• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.343-347
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• 2005

As aging occurs, ow skin gets more wrinkles, becomes drier and loses its elasticity. Validating the evaluation of skin elasticity is especially important, because it is not as visible as other signs of aging such as wrinkles. Here, we identified the correlation between age and the Parameters given by Cutometer, and (we present) the parameters of that reflect the decreases in skin elasticity along with ages (Ur/Uf, Ua/Uf, Ur/Ue, Ua, $r=0.687{\sim}0.725$). Also we developed an evaluation method to quantify the difference of skin by viewing or touching. A five-grade standard of Moire topographic photo scale on face was prepared using sensory evaluation of 20 to 61 year - old women. Based on this photo standard, scoring was performed using (a) 5-grade system by three specialists to obtain the consensus score. Significant negative correlations between age and results of Cutometer $(r=-0.687{\sim}-0.725)$, Moire topography scores (r=-938) were found. Finally we have shown the significance of the correlation between the result of Cutometer and the score of Moire topography (r=0.711). Our studies using Moire topography on face have confirmed that instrumental measurements reflect the decrease in shin elasticity, which is perceived visually.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.145-151
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• 1997

The R&D investment of power industry has significant influences on the social welfare as well as national economy. It is necessary to analyze how efficient the R&D investment has been performed. The objective of this study is to verify the efficiency of the R&D investment in the domestic power industry. A formula was introduced to by calculate the appropriate amount of R&D investment of monopolistic industry under the regulations which are determined by the proportion of R&D elasticity and price elasticity. It has resulted that there would be no economy of scale as the sales of electricity increases at the same rate of the increasing cost. The R&D investment in the present electricity industry has been performed inefficiently by showing the negative impact on price-cost margin of the intensity of R&D investment, which is the extent of R&D investment to reinforce economy of scale.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.184-193
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• 2021

This paper investigates the performance of technology innovation activities performed by firms in 16 major regions in Korea using 2002-2010 survey data by STEPI. The theoretical and empirical analysis is carried out via the 2 models which are the simple R&D - total revenue model and Cobb-Douglas model based on the simple model adding labor variable. The main results shows that for simple model, the R&D elasticity for total revenue is 0.42 for all areas and Ul-San shows the highest elasticity level, 0.66 and Bu-San the lowest level, 0.2. In case of Cobb Douglas model the R&D elasticities are not statistically significant for many regions. To overcome the low statistical significance, we grouped the 15 regions for 3 wider regions using ANOVA based on the R&D intensity for the homogeneity of R&D activities. By grouping, each region has more observations to analyze and the results from the empirical analysis shows higher statistical significance level and data explanation capability. In this case, Group 3 which shows larger firm size and slightly higher export share shows the highest level of R&D elasticity, 0.088 and Group 1 which has the smallest firm size and the lowest revenue growth rate shows the lowest level, 0.31. For the labor elasticity, Group 1 shows the higest level, 1.16 and Group2 the lowest level, 1.096. These results show that the regions which have many middle and small firms reveal low R&D-revenue elasticity and high labor-revenue elasticity.

• Steel and Composite Structures
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• v.27 no.2
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• pp.201-216
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• 2018

In this paper, three-dimensional (3D) elasticity theory in conjunction with nonlocal strain gradient theory (NSGT) is developed for mechanical analysis of anisotropic nanoparticles. The present model incorporates two scale coefficients to examine the mechanical characteristics much accurately. All the elastic constants are considered and assumed to be the functions of (r, ${\theta}$, ${\varphi}$), so all kind of anisotropic structures can be modeled. Moreover, all types of functionally graded spherical structures can be investigated. To justify our model, our results for the radial vibration of spherical nanoparticles are compared with experimental results available in the literature and great agreement is achieved. Next, several examples of the radial vibration and wave propagation in spherical nanoparticles including nonlocal strain gradient parameters are presented for more than 10 different anisotropic nanoparticles. From the best knowledge of authors, it is the first time that 3D elasticity theory and NSGT are used together with no approximation to derive the governing equations in the spherical coordinate. Moreover, up to now, the NSGT has not been used for spherical anisotropic nanoparticles. It is also the first time that all the 36 elastic constants as functions of (r, ${\theta}$, ${\varphi}$) are considered for anisotropic and functionally graded nanostructures including size effects. According to the lack of any common approximations in the displacement field or in elastic constant, present theory can be assumed as a benchmark for future works.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.25 no.3
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• pp.150-159
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• 2012

Objective : The purpose of this study was to evaluate the effect of korean herbal cosmetics for facial skin elasticity. Methods : We recruited patients and divided them to cosmetics group and control group randomly. We provided korean herbal cosmetics to cosmetics group and subjects in cosmetics group applied the provided cosmetics for 4 weeks. Control group waited and applied cosmetics that had previously used for 4 weeks. We assessed all subjects in 0 week, 2 weeks and 4 weeks. Primary assessment instrument was moire topography photo scale. Second assessment instrument was skin moisture, oiliness and elasticity which assessed with skintouch system v1.0, detox/regeneration questionnaire score and self-evaluating facial wrinkle/looseness score. Result : Moire topography photo scale improved in cosmetics group than control group significantly. Skin moisture and elasticity assessed with skintouch system improved in cosmetics group than control group significantly while skin oiliness assessed with skintouch system have not improved significantly. Detox/regeneration questionnaire score and self-evaluating facial wrinkle/looseness score improved in cosmetics group than control group significantly. Conclusion : Korean herbal cosmetics application might be effective method for facial skin elasticity.

• Steel and Composite Structures
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• v.28 no.1
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• pp.13-24
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• 2018

A size-dependent novel hyperbolic shear deformation theory of simply supported functionally graded beams is presented in the frame work of the non-local strain gradient theory, in which the stress accounts for only the nonlocal strain gradients stress field. The thickness stretching effect (${\varepsilon}_z{\neq}0$) is also considered here. Elastic coefficients and length scale parameter are assumed to vary in the thickness direction of functionally graded beams according to power-law form. The governing equations are derived using the Hamilton principle. The closed-form solutions for exact critical buckling loads of nonlocal strain gradient functionally graded beams are obtained using Navier's method. The derived results are compared with those of strain gradient theory.

• Advances in nano research
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• v.7 no.3
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• pp.191-208
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• 2019

In the present work the dynamic analysis of the functionally graded rectangular nanoplates is studied. The theory of nonlocal elasticity based on the quasi 3D high shear deformation theory (quasi 3D HSDT) has been employed to determine the natural frequencies of the nanosize FG plate. In HSDT a cubic function is employed in terms of thickness coordinate to introduce the influence of transverse shear deformation and stretching thickness. The theory of nonlocal elasticity is utilized to examine the impact of the small scale on the natural frequency of the FG rectangular nanoplate. The equations of motion are deduced by implementing Hamilton's principle. To demonstrate the accuracy of the proposed method, the calculated results in specific cases are compared and examined with available results in the literature and a good agreement is observed. Finally, the influence of the various parameters such as the nonlocal coefficient, the material indexes, the aspect ratio, and the thickness to length ratio on the dynamic properties of the FG nanoplates is illustrated and discussed in detail.

• Ocean Systems Engineering
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• v.1 no.4
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• pp.285-296
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• 2011

Spar platforms have several advantages for deploying wind turbines in offshore for depth beyond 120 m. The merit of spar platform is large range of topside payloads, favourable motions compared to other floating structures and minimum hull/deck interface. The main objective of this paper is to present the response analysis of the slack moored spar platform supporting 5MW wind turbine with bottom keel plates in regular and random waves, studied experimentally and numerically. A 1:100 scale model of the spar with sparD, sparCD and sparSD configuration was studied in the wave basin ($30{\times}30{\times}3m$) in Ocean engineering department in IIT Madras. In present study the effect of wind loading, blade dynamics and control, and tower elasticity are not considered. This paper presents the details of the studies carried out on a 16 m diameter and 100 m long spar buoy supporting a 90 m tall 5 MW wind turbine with 3600 kN weight of Nacelle and Rotor and 3500 kN weight of tower. The weight of the ballast and the draft of the spar are adjusted in such a way to keep the centre of gravity below the centre of buoyancy. The mooring lines are divided into four groups, each of which has four lines. The studies were carried out in regular and random waves. The operational significant wave height of 2.5 m and 10 s wave period and survival significant wave height of 6 m and 18 s wave period in 300 m water depth are considered. The wind speed corresponding to the operational wave height is about 22 knots and this wind speed is considered to be operating wind speed for turbines. The heave and surge accelerations at the top of spar platform were measured and are used for calculating the response. The geometric modeling of spar was carried out using Multisurf and this was directly exported to WAMIT for subsequent hydrodynamic and mooring system analysis. The numerical results were compared with experimental results and the comparison was found to be good. Parametric study was carried out to find out the effect of shape, size and spacing of keel plate and from the results obtained from present work ,it is recommended to use circular keel plate instead of square plate.