• Journal of Industrial Convergence
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• v.2 no.1
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• pp.73-89
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• 2004

This study uses theoretical perspectives and models from organizational ecology to examine the dynamics and viability of strategic groups. Integrating the ecological perspective and the contingency theoretical view of strategic management, this study developed propositions demonstrating the impact of environmental density and variation on the effectiveness of strategic groups. Justifications for linking ecological perspectives to strategic management theory are discussed and the importance of the integrative approach to strategic management is highlighted.

• The Korean Journal of Ecology
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• v.27 no.1
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• pp.35-41
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• 2004

Phragmites australis is the dominant and constructive species among plant communities in the wetlands of the downstream of Yellow River, China. Its morphological characters were high variable in different habitats. Studies on Morphological and RAPD variation of 15 P. australis populations from this region showed that soil salinity was the dominant ecological factor that affected the morphological characters of P. australis. The basal diameter, height, leaf length, leaf width, internode length, internode accounts, panicle length were negatively related to salinity. 194 loci were amplified by RAPD, of which 9 loci was highly negative-related to salinity, and showed a tendency to prefer the habitats with fresh water. 4 loci were positively related to the salinity, and showed a tendency to prefer the salinized habitats. Most loci were neutral to salinity. The morphological and genetic characters of BZH were special, and the speciality should not be determined by salinity. The morphological characters were affected by genetic information and environment. The morphological characters should change gradually and continuously along environmental gradient under plasticity, but should changed continuously or not in genetic control. The relevancies among quantitive characters, ecological factors and genetic variation in natural populations still will still be a focus and difficulty of ecological genetics of P. australis in the future.

• Korean Journal of Remote Sensing
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• v.26 no.6
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• pp.665-673
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• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.110-110
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• 1998

• Journal of Environmental Science International
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• v.11 no.4
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• pp.309-317
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• 2002

In this study, water protection reservoir is selected as the target which is located at the estuary of Taehwa river to analyze and examine the effects of hydraulic structure on river environment. This study examined the water quality variation characteristics among many effects of hydraulic structure on river environment before and after removal of the sediment protection reservoir when low flow is yielded. This study aims at the definition of factors which cause the change of ecological environment of river due to the effects of the sediment protection reservoir, and the proposal of the direction of environmental friendly river space development through the comparison of stream variation conditions(depth, velocity, and etc.) and riverbed variation characteristics with ecological depth condition of Taehwa-river's channel for each representative species of fish and examination those. Firstly, from the examination result of water quality when low flow is yielded before and after removal of the sediment protection reservoir for problems about water quality of river due to flow amount decrease in river, it is found that DO decreases about 0.78~0.86ppm at the lower stream of Myeongchon-gyo, and BOD decreases about 0.06~0.24ppm from right upper stream to the direction of estuary when the sediment protection reservoir is removed. It is known from the above that there is some improvement of water quality from the lower stream of Taehwa-gyo to the estuary in case of removal the sediment protection reservoir. Nextly, it is thought that the effects on ecosystem due to water depth and draw down in channel is not serious on the basis of the examination of water quality analysis result according to removal of sediment protection reservoir and hydraulic depths for reservation of ecosystem, these are 10~40cm for breeding season, 10~50cm for fry period, and 10~100cm for adult period of the representative species of fish in Korea.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.9-16
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• 2010

The purpose of this study is to clarify the origin of organic matters on sediment and the characteristics of seasonal variation at an estuarine tidal flat. Silt-clay content (<63 ${\mu}m$), chlorophyll a, TOC, C/N ratio and the stable isotope ratio of carbon and nitrogen were measured at tidal flat around the estuary of the Nanakita River. As a result, organic matters originating from marine organic matter and bethic microalgae greatly contributed to sedimentation of organic matters at Stn.A, sandy tidal flat, though terrigenous organic matters did at Stn.C, muddy tidal flat. Furthermore, it was revealed that the volume and origin of organic matters in the sediments depended on seasonal variation, and the factors were different from the Stns, i.e. bentic microalgae and event for Stn.A, and the eventual sedimentation of organic matters originating from terrestrial plants, respectively.

• Environmental Engineering Research
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• v.17 no.2
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• pp.77-82
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• 2012

The spatial variation of organic matter sources in tidal flat sediment of the Nanakita River estuary, involving Gamo lagoon on the north-east coast of Honshu Island, Japan, was examined using carbon stable isotopes and fatty acid biomarkers. The spatial variation of total organic carbon (TOC) contents and ${\delta}^{13}C$ values were highly variable in between the stations, such as sandy flat (1.3 mg/g, -21.0‰), sand-muddy flat (2.6 mg/g, -21.9‰), and muddy flat (24.9 mg/g, -25.9‰), respectively. Particularly, at the muddy flat, high TOC content and low ${\delta}^{13}C$ value of the sediments indicated that the surface sediment was composed largely of terrestrial organic matter. Whereas, at the sandy flat and sand-muddy flat, the high ratios of diatom and bacteria biomarkers indicated the high contribution of abundant microorganism along with marine organic matter in sediment composition. From these results, it considered that the amount and origin of transported sedimentary organic matter indicated different characteristics in this study stations.

• Korean Journal of Child Studies
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• v.21 no.4
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• pp.35-50
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• 2000

The objective of this research was to determine the relative impact of demographic variables and ecological factors on the parenting stress of dual earner families. Subjects were 318 fathers and 405 mothers who completed the questionnaire on parenting stress and ecological factors. Results showed that mothers perceived high parenting stress compared with fathers. Degree of satisfaction with child care was a significant correlate of parenting stress. Demographic and ecological factors were also important in understanding the variation in parenting stress of dual earner families. These findings imply that the formal child care systems and parent education programs are needed for working parents.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.39.1-39.1
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• 2008

• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.11-80
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• 1972