Networking retinomorphic sensor with memristive crossbar for brain-inspired visual perception     

Shuang Wang  Chen-Yu Wang  Pengfei Wang  Cong Wang  Zhu-An Li  Chen Pan  Yitong Dai  Anyuan Gao  Chuan Liu  Jian Liu  Huafeng Yang  Xiaowei Liu  Bin Cheng  Kunji Chen  Zhenlin Wang  Kenji Watanabe  Takashi Taniguchi  Shi-Jun Liang  Feng Miao 《国家科学评论(英文版)》2021,8(2)

Compared to human vision, conventional machine vision composed of an image sensor and processor suffers from high latency and large power consumption due to physically separated image sensing and processing. A neuromorphic vision system with brain-inspired visual perception provides a promising solution to the problem. Here we propose and demonstrate a prototype neuromorphic vision system by networking a retinomorphic sensor with a memristive crossbar. We fabricate the retinomorphic sensor by using WSe₂/h-BN/Al₂O₃ van der Waals heterostructures with gate-tunable photoresponses, to closely mimic the human retinal capabilities in simultaneously sensing and processing images. We then network the sensor with a large-scale Pt/Ta/HfO₂/Ta one-transistor-one-resistor (1T1R) memristive crossbar, which plays a similar role to the visual cortex in the human brain. The realized neuromorphic vision system allows for fast letter recognition and object tracking, indicating the capabilities of image sensing, processing and recognition in the full analog regime. Our work suggests that such a neuromorphic vision system may open up unprecedented opportunities in future visual perception applications.  相似文献   

Adverse effects of energy restriction on myogenic enzymes in judoists     

Takashi Umeda  Shigeyuki Nakaji  Tadashi Shimoyama  Youske Yamamoto  Manabu Totsuka  Kazuo Sugawara 《Journal of sports sciences》2013,31(4):329-338

In this study, we examined the effects of weight reduction by restricting energy intake on muscle function and serum concentrations of myogenic enzymes in judoists. Twenty-seven male judoists aged 19.3±0.6 years (mean±s) were divided into three groups based on the extent of body weight reduction: high weight reduction (height 1.70±0.05?m, body mass 78.5 ±13.6?kg), low weight reduction (height 1.70±0.05?m, body mass 80.7±13.1?kg) and a group that maintained body weight while continuing to perform exercise training (height 1.78± 0.07?m, body mass 78.7±8.8?kg). Body composition, blood biochemistry, energy intake and anaerobic power were assessed on four occasions: 20 days (baseline data), 4 days and 1 day before and 7 days after competition. Compared with baseline, body mass and fat-free mass were significantly lower 1 day before competition in the high and low weight reduction groups (both P?<0.01); these changes persisted for 7 days after competition in the high weight reduction group. Serum creatine kinase was significantly elevated 1 day before competition in all groups (all P?<0.05), and remained higher 7 days after competition in both the high and low weight reduction groups. Compared with baseline, maximal anaerobic power was significantly lower 1 day before competition only in the high weight reduction group (P?<0.01). Our results suggest that energy restriction in addition to intense exercise training before major competition has an adverse effect on anaerobic power and elevates serum creatine kinase concentration, leading to an impairment of muscular function and an increased susceptibility of muscle tissue to injury.  相似文献   

Electromyographic analysis of hip adductor muscles in soccer instep and side-foot kicking     

Kohei Watanabe  Hiroyuki Nunome  Koichiro Inoue  Takahiro Iga  Hiroshi Akima 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(3):295-306

ABSTRACT

A possible link between soccer-specific injuries, such as groin pain and the action of hip adductor muscles has been suggested. This study aimed to investigate neuromuscular activation of the adductor magnus (AM) and longus (AL) muscles during instep and side-foot soccer kicks. Eight university soccer players performed the two types of kick at 50%, 75% and 100% of the maximal ball speed. Surface electromyography (EMG) was recorded from the AM, AL, vastus lateralis (VL) and biceps femoris (BF) muscles of both kicking and supporting legs and the kicking motions were three-dimensionally captured. In the kicking leg, an increase in surface EMG with an increase in ball speed during instep kicking was noted in the AM muscle (p < 0.016), but not in AL, VL or BF muscles (p > 0.016). In the supporting leg, surface EMG of both AM and AL muscles was significantly increased with an increase in the ball speed before ball impact during both instep and side-foot kicks (p < 0.016). These results suggest that hip adductor muscles markedly contribute to either the kicking or supporting leg to emphasise the action of soccer kicks.  相似文献   

元代科举的“策问”和“对策”   总被引：2，自引：0，他引：2  

渡边健哉 《考试研究》2009,(2):100-115

元代科举除了关乎经义和古赋问题以外,还包括一道“策”题。“策”即“经史、时务内出题,不矜浮藻,惟务直述,限一千字以上”。本论文着眼于“策”,以元代举业书《新刊类编历举三场文选》中收录的策问和解答为线索,考察应试者对现实社会政治课题的认识能力,也从一个侧面反映元代中期的社会状况。  相似文献   

Aerodynamic force data for a V-style ski jumping flight     

K.?SeoEmail author  I.?Watanabe  M.?Murakami 《Sports Engineering》2004,7(1):31-39

To determine the flight of a ski jumper it is essential to know what aerodynamic forces are acting on the ski jumper. However, few data on this are available, especially for a V-style ski jumping flight. We have measured the aerodynamic forces during the free flight phase for a V-style, as well as a parallel-style, ski jump by employing a full-size model in a wind tunnel. The aerodynamic force data, (drag, lift and pitching moment) were obtained to create an aerodynamic database. These forces are given in polynomial form as functions of the angle of attack, the body-ski (forward leaning) angle and the ski-opening (V-style) angle. Using the polynomial form database is a convenient way of obtaining the aerodynamic forces. Moreover, the wind tunnel was equipped with a ground effect plate to measure the aerodynamic forces during the landing phase. It was found that the difference between the lift with and without the ground effect plate increases with the ski-opening angle. The longitudinal stability in the pitching motion of a body-ski combination is also discussed on the basis of the pitching moment data. This indicates that a stable pitching oscillation of the body-ski combination may arise around an equilibrium point in the angle of attack, the trim angle of attack, during flight.  相似文献   

The effects of resistance exercise with and without different degrees of blood-flow restriction on perceptual responses     

Jeremy P. Loenneke  Daeyeol Kim  Christopher A. Fahs  Robert S. Thiebaud  Takashi Abe  Rebecca D. Larson 《Journal of sports sciences》2015,33(14):1472-1479

The aim was to compare exercise with and without different degrees of blood-flow restriction on perceived exertion (RPE) and discomfort. Participants were assigned to Experiment 1, 2, or 3. Each completed protocols differing by pressure, load, and/or volume. RPE and discomfort were taken before and after each set. For pressure and RPE, the 20% one repetition maximum (1RM) blood-flow restriction conditions were affected by increasing the pressure from 40% to 50% blood-flow restriction (~12 vs. ~14). This did not appear to happen within the 30% 1RM blood-flow restriction conditions or the higher pressures in the 20% 1RM conditions. The similar RPE between 20% and 30% 1RM to failure was expected given both were to failure. For discomfort, ratings were primarily affected by load at the lowest pressure. Increasing pressure to 50% blood-flow restriction increased discomfort at 20% 1RM (~2.6 vs. ~4). There was a further increase when increasing to 60% blood-flow restriction (~4 vs. ~4.8). The high-load condition had the lowest discomfort, while ratings were highest with 20% 1RM to failure. In conclusion, exercise with blood-flow restriction does not appear to augment the perceptual response observed with low-load exercise to failure.  相似文献   

日本的教育经济学:实证分析的展望和课题(续)     

小盐隆士  妹尾涉  徐国兴 《教育与经济》2004,(3):52-57

本总结了迄今为止日本教育经济学中实证研究的成果，探讨了今后需要进一步研究的课题。本从以下几个方面阐述了日本教育经济学的发展，即人力资本理论和教育收益率、劳动市场与教育、教育成果的成因分析、教育产业分析、教育需求的决定因素等，并比较各类研究的目的、方法、结论和政策意义。虽然以上每一个方面都积累了很多研究成果，可是由于资料的限制，教育经济学中的实证研究尚存在着许多有待进一步研究的课题。  相似文献   

Air pollution control for a green future     

Xiang Gao  Cheng-hang Zheng  Takashi Sagawa  Meenakshisundaram Sankar  Changyu Wu  Enrico Tronconi 《浙江大学学报(A卷英文版)》2018,19(1):1-4

  相似文献   

Combined effects of pre-cooling and water ingestion on thermoregulation and physical capacity during exercise in a hot environment   总被引：2，自引：1，他引：1  

Hasegawa H  Takatori T  Komura T  Yamasaki M 《Journal of sports sciences》2006,24(1):3-9

The aim of the present study was to determine the combined effects of pre-cooling and water ingestion on thermoregulatory responses and exercise capacity at 32 degrees C and 80% relative humidity. Nine untrained males exercised for 60 min on a cycle ergometer at 60% maximal oxygen uptake (VO2max) (first exercise bout) under four separate conditions: No Water intake, Pre-cooling, Water ingestion, and a combination of pre-cooling and water ingestion (Combined). To evaluate the efficacy of these conditions on exercise capacity, the participants exercised to exhaustion at 80% VO2max (second exercise bout) following the first exercise bout. Rectal and mean skin temperatures before the first exercise bout in the Pre-cooling and Combined conditions were significantly lower than in the No Water and Water conditions. At the end of the first exercise bout, rectal temperature was lower in the Combined condition (38.5 +/- 0.1 degrees C) than in the other conditions (No Water: 39.1 +/- 0.1 degrees C; Pre-cooling: 38.7 +/- 0.1 degrees C; Water: 38.8 +/- 0.1 degrees C) (P < 0.05). Heat storage was higher following pre-cooling than when there was no pre-cooling (P < 0.05). The final rectal temperature in the second exercise bout was similar between the four conditions (39.1 +/- 0.1 degrees C). However, exercise time to exhaustion was longer (P < 0.05) in the Combined condition than in the other conditions. Total sweat loss was less following pre-cooling than when there was no pre-cooling (P < 0.001). Evaporative sweat loss in the Water and Combined conditions was greater (P < 0.01) than in the No Water and Pre-cooling conditions. Our results suggest that the combination of pre-cooling and water ingestion increases exercise endurance in a hot environment through enhanced heat storage and decreased thermoregulatory and cardiovascular strain.  相似文献   

Kinetic function of the lower limbs during baseball tee-batting motion at different hitting-point heights     

Kazumichi Ae  Sekiya Koike  Takashi Kawamura 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(4):452-466

ABSTRACT

The aim of this study was to investigate the kinetic functions of the lower limbs at different hitting-point heights to provide key information for improving batting technique in baseball players. Three-dimensional coordinate data were acquired using a motion capture system (250 Hz) and ground reaction forces were measured using three force platforms (1000 Hz) in 22 male collegiate baseball players during tee-batting set at three different hitting-point heights (high, middle, and low). Kinetic data were used to calculate joint torque and mechanical work in the lower limbs by the inverse dynamics approach. The peak angular velocity of the lower trunk about the vertical axis was smaller under the low condition. The joint torques and mechanical works done by both hip adduction/abduction axes were different among the three conditions. These results indicate that hip adduction/abduction torques mainly contribute to a change in the rotational movement of the lower body about the vertical axis when adjusting for different hitting-point heights. In order to adjust for the low hitting-point height which would be difficult compared with other hitting-point heights, batters should focus on rotating the lower trunk slowly by increasing both hip abduction torques.  相似文献