• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.175-182
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• 1998

This study was to investigated physical properties of lining fabric (Nylon, Acetate, Rayon and Polyester) such as shrinkage, tensile strength, moisture regain and crease resistance. The results were as follows. 1. The number of repeated washing times and the concentration of the detergent almost didn't affect on the change of tensile strength. 2. As washing increase more, the shrinkage of all sample was more increased. In the case of Rayon, it was showed that shrinkage was high by $1{\sim}3$ times washing. In the case of Nylon, it was showed minus shrinkage according to frequency of washing. 3. The moisture regain was very decreased by 1 times washing. But the moisture regain was increased with increase in frequency of washing and resulted in it was showed a similar value with controls. 4. As the frequency of washing and the concentration of detergent increase more, the crease resistance was decreased considerably because the elasticity of fiber decreased by mechanical force such as tension, bending and pressure and alkali.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.7 no.1
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• pp.7-10
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• 2009

Purpose : The purpose of this study was to investigate the effect of electrical stimulation applied in dominant forearm on autonomic nervous system response of both hands. Methods : Fourteen healthy subjects (women) received low frequency-high intensity electrical stimulation to one forearm. The subjects assigned to two groups; a ipsilateral stimulation group (n=7) and a contralateral stimulation group (n=7). The electrode attachment was arranged on the forearm of the dominant arm and the electricity stimulus time was set as 15 minutes. Measuring items were the skin conduction velocity, the blood flow, and the pulse rate, which were measured total 3 times (pre, post, and post 10 min.). Results : The skin conduction velocity showed a significant difference according to the change of the time in both hands, but there was no significant difference according to time in the blood flow, and the change of the pulse frequency regardless of stimulus side. Conclusion : These results demonstrate that the low frequency-high intensity electrical stimulation applied dominant forearm can increase selectively only with the skin conduction velocity, which may be helpful for the activation of the sudomotor function of both hands by the activation of sympathetic nerve.

• Journal of Korean Society for Quality Management
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• v.47 no.4
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• pp.895-910
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• 2019

Purpose: The purpose of this study is to lighten the APU (Auxiliary Power Unit) structure of the KAAV (Korea Assault Amphibious Vehicle) through structural analysis. Methods: Commercially-available program (MIDAS.NFX) was used for finite element analysis. Frequency response analysis was performed through linear static and mode analyses to verify the structural stability according to the change of the structural materials. Results: Numerical simulation (linear static, mode and frequency response analyses) results showed that the safety factor of the APU was over 1.5 even under the worst case conditions. The APU made by aluminum structures was expected to be available in the military field, since every requirements in the KDS (Korean Defense Specifications) was fulfilled during the various tests and evaluations. Conclusion: The structural analysis was verified that the structural stability of the APU structure of the KAAV after change of the structural material.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.341-345
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• 2005

Structural Dynamics Modification (SDM) is a very effective technique to improve structure's dynamic characteristics by adding or removing auxiliary structures, changing material properties and shape of structure. Among those of SDM technique, the method to change shape of structure has been mostly relied on engineer's experience and trial-and-error process which are very time consuming. In order to develop a systematic method to change structure shape, surface grooving technique is studied. In this work, the shape of base structure was modified to improve its dynamic characteristics such as natural frequencies via surface grooving technique. Grooving shape was formed by mergingthe neighboring small embossing elements after analyzing frequency increment sensitivities of all the neighboring emboss elements. For this process, Criterion Factor was introduced and the initial grooving was started from the element having highest strain energy and the grooving is expanded into neighboring element. The range of targeting grooving area to check its frequency variations restricted to their neighboring area to reduce the computation effort. This surface grooving technique was successfully applied to a hard disk drives (HDD) cover model to raise its natural frequency by giving some groove on its surface.

• Elastomers and Composites
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• v.43 no.3
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• pp.166-172
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• 2008

The resistance and frequency change of a quartz crystal microbalance during toluene absorption was measured for poly(vinyl acetate) (PVAc) with 268 nm thickness. Solubility of toluene in PVAc were measured at temperatures from 25$^{\circ}C$ to 42$^{\circ}C$ and pressures up to 28.4 torr. The frequency of a quartz crystal microbalance increased with increasing temperature and decreased with an increase in toluene vapor pressure. The resistance of a quartz crystal microbalance increased with increasing toluene vapor pressure and decreased with an increase in temperature. A greater pressure of toluene results in a greater solubility of the toluene into the PVAc film. The change of solubility was calculated by Sauerbrey equation.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1174-1180
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• 2015

We investigate in this paper the radiated electromagnetic waves together with the discharge characteristics of Trichel pulse of negative DC corona discharge in air in pin-to-plate and wire-to-plate configurations. The feature of the current pulse and the frequency spectrum of the electromagnetic radiations were measured under various pressures and gas gaps. The results show that the repetition frequency and the amplitude of Trichel pulse current depend on the discharge conditions, but the rising time of the pulse relates only to the radius of needle or wire and keeps constant even if the other conditions (including the discharge current, the gas gap and the gas pressure) change. There exists the characterized spectrum of electromagnetic waves from negative corona discharge in Trichel pulse regime. These characterized radiations do not change their frequency at a given cathode geometry even if the averaged current, the gas gap or the air pressure changes, but the amplitude of radiations changes accordingly. The characterized electromagnetic radiations from Trichel pulse corona relate to the formation or the rising edge of current pulse. It confirms that the characterized radiations from Trichel pulse supply information of discharge system and provide a potential method for detecting charged targets.

• Journal of Korean Academy of Nursing
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• v.37 no.7
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• pp.1149-1158
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• 2007

Purpose: The purpose of this study was to identify the risk factors for a nosocomial urinary tract infection in intensive care units with a foley catheterization which showed a positive urine culture. Method: Three-hundred eighty-seven patients were included in the study. A retrospective review of the electrical medical record system's databases and medical record sheets in hospitalized patients from January 2003 to December 2003 was used. The collected data was analyzed by descriptive statistics, t-test, chi-square test and logistic regression analysis. Result: The frequency of the participants' nosocomial urinary tract infection was 72.9%. Significant risk factors for a nosocomial urinary tract infection were 'age', 'place of catheter insertion', 'frequency of catheter change', and 'duration of catheterization'. These variables explained 18.4% of variance in the experience of nosocomial urinary tract infection in intensive care units with foley catheterization. Conclusion: Medical personnel can decrease the incidence of a nosocomial urinary tract infection by recognizing and paying attention to the duration of catheterization, frequency of catheter change, and place of catheter insertion. As a result, specific and scrupulous strategies should be developed to reflect these factors for decreasing nosocomial urinary tract infections.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.854-859
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• 2001

An eigenvalue analysis of a tunable micro-mechanical actuator is presented. The actuator is modeled as a continuum structure. The eigenvalue modified by the tuning voltage is computed through the linearization of the relation between the electrostatic force and the displacement at the equilibrium. A staggered algorithm is employed to perform the coupled analysis of the electrostatic and elastic fields. The stiffness matrix of the actuator is modified at this equilibrium state. The displacement field is perturbed using an eigenmode profile of the actuator. The configuration change of the actuator due to perturbation modifies the electrostatic field and thus the electrostatic force. The equivalent stiffness matrix corresponding to the perturbation and the change in the electrostatic force is then added to stiffness matrix in order to explain natural frequency shifting. The numerical examples are presented and compared with the experiments in the literatures.

• Journal of The Korean Association For Science Education
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• v.32 no.6
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• pp.1050-1062
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• 2012

Concepts of science have been developed by occupying 'ecological niche' within conceptual ecology. The ecological niche is determined from the mutual effect between intellectual environmental of the learner and new concept, which few studies have been conducted. This study examined how the ecological niche of the concept of photosynthesis in $7^{th}$ grade is changed by instruction. The ecological niche was analyzed using 2 methods: (1) the change in the diversity of concepts, and (2) the change in the proximity of concepts based on the frequency and the relativeness score of the concepts. The concept of photosynthesis was analyzed in the 4 domains in the place of photosynthesis, products of photosynthesis, reactants of photosynthesis, and environmental factors. The results of this study are as follows: (1) reduced diversity of concepts, (2) increased frequency and relativeness score of the scientific concepts, and (3) increased proximity of the scientific concepts by instruction. With these results, the mutual effects of the concepts within the conceptual ecology have become active by class to differentiate the relationships between the concepts, which accordingly displayed their changes in status.

• Phonetics and Speech Sciences
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• v.10 no.2
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• pp.69-76
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• 2018

The elderly are at increased risk of developing dysphagia due to aging and illnesses. The aim of the current study was to analyze, via an acoustic study, the change in the voice quality of normal elderly people after a 3oz water-swallow test. Subjects included a group of 60 normal elderly people (age: $mean{\pm}SD=76.9{\pm}6.66$) and 60 healthy young adults (age: $mean{\pm}SD=25.1{\pm}2.36$). Every participant produced a five-second /a/ phonation pre- and post-swallowing, and the fractioned two-second sections were analyzed using the MDVP (multi dimensional voice program) analysis. The elderly group demonstrated a post-swallowing increase in the following related acoustic parameters: fundamental frequency, fundamental frequency variation, amplitude-variation, and noise in both two-second sections. However, the younger group showed an increase only in frequency related acoustic parameters (i.e., STD ) in the first two-second section. The significant changes in values in the post-swallowing parameters might indicate temporary irregularities in pitch and amplitude along with higher amounts of noise in the voice. The results could be attributed to water residues in the vocal fold and vocal tract, as well as a deterioration of the motor and sensory functions caused by anatomical and physiological changes that result from aging.