• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.129-143
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• 2014

The purpose of this study is to evaluate flooding vulnerability considering spatial characteristics focused on Changwon-si, Gyeongsangnam-do. Assessment Factors are water cycle area ratio, surface runoff, and precipitation. And construction of assessment factors and vulnerability was analyzed by GIS program. Water cycle ratio and surface runoff were vulnerable in urban area. Precipitation was often distributed in agriculture of the northern region. Results of flooding vulnerability were low in agriculture and forest of the northern region. In contrast, urban area was high because there has covered impervious land cover. Analytical results of flooding vulnerability density using hotspot spatial cluster analysis were high in urban area. And these areas were situated in down stream so flooding were generated. Therefore, flooding vulnerability assessment of this study can help for selecting construction sites of pervious land cover and rainwater management facilities in urban and environmental planning.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.73-80
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• 2016

The Car License Plate Recognition(: CLPR) is required in searching the hit-and-run car, measuring the traffic density, investigating the traffic accidents as well as in pursuing vehicle crimes according to the increasing in number of vehicles. The captured images on the real environment of the CLPR is contaminated not only by snow and rain, illumination changes, but also by the geometrical distortion due to the pose changes between camera and car at the moment of image capturing. We propose homographic transformation and intensity histogram of vertical image projection so as to transform the distorted input to the original image and cluster the character and number, respectively. Especially, in this paper, the Multilayer Perceptron Algorithm(: MLP) in the CLPR is used to not only recognize the charcters and car license plate, but also determine the optimized ratio among the number of input, hidden and output layers by the real experimental result.

• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.159-166
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• 1999

The physical properties and microstructural changes with heat-treatment of opacified silica aerogels doped by TiO2 were investigated. Monolithic SiO2-TiO2 aerogels were prepared by supercritical drying (25$0^{\circ}C$, 1250 psig) of wet gel obtained by adding titanium isopropoxide to prehydrolyzed TEOS-isopropanol solutions. The density and the porosity of SiO2-10 mol% TiO2 aerogels were 0.23 g/㎤ and 90%, respectively. During supercritical drying, the linear shrinkage of aerogels increased with increase in the titanium content an TiO2 was transformed to the anatase phase as well as particls agglomerates led to TiO2 clusters of 100~800 nm dispersed homogeneoulsy in the silica matrix. The IR transmittance of opacified silica aerogels was very low in the region of wavelengths below 8 ${\mu}{\textrm}{m}$ compared with pure silica aerogels and SiO2-TiO2 aerogels showed the high thermal stability of microstructures up to $600^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.341-342
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• 2008

The dynamics of nano particles in LC medium under an external electric field is of theoretical and technological interest. In this work, the dynamical characteristics of fullerene $(C_{60})$ particles in liquid crystal (LC) medium under dc electric field have been investigated. This effect was studied for homogeneously aligned nematic LC cells driven by in-plane field. The $C_{60}$ was found to be aggregated in a form of cluster inside the LC medium. Hence polystytene was used to protect the aggregation of $C_{60}$ in LC medium. When the electric field was applied, the fullerenes start to move in direction of applied electric field. The density of $C_{60}$'s particles at the electrodes increase with increase in the value of applied electric field. The dynamical motions of fullerene $(C_{60})$ particles in liquid crystal (LC) suggest that fullerene can be designed for electrophoretic displays (i.e., electronic ink).

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.258-265
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• 1995

Regeneration process of edaphic pine(Pinus densiflora) climax forest in Bulyung-gyegog, Uljin-gun, Kyungsangbuk-do, was studied. The height of dominant trees in the stands are 12 15m. Upper layers are highly dominated by pine trees and are randomly distributed. Pine trees in lower layer grow in a patch type. In the upper layer, the age distribution is likely one model type with mode of 60 and 80 years. In the horizontal distribution of these trees, some of the even-aged cluster constituted of several tree were found. For the first 25 years, the stem diameter increment rates in upper layer are higher than those in the middle layer. It could be concluded that after the forest canopy had been broken out, the seedlings established densely in a patch in the gap with the decreasing density and some of them, distributed in random, would constitute the canopy.

• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.77-85
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• 2015

Recently, wireless sensor network(WSN) have been used in various fields to implement ubiquitous computing environment. WSN uses small, low cost and low power sensors in order to collect information from the sensor field. This paper proposes a clustering algorithm for energy efficiency of sensor nodes. The proposed algorithm is based on conventional LEACH, the representative clustering protocol for WSN and it prolongs network and nodes life time using sleep technique and changable transmission mode. The nodes of the proposed algorithm first calculate their clustering participation value based on the distance to the neighbor nodes. The nodes located in high density area will have clustering participation value and it can turn to sleep mode. Besides, proposed algorithm can change transmission method from conventional single-hop transmission to multi-hop transmission according to the energy level of cluster head. Simulation results show that the proposed clustering algorithm outperforms conventional LEACH, especially non-uniformly deployed network.

• Ocean and Polar Research
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• v.29 no.2
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• pp.123-134
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• 2007

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 km of the coastline using a Smith-McIntyre grab $(0.05\;m^2)$ in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of $1,972\;ind./m^2$, and mean biomass was 82.5 wet-weight $g/m^2$. The major individual-dominant species were three polychaetes Spiophanes bombyx ($436\;ind./m^2$), Scoletoma longifolia ($250\;ind./m^2$) and Magelona japonica ($170\;ind./m^2$), and bivalve Adontorhina subquadrata ($73\;ind./m^2$). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group I contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group I was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (I-I and I-II) in relation to depth. Sub-group I-I was associated with deeper sites than sub-group I-II. Group II included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group II was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.

• Ocean and Polar Research
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• v.36 no.3
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• pp.209-223
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• 2014

The community structure of benthic meiofauna was investigated from seasonal surveys at seventeen stations off the Saemangeum area, in 2007. Ten meiofaunal taxa were identified. Nematodes were the dominant faunal group in all seasons and harpacticoids were dominant only at a few stations. The mean density of meiofauna was 383 indiv. $10cm^{-2}$, highest in May and November (434 indiv. $10cm^{-2}$), lowest in February (284 indiv. $10cm^{-2}$). Meiofaunal mean biomass was $80.49{\mu}gC{\cdot}10cm^{-2}$, highest in November ($99.54{\mu}gC{\cdot}10cm^{-2}$), lowest in February ($51.56{\mu}gC{\cdot}10cm^{-2}$). Cluster analysis revealed that the study area was composed of three benthic meiofaunal communities. There were significant correlations between major meiofaunal groups and sediment composition and the concentrations of heavy metals. The abundance of harpacticoids are positively correlated with silt (0.559, p < 0.01) and clay (0.340, p < 0.01), and negatively correlated with sand (-0.548, p < 0.01). Harpacticoids also showed positive correlations with heavy metals. The community structure of meiofauna in the study area varied seasonally in response to the change of sediment composition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.189-197
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• 2006

To elucidate the organic matter sources in soft-bottom macrozoobenthos at Tongyeong, Korea, macrozoobenthos and their potential food sources were sampled in May 2004, and their C and N stable isotope compositions were analyzed. In total we collected 128 macrozoobenthic species, which ranged from 465 to 3,775 individuals/$m^2$(average 2,108 ind.$m^2$) in density and from 47.8 to 539.9 gwwt/$m^2$(average 366.0 gwwt/$m^2$) in biomass. Cluster and multi-dimensional scaling analyses indicated that the macrozoobenthic community was divided into two distinct groups. Coastal inner stations, where commercial fish cages were established, were dominated by Amphioplus ancistrotus, Scoletoma longifoila and Tharyx sp., whereas open sea stations were dominated by Chaetozone spinosa, Scoletoma longifolia and Capitella capitata. ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -18.4 to $-15.2\%_{\circ}$, with a declining trend from the coastal inner stations to open sea stations. This probably reflects the settling rate of organic wastes such as feces and pellets from fish cages near the coastal inner stations. The macrozoobenthos showed a broad ${\delta}^{13}C$ range from -19.5 to $-8.9\%_{\circ}$ at the coastal inner stations, and a relatively narrow range from -21.3 to $-12.9\%_{\circ}$ at the open sea stations. ${\delta}^{13}C$ values of macrozoobenthos paralleled those of sedimentary organic matter, Our isotope results suggested that macrozoobenthos near the coastal inner stations used organic wastes derived from fish cages along with phytoplankton, whereas the macrozoobenthos near the open sea stations used organic wasters derived mainly from phytoplankton.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.95-105
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• 2014

In this paper, we present a novel ant-based hierarchical clustering algorithm, where ants repeatedly hop from one node to another over a weighted directed graph of k-nearest neighborhood obtained from a given dataset. We introduce a notion of node pheromone, which is the summation of amount of pheromone on incoming arcs to a node. The node pheromone can be regarded as a relative density measure in a local region. After a finite number of ants' hopping, we remove nodes with a small amount of node pheromone from the directed graph, and obtain a group of strongly connected components as clusters. We iteratively do this removing process from a low value of threshold to a high value, yielding a hierarchy of clusters. We demonstrate the performance of the proposed algorithm with synthetic and real data sets, comparing with traditional clustering methods. Experimental results show the superiority of the proposed method to the traditional methods.