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Seasonal Variations in Populations of Small Fishes Concentrated in Shoalgrass and Turtlegrass (Shoalgrass와 turtlegrass에 棲息하는 小型魚類 個體群들의 季節的 變動에 관한 硏究)

  • Huh, Sung-Hoi
    • 한국해양학회지
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    • v.19 no.1
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    • pp.44-55
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    • 1984
  • Abundances of small fishes that utilized seagrass meadows of Redfish Bay, Texas, were analyzed quantitatively to determine monthly changes of this concentrated subtropical fish community during 1982-1983. an effective quantitative sampler, a 1-㎡ thrown cage, yielded a total of 10,223 fishes that comprised 40 species in 23 families, with average total densities about 15 fishes/㎡ in shoalgrass meadow and 6 fishes/㎡ in turtlegrass meadow. The darter goby, pinfish, code goby, and Gulf pipefish were the four most abundant species, and accounted for approximately 85% of the number of fish collected. However, the two different meadows had different relative abundances of fishes. The darter goby numerically dominated shallower shoalgrass meadow, while the pinfish and code goby were the commonest fishes in deeper turtlegrass meadow. Seasonal changes in both species composition and abundances of fish populations were major characteristics in these subtropical seagrass medows. Peak abundance of total fishes occurred during spring, with a secondary peak in fall. Lowest abundance of total fishes occurred in winter. Each abundant species showed its own seasonal abundance pattern, and had a peak abundance 1-3 months separated from other species, with some overlap of increased larval recruitment. Such distinct seasonal abundance patterns with different times of peak recruitment. Such distinct seasonal abundance patterns with different times of peak recruitment among fish species seem to permit use of the seagrass habitats with reduced, seasonal competition.

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The Effect of Invasive Cricket Species, Gryllus bimaculatus on the Survival of Korean Cricket Species, Teleogryllus emma (외래종 쌍별귀뚜라미(Gryllus bimaculatus)가 토착종 왕귀뚜라미(Teleogryllus emma)의 생존율에 미치는 영향)

  • Lee, Eunaa;Kwon, Ohseok
    • Korean Journal of Ecology and Environment
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    • v.46 no.1
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    • pp.67-74
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    • 2013
  • This research was conducted to investigate the competition for survival between the two cricket species: Gryllus bimaculatus (GB) and Teleogryllus emma (TE). The test insects for this research were bred in the greenhouse of the Ecological Entomology Lab, College of Agriculture and Biosciences, Kyungpook National University, Korea. The feeding environment was $28^{\circ}C$ to $30^{\circ}C$, Long-Day condition (16L : 8D) and Relative Humidity: 50%~60%. The changes of the individual number in two species (TE, GB) were checked every day. This research had three experimental conditions which the ratios of individuals (TE : GB) were set at 1 : 2, 1 : 1 and 2 : 1. The survival rate of GB was net better than that of TE in the result of this study. However, due to the absence of the diapauses period in the egg stage, GB would dominate over TE in the field condition. The appropriate legal measure against GB is recommended.

A Research on Development Measures of Information Services for Construction Technology (건설기술 정보서비스 구축 방안에 관한 연구)

  • Ok, Hyun;Kim, Jin-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.8
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    • pp.5707-5715
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    • 2015
  • Recently, construction industry has won an increasing number of orders for overseas construction projects, thereby achieving an external growth, but its competiveness is concentrated on the construction execution field. In particular, the plant field occupies most of the entire orders, which are concentrated regionally in the Middle East and Asia. In addition, low-cost orders are frequently caused by excessive competition. But its high value-added construction engineering(Below, CE) field's overseas market share and technological capacity are very low. Also, technological competiveness, in terms of order amount and other factors, is deepening in polarization between large CE companies and small and medium-sized CE firms. It is noted that the existing CE information systems mostly simply accumulate data such as design and specification standards and provide the information thereon to users, and thus have yet to provide the information essential for the CE and support such efforts. This study sought to prepare a system designed for sharing outstanding design documents information necessary for the CE industry, by category of construction so as to support the technological enhancement of the CE field. Toward that end, this study presented measures for constructing the system and services designed to exchange and share the outstanding design documents information and know-how by construction category necessary between ordering agencies and CE companies.

The Paradox of the Plankton (플랑크톤 패러독스)

  • Lee, Hak Young;Moon, Sung-Gi;Huh, Man-Kyu
    • Journal of Life Science
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    • v.25 no.5
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    • pp.601-606
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    • 2015
  • Hutchinson (1961) proposed that the large number of species in most plankton communities is remarkable in review of the competitive exclusion principle, which suggests that in homogeneous, well-mixed environments species that compete for the same resources cannot coexist. The principle of competitive exclusion would lead us to conclude that only a few species could coexist in such circumstances. Nevertheless, numerous competing species in most natural habitats are able to coexist, while generally only few resources (niches) limit these communities. It is coined “the paradox of plankton” by Hutchinson. We reviewed some literature of the proposed solutions and give a brief overview of the mechanisms proposed so far. The proposed mechanisms that we discuss mainly include spatial and temporal heterogeneity in physical and biological environment, externally imposed or self-generated spatial segregation, horizontal mesoscale turbulence of ocean characterized by coherent vortices, oscillation and chaos generated by several internal and external causes, stable coexistence and compensatory dynamic under fluctuating temperature in resource competition, and finally the role of toxin-producing phytoplankton in maintaining the coexistence and biodiversity of the overall plankton populations. Especially we sited Roy and Chattopadhyay’s reviews and their toxin-producing hypothesis by phytoplankton. This review may be some information to study plankton communities and effect to put the solutions to the paradox that have been proposed over the years into perspective.

Democratization, Marketization and Media Union Movements in South Korea (한국의 민주화, 시장화와 언론노조운동)

  • Shin, Kwang-Yeong
    • Korean journal of communication and information
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    • v.57
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    • pp.69-83
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    • 2012
  • This paper attempts to explore the development of the media labor movement and its tasks. Due to the unique characteristics of information delivered by media, the media labor movement under the authoritarian regime was oppressed and regulated by the government. As democratization has proceeded, the state's oppression and regulation of media has been weakened. However, media workers should wage the struggle for union recognition and independence of editorship simultaneously. Because media unions as labor market organizations also seek for job security and wage increase, we need to understand both political dimension and economic dimension of union activities in media industry. While state's control over media has been diminished in the late 1900s, competition in media industry has been intensified. As small number of media corporations monopolizes the media market, the ecology of media has been completely transformed. Unions in media industry should respond to the change of the media ecology and should build solidarity among media workers at the same time. The achievement of the public nature of media as a part of democratization and building union federation of media industry as a response to the marketization of media still remain as an epochal task for media unions. Like the case of "Hope Bus" in the strike in Hanjin Heavy Industrial Corporation, solidarity between citizens and striking workers should be strengthened.

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Interplays among Public Opinion, Public Policy and Discourse: Case Study about the Discursive Structure and Media Politics Surrounding the Fiscal Soundness Policy (재정건전성 담론 해체하기: 미디어담론에 내포된 프레임 구조와 변화를 중심으로)

  • Kang, Kuk-Jin;Kim, Sung-Hae
    • Korean journal of communication and information
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    • v.63
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    • pp.5-25
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    • 2013
  • Korean society suffers from severe divisions represented by bi-polarization and collapse of the middle class. Intensive demanding on expanding social welfare budget has emerged in accordance with such a dramatic shift. Social consensus moving toward well-financed welfare policy, however, happens to meet political opposition supported by the discourse of fiscal soundness. This paper thus pays particular attention to deciphering the discursive structure in way of understanding how discourses bring public policy into play. For this purpose, news articles about fiscal soundness collected from 8 national newspapers have been analyzed in terms of frame, attitude, perspective and world view. Research results show, first of all, that there exist persistent competition between two frames identified as 'reduced tax with fiscal discipline' and 'increased tax with welfare money.' While the 'reduced tax' frame favors in maintaining tax cut at the expense of welfare budjet, the frame of 'increased tax' supports such arguments as the flexible employment of fiscal soundness and prosperity of national community helped by widening tax revenues. Also did these frames include a number of sub-frames like welfare populism, partisan politics, trickle down effect, tax bonanza for the rich, universal welfare and market over-reactions in order to bolster its logical authority. Media's active taking a part in penetrating supportive frames in line with political stance was found as well. Taking into account both the discursive structure upheld by frames and politics materialized by the media, the authors argue that public policies should be considered more as discourse than fixed reality. Shedding additional light on understanding the interplay among public opinion, policies and media discourse is of another importance for further study.

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School Life of the Freshmen Selected by Admissions Officers Screening (입학사정관 전형 신입생의 학교생활에 관한 연구)

  • Jun, Kyung-Ae
    • The Journal of the Korea Contents Association
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    • v.12 no.6
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    • pp.508-517
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    • 2012
  • Admissions officer system was introduced in an effort to reject the score-oriented competition and select students on the basis of their individual potential and capacity. The admissions officer system, which was first introduced into the college entrance examination for the 2008 school year in Korea, has been operated by expanding the recruiting level up to 11.8% of the number of the students to be admitted by all colleges. The aim of this study is to analyze the performance of the admissions officer system by analyzing the true picture of school life led by the students singled out through admissions officer screening, and further to inquire into the substantial plan to support the students, who were selected through the admissions officer system, for their successful college life while displaying their potential and capacity As a result of doing research on this, it was found that the freshmen selected through admissions officer screening showed more positive responses in all measurement variables this study selected, such as school adaptability, school satisfaction, and career maturity, learning attitude than other students screened in a different way; in addition, school adaptability and school satisfaction came out as significantly high variables statistically. However, they showed insufficiency in the attitude in class from the behavioral aspect in learning attitude. This study made a suggestion that it's necessary for systematic support and management program to be mapped out and provided in order for the students selected through admissions officer screening to improve their learning attitude as they inspire themselves with school adaptability and school satisfaction.

Present Distribution of Cryophilous Plants and Palaeoenvironment in the Korean Peninsula (한반도 한지선호식물의 분포와 고환경)

  • Kong, Woo-seok
    • The Korean Journal of Quaternary Research
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    • v.5 no.1
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    • pp.1-13
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    • 1991
  • The distribution of cryophilous arctic-alpine and alpine plants in Korea is reviewed in connection with palaeoenvironment, along with a discussion to their origins, patterns of migration, and their refugia. At present, the estimated number of Korean arctic-alpine and alpine species is 419, and this includes 75 arctic-alpine species, 239 alpine species and 105 Korean endemic alpine species. The disjunctive distribution of cryophilous arctic-alpine and alpine plants is likely to be due to first, the downslope and southward expansion of those species towards the Korean peninsula as a primary refugia from the arctic region as the Pleistocene glacial phases approached, and then their subsequent isolation upslope in mountain areas toward a secondary refugia as the interglacial and post-glacial climatic ameliorations followed; secondly, the expansion of forest tree communities on lowland and montane areas subsequent to the end of the Pleistocene has had the effect of dividing formerly high mountains as a result of the increased competition; and thirdly, the general disapperance or restriction of available habitats for arctic-alpine and alpine species because of post-glacial climatic amelioration. The existence of 139 alpine species exclusively in the north of Korea may be due to the following reasons; first, frequent exchanges of alpine floras with other neighbouring East Asian regions would have been facilitated; secondly, there are numerous high mountains available for the alpine plants to survive and prosper during the post-glacial period; thirdly, the existence of easy accesses between mountains within the north, which has enabled alpine floras to migrate when necessary; and finally, the availability of diverse environments and habitats for the alpine flora of the north. However, the continued survival of those species in Korea at the world's or East Asia's southernmost limits of their distribution for many species is in danger if global warming associated with the greenhouse effect takes place.

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Vegetation Structure of the Torreya Nucifera Stand in Korea (한반도 비자나무림의 식생구조)

  • Shin, Hyun-Cheol;Lee, Kwang-Soo;Park, Nam-Chang;Jung, Su-Young
    • Journal of Korean Society of Forest Science
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    • v.99 no.3
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    • pp.312-322
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    • 2010
  • In Korea, Torreya nucifera (L.) Siebold & Zuccarini is widely distributed in the warm temperate zone of South coastal area and Jeju island, mainly as preserved forest in the vicinity of the Buddhist temple and Confucian temple. The objective of this study is in order to develop the conservation method and comprehension of vegetation community by current vegetation structure analysis of Torreya nucifera stand. As the results, the number of surveyed species in Torreya nucifera stand were total 148 species with 28 species of tree layer, 38 species of subtree layer, and 82 species of shrub layer. The appearance of the common species were Ligustrum obtusifolium Siebold & Zucc., Hedera rhombea Bean, and Trachelospermum asiaticum Nakai var. asiaticum. All the story of the surveyed region, Torreya nucifera maintained the current dominant species, but the subtree layer and shrub layer was decreased dominant rate because of the development of the crown of tree layer and biased growth of the subtree layer. Most of the tree layer and subtree layer in Torreya nucifera stands are composed of the sprout forest. Therefore, these results suggest that in order to maintain the healthy stand it is demanded for the application of selection thinning method for reducing crown competition in Torreya nucifera forests.

Analysis regarding Complaints of Courier Consumers and Workers in the Parcel Delivery Service by using Topic Model (토픽모델을 활용한 택배 서비스 소비자와 종사자의 불만 사항 분석)

  • Shin, Jin Gyu
    • Journal of Convergence for Information Technology
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    • v.10 no.2
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    • pp.39-48
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    • 2020
  • Many studies have been conducted to analyze factors that affect customer satisfaction, and service quality improvement in the parcel delivery industry. Most of these studies have a limited number of respondents using methods such as surveys and interviews. Therefore, this study aims to supplement the shortcomings of previous studies, by searching and analyzing the common major topics related to the complaints pointed out by consumers and suppliers in the parcel delivery service with cases of consumer counseling, and articles that reflect the complaints of workers in the industry. In addition, by analyzing the trend of these topics, we attempted to discover new topics and suggest implications. In conclusion, topics such as delay/lost/wrong deliveries as well as the fierce competition in the parcel delivery industry, turned out to be central aspects. As a result of the topic trend analysis, talks with international couriers have recently increased, and many conflicts related to apartment parcel delivery have been dealt with. The topics presented in this study are mainly focused on the contents of previous studies, but we expect that new and valuable topics can be derived by adding other data and analysis methods, such as internal counseling and academic literature.