• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.564-571
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• 2011

In order to establish fundamental data for stream restoration and environmental flow, we investigated fish fauna, community and physical habitat conditions in the Dal Stream of Han River Basin. Field monitoring including fish sampling was conducted from September 2008 to October 2009. A total number of fish caught in the 5 sites was 2,080 representing 9 families 35 species, and 19 species (54.3%) including Acheilognathus koreensis and Iksookimia koreensis were Korean endemic species during the study period. The most frequently found species in number was pale chub (Zacco platypus, 25.7%, n = 632) followed by Coreoleuciscus splendidus (18.0%, n = 375) and Z. koreanus (13.0%, n = 272). The lower reach of Dal Stream was more abundance of species, high diversity, evenness and richness, and lower dominance index than those of the upper reach. According to the dendrogram established at 0.63 level of similarity rate, sampling stations were divided into 2 groups. Most of upper streams in Korea consist of riffles and runs that are repeatedly followed by another one. However, stream channelization and leveling have caused reduction of habitat diversity. Therefore, it is necessary to make an effort on stream rehabilitation with evaluation of physical habitat condition by indicator species in order to maintain biodiversity and perform ecological restoration.

• Journal of the Korean association of regional geographers
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• v.12 no.6
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• pp.645-655
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• 2006

Apsan, as part of the main ecosystem of Daegu city, plays an important role for maintaining the environmental sustainability of the large city. Especially varieties of valuable resources, which are cultural, historical, biological, geomorphological and geological, are distributed around Apsan. Therefore the positive preservation plan is required. This paper aims to examine the environmental characteristics of Apsan and then suggests the following ideas for the environmental preservation and sustainable use of Apsan. 1) 'The New Map of Apsan' that includes more exact information needs to be produced. 2) The Apsan ecosystem management plan should be made under the precision natural ecology investigation. 3) For the protection of inanimate object resources, such as geographical feature and geology, the Geotourism Department needs to be established within Daegu metropolitan office of education or the tourism division of Daegu city government. 4) An effective environmental-impact-assessment system should be officially established. 5) the positive administrative and financial support system led by local NGOs is required for the Apsan environmental protection activities and education. 6) It is necessary to bring out into the open prayer sites to prevent forest fire. 7) 'The nature rest year system' enforcement is required to restore the damaged ecological space of Apsan.

• Steel and Composite Structures
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• v.34 no.5
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• Korean Journal of Medicinal Crop Science
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• v.6 no.1
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• pp.51-56
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• 1998

This study was carried out to evaluate environmental and ecological characteristics of natural habitat for cultivation of Epimedium koreanum. Habitat of E. koreanum was the slope foot of mountain descending gradually toward mostly northwest from top of mountain with slope of $2{\sim}20%$ and the altitude ranged from 60 to 400m above the sea level. Some physiochemical characteristics of habitat soil were as follows: pH, $4.1{\sim}5.8$, organic matters content, $4.9{\sim}6.6%$ and cation exchange capacity, $14.8{\sim}34.3\;me/100g$ soil, respectively. Habitats were shaded by deciduous broad-leaved tree mainly, and compared with those of naked area, relative photon flux density was $3.5{\sim}13.1%$ and relative luminance was $3.3{\sim}11.9%$ due to shading. Air temperature of habitat under shade was $4.3{\sim}6.5^{\circ}C$ lower than that of naked area. Habitat soil temperature was lower than that of naked area but temperature range was smaller than that of naked area. E. koreanum plants were growing with semishading plants under shade of tree leaf. From investigation of natural characteristics of habitat, it was concluded that E. koreanum plant would grow at place with a little change in temperature and moisture of soil which was caused by shading and mulching with litterfall of broad-leaved tree.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.79-90
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• 1994

Water samples were taken at 6 stations from the mouth of Keum River to Kogunsan Archipelago of West Sea during December, 1991 to August, 1992, to determine the distribution of heterotrophic bacteria, their biovolumes and heterotrophic activities. Heterotrophic marine bacteria ranged from $1.0\;{\times}\;10^3to\;5\;{\times}\;10^5c.f.u.$ /ml. As for morphological distribution measured by epifluorescence microscopy, rod-shaped bacteria were between 45% and 72% of all cells during investigation period. Average biovolume of sampled bacteria ranged from $(7.69\;{\pm}\;0.18)\;{\times}10^{-2}to\;(8.18\;{\pm}\;0.38)\;{\times}\;10^{-2}\;{\mu}m^3$ for coccoid bacteria, and from $(6.09\;{\pm}\;0.29)\;{\times}10^{-2}to\;(7.72\;{\pm}\;0.41)\;{\times}\;10^{-2}\;{\mu}m^3$ for rod-shaped ones. The activities of extracellular enzymes ranged from 0.01 to 2.6 ${\mu}M$ /l /hr for glucosidase, from 0.01 to 2.6 ${\mu}M$ /l /hr for amylase, from 0.01 to 8.86 ${\mu}M$ /I /hr phosphatase and from 0.01 to 0.94 ${\mu}M$ /l /hr for chitinase. Extracellular enzyme activities were higher in summer season than in other sampling periods, and phosphatase showed the highest activity among measured extracellular enzymes. Bacterial distribution and their extracellular enzyme activities were associated with water temperature and organic nutrients, but bacterial cell volumes showed no direct relationship with extracellular enzyme activities.

• Korean journal of applied entomology
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• v.20 no.2 s.47
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• pp.98-102
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• 1981

For the investigation of seasonal fluctuation of immature (lavae and pupae) beanfly, infestation rates, and habit, several soybean-cultivars were planted at Kumgok Experiment Farm of KAERI by three different planting times at 25-day intervals. Infestation rates of beanflies were ranged from $85\%\;to\;100\%$ in accordance. with the planting dates, where an increase in infestation rate was found with delay in planting dates. Immature beanflies were already observed from lune 20 by plant dissection counts. Three peaks of the seasonal fluctuation of lava were shown by occurring on July 10, August 10 and 50 during the soybean cultivation, while two peaks of pupal appearances were found. The most high peaks of lavae and pupae occurred on August 10 and 30, respectively. The lava were habitable in the pith or cortex tissue of soybean stem. They prepared tiny hole on the axilla as well as the internode of stem, and then they pupated in the holes from which the adults are able to escape. Immature beanfly seemed to prefer invading to the underground part of the stem when the soybean plants were in young stage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.101-109
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• 1997

The present study was carried out to investigate the temporal and spatial changes in species composition and abundance of polychaetes in Lake Shihwa. Macrobenthic fauna were collected from eight sampling surveys performed in March, June, September and December of 1994, March and October of 1995, February and August of 1996, using a modified van Veen grab with 0.1 $m^2$ coverage area. Polychaete worms, the most abundant macrofaunal group, comprised of 1~22 species at each investigation; number of species continuously decreased during the survey period. The mean density of polychaete was $794{\pm}1,275\;indiv.{\cdot}m^{-2}$ and showed a large fluctuation over time. The variation in abundance was mainly coupled with the domination of Polydora ligni occupying 83% in total density. The next dominant species were Pseudopolydora kempi (mean density of 31 $indiv.{\cdot}m^{-2}$) and Capitella capitata (mean density of 23 $indiv.{\cdot}m^{-2}$). Abundant polychaetes in Lake Shihwa are known to be tolerant to sediment pollution. Ecological indices such as diversity (H') and dominance (D) also indicated that the number of species significantly decreased and a few species predominated in Lake Shihwa after the dike construction. The azoic zone were extended from the upper reach of Lake Shihwa to the vicinity of the dike over time. The reduced number of species, predominance of pollution indicator species and development of an azoic zone reflect severe deterioration of benthic environments in Lake Shihwa.

• Hwankyungkyoyuk
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• v.22 no.2
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• pp.43-55
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• 2009

The objective of this study is to find out the professionalism of secondary school teachers in teaching environmental subjects. This research was conducted using a questionnaire survey of 431 secondary school teachers from 34 schools in Seoul and Gyeonggi Province, Korea. A 5-point Likert scale self-evaluation questionnaire on their professionalism in environmental education was developed based on Hungerford et al.'s (1994) evaluation criteria. Two middle school teachers' classes were observed, and video taping and interviewing were also conducted. The survey analysis revealed that teachers evaluated their professionalism on environmental subjects to be a little above the middle of the scale. The mean values were 2.80 for the foundation level; 2.86 for the conceptual awareness level; 2.84 for the investigation level; 2.94 for the environmental action skills level; and 2.84 for the educational application level. However, class observations revealed that there was some gap between their self-evaluation of professionalism and their actual classroom application. Both classes were not that satisfactory with regard to 'the abilities to communicate and apply ecological concepts', 'the ability to clarify the roles of different value systems for environmental issues and personal values in decision making', 'the ability to clarify their own value system regarding solutions to environmental issues', and 'the ability to apply citizen action skills for solving environmental issues and for sustainable development'. The results provide a basic reference for the improvement of environmental-related education.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.875-901
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• 2017

Although some skeptical views arguing that the impact of organic farming is quite limited to sustainable biodiversity, the organic agriculture has been generally accepted to have positive effects on various properties of soils not only on biophysical and ecological properties but also on biodiversity of the field. Therefore, this field investigation has been conducted to examine the effect of organic farming, relative to conventional agriculture, through a comparative investigations of the two systems for conserving local biodiversity of invertebrate animals. For this research, organic and conventional farming locations matched with both of a paddy field and a upland fields in Goesan-gun province (Chungcheongbuk-do, South Korea) were selected to compare the species richness of invertebrate biodiversity as follows: location OP (Organic Paddy field), location OU (Organic Upland field), location CP (Conventional Paddy field), and location CU (Conventional Upland field). Among 249 species collected, the numbers of species collected in the locations practicing organic farming were greater than the locations practicing conventional farming both in paddy fields (104 vs. 84 species) and upland fields (108 vs. 77 species). Changes in species richness can be shown in the selected locations depending on the agriculture system with organic (50 species) or conventional (44 species) farming systems in the paddy fields, similarly with organic (42 species) or conventional (35 species) farming in the upland fields, respectively. Our present research clearly shows that a wide range of taxa, including insects, spiders and other invertebrates, benefit from organic management through increases in abundance or species richness. It has been also identified that four orders (Hemiptera, Diptera, Hynemoptera, and Araneae) that are largely intrinsic to organic paddy field, and another three orders (Hemiptera, Coleoptera, and Araneae) that are particularly beneficial for organic crop field regime.

• Weed & Turfgrass Science
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• v.7 no.2
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• pp.87-97
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• 2018

Turfgrass provides various beneficial effects to our societies such as recreation, aesthetic components, and other public service. Diseases in turfgrass is the major issue, which cause quality problems in golf courses, playgrounds, parks and cultivation areas, and tremendous cost is required to prevent the diseases. Research activity and investigation for turfgrass disease remain to be further attributed when compared to other crops in Korea. In this study, we present previously reported turfgrass diseases researches, especially caused by fungal pathogens, and review the history of turfgrass research activity in Korea to contribute future turfgrass research direction. Research papers were searched and analyzed using Korea Educational and Research Information Service (www.riss.kr). More than eighty papers presented turfgrass diseases and among the papers, 50% were published in Korean Journal of Turfgrass. Half of the papers reported turfgrass diseases control. Research articles about large patch disease were the majority (36%), followed dollar spot (18%), Pythium blight (10%) and Typhular blight (8%). Number of the first disease reports in Korea were total fifteen. Total 542 fungicides have been registered in Korea to prevent turfgrass diseases and most of the fungicides were for brown patch, rust, yellow patch, dollar spot, snow mold, summer patch, anthracnose, Pythium blight, powdery mildew and algae. And we will also need to conduct ecological studies on turf diseases and to develop control methods with improved efficacy and environmentally-friend sound. Researches on epidemiology of turfgrass diseases which deals with the incidence, distribution, and interactions with other factors will be also greatly favored for precise control prescription, timing of control and use of less pesticides.