• Journal of Korean Tunnelling and Underground Space Association
• /
• v.6 no.4
• /
• pp.327-343
• /
• 2004

During tunnel construction, ground failures often occur due to existence of weak zones, such as faults, joints, and cavities, ahead of tunnel face. It is hard to detect effectively weak zones, which can lead underground structure to fail after excavation and before supporting, by using conventional characterization methods. In this study, an enhanced analytical method of predicting weak zones ahead of tunnel face is developed to overcome some problems in the conventional geophysical exploration methods. The analytical method is based on Coulomb's and Gauss' laws with considering the characteristics of electric fields subjected to rock mass. Using the developed method, closed form solutions are obtained to detect a spherical shaped zone and an oriented fault ahead of tunnel face respectively. The analytical results suggest that the presence of weak zones and their sizes, location, and states can be accurately predicted by combining a proper inversion process with resistance measured from several electrodes on the tunnel face. It appears that the skin depth or resistivity in rock mass is affected by the diameter of tunnel face, natural electric potential and noises induced by experimental measurement and spatial distribution of uncertain properties. The developed analytical solution is verified through experimental tests. About 1800 concrete blocks of 5cm by 5cm by 5cm in size are prepared and used to model a joint rock mass around tunnel face. Weak zones are simulated ahead of tunnel face with a material which has relatively higher conductivity than concrete blocks. Experimental results on the model test show a good agreement with analytical results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1785-1794
• /
• 2015

The purpose of this study is to examine differences between nursery teachers and kindergarten teachers in their perception on key elements of effective interactions and enhanced teaching competence. The subject of the study were 143 early childhood teachers in the Y region of Gyeonggi-do. The collected data was processed through frequency and percentage. For difference test, ${\chi}^2$ tests were conducted. The results of this study can be summarized as follows. First, both nursery teachers and kindergarten teachers perceived that listening and playing were the most important factors in effective interactions between young children and teachers. However, nursery teachers perceived the interaction through skin-ship and complimenting to be more important whereas kindergarten teachers perceived questioning and complimenting as necessary. For the teaching criteria, nursery teachers put more weights on playing while kindergarten teachers focus more on explaining and coorperating. In addition, about evaluation methods, nursery teachers perceived self-evaluation as important, whereas kindergarten teachers perceived observation notes as important. Second, about the elements to strengthen teaching competence, nursery teachers perceived that observation records should be utilized for understanding interest or desire. They also believe that development analysis and teaching methods should be improved through systematical teaching plan and evaluation and that enhancement of teaching material and education are necessary. In contrast, kindergarten teachers perceived that observation records should be utilized for teaching plan and development analysis and teaching methods should be improved through participating in the meetings related to career and education. They believe that providing a prize money through supervising evaluation is necessary.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.3
• /
• pp.469-479
• /
• 2015

This study is related to the developing method of a transparent sunscreen cosmetic which has waterproofing property and no white turbidity when applied to skin. The transparent sunscreen is prepared by exploiting refractive index difference between oil-phase and water-phase of water-in-oil(W/O) emulsion. The sunscreen according to this study is prepared as a W/O type emulsion so that it is water-stable and water resistance. Also, the stability of W/O type emulsion is developed by adjusting the content of oil phase part and water phase part. As a result of this studying, the transparent W/O emulsion is prepared by adjusting the refractive index of oil-phase and water-phase within 0.004 and it is found that the stability of the transparent sunscreen is increasing when the water phase part is over 75% (w/w) of the W/O emulsion. Through clinical test of transparent sunscreen, the value of sun protection Factor(SPF) and Protection Factor of UVA(PFA) were determined. SPF and PFA values of transparent sunscreen were indicated $30.99{\pm}1.65$ and $3.01{\pm}0.30$.

• Journal of Korea Multimedia Society
• /
• v.13 no.7
• /
• pp.1000-1015
• /
• 2010

In this paper, we propose a novel algorithm for hand gesture recognition. The hand detection method is based on human skin color, and we use the boundary energy information to locate the hand region accurately, then the moment method will be employed to locate the hand palm center. Hand gesture recognition can be separated into 2 step: firstly, the hand posture recognition: we employ the parallel NNs to deal with problem of hand posture recognition, pattern of a hand posture can be extracted by utilize the fitting ellipses method, which separates the detected hand region by 12 ellipses and calculates the white pixels rate in ellipse line. the pattern will be input to the NNs with 12 input nodes, the NNs contains 4 output nodes, each output node out a value within 0~1, the posture is then represented by composed of the 4 output codes. Secondly, the hand gesture tracking and recognition: we employed the Kalman filter to predict the position information of gesture to create the position sequence, distance relationship between positions will be used to confirm the gesture. The simulation have been performed on Windows XP to evaluate the efficiency of the algorithm, for recognizing the hand posture, we used 300 training images to train the recognizing machine and used 200 images to test the machine, the correct number is up to 194. And for testing the hand tracking recognition part, we make 1200 times gesture (each gesture 400 times), the total correct number is 1002 times. These results shows that the proposed gesture recognition algorithm can achieve an endurable job for detecting the hand and its' gesture.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.33 no.1 s.60
• /
• pp.53-60
• /
• 2007

(6R)-5,6,7,8-tetrahydrobiopterin ($6-BH_4$) cofactor is essential for various process, and is present in probably every cell or tissue of higher organism. $6-BH_4$ is required lot various enzyme activities, and for less defined functions at the cellular level. And it is well known about the antioxidant effects as a non-protein compound. Recently, scientists proposed another roles for $6-BH_4$ in melanogenesis. $6-BH_4$ is a well known tyrosinase inhibitor. In this study, we found that methyl-$BH_4$ and $6-BH_4$ have antioxidant activities and inhibitory activity for melanin synthesis. These pterin compounds were not toxic in HaCaT and B16F10 cells and showed scavenging activity against DPPH radicals. We also showed that pterin compounds decreased protein levels of tyrosinase and TRP-1. In a clinical test, pterin compounds showed the significant skin whiteining effect after treatment for 3 weeks. Furthermore pterin compounds significantly suppressed the UVB-induced expression of $PGE_2$ and IL-6 genes induced UVB In HaCaT and inhibited UVB-induced melanogenesis in B16F10 cells. These results showed the effect of pterin compounds as a cosmeceutical ingredient.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.40 no.2
• /
• pp.121-131
• /
• 2014

Due to the high UV light scattering effect of Zinc oxide (ZnO), it is frequently used in sunscreen skincare products. Recently ZnO coated with silica has been used in cosmetics to improve UV protection, texture, decreased photocatalytic activity, dispersibility and stability of the skin care product. In this study, we developed a ZnO composite powder coated with silica for the future application to skincare products to block UV rays that could cause photoaging. To improve consumer's satisfaction rating, we used ZnO microparticles which are widely used in the cosmetics industry. The silica was coated using hydrothermal method with sodium silicate and acid hydrolysis. UV protection of the composite powder was analyzed by UV-Vis and in-vitro test and the advantages for practical use of this powder as a skincare product were determined.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.43 no.1
• /
• pp.1-10
• /
• 2017

Cimicifuge dahurica (C. dahurica), Coptis chinensis (C. chinensis) and Phellodendri amurense (P. amurense) extracts has an detoxification effect and Magnol obovata bark (M. obovata) extracts has an antibacterial effect in oriental medicine. This study investigated the possibility of the extract mixture as a functional cosmetic ingredient by mixing C. dahurica, C. chinensis, P. amurense and M. obovata extracts. MTT assay was carried out for toxicity test and DPPH/ABTS experiments for antioxidant effects of the extract mixture. Results show that the extract mixture was safer and antioxidant effects in a dose-dependent manner than single extract of the mixture. The mixture effectively inhibited NO (nitric oxide) production, which indicate good efficacy for anti-inflammation. The mixture also protected UVB-induced cell damage and increased type 1 pro-collagen synthesis in fibroblast. In addition, it's treatment inhibited the melanin synthesis and tyrosinase activity by lowering expression of MITF, tyrosinase and TRPs in B16F10 melanoma cell. These results suggest that medicinal herbal extract mixture may be useful as a functional ingredient for anti-aging and skin whitening cosmetic formula.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.31 no.3
• /
• pp.39-49
• /
• 2018

Objectives : This study is designed to clarify whitening, anti-inflammatory effect of fractions extracted from the mixture of Phaseolus radiatus L. and ethanol. Methods : In this experiment, we were intended to reveal whitening, anti-inflammatory effect of fractions extracted from the mixture of Phaseolus radiatus L. and ethanol. The whitening activity was confirmed by UV blocking activity, tyrosinase inhibiting activity, and melanin formation inhibiting activity. Anti-inflammatory activity is confirmed by measurement of cytotoxicity level by MTT assay and measurement of Cytokine expression, which is the main mediator of inflammation reaction. Results : As a results, overall activity was high in the ethyl acetate fraction. Tyrosinase inhibitory activity was less than 20% at all concentrations, but the activity to inhibit melanin self-production was higher than that of ethyl acetate fraction at $32.19{\pm}2.79%$ at $100{\mu}g/m{\ell}$. And ethyl acetate fraction had a relatively high UV blocking activity. In the anti-inflammatory test, the concentration-dependent activity was shown, and the chloroform and ethyl acetate fractions showed significant NO production inhibitory activity. Cytokine expression was superior to that of the final stage of B cell differentiation, and cell viability was over 80% except for the chloroform fraction at the concentration of $200{\mu}g/m{\ell}$. Conclusions : The results of this experiment confirmed the whitening effect and anti-inflammatory effect of Phaseolus radiatus L.'s extracts and fractions and report the possibility of application as external medicine.

• Korean Journal of Clinical Pharmacy
• /
• v.20 no.3
• /
• pp.255-261
• /
• 2010

Cefprozil is a broad-spectrum oral beta-lactam cephalosporin consisting of cis- and trans-isomeric mixture whose ratio is approximately 90:10. Cefprozil is used to treat certain infections caused by bacteria such as bronchitis and ear, skin, and throat infections. The purpose of the present study was to evaluate the bioequivalence of two cefprozil tablets, $Cefzil^{(R)}$ tablet 250 mg (BMS Pharmaceutical Korea., Ltd.) and Procezil tablet 250 mg (Hanmi Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The in vitro release of cefprozil from the two cefprozil formulations were tested using KP VIII Apparatus I method with water dissolution media. Thirty five healthy male subjects, $24.00{\pm}1.53$ years in age and $69.77{\pm}9.99$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After four tablets containing 1000 mg as cefprozil were orally administered, blood samples were taken at predetermined time intervals and the concentrations of cefprozil in serum were determined using HPLC/UV detector. The dissolution profiles of two formulations were similar in water tested dissolution media. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ on the basis of total-cefprozil were calculated, and computer program (K-BE Test 2002) was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, $Cefzil^{(R)}$ tablets, were -0.81%, -3.00% and -6.83% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., log 0.9515~log 1.0454 and log 0.9613~log 1.0465 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Procezil tablet was bioequivalent to $Cefzil^{(R)}$ tablet.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.6
• /
• pp.387-395
• /
• 2003

Model tests were conducted to study the behavior of the piled raft foundation system on sands. Especially in this study, the method using the triaxial compression apparatus was devised and used to apply the confining pressure which is considered difficult in the existing model test on the soil. Steel rods (6mm dia.) and aluminum plates (8mm thickness, 50mm dia.) were used to simulate piles and rafts respectively. Jumunjin standard sands were used to ensure the homogeneity of the sample. After the sample with the piled raft model was laid inside the triaxial cell, the confining pressure was applied and then the compressive force was applied. The increase and/or decrease ratio of the bearing capacity, the load distribution ratio between raft and piles and the effect of settlements decrease depending on the confining pressure, the number of piles and the length of piles were analyzed and the bearing capacity and skin friction of the pile was calculated. By the results of these experiments, the bearing capacity increased and the settlement decreased with this piled raft foundation system. Especially the effect was larger with the increase of the number of piles than with the increase of length of piles. Hereafter, the study of the load transfer mechanism of piles under confining pressure would be made possible using these small model tester like triaxial compression apparatus.