KINEMATICS OF PUSH-HAND STRUGGLE IN TAI CHI CHUAN

The push hand in Tai Chi Chuan is a practice of tactile sense to make the opponents lost their own balance. The interaction of Tai Chi masters and their opponents during performing push hands is still unknown. The purpose of this study was to investigate the kinematics of both participants during fixed-steps push-hand struggle in Tai Chi Chuan. Six male subjects, divided into three couples, were involved in this study. Three dimensional kinematic data during push hand were collected by VICON motion analysis system and were analyzed by Visual3D software. The results showed that the winner made the opponent lost his balance to move step in the attacked mode and the defensive mode. In summary, the winner in the push hand competition had less movement of center of mass in vertical direction and rotated the waist to prevent the balance lost

Characterizing Intermittency of 4-Hz Quasi-periodic Oscillation in XTE J1550-564 using Hilbert-Huang Transform

We present the time-frequency analysis results based on the Hilbert-Huang transform (HHT) for the evolution of a 4-Hz low-frequency quasi-periodic oscillation (LFQPO) around the black hole X-ray binary XTE J1550-564. The origin of LFQPOs is still debated. To understand the cause of the peak broadening, we utilized a recently developed time-frequency analysis, HHT, for tracking the evolution of the 4-Hz LFQPO from XTE J1550 564. By adaptively decomposing the ~4-Hz oscillatory component from the light curve and acquiring its instantaneous frequency, the Hilbert spectrum illustrates that the LFQPO is composed of a series of intermittent oscillations appearing occasionally between 3 Hz and 5 Hz. We further characterized this intermittency by computing the confidence limits of the instantaneous amplitudes of the intermittent oscillations, and constructed both the distributions of the QPO's high and low amplitude durations, which are the time intervals with and without significant ~4-Hz oscillations, respectively. The mean high amplitude duration is 1.45 s and 90% of the oscillation segments have lifetimes below 3.1 s. The mean low amplitude duration is 0.42 s and 90% of these segments are shorter than 0.73 s. In addition, these intermittent oscillations exhibit a correlation between the oscillation's rms amplitude and mean count rate. This correlation could be analogous to the linear rms-flux relation found in the 4-Hz LFQPO through Fourier analysis. We conclude that the LFQPO peak in the power spectrum is broadened owing to intermittent oscillations with varying frequencies, which could be explained by using the Lense-Thirring precession model.Comment: 27 pages, 9 figures, accepted for publication in The Astrophysical Journa

GROUND REACTION FORCE ANALYSIS FOR DIFFERENT FEET POSITION IN BASKETBALL DEFENSIVE-SHUFFLE

INTRODUCTION: There are several steps for defending in basketball competition. Defender must shuffle toward lateral rear to defend. We want to understand how the different defensive steps works when defence. The purpose of this study was to collect the ground reaction force while defender shuffling toward lateral rear to find the differences of the different feet position, which we can find the optimal strategy to stop opponent cutting and moving

THE KINEMATICS CHAIN OF INSTEP KICKING OF SOCCER WITH UPPERBODY CONSTRAINED: A PILOT STUDY

The purpose of this study was to understand the kicking performance when the upperbody motion has been limited. One player in the college cup level A volunteered to participate in this study (Aged: 20 years, Height: 172 cm, Body mass: 65 kg). A VICON motion capture system (200 Hz) was used to capture the kicking motion. The participant was asked to kick the ball both using an arm swing and not using an arm swing. The Visual3D was used to calculate the segment velocity, angular velocity, and kinetic chain. The results indicated that kicking with arm swing had a greater ball and lower-extrimity segment velocity. The main effect for lower ball velocity during kicking without arm swing is the decreased angular velocity at the ankle joint. When arm motion has been limited, players should noticed that the ankle joint needs to follow through after foot-ball contact

The Influence of Customer’s Sharing Behavior in Social Commerce

All transaction behaviors between enterprises and customers directly take place on social media. Using social media for people to interact with their friends and family become a routine in the daily life. This study aims to figure out the critical factors and relations of brand community and social commerce. Meanwhile, this study is to investigate the influence on consumers’ engagement by considering the building of a brand community for social commerce. This study reviews many key literatures of social commerce and brand community. This study employs a survey base strategy to figure out the proposed research questions