• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.486-491
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• 2014

In this paper, the adsorption behavior and kinetic characteristics of cibacron brilliant red 3B-A from aqueous solution using granular activated carbon were investigated. The effect of various parameters such as adsorbent dose, pH, initial concentration, contact time and temperature on the adsorption system were studied. Base on the estimated Langmuir constant ($R_L$) and Freundlich constant (1/n), This process could be employed as effective treatment method. From the Temkin constant (B) and Dubinin-Radushkevich constant (E), This adsorption process is physical adsorption. From kinetic experiments, the adsorption process followed the pseudo second order model with good correlation. Base on the Gibbs free energy and enthalpy, the adsorption of cibacron brilliant red 3B-A onto granular activated carbon was physisorption and endothermic in nature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.557-562
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• 2006

In order to predict the dispersion of suspended sediment arising from dredging operation in port and navigation channel, a hybrid model for dispersive transport of turbidity plume was developed using Lee's(1998) hybrid method. Using hybrid modeling scheme advection-diffusion equation was solved by the forward particle-tracking method for advection process and by the fixed Eulerian grid method for diffusion process. To examine numerical model simulation in accuracy, the simulated results for 1-D, 2-D, and 3-D cases were compared with the analytical solutions including Kuo, et al's (1985) 3-D mathematical model. The model results were in a good agreement with the analytical solutions and mathematical model for the dispersion of turbidity plume.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.357-366
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• 2015

This study was conducted to estimate carbon stocks of Quercus serrata with drawing volume of trees in each tree height and DBH applying the suitable stem taper equation and tree specific carbon emission factors, using collected growth data from all over the country. Information on distribution area, tree number per hectare, tree volume and volume stocks were obtained from the $5^{th}$ National Forest Inventory (2006~2010), and method provided in IPCC GPG was applied to estimate carbon storage and removals. Performance in predicting stem diameter at a specific point along a stem in Quercus serrata by applying Kozak's model,$d=a_1DBH^{a_2}a_3^{DBH}X^{b_1Z^2+b_2ln(Z+0.001)+b_3{\sqrt{Z}}+b_4e^Z+b_5({\frac{DBH}{H}})}$, which is well known equation in stem taper estimation, was evaluated with validations statistics, Fitness Index, Bias and Standard Error of Bias. Consequently, Kozak's model turned out to be suitable in all validations statistics. Stem volume tables of Quercus serrata were derived by applying Kozak's model and carbon stock tables in each tree height and DBH were developed with country-specific carbon emission factors ($WD=0.65t/m^3$, BEF=1.55, R=0.43) of Quercus serrata. As a result of carbon stock analysis by age class in Quercus serrata, carbon stocks of IV age class (11,358 ha, 36.5%) and V age class (10,432; 33.5%) which take up the largest area in distribution of age class were 957,000 tC and 1,312,000 tC. Total carbon stocks of Quercus serrata were 3,191,000 tC which is 3% compared with total percentage of broad-leaved forest and carbon sequestration per hectare(ha) was 3.8 tC/ha/yr, $13.9tCO_2/ha/yr$, respectively.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.4
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• pp.16-22
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• 2012

In this paper, the forensic marking algorithm is proposed using psychoacoustic model II and MDCT for high-quality audio. The proposed forensic marking method, that inserts the user fingerprinting code of the audio content into the selected sub-band, in which audio signal energy is lower than the spectrum masking level. In the range of the one frame which has 2,048 samples for FFT of original audio signal, the audio forensic marking is processed in 3 sub-bands. According to the average attack of the fingerprinting codes, one frame's SNR is measured on 100% trace ratio of the collusion codes. When the lower strength 0.1 of the inserted fingerprinting code, SNR is 38.44dB. And in case, the added strength 0.5 of white gaussian noise, SNR is 19.09dB. As a result, it confirms that the proposed audio forensic marking algorithm is maintained the marking robustness of the fingerprinting code and the audio high-quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2985-2991
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• 2013

Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.437-450
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• 1996

A set of stability equations is formulated for natural convection flows adjacent to a vertical isothermal surface melting in cold pure water. It takes account of the nonparallelism of the base flows. The melting rate is regarded as a blowing velocity at the ice surface. The numerical solutions of the linear stability equations which constitute a two-point boundary value problem are accurately obtained for various values of the density extremum parameter $R=(T_m-T_{\infty})/(T_0-T_{\infty})$ in the range $0.3{\leq}R{\leq}0.6$, by using a computer code COLNEW. The blowing effects on the base flow becomes more significant as ambient temperature ($T_{\infty}$) increases to $T_{\infty}=10^{\circ}C$. The maximum decrease of heat transfer rate is about 6.4 percent. The stability results show that the melting at surface causes the critical Grashof number $G^*$ and the maximum frequency of disturbances to decrease. In comparision with the results for the conventional parallel flow model, the nonparallel flow model has a higher critical Grashof number but has lower amplification rates of disturbances than does the parallel flow model. The spatial amplification contours exhibit that the selective frequency $B_0$ of the nonparallel flow model is higher than that of the parallel flow model and that the effects of melting are rather small. The present study also indicates that the selective frequency $B_0$ can be easily predicted by the value of the frequency parameter $B^*$ at $G^*$, which comes from the neutral stability results of the nonparallel flow model.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.451-459
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• 2024

Recently, the size of the online education service market has been growing, but the B2C platform education service market, where companies take the lead in creating content and consumers consume the content, has become widespread. This makes content creation rigid and may have limitations in creating at various levels. This Study newly establishes the concept and type of customer needs, wants, innovation, and platform business, and presents new start-up success factors in all fields of platform business start-up and a standard diagnostic process for the possibility of platform start-up success. Through the presented process, customers, core activities, and value proposition factors can be derived. Finally, a business model for starting a C2C platform for elementary, middle, and high school education is built centered on the business model canvas.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.356-372
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• 2004

Statement of problom: In the internal connection system the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. Purpose: The purpose of this study was to assess the loading distributing characteristics of 3 implant systems with internal connection under vertical and inclined loading using finite element analysis. Material and method: Three finite element models were designed according to the type of internal connection of ITI(model 1), Friadent(model 2), and Bicon(model 3) respectively. This study simulated loads of 200N in a vertical direction (A), a $15^{\circ}$ inward inclined direction (B), and a $30^{\circ}$ outward inclined direction (C). Result: The following results have been made based on this numeric simulations. 1. The greatest stress showed in the loading condition C of the inclined load with outside point from the centric cusp tip. 2. Without regard to the loading condition, the magnitudes of the stresses taken at the supporting bone, the implant fixture, and the abutment were greater in the order of model 2, model 1, and model 3. 3. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture, and lower stress was taken at the cancellous bone. 4. The stress of the implant fixture was usually widely distributed along the inner surface of the implant fixture contacting the abutment post. 5. The stress distribution pattern of the abutment showed that the great stress was usually concentrated at the neck of the abutment and the abutment post, and the stress was also distributed toward the lower part of the abutment post in case of the loading condition B, C of the inclined load. 6. In case of the loading condition B, C of the inclined load, the maximum von Misess stress at the whole was taken at the implant fixture both in the model 1 and model 2, and at the abutment in the model 3. 7. The stress was inclined to be distributed from abutment post to fixture in case of the internal connection system. Conclusion: The internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, and the abutment according to the abutment connection form had differenence among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the a butment post.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.187-193
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• 2001

This paper is results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.280-293
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• 1998

Numerical study on turbulent and mean structures of a turbulent boundary layer with longitudinal and spanwise pressure gradient is carried out by using Reynolds-stress-model (RSM). The existence of pressure gradient in a turbulent boundary layer causes the skewing or divergence of rates of strain, which contributes to production of turbulent kinetic energy. Also, this augmentation of production due to extra rates of strain can increase the turbulent mixing and cause the anisotropy of turbulent intensities in the outer layer. This paper uses the Reynolds Stress Model to capture anisotropy of turbulent structures effectively and is devoted to compare the results computed by using RSM and the standard k-.epsilon. model with experimental data. It is concluded that the RSM can produce the more accurate predictions for capturing the anisotropy of turbulent structure than the standard k-.epsilon. model.