• International Journal of Advanced Culture Technology
• /
• v.4 no.3
• /
• pp.24-38
• /
• 2016

The purpose of our study is to analyze the effect of socio-economic status on the diet pattern of Korean adults. Raw data from the fifth (2010-2012) Korea National Health and Nutrition Examination Survey (KNHANES) were used, and finally 11,700 adults were analyzed as subjects. Results in consideration of the socio-economic status of the subjects, a linear trend was observed in men in which the odds ratio of having lunch (p for trend=0.006) and dinner (p for trend=0.0317) decreased as the level of education went down. In diet frequency, a decreasing trend (p for trend=0.0328) was observed in which the odds ratio of having 3 meals a day reduced as the household income lowered. For women, a linear trend (p for trend=0.0012) was observed in which the frequency of dinner decreased as the level of education became lower. A falling trend in the rate of having 3 meals a day was also observed (p for trend=0.0135). Our study analyzed the characteristics of the diet patterns of individuals according to their socio-economic status with the purpose of suggesting guidelines for correcting. To prevent this, we will need education and awareness and public attention for the practice of correct eating habits.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.5 no.3
• /
• pp.182-190
• /
• 1993

A numerical technique is presented to calculate the motions of 6 d.o.f and mooring tensions for a catenary moored floating breakwater. The breakwater may be subjected to the 3-D combination of regular or irregular waves and stationary forces. The added mass coefficients at the infinitive frequency of input wave and the variations of damping and exciting force coefficients are calculated using the source distribution method. The coefficients are used to constitute motion equations in time domain which are solved by WiIson-$\theta$ method. The solutions agree quite well with either static displacement determined from Newton method under the stationary force only or 6 d.o.f determined from the frequency domain analysis under regular wave only. An example analysis is also done for a floating breakwater to demonstrate its applicability.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1998.04a
• /
• pp.327-334
• /
• 1998

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and toll.or structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the special orthotropic plates with free edges supported on elastic foundation and with a pair of opposite edges under axial forces is presented. Such plates represent the concrete highway slab and hybrid composite pavement of bridges. The reinforced concrete slab can be assumed as a special orthotropic plate, as a close approximation. The highway slab is supported on elastic foundation, with free boundaries. Sometimes, the pair of edges perpendicular to the traffic direction may be subject to the axial forces. The plate is subject to the concentrated load/loads, in the form of traffic loads, or the test equipments. Any method nay be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper. The influence of the modulus of the foundation, the aspect ratio of the plate, and the magnitudes of the axial forces and the concentrated attached mass on the plate, on the natural frequency is thoroughly studied.

• Journal of Astronomy and Space Sciences
• /
• v.34 no.4
• /
• pp.251-256
• /
• 2017

The electric coupling between the lithosphere and the ionosphere is examined. The electric field is considered as a timevarying irregular vertical Coulomb field presumably produced on the Earth's surface before an earthquake within its epicentral zone by some micro-processes in the lithosphere. It is shown that the Fourier component of this electric field with a frequency of 500 Hz and a horizontal scale-size of 100 km produces in the nighttime ionosphere of high and middle latitudes a transverse electric field with a magnitude of ~20 mV/m if the peak value of the amplitude of this Fourier component is just 30 V/m. The time-varying vertical Coulomb field with a frequency of 500 Hz penetrates from the ground into the ionosphere by a factor of ${\sim}7{\times}10^5$ more efficient than a time independent vertical electrostatic field of the same scale size. The transverse electric field with amplitude of 20 mV/m will cause perturbations in the nighttime F region electron density through heating the F region plasma resulting in a reduction of the downward plasma flux from the protonosphere and an excitation of acoustic gravity waves.

• Aerospace Engineering and Technology
• /
• v.5 no.2
• /
• pp.102-107
• /
• 2006

In this study, the dynamic environment of satellite consists of excessive vibration at low frequency and irregular acceleration transferred by launch vehicle structure. Excessive vibration at low frequency is generally approximated by a sinusoidal wave from 100Hz to 200Hz and primarily used to preliminary design The random vibration is created by structural vibration due to the combustion of launch vehicle, separation stage and external aerodynamic noise. these are transferred to the adapter structure between satellite and launch vehicle through the structure of launch vehicle. random vibration is being specified for acceptance tests, screening tests, and qualification tests, because it has been shown that random vibration more closely represents the true environments in which the electronic equipment must operate.

• Computational Structural Engineering
• /
• v.10 no.1
• /
• pp.149-158
• /
• 1997

This paper presents the illustration of application under attached point mass to the special orthotropic plates with a pair of opposite edges simply supported and the other pair of opposite edges free. Design engineers need to calculate the natural frequencies of such elements but obtaining exact solution to such problems is very much difficult. Pretlove reported a method of analysis of beams with attached masses using the concept of effective mass. This method, however, is useful only for certain simple types of beam. Therefore, considering the method has been developed by D. H. Kim(1974) is simple, accurate, and very effective for the plates with arbitrary boundary conditions and irregular sections, this paper calculates the natural frequencies of composite laminated plate under attached point mass/masses.

• Journal of the East Asian Society of Dietary Life
• /
• v.9 no.2
• /
• pp.135-148
• /
• 1999

This is a descriptive study of consumption Patterns of how to take meals in everyday life. The data used was collected from a probability sample by multi-stage cluster sampling, drawn from those who were living in the Ulsan Metropolitan Area. Face-to-face interviews were conducted by trained interviewers with a household member who was between the ages of 15 and 60 in 1989 and had the earliest birthday, resulting in a sample of 1,232 respondents. Univariate and bivariate analyses were made to describe behavioral patterns of taking meals. Meal-taking behaviors under this study include frequency of taking meals per day, regularity of taking meals, which meal to skip, number of frequency of taking a meal by oneself. reasons of skipping and irregular meals, and eatting out. Half of the respondents reported to take meals three times a day, while those who skipped at least a meal reported as one most frequently skipped. Of reasons not to take a meal on a regular basis, "too busy to eat" was most frequently mentioned. Only 32.8% of the respondents reported dining-out once a week.ce a week.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.4
• /
• pp.77-84
• /
• 2011

Tire manufactures have dealt with noise problem by varying the pitch of the tread. The various formulas for the variations are generally determined differently, however. Often these variations are based on a combination of trial and error, intuition, and economics. Some manufactures have models and analogs to test tread patterns and their variations. These efforts, however practical, do not determine the best variation beforehand or guarantee the best results. For this reason it was felt that a general mathematical approach for determining the best variation was needed. Moreover, the method should be completely general, easy to use, and sufficiently accurate. This paper discusses a mathematical method called Mechanical Frequency Modulation(MFM) which meets the above requirements. Thus, MFM pertains to computing an irregular time sequence of events so that the resulting excitation spectrum is shaped to a preferred form. The first part of this paper treats the theoretical basis for computing an optimum variation ; the second part discusses experimental results and simulation program which corroborate the theory.

• Advances in nano research
• /
• v.12 no.5
• /
• pp.483-488
• /
• 2022

The present work is an attempt to study the vibration analysis of the single-walled carbon nanotubes (SWCNTs) under the effect of the surface irregularity using Donnell's model. The surface irregularity represented by the parabolic form. According to Donnell's model and three-dimensional elasticity theory, a novel governing equations and its solution are derived and matched with the case of no irregularity effects. To understand the reaction of the nanotube to the irregularity effects in terms of natural frequency, the numerical calculations are done. The results obtained could provide a better representation of the vibration behavior of an irregular single-walled carbon nanotube, where the aspect ratio (L/d) and surface irregularity all have a significant impact on the natural frequency of vibrating SWCNTs. Furthermore, the findings of surface irregularity effects on vibration SWCNT can be utilized to forecast and prevent the phenomena of resonance of single-walled carbon nanotubes.

• Journal of information and communication convergence engineering
• /
• v.22 no.1
• /
• pp.14-22
• /
• 2024

This study presents the design of a Wilkinson power divider for three-way output ports (WPD3OP), which incorporates a defected ground structure (DGS). An asymmetric power divider is integrated into the output ports of the conventional Wilkinson power divider (WPD), establishing a three-way output port configuration. The DGS introduces periodic or irregular patterns into the ground plane to suppress unwanted electromagnetic wave propagation, and its incorporation can enhance the performance of the power divider, in terms of the power-division ratio, isolation, and bandwidth, by reducing spurious resonances. The proposed design algorithm for an asymmetric power divider for three-way output ports is analyzed via circuit simulations using High-Frequency Simulation Software (HFSS). The results verify the validity of the proposed method. The analysis of the WPD3OP integrated with DGS certifies the achievement of a center frequency of 2 GHz. This confirmation is supported by schematic ideal design simulation results and measurements encompassing insertion losses, return losses, and isolation.