• Journal of Wetlands Research
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• v.21 no.3
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• pp.199-206
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• 2019

To understand vegetational characteristics of abandoned paddy terraces (APTs), species composition and plant species richness of APTs were compared with those of other natural- and constructed wetlands (NWs and CWs, respectively). Based on frequency of major vegetational components, Phragmites japonicus was more common in APTs (23.9%) than NWs (10.8%) and CWs (10.8%), whereas P. australis was less frequent in APTs (18.3%) than NWs (43.1%) and CWs (35.4%). Typha orientalis was common only in APTs (19.7%), whereas T. angustifolia was relatively common in NWs (21.5%) and CWs (32.3%). In addition, some wetland obligate species such as Leersia japonica, Oenanthe javanica, and Sium suave were frequently found only in APTs. In particular, APTs showed higher plant species richness ($6.3{\pm}2.2\;species/m^2$) than NWs ($4.9{\pm}1.8\;species/m^2$) and CWs ($3.9{\pm}1.3\;species/m^2$). APTs exhibited not only their distinctive vegetational characteristics but also higher ecological value in terms of plant species richness. Further attention on APTs as valuable biotopes supporting diverse plant species and continuous effort for management and conservation are needed more.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.374-383
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• 2021

In 2020, the diversity of benthic macroinvertebrate communities was investigated in the Sohan stream, an ecological and landscape conservation area, and the results were compared with the previous research conducted in 2011. In total, 42 species (two phyla, three classes, and seven orders) were found in the Sohan stream. Species richness and abundance sharply decreased at all sampling sites because of Typhoons Haishen and Maysak in 2020, which had a direct impact on the stream. In the functional feeding group, the ratio of collector-gatherers was the highest at all sampling sites. However, during the autumn season, the shredder ratio increased from 13.4% to 42.4% in the uppermost stream site. Compared with the diversity of benthic macroinvertebrates surveyed in 2011, a total of 53 species (two phyla, three classes, and eight orders) were found. The percentage of species richness and abundance of Ephemeroptera, Plecoptera, and Trichoptera was more than 50% both in 2011 and 2020. Only the richness of Ephemeroptera was significantly different between them (2011: 2.9 and 2020: 6.7). In this study, the abrupt changes of species richness and abundance in benthic macroinvertebrate were not observed before and after the designation of an ecological and landscape conservation area. However, it is necessary to monitor benthic macroinvertebrates in order to confirm that biodiversity is continuously maintained long after the designation of the ecological and landscape conservation area.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.717-734
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• 1996

For a scalar rational function, the spectral data consisting of zeros and poles with their respective multiplicities uniquely determines the function up to a nonzero multiplicative factor. But due to the richness of the spectral structure of a rational matrix function, reconstruction of a rational matrix function from a given spectral data is not that simple.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.129-135
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• 2009

We investigated the moth diversity on an island of southern sea of Korea. We collected moths at three sites on the island of Bogildo, Wando-gun, Jeonnam using a 22-watt ultraviolet light trap from May to October, 2008, and identified a total of 272 species and 948 individuals in 13 families. Species of Noctuidae was the most abundant, with 107 species and 318 individuals, followed by Geometridae (62 species and 147 individuals) and Pyralidae (53 species and 269 individuals). The graph of the estimated species richness in Chao 1 (432.25$\pm$37.39) did not reach an asymptote, which suggests that more moth species could be identified on the island through further sampling. An arctiid moth, Miltochrista striata, was the most abundant species captured in this study. Monthly changes in moth species richness and abundance formed M-shaped curves, with peaks in early summer (June) and late summer (August). Cluster analysis of seven sites on three islands (Aphaedo Island, Sinan-gun, Oenarodo Island, Goheung-gun and Bogildo Island) divided the sites into two groups. Distances among sites and habitat types may play an important role in determining the similarities of moth faunas among sites.

• Journal of Information Technology Applications and Management
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• v.18 no.4
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• pp.21-40
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• 2011

Emoticons perform an important role as an enhancement to written communication, in areas such as Windows Live Messenger instant messaging, e-mails, mobile Short Message Services (SMS), and others. Emoticons are graphic images used in communications to indicate the feelings of people exchanging messages via mobile technology. In this research, the perceived usefulness of the emoticon in mobile phone text messages is verified with consumers using the five construct model of Huang. A K-means clustering technique for separating three groups based on levels of perceived usefulness of mobile emoticons is used with a structural equation model test using Smart PLS 2.0, and the bootstrap re-sampling procedure. We analyzed relationships among use of emoticons, enjoyment, interaction, information richness, and perceived usefulness. The results show there are relationships among use of emoticons, enjoyment, interaction, perceived usefulness, and information richness, however enjoyment of emoticons did not significantly affect the perceived usefulness of messages with emoticons alone. The results suggest emoticons have different affects on emotion in both mobile, and Messenger contexts. Our study did not consider more detailed media properties, and thus more studies are needed. Our research results contribute to mobile communication activation, provides companies with an understanding of key characteristics of consumers who use emoticons, and provides useful implications for improving management and marketing strategies.

• Journal of Ecology and Environment
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• v.41 no.3
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• pp.99-106
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• 2017

Background: Plants over-expressing Arabidopsis ABF3 (abscisic acid-responsive element-binding factor 3) have enhanced tolerance to various environmental stresses, especially drought. Using terminal restriction fragment length polymorphism (T-RFLP) analysis, we compared the rhizosphere-associated structures of microbial communities for transgenic potato containing this gene and conventional "Jopoong" plants. Results: During a 2-year field experiment, fungal richness, evenness, and diversity varied by year, increasing in 2010 when a moderate water deficit occurred. By contrast, the bacterial richness decreased in 2010 while evenness and diversity were similar in both years. No significant difference was observed in any indices for either sampling time or plant line. Although the composition of the microbial communities (defined as T-RF profiles) changed according to year and sampling time, differences were not significant between the transgenic and control plants. Conclusions: The results in this study suggest that the insertion of ABF3 into potato has no detectable (by current T-RFLP technique) effects on rhizosphere communities, and that any possible influences, if any, can be masked by seasonal or yearly variations.

• The Korean Journal of Ecology
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• v.20 no.6
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• pp.451-459
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• 1997

Seasonal and spatial distribution of vascular plants were examined and related to soil texture, pH, moisture and nutrient contents in the riparian zone of the Balan Stream. In spring the area was dominated by Alopecurus aequalis var. amurensis, was displaced by Persicaria thunbergii and Humulus japonicus in summer. From the stream channel to bank, soil texture and pH were not significantly differentiated, moisture decreased, organic matter and K increased, and TKN and available P increased in June and decreased in August. DCA ordination analysis by species distribution showed spatially and seasonally distinct patterns seasonal difference was evident on axis 1, and spatial difference according to the distance from stream channel was clear, too. Both axis 1 and axis 2 scores were significantly correlated with biomass, pH, and phosphate. Species richness increased were significantly correlated with biomass, pH, and phosphate. Species richness increaed with increasing organic matter and phosphate, and decreased with increasing soil moisture and K. Biomass increased with increasing organic matter, but was negatively related to pH, moisture, TKN, available P and K. Available P was significantly correlated with biomass, pH, and total soil nitrogen. In conclusion, the distribution of riparian vegetation was governed by soil physico-chemical properties, which are primarily determined by how far it is from the stream channel.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.455-466
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• 2014

Seasonal variations in species composition of catches were explored using seasonal samples caught by shrimp beam trawl in the Geum river estuary in 2011. During the study period, total catches were collected 91 species as fish 47 species, crustacean 28 species, mollusca 4 species, gastropoda 5 species, shellfish 3 species and others 4 species. The dominant species were Exopalaemon carinicauda, Eriocheir leptognathus, Palaemon gravieri, Mugil cephalus, Acanthogobius hasta, Cynoglossus joyneri, Pennahia argentata and Coilia nasus. The amount of species in spring and summer was higher than in autumn. The diversity index (H') was 0.43~0.96, evenness index (EI) was 0.14~0.25, and richness index (RI) was 1.54~4.25. Using cluster analysis 91 species were divided into 4 groups. Group I appeared mainly in spring and summer. Group II appeared only in summer. Group III appeared in winter and spring, and Group IV in spring and autumn.

• Journal of Information Technology Services
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• v.13 no.4
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• pp.1-17
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• 2014

Domestic and international energy and eco-friendly companies take advantage of social media for image enhancement and product promotion. However, there were no in-depth empirical analysis to verify specific effectiveness of social media use in these sectors. The purpose of this study is to reveal the key factors that are considered to use social media effectively for energy and eco-friendly companies. For this purpose, we regarded the effectiveness of social media as Post Awareness and Word of Mouth. Characteristics of social media as a medium were measured separately, media richness and media genre, as independent variables of social media effectiveness. We investigated 413 posts in Facebook brand page of energy and eco-friendly companies and conducted a content analysis. As a result, post awareness of users was greater when post has richer media such as video. For media genre, word of mouth appeared to be greater when the posts provide information.

• Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.151-155
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• 2012

We used nine microsatellite DNA markers to estimate genetic variation among wild and cultured populations of the sea squirt Halocynthia roretzi. The loci were polymorphic, with 6-32 alleles, and allelic richness ranged from 6.0 to 26.1 in each population. The wild and the cultured populations had similar mean heterozygosities ($H_O$ and $H_E$), allele numbers, and allelic richness. One cultured population with softness syndrome had a lower mean in the observed heterozygosity ($H_O$ = 0.57) and higher mean inbreeding coefficient ($F_{IS}$ = 0.261) than any other populations. This suggests that the loss of genetic variation in the diseased population might be due to increased inbreeding. A neighbor-joining tree and pairwise population estimates of $F_{ST}$ showed moderate genetic differentiation between the wild and the cultured populations. Additionally, the softness syndrome population was genetically divergent from wild populations, but it was genetically close to the cultured populations.