• The Journal of Engineering Geology
• /
• v.26 no.1
• /
• pp.117-128
• /
• 2016

Chemical reaction tests were performed to assess the properties of hardened specimens of cement pastes (KS-1 Portland and Class G) exposed to supercritical CO₂ for 1, 10, and 100 days. After exposure, the samples' measured permeability and strength were compared with values measured for pristine samples. The pristine cements had permeabilities of 0.009~0.025 mD, which increased by one order of magnitude after 100 days of exposure (to 0.11~0.29 mD). The enhancement of permeability is attributed to the stress release experienced by the samples after removal from the pressure vessel after exposure. Despite its enhancement, the measured permeability mostly remained lower than the API (American Petroleum Institute) recommended maximum value of 0.2 mD. The degradation of the cement samples due to exposure to supercritical CO₂ led to a layer of altered material advancing inwards from the sample edges. The Vickers hardness in the altered zone was much higher than that in the unaltered zone, possibly owing to the increase in density and the decrease in porosity due to the carbonation that occurred in the altered zone. Hardness close to the edge within the altered zone was found to have decreased significantly, which is attributed to the conversion of C-S-H into less-strong amorphous silica.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.42 no.1
• /
• pp.123-132
• /
• 2014

This study aims to develop the diagnostic evaluation method of the riverine ecobelt for construction, conservation, and maintenance of the riverine ecobelt. The value indices in the proposed evaluation method are composed of total 5 fields and 19 elements. The 5 fields are flood control, environmental function, growth of plants, ecobelt function, and restoration potential. Flood control field is composed of total 3 elements such as length, width, and density of green area. Environmental function field is composed of 4 elements such as park use, landscape boundary and edge, microclimate control, non-point pollution control. Growth of plants field is composed of 6 elements such as species composition, forest height, stratum structure, vine plants, plant vitality, and succession of plants. Ecobelt function field is composed of 4 elements such as longitudinal connectivity, lateral connectivity, in-stream forest or habitat, roads on bank top. Restoration potential field is composed of 2 elements such as landform and land use of the immediate vicinity. The score system ranging 1~4 was adopted. The weighting parameters of elements were unified with each other. The final grade system ranging 1~5(1: very good~5: very bad) was adopted, and the final grade was evaluated by the mean values of each field. According to the test application of the diagnostic evaluation method of the riverine ecobelt, the final grades showed effectively the real condition of each site.

• Journal of Environmental Impact Assessment
• /
• v.25 no.6
• /
• pp.432-441
• /
• 2016

In this study, we predicted species distributions in Mt. Inwang and Mt. An as preceding research to build ecological corridor by considering connectivity of habitats which have been fragmented in the city. We analyzed species distributions by using Maxent (Maximum Entropy Approach) model with species presence. We used 23 points of mammals and 15 points of Titmouse (Parus major, P. palustris, P. varius) as target species from appearance points of species examined. We build 4 geography factors, 4 vegetation factors, and 2 distance factors as model variables In case of mammals, factors that affected species distribution model was Digital Elevation Model(DEM, 34%) followed by Distance from edge forest to interior (24.8%) and Species of tree (10%). On the other hand, in case of Parus species, factors that affected species distribution model were DEM (39.6%) followed by distance from road (35.4%) and Density-class (8.2%). Therefore, birds and mammals prefer interior of mountain, and this area needs to be protected.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.4
• /
• pp.1-8
• /
• 2014

As cores in multi-core processors are integrated in a single chip, power density increased considerably, resulting in high temperature. For this reason, many research groups have focused on the techniques to solve thermal problems. In general, the approaches using mechanical cooling system or DTM(Dynamic Thermal Management) have been used to reduce the temperature in the microprocessors. However, existing approaches cannot solve thermal problems due to high cost and performance degradation. However, floorplan scheme does not require extra cooling cost and performance degradation. In this paper, we propose the diverse floorplan schemes in order to alleviate the thermal problem caused by the hottest unit in multi-core processors. Simulation results show that the peak temperature can be reduced efficiently when the hottest unit is located near to L2 cache. Compared to baseline floorplan, the peak temperature of core-central and core-edge are decreased by $8.04^{\circ}C$, $8.05^{\circ}C$ on average, respectively.

• Journal of Korean Society of Forest Science
• /
• v.76 no.3
• /
• pp.206-217
• /
• 1987

To investigate and analyze the vegetational structure, thirty sites were sampled with clumped sampling method and seventeen belt transects were sampled to analyze the vegetational change during 8 years(from 1978 to 1986)at the Namsan Nature Park in Seoul. Robinia pseudoacacia community of actual vegetation covered 29.39%, Quercus mongolica community 21.25% and Pinus densiflora community 17.58% of the Mt. Namsan forest. The degree of human disturbance of vegetation of 8, 7 and 6 area covered 43.2%, 7.8% and 30.8% respectively. The Quercus mongolica community at the northern slope and R. pseudoacacia community at the edge zone will keep their present structure. And P. densiflora community at the eastern and southern slope shall be succeeded to deciduous trees such as Q. mongolica. As to changes of plant community structure during 8 years, density of understory species, species diversity and Raunkiaer's frequency class A and E showed an increase and vegetation structure was developed to unification.

• Korean Journal of Environment and Ecology
• /
• v.1 no.1
• /
• pp.24-34
• /
• 1987

This study was conducted to investigate avifauna and user's effect on the avifauna in Bukhan Mountain district of Bukhan Mountain National Park. Avifauna were investigated bimonthly from April to October 1987 over four districts which were main trail and sub-trail in each valley and ridge-midslope region by line transect methods. The observed birds in Bukhan Mountain districts was 34 species and 753 individuals and these consist of 19 species for residents. 11 species for summer visitor. 2 species for passage migrant and 2 species for winter visitor. The dominant species were Parus major (22.7%), Paradoxornis webbina(10%), Parus palustris (10.8%), Pica pica (10.0%) in order. No. of species and species diversities was higher in valley region than in ridge-midslope region. No. of species, individuals and species diversities were lower in main trail of high user's density than in sub-trail. Especially avifauna in main trail was severely decreased in August in valley region in which users were concentrated. But there was no change in similarity indices according to user's intensities. Therefore avifauna protection policy such as restoration and rehabilitation of edge species along trail, user's control in valley region during breeding periods, etc., shall be made for Bukhan Mountain National Park.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.1
• /
• pp.17-25
• /
• 2007

In most electronic imaging applications, image with high resolution(HR) are desired. HR means that pixel density within an image is high, and therefore HR image can offer more details that may be critical in various applications. Digital images that are captured by CCD and CMOS cameras usually have a very low resolution, which significantly limits the performance of image recognition systems. Image super-resolution techniques can be applied to overcome the limits of these imaging systems. Super-resolution techniques have been proposed to increase the resolution by combining information from multiple images. To techniques were consisted of the registration algorithm for estimation and shift, the nearest neighbor interpolation using weight of acquired frames and presented frames. In this paper, it is proposed the image interpolation techniques using the wavelet base function. This is applied to embody a correct edge image and natural image when expend part of the still image by applying the wavelet base function coefficient to the conventional Super-Resolution interpolation method. And the proposal algorithm in this paper is confirmed to improve the image applying the nearest neighbor interpolation algorithm, bilinear interpolation algorithm.,bicubic interpolation algorithm through the computer simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.2
• /
• pp.161-172
• /
• 1997

In this paper, electromagnetic scattering by a perfectly conducting strip grating on dielectric multilayers is analyzed for the normalized reflected and transmitted power by applying the Fourier-Galeakin moment method. The induced current density is expanded in a series of multiplication of chebyshev polynomials of the first kind and functions with appropriate edge boundary condition, the continuous condition of electromagnetic field is applied in the boundary planes. The confirm the validity of the proposed method, the nor- malized reflected and transmitted power obtained by varying the relative permittivity and thickness of each dielectric layers are evaluated and compared with those of the existing numerical method and a paper, and then the numerical results in this paper are in good agreement with those of the existing numerical method and the paper. The sharp variation position in the geometrically normalized reflected and transmitted power can be moved by the incident angle, grating period, and the relative permittivity and thickness of the dielectric multilayers, these sharp variation points which are called the Wood's anomaly of the Geome- trically normalized reflected power are observed as a main factor when the reflected powers of the higher order mode are transitted between propagating and evanescent modes, and the local minimum positions are slightly moved to the left hand direction in which grating period is getting small according to the increase of the relative permittivity of dielectric layers.

• Journal of Korean Society of Forest Science
• /
• v.87 no.3
• /
• pp.459-465
• /
• 1998

To obtain the basic data for the conservation and cultivation of native herb species under the forest, the relations between distribution of native herb species and site factors, distribution of native herb species, and site factors were surveyed on natural forest at subalpine zone in Mt. Odae. Ainsliaea acerifolia, Pseudostellaria palibiniana and Pimpinedla brachycarpa were distributed mainly on broadleaved mixed forest, Clematis fusca var. coreana, Carex siderosticta. Isodon excisus and Vicia unijuga did mainly on gab sites. The distribution of Ligularia fisheri, Aconitum pseudo-laeve var. erectum, Cacalia hastata and Artemisia stolonifera were significantly differed between slope directions. Artemisia stolonifera was distributed more frequently in south directed slope, and Ligularia fisheri, Aconitum pseudo-laeve var. erectum and Cacalia hastata were distributed more frequently in north and west directed slope than the other. The distribution of Aconitum pseudo-laeve var. erectum and Artemisia stolonifera were significantly differed between soil moisture conditions. Artemisia stolonifera was distributed mainly on the dry site, but Aconitum pseudo-laeve var. erectum did mainly on the dry site. Negative correlations between density of Clematis fusca var. coreana, Carex siderosticta. Isodon excises and Vicia unijuga and crown coverage was proved. Aconitum pseudo-laeve var. erectum, Pimpinella brachycarpa, Meehania urticifolia, Smilacina japonica and Pseudostellaria palibiniana were mainly distributed on wet and shady sites under forest canopy, but Pedicularis resupinata, Clematis fusca var. coreana and Artemisia stolonifera did on sunny sites at forest edge or gab.

• Progress in Medical Physics
• /
• v.12 no.1
• /
• pp.95-102
• /
• 2001

The intracavitary cones were designed which were made of stainless steel and have scratched inside cone to be generated electron scatter and designed to be attached easily to the LINAC collimator and controlled cones length to be contacted smoothly between the patient and the cone tip. Two types of intracavitary cones were designed. One is the straight end cones with circular opening on the distal end and the other is 30 degree beveled end cones with elliptical opening on the distal end. Each type of intracavitary cone ranged in daimeter from 2.5 cm to 3.5 cm and required a separate set of lower trimmer annulias cone diameter. The film phantom was designed with an internal cassette that accurately aligned the film edge with the film phantom surface. Film optical density data were measured by photodensitometer(Wellhofer 700i) Dosimetry measurements were made to commission the LINAC for 6 - 20 MeV electron using the intracavitary cones. Isodose curves were measured for all energy and cones combinations. Output is defined as the maximum dose per MU along the clinical central axis in water at 113 cm SSD. Calibration output, defined to be the output for the 15cm$\times$15cm diameter straight cone, was adjusted to 1.00 cGy/MU at each energy according to the TG-21 protocol.