• Title/Summary/Keyword: Maximum Range

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The Effect of Different Sitting Postures on Range of Motion, Strength and Proprioceptive Sense of Neck (다른 앉은 자세가 목의 관절가동범위, 근력, 고유수용성 감각에 미치는 영향)

  • Jung, Ji-Moon;Gu, Ja-Shin;Shin, Won-Seob
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.5
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    • pp.2212-2218
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    • 2012
  • The purpose of this study was to investigate the influence of different sitting postures on range of motion, strength and proprioceptive sense of neck. Fifteen healthy university students participated in the study. Depending on upright sitting position and slump sitting position, range of motion and joint position sense were measured by using Dualer IQ. Also, the maximum isometric strength and force sense were measured by using linear force. As a result, we found that the maximum angle of neck extension and the maximum isometric strength at flexion were significantly higher in upright posture than in slump posture. Also, the maximum angle of neck flexion and the maximum isometric strength at extension were higher in slump posture than in upright posture. According to the result, proper proprioception can have an beneficial effect on postural revision of neck and body by providing the information that cognize the position of head through and sustain upright posture.

Effect of Balance before and after Impact on the Velocity and Angle of Golf Club during Driver Swing (골프 드라이버 스윙 시 임팩트 전·후 신체 균형성이 클럽헤드의 속도와 각도에 미치는 영향)

  • Ryu, Ji-Seon;Kim, Tae-Sam
    • Korean Journal of Applied Biomechanics
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    • v.21 no.4
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    • pp.411-420
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    • 2011
  • The purpose of this investigation was to determine whether correlations exist between balance and impact velocity, angular position, and maximum velocity of a club during drive swing. Twelve skilled golfers were recruited in this study. They were asked to perform ten swing trials and two trials were selected for analysis. Balance parameters were calculated via the force platform while kinematic variables were determined by using the Qualisys system. The results of the present study demonstrated that the average of COP velocity was faster in the medio-lateral direction rather than the anterio-posterior direction. Also, left foot's COP velocity and free torque were greater than the right foot's before impact. The range of the right foot's COP in the anterio-posterior direction before impact were correlated with the club velocity and angular position at impact. There was a negative correlation between the left foot's COP velocity before the impact and the velocity at impact. Additionally, the range and RMS of the left foot's free torque affected on the club angular position at impact and the maximum velocity at release, respectively. Finally, a negative correlation existed between the range of the right foot's free torque after the impact and club's maximum velocity at release.

The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

  • Xu, Shi-Zhou;He, Feng-You
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1598-1611
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    • 2016
  • In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

Seismic performance and optimal design of framed underground structures with lead-rubber bearings

  • Chen, Zhi-Yi;Zhao, Hu;Lou, Meng-Lin
    • Structural Engineering and Mechanics
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    • v.58 no.2
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    • pp.259-276
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    • 2016
  • Lead-rubber bearings (LRBs) have been used worldwide in seismic design of buildings and bridges owing to their stable mechanical properties and good isolation effect. We have investigated the effectiveness of LRBs in framed underground structures on controlling structural seismic responses. Nonlinear dynamic time history analyses were carried out on the well-documented Daikai Station, which collapsed during the 1995 Hyogoken-Nanbu earthquake. Influences of strength ratio (ratio of yield strength of LRBs to yield strength of central column) and shear modulus of rubber on structural seismic responses were studied. As a displacement-based passive energy dissipation device, LRBs reduce dynamic internal forces of framed underground structures and improve their seismic performance. An optimal range of strength ratios was proposed for the case presented. Within this range, LRBs can dissipate maximum input earthquake energy. The maximum shear and moment of the central column can achieve more than 50% reduction, whereas the maximum shear displacement of LRBs is acceptable.

A Study on the Maximum Target Distance Using a Flight Simulator of Glide-Type Ammunition (활공형 탄약의 비행모사 시뮬레이터를 활용한 조건별 최대사거리 연구)

  • Shin, Seung-je;Kim, Whan-Woo
    • Journal of Korea Multimedia Society
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    • v.21 no.6
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    • pp.698-704
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    • 2018
  • When the new ammunition is designed, it is necessary to confirm in advance how long the target distance is depends on the shape and weight of the designed ammunition. Therefore we can use commercial software such as PRODAS to predict the target distance in the design stage. This commercial software has aerodynamic data for various ammunition shape and calculates the target range by calculating the kinetic equations of the ammunition using the aerodynamic data most similar to the designed ammunition. The ammunition for predicting the target distance through software such as PRODAS is a non-guided ammunition that has no control after launch but the glide type ammunition is guided and control ammunition. So it is predicts the state of ammunition after the launch. A new type of simulator is needed to analyze the maximum range and to verify the onboard guided and control algorithm. The simulator constructed in this paper is an optimized simulator for glide type ammunition. Unlike unmanned aircraft and guided missiles. The rotation characteristics of the ammunition are considered and the navigation initialization algorithm is applied. The constructed simulator confirmed the performance by performing maximum range analysis of glide type ammunition.

A Study on Variation of Colony Forming Units of Fungi by Input Ratios of Wood Chips in Aerobic Composting of Food Wastes (음식물류폐기물의 호기성 퇴비화에 있어서 목재세편의 투입비에 따른 곰팡이의 균락형성단위의 변화에 관한 연구)

  • Park, Seok-Hwan
    • Journal of Environmental Health Sciences
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    • v.33 no.5
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    • pp.451-455
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    • 2007
  • This study was performed to evaluate the effects of input ratios of bulking material in aerobic composting of food wastes on variation of colony forming units(CFU) of fungi. Wood chips were used as a bulking material. Volume ratios of food wastes to wood chips in reactor of Control, WC-1 and WC-2 were 10/0, 10/5 and 10/10, respectively. Reactors were operated for 24 days with I hour stirring by 1rpm and 2 hours of the forced aeration rate of $80L/min{\cdot}m^3$ per day. WC-2 reached high temperature range faster than WC-1, and the maximum temperature of WC-2 was higher than that of WC-1. WC-2 reached high pH range faster than WC-1. and the maximum pH of WC-2 was higher than that of WC-1. WC-2 reached high Log(CFU/gram) range faster than WC-I, and the maximum Log(CFU/gram) of WC-2 was higher than that of WC-1. These all mean that the reaction velocity of composting of WC-2 was faster than that of WC-1. The profile of fungi changes in Log(CFU/gram) was similar to that of temperature changes (r=0.8861) not pH changes (r=0.1631).

A Method to Determine Optimum Viscoelastic Layer Thickness of Sandwich Plate for Maximum Modal Damping (샌드위치 평판의 모드 감쇠 최대화를 위한 점탄성층 두께 결정법)

  • Nam, Dae-Ho;Shin, Yun-Ho;Kim, Kwang-Joon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.7 s.112
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    • pp.690-696
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    • 2006
  • Thickness of damping layer in sandwich plate needs to be optimized in order to make modal loss factor of the sandwich plate maximum. Since previous studies were interested in noise reductions over high frequency range, the modal properties were derived based on simply supported boundaries. This conventional formula is approximately applicable to other boundary conditions over high frequency range only. The purpose of this study is to propose a method to determine optimum damping layer thickness of sandwich plate for maximum modal damping in low frequency range when the boundary condition is not a simple support. The conventional RKU equation based on simply supported boundary is modified to reflect other boundary conditions and the modified RKU equation is subsequently applied to determine the optimum damping layer thickness for arbitrary conditions. In order to reflect frequency-dependent characteristics of elastic modulus of the damping layer, an iteration method is proposed in determining the modal properties. Test results on sandwich plates for optimum damping layer thickness are compared with predictions by the proposed method and conventional method.

Fatigue Life Prediction Model of 12% Cr Rotor Steel (12% 크롬 로터강의 피로수명 예측 모델에 관한 연구)

  • 장윤석;오세욱;오세규
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1349-1355
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    • 1990
  • By examining the fatigue deformation properties of 12% Cr rotor steel which has been proved to have high fatigue and creep rupture strength around 600deg. C, authors reviewed major fatigue life prediction models such as Manson, Langer and Morrow equations, and following results were obtained. (1) A simple life prediction model for 12% Cr rotor steel was obtained as follows : DELTA..epsilon.$_{t}$ =2.18+.sigma.$_{u}$ /E+ $N^{-0.065}$+ $e^{0.6}$ $N^{-0.025}$ This equation shows that fatigue life, N, can be easily determined when total strain range, DELTA..epsilon.$_{t}$ and ultimate tensile strength, .sigma.$_{u}$ are known by simple tension test on the given test conditions. (2) Life prediction equation with equivalent maximum stress, DELTA..sigma./2, corresponding maximum strain in one cycle at room temperature is as follows: DELTA..sigma./w=-7.01logN+96.69+96.69

Long Term Average Spectral Analysis for Acoustical Discrimination of Korean Nasal Consonants (한국어 비음의 음향학적 구분을 위한 장구간 스펙트럼(LTAS) 분석)

  • Choi, Soon-Ai;Seong, Cheol-Jae
    • MALSORI
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    • no.60
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    • pp.67-84
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    • 2006
  • The purpose of this study is to find some acoustic parameters on frequency domain to distinguish the Korean nasals, $/m,\;n,\;{\eta}/$ from each other. The new parameters are devised on the basis of LTAS (Long Term Average Spectrum). The maximum peak amplitude and the relevant formant frequency are measured in low and high frequency range, respectively. The frequency of spectral valley and its energy level are also obtained in the specific frequency range of the spectrum. Spectral slope, total energy value in specific frequency range, statistical distribution of spectral energy like centroid, skewness, and kurtosis are suggested as new parameters as well. The parameters that show statistically significant differences across nasals are summerized as follows. 1) in syllable initial positions: the total energy value from 1,500 to 2,200 Hz(zeroENG); 2) in syllable final positions: the peak amplitude of the first formant(peak1_a), the formant frequency with maximum peak amplitude from 4,000 to 8,000 Hz(peak2_f), the maximum peak amplitude of the formant frequency from 4,000 to 8,000 Hz(peak2_a), and the total energy value from 1,500 to 2,200 Hz(zeroENG).

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Time-optimal Trajectory Planning for a Robot System under Torque and Impulse Constraints

  • Cho, Bang-Hyun;Choi, Byoung-Suk;Lee, Jang-Myung
    • International Journal of Control, Automation, and Systems
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    • v.4 no.1
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    • pp.10-16
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    • 2006
  • In this paper, moving a fragile object from an initial point to a specific location in the minimum time without damage is studied. In order to achieve this goal, initially, the maximum acceleration and velocity ranges are specified. These ranges can be dynamically generate on the planned path by the manipulator. The path can be altered by considering the geometrical constraints. Later, considering the impulsive force constraint on the object, the range of maximum acceleration and velocity are obtained to preserve object safety while the manipulator is carrying it along the curved path. Finally, a time-optimal trajectory is planned within the maximum allowable range of acceleration and velocity. This time-optimal trajectory planning can be applied to real applications and is suitable for both continuous and discrete paths.