• 대한물리치료과학회지
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• 제2권4호
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• pp.739-747
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• 1995

The purpose of this study was to evaluate and compare the Limits of stability(LOS) in hemiplegic patients who can walking independently. The LOS was measured at stable surface, unstable surface with eye open and eye closed. In this study, 18 out-patients were evaluated who were treated at Yonsei University Medical Center Rehabilitation Hospital. In order to determine the statistical significance of results, T-test, paired t-test, and Kruskal-Wallis 1-way ANOVA were applied at 0.05 level of significance. The results were as follows: 1. The mean of lateral limits of stability was 9.89 degree. 2. The mean of anteroposterior limits of stability was 6.43 degree. 3. There was a significant difference of limits of stability between sound side and affected side(p<0.05). 4. The limits of stability was significantly decreased with eye closed(p<0.05) 5. The limits of stability was significantly decreased at unstable surface(p<0.05). 6. The limits of stability was a significant difference as spasticity degree of ankle plantar flexors(p<0.05). These results showed that the limits of stability in hemiplegic patients was more decreased than that of normal adult. In order to improve the balance in hemiplegic patients, we need to increase the limits of stability.

• 대한물리치료과학회지
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• 제3권2호
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• pp.963-973
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• 1996

The purpose of this study was to evaluate and compare the limits of stability(LOS) at different sensory conditions in normal 20 years of age. The LOS was measured at stable surface, and unstable surface and the subjects stood with the feet contacted and 4 inches between the feet with the eyes open and the eyes closed. In this study, 20 physical therapy major subjects were evaluated at Wonkwang Public Health Junior College. In this study applied the paired t-test, and Kruskal-Wallis 1-way ANOVA to determine the statistical significance of results at 0.01 level of significance. The results were as follows: 1. The mean of lateral limits of stability was b.67 degree at stable surface with the eyes open and standing with the feet contacted. 2. The mean of anteroposterior limits of stability was 9.78 degree at stable surface with the eyes open and standing with the feet contacted. 3. The mean of lateral limits of stability was 15.10 degree at stable surface with the eyes open and standing with 4 inches between the feet. 4. The mean of anteroposterior limits of stability was 11.72 degree at stable surface with the eyes open and standing with 4 inches between the feet. 5. The anterior-posterior and lateral limits of stability significantly decreased with the eyes closed(p<0.01). 6. The anterior-posterior and lateral limits of stability significantly decreased at unstable surface(p<0.01). 7. There was no significant difference of limits of stability as the height and foot length(p>0.01).

• 대한기계학회논문집
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• 제11권1호
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• pp.145-153
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• 1987

본 논문에서는 예혼합동축분류화염에 있어서 재순환역 안으로의 기체(공기, 연료, 혼합기) 주입과 2차공기의 족회가 화염안정성, 화염형상 및 재순환역에 미치는 영향을 명확히 하였다.

• 대한수학회논문집
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• 제24권1호
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• pp.5-16
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• 2009

In this paper, we obtain the general solution and the generalized Hyers-Ulam-Rassias stability for a following functional equation $$\sum\limits_{i=1}^mf(x_i+\frac{1}{m}\sum\limits_{{i=1\atop j{\neq}i}\.}^mx_j)+f(\frac{1}{m}\sum\limits_{i=1}^mx_i)=2f(\sum\limits_{i=1}^mx_i)$$ for a fixed positive integer m with $m\;{\geq}\;2$. This is applied to investigate derivations and their stability on proper Lie $CQ^*$-algebras. The concept of Hyers-Ulam-Rassias stability originated from the Th. M. Rassias stability theorem that appeared in his paper: On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72(1978), 297-300.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제29권2호
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• pp.179-188
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• 2022

In this paper we investigate the Hyers-Ulam stability of the s-variable additive and l-variable quadratic functional equations of the form $$f\(\sum\limits_{i=1}^{s}x_i\)+\sum\limits_{j=1}^{s}f\(-sx_j+\sum\limits_{i=1,i{\neq}j}^{s}x_i\)=0$$ and $$f\(\sum\limits_{i=1}^{l}x_i\)+\sum\limits_{j=1}^{l}f\(-lx_j+\sum\limits_{i=1,i{\neq}j}^{l}x_i\)=(l+1)$$$\sum\limits_{i=1,i{\neq}j}^{l}f(x_i-x_j)+(l+1)\sum\limits_{i=1}^{l}f(x_i)$ (s, l ∈ N, s, l ≥ 3) in quasi-Banach spaces.

• 한국수소및신에너지학회논문집
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• 제17권2호
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• pp.158-165
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• 2006

In order to provide the database for designing microcombustors, the combustion characteristics of premixed methane and propane air microflames at normal and elevated temperatures and atmospheric pressure generated on a microtube were studied experimentally and computationally. The stability limits of premixed microflames and the propensity of the microflames near the stability limits were experimentally determined, while the structure of the microflame at the fuel-leanest limit was obtained using a two-dimensional CFD simulation with a reduced kinetic mechanism. For all the microflames, the stability limits were observed only in the fuel-rich region. Results also show substantial extension of stability limits with elevated temperature that is realistic condition for micro fuel processing and significant fuel dilution immediately near the tube exit due to a low Peclet number times Lewis number effect.

• 한국항공우주학회지
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• 제32권10호
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• pp.93-101
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• 2004

액체 로켓엔진에서 발생하는 고주파 연소 불안정성을 예측하기 위해 선형 안정한계를 계산하는 방법을 연구하였다. 기존의 선형이론에 근거하여 유도된 선형 안정한계를 나타내는 안정한계 식을 채택하였으며, 그 식을 구성하는 각각의 항을 정량적으로 평가하는 방안들이 제시되었다. 안정한계 계산에 필요한 열-화학 물성치와 유동 변수를 열역학적 평형계산과 CFD 해석 및 실험 결과로부터 평가하는 구체적 절차들을 상세히 제시하였다. 실제 로켓엔진으로서 시험 데이터가 확보되어 있는 KSR-III 로켓엔진에 대해서 제시한 방법을 적용하여 안정한계 곡선을 구하였다. 계산결과는, 해당 엔진에 대해 정량적으로 타당한 안정한계 곡선을 보여주었다. 이를 토대로 해당 엔진의 안정성 특성을 분석하였다. 본 연구에서 제시된 선형 안정한계 계산 방법은 진정한 예측의 1차적 근사로서 활용할 만한 가치가 있으며, 엔진 개발 초기에 근사적으로 안정성 경향을 분석하기에 유용할 것이다.

• 대한수학회보
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• 제45권3호
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• pp.587-600
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• 2008

In this paper we establish the general solution and investigate the Hyers-Ulam-Rassias stability of the following functional equation in quasi-Banach spaces. $${\sum\limits_{{{1{\leq}i<j{\leq}4}\limits_{1{\leq}k<l{\leq}4}}\limits_{k,l{\in}I_{ij}}}\;f(x_i+x_j-x_k-x_l)=2\;\sum\limits_{1{\leq}i<j{\leq}4}}\;f(x_i-x_j)$$ where $I_{ij}$={1, 2, 3, 4}\backslash${i, j} for all $1{\leq}i<j{\leq}4$. The concept of Hyers-Ulam-Rassias stability originated from Th. M. Rassias' stability theorem that appeared in his paper: On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc.

• 충청수학회지
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• 제33권3호
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• pp.319-326
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• 2020

In this paper, we establish a general solution of the following functional equation $$mf\({\sum\limits_{k=1}^{n}}x_k\)+{\sum\limits_{t=1}^{m}}f\({\sum\limits_{k=1}^{n-i_t}}x_k-{\sum\limits_{k=n-i_t+1}^{n}}x_k\)=2{\sum\limits_{t=1}^{m}}\(f\({\sum\limits_{k=1}^{n-i_t}}x_k\)+f\({\sum\limits_{k=n-i_t+1}^{n}}x_k\)\)$$ where m, n, t, i_t ∈ ℕ such that 1 ≤ t ≤ m < n. Also, we study Hyers-Ulam-Rassias stability for the generalized quadratic functional equation with n-variables and m-combinations form in quasi-𝛽-normed spaces and then we investigate its application.

• 대한임상전기생리학회지
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• 제10권1호
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• pp.1-5
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• 2012

Purpose : In this study, stroke patients' limits of stability and functional reach test and tibialis anterior, gastrocnemius muscle of lower extremity muscle activities to evaluate the correlation. Methods : 30 adult stroke patients to participate in this study. Limits of stability were measured using biorescue, tibialis anterior and gastrocnemius muscle of muscles activities were measured with functional reach test when there was movement. Results : Limits of stability and functional reach test (r=0.753, p<0.01), RMS value of the limits of stability and tibialis anterior muscle (r=0.706, p<0.01), RMS value of the limits of stability and gastrocnemius muscle (r=0.766, p<0.01), RMS value of the functional reach test and tibialis anterior muscle (r=0.835, p<0.01), RMS value of the functional reach test and gastrocnemius muscle (r=0.663, p<0.01), RMS value of the tibialis anterior and gastrocnemius muscle (r=0.816, p<0.01) correlations are shown as statistically significant. Conclusion : The balance and lower extremity muscle activities of stroke patients were studied, and were positively correlated with the RMS value of the limits of stability and functional reach test, tibialis anterior muscle, and gastrocnemius muscle. This study has shown that stroke patients' ankle joint muscle activity can greatly.