• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.11-17
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• 1999

Morphological variations in leaves and leaf trichomes according to tree age were investigated for the identification of Quercus taxa at the different stages of development. The sizes of leaves from one-year-old seedlings of Q. serrata, Q. dentata, and Q. aliena were the smallest and increased with tree age. Blade length, blade width, petiole length, number of serration, and serration depth war also varied with tree age. Therefore, the examined taxa by the size and form of leaves were hardly identified at juvenile stages. The type, structure, and density of leaf trichomes of each species varied remarkably along with tree age. Three types of trichomes such as small stellate hairs, large stellate hairs, and long single hairs were observed on the abaxial side of leaves of Quercus taxa. In matured trees of Q. serrata both small stellate and long single hairs on leaves were observed. On the other hand large stellate hairs were found in leaves of Q. dentata. There were small stellate hairs in Q. aliens. In Q. mongolica var. crispula, no hair or small stellate hairs were occasionally found. It is possible to identify Q. serrata and Q. dentata by the characteristics of trichome even at two to three year old seedlings, while, it is difficult to tell Q. aliens and Q. mongolica var. crispula of seedlings from other taxa only by those of trichome.

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.111-116
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• 1999

Distribution of heavy metal (Zn, Pb, Cu, Cd) concentrations within forest soils was investigated in Mts. Surak and Bulam around the outskirt area, and Mts. Bukak and Inwang around the downtown area of Seoul. Metal concentrations in these soils were higher in the A horizons than in the B horizons. The mean concentrations of Zn, Pb, Cu, and Cd in the A horizons were 4.39 mg/kg, 9.09 mg/kg, 1.67 mg/kg, and 0.03 mg/kg, respectively. The concentrations in the B horizons were 2.18 mg/kg in Zn, 5.74 mg/kg in Pb, 0.55 mg/kg in Cu, and 0.01 mg/kg in Cd, respectively. With positive correlation among the metal concentrations, Zn, Pb, and Cu concentrations in the A horizon were positively correlated with soil organic matter contents (r=0.39~0.83, p<0.01), while Pb and Cu concentrations were negatively correlated with soil pH (r=-0.53~0.59, p<0.01). The results suggest that the metals in forest soils have accumulated more in the downtown than in the outskirt areas.

• Journal of Korean Society of Forest Science
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• v.96 no.4
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• pp.387-392
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• 2007

Characteristics of needle morphology and anatomy were examined in 14 populations of Abies nephrolepis (Trautv.) Maxim. and A. koreana Wilson. Additionally we studied the classification index to distinguish between the species by the method of discriminant analysis. Characteristics of needle for A. nephrolepis could be distinguished from those for A. koreana by flatten arrangement, thin and long length for needle form, many stomata row, and marginal position of resin duct Nested ANOVA showed that there were statistically significant differences among populations as well as among individuals within populations in all 9 needle traits. For the needle indices such as needle thickness, number of stomata row, and the distance between resin duct and vascular for both species, variance components among populations were larger than those among individuals within populations. The characteristics that contributed most to the separation of A. nephrolepis and A. koreana according to the discriminant analysis using stepdisc procedures were needle index and thickness of needle, needle arrangement index, distance between resin duct and vascular, and number of stomata row.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.9-18
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• 2006

In the digital camera system, CMOS image sensor (CIS) is widely used because its size and weight become smaller and power consumption becomes lower. However, there are common problems that colors of the recorded image do not match those of the photographed object and that spectral sensitivity of the CIS used in different cameras varies largely in each case. Therefore, color correction is needed because the spectral sensitivity of the CIS in each color is neither the same color component for most standard colors nor the appropriate color representation for any output devices. In the conventional method, a color correction is empirically obtained by a large number of iterative experiments, but the result is not so satisfied. In this paper, a new method to obtain the efficient color correction matrix for digital camera using CIS is proposed. We obtain camera transfer matrix under the certain white-balance point, and color correction matrix that makes the transfer characteristic of digital camera close to the transfer characteristic of ideal camera is obtained. The experimental results show that the transfer characteristic of digital camera by the proposed method is close to that of the ideal camera. In addition, the image quality of pictures of digital camera using the proposed method is dramatically improved.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.817-820
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• 2008

The river environments of many streams in korea have been deteriorate through the rapid industrialization and urbanization since the 1960s. In korea, on the other hand, much efforts on the research and project have been made for the restoration of the deteriorated streams to close-to-nature. in order to restore the deteriorated streams, therefore, it is necessary to investigate such advanced technologies and materials. In view of this requirement, various research paths are being taken focusing on coarse aggregates to make multi-functional porous concrete having continuous voids so as to improve water and air permeability, acoustic absorption, water purification and applicability to vegetation. The Purpose of this study is to investigate the method for recovery of the environment in the streams area using porous concrete retaining wall block. the multi-P.O.C block applies for test in the Jangduri-cheon have been monitored planting, stability etc. after 6 months, plant grows flourishing and reconstructed in state such as nature rivers.

• Journal of IKEEE
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• v.18 no.2
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• pp.272-281
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• 2014

In electrical impedance tomography (EIT), modified Newton Raphson (mNR) method is widely used inverse algorithm for static image reconstruction due to its convergence speed and estimation accuracy. The unknown conductivity distribution is estimated iteratively by minimizing a cost functional such that the residual error namely the difference in measured and calculated voltages is reduced. Although, mNR method has good estimation performance, EIT inverse problem still suffers from ill-conditioned and ill-posedness nature. To mitigate the ill-posedness, generally, regularization methods are adopted. The inverse solution is highly dependent on the choice of regularization parameter. In most cases, the regularization parameter has a constant value and is chosen based on experience or trail and error approach. In situations, when the internal distribution changes or with high measurement noise, the solution does not get converged with the use of constant regularization parameter. Therefore, in this paper, in order to improve the image reconstruction performance, we propose a new scheme to determine the regularization parameter. The regularization parameter is computed based on residual error and updated every iteration. The proposed scheme is tested with numerical simulations and laboratory phantom experiments. The results show an improved reconstruction performance when using the proposed regularization scheme as compared to constant regularization scheme.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.57-68
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• 2002

The purpose of this study was to evaluate microleakage of etched and non-etched amalgam restorations lined with dentin bonding system primer and adhesives. Class V amalgam preparations were made in 100 extracted human premolars divided into 10 groups with 10 teeth each. SEM was taken to assess the dentin/amalgam interface. The results were as follows; 1. At the occlusal and gingival margins, all experimental groups showed lower leakage value than unlined group(p<0.05) The $Copalite^{(R)}-lined$ group showed higher leakage value than other experimental groups(p<0.05). 2. In all experimental groups, the gingival margin showed higher leakage value than the occlusal margin. 3. There were no significant difference between non-etching and etching groups, primer only and primer & adhesive groups, primer & adhesive and self-priming adhesive groups(p>0.05). 4. On the SEM observation, continuous gaps were observed in the unlined and $Copalite^{(R)}-lined$ groups, but the gaps were filled with primer or adhesive layer in other experimental groups.

• Korean journal of applied entomology
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• v.39 no.1
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• pp.43-52
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• 2000

A portion of mitochondria1 COI gene (438 bp) was sequenced from the sampls of Plutella xylostella from four localities in Korea to investigate the population genetic structure and characteristics by measuring the magnitude of genetic diversity and the degree of gene flow among populations. Thirteen haplotypes ranging in nucleotide divergence 0.3% to 1.4%, were obtained from 21 individuals. The nucleotide divergence was similar to the other related studies, but haplotype diversity was substantially higher (mean h = 0.81). The genetic distance among geographically remote Cheju Island population and the two Kimhae populations, distant 1 lkm to each other, was not statistically significant (p<0.05). Instead, a substantial or high female gene flow was detected (Nm = 2-30). One Hawaiian haplotype of the diamondback moth obtained through GenBank search also was genetically similar to the ones obtained from this study. Collectively, the genetic population structure of the diamondback moth in Korea can be characterized into two aspects. First, the diamondback moths in Korea possesses overall moderate genetic divergence based on a high number of haplotypes. Second, a high haplotype diversity within each population due to the long distance dispersal with a substantial dispersal power and the resultant genetic similarity among geographic populations is characteristic.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.17-22
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• 2000

A quaternary alloy film of $CoCr_{16.2}Pt_{10.8}Ta_4$was investigated for its magnetic properties and c-axis orientation with and without Ti underlayer. Additional elements such as Ta, Pt have been frequently introduced in CoCr alloy film for perpendicular recording as a means of improving magnetic performance. It has been reported that the addition of Pt and Ta in CoCr increase the coercivity and the magnetic isolation of columnar grains, respectively. However, CoCrPtTa perpendicular magnetic layer should be more increased its perpendicular magnetic anisotropy than at present for the application of ultrahigh recording density. The improvement of underlayers and substrate materials is one of the promised schemes to intensify the perpendicular magnetic anisotropy. In this study, the insertion of Ti underlayer shows the remarkable improvement of c-axis orientation compare with the direct deposition on the bare glass. The mechanism about this effect of Ti underlayer on CoCrPtTa is not to be clarified yet. Meanwhile, it is found that the magnetic domain of CoCrPtTa on 20 nm Ti underlayer has the continuous stripe pattern but the one of CoCrPtTa on 90 nm Ti underlayer shows the discrete mass type from the results of MFM investigation. This phenomenon is to be a distinct evidence that the improvement of perpendicular anisotropy by the adoption of Ti underlayer is originated from the reinforcement of the grain boundary segregation in CoCrPtTa alloy. Moreover, the transition of the M-H hysteresis pattern with the thickness of Ti underlayer indicates that the major contribution of Ti underlayer is not the magnetocrystalline anisotropy but the shape anisotropy due to the formation of uniform columnar grains by the nonmagnetic alloy segregation.

• Geotechnical Engineering
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• v.3 no.4
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• pp.41-54
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• 1987

A stochastic numerical analysis for predicting the groundswater fluctuations in hillside slopes is performed in this paper to account for the uncertainties associated with the rainfall and site characteristics. The effect of spatial variabilities of aquifer parameters and the effect of temporal variability of recharge on the groundwater fluctuations are studied in depth. The Kriging is used to account for the spatial tariabilities of aquifer parameters. This technique prolevides the best linear unbiased estimator of a parameter and its minimum variance from a litsitem number of measured data. A stochastic one-dimensional numerical model is delreloped b) combining the groundwater flow model, the Kriging, and the first-order second-moment analysis. In addition, a two dimensional detelministic groundwater model is developed to study the change of ground water surfas in the transverse direction as well as in the downslope direction. It is revealed that the undulations of the impervious bedrock in addition to the permeability and the specific yield have an important influence on the fluctuations of the groundwater surface. It is also found that th'e groundwater changes significantly in the transverse direction as well as in the downslope direction. The results obtained in this analysis may be used for evaluation of landslide risks due to high porewater pressure.