• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.663-675
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• 2019

During the last decade, the dominant design of display has been LCD, and it has been led by Korean manufacturers. However, their leading positions has been recently threatened by Chinese manufacturers, Korean manufacturers are endeavoring to move toward next generation display technologies. They embarked on standards battle to win dominant design especially in the next generation display market for TVs by launching new technologies such as Quantum-dot display and OLED. While there are a number of factors of dominant design, it is expected that the technical attributes of the technology itself may be the most significant factor. For this reason, this research scrutinizes consumer preferences for technical attributes, and attempts to provide implications for standards battle in the display (for the TVs) sector. For this purpose, we employed a conjoint analysis for the preferences of potential consumers. The results show that potential consumers prefer displays with higher resolution, natural color, and durabillity.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.275-285
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• 2017

To investigate the changes of dominant species of benthic macroinvertebrates according to the changes of temperature and precipitation, we surveyed twenty sites of the main Seomjin River in May and September in 2013 and 2014. The temperature, precipitation, water quality factors and substrate composition, which are important factors in benthos habitat environment, were collected and measured. The average temperature of the Seomjin River increased by $0.2^{\circ}C$ in 2014 compared to 2013, and the temperature increased from upstream to downstream, showing a difference of more than $3^{\circ}C$. Also, the annual cumulative precipitation (ACP) was increased toward low latitude. The temperature of Seomjin River increased more than twice in September ($21.7{\sim}24.5^{\circ}C$) after rainfall compared to May ($7.6{\sim}11.3^{\circ}C$) before rainfall, and CP (cumulative precipitation) increased about 3 times before rainfall (263 mm~287.5 mm) and after rainfall (756.3 mm~882 mm). Due to washing effect by summer precipitation, total number of species and individuals for benthic macroinvertebrates were higher in May than in September. Chironomidae sp. and Choroterpes altioculus were dominated in May, Ecdyonurus levis, Macrostemum radiatum and Choroterpes altioculus were dominated in September. As a result of correlation analysis between community indices and environment factors, it was found that there is a high correlation with boulder and sand among substrate compositions. According to the results of cluster analysis based on temperature, CP and the dominant species of benthic macroinvertebrates in Seomjin River, it was divided into two groups following temperature and CP, and the dominant species and geographical position were reflected and divided into detailed groups.

• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.240-247
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• 2015

This study was carried out to provide the preliminary data for study of zooplankton community structures and coastal pelagic ecosystem by understanding the seasonal change of zooplankton community depending on environmental factors at Dangdong bay in Tongyeong city. In this study, the environmental factors and the change of zooplankton community were analyzed for 2008 to 2011. In the results, a total of 80 species of zooplankton was sampled with a mean density of $1,599inds.m^{-3}$. The dominant species changed seasonally, and the most dominant species was Acartia steueri in winter and spring, Penilia avirostris in summer, and Evadne nordmanni in autumn. The Canonical Correspondence Analysis was conducted between the major dominant species and environmental factors. And for the environmental factors that effect the zooplankton community, the high correlation was observed with the water temperature, COD, DO and T-N, though there was slight difference among species. Therefore, more various research and environmental study are necessary to understand of planktonic ecosystem because the zooplankton community is affected by the interaction of both physical and biological factors.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.46-54
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• 2020

Artificial and natural changes such as weir construction and climate change often cause abnormal blooming of organism. Therefore, variations in species community of organisms have been actively investigated to identify influential environmental changes on the fresh water ecosystem. In this study, we investigated Chironomidae community and environmental factors at 5 representative weirs (Ipo, IP; Sejong, SJ; Juksan, JS; Gangjeong-goryung, GG; and Dalsung weir) in 4 Korean major rivers to figure out relationship between Chironomidae community and environmental factors. Environmental factors indicating organic matter (total organic carbon, TOC and Chlorophyll-a, Chl-a) showed lower concentration in IP and SJ compared with other sites(JS, GG and DS). 3 sub-family 18 genus 25 species of Chironomidae community were found in this study. Among them, Chironominae was dominant in JS (Tanytarsus sp.1), GG (Polypedilum scalaenum) and DS (Polypedilum scalaenum), while different sub-family were dominant in IP (Orthcladinae, Tokunagayusurika akamushi) and SJ (Tanypodinae, Tanypus punctipennis). Moreover, based on the dominant species of Chironomidae community and environmental factors, the cluster analysis classified our study sites into 3 groups. These results imply that the diet resource is the most important factor for dominance of Chironomidae in Korean rivers. We also suggest that further study on the identification of diet resources for each Chironomidae specie is required for better understating of distribution in species community of Chironomidae at various ecosystems.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.236-244
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• 1990

To improve the prognosis of mitral valve replacement surgery, analysis and evaluation of pre and intra operative risk factors will be very much valuable. Author studied 205 cases of mitral valve replacement from Feb 1982 to June 1989 for the risk factors of hospital death. 90 patients were male and 115 were female, and age was from 16 to 59 years, Mitral stenosis dominant lesions were 91 cases and regurgitation 114. Suspected risk factors were NYHA functional class, cardiothoracic ratio, implanted valve type and size, operation time, age and sex, thrombus in left atrium, atrial fibrillation, aortic cross clamping time, left ventricular end diastolic and systolic dimension, nephropathy, hepatopathy and respiratory insufficiency. Statistic analysis was performed by X2 test between survivors and death group. Statistical significances as pre and intraoperative risk factors of hospital death after mitral valve replacement were confirmed in those presence of AF on the EKG, NYHA functional class[>IV], cardiothoracic ratio[>70%], and implanted valve size[>33mm]

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.210-224
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• 2007

Fish community study by a gill net in four coastal waters of Southern Sea, Korea were simultaneously conducted to determine seasonal variation of species composition and abundance from March to November, 2006. A total of 68 species and 577,422.9 g by four study waters were caught during the survey period. The dominant species were Platycephalus indicus, Mugil cephalus, Cynoglossus robustus and Argyrosomus argentatus of 58.2% in total catch and they occupied 63.1% in IRD (index of relative distribution). By regional community, fishes that compromised 18 species and 53,148.8 g in Tongyeong Donam were caught and the dominant species were Platycephalus indicus, Hexagrammos otakii, Liparis tessellatus, Paralichthys olivaceus. In Yeosu Gyedong, fishes of 44species and 123,926.9 g were caught and the dominant species were Platycephalus indicus, Muraenesox cinereus. In Jangheung Sumoon, fishes of 44 species and 123,926.9 g were caught and the dominant species were Mugil cephalus, Platycephalus indicus, Cynoglossus robustus, Liparis tessellatus. And in Jindo Modo, fishes of 32 species and 171,426.3 g were caught and the dominant species were Platycephalus indicus, Argyrosomus argentatus, Cynoglossus robustus. Therefore, the species composition and abundance of fish by region were very different. These results seem to be related to differences of regional environmental condition, productivity, and fish ecological habits. And the fish catch in four study waters were high from April to July, and the number of fish species and diversity index had a tendency to increased from March to November. The ranges of environmental factors caught fish were $8.3{\sim}28.5^{\circ}C$ in temperature, 26.59~34.92 in salinity and also these factors were correlated to seasonal variation of fish.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.62-71
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• 2020

Understanding vegetation structure and the relationship with environmental factors has been crucial for restoration and conservation of riparian zones. In this study, we conducted field survey in a riparian zone of Namhan River in South Korea both before and after flooding in order to understand temporal and spatial variations of riparian vegetation. There were significant temporal and spatial variations in species composition, and distribution patterns of vegetation were different along a gradient of elevation above the water level. At low elevation, Zizania latifolia was dominant throughout the field survey periods, and Bidens frondosa began to grow late and dominated both in post-flooding 1 and 2. Prior to flooding, Scirpus radicans and Polygonum thunbergii were widely distributed at middle elevation, while Artemisia vulgaris, Phragmites australis, and Miscanthus sacchariflorus were dominant at high elevation. After flooding, P. thunbergii was dominant at middle elevation with most other species decreasing, and more invasive or pioneer plants, including Artemisia princeps, H. scandens, and Sicyos angulatus, were observed at high elevation. Species composition and distribution patterns were homogeneous at low elevation, whereas dynamic variations of vegetation were observed both temporally and spatially at higher elevations. Elevation and distance from the water front were the most principal factors governing vegetation structure. Furthermore, soil physicochemical properties were also found to determine species composition and distribution patterns. These results indicate that vegetation structure in the riparian zones is formed by the combined effects of hydrological regime and soil physicochemical properties, inherent characteristics of species, and interspecific competition. Understanding of temporal and spatial variations of riparian vegetation may provide useful insights into ecological restoration and conservation of the vegetation within the riparian zones.

• The Korean journal of sports medicine
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• v.36 no.4
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• pp.180-188
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• 2018

Purpose: The purpose of this study is to identify bilateral differences of physeal closure of the lateral compartment of the elbow in osteochondritis dissecans (OCD) and related factors with premature physeal closure. Methods: Initial radiographs of the bilateral elbows in 40 baseball players with OCD (group I) were reviewed for the status of physeal closure of the lateral compartment; capitellum, radial head, lateral epicondyle. Forty baseball players with medial epicondylar apophysitis (group II) were enrolled as a control. Relative status of physeal closure of dominant elbow was defined as early, same, and delayed. Bilateral differences of the status of physeal closure were analyzed between groups, and according to the radiographic stages, extent of the lesions and demographic factors in group I. Results: Significant early physeal closures of dominant elbows were identified in group I in capitellum (group I, 55%; group II, 3%), radial head (group I, 53%; group II, 3%), and lateral epicondyle (group I 37%; group II, 5%). In group I, advanced stage and extended lesion showed early lateral compartment physeal closure especially in capitellum and radial head, and players with longer career length and limitation of motion showed early closure. Conclusion: Over the half of the adolescent baseball players with OCD demonstrated early radiocapitellar physeal closures of dominant elbow in initial presentation. Because premature physeal closure contributes to the development of arthritis without appropriate radiocapitellar remodeling, early detection of OCD is essential for prevention of arthritis and successful conservative management.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.1-6
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• 1989

The occurrence of thyroid disorders is connected with iodine deficiency, defective synthesis or releasing of thyroid hormone and endemicity. Genetic factors are known as a single gene defects, interaction of multiple genes with environmental factors, as well as chromosomal aberrations. Diofnosis thyroid disorders is enforced by I-131 uptake test, thyroid scanning with I-131 or Tc-99 m and serum radioimmunoassays of T3, T4, free T4 and TSH. They were largely classified as hypothyroidism, hyperthyroidism, simple goiter and normal. The pedigree of 58 families was drawn by propositus, and then the correlation between thyroid disorders and TSH levels was analyzed. The results are as follows: 1) The offsprings and their mothers of 15 families were hypothyroidism, THS level was 5 folds for offsprings and 4 folds for mothers in comparison with control group. 2) 13 families were hyperthyyroidism in siblings but their mothers were normal in thyroid function, TSH level of the siblings was lower than control group. 3) Though the offsprings and their mothers of 10 families were similar to TSH level of control group, they are all simple goiter, familial thyroid disorders, in other thyroid function test. The familial thyroid disorders suggested that these transmitted from mothers to offsprings with X-linked dominant or autosomal dominant inheritance.

• Computers and Concrete
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• v.19 no.1
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• pp.111-120
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• 2017

This study aimed to design the accelerated life testing (ALT) of concrete, which stimulating the special natural environment maximumly. Its evaluation indexes, such as dynamic elastic modulus, mass and ultrasonic velocity were measured, and the variation of relative mass and relative dynamic elastic modulus of concrete were studied. Meanwhile, the microanalysis method was used. Moreover, an exploratory application of the stochastic approach, the Weibull distribution and the lognormal distribution, were made to assess the durability of concrete structures. The results show that the ALT for simulating natural environment is more close to the service process of concrete structure under actual conditions; The relative dynamic elastic modulus can be used as the dominant durability evaluation parameters, because it is more sensitive to the environmental factors compared with the relative quality evaluation parameters; In the course of the concrete deterioration, the destruction of the salt freezing cycle is the dominant factor, supplemented by other factors; Both of those two stochastic approaches can be used to evaluate the reliability of concrete specimens under the condition of ALT; By comparison, The lognormal distribution method is better to describe the reliability process.