ahop in Korea.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.51-58
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• 2014

Genetic diversity and genetic structures were estimated in seven natural populations of Phellodendron amurense Rupr in South Korea using ISSR markers. The average of polymorphic loci per primer and the proportion of polymorphic loci per population were 4.5 and 78.8% respectively with total 27 polymorphic loci from 6 ISSR primers. The Shannon's diversity index(I) was 0.421 and the expected heterozygosity($H_e$) was 0.285, which was similar to the heterozygosity (hs =0.287) inferred by Bayesian method. In AMOVA, 7.6% of total genetic variation in the populations was resulted from the genetic difference among populations and the other 92.4% was resulted from the difference among individuals within populations. Genetic differentiation(${\theta}^{II}$) and inbreeding coefficient(f) for total population were estimated to be 0.066 and 0.479 by Bayesian method respectively. In Bayesian clustering analysis, seven populations were assigned into three groups. This result was similar to the results of genetic relationships by UPGMA and PCA. The first group included Hwachoen, Gapyeong, Bongpyeong and Yongpyeong population, and the second included two populations in Sancheong region. Muju population was discretely assigned into the third group in spite of the geographically short distance from the Sancheong region. There was no significant correlation between genetic relationship and geographic distribution among populations in Mantel's test. For conservation of the phellodendron trees, it would be effective to consider the findings resulted from this study with ecological traits and life histories of this species.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.79-86
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• 2012

An economic ship routing means to sail a ship with a goal of minimizing the fuel consumption by utilizing weather forecast information, and various such systems have been recently studied. For a successful economic ship routing system, an efficient algorithm is needed to search an optimal geographical path, and most of the previous systems were approaching to that problem through a minimal static-cost path search algorithm based on the Dijkstra algorithm. To apply that kind of search algorithm, the cost of every edge assigned with the estimated fuel consumption should be constant. However, that assumption is not practical at all considering that the actual fuel consumption is determined by the weather condition when the ship will pass the edge. To overcome such a limitation, we propose a new optimal ship routing system based on a minimal dynamic-cost path search algorithm by properly modifying the Dijkstra algorithm. In addition, we propose a method which efficiently reduces the search space by using the $A^*$ algorithm to decrease the running time. We compared our system with the shortest path-based sailing method over ten testing routes and observed that the former reduced the estimated fuel consumption than the latter by 2.36% on average and the maximum 4.82% with little difference of estimated time of arrival.