• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1231-1245
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• 2015

People have transferred their business model from traditional commerce to e-commerce in recent decades. Both shopping and payment can be completed through the Internet and bring convenience to consumers and business opportunities to industry. These trade techniques are mostly set up based on the Secure Sockets Layer (SSL). SSL provides the security for transaction information and is easy to set up, which makes it is widely accepted by individuals. Although attackers cannot obtain the real content even when the transferred information is intercepted, still there is risk for online trade. For example, it is impossible to prevent credit card information from being stolen by virtual merchant. Therefore, we propose a new mechanism to solve such security problem. We make use of the disposable dynamic security code (DSC) to replace traditional card security code. So even attackers get DSC for that round of transaction, they cannot use it for the next time. Besides, we apply visual secret sharing techniques to transfer the DSC, so that interceptors cannot retrieve the real DSC even for one round of trade. This way, we can improve security of credit card transaction and reliability of online business. The experiments results validate the applicability and efficiency of the proposed mechanism.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.534-542
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• 1994

Microstructures and dielectric properties of (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.006Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramic were investigated. The specimens fired in a reducing atmosphere(N$_{2}$) were painted on the surface with CuO paste, and then annealed at 1100.deg. C for 2 hr. SEM and EDAX revealed that CuO penetrated rapidly into the bulk along the grain boundaries during the annealing. Grain size increased with increasing Ca content up to 15[mol%], but decreased with further addition. In the specimens with 10-15[mol%l of Ca, excellent dielectric properties were obtained as follows; dielectric constant <25000, dielectric loss(tan .delta[%]) <0.3[%] and capacitance change rate with temperature <.+-.[%], respectively. All the specimens in this study exhibited dielectric relaxation with frequency as a function of the temperature. The dispersive frequency was over 10$^{6}$ [Hz].z].

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.1-8
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• 2015

This study was designed to determine the antioxidant activity of solvent fractions of broccoli sprouts grown by controlling the growing environment at the plant factory system. Fractionation was achieved with chloroform, n-hexane, ethyl acetate, butanol, water by 70% EtOH extract of the broccoli sprouts. Each solvent fraction was put through TLC and HPLC to separate active components. Higher antioxidant activities were observed for the butanol and ethyl acetate layers. Further evaluation of each of the 5 layers (LH1 to LH5) of the butanol fraction showed that the refined LH3 extract had a high antioxidant effect. Components with similar Rf values from TLC had the same retention times and peaks in the HPLC analysis. It was also determined that the sulforaphane content was high at the chloroform and butanol layers and the sulforaphane was responsible for, the high antioxidant activity. Thus, to use for functional materials, the butanol extract/layer of broccoli sprouts is recommended as the most effective.

• Korean Journal of Materials Research
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• v.14 no.7
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• pp.462-469
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• 2004

The effect of Cu addition on the corrosion characteristics of Zr alloys that developed for nuclear fuel cladding in KAERI (Korea Atomic Energy Research Institute) was evaluated. The alloys having different element of Nb, Sn, Fe, Cr and Cu were manufactured and the corrosion tests of the alloys were performed in static autoclave at $360^{\circ}C$, distilled water condition. The alloys were also examined for their microstructures using the optical microscope and the TEM equipped with EDS and the oxide property was characterized by using X-ray diffraction. From the result of corrosion test more than 450 days, the corrosion rate of the Zr-based alloys was changed with alloying element such as Nb, Sn, Fe, Cr and especially affected by Cu addition. The corrosion resistance was increased with increasing the Cu content and the tetragonal $ZrO_2$ layer was more stabilized on the Cu-containing alloys.

• Laser Solutions
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• v.13 no.3
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• pp.1-6
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• 2010

The in-process monitoring of $CO_2$ welding of Zn-coated steel plates has been studied and compared with that of conventional thin plates. Relationships between weld defects and plasma emission signals were evaluated in laser lap joint of thick Zn-coated steel. According to the study, weld defects were found to increase with Zn content. As a result, measured plasma emission signals also decreased. In case of plate with $15{\mu}m$-thick Zn-coated layer, defects caused by evaporation of Zn could, therfore, controled by gap of 0.1mm, resulting in a stable emission signals. However, the amplitude of signals fluctuated very widely. Variation of amplitude sould be limited in 3-8V by FFT smoothing.

• Atmosphere
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• v.20 no.4
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• pp.427-436
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• 2010

The single-scattering optical properties of ice crystals in cirrus clouds by the aircraft measurement data were investigated, and the radiative equilibrium temperatures and radiative fluxes were calculated and analyzed by radiative convective model with the variations of ice crystal habits and sizes in cirrus clouds. The homogeneous cloud is assumed to be in the layer 200~260 hPa with an ice crystal content of $10gm^{-2}$ for the flux calculation. The profiles of temperature, humidity, and ozone typical of mid-latitude summer are used. The surface albedo is assumed to be 0.2 for all spectral bands and the cosine of solar zenith angles is 0.5. The result of radiative equilibrium temperature at surface was less than surface temperature of the standard atmosphere data in case of smaller effective ice crystal size and larger optical thickness. The column, aggregation and plate in 6 ice crystal habits were the most effective in positive greenhouse effect and bullet-4 was the worst in it. At the surface, the maximum difference of equilibrium temperature by 6 kinds of ice crystal habits were about 3~15 K with 30 sample aircraft measurement data.

• Journal of the Korean Society of Combustion
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• v.10 no.1
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• pp.20-26
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• 2005

In the present study, catalytic combustion of hydrogen-air premixture in a millimeter scale monolith coated with Pt catalyst was investigated. As the combustor size decreases, the heat loss increases in proportion with the inverse of the scale of combustion chamber and combustion efficiency decreases in a conventional type of combustor. Combustion reaction assisted by catalyst can reduce the heat loss by decreasing the reaction temperature at which catalytic conversion takes place. Another advantage of catalytic combustion is that ignition is not required. Platinum was coated by incipient wetness method on a millimeter scale monolith with cell size of $1{\times}1mm$. Using this monolith as the core of the reaction chamber, temperatures were recorded at various locations along the flow direction. Burnt gas was passed to a gas chromatography system to measure the hydrogen content after the reaction. The measurements were made at various volume flow rate of the fuel-air premixture. The gas chromatography results showed the reaction was complete at all the test conditions and the reacting species penetrated the laminar boundary layer at the honeycomb and made contact with the catalyst coated surface. At all the measuring locations, the record showed monotonous increase of temperature during the measurement duration. And the temperature profile showed that the peak temperature is reached at the point nearest to the gas inlet and decreasing temperature along the flow direction.

• Journal of Pharmaceutical Investigation
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• v.26 no.2
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• pp.99-103
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• 1996

Effects of glycerin and PEG 400 in donor and receptor solutions upon skin permeation of drug were investigated. Deoxycortisone was used as a model compound. In vitro skin permeation study with freshly excised hairless mouse skin was performed and the steady-state skin permeation rates of the drug were determined in different fractions of glycerin or PEG 400 in donor and receptor solutions. Glycerin in donor solution didn't show any effect on the skin permeation rate of deoxycortisone. However glycerin in receptor solution showed significant effect on the skin permeation rate of the drug. In glycerin, there's a critical concentration for balancing hydration and dehydration of skin. At low concentration, less than 20 %, glycerin showed the enhancement of the flux due to the hydration effect of skin. At high concentration, more than 30 %, glycerin retard the permeation rate which might be due to the dehydration effect on the dermis layer. Since dermis has more water content than the stratum corneum, the steady state skin permeation rates were more influenced when glycerin was in receptor solution than that of in donor solution. PEG 400 aqueous solutions doesn't affect the steady state permeation rate of deoxycortisone significantly.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.239-244
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• 1998

Dried carrot meal (DCM) prepared from fresh carrot was found to be a good source of xanthophyll (54 mg/kg) and morderate source of protein (188.3 g/kg) and energy (2,510 kcal/kg) with low level of fibre (80 g/kg). DM, EE and NFE content of DCM were 895, 35 and 661.7 g/kg respectively. The ingredient was used in laying hen diet to evaluate its pigmenting value for egg yolk. Thirty-two laying hens from Starcross strain were divided into four groups and fed four different diets: a control diet containing 62% ground wheat, a corn-based diet (50% ground yellow corn), control + 4% DCM and control + 8% DCM. Use of DCM at 8% level in layer mash significantly improved yolk colour at 3rd, 6th and 9th week of supplementation in comparison with wheat-based control diet. This improvement was statististically similar to that obtained from yellow corn-based diet. DCM at 4% level also improved yolk colour score. Wheat-based diet significantly increased feed consumption compared to yellow corn and diet supplied with 8% DCM. Body weight gain, egg production, feed conversion were not significantly affected due to dietary addition of DCM and no mortality was observed during 63-day experimental period. Further works on DCM are suggested.

• Environmental Engineering Research
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• v.18 no.3
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• pp.129-137
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• 2013

The infiltration of rainwater into the surface soil is highly dependent on hydraulic variables, such as the infiltration rate, capillary fringe, moisture content, and unsaturated/saturated hydraulic conductivity. This study estimates the hydraulic conductivity (K) of fluvial deposits at three sites on the right and left banks of Nakdong River in Gyeongbuk Province, South Korea, including the Gumi, Waegwan, and Seongju bridge sites. The K values of 80 samples from 13 boreholes were estimated by using six grain-size methods (Hazen, Slichter, Kozeny, Beyer, Sauerbrei, and Pavchich formulae). The Beyer, Hazen, and Slichter methods showed a better relationship with K values along with an effective grain size than did the other three methods. The grain-size, pumping test, and slug test analyses resulted in different K values, but with similar K values in the grain-size analysis and pumping test. The lower K values of the slug test represent the uppermost fine sand layer.