• 제목/요약/키워드: stability measure

검색결과 852건 처리시간 0.026초

바로 선 자세에서 발목과 무릎관절의 고정이 자세안정성에 미치는 영향 (Effects of Immobilization of the Ankle and Knee Joints on Postural Stability in Standing)

  • 황수진;우영근;전혜선
    • 한국전문물리치료학회지
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    • 제15권1호
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    • pp.30-37
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    • 2008
  • This study was designed to examine the effects of temporary immobilization of the ankle and knee joints on standing in healthy young adults with the use of a postural control mechanism. The subjects were twenty-four college students (12 males and 12 females, aged between 20 and 28). A Biodex balance system SD 950-302 and its software were used to measure indirect balance parameters in standing. Each subject underwent postural stability tests in 4-different joint conditions: free joints, ankle immobilization only, knee immobilization only, and ankle and knee immobilization. In addition, the postural stability test was conducted once with the subject's eyes open and once with the eyes closed conditions. For data analysis of the postural stability tests, the overall stability index, antero-posterior stability index, and medio-lateral stability index were recorded. The overall stability index (p=.000) and medial-lateral index (p=.003) were significantly greater different conditions with eyes closed in postural stability. Therefore, the eyes closed condition is expected to be used as an effective postural stability training for treatment planning in patients with unstable postures. In addition, training based on the dynamic multi-segment model can improve postural stability and is available to therapeutic programs, helping people with unstable balance to reduce their risk of falling.

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Small Dam의 斜面安定 解析 (The Analysis of the Slope Stability for the Small Dam)

  • 최기봉;배우석
    • 한국안전학회지
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    • 제19권2호
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    • pp.88-92
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    • 2004
  • The paper decribes a procedure for the evaluation of the effect of seepage force on stability of slopes. The stability of an embankment impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change of reservoir level. Seepage forces in embankments are easily determined interest is the stability following a rapid change of resrvoir level. Seepage forces in embankments are easily detemined if frictional forces are expressed in relation to hydraulic gradient I. If a piezometer is inserted into a body of embankment, the level to which fee water rises is a measure of the energy at that point.

Thyristor Rectifier for DC Arc Furnace with Enhanced Arc Stability

  • Jung, Kyungsub;Suh, Yongsug;Kim, Taewon;Park, Taejun
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 전력전자학술대회
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    • pp.498-499
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    • 2011
  • In this paper, the fundamental features of the arc stability DC arc furnace have been investigated, from the converter point of view. To compare of measurement arc data from DC arc furnace and the advanced arc simulations of magneto-hydrodynamics (MHD) and the well known Cassie-Mayr arc model have been extensively used. The MHD based arc simulation has been validated in the subcomponent level, for the free burning arc set up in the laboratory. The arc simulation predicted the arc voltage for different currents with the accuracy which satisfies engineering requirements. It has been shown that the arc current steepness at current zero determines the arc stability, and the associated peak arc resistance can be used as its quantitative measure. Based on the presented insight into the DC arc stability, a converter topology solution which realizes an optimal arc stability has been proposed. The main results presented in this paper provide a design guideline for the future DC arc furnace converter topology developments.

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결혼생활의 질과 안정성에 관련된 이론적 모형 (Theoretical Frameworks to Predict Factors Associated With the Marital Quality and Stability)

  • 김영희
    • 한국생활과학회지
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    • 제5권2호
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    • pp.53-72
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    • 1996
  • This article reviewed the research on factors associated with marital quality and stability. Three major categories of factors were described, including background and context, individual traits and behaviors, and couple interactional processes. This review highlighted findings from cross-sectional and longitudinal studies of the prediction of marital quality and stability. Particular attention was given to marital instruments and procedures that had a solid empirical foundation for understanding the concepts related to measure of marital quality and stability. Also, empirically based intervention programs that had been designed to prevent marital distress and divorce were investigated to figure out the relationship between communication factors and conflict resolution styles. Finally, three theoretical frameworks were drawn from empirical literatures, marital measurment instruments, and programs for marital strength to predict factors associated with the marital quality and stability. Recommendations for future research and implications were described.

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STABILITY THEOREM FOR THE FEYNMAN INTEGRAL APPLIED TO MULTIPLE INTEGTALS

  • Kim, Bong-Jin
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제8권1호
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    • pp.71-78
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    • 2001
  • In 1984, Johnson[A bounded convergence theorem for the Feynman in-tegral, J, Math. Phys, 25(1984), 1323-1326] proved a bounded convergence theorem for hte Feynman integral. This is the first stability theorem of the Feynman integral as an $L(L_2 (\mathbb{R}^N), L_2(\mathbb{R}^{N}))$ theory. Johnson and Lapidus [Generalized Dyson series, generalized Feynman digrams, the Feynman integral and Feynmans operational calculus. Mem, Amer, Math, Soc. 62(1986), no 351] studied stability theorems for the Feynman integral as an $L(L_2 (\mathbb{R}^N), L_2(\mathbb{R}^{N}))$ theory for the functional with arbitrary Borel measure. These papers treat functionals which involve only a single integral. In this paper, we obtain the stability theorems for the Feynman integral as an $L(L_1 (\mathbb{R}^N), L_{\infty}(\mathbb{R}^{N}))$theory for the functionals which involve double integral with some Borel measures.

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미사일 모델의 피치 동안정미계수 측정을 위한 강제진동기법의 적용 (Application of Forced Oscillation Technique for Pitch Dynamic Stability Derivatives of a Missile Model)

  • 김승필;조환기;백승욱
    • 한국군사과학기술학회지
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    • 제3권2호
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    • pp.81-87
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    • 2000
  • This paper presents an application of forced oscillation technique to measure pitch dynamic stability derivatives of a missile model in the low speed wind tunnel. The missile model is oscillated by D.C. electric servomotor with constant amplitudes and frequencies. Phase shift is determined as the difference of peak values between input and output signals from the dynamic stability balance installed at the center of gravity of the model. Stability derivatives were calculated by using phase shifts, amplitudes, forcing moments and input frequencies. Test results show the proper usage of the force oscillation technique with good damping effects.

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발전기 최대 위상각을 이용한 전력계통 과도안정도 평가 (A Method for Transient Stability Assessment using Maximum Generator Angle)

  • 이덕재;장길수;권세혁;김태균;추진부
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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    • pp.239-241
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    • 2003
  • The time domain simulation method of transient stability presents accuracy and reliability, but it demands much computational time. Therefore it is necessary to filter out very stable and very unstable cases from a large set of contingencies. Following a disturbance, the shape and magnitude of representative generator angle which is most increased after fault clearing are the measure of transient stability. This paper propose a method that is not a calculation of the exact CCT of contingency, but a fast assessment of transient stability. Also it can help operators identify transient stability immediately without analyzing the graphical results. The proposed method is applied to the KEPCO system. The PSS/E is used as a time domain simulation engine by IPLAN.

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레이저 플래쉬 방법에 의한 SiC/C계 경사기능재료의 열물성 측정 (Measurement of Thermal Properties of SiC/C Functionally Gradient Materials by Laser Flash Method)

  • 목재균;유재석
    • 대한기계학회논문집B
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    • 제20권5호
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    • pp.1679-1688
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    • 1996
  • Laser flash technique was applied to measure thermal properties of FGM made by a CVD method. System stability and reproducibility of this measuring system were proved and calibrated with glassy carbon used as reference material. Specimens was prepared by cutting FGM diagonally. Measurements were performed for a wide range of temperatures up to 1500K. Relative heat capacity of the FGM specimen was scattered with in $\pm$13% at room temperature and at high temperature above 1200K, and $\pm$3% at medium temperature range. On the other hand, thermal diffusivity data showed excellent reproducibility and stability through the whole temperature range. In conclusion, the multi-target radiometer can be applied to measure the thermal properties of non homogeneous materials like FGM.

모드분해기법을 이용한 현수교의 변위응답추정 (Estimation of displacement responses of a suspension bridge by using mode decomposition technique)

  • 장성진;김남식;김호경
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2009년도 춘계학술대회 논문집
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    • pp.320-325
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    • 2009
  • In this study, a method to estimate the suspension bridge deflection is developed using mode decomposition technique. In order to examine the suspension bridge stability against these dynamic loadings, the prediction of displacement response is very important to evaluate bridge stability. However, it is recognized that any measurement of movement for suspension bridges may be difficult for the absence of proper methods to measure the displacement response on site. This study aims at suggesting a method to estimate the displacement response from the measured strain signals in an indirect way to predict the displacement response, not a direct way to measure the displacement response. Additionally, by applying the FBG sensors with multi-point measurements not influenced by electric noise, it can be expected that the technique would be applicable to infrastructures.

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