• Weed & Turfgrass Science
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• v.3 no.2
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• pp.95-101
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• 2014

This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weed species and the degree of damages caused by those weeds occurred in cultivated Ligularia fischeri fields. Survey was carried out five times, on May, June, July, August and October in 2013. The weed flora was composed of a total of 104 weeds, 37 families, of which 55 species were annual, 25 species were biennial, and 24 were perennial plants. Twenty-six exotic species were included as well. Dominance was the highest with Chenopodium album followed by Stellaria aquatica, Echiochloa crus-galli, Conyza canadensis, and Artemisia princeps etc. in order. In the PCA plot analysis, weeds occurred in cultivated L. fischeri fields were divided into three groups, Persicaria thunbergii-Bidens frondosa community, Chenopodium album community and Capsella bursapastoris community. The degree of damages in cultivated L. fischeri fields was investigated by weighing roots of L. fischeri. We found that 56% decreased root weight in no weeding plots comparing to that in weed management plots. We infer from this result that decreased roots will affect to the growing of L. fischeri in following year.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.190-198
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• 2010

This study was conducted to examine the effects of dams on benthic macroinvertebrate communities in Korean streams and rivers. Four low-head dams and three large dams were studied throughout South Korea. Sampling was taken at immediately upper (impoundment), lower (riffle area), and control (riffle area) sites from the dams during 2004-2007. The upper sites, of which substrate heterogeneity and velocity were relatively low, showed a lower degree of species richness, density, and diversity indices, which is very different from the lower and control sites. Heavily polluted streams showed a lesser degree of community differences between the upper and lower sites. In the large dams, the upper and lower sites showed very low values of species diversity indices and very high values of dominance indices compared to the control sites. In the low-head dams, however, the difference of degree of the values was relatively smaller. Compositions of the functional feeding groups and the habitat orientation groups were relatively simpler at the upper sites than at the lower sites and the degree of difference was greater in the large dams. Species richness and community indices of benthic macroinvertebrates were more significantly affected by habitat characteristics than water quality at the upper sites; however, those were more significantly related with water quality at the lower sites. In conclusion, large and low-head dams could simplify stream habitats particularly at the upper sites (impoundment), and they negatively affected on the benthic macroinvertebrate communities inhabited the habitats. The impact was larger in the large dams than in the low-head dams.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.105-115
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• 2017

The present study is to understand the Bongseonsa stream in the National Arboretum fish fauna variation through comparison with historical data and to evaluate the stream health situated. We performed investigations over three times from April to September 2015. In the survey, 2,960 individuals which belonging to 22 species, 8 families were collected. Dominant species by number was Zacco platypus and subdominant species was Zacco koreanus. Seven Korean endemic species (Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Koreocobitis rotundicausata, etc) were observed and showed a ratio of 36.4%. The community analysis revealed that the structure of fish community in the study sampling sites was instability in having dominance 0.79 (${\pm}0.15$), diverse 1.21 (${\pm}0.60$), evenness 0.58 (${\pm}0.15$) and species richness 1.49 (${\pm}0.83$). The values in the Qualitative Habitat Evaluation Index (QHEI) was averagely 122.9 (${\pm}44.8$) in the Bongseonsa stream and this was showed to have favorable habitat surroundings. As a result of tolerance guild analysis, the total number of sensitive species and intermediate species were higher than tolerant species. Analysis was divided into A and B two groups of fiducial 12.25% in Cluster analysis degree of similarity between study sampling sites. Fish Assessment Index (FAI) was rated A and B grade in Bongseonsa stream that stream health showed favorable. However Wangsuk stream as a urban stream rated C grade and analysed the lowest grade in the whole study sampling sites. There was high correlation beteween FAI and various indexes, dominance, diverse, evenness and sensitive species and intermediate species.

• Korean Journal of Environment and Ecology
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• v.31 no.4
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• pp.409-419
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• 2017

Although Korean red pine (Pinus densiflora) forests near temples are valuable as forests of the cultural landscape, they are likely to be deteriorated because of vegetation succession and climate changes. The purpose of this study is to investigate the vegetation structure, the pine vitality, and the site environmental characteristics of the pine forests near temples to identify the correlation between pine tree growth and location environment. We selected Chuneunsa, Wonhyosa, Jeungsimsa, and Taeansa Temples since these four areas still had the healthy pine forests. In all four studied area, the pine trees dominate the canopy layers while the deciduous broadleaf trees mostly inhabited appeared in the lower layers. The growth of pine trees in Jeungsimsa and Wonhyosa areas was not as good as Chuneunsa area where the pine trees tended to be older. We found higher total nitrogen content in soil in Jeungsimsa area than other areas, maybe because of increase in total nitrogen caused by the development of low vegetation in the area. This peculiarity may have led to the pine trees in the area to fall behind the deciduous broadleaf trees in competition for nitrogen nutrient and thus to show deteriorated growth. The altitude and the twig length showed a negative correlation as did the degree of slope and the mean importance percentage of the pine tree. In other words, the growth environment such as soil became poorer when the altitude and the degree of slope increased, and thus the growth amount and dominance of the pine trees were lower. The degree of slope showed a positive correlation with the twig length of the pine tree. Within boundaries of location environment where the pine tree forests were dominant, it seemed that growth of the pine trees was more favorable as the slope was steeper because the trees could avoid competition with deciduous broadleaf trees. On the other hand, the growth of pine trees deteriorated as the electrical conductivity of soil increased; increase in soil nutrients might have accelerated vegetation development of deciduous broadleaf trees and thus aggravated the growth environment of pine trees to negatively affect maintaining the health of the pine tree forests.

• Journal of Families and Better Life
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• v.2 no.1
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• pp.93-109
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• 1984

The purpose of this study is to investigate the direction and strategy of education for sex role concepts of children on the basis of factor analysis of the present situation in sex role concepts and their formation. Although some maintain that sex role concept of our society has been changing slowly, the traditional sex role concept still dominates and is potentially immanent. the analysis of present condition of our society indicates that the formal as well as informal education are facing with various crucial problems in providing the direction of behavior demanded for carrying out the role. The close analysis of the three theories, psychoanalytic theory , social learning theory, cognitive development theory, lends a support to the laim of the study that cognitive development theory provide an integrated frame of reference for us to see the sex role education analytically Furthermore, the factors which are found to have influences on the formation of sex role have been analyzed in three areas: Family, School and society. 1)The factors in family such as parental behavior of upbringing and their concepts of sex role have a direct relationship with the nature of sex tole concept of children. Therefore, the first step to make children to habe a new type of sex-role conception appropriate for modern societies is to change that of parental conception and attitudes. 2)the quantitative as well as the qualitative aspects of school education showed no exceptional trend from the dominant conception of the society, although school are expected to lead the society as formal education institution rather than just reflect the society. The educational activities and contents such as the conceived goal of education for eoch sex, textbook constitation, teaching behavior and sex-role concepts of teacher are found to be still dominated by the traditional sex-role assumption. 3) The social factors that have direct relationship with children's sex-role formation are social and cultural, which include social milieu, condition of employment, family structure and mass-media. Since family and school do not educate the young in a social vacuum. their educational function of sex-role formation are doomed to be limited and determined by these social factors. Unfortunately, the analysis of present conditions showed the dominance of traditional types of sex-role concepts in all these social factors. The education of sex-role concept for children should be treated as one of the most crucial value problems related with many other important problems, such as direction and patterns of behaviors of each sex, the degree of self-development and capabilities, and consequently human right, equality, humanization and the quality of happiness. Neverthless, the analysis of researches on sex-role education which have been surveyed in this study lead to a conclusion that concerted effort to change the education, formal as well as informal should be provided in every aspect of social life. If the sex role education of the past has aimed at the "feminization"of girls which indoctrinate girls into a limited and fixed role of house wives, the new education in the future should be directed foward "humanization" of both sexes which opens the diversity of roles for both boys and girl on equal levels and provide future possibilities in accordance to their individual capabilities and interests.

• Computers and Concrete
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• v.32 no.3
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• pp.287-302
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• 2023

Corrosion of reinforcing bars in reinforced concrete structures due to chloride attack in environments containing chloride ions is one of the most important factors in the destruction of concrete structures. According to the abundant reports that the corrosion rate around the repair area has increased due to the macro-cell current known as the incipient anode, it is necessary to understand the effective parameters. The main objective of this paper is to investigate the effect of the kinetic parameters of corrosion including the cathodic Tafel slope, exchange current density, and equilibrium potential in repair materials on the total corrosion rate and maximum corrosion rate in the patch repair system. With the numerical simulation of the patch repair system and concerning the effect of parameters such as electromotive force (substrate concrete activity level), length of repair area, and resistivity of substrate and repair concrete, and with constant other parameters, the sensitivity of the macro-cell current caused by changes in the kinetic parameters of corrosion of the repairing materials has been investigated. The results show that the maximum effect on the macro-cell current values occurred with the change of cathodic Tafel slope, and the effect change of exchange current density and the equilibrium potential is almost the same. In the low repair extant and low resistivity of the repairing materials, with the increase in the electromotive force (degree of substrate concrete activity) of the patch repair system, the sensitivity of the total corrosion current reduces with the reduction in the cathode Tafel slope. The overall corrosion current will be very sensitive to changes in the kinetic parameters of corrosion. The change in the cathodic Tafel slope from 0.16 to 0.12 V/dec and in 300 mV the electromotive force will translate into an increase of 200% of the total corrosion current. While the percentage of this change in currency density and equilibrium potential is 53 and 43 percent, respectively. Moreover, by increasing the electro-motive force, the sensitivity of the total corrosion current decreases or becomes constant. The maximum corrosion does not change significantly based on the modification of the corrosion kinetic parameters and the modification will not affect the maximum corrosion in the repair system. Given that the macro-cell current in addition to the repair geometry is influenced by the sections of reactions of cathodic, anodic, and ohmic drop in repair and base concrete materials, in different parameters depending on the dominance of each section, the sensitivity of the total current and maximum corrosion in each scenario will be different.

• Journal of the Korean Regional Science Association
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• v.6 no.2
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• pp.123-147
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• 1990

This paper examines the changing geography of producer service industries in the 1980s. The foci of this study are to analyze the regional distribution of each producer services, and to reveal the spatial linkage of producer services. Further this paper asserts the potential role of producer services for reducing the potential endogenous development in the periphery. During the 1981-86 period, producer service industries grew more rapidly than other service sectors and manufacturing sector. The main reason of the raid growth of producer services is attributable to an increase in demand for intermediate services from manufacturing firms. In order to compete an increasingly complex business environment, firms have expanded the amount of effort devoted to activities such as planning, coordination and control, and consequently have increased their use of producer services. The most distinctive feature of the location of producer services is spatial concentration into Seoul and surrounding region. Especially the degree of the concentration o business services into the Capital Region has been accelerating during the 1990s. The pattern of employment growth and regional distribution of producer services show a clear core / periphery disparity. Much of the regional inequality in producer services is largely due to variation in demand associated with the pattern of corporation headquarters with the pattern of corporation headquarters and branch plants location with large manufacturing firms. The analysis of spatial division of labor reflects that producer services are related to the location of headquarters in manufacturing industry. Headquarters in manufacturing firms and business service firms tend to cluster each other. Most of the headquarters spatially separated from branch offices are clustered heavily in Seoul. Especially headquarters of business services and insurance services are overwhelmingly concentrated into Seoul. The firms whose headquarters are located in Seoul have a linkage pattern on a nationwide scale. It is viewed have little potential for generating local multiplier effects and regional development. In the light of the result of this study, producer services are not likely to disperse soon to peripheral regions. Consequently the absence of policies directed at enhancing producer sevice in the periphery, concentration tendency would continue to reinforce the core's dominance at the expense of peripheral regions. From a regional perspective, the quality of a region's producer service sector is a key determinant of economic growth, since manu industrial location decisions are influenced by the differential availability of producer services among regions. Poor performance of producer services in peripheral regions seemed to be linked to the region's manufacturing base. Low-wage, standardized branch plants are not likely to induce the growth in knowledge intensive services associated with high-technology corporate headquarters. Producer services may help to create and attract new business including manufacturing firms, and also to enhance the productivity and competitiveness of local firms. Therefore the provision of service producing activities would be lead not only to generate and retain endogenous development but also to attract external firms, especially small and medium sized firms which have a lower propensity of internalized services. Hence, it may be more efficient to create and expanse new locally owned producer services rather than to attract branch plants of mult-locational firms in order to make indigenous economic development.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.70-82
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• 2007

Aiming at nature's early restoring needs to select plant species harmonizing with surrounding environment that fits to restoring goal of ultimately aiming at woody plants dominant vegetation that protect and stabilize surface parts of bared slopes. And it is important to make it assimilated with surrounding natural vegetation by differentiating planning of seed mixtures. Natural Ecological Restoring Construction Methods (JSB Method) was developed to increase the effect of landscape change according to seasons not to simple hydro-seeding by reducing rate of foreign grasses while raising rate of wild flower using. It was considered that using wild flowers that bloom on each season solved the problems of slope landscapes that looks artificial and uninteresting. After researching environmental condition of the slopes, JSB Method has shown that, as of wet-type method, soil is relatively soft and the difference of thickness of plant base soil media affects on the difference of soil hardness. In case of soil hardness of 8.8~17mm, there's dangerousness of slope's collapsing, but it has shown that growth of plant was favorable. For the acidity of soil, most of them are in the type of neutralized soil of more than pH 6. And after analyzing the degree of woody plants dominance, it had shown that lower part was occupied with wild flowers and other herbaceous species like China pin, golden phesant mum, pitcher plant, and middle and upper part was occupied with woody plants like silk-tree, sumac forming multi-layer structure. It can be concluded that the restoration objects of the woody plant vegetation on the roadside slopes can be accomplished successfully by Natural Ecological Restoring Construction Method (JSB method).

• Journal of Forest and Environmental Science
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• v.16 no.1
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• pp.1-16
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• 2000

This study was carried out to examine the process of plant succession through vegetation invasion and to select appropriate endemic plant species for rapid stabilization and good visual effect on cut-slopes of forest roads. Establishing total of sixty $1m{\times}1m$ sample plots. fifteen for each forest road constructed in the year of '93 (six-year-old), '95(four-year-old), '97(two-year-old), and '98(one-year-old), the ecological attributes of invading vegetation on cut-slopes were analyzed. The results are summarized as follows: 1. The rate of vegetation coverage was highly associated with soil hardness and aspect of cut-slope. Higher rate of vegetation coverage was caused by larger number of invading plant species. 2. The dominant woody species were Rubus crataegifolius, Rhus chinensis, Lespedeza bicolor, Salix hulteni, Alnus hirsuta, and Pinus densiflora. The visual attractive for the fruit of Rubus crataegifolius and the autumn coloration of Rhus chinensis was noteworthy. The dominant herbaceous species were Youngia sonchifolia, Spodiopogon sibiricus, and Lysimachia clethroides in all study forest roads. Spring flower of Potentilla freyniana and Viola rossii: summer flower of Lysimachia clethroides, Commelina communis, Glycine soja. Persicaria sieboldi, and Oenothera odorata: and autumn flower of Artemisia stolonifera and Impatiens textori were abundant and remarkable. 3. The diversity index of woody species tended to be increased as years passed after construction, and that of herbaceous species were decreased. 4. The dominance of Th of dormancy form was early high in the first year of construction, getting decreased thereafter. And that of MM + M + N was increased as years passed after construction. but that of Ch+H+G+Th+HH was decreased. 5. The degrees of succession were estimated by 359, 111, 97, and 87 for the construction year of '93, '95, '97, and '98. respectively, increased as years passed after construction.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.87-100
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• 2016

This research was performed for the purpose of providing useful and base data and preservation strategy of growth characteristics of Rhododendron micranthum. From the result of research, wild growth area of Rhododendron micranthum was discovered near steep forest road on 695~901m in altitude above sea level of Baekdu-daegan National Arboretum. Vegetation colony structure of Site I was resulted in Pinus densiflora(tree stratum M.I.P.=45.3%) is dominants, Betula schmidtii(arborescent M.I.P.=9.8%) is second dominant, and Site III resulted in Pinus densiflora(tree stratum M.I.P.=30.5%) is dominants, Betula schmidtii(arborescent M.I.P.=10.3%) is second dominant. Site II resulted in Betula schmidtii(arborescent M.I.P.=30.4%) is dominants and Pinus densiflora tree(tree stratum M.I.P.=8.3%) is second dominants. For herbs, it was researched that the rate of one year herb of chrysanthemum family(10), rice family(3), sedge(2) was higher than near forest area. Among Species diversity index, that of Shannon was in range of 0.7348~1.1090. After comparing this with similar area, this value was relatively low. Dominance analysis result was analyzed that various groups are evenly distributed. Monthly highest average temperature is $23.9^{\circ}$ in Site A and Site B, and monthly lowest average temperature is $-4.5^{\circ}C$ in Site I and $-4.7^{\circ}C$ in Site II. Monthly maximum average humidity is 85.6% in Site I and 83.2% in Site II. Monthly minimum average humidity is 60.9% in Site I and 60.8% in Site II and it showed that these 2 area are located far away but have similar temperature and humidity characteristic and climate environment is similar. It was analyzed that humidity is high with the result of annual average humidity is over 60%. In growth characteristic, it showed that doubt damage of Stephanitis pyrioides, exposure of roots, peeled bark was discovered and supplement on this is urgent.