• Korean Journal of Environment and Ecology
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• v.3 no.1
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• pp.28-41
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• 1989

A survey of Hongryu-Dong and Chi-in district. Gaya National Park, was conducted using 40 sample sites of 500$m^2$ size. TWINSPAN classification confirmed a complex pattern of both local and geographical variation in the vegetation: Dry and wet community types. Within dry community types, two floristic assocation of Pinus densiflora were defined according to local variation. Within wet community types. two floristic association were defined according to altitude. Those associations can be further subdivided floristically into eight subassociation. The vegetation pattern presented by DCA ordination corresponds to one of TWINSPAN at the first two division. The DCA ordination was successful in separating Pinus densiflora from broad leaf forest. Ordination of samples produced arrangements reflectly environmental gradient of soil. The correlation between the first axe of DCA and soil moisture, soil acid, altitude, maximum species diversity and species diversity was significantly negative. The similarity index between each community was very low level.

• Korean Journal of Environment and Ecology
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• v.10 no.2
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• pp.283-296
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• 1997

To investigate the plant community structure in valley and suggest the management of Mational Park, fifty plots were set up and surveyed in Jujeongol Valley, Soraksan National Park. The classification by TWINSPAN and DCA ordination technique were applied to the study area in order to classify them into several groups based on woody plants. The dividing groups were Quercus mpnngolica - Q. variabilis - Pinus densiflora community, P. densiflora community, Carpinus laxiflora community, Q. serrata community. The ecological trends of tree species by DCA ordination technique and DBH class distribution analysis was like that Q. mongolica - Q. variabilis - P. densiflora community and P. densiflora community seems to be trended from P. densiflora community to Q. mongolica community. Q. serrata community seems to be trended from Q. serrata community to C. laxiflora community and C. laxiflora will be maintaimed stable state.

• Journal of Korean Society of Forest Science
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• v.77 no.1
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• pp.73-82
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• 1988

This study was excuted to analyze the vegetational community structure of the Hongrudong valley the Mt. Gaya by three kinds of ordination techniques (polar, principal component analysis, reciprocal averaging). Eleven sites were sampled with the clumped method to analyze the vegetation structure. The result suggested that Hongrudong valley forest was divided by Pinus densiflora and Quercus aliena community. The relation between stand scores of ordination and soil pH, humus content, soil moisture had a tendency to increase significantly from P. densiflora to Q. aliena community. RA was the most effective method of this study. RA ordination was showed that successional trends of tree species seem to be from P. densijlora through Q. variabilis to Q. aliena, Carpinus laxiflora in the upper layer and from Lespedeza cyrtobotrva, Rhus spp., Rhododendron schlippenbachii through Fraxinus sieboldiana, Lindera obtusiloba to Euonymus oxyphyllus, Weigela subsessilis, Callicarpa japonica in the middle layer.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.129-140
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• 1982

Herbicides were classified by two-dimensional ordination analysis based on the weed flora which was not controlled by application of a particular herbicide. The number of herbicide group was varied depending upon the weed community type and the experiment site. The technique of the two-dimensional ordination analysis gave more comprehensive informations about selecting of herbicides for increasing the herbicidal efficacy, for increasing the weed spectrum and for reducing the herbicide cost by mixing of herbicides. The two-dimensional ordination analysis could be used not only herbicide classification and selecting effective herbicide or herbicide combination but also can be used for the evaluation of systematic application of herbicides.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.285-294
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• 2015

Ordination has been recognized useful method to analyze the effects of multiple environmental factors on dozens of species in vegetation ecology because of summarizing community data by producing a low-dimensional graphics. Main objective of this study was the application of ordination method, especially principal components analysis (PCA), to analyze the soil characterization on paddy treated by different green manure crops and tillage methods. Treatments included the three tillage treatments and two green manure crops as the following; (i) moldrotary + rotary tillage without green manure crop (Con), with (ii) hairy vetch (ConHv), and (iii) hairy vetch + green barely (ConHvGb), (iv) rotary tillage without green manure crop (Rot), with (v) hairy vetch (RotHv), and (vi) hairy vetch + green barly (RotHvGb), and (vii) no-tillage (Notill). Vectorial distance result from PCA of soil properties including physical, chemical, and microbial properties showed the two main difference. Firstly, soil properties among plots without green manure were strongly affected by tillage strength [Vectorial distance: Con-Notil (5.88) > Rot-Notill (4.58)] at PC1 (35.0%) axis. But it was difficult to find the fixed trend among plots when green manure crop was added in plot. Nevertheless, two groups were separated by adding green manure crop at PC2 (29.2%) axis. These results show that PCA ordination methods could be used the research for change of soil characterization.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.63-87
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• 1995

The present study was undertaken to classify and describe the Quercus mongolica forest on Mt. Sobaek (36°50'∼ 37°07'N, 128°25'∼ 128°35'E), Korea by a reciprocal averaging methol (RA ordination) and the methodology of the ZM school of phytosociology. Atemporal vegetation tabel was prepared by the RA ordination. As a result it showed that the RA ordination on the first axis is very applicable for selecting the character and differential species of vegetation units of the Quercus mongolica forest. The phytosociological investigations were carried out in 34 stands on the mountain. The field data obtained were classified by the tabel comparison method. For the establishment of new vegetation units, the floristic composition of the Quercus mongolica forest was compared with those of the other vegetation units of the Mt. Sobaek, Considering the candidates of the character and differential species derived from RA ordination. As the result, the forest vegetation was classified into the following vegetation units; Fagetea crenatae Miyawaki et al. 1968 Acero-Quercetalia mongolicas Song 1988 em. Takeda et al.1994 Lindero-Quercetalia mongolicae Kim 1990 1. Lindero-Quercetum mongolicae assoc. nov. 1-1. quercetosum serratae subassoc. nov 1-2. typicum subassoc. nov. Rhododendro-Qurcion mongolicas Song 1988 em. Takeda et al. 1994. It is inferred that the Lindero-Quercion mongolicae and the Rhododendro-Quercion mongolicae corresponded to the cool-temperate forests of central and northern areas, respectively, in Korean Peninsula. Syntaxonomical synonyms were also rearranged based on the result of the present study. On the other hand, the RA ordination of stands and species on the first and second axes revealed some environmental gradients such as altitute, human impact and species richness between the vegetation units. However, the RA ordinations is considered to be less indicative for the gradients of the lower vegetation units than association. With the present study. some phytosociological problems in Korea were discussed here in detail from the floristic viewpoint.

• Korean Journal of Environment and Ecology
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• v.11 no.3
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• pp.290-309
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• 1997

To investigate the plant community structure in Gunpo Experimental Forest of Mt. Suri, Kyonggi-do, sixty-four plots were set up and surveyed. By DCA ordination technique, sixty-four plots were divided into seven groups. The dividing groups were * Pinus rigitaeda community, P. densiflora community, P. densiflora-Quercus mongolica community, Q. variabilis community, Q. aliena comunity, Q. serrata community, Carpinus laxiflora community. Though the successional trend of seven communities by DCA ordination technique and DBH class distribution analysis was not clearly inferred, * Pinus rigitaeda community and P. densiflora-Q: mongolica community seems to be trended from present state to Q. spp. community. P. densiflora community, Q. variabilis community, Q. aliena community and Q. serrata community seems to be maintained preaent state and C. laxiflora community will be maintainde stable state. Shannon's diversity was 0.7430~1.3025(unit area: 300m$^{2}$) and soil acidity was pH 4.16~5.13 in surveyed areas.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.166-177
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• 1988

To investigate the structure of the plant community of the Naejang Temple District in Mt. Naejang National Park, 22 plots were set up by the vegetation physiognomy and vegetation analysis by four kinds of ordination techniques(PO, PCA, RA and DCA) was carried out. Pure and mixed forest community of Quercus variabilis and Q. mongolica were major forest communities and each of them covered 31.27 and 20.77%, respectively. The degree of human disturbance of vegetation 9, 8, 7 and 6 area covered 30.9, 67.0, 0 and 0.02%, respectively. According to stand dynamic analysis by DBH class distribution, the present Pinus densiflora and Quercus communities may be succeeded to Carpinus laxiflora communities. DCA was the most effective method of this study. DCA ordination showed that successional trends of tree species seem to be from P. densiflora through Q. variabilis, Q. aliena, Sorbus alnifolia, Platycarya strobilacea to Carpinus laxiflora, Fraxinus rhynchophylla, Zelkova serrata, Cornus controversa in the tree layer, and from Rhododendron mucronulatum, Rh. schlippenbachii, Lespedeza cyrtobotrya, Rhus trichocarpa through Styrax japonica, Daphniphyllum macropodum, Sapium japonicum to Euonymus oxyphyllum, E. sieboldiana, Lindera erythrocarpa in the subtree layer.

• The Korean Journal of Ecology
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• v.8 no.3
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• pp.147-152
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• 1985

The forest vegetation of natural reserve area (175ha) at north-eastern slope of Solibong (537m), Gwangneung, was studied by plant sociological method and two dimensional ordination technique. In the area dominated by Carpinus laxiflora, from the lower site to peak of Solibong, a zonal distribution of C. laxiflora-Quercus mongolic forest, C. laxiflora-C. cordata forest, C. laxiflora-Q. serrata forest, C. laxiflora forest and C. laxiflora-Rhododendron schlippenbachii forest were recognized by the plant sociological survey. It is seem that the optimal range of Carpinus laxiflora forest occur in mesic-warm site by two dimensiional ordination with thermal condition and soil moisture condition. The optimal range (over 100 in importance value) was the range of 76~89。C.month in warmth index and 18~45% in soil water content.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.159-162
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• 2002

A software, called touch-one, is developed about the determination of short-circuit values and protective co-ordination in power system. The used solution algorithm reviewed intensively, and the protective co-ordination determination technique presented by using the circuit-breaker's current-limitation characteristic. The protective coordination concerns the behaviour of two devices placed in series in an electrical network, with a short-circuit downstream circuit-breaker. It has two basic principles: First, discrimination which is an increasing requirement of low voltage electrical distribution systems. Second, which is less well known: cascading, which consists of installing a device, whose breaking capacity is less than the three-phase short-circuit current at its terminals and helped by main circuit-breaker. With this software, we can construct a electric-power system which is reliable and economic according to user's purpose.