• Title/Summary/Keyword: multidimensional scaling

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Seasonal variations in species composition of fish assemblage collected by trammel net in coastal waters of the East Sea (동해 연안 자망에서 채집된 어류 종조성의 계절변동)

  • Choi, Kwang Ho;Han, Moon Hee;Kang, Chang-Keun;Park, Joo Myun;Choi, Jung Hwa;Park, Jeong-Ho;Sohn, Myong Ho;Baeck, Gun Wook;Choy, Eun Jung;Lee, Chung Il
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.4
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    • pp.415-427
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    • 2012
  • Seasonal variation in species composition and abundance of fish assemblage in the north coast (NC: Ayajin) and central coast (CC: Hupo) of the East Sea were calculated using samples collected by trammel net during 2011-2012. A total of 20 species from NC and 17 species from CC were collected. Of the fishes collected, the dominant fish species were Glyptocephalus stelleri and Careproctus rastrinus in the NC, and Dasycottus setiger and G. stelleri in the CC. These 2 fishes accounted for 71.7% and 81.0% of the total number of individuals collected in the NC and CC, respectively. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The cluster analysis and non-metric multidimensional scaling (MDS) based on Bray-Curtis similarity revealed that the fish assemblages classified into north and central groups. Analysis of similarity percentages of species contributions (SIMPER) indicated that most individual of G. stelleri and Gadus macrocephalus contributed to north group, and D. setiger and G. stelleri in central group, whereas 15 species contributed to 90% of the dissimilarity.

Characteristics of distribution and community structure of marcrobenthic Invertebrates caught in the coastal waters of middle East Sea, Korea (동해 중부해역 저서무척추동물의 분포특성 및 군집구조)

  • YOON, Byoung-Sun;CHOI, Young-Min;SOHN, Myong-Ho;KIM, Jong-Bin;YANG, Jae-Hyeong;PARK, Jeong-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.4
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    • pp.372-385
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    • 2016
  • This present study investigated characteristics of distribution and community structure of macrobenthic invertebrates through the survey of commercial Danish seine fisheries from 2011 to 2013. In this study, a total of 28 species were sampled with a mean density of $32,568ind./km^2$ and mean biomass of $1,649.5kg/km^2$. The dominant species, comprising over 1.0% of the total number of individuals, were Chionoecetes opilio ($11,203ind./km^2$, 34.4%), Pandalus eous ($9,247ind./km^2$, 28.4%), Ophiuridae spp. ($5,750ind./km^2$, 17.7%), Argis lar ($2,631ind./km^2$, 8.1%), Neocrangon communis ($994ind./km^2$, 3.1%), Berryteuthis magister ($612ind./km^2$, 1.9%), Sepiola birostrata ($499ind./km^2$, 1.5%) and Strongylocentrotidae sp. ($424ind./km^2$, 1.3%). The dominant species, in terms of biomass, comprising over 1.0% of the total biomass, were C. opilio ($1,167.2kg/km^2$, 70.8%), B. magister ($130.3kg/km^2$, 7.9%), P. eous ($102.4kg/km^2$, 6.2%), Ophiuridae spp. ($84.6kg/km^2$, 5.1%), Enteroctopus dofleini ($45.5kg/km^2$, 2.8%), A. lar ($35.7kg/km^2$, 2.2%), Strongylocentrotidae sp. ($25.0kg/km^2$, 1.5%) and S. birostrata ($22.1kg/km^2$, 1.3%). Among them, S. birostrata, E. dofleini, Strongylocentrotidae sp. and Ophiuridae spp. were higher abundance and biomass in the shallow water (<200 meters in depth), whereas C. opilio, P. eous, A. lar, N. communis and B. magister were higher in the deep water (301 ~ 500 meters in depth). As the results of cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, the macrobenthic invertebrates community by Danish seine survey was divided into two groups of station in the shallow water (<200 meters in depth, Group A) and the deep water (201 ~ 500 meters in depth, Group B). The major individual-dominant species was S. birostrata, Ophiuridae spp. and immature C. opilio in group A. But Group B was P. eous, A. lar, B. magister and mature C. opilio.

High School Gifted Students' Perception on Cheating in School (개념도를 통해서 본 고등학교 영재학생의 학업부정행위에 관한 인식)

  • Kim, Sang-Woo;Han, Ki-Soon
    • Journal of Gifted/Talented Education
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    • v.23 no.1
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    • pp.67-87
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    • 2013
  • This study explores high school gifted students' perception of cheating in school using the concept mapping method. The map shows the gifted students' concept structure and the different perception between gifted and non-gifted students on cheating. For the purpose, 63 high school gifted students participated at the brainstorming stage to gather the possible related statements. Finally, 64 statements were confirmed and these were divided and evaluated by 13 focus group students. Then, they were analyzed by multidimensional scaling and processed by hierarchical cluster analysis. The results compiled from this procedure show that high school gifted students' perception of cheating is classified into five clusters: "unacceptable cheating behaviors of friends", "an inseparable relation among social structure, giftedness and cheating", "conflict, coping skills, and tolerance related to the cheating", "immorality in one's inner person" and "the judgement based on morality and social justice". In addition, 150 gifted students and 160 non-gifted students checked the degree of agreement to each statement with the likert 6 points scale and the result showed that there was no significant difference in two clusters, "unacceptable cheating behaviors of friends" and "the judgement based on morality and justice", while it turned out that there were significant perception gaps in three clusters, "inseparable relation among social structure, giftedness and cheating", "conflict, coping skills, and tolerance related to the cheating" and "immorality in one's inner person". Implications of the study related to the gifted students' moral behaviors were discussed in depth.

The Understanding of Retailing Competition Structure (소매점 유통경쟁구조의 이해)

  • Park, Seong-Yong;Shin, Ji-Yong
    • Korean Business Review
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    • v.13
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    • pp.107-132
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    • 2000
  • The entry of large discount stores such as E-mart, LG mart, Magnet etc. into small cities have had a profound impact on the business of small-sized retailers. Now, it becomes the matter of survival for small-sized retailers and it is almost impossible to reverse those trends. Without satisfying consumers' various needs and wants, retailers can not survive. Therefore, it is extremely important to understand retail competition from the perspective of consumers in order for retailers to survive in the turbulent environment. The previous research studies on retail competition have focused on the comparison among different types of retailers with respect to strategic retail mix variables. However, they do not consider the competitive aspects of consumers' sides. In addition, we do not fully understand the meaning of "shopping." Shopping means hedonic shopping as well as utilitarian shopping. Utilitarian aspects are important but consumers also prefer' hedonic aspects too. That is the reason that traditional retailers such as small-sized retailers can not compete with modem and large retailers. We use three different methods to identify the macro and competitive structure. of retailing with respect to shopping. Factor analysis, multidimensional scaling, and multiple correspondence analysis are used to produce perceptual mapping of retail competition. Department store and large discount store are identified as close competitors but both might have an indirect impact on small-sized retailers through demand shift toward high end retailers.

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An Analysis on Perception of Mothers about Career for Elementary Science-Gifted Children (초등과학영재 어머니들의 자녀 진로에 대한 인식 분석)

  • Kwon, Yoon-Ah;Kim, Hyo-Nam
    • Journal of The Korean Association For Science Education
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    • v.37 no.4
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    • pp.577-586
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    • 2017
  • The purpose of this study is to try to structuralize the perception of the mothers of science-gifted elementary students using the concept mapping approach. The mothers who participated in this research had children who were 5th and 6th graders selected as science-gifted by a regional education office, a science high school and two national universities in a city. One of the authors interviewed 26 mothers, and extracted 50 general statements of their perceptions about the career path of their children. Ten mothers who participated in interviews sorted a shuffled pack of statement cards. The categorization of the statements into the dissimilarity matrix was carried out by SPSS multidimensional scaling analysis and hierarchical cluster analysis to generate a conceptual diagram. After that 140 mothers rated each statement using a Likert-type response scale from one to five. The result showed six clusters of parental views such as were 'Burden of private education, grades and going to the next grade,' 'Thinking about career guidance in gifted education and school,' 'Parental roles in child career education,' 'Difficulties in career guidance at home,' 'Demand for strengthening the parental capacity for career guidance,' and 'Demand for social support.' 'Demand for social support' obtained the highest sympathy from mothers of elementary science gifted.

Effects of Habitat Disturbance on Fish Community Structure in a Gravel-Bed Stream, Korea (자갈하천에서 서식처 교란이 어류 군집구조에 미치는 영향)

  • Kim, Seog Hyun;Lee, Wan-Ok;Cho, Kang-Hyun
    • Ecology and Resilient Infrastructure
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    • v.1 no.2
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    • pp.49-60
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    • 2014
  • Fish assemblages play an integral role in stream ecosystem and are influenced by stream environmental conditions and habitat disturbances. Fish community structures and habitat parameters of U.S. EPA rapid bio-assessment protocol were surveyed to investigate the effect of stream environment and habitat disturbance on fish communities at 13 study sites in the Gapyeong Stream, a typical gravel-bed stream. Principal component analysis (PCA) based on data from habitat assessment at each study site indicated that the study sites were differentiated by habitat parameters such as embeddedness, velocity/depth regime and sediment deposition, which were related with bed slope. A total of 46 species belonging to 12 families were collected in the Gapyeong Stream. A dominant species was Zacco koreanus, subdominant species was Z. platypus. Hierarchical cluster analysis based on species abundance classified fish communities into the three main groups along the stream longitudinal change. Non-metric multidimensional scaling (NMDS) portrayed that fish community structures were related to major habitat parameters, i.e., epifaunal substrate/available cover, embeddedness, velocity/depth regime, sediment deposition, channel alternation and frequency of riffles. These results suggested that fish community structures were primary affected by the longitudinal environmental changes, and those were modified by habitat disturbance in the Gapyeong Stream, a gravel-bed stream.

Conceptualizing Caregiving Supports for Families Who Have Children with Disabilities: A Concept Mapping Application (장애아동 가족을 위한 돌봄지원 개념화: 개념도 연구법을 활용하여)

  • Kim, Yu-Ri;Choi, Bogcheon
    • The Journal of the Korea Contents Association
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    • v.17 no.9
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    • pp.498-509
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    • 2017
  • Caregiving supports have been provided to decrease caregiving burdens of families of children with disabilities, but there are needs for improving caregiving services. The purpose of this study was to conceptualize content items and domains of caregiving supports from the perspectives of parents and service providers in order to help families of children with disabilities to decrease their caregiving burdens. This study used concept mapping that was useful for service-needs identification and program development. First, focus group interviews with two parent groups and one service provider group were conducted to generate a total of 31 items. Also, they sorted the items in terms of conceptual similarity and rated the items in terms of their needs. Next, the sorting data were analyzed using multidimensional scaling and cluster analysis and the rating data were calculated for mean. The results provided 31 content items in four domains: regular caregiving, activity-based caregiving, parent empowerment for caregving, and strengthening family relationships. All the domains were rated as important to decrease caregiving burdens. This study has practical implications for improving caregiving services and the related policies.

Effect of Environmental Variables on the Inter- and Subtidal Macrobenthic Communities in the Iwon Dike Area (이원방조제 주변의 조간대 및 조하대 대형저서동물의 군집과 환경요인과의 관계)

  • LEE Jae-Hac;YU Ok Hwan;LEE Hyung-Gon;PARK Ja-Yang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.37 no.4
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    • pp.295-306
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    • 2004
  • Spatial patterns in the macrobenthic community structure in the inter- and subtidal zones in front of the Iwon Dike and environmental variables were examined in August 2001, In total, 156 macrobenthic species(123 intertidal species and 90 subtidal species) were recorded during this study, predominately polychaetes $(40{\%})$, bivalves $(22{\%})$, and crustaceans $(22{\%})$. Polychaetes made up less than $40{\%}$ of the intertidal communitr, but more than $50{\%}$ of the subtidal community. The mean density during this study was $1,456ind./m^{2}.$ Multivariate analysis (multidimensional scaling) revealed significant differences in community structure among four regions: near the Iwon dike (B1), the high and middle intertidal zone (B2), low intertidal zone (Al), and subtidal zone (A2). The number of species, total density, and diversity (H') varied significantly among the four regions. The distribution of macrobenthic community was affected by environmental variables, such as ${\%}$ silt/clay content, total sulfide, lose of ignition, and chemical oxygen demand. These environmental variables were negatively correlated with the dominant species (Nephtys polybranchia, Umbonium thomasi, and Scoloplos armiger) in the intertidal area, but positively correlated with the dominant species (Lumbrineris cruzensis, Notomastus latericeus, and Moerella sp.) in the subtidal area. Environmental variables $({\%}\;silt/clay content and total sulfide)$ were positively correlated with the dominant species (Heteromastus filiformis) in region Bl, but negatively correlated with the dominant species (Umbonium thomasi and Scoloplos koreanus) in region B2. Amphipods Urothoe spp. and Monoculodes koreanus were the dominant species in region Al. Umbonium thomasi, the dominant species in region B2, was not found in regions Bl or Al. We suggest that the inter-specific competition for territory and exposure to seawater may be important factors controlling the macrobenthic community structure in the inter- and subtidal zones in front of the Iwon Dike.

What Kinds of Rearing Stress Do the Mothers of the Gifted Have?: Using a Concept Mapping Approach (영재 자녀를 둔 어머니들의 양육 스트레스 분석: 개념도 기법을 활용하여)

  • Han, Ki-Soon;Lee, Young-Mi
    • Journal of Gifted/Talented Education
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    • v.22 no.4
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    • pp.893-916
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    • 2012
  • This research investigates gifted students' mothers' rearing stress based on the concept mapping method. For this, 12 gifted students' mothers solicited, gathered and analyzed related statements, and then did multidimensional scaling and hierarchical cluster analysis. The stress value was .273 which was appropriate for the two level concept mapping study. In addition 101 mothers of gifted students rated for the rearing stresses they experience. Results were as follows. First, 79 concrete statements were solicited and as a result of concept mapping were categorized as 'burden and conflict as mothers of the gifted', 'possible negative characteristics due to the giftedness', and 'self-esteem and pressure by the title of the gifted'. Especially following items showed relatively high average: worrying about how to give the child a specific help for his/her career(M=4.65); worrying that she might be intervening too much in their child's behaviors(M=4.60); getting pressured supporting the child to get involved in the gifted education system continually(M=4.46); worrying if her child is not developing his/her talent enough due to the lack of time and money(M=4.44); being concerned that her high expectations might be putting her child under too much pressure (M=4.43). Implications of the study related to gifted education practices were discussed.

The Development of a Sampling Instrument for Aquatic Organisms in Rice Paddy Fields: Submerged Funnel Traps with Attractants (논 생태계 서식 수서생물 채집 도구 개발: 유인제를 사용한 수중트랩)

  • Yoon, Sung-Soo;Kim, Myung-Hyun;Choi, Soon-Kun;Eo, Jinu;Kwon, Soon-Ik;Song, Young-Ju
    • Korean Journal of Environmental Biology
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    • v.35 no.4
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    • pp.640-647
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    • 2017
  • The need for an efficient sampling technique to collect aquatic organisms has risen with the increase of interest in rice paddy fields, which have been recognized as important ecosystems supporting biodiversity. In the present study, a submerged funnel trap used with the assistance of attracting agents (fish meal and chemical light) was designed as an easy, objective and quantitative tool for collecting aquatic organisms in the rice paddy fields. The preference for collecting aquatic organisms as a means for attracting agents was analyzed using a generalized linear mixed model. Also, based on the data of previous research, we compared the community composition of the aquatic macroinvertebrates, which were collected using the quadrat method, and newly designed submerged funnel traps, by analyzing non-metric multidimensional scaling. The results showed that the catching efficiency of 18 of the total 65 taxa was affected by the attracting agents. 12 taxa including Pomacea canaliculata, Hippeutis cantori, Austropeplea ollula, Erpobdella lineata, Ostracoda spp. Branchinella kugenumaensis, Hydaticus grammicus, Rhantus pulverosus, Chironomidae spp., Rana nigromaculata, Cobitidae spp. etc., favored fish meal and 6 taxa including Ischnura asiatica, Coenagrionidae spp. Sternolophus rufipes etc., were attracted by chemical light. The submerged funnel trap used as a measurement tool for biodiversity was less applicable than the quadrat method; however, it was more effective for the selective collection of specific taxa. We expect that this newly designed trap can be a simple and quantitative method for collecting aquatic organisms, and could be used for long term and extensive surveys in rice paddy fields in the future.