球类比赛数学模拟竞技诊断的理论与实践--以乒乓球比赛分析为例

介绍了球类比赛数学模拟竞技诊断的理论与方法,并用乒乓球比赛的数学模拟竞技诊断实例进行了说明。数学模拟竞技诊断的基本思想是用一个比赛状态(技术或战术)转移概率矩阵概括地描述一场球类比赛,在此基础上通过马尔可夫链计算比赛获胜概率并进一步确定各种比赛状态(技术或战术)的竞技效率值。与传统的球类比赛分析方法相比较,数学模拟竞技诊断不但能通过各种比赛状态的转移概率对技、战术进行描述性统计分析,而且能确定各种比赛状态(技术或战术)对整场比赛获胜概率的影响。     

Age and research productivity of academic scientists

Age-publishing profiles are estimated for four fields of science using data from the 1977 Survey of Doctorate Recipients. The five measures of publishing activity used allow for analysis of the sensitivity of the age-publishing relationship to output measure. Results are presented separately for graduate faculty and faculty at nongraduate departments. Although age is found to be a fairly weak predictor of performance, in physics and earth science older scientists publish less than their youngest peers and in physiology and biochemistry older scientists publish less than their middle-aged colleagues. Given the time frame of the data, the results suggest that the graying of America's scientific community was accompanied with slowed rates of research in higher education.     

4D spinless topological insulator in a periodic electric circuit

According to the mathematical classification of topological band structures, there exist a number of fascinating topological states in dimensions larger than three with exotic boundary phenomena and interesting topological responses. While these topological states are not accessible in condensed matter systems, recent works have shown that synthetic systems, such as photonic crystals or electric circuits, can realize higher-dimensional band structures. Here, we argue that, because of its symmetry properties, the 4D spinless topological insulator is particularly well suited for implementation in these synthetic systems. We explicitly construct a 2D electric circuit lattice, whose resonance frequency spectrum simulates the 4D spinless topological insulator. We perform detailed numerical calculations of the circuit lattice and show that the resonance frequency spectrum exhibits pairs of 3D Weyl boundary states, a hallmark of the nontrivial topology. These pairs of 3D Weyl states with the same chirality are protected by classical time-reversal symmetry that squares to +1, which is inherent in the proposed circuit lattice. We also discuss how the simulated 4D topological band structure can be observed in experiments.     

Chronische Myeloproliferative Erkrankungen (CMPE)

Ohne Zusammenfassung     

What Mathematics Education May Prepare Students for the Society of the Future?

This paper attempts to engage the field in a discussion about what mathematics is needed for students to engage in society, especially with an increase in technology and digitalization. In this respect, mathematics holds a special place in STEM as machines do most of the calculations that students are taught in K-12. We raise questions about what mathematical proficiency means in today’s world and what shifts need to be made in both content and pedagogy to prepare students for 21st Century Skills and mathematical reasoning.     

Entrepreneurial orientation in turbulent environments: The moderating role of absorptive capacity

The literature on entrepreneurial orientation (EO) has confirmed the positive relationship between EO and firm performance and that relationship's dependence on several contingencies. The present study connects the resource-based view and its dynamic capability extension to introduce absorptive capacity (ACAP) as a moderator of the relationship between EO and firm performance. This theoretically derived research model is empirically validated using survey data from 219 small and medium-sized enterprises in Germany. Our empirical findings are that ACAP strengthens the EO–performance relationship in turbulent markets.