• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.107-116
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• 2005

Objectives : We analyzed the changes from 1996 to 2002 in distributive equity of the contribution burden in the Korean National Health Insurance. Methods : The study subjects were a total of 8,923 employee households and a total of 7,296 self-employed households over the period from 1996 to 2002. Those were the households meeting the two criteria as completing each annual survey and having no change in the job of head of the household during that period from the raw data of the Household Income and Expenditure Survey annually conducted by the Korean National Statistical Office. The unit of analysis was a household, and this was the standard for assessing the contribution that is now applied on a monthly basis. Deciles Distribution Ratio, Contribution Concentration Curve and Contribution Concentration Index were estimated as the index of inequality. Multiple regression analysis was conducted to compare the annual ability-to-pay elasticity of the contribution to the reference year of 1996 for three groups (all households, the employee households, and the self-employed households). Results : For the index of inequality, the distributive equity of contribution was improved in all three groups. In particular, the employee group experienced a substantial improvement. Using multiple regression analysis, the ability-to-pay elasticity of the contribution in the employee group significantly increased ($\beta$=0.232, p<0.0001) in the year 2002 as compared to the reference year of 1996. The elasticity in the self-employed group also significantly increased ($\beta$=0.186, p<0.05), although its change was smaller than that in the employee group. Conclusions : The employee group had a greater improvement for the distributive equity of the contribution burden than the self-employed group. Within the observation period, there were two important integration reforms: one was the integration of 227 self-employed societies in 1998 and the other was the integration of 139 employee societies in 2000. We expected that the equity of the contribution burden would be improved for the self-employed group since the integration reform of 1998. However, it was not improved for the self-employed group until the year 2000. This result suggests that capturing exactly the beneficiaries' ability-to-pay such as income is the precedent for distributive equity of the contribution burden, although a more sophisticated imposition standard of contribution is needed.

• The Journal of Korean Medicine
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• v.27 no.2 s.66
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• pp.145-154
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• 2006

Objectives : Methods to evaluate obesity are growing to be important in studying links between health and disease. Physicians are using BMI (body mass index) to evaluate obesity, but they can't know how much fat the body has by using that method. Even though there are several assessments, there are different scales, so patients are diagnosed as obese, by some but not by others. These studies are limited in evaluating obesity; it is necessary to study based on new knowledge. According to Oriental Medical Theory, obese people are categorized into 3 types, Fei, Kao and Liu Ren. They have different pathology and body shapes than non-obese people. The relationship between Oriental Medical Theory and BMI and assessment of body fat is a fundamental need to easily approach and treat obesity. Methods : At 00 Oriental Medical Center, 145 female subjects who intended to lose weight were given physical tests and grouped into 5 types of obesity. The physical tests were height measurement, BMI, body composition (body fat mass and lean body mass), skin elasticity and physical strength tests. One-way analysis of variance was done to compare the means of physical tests between the five types of obese women. There was some relationship between characteristics of the five types based on physical tests and Fei, Kao and Liu Ren based on Oriental Medical Theory. Least significant difference (LSD) was used in multiple comparisons. Results : 1. According to the skin elasticity test, obesity type 5 placed between obesity types 3 and 4 and obesity types 1 and 2. Obesity types 3 and 4 were in the low skin elasticity result group; obesity types 1 and 2 were in the high ones (p<0.1).Based on Oriental Medical Theory, Fei Ren and Kao Ren can be distinguished by skin elasticity degree. This result should form the basis of obesity diagnosis. 2. According to Oriental Medical Theory, Fei Ren is smaller than others. Based on height measurement, obesity types 3 and 4 were significantly lower than other obesity types (p<0.1), so there is a relationship between Fei Ren and obesity types 3 & 4. 3. There were significant differences between obesity type 2 and obesity type 4 in the body fat mass result (p<0.1). This study did not have large enough a sample size to distinguish Liu Ren. Conclusions : Further clinical research is necessary to study measurement methods of body shape type and skin elasticity for distinguishing Fei Ren from Kao Ren. The diagnosis and treatment based on the relationship of these types should be studied further.

• The Journal of the Acoustical Society of Korea
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• v.42 no.5
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• pp.403-411
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• 2023

Functional ultrasound imaging, such as elasticity imaging and micro-blood flow Doppler imaging, enhances diagnostic capability by providing useful mechanical and functional information about tissues. However, the implementation of functional ultrasound imaging poses limitations such as the storage of vast amounts of data in Radio Frequency (RF) data acquisition and processing. In this paper, we propose a sub-Nyquist approach that reduces the amount of acquired axial samples for efficient shear-wave elasticity imaging. The proposed method acquires data at a sampling rate one-third lower than the conventional Nyquist sampling rate and tracks shear-wave signals through RF signals reconstructed using band-pass filtering-based interpolation. In this approach, the RF signal is assumed to have a fractional bandwidth of 67 %. To validate the approach, we reconstruct the shear-wave velocity images using shear-wave tracking data obtained by conventional and proposed approaches, and compare the group velocity, contrast-to-noise ratio, and structural similarity index measurement. We qualitatively and quantitatively demonstrate the potential of sub-Nyquist sampling-based shear-wave elasticity imaging, indicating that our approach could be practically useful in three-dimensional shear-wave elasticity imaging, where a massive amount of ultrasound data is required.

• Structural Engineering and Mechanics
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• v.82 no.6
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• pp.701-711
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• 2022

The nonlocal elasticity as well as Mindlin's first-order shear deformation plate theory are proposed to investigate thermal vibrational of a nanoplate placing on a three-factor foundation. The Winkler-Pasternak elastic foundation is connected with the viscous damping to obtain the present three-parameter viscoelastic model. Differential equations of motion are derived and resolved for simply-supported nanoplates to get their natural frequencies. The influences of the nonlocal index, viscous damping index, and temperature changes are investigated. A comparison example is dictated to validate the precision of present results. Effects of other factors such as aspect ratio, mode numbers, and foundation parameters are discussed carefully for the vibration problem. Additional thermal vibration results of nanoplates resting on the viscoelastic foundation are presented for comparisons with future investigations.

• International Area Studies Review
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• v.21 no.4
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• pp.3-17
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• 2017

The purpose of the paper is to suggest the empirical evidences for the effects of factor prices on the export performance in the Korean manufacturing industries during the period 1975:1-2016:4. The paper is to set up the error correction model derived from the autoregressive distributed lag scheme and to estimate the factor price elasticities of export in the 8 manufacturing industries. The real wage, interest and import price index elasticities of export all were estimated to be statistically significant at 1% level in the most industries with showing negative signs as expected. And the real wage elasticity proved to likely be smaller as the industries become more capital-intensive while the import price index elasticity tended to become larger in industries with larger ratio of imported intermediate goods to output. The empirical results suggest that the declines in input factor prices since the foreign exchange crisis in the end of 1997 have positive effects on the export performance in the Korean manufacturing industries.

• Steel and Composite Structures
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• v.38 no.5
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• pp.477-496
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• 2021

The main objective of this paper is to study vibration of sandwich open cylindrical panel with damaged core and FG face sheets based on three-dimensional theory of elasticity. The structures are made of a damaged isotropic core and two external face sheets. These skins are strengthened at the nanoscale level by randomly oriented Carbon nanotubes (CNTs) and are reinforced at the microscale stage by oriented straight fibers. These reinforcing phases are included in a polymer matrix and a three-phase approach based on the Eshelby-Mori-Tanaka scheme and on the Halpin-Tsai approach, which is developed to compute the overall mechanical properties of the composite material. Three complicated equations of motion for the panel under consideration are semi-analytically solved by using 2-D differential quadrature method. Several parametric analyses are carried out to investigate the mechanical behavior of these multi-layered structures depending on the damage features, through-the-thickness distribution and boundary conditions. It is seen that for the large amount of power-law index "P", increasing this parameter does not have significant effect on the non-dimensional natural frequency parameters of the FG sandwich curved panel. Results indicate that by increasing the value of isotropic damage parameter "D" up to the unity (fully damaged core) the frequency would tend to become zero. One can dictate the fiber variation profile through the radial direction of the sandwich panel via the amount of "P", "b" and "c" parameters. It should be noticed that with increase of volume fraction of fibers, the frequency parameter of the panels does not increase necessarily, so by considering suitable amounts of power-law index "P" and the parameters "b" and "c", one can get dynamic characteristics similar or better than the isotropic limit case for laminated FG curved panels.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.355-363
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• 2023

Purpose: Sonographic elastography can be used to evaluate the hardness of muscle tissue through the application of compression. Strain elastography gauges hardness through the comparison of echo sets before and after compression. This study utilized ultrasonography to measure the thickness and hardness of the masseter muscle in individuals with temporomandibular joint(TMJ) osteoarthritis. Materials and Methods: This study included 40 patients who presented with joint pain and were diagnosed with TMJ osteoarthritis via diagnostic cone-beam computed tomography, along with 40 healthy individuals. The thickness and hardness of each individual's masseter muscle were evaluated both at rest and at maximum bite using ultrasonography. The Mann-Whitney U test and the chi-square test were employed for statistical analysis, with the significance level set at P<0.05. Results: The mean thickness of the resting masseter muscle was 0.91 cm in patients with osteoarthritis, versus 1.00 cm in healthy individuals. The mean thickness of the masseter muscle at maximum bite was 1.28 cm in osteoarthritis patients and 1.36 cm in healthy individuals. The mean masseter elasticity index ratio at maximum bite was 4.51 in patients with osteoarthritis and 3.16 in healthy controls. Significant differences were observed between patients with osteoarthritis and healthy controls in both the masseter muscle thickness and the masseter elasticity index ratio, at rest and at maximum bite (P<0.05). Conclusion: The thickness of the masseter muscle in patients with TMJ osteoarthritis was less than that in healthy controls. Additionally, the hardness of the masseter muscle was greater in patients with TMJ osteoarthritis.

• Science of Emotion and Sensibility
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• v.12 no.1
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• pp.77-86
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• 2009

A comfort evaluation of car seat clothing has been proposed for high comforts interior seat clothing. Car seat covers have received wide spread attention due to their man-machine interface working. And then, it will be necessary for measurements on delicate basic mechanical-properties, which closely relate with human touch feeling of its materials. In this research, we have utilized $KES-FB^{(R)}$(Kawabata Evaluation System) series, $^ST300{(R)}$ analogue softness tester and friction tester for measurement a physical properties. In order to consider both kansei and physical properties on interior seat covers, we firstly have established subjective words of judgement for the seat covers. Secondly, related them to the objective measurement of physical properties. Each kansei-language has clearly defined as 'Softness', 'Elasticity', 'Volume' and 'Stickiness' for the adjectives of leather car seat covers. These technical terms have correlated to physical properties in other words, h (mm), bending moment ($gf^*$cm/cm), To-Tm (mm) and ${\mu}$. At this time, fuzzy logic has utilized to predict the value of kansei language through physical values. On the basis of this result, finally it is possible to predict quality index of car seat covers using neural networks technique. In short, we develop a quality evaluation system of car seat clothing combining four physical quantities with kansei engineering.

• Smart Structures and Systems
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• v.23 no.2
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• pp.141-153
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• 2019

This research deals with wave propagation of the functionally graded (FG) nano-beams based on the nonlocal elasticity theory considering surface and flexoelectric effects. The FG nano-beam is resting in Winkler-Pasternak foundation. It is assumed that the material properties of the nano-beam changes continuously along the thickness direction according to simple power-law form. In order to include coupling of strain gradients and electrical polarizations in governing equations of motion, the nonlocal non-classical nano-beam model containg flexoelectric effect is used. Also, the effects of surface elasticity, dielectricity and piezoelectricity as well as bulk flexoelectricity are all taken into consideration. The governing equations of motion are derived using Hamilton principle based on first shear deformation beam theory (FSDBT) and also considering residual surface stresses. The analytical method is used to calculate phase velocity of wave propagation in FG nano-beam as well as cut-off frequency. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as flexoelectric coefficients of the surface, bulk and residual surface stresses, Winkler and shear coefficients of foundation, power gradient index of FG material, and geometric dimensions on the wave propagation characteristics of FG nano-beam. The numerical results indicate that considering surface effects/flexoelectric property caused phase velocity increases/decreases in low wave number range, respectively. The influences of aforementioned parameters on the occurrence cut-off frequency point are very small.

• Structural Engineering and Mechanics
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• v.61 no.6
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• pp.721-736
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• 2017

In this paper, free vibration characteristics of functionally graded (FG) nanobeams embedded on elastic medium are investigated based on third order shear deformation (Reddy) beam theory by presenting a Navier type solution for the first time. The material properties of FG nanobeam are assumed to vary gradually along the thickness and are estimated through the power-law and Mori-Tanaka models. A two parameters elastic foundation including the linear Winkler springs along with the Pasternak shear layer is in contact with beam. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived based on third order shear deformation beam theory through Hamilton's principle and they are solved applying analytical solution. According to the numerical results, it is revealed that the proposed modeling can provide accurate frequency results of the FG nanobeams as compared to some cases in the literature. The obtained results are presented for the vibration analysis of the FG nanobeams such as the influences of foundation parameters, gradient index, nonlocal parameter and slenderness ratio in detail.