• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.27-33
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• 2015

Forest ecosystem is considered as an important stepping stone to minimize the impact of climate change. However, the rapid urbanization has caused fragmentation of forest ecosystem. The fragmentation of forest patch results in edge effect which brings about adverse impacts on forest function and structure. Degradation of forest ecosystem decreases carbon sequestration because edge effect reduces productivity. Therefore, we analyzed the impact of forest edge effect on forest ecosystem carbon stock change in Seongnam-si, Gyeonggi-do. We used connectivity analysis to determine forest edge and core area. The field study sites were selected with considering forest age, density, class and soil type. Secondly, forest carbon stock was calculated with allometric equation. The soil carbon stock was derived from Walkely-Black method. Lastly, Mann-Whitney test was conducted to validate differences between carbon stock in edge and core area. As a result of study, the connectivity analysis was effective to determine forest edge and core. The core and edge of forest patch showed different composition of tree species and soil properties. Carbon stock per tree in the edge area was lower than that in the core area. However, the difference of soil organic carbon content between the edge and core were relatively small. This assessment can be applied for the conservation of forest patch as well as quantitative assessment on the forest carbon stock change caused by fragmentation.

• Journal of the Mineralogical Society of Korea
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• v.30 no.2
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• pp.59-70
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• 2017

$SiO_2$ is one of the most abundant constituents of the Earth's crust and mantle. Probing its electronic structures at high pressures is essential to understand their elastic and thermodynamic properties in the Earth's interior. The in situ high-pressure x-ray Raman scattering (XRS) experiment has been effective in providing detailed bonding transitions of the low-z materials under extreme compression. However, the relationship between the local atomic structures and XRS features at high pressure has not been fully established. The ab initio calculations have been used to overcome such experimental difficulties. Here we report the partial density of states (PDOS) of O atoms and the O K-edge XRS spectra of ${\alpha}-quartz$, ${\alpha}-cristobalite$, and $CaCl_2$-type $SiO_2$ phases calculated using ab initio calculations based on the full-potential linearized augmented plane wave (FP-LAPW) method. The unoccupied O PDOSs of the $CaCl_2$-type $SiO_2$ calculated with and without applying the core-hole effects present significantly distinctive features. The unoccupied O p states of the ${\alpha}-quartz$, ${\alpha}-cristobalite$ and $CaCl_2$-type $SiO_2$ calculated with considering the core-hole effect present similar features to their calculated O K-edge XRS spectra. This confirms that characteristic features in the O K-edge XRS stem from the electronic transition from 1s to unoccupied 2p states. The current results indicate that the core-hole effects should be taken in to consideration to calculate the precise O K-edge XRS features of the $SiO_2$ polymorphs at high pressure. Furthermore, we also calculated O K-edge XRS spectrum for $CaCl_2$-type $SiO_2$ at ~63 GPa. As the experimental spectra for these high pressure phases are not currently available, the current results for the $CaCl_2$-type $SiO_2$ provide useful prospect to predict in situ high-pressure XRS spectra.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.78-82
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• 2001

Impact behaviors of Aluminum Honeycombs Sandwich Panel(AHSP) by drop weight test were investigated. Two types of specimens with 1/2" and 1/4" cell size were tested by two impactors which are weight of $5.25\textrm{kg}_{\textrm{f}}$ and $11.9\textrm{kg}_{\textrm{f}}$. Parametric studies were achieved including the impactor weight and impact sites which consist face, long-edge, short-edge, and point of the specimen. Face one of impact sites was the strongest and short-edge one of impact sites was the weakest. The damaged area of AHSP was enlarged with the increase of impactor weight that is equal to impact energy. After 3 point bending test, fracture modes of AHSP were analyzed with AE counts. Lower facesheet was fractured in the long-edge direction and then separated between facesheet and core. In the short-edge direction after core wrinkled, lower facesheet tear occurred. Impact behavior by FE analysis were increased localized damage in fast velocity because the faster velocity of the impact was, the smaller the stress of core was. Consequently, impactor weight had an effect on widely damaged area, while the impact velocity was caused on the localized damaged area.aged area.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.3
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• pp.549-559
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• 2023

As mobile edge computing (MEC) is gaining attention as a core technology of 5G networks, edge AI technology of 5G network environment based on mobile user data is recently being used in various fields. However, as in traditional AI security, there is a possibility of adversarial interference of standard 5G network functions within the core network responsible for edge AI core functions. In addition, research on data poisoning attacks that can occur in the MEC environment of standalone mode defined in 5G standards by 3GPP is currently insufficient compared to existing LTE networks. In this study, we explore the threat model for the MEC environment using NWDAF, a network function that is responsible for the core function of edge AI in 5G, and propose a feature selection method to improve the performance of detecting data poisoning attacks for Leaf NWDAF as some proof of concept. Through the proposed methodology, we achieved a maximum detection rate of 94.9% for Slowloris attack-based data poisoning attacks in NWDAF.

• KCI Concrete Journal
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• v.12 no.1
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• pp.91-99
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• 2000

A new type of retrof=t anchor bolt that uses deformed reinforcing bars and a commercial adhesive was developed and then an experimental study was carried out to determine the behavior of the anchors in direct shear. The steel-to-concl몫ete interface was tested. Plain concrete slabs with about 20-MPa compressive strength were used for 23 direct shear tests performed Test variables were anchor diameters (D16, D22. and D29) and edge effect. Three different shear tests were completed: simple shear, edge shear where anchors were pulled against the concrete core, and edge shear where anchors were pushed against the concrete cover In the simple and the edge shear tests where the anchors were pulled against the core, the theoretical dowel strength determined by (equation omitted) was achieved but with relatively large displacements. The shear resistances increased with the increasing displacements. In the edge shear test where the anchors were pushrd against the cover, the peak shear strengths signif=cantly lower than the theoretical dowel strength were determined due to cracks developed in concrete when the edge distance was 80 mm. The peak strengths were about 50% of the dowel strength for Dl6 bar. and about 25% or less of the dowel strength for D22 and D29 bars. Test results revealed that the edge shear where the anchor was pushed against the cover controled.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.572-574
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• 1998

In this paper, we are proposed design of ATM networks to transfer for electric power system informations, proposed transport networks is partitioned management part and functional part, management part is partitioned edge network, core network, local network, authority network, functional part is partitioned core network, access network, edge area. It is based on laying and partitioning by ITU-T G.805, we also proposed ATM network requirements for Carrier Relay traffic acceptability in electric power system information.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.682-697
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• 2001

This investigation evaluated the fracture toughness($K_{IC}$) of eight currently available core materials, and relate the fracture toughness value to fractography analysis and surface characteristics using a atomic force microscope (AFM). Single-edge notched (SEN) test specimens (n=10) and compact tension (CT) test specimens (n=10) were prepared conforming to the ASTM Standard E-399 for a high copper amalgam, three composite core materials (Core-Max II, Core Paste, Bisfil Core), two reinforced composite core materials (Ti-Core, Ti-Core Natural), a resin-modified glass ionomer core material (Vitremer), and a conventional glass ionomer core material (Ketac-Molar). The specimens were tested with an Instron Universal Testing Machine. The maximum loads were measured to calculate the fracture toughness ($K_{IC}$). Thereafter, fracture surfaces of SEN specimens of each material were investigated for fractography analysis using scanning electron microscope. And, disc-shaped specimens with 1mm thickness were fabricated for each material and were investigated under AFM for surface morphology analysis. The results were as follows: 1. Bisfil Core showed the highest mean fracture toughness regardless of test methods. 2. For the tooth-colored materials, Ti-Core Natural exhibited the highest fracture toughness. 3. Ketac Molar showed a significantly low fracture toughness when compared with the amalgam and the composite resin core materials(p<0.05). 4. The fracture toughness values obtained with the single-edge notched test, except Ketac Molar, were higher than those obtained in the compact tension test. 5. SEM revealed that the fracture surface of high fracture toughness material was rougher than that of low fracture toughness material. 6. AFM revealed that the surface particles of the composite resins were smaller in size, with a lower surface roughness than the glass ionomer core materials.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1321-1323
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• 2007

A new reference point location method based on an edge map is proposed, where an orientation map is defined and used to find the edge map. Experimental results show that the proposed method can effectively detect the core point in poor quality and arch-type fingerprint images and produces better results in terms of the detection rate and accuracy than the sine map-based method.

• Journal of the Korean Vacuum Society
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• v.20 no.4
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• pp.252-257
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• 2011

The ring formation and electronic properties of furan adsorbed on graphene layers grown on 6H-SiC (0001) has been investigated using atomic force microscopy (AFM), near edge X-ray absorption fine structure (NEXAFS) spectra for the C K-edge, and core level photoemission spectroscopy (CLPES). Moreover, we observed that furan molecules adsorbed on graphene could be used for chemical functionalization via the lone pair electrons of the oxygen group, allowing chemical doping. We also found that furan spontaneously form rings with one of three different bonding configurations and the electronic properties of the ring formed by furan on graphene can be described using by AFM, NEXAFS and CLPES, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.3
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• pp.29-44
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• 2016

The purpose of this study is to quantitatively and visually analyze the degree of green biotope fragmentation caused by road construction and other development work using FRAGSTATS and GUIDOS tool. Moreover, linking of the endangered species research, we mapped "Biotope Fragmentation Map" of Daejeon-city. The findings of the study are summarized as follows: First, as the result of FRAGSTATS, landscape indices : number of patch(NP), mean patch size (MPS), edge length(TE), mean nearest neighbor distance(MNN), edge shape(LSI) showed meaningful change from fragmentation. Moreover, the result of GUIDOS analysis, middle core-small core-bridge-branch-edge-islet-perforation showed increase of area percentage without large core. Lastly, analysis result of 'Biotope Fragmentation Map' revealed that changing site of large core's size appeared eighteen-site and designated as the special protection area appeared forty-one site. As the result of the two data, overlapping areas that showed both change of core size and revealed special protection areas revealed four site. For example, five species of endangered species appeared on the NO. 4 site in 'Biotope Fragmentation Map'. The findings of this study as summarized above are considered to play an important role in basic data preventing green biotope fragmentation at the planned level from various development work.