• Industrial Engineering and Management Systems
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• 제12권1호
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• pp.2-8
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• 2013

Uncertainty theory is a branch of mathematics based on normolity, duality, subadditivity and product axioms. Uncertain process is a sequence of uncertain variables indexed by time. Canonical Liu process is an uncertain process with stationary and independent increments. And the increments follow normal uncertainty distributions. Uncertain differential equation is a type of differential equation driven by the canonical Liu process. Stability analysis on uncertain differential equation is to investigate the qualitative properties, which is significant both in theory and application for uncertain differential equations. This paper aims to study stability properties of linear uncertain differential equations. First, the stability concepts are introduced. And then, several sufficient and necessary conditions of stability for linear uncertain differential equations are proposed. Besides, some examples are discussed.

• 한국의류산업학회지
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• 제11권6호
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• pp.896-903
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• 2009

The purpose of this study was to compare and analyze the present condition of pants grading and the methods for the specific dimensional increments, a questionnaire has been conducted. For the questionnaire, 16 casual wear brands, which were on higher ranking of sales in Korea, were selected. The results are summarized as follows. Based on the pants grading data resulting from the research conducted on the (16) domestic clothing brands, the grading method could be classified into three different types. According to the criteria; i.e., the front and back divided by crease of pants and the deviation ratio of the grading increments of the waist and the hip girth, the grading types were (1) G1: front 5:5, back 5:5, (2) G2: front 4:6, back 4:6, and (3) G3: front 4:6, back 3:7.

• Tribology and Lubricants
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• 제14권4호
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• pp.7-14
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• 1998

A correlation between the low-cycle fatigue life and the scuffing-failure life is demonstrated using the plastic strain increment in boundary lubricated sliding. Loadings proportional to hardness with three different lubricated conditions were used to evaluate the plastic strain increments. As the results of scuffing tests using vacuum pump oils in nitrogen gas, plastic strain increment shows 0.0062, and in the mineral oils and commercial engine oils in air, plastic strain increments show 0.0042 and 0.00092. Those are very useful to describe quantitatively the real lubricated sliding conditions, and are very effective to find the relation between the low-cycle fatigue life and the scuffing-failure life.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.333-336
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• 2002

Traditional methods of earth reinforcement consist of introducing strips, fabrics, or grids into an earth mass. Recently, discrete fibers are simply added and mixed with the soil, much the same as cement, lime or other additives. The advantages of randomly distributed fibers is the maintenance of strength isotropy, low decrease in post-peak shear strength and high stability at failure. In this study, new composite reinforcement structures which consist of geotextile and randomly distributed discrete fibers were examined their engineering properties, such as shear strength of the composite reinforced soil. The increments of shear strength of composite reinforced soils were the sum of increments by fiber and woven geotextile respectively.

• 한국농공학회지
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• 제45권6호
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• pp.162-171
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• 2003

Traditional methods of earth reinforcement consist of introducing strips, fabrics, or grids into an earth mass. Recently, discrete fibers are simply added and mixed with the soil, much the same as cement, lime or other additives. The advantages of randomly distributed fibers is the maintenance of strength isotropy, low decrease in post-peak shear strength and high stability at failure. In this study, new composite reinforcement structures which consist of geotextile and randomly distributed discrete fibers were examined their engineering properties, such as shear strength of the composite reinforced soil and permeability of short fiber reinforced soil. The increments of shear strength of composite reinforced soils were the sum of increments by fiber and woven geotextile, respectively. The permeability of short fiber reinforced soil was increased with fiber mixing ratio.

• 한국광학회지
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• 제8권2호
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• pp.88-94
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• 1997

감쇠최소자승법을 최적회 기법으로 사용하여 사진 렌즈계와 픽업 광학계용 비구면 대물렌즈를 설계하였다. 최적화 초기에 임의로 감쇠계수를 선택한 다음 최적화 과정의 수렴 속도와 안정성을 높이기 위하여 미분증가치의 최적성 평가법을 도입하였다. 최적성 평가법을 만족하는 미분증가치를 사용한 경우 최적화의 수렴성과 안정성이 증진되었으며, 최적화에 의해 설계된 렌즈계들의 성능은 설계 목표치를 잘 만족하였다.

• 한국기계연구소 소보
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• 통권18호
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• pp.55-66
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• 1988

Many direct integration methods are used for numerical analyses of dynamic motion. In these methods, the governing equations of a dynamic system are integrated successively using a step-by-step numerical integration procedure. Time derivatives in the equations are generally approximated using difference formulas involving one or more increments of the time. Time increment has closely relationship with the accuracy of the motion analysis. In this paper, a 4th order Houbolt direct integration method is derived. For a spring-mass system, the motion of the system are analyzed from the 3rd order Houbolt and the 4th order Houbolt approaches respectively. Finally the paper proposes the optimal time-increment based on the accuracy of numerical analyses.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2016년도 춘계 종합학술대회 논문집
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• pp.267-268
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• 2016

This study aimed to examine the therapeutic effects of backward walking. The subjects were randomly assigned to an experimental group of 16 subjects and a control group of 17 subjects. All subjects walked barefoot for twenty minutes on the treadmill (HM50EX, Daeho, Korea) for five times per week for total four weeks. The average gait velocities of subjects were 3 km/h on a slope of 10%. The experimental group walked back and the control group walked forward. The experimental group showed significant increments in variable of medial-lateral, anterior-posterior, step length, velocity compared to the pre-intervention results. In addition, the control group showed significant increments in the anterior-posterior, velocity compared to the pre-intervention results. Significant differences in the post-training gains in variable of anterior-posterior, step length, velocity were observed between the experimental group and the control group. There were positive effects of backward walking on their gait and balance ability after intervention.

• East Asian mathematical journal
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• 제24권3호
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• pp.251-261
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• 2008

Let {${\xi}_j;j\;{\geq}\;1$} be a centered strictly stationary random sequence defined by $S_0\;=\;0$, $S_n\;=\;\Sigma^n_{j=1}\;{\xi}_j$ and $\sigma(n)\;=\;33\sqrt {ES^2_n}$ where $\sigma(t),\;t\;>\;0$, is a nondecreasing continuous regularly varying function. Suppose that there exists $n_0\;{\geq}\;1$ such that, for any $n\;{\geq}\;n_0$ and $0\;{\leq}\;{\varepsilon}\;<\;1$, there exist positive constants $c_1$ and $c_2$ such that $c_1e^{-(1+{\varepsilon})x^2/2}\;{\leq}\;P\{\frac{{\mid}S_n{\mid}}{\sigma(n)}\;{\geq}\;x\}\;{\leq}\;c_2e^{-(1-{\varepsilon})x^2/2$, $x\;{\geq}\;1$ Under some additional conditions, we investigate some limsup results for the increments of partial sum processes of the sequence {${\xi}_j;j\;{\geq}\;1$}.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2299-2301
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• 1998

In this paper, a modified RBF (Radial Basis Function) neural network structure is suggested for the prediction of time series with non-linear, non-stationary characteristics. Conventional RBF neural network predicting time series by using past outputs is for sensing the trajectory of the time series and for reacting when there exists strong relation between input and hidden neuron's RBF center. But this response is highly sensitive to level and trend of time serieses. In order to overcome such dependencies, hidden neurons are modified to react to the increments of input variable and multiplied by increments(or decrements) of out puts for prediction. When the suggested structure is applied to prediction of Lorenz equation, and Rossler equation, improved performances are obtainable.