• Korean Journal of Environment and Ecology
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• v.9 no.2
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• pp.147-155
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• 1996

To investigate the structure and the conservation strategy of natural forest at Dongdaesan, Turobong, Sangwangbong Area in Odaesan National Park, 27 plots(20$\times$20m) set up with random sampling method. Three groups were classified by cluster analyses. High positive correlations was proved between Tilia amurensis and Acer pseudo-sieboldianum, Malus faccata and Syringa reticulata var. mandshurica, Prunus padus and Viburnum sargentii, and High negative correlations was proved between Quercus mongolica and pronus padus, Tilia amurensis and Prunus padus, Acer pseudo-sieboldianum and Prunus padus. Species diversity(H') of investigated area was calculated 0.9586~1.1814.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2011.04a
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• pp.285-289
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• 2011

he purpose of this study is to assess the effects of real estate policy on apartment price index in Seoul. To meet the research goal, this research reviewed real estate policy of the government from January of 1986 to August of 2010, and then it collected monthly apartment price index in 25 local districts of Seoul from January of 2003 to August of 2010. After 25 districts were grouped into 2 areas (14 districts in Gangnam and 11 districts in Gangbuk), the data of two areas were analyzed by using the SAS program, Cluster analysis with Ward method showed 3 clusters on each area, and with 6 clusters in total, the effects of real estate policy in the period were examined by using residual analysis. The analysis indicated two major shocks (one was from May to October of 2003, and the other was from March of 2006 to January of 2007), and the results showed that the intervention of government in the market had the asymmetric effects in bullish and bearish times. It implies that the market volatility is substantially influenced by irrational sentiments. Thus, it's suggested to devise the consumer sentiment index suitable in real estate market.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.579-588
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• 2009

The purpose of this study was to explain relationship between community structure and their environment variables in Mt. Hwaak. Samples were collected by 101 plots using ZM phytosociological method and followed by cluster, importance value and canonical correspondence analysis. The forest vegetation classified into 8 community types such as Pinus densiflora community, Berberis amurensis community, Betula ermani community, Betula schmidtii community, Larix leptolepis community, Pinus koraiensis community, Cornus controversa community and Salix koreensis community. Altitude was considered as the highest factor correlated to the community types. Berberis amurensis community and Betula ermani community were located in upper slope area of high elevation, Comus controversa community and Salix koreensis community in valley area, and Pinus densiflora community in ridge area, respectively.

• Convergence Security Journal
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• v.16 no.2
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• pp.3-9
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• 2016

Recently, a lot of researches have been done to increase the life span of network using the energy efficient sensor node in WSN. In the WSN environment, we must use limited amount of energy and hardware. Therefore, it is necessary to design energy efficient communication protocol and use limited resources. Cluster based routing method such as LEACH and HEED get the energy efficient routing using data communication between cluster head and related member nodes. In this paper, we propose an energy efficient routing algorithm as well as performance result using simulation.

• Advanced Composite Materials
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• v.18 no.1
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• pp.77-93
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• 2009

This paper investigated the damage transition mechanism between the fiber-breaking mode and the fiber-avoiding crack mode when the fiber-length is reduced in the unidirectional discontinuous carbon fiber-reinforced-plastics (CFRP) composites. The critical fiber-length for the transition is a key parameter for the manufacturing of flexible and high-strength CFRP composites with thermoset resin, because below this limit, we cannot take full advantage of the superior strength properties of fibers. For this discussion, we presented a numerical model for the microscopic damage and fracture of unidirectional discontinuous fiber-reinforced plastics. The model addressed the microscopic damage generated in these composites; the matrix crack with continuum damage mechanics model and the fiber breakage with the Weibull model for fiber strengths. With this numerical model, the damage transition behavior was discussed when the fiber length was varied. The comparison revealed that the length of discontinuous fibers in composites influences the formation and growth of the cluster of fiber-end damage, which causes the damage mode transition. Since the composite strength is significantly reduced below the critical fiber-length for the transition to fiber-avoiding crack mode, we should understand the damage mode transition appropriately with the analysis on the cluster growth of fiber-end damage.

• Development and Reproduction
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• v.15 no.4
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• pp.359-364
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• 2011

The seven selected primers OPA-02, OPA-04, OPA-18, OPD-07, OPD-08, OPD-15 and OPD-16 were used to generate unique shared loci to each species and shared loci by the two species. The hierarchical dendrogram indicates three main branches: cluster 1 (RORETZI 01~RORETZI 11) and cluster 2 (HILGENDORF 12~HILGENDORF 22) from two geographic populations of ascidians, Halocynthia roretzi and H. hilgendorfi. The shortest genetic distance displaying significant molecular difference was between individuals' HILGENDORF no. 14~HILGENDORF no. 19 (genetic distance =0.008). Ultimately, individual no. 02 of the RORETZI ascidian was most distantly related to HILGENDORF no. 21 (genetic distance=0.781). These results demonstrate that the H. roretzi population is genetically different from the H. hilgendorfi population. From what has been said above, the potential of PCR analysis to identify diagnostic markers for the identification of two ascidian populations has been demonstrated. Generally speaking, using a variety of decamer primers, this PCR method has been applied to identify specific markers particular to line, species and geographical population, as well as genetic diversity/polymorphism in diverse species of organisms.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.80-89
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• 2016

In the complex terrain where local wind systems are formed, accurate understanding of regional wind variability is required for wind resource assessment. In this paper, cluster analysis based on the similarity of time-series wind vector was applied to classify wind regions with similar wind characteristics and the meteorological validity of regionalization method was evaluated. Wind regions in Jeju Island and Busan were classified using the wind resource map of Korea created by a mesoscale numerical weather prediction modeling. The evaluation was performed by comparing wind speed, wind direction, and wind variability of each wind region. Wind characteristics, such as mean wind speed and prevailing wind direction, in the same wind region were similar and wind characteristics in different wind regions were meteor-statistically distinct. It was able to identify a singular wind region at the top area of Mt. Halla using the inconsistency of wind direction variability. Furthermore, it was found that the regionalization results correspond with the topographic features of Jeju Island and Busan, showing the validity.

• Journal of Intelligence and Information Systems
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• v.9 no.1
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• pp.179-193
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• 2003

Clustering is a data mining method which help discovering interesting data groups in large databases. In traditional data clustering, similarity between objects in the cluster is measured by pairwise similarity of objects. But we devise an advanced measurement called item similarity in this paper, in terms of nature of clustering transaction data and use this measurement to perform clustering. This new algorithm show the similarity by accepting the concept of relationship between different attributes. With this item similarity measurement, we develop an efficient clustering algorithm for target marketing in each group.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.1
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• pp.51-63
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• 1997

Total suspended particulate matters in the ambient air were analyzed for eight chemical elements (Ca, Co, Cu, Fe, Mn, Pb, Si, and Zn) using an x-ray fluorescence spectrometry (XRF) at the Kyung Hee University - Suwon Campus during 1989 to 1994. To use these data as basis for source identification study, membership of each sample was selected to represent one of the well defined sample groups. The data sets consisting of 83 objects and 8 variables were initially separated into two groups, fine (d$_{p}$<3.3 ${\mu}{\textrm}{m}$) and coarse particle groups (d$_{p}$>3.3 ${\mu}{\textrm}{m}$). A hierarchical clustering method was examined to obtain possible member of homogeneous sample classes for each of the two groups by transforming raw data and by applying various distances. A disjoint principal component analysis was then used to define homogeneous sample classes after deleting outliers. Each of five homogeneous sample classes was determined for the fine and the coarse particle group, respectively. The data were properly classified via an application of logarithmic transformation and Euclidean distance concept. After determining homogeneous classes, correlation coefficients among eight chemical variables within all the homogeneous classes for calculated and meteorological variables (temperature. relative humidity, wind speed, wind direction, and precipitation) were examined as well to intensively interpret environmental factors influencing the characteristics of each class for each group. According to our analysis, we found that each class had its own distinct seasonal pattern that was affected most sensitively by wind direction.ion.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.227-230
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• 1999

The sphenopalatine ganglion lies behind the middle nasal concha in the sphenopalatine foramen which connects the fossa to the nasal cavity. It has sympathetic and parasympathetic fibers as well as sensory fibers which innervate the nasal cavity, palate and nasopharynx. Current indications for blockade of the sphenopalatine ganglion include the management of migraine, cluster headache and a variety of facial neuralgias. Blockage of this ganglion can be attempted when more conservative treatments have failed. If the pain relief gained through the procedure is of short duration and the blockage needs to be repeated frequently, then radiofrequency thermocoagulation should be considered. Since the sphenopalatine ganglion lies close to the maxillary nerve, neurolytics can cause facial dysesthesia, radiofrequency thermocoagulation is the preferred method for ganglionotomy. Radiofrequency thermocoagulation of the sphenopalatine ganglion was done for 3 patients who suffered from postherpetic neuralgia, cluster headache, atypical facial pain respectively. Good results were obtained with the exception of the patient suffering from atypical facial pain. Although we were concerned about complications such as epistaxis, none were encountered. However it should be noted that caution must be exercised when repeatedly redirecting the cannula in the sphenopalatine fossa as serious bleeding and pronounced facial swelling may result.