Development of a markerless optical motion capture system for daily use of training in swimming

The main objective of this research was to develop a markerless optical motion capture system that can be used for daily use in swimming training. The butterfly stroke was targeted since it is considered bilaterally symmetric in motion. The system consisted of a segmentation process to obtain the participant’s silhouettes and a matching process to estimate the pose of the participant. A variable thresholding method was used to extract the silhouettes to solve non-uniform illumination in the recorded swimming video. Prior to the matching process, the human body was modeled as a series of nine segments to help the matching process. The model was then mapped so that it aligned with the silhouettes, which were investigated by similarity of intensity value. To minimize the degree of freedom in image matching, the available joint motion in the swimming human simulation model was used as a priori information for kinematics data of the swimming motion. As a result, the rotation angle’s correlation coefficients between the references and result of the matching process were around 0.95 for trunk, thigh, shank, upper arm, forearm, hand and 0.78 for head, hip and foot. The rotation angle and the velocity of the center of mass were put into the swimming human simulation model for a dynamics analysis. The simulation results show that the velocity obtained in the experiment corresponded to the fluid force exerted on the lower and upper limbs. Consequently, the proposed system of obtaining the joint motion of the butterfly stroke is suitable for daily training and coaching.     

The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.     

Designing,building, measuring,and testing a constant equivalent fall height terrain park jump

Previous work has presented both a theoretical foundation for designing terrain park jumps that control landing impact and computer software to accomplish this task. US ski resorts have been reluctant to adopt this more engineered approach to jump design, in part due to questions of feasibility. The present study demonstrates this feasibility. It describes the design, construction, measurement, and experimental testing of such a jump. It improves on the previous efforts with more complete instrumentation, a larger range of jump distances, and a new method for combining jumper- and board-mounted accelerometer data to estimate equivalent fall height, a measure of impact severity. It unequivocally demonstrates the efficacy of the engineering design approach, namely that it is possible and practical to design and build free style terrain park jumps with landing surface shapes that control for landing impact as predicted by the theory.     

Exhibition Showcases Tea and Wine Culture

During his state visit to France and Belgium this year, Chinese President Xi v Jinping stressed the importance of cultural origins and ties. In his speech delivered at the College of Europe, Xi took Chinese tea and Western wine as examples, noting that ＂Chinese tea＇s conservativness and restrainedness and European wine＇s vibrancy and warmth represents two different ways in enjoying life and interpreting the world.＂     

Dragon-horse Show Staged to Celebrate China- France Friendship

On October 17, a unique show of mechanical dragon-horse was unveiled at the Olympic Park in Beijing in celebration of the 50th anniversary of China-France dip-lomatic relations. The three-day event teatures an eight-act performance, with each act lasting one and half hours. On the first day, the dragon-horse and the spider came to life to appear in the Olympic venue. the two mythical each other when On the second day, beasts fought against the spider set a trap in an attempt to capture the drag- on-horse.     

Hangu Print Painting

Hangu District is located at the lower streams of nine rivers which stretch through the city of Tianjin,an industrial city neighboring Beijing.It faces Bohai Bay in the south,salt marshes in the east,vineyards in the west and vegetable fields in the north.Hangu is a beautiful town,with an ancient canal winding through it.Endowed with gorgeous sceneries and rich cultural traditions, Hangu has enjoyed a vibrant and unique art form of print painting.In the 1980s,a group of young print painters stood out in Hangu,enjoying nationwide reputation.In 1986,more than 300 pieces of Hangu print painting were on display at the     

Traditional Silk-making Skills Vanish

<正>China is the earliest nation to plant mulberry trees and breed silkworms in the world. Archaeological excavations indicate that Chinese ancestors began to gr...     

A Taste of China Chinese Cooking and Food Exhibition in France （Ⅱ）

<正>Ⅲ. Ancient Banquets and Ceremonies The information and relics of Han Dynasty (206 B.C.–220 A.D.) mainly come from tombs of that time. Many relics from the to...