• Journal of the Korean Mathematical Society
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• v.51 no.1
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• pp.55-65
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• 2014

A graph G is called a fractional (g, f, n)-critical graph if any n vertices are removed from G, then the resulting graph admits a fractional (g, f)-factor. In this paper, we determine the new toughness condition for fractional (g, f, n)-critical graphs. It is proved that G is fractional (g, f, n)-critical if $t(G){\geq}\frac{b^2-1+bn}{a}$. This bound is sharp in some sense. Furthermore, the best toughness condition for fractional (a, b, n)-critical graphs is given.

• Smart Structures and Systems
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• v.29 no.2
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• pp.279-286
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• 2022

In this article, a novel propagation formulation of Rayleigh waves in a compressible isotropic half-space with impedance boundary condition is proposed by embedding the normal stress. In a two-dimensional case, it is assumed that a design boundary is free of normal traction and a shear traction depends on linearly a normal component of displacements multiplied by frequencies. Therefore, impedance boundary conditions affect the normal stress, where the impedance parameters correspond to dimensions of stresses over velocity. On the other hand, vanished impedance values are traction-free boundary conditions. The main purpose of this article is to present theoretically the existence and uniqueness of a Rayleigh wave formulation relying on secular equation's mathematical analyses. Its velocity varies along with the impedance parameters. Moreover, numerical experiments with different values for the velocity of Rayleigh waves are carried out. The present Rayleigh waves study is a fundamental step in analyzing the cause and effect of physical states such as building or structure damages resulting from natural dynamics. The results of the study generate a basic design formulation theory to test the effects of Rayleigh waves affecting structures when an earthquake occurs. The presence and uniqueness of the proposed formulation is verified by mutual comparisons of several numerical examples.

• Journal of Korean Physical Therapy Science
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• v.16 no.4
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• pp.49-57
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• 2009

Background: The purpose of this study was to assess the test-retest reliability of balance measurements in older adults using balance measurement system(Good Balance). Methods: The subjects consisted of 49 female and 20 male in community-dwelling older adults. This study used a repeated-measure design. Each subject completed all the different tests once and they were then repeated with 2 minutes in between. Repeated two-ways analysis of variance(ANOVA), representing two test times and both sexes, was calculated for each of the two dependent variables. Intraclass correlation coefficients(ICCs) were used to assess the test-retest reliability. Results: 1) There was not significant difference between test and retest for mediolateral sway speed and anterioposterior sway speed under conditions of normal standing with eyes open, normal standing with eyes closed and semitandem standing with eyes open. There was not significant difference between males and females for mediolateral sway speed and anterioposterior sway speed under conditions of normal standing with eyes open, normal standing with eyes closed and semitandem standing with eyes open. There were not the interaction effects between genders and test time under three conditions. 2) The reproducibility between test and retest was excellent for anterioposterior sway speed(ICC=.77) under condition of normal standing with eyes open, and for mediolateral sway speed(ICC=.76) and anterioposterior sway speed(ICC=.84) under condition of semitandem standing with eyes open. The reproducibility between test and retest was fair to good for mediolateral sway speed(ICC=.64) under condition of normal standing with eyes open, for mediolateral sway speed(ICC=.63) and anterioposterior sway speed(ICC=.75) under condition of normal standing with eyes closed. Conclusion: Balance tests in older adults using balance measurement system(Good Balance) demonstrated acceptable levels of reliability.

• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.141-148
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• 2011

There are many factors that affect speech intelligibility and speech acceptability. Structural anomalies and neuromotor pathologies are known for the reasons of abnormal speech sounds. And there are minor variations related to oral mechanism. Speaking with restricted mouth opening related to therapeutic procedure or habitual speech pattern might affect the quality of speech sounds. So this study compared speech intelligibility and speech acceptability of recorded 24 words in two conditions (restricted mouth opening condition and normal mouth opening condition) by 30 normal hearing adults. The results showed that speech intelligibility and speech acceptability were significantly lower in restricted mouth opening condition. And speech acceptability was significantly lower than speech intelligibility in restricted mouth opening condition. Speech acceptability in restricted mouth opening condition was significantly lower especially in open vowel. These findings indicated that the mouth opening condition could affect vowel shape and could be an adverse effect on speech intelligibility and speech acceptability.

• Journal of the Korean Statistical Society
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• v.31 no.3
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• pp.379-389
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• 2002

For two normal distribution with unknown means and unknown variances, a sequential procedure for estimating the difference of two normal means which satisfies both the coverage probability condition and the $\beta$-protection is proposed under some smoothness of variable imprecision function, and the asymptotic normality of the proposed stopping time after some centering and scaling is given.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.261-266
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• 2009

We analyze the performances of the DCF, which is the medium access control protocol of IEEE 802.11 WLAN, assuming normal traffic condition. There have been much less research efforts under the normal condition than those under the saturated one. This paper proposes an analytical method of approximating the transmission attempt rate under normal condition as proportional to that under saturated condition. In result, we show that we can obtain the transmission attempt rate and the packet collision probability which quickly converge using iterative computations of relatively simple equations, and using these results we derive the network throughput and medium access delay. Numerical results show that our method is much less complex than those based on the Markov Chain while it can predict the performances quite accurately.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.43-48
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• 2012

Generally accelerated life test is well known as one method to reduce reliability qualification test period. This test is conducted under the higher stress condition than normal condition. So it can save the test time by calculating the acceleration factor from the relationship between the worst stress condition and normal condition. This paper investigates the worst stress condition for the accelerated life test to increase the acceleration factor. Especially, we focused on the method to obtain effective acceleration factors under the worst stress condition. Moreover, we considered how to decide the worst stress condition by looking for the operating limit of this system. The acceleration factor can be estimated from the ratio of the kinematic viscosity in the normal condition and the worst stress condition, the lowest temperature, by using Arrhenius relationship. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.3
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• pp.201-207
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• 2000

In this study, methodologies for checking the interference between in-core instrumentation (ICI) guide tubes for routing of ICI guide tubes in the reactor coolant system of typical Pressurized Water Reactor under cold and normal operation (NOP) conditions are presented. The closest points of ICI guide tubes under cold condition are calculated by using minimize technique and are used as data for NOP analysis. Movements of ICI guide tubes under NOP condition are performed by the commercial computer code, SUPERPIPE.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.427-432
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• 2005

This study have been compared and analyzed voice parameter under the condition of normal voice and auditory condition(noise and music) for 29 patients of orofacial pain and 31 normal people to investigate voice feature and vocal variation for auditory condition of orofacial pain patient. 1. Compared to normal voice, orofacial pain patient showed lower and unstable voice feature which has low F0 rate and high jitter and shimmer rate. 2. Voice of orofacial pain patient showed more relaxed and stable voice feature with low F0 and shimmer rate in the music condition than noise condition. 3. Normal people's voice has no significant difference between music and noise condition even though it has high F0 rate under the noise condition. As a result, orofacial pain patient showed difference of feature and different response for external auditory condition compared to normal voice. Providing of positive emotional environment such as music could be considered for better outcome of oral facial pain patient's functional disability.

• Journal of Chest Surgery
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• v.26 no.9
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• pp.701-704
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• 1993

Four to seven percent of infants born with aortic atresia have a normal-sized left ventricle in association with a ventricular septal defect and a normal mitral valve. In contrast to the more common group of infants with aortic atresia whose left ventricle is hypoplastic, this important subgroup has potential for complete operative correction involving both the right and left ventricle. Our approach was to perform complete repair at one stage. The patient who underwent single-stage repair was discharged from the hospital in good condition. Achieving a physiologically normal circulation simplifies the postoperative management of this condition.