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排序方式: 共有620条查询结果,搜索用时 15 毫秒
31.
Arslan Okan Haser Çiğdem Van Zoest Laura R. 《Journal of Mathematics Teacher Education》2022,25(4):429-452
Journal of Mathematics Teacher Education - To better understand the critical early years of teaching and teacher identity development, this study explored the mathematics teacher identity of two... 相似文献
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周淑娟 《廊坊师范学院学报(自然科学版)》2011,11(2):40-43
神经网络能精确地对复杂问题进行预测,但易受训练过度的影响且训练速度慢。遗传算法是一种全局优化搜索算法,这种方法的要求是拟合度函数必须收敛于最小误差,这为具体的实现方案留下了许多自由空间。将遗传算法与神经网络结合起来使用可以在较高的层次上提高模型的可理解性。 相似文献
34.
Stephanie M. Curenton Shana E. Rochester Jacqueline Sims Nneka Ibekwe-Okafor Iheoma U. Iruka Arlene G. García-Miranda Jessica Whittaker 《Child development》2022,93(3):681-698
This study used secondary data from the My Teaching Partner-Math/Science 2013–2016 randomized control trial to explore whether equitable sociocultural classroom interactions (see Curenton et al., 2019) were associated with the skills of 105 four- and five-year-olds (52% boys; drawn from 20 unique video recordings of preschool teachers/classrooms; 43% were Black, Latine, Asian, or other racially marginalized learners). Equitable interactions predicted children's skills with effect sizes ranging from small (0.01–0.44) to large (1.00). Moderation analyses revealed that when classrooms had more racially marginalized learners, teachers’ use of equitable disciplinary and personalized learning practices were associated with higher executive functioning gains across prekindergarten. Findings illustrate how classroom composition can be a key indicator between equitable classroom interactions and young children's early skills. 相似文献
35.
Bonacci J Saunders PU Alexander M Blanch P Vicenzino B 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(1):59-71
Running is the most important discipline for Olympic triathlon success. However, cycling impairs running muscle recruitment and performance in some highly trained triathletes; though it is not known if this occurs in elite international triathletes. The purpose of this study was to investigate the effect of cycling in two different protocols on running economy and neuromuscular control in elite international triathletes. Muscle recruitment and sagittal plane joint angles of the left lower extremity and running economy were compared between control (no preceding cycle) and transition (preceded by cycling) runs for two different cycle protocols (20-minute low-intensity and 50-minute high-intensity cycles) in seven elite international triathletes. Muscle recruitment and joint angles were not different between control and transition runs for either cycle protocols. Running economy was also not different between control and transition runs for the low-intensity (62.4 +/- 4.5 vs. 62.1 +/- 4.0 ml/min/kg, p > 0.05) and high-intensity (63.4 +/- 3.5 vs. 63.3 +/- 4.3 ml/min/kg, p > 0.05) cycle protocols. The results of this study demonstrate that both low- and high-intensity cycles do not adversely influence neuromuscular control and running economy in elite international triathletes. 相似文献
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The transport of thermal energy in thermodynamics is described as the product of entropy flow and of the absolute temperature, in analogy to the volume flow and pressure in oil hydraulics and to electric charge flow (= current) and voltage in electronics. Bond graphs are shown to be especially suitable to describe the splitting of applied thermal energy into internal energy and external mechanical work. Transformers and the 0- and 1-junctions of Paynter can illustrate various entropy flow processes, including Carnot engines and heat exchangers. Entropy flow in heat conduction is distinguished from entropy convection, or transport by moving mass, where the entropy/temperature characteristic or equation of state is important. Irreversibilities are represented by impedance transformers reducing temperature and increasing entropy flow but conserving power. 相似文献
38.
Meena Desai U. M. Donde M. Ikram Khatkhatay 《Indian journal of clinical biochemistry : IJCB》2001,16(1):127-131
Baseline data available on the excretory profiles of estrone giucuronide (E1G), pregnanediol glucuronide (PdG) and luteinising hormone (LH) on human menstrual cycles (n=104) was retrospectively analysed
for identifying the limits of fertile period (FP) to be used as natural method of family planning. The limits of fertile period
are suggested based on centile distribution of E1G and PdG levels during defined phase of menstrual cycle. Two approaches, which do not involve any mathematical calculation
are suggested. In approach A, fertile period is said to have started when E1G value of 35 ng/ml is reached and is said to have ended when the PdG value of 2 μg/ml on two consecutive days is obtained.
The criteria were applied to 30 test cycles in whom authentic fertile period was identified based on excretory profiles of
E1G, PdG and LH throughout the menstrual cycles. When approach A was followed the authentic fertile period was covered in 27
cycles giving an accuracy of 90% with a mean fertile period length of 9.11+1.9 days. In approach B, the cut off limit of E1G value was increased to 55 ng/ml in order to reduce the days of abstinence. Though the length of the fertile period was reduced
to 7.2+1.5 days the accuracy of the approach was 66.6%. Thus the approach A which has accuracy of 90% may appeal to determined
couples who wish to practice family planning by periodic abstinence or restrict the use of barrier methods. 相似文献
39.
Zhouchao Wei Amin Yousefpour Hadi Jahanshahi Uǧur Erkin Kocamaz Irene Moroz 《Journal of The Franklin Institute》2021,358(1):814-833
Having found hidden hyperchaos in a 5D self-exciting homopolar disc dynamo, we study the existence of a Hopf bifurcation, which leads to unstable limit cycles bifurcating from a stable equilibrium. Hidden chaos with only stable equilibria can be observed from the Hopf bifurcation: a typical way to enable hidden attractors to be located. We then provide a new fuzzy controller, and a fast fuzzy disturbance observer, based on terminal sliding mode control for synchronization of the hyperchaotic system. Fuzzy inference is considered to weaken the chattering phenomena. Using Lyapunov stability theory, the stability of the closed-loop system is proved. Finally, simulations of synchronization are illustrated to show the efficient performance of the designed control method via external disturbances and dynamic uncertainties. 相似文献
40.