• Korean Journal of Environmental Biology
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• v.31 no.1
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• pp.1-9
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• 2013

In this study, we tried to describe the distribution patterns of marine opportunistic mollusks in Korean waters where various environmental stresses have been imposed. Five opportunistic molluscan species were found from four types of disturbed benthic environments around Korea. Theora fragilis, Macoma incongrua, Musculista senhousia were typical dominant species mainly in the coastal area such as harbour regions and semi-enclosed regions where their sediments were enriched with organic matter and summer hypoxia occurred. However, in the waste dumping areas located in the Yellow Sea and southeastern shelf, small size bivalves such as Thyasira tokunagai and Raetellops pulchella were typical opportunistic species.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.510-524
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• 2022

For the assessment of the benthic community health of Jinhae Bay using the Benthic Pollution Index, macrobenthic fauna samples were seasonally collected from 23 different sites between February, 2011 and November, 2012. The macrobenthic community health status was classified as "Poor" or "Very Poor" except for the bay mouth part of Jinhae Bay at the northern part of Geoje Island. A large proportion of functional Group IV and even azoic conditions appeared due to summer hypoxia at sites in sheltered regions of Jinhae Bay. Some of the dominant species recruited after summer hypoxia were Paraprionospio patiens, Sigambra bassi, and Theora fragilis belong to typical opportunistic species. By comparing the BPI values of the macrobenthic communities from other special management areas of Korea, Jinhae Bay was considered to have the lowest condition that was heavily polluted among special management areas.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.246-253
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• 2011

In this study, we investigated the effect of freshwater discharge on benthic community in Nakdong estuaries. The sediment was dominated by sand except few channels where heterogenetic sediment composition was observed. Sediment composition was rarely affected by freshwater discharge during the rainy season; however, organic content in the sediment slightly increased after the rainy season. Macrobenthic species composition differed spatially. For instance, species composition decreased after the rainy season near the barrage. Benthic community analysis revealed three groups, in which the first group was found between barrage and sand bars located at the mouth of estuary, the second group was observed outside the sand bars, and the last group was found in the channel. Opportunistic benthic species indicative of organic pollution, such as Sinocorophium sinensis, Magelona japonica, and Heteromastus filiformis, dominated areas close to the barrage. Organic pollution by freshwater discharge appears to be responsible for the emergence of opportunistic benthic species, and this influenced areas from the mouth of bay to sand bars. Outside the sand bars, freshwater discharge did not seem to have affected species composition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.262-271
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• 2000

This study was carried out to clarify the spatial and temporal patterns of benthic environments and macrobenthos on the subtidal soft-bottom in Chonsu Bay. Seasonal surface water temperature was similar to the bottom layer, but freshwater discharges into the outlets dereased the surface salinity around the dyke in summer. Bottom dissolved oxygen was decreased deeply around the dyke and created the de-oxygenated layer during summer. Sediment grain size was consisted of finer at the neighboring of the dyke than the mouth of the bay. Organic matters including the sediment were decreased at the mouth of the bay. A total of 311 species ($769\;ind./m^2$) were identified. Polychaetes were the most abundant faunal group in the number of species and densities. The number of species revealed the spatial patterns that it was higher in the mouth of the bay, and their densities showed seasonal changes by mass recruitment occurred at the most of the area in summer, At this time, opportunistic species, Lumbrineris iongifolia and Theora fragilis, were also recruited massively. Chonsu Bay were classified into five station groups by the cluster analysis. The dominant species around the dyke were composed to opportunistic species, those in middle area were Sternaspis scutata, Paraplionospio pinnata, and those in the mouth of the bay were Mediomastus californiensis, Nephtys polybranchia. Seasonal fluctuations and spatial difference of environments seem to have influenced to the species compositions and affected to the stability of benthic ecosystems spatial-temporally In Chonsu nay.

• 주택과사람들
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• s.192
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• pp.68-71
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• 2006

정부는 올해부터 대폭 늘어나는 종부세. 양도세가 강남 집값에 적지 않은 영향을 미칠 것으로 보고 있다. 실제 납세자들이 연말 세금고지서를 받아보고 느낄 보유세 부담은 만만치 않을 것이기 때문이다. 하지만 종부세 회피를 위해 매물 출회 가능성과 양도세 무서워서 못 판다는 지적 등 다양한 반응을 보이고 있는 강남 아파트 시장을 분석해보자.

• The Korean Journal of Ecology
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• v.27 no.3
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• pp.173-177
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• 2004

The number and abundance of epiphytic algae growing on Sargassum thunbergii and their functional forms were examined. Thalli of S. thunbenii were collected on the nine islands of southern coast and at Gyeokpo on the western coast of Korea in summer 2001. A total of 25 species, 6 green (24%), 2 brown (8%), 17 red algae (68%) were identified in the present study. Caulacanthus okamurae, Ulva pertusa, Sphacelaria furcigera were found on the thalli of S. thunbegii that collected at the all regions. Caulacanthus okamurae, Champia bifida and Laurencia venusta grew on the lower parts of S. thunbergii thalli whereas, Polysiphonia spp. attached to the apical parts of the plants. Four functional forms, such as sheet-form (8%), filamentous-form (52%), coarsely branched-form (32%) and articulated-calcareous algal form (8%) were distinguished. The epiphytic algae on the thalli of S. thunbergii are mainly annual opportunistic algae, filamentous-form algae and smaller red algae. Also, most epiphytic seaweeds of S. thunbergii produce and release spores before pseudoperennial host plants are necrotic in late autumn.

• School Mathematics
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• v.12 no.4
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• pp.605-617
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• 2010

This study explores the characteristics and roles of non-textual elements in secondary mathematics textbooks in the United States and South Korea, using a conceptual framework that I have developed: variety, contextuality, and connectivity. Analyzing five U.S. standards-based textbooks and 13 Korean textbooks, this study shows that although non-textual elements in mathematics textbooks are free of literal language, they exhibit different emphases and reflect assumptions about what is important in learning mathematics and how it can be taught and learned in a particular societal context (Mishra, 1999; Zazkis & Gadowsky, 2001). While there are similar patterns in the use of different types of non-textual elements in textbooks from both countries, different opportunities are provided for students to learn mathematics between the two countries.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.227-233
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• 2013

Speceis composition and distribution by altitude of fish in the rock tide pools in Taean were determined using montly samples collected in the 9 tide pools from January to December 2010. Among 16 species collected, a forktongue goby Chaenogobius annularis was dominant accounting for 34.6% in the total number of individuals, and followed by Dictysoma burgeri (22.0%), Sebastes schlegelii (6.9%) and Tridentiger trigonocephalus (6.8%). A resident fish Dictyosoma burger occurred at all tide pools, and Chasmichthys dolichognathus was dominant in the upper tide pools and was collected throughout the study period. The resident fish is more abundant than the transient fish and occasional fish accounted for 61.4%, 14.2% and 24.4% in biomass, respectively.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.304-306
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• 2003

최근 이질적인 네트워크 환경에 적합한 다양한 멀티미디어 데이터를 서비스할 수 있는 연구가 광범위하게 이루어 지고 있다. 따라서 유동적인 네트웍 상황에 맞추어 전송되는 스트리밍 데이터는 사용자에게 보다 우수한 품질의 서비스를 제공받을 수 있는 기회를 준다. 본 논문에서는 대용량의 멀티미디어 데이터를 서비스하는 과정에서 발생하는 스트리밍 데이터의 에러 발생을 최소화할 수 있는 기법인 적응형 FEC 기법을 제안한다. 이 기법은 멀티미디어 데이터의 전송량을 최소화하면서 고화질 영상의 전송을 가능하게 한다.

• School Mathematics
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• v.19 no.2
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• pp.289-317
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• 2017

This study aims to explore how Korean middle-school mathematics textbooks on functions provide students an opportunity-to-learn [OTL]. For this purpose, we investigate 3 textbooks in terms of mathematics content and practice, the level of cognitive demands of mathematical tasks, types of student responses, types of context-based tasks, and connections among the tasks. The findings from the data analysis suggest as follows: a) an opportunity-to-learn to connect procedures to functional concepts and new ideas of functions to the existing one is very limited; b) the textbooks seem to provide students an OTL to understand functions as definitions, rules and conventions and to experience repeatedly procedural executions through worked examples and mathematics tasks; c) students may not experience to explain their own ideas/thinking by using mathematical sentence or justify their own cognitive processes; and d) students can be exposed to get a sense of mathematics as a set of fragmented and isolated facts or procedures, rather than to encourage to expand and deepen their understanding of functions.