• Title/Summary/Keyword: Movement shock

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Kinematic Analysis of Dynamic Stability Toward the Pelvis-spine Distortion during Running (달리기 시 체간의 골반-척추구조변형이 동적안정성에 미치는 연구)

  • Park, Gu-Tae;Yoo, Kyoung-Seok
    • Korean Journal of Applied Biomechanics
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    • v.23 no.4
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    • pp.369-376
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    • 2013
  • The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

A Study on the Impact of Oil Price Volatility on Korean Macro Economic Activities : An EGARCH and VECM Approach (국제유가의 변동성이 한국 거시경제에 미치는 영향 분석 : EGARCH 및 VECM 모형의 응용)

  • Kim, Sang-Su
    • Journal of Distribution Science
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    • v.11 no.10
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    • pp.73-79
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    • 2013
  • Purpose - This study examines the impact of oil price volatility on economic activities in Korea. The new millennium has seen a deregulation in the crude oil market, which invited immense capital inflow into Korea. It has also raised oil price levels and volatility. Drawing on the recent theoretical literature that emphasizes the role of volatility, this paper attends to the asymmetric changes in economic growth in response to the oil price movement. This study further examines several key macroeconomic variables, such as interest rate, production, and inflation. We come to the conclusion that oil price volatility can, in some part, explain the structural changes. Research design, data, and methodology - We use two methodological frameworks in this study. First, in regards to the oil price uncertainty, we use an Exponential-GARCH (Exponential Generalized Autoregressive Conditional Heteroskedasticity: EGARCH) model estimate to elucidate the asymmetric effect of oil price shock on the conditional oil price volatility. Second, along with the estimation of the conditional volatility by the EGARCH model, we use the estimates in a VECM (Vector Error Correction Model). The study thus examines the dynamic impacts of oil price volatility on industrial production, price levels, and monetary policy responses. We also approximate the monetary policy function by the yield of monetary stabilization bond. The data collected for the study ranges from 1990: M1 to 2013: M7. In the VECM analysis section, the time span is split into two sub-periods; one from 1990 to 1999, and another from 2000 to 2013, due to the U.S. CFTC (Commodity Futures Trading Commission) deregulation on the crude oil futures that became effective in 2000. This paper intends to probe the relationship between oil price uncertainty and macroeconomic variables since the structural change in the oil market became effective. Results and Conclusions - The dynamic impulse response functions obtained from the VECM show a prolonged dampening effect of oil price volatility shock on the industrial production across all sub-periods. We also find that inflation measured by CPI rises by one standard deviation shock in response to oil price uncertainty, and lasts for the ensuing period. In addition, the impulse response functions allude that South Korea practices an expansionary monetary policy in response to oil price shocks, which stems from oil price uncertainty. Moreover, a comparison of the results of the dynamic impulse response functions from the two sub-periods suggests that the dynamic relationships have strengthened since 2000. Specifically, the results are most drastic in terms of industrial production; the impact of oil price volatility shocks has more than doubled from the year 2000 onwards. These results again indicate that the relationships between crude oil price uncertainty and Korean macroeconomic activities have been strengthened since the year2000, which resulted in a structural change in the crude oil market due to the deregulation of the crude oil futures.

A study on the pintle-tip shapes effect of nozzle flow using cold-flow test (핀틀 형상이 노즐 유동에 미치는 영향에 대한 실험적 연구)

  • Kim, Joung-Keun;Park, Jong-Ho;Lee, Jong-Hoon;Jeon, Min-Kyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.10
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    • pp.985-991
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    • 2010
  • The objective of this work was to investigate the pintle-tip shape effect on nozzle flow and thrust by cold flow test. When nozzle throat area was decreased by pintle movement, chamber pressure was increased monotonously but thrust was increased differently according to every pintle-tip shape. At the same chamber pressure and nozzle throat area, thrust of convex pintle-tip shape was mostly larger than that of concave one. Nozzle wall pressure distribution and magnitude of pintle-tip load depended on the pintle-tip shape, pintle position and nozzle throat area.

Measurement of Vibration Signals of a Gun Barrel Type Structure using Mechanical Filter (기계적 필터를 이용한 포신형상 구조물의 진동신호 측정)

  • Ryu, B.J.;Lee, G.S.;Shin, G.B.;Oh, B.J.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.181-184
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    • 2007
  • This paper deals with the method of vibration measurement of a gun barrel structure using mechanical filter. When a bullet with high speed is moving within a gun barrel type structure with low bending vibration frequencies, it is difficult to measure the bending vibration signals of the structure. For example, noncontact type sensors such as displacement or velocity sensor are not appropriate for the measurement of vibrational signals because of the movement effect of the equipment frame through the moving structures or effect of the ground vibration. One of contact type sensors such as accelerometer is profitable for measurement of vibrational signals because of its wide measurement ranges. In the case of a gun barrel structure including high vibrational signals like shock waves, however, it is necessary to propose vibration measurement method filtering high frequencies. The purpose of the paper is to propose the proper vibrational measurement technique filtering high frequencies of a gun barrel type structure.

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Behavioral Response and Immune Alterations by Electric Footshock in Mice (생쥐에서 전기자극 스트레스에 의한 행동반응과 면역 기능 변화)

  • Kim, Jung-Bum;Park, Won-Kyun;Song, Dae-Kyu
    • Korean Journal of Psychosomatic Medicine
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    • v.4 no.1
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    • pp.44-53
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    • 1996
  • The present experiment was designed to investigate the effects of behavioral, response to immune function in response to electric footshock in mice. Mice were subjected to electric footshock for 3 days(two sessions a day, 11 times of shock for about 31 minutes a session). The humoral immune response was measured using mice immunized with rat RBC. The cell-mediated immune responses were evaluated by contact hypersensitivity to 2, 4-dinitrofluorobenzene(DNFB) and by phytohemagglutin(PHA)-stimulated splenocytes proliferation assay. In stressed group, electric footshock suppressed significantly anti-rat RBC antibody production(p<0.05), but enhanced significantly $T_{48}$ relative to $T_{24}$ in contact hypersenstivry (P<.01) and T-cell proliferation response(P<.05) by PHA stimulation elative to control group. T-cell proliferation response by PHA stimulation was significantly correlated to the movement than the sensitivity and coping behavior in the mouse, in response to the electric footshock. These data supper the importance of behavioral response in stress-induced changes of immune functions.

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Asian Stock Markets Analysis: The New Evidence from Time-Varying Coefficient Autoregressive Model

  • HONGSAKULVASU, Napon;LIAMMUKDA, Asama
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.9
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    • pp.95-104
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    • 2020
  • In financial economics studies, the autoregressive model has been a workhorse for a long time. However, the model has a fixed value on every parameter and requires the stationarity assumptions. Time-varying coefficient autoregressive model that we use in this paper offers some desirable benefits over the traditional model such as the parameters are allowed to be varied over-time and can be applies to non-stationary financial data. This paper provides the Monte Carlo simulation studies which show that the model can capture the dynamic movement of parameters very well, even though, there are some sudden changes or jumps. For the daily data from January 1, 2015 to February 12, 2020, our paper provides the empirical studies that Thailand, Taiwan and Tokyo Stock market Index can be explained very well by the time-varying coefficient autoregressive model with lag order one while South Korea's stock index can be explained by the model with lag order three. We show that the model can unveil the non-linear shape of the estimated mean. We employ GJR-GARCH in the condition variance equation and found the evidences that the negative shocks have more impact on market's volatility than the positive shock in the case of South Korea and Tokyo.

Characterization of nucleotide-induced changes on the quaternary structure of human 70 kDa heat shock protein Hsp70.1 by analytical ultracentrifugation

  • Borges, Julio C.;Ramos, Carlos H.I.
    • BMB Reports
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    • v.42 no.3
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    • pp.166-171
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    • 2009
  • Hsp70s assist in the process of protein folding through nucleotide-controlled cycles of substrate binding and release by alternating from an ATP-bound state in which the affinity for substrate is low to an ADP-bound state in which the affinity for substrate is high. It has been long recognized that the two-domain structure of Hsp70 is critical for these regulated interactions. Therefore, it is important to obtain information about conformational changes in the relative positions of Hsp70 domains caused by nucleotide binding. In this study, analytical ultracentrifugation and dynamic light scattering were used to evaluate the effect of ADP and ATP binding on the conformation of the human stress-induced Hsp70.1 protein. The results of these experiments showed that ATP had a larger effect on the conformation of Hsp70 than ADP. In agreement with previous biochemical experiments, our results suggest that conformational changes caused by nucleotide binding are a consequence of the movement in position of both nucleotide- and substrate-binding domains.

Effects of Knee Joint Muscle Fatigue and Overweight on the Angular Displacement and Moment of the Lower Limb Joints during Landing (무릎 관절 근육 피로와 과체중이 착지 시 하지 관절의 각변위와 모멘트에 미치는 영향)

  • Kim, Tae-Hyeon;Youm, Chang-Hong
    • Korean Journal of Applied Biomechanics
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    • v.23 no.1
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    • pp.63-76
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    • 2013
  • The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on the angular displacement and moments of the lower limb joints during landing. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. The knee joint muscle fatigue during landing was found to increase the dynamic stability by minimizing the movements of the coronal and horizontal planes and maintaining a more neutral position to protect the knee. The effect of body weight during landing was better in the normal weight group than in the overweight group, with the lower limbs performing their shock-absorbing function in an efficient manner through increased sagittal movement. Therefore, accumulated fatigue of knee joint muscles or overweight may be highly correlated with the increase in the incidence of injury during landing after jumping, descending stairs, and downhill walking.

Multi-Point Aerodynamic Design Optimization of DLR F-6 Wing-Body-Nacelle-Pylon Configuration

  • Saitoh, Takashi;Kim, Hyoungjin;Takenaka, Keizo;Nakahashi, Kazuhiro
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.3
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    • pp.403-413
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    • 2017
  • Dual-point aerodynamic design optimization is conducted for DLR-F6 wing-body-nacelle-pylon configuration adopting an efficient surface mesh movement method for complex junction geometries. A three-dimensional unstructured Euler solver and its discrete adjoint code are utilized for flow and sensitivity analysis, respectively. Considered design conditions are a low-lift condition and a cruise condition in a transonic regime. Design objective is to minimize drag and reduce shock strength at both flow conditions. Shape deformation is made by variation of the section shapes of inboard wing and pylon, nacelle vertical location and nacelle pitch angle. Hicks-Henne shape functions are employed for deformation of the section shapes of wing and pylon. By the design optimization, drag coefficients were remarkably reduced at both design conditions retaining specified lift coefficient and satisfying other constraints. Two-point design results show mixed features of the one-point design results at low-lift condition and cruise conditions.

Effects of Landing Height and Knee Joint Muscle Fatigue on Movement of the Lower Extremity during Cutting After Landing (착지 높이와 무릎관절 근육 피로가 착지 후 방향 전환 동작 시 하지관절의 움직임에 미치는 영향)

  • Kim, You-Kyung;Youm, Chang-Hong
    • Korean Journal of Applied Biomechanics
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    • v.25 no.3
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    • pp.311-322
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    • 2015
  • Objective : The purpose of this study was to investigate the effects of landing height and knee joint muscle fatigue on the movement of the lower extremity during cutting after landing. Method : Subjects included 29 adults (age: $20.83{\pm}1.56years$, height: $172.42{\pm}9.51cm$, weight: $65.07{\pm}10.18kg$). The subjects were asked to stand on their dominant lower limb on jump stands that were 30 and 40 cm in height and jump from each stand to land with the dominant lower limb on a force plate making a side step cutting move at a $45^{\circ}$ angle with the non-dominant lower limb. The fatigue level at 30% of the knee extension peak torque using an isokinetic dynamometer. Results : The results showed that the difference of landing height increased maximum range of motion and angular velocity of hip, knee, and ankle joints in the sagittal plane, and in the angular velocity of motion of the hip joint in the sagittal plane. The maximum range of motion of the knee joint in the sagittal plane and the frontal plane decreased on landing from both heights after the fatigue exercise. The angular velocity of the hip joint in the sagittal plane, and the maximum range of motion of the hip joint in the transverse plane decreased for both landing heights after the fatigue exercise. The angular velocity of the hip joint in the frontal plane decreased for the 30 cm landing height after the fatigue exercise. On the other hand, the angular velocity and maximum range of motion of the ankle joint in the sagittal plane for both landing heights, and the angular velocity and maximum range of motion of the ankle joint in the frontal plane increased on landing from the 40 cm height after the fatigue exercise. Conclusion : Different landing heights of 30 and 40 cm and 30% fatigue of peak torque of knee extensor found a forefoot and stiff landing strategy, when cutting after landing. These results might be due to decline in the shock absorption capability of the knee joint and the movement capability related to cutting while increasing the contribution of the ankle joint, which may cause increased ankle joint injuries.