线性流形上左右逆特征值问题的最小二乘解

利用矩阵的奇异值分解,研究了线性流形上实对称矩阵的左右逆特征值的最小二乘解,得到了最小二乘解的一般表达式.对于给定的矩阵,得到了它的最佳逼近解。     

What parents say about children’s inequality of opportunities: a study in Mauritius

Longitudinal studies showing the beneficial impact of early childhood education on later academic achievement have contributed to persuading policy-makers and academia that early childhood is the best time to address inequalities. However, the voice of parents is often absent from these debates. We investigated the perspectives of parents on children’s inequalities of opportunities and on the role of education and early childhood care in equalising life chances. The study specifically explored the views of 26 parents in the sub-Saharan African country of Mauritius through focus group discussions. Findings of the study suggested that parents tend to adhere to the discourse of parental responsibility as a key factor in children’s inequalities. Yet they also showed that parents have potential to criticise and deconstruct this narrative, as they experience structural circumstances, such as poverty or discrimination, shaping their life opportunities and those of their children.     

利用三维地震及模型反演技术研究薄煤层厚度及分布范围的方法

针对薄煤层的厚度及其分布范围问题,提出应用三维地震及模型反演技术进行解决的方案,介绍了反演的主要过程及技术参数,并结合实例进行说明。     

逆半环上环同余

本文通过定义逆半环上的环同余,进行一系列推广。     

Disturbance rejection control based on acceleration projection method for walking robots

This paper presents a disturbance rejection scheme for walking robots under unknown external forces and moments. The disturbance rejection strategy, which combines the inverse dynamics control with the acceleration projection onto the ZMP （zero moment point）-plane, can ensure the overall dynamic stability of the robot during tracking the pre-computed trajectories. Under normal conditions, i.e., the system is dynamically balanced, a primary inverse dynamics control is utilized. In the case that the system becomes unbalanced due to external disturbances, the acceleration projection control （APC） loop, will be activated to keep the dynamic stability of the walking robot through modifying the input torques. The preliminary experimental results on a robot leg demonstrate that the proposed method can actually make the robot keep a stable motion under unknown external perturbations.     

基于逆概率的变精度粗糙集模型

从经典的概率粗糙集模型出发,参照Bayes因子,研究了一种基于逆概率的变精度粗糙集模型,该模型不受先验概率的影响,从而减小了决策失误的风险.     

Intersecting barriers to adolescents’ educational access during COVID-19: Exploring the role of gender,disability and poverty

This article explores the social determinants of adolescents’ access to education during the COVID-19 pandemic in three diverse urban contexts in Bangladesh, Ethiopia and Jordan. It provides novel empirical data from the Gender and Adolescence: Global Evidence longitudinal study, drawing on phone surveys (4441), qualitative interviews with adolescents aged 12–19 years (500), and key informant interviews conducted between April and October 2020. Findings highlight that the pandemic is compounding pre-existing vulnerabilities to educational disadvantage, and that gender, poverty and disability are intersecting to deepen social inequalities. The paper concludes by reflecting on policy implications for inclusive distance education in emergencies.     

Deadzone compensation based on constrained RBF neural network

In this paper, a modified adaptive neural network for the compensation of deadzone is described, and simulated on a hydraulic positioning system, in which the dynamic model is separated into a series of connection of a nonlinear (deadzone) subsystem and a linear plant. The proposed approach uses two neural networks. One is the radial basis function (RBF) neural network, which is used for identifying parameters of deadzone. Based on the penalty function used in optimization theory, a multi-objective cost function with constraint is adopted to provide the best deadzone approximation. The result is used to train the other neural network for the inverse compensation of deadzone. The RBF neural network also generates the parameters of the linear plant for the design of an adaptive controller. A convergence analysis for the network training process is also presented.     

‘Next thing you know,her hair turned green’: absurdity and uncertainty in high-stakes teacher test space

This article explores what happens behind the closed doors and in the ‘black box’ of high-stakes educational testing. Our specific concern is licensure exams that are often gatekeepers into teacher education programs and the profession. Leveraging the spatial turn across critical social theory and other disciplines, we conceptualize the test space of these exams in order to account for the powerful reach that test companies have into teacher education and the ‘ideal’ restrictive space that test takers navigate. Against this conceptual background, we share findings from a larger qualitative study to illustrate how test takers ‘practice’ test space into something more manageable and familiar by leveraging various affordances presented to them. Overall, our study accounts for the spatial dimension of high-stakes educational tests and initiates productive ways to begin thinking about the structure and agency of these spaces.     

数值分析方法与不等式的证明

利用连续函数图象的一些局部性质，结合数值分析方法给出二个不等式的证明：(1)当s∈(0，1]时，成立不等式：(1/4 4^1/s-1/4)^ss≤1．(2)当s∈(0，log54]时，成立不等式：(4^1/s-2)^1-ss≥1．