《线性代数》研究型教学初探

在研究型教学中,恰到好处的教学设计,不仅可以加深学生对教材知识点的认识和掌握,而且对激发学生研究兴趣和培养其研究创新能力都至关重要.以《线性代数》教学为例,就如何构建全方位、立体式研究型教学,在教学设计方面谈了几点粗浅的看法,并给出了若干具体的实践案例.求教于同行,欢迎批评指正.     

关于理工科高等数学研究型教学与大学生创新意识培养研究的构想

由于高等数学是高校理工科一门重要的基础课,因此进行高等数学研究型教学与大学生创新意识培养研究是当今高校理工科专业高等数学教学中进行素质教育的必然要求.本文论述了其研究的目的、理论依据和意义,同时阐述了研究型教学与创新意识的培养问题研究的现状和趋势.最后提出了理工科高等数学研究型教学与大学生创新意识培养研究的实施方案和计划、实施细则、效益分析和研究环境.     

"生物数学"本、硕一体化系列课程的研究与探索 ——兼谈数学建模能力培养之途径

以东北林业大学本、硕两阶段"生物数学"系列课程的整体改革实践为例,针对数学本科专业和数学硕士点学科拔尖人才创新能力培养问题,通过构建"理论学习—专题研究—课外研讨班"一体化教学体系的教学法实践,探讨了如何以生物问题为背景,构建"问题—建模—求解"的研究型教学模式、搭建培养数学建模能力平台的问题,以实现培养学生数学建模能力的一体化教学体系和研究型教学模式的目标.     

基于问卷调查数据的某研究型综合性大学教师口碑的影响因素统计分析

基于某研究型综合大学本科生的"大学教师口碑在大学生群体中的生成与传播"问卷调查数据,使用因子分析对自变量降维,结合Logistic回归对调查数据进行统计建模与分析,主要解决以下两个问题:一、分析教师口碑影响因素及影响程度,得到了影响因子:学生背景因子(专业与性别)、教师教学能力因子(教学关注度与亲和度)、教师严格程度因子(考勤频率和评分高低)及教师魅力因子(教师形象与声誉、课堂互动情况);二、根据学生所获教师口碑信息预测选课情况,Logistic回归模型回代预测准确率较高。     

高等数学课程教学方法的优化及其案例

在高校公共数学课的教学中,优化教学方法是提高教学效果和教学质量的一条重要途径.提供了高等数学课程中运用讨论型、研究型教学方法的一些具体思路,并给出了在实际教学中的几则教学案例.教学实践表明,在高等数学教学中恰当地使用讨论型、研究型教学方法,可以有效促进学生创新思维的培养和综合素质的提升.     

概率论与数理统计研究型教学的案例分析

通过娃哈哈赠券收集的案例分析提出了概率论与数理统计习题课研究型教学的概念和方法,展示了概率论与数理统计在社会生活领域的一些生动应用.通过以案例驱动开展研究型教学实现了习题课课堂教学的趣味性,体现了知识的实用性,激发了学生们的学习兴趣和协作探究意识,进一步将自主学习和协作探究相结合提升了课堂的教学效果,培养了学生的数学思维习惯.     

关于数学公式教学的几点思考

数学公式反映了数学对象的属性之间的关系,公式中的字母是数学对象高度概括的具体表征.许多数学知识是通过数学公式来呈现的,从知识构建层面来看,数学公式的生成过程即是数学知识的生成过程.学生对数学公式的理解程度决定了其对数学知识的达成度.实际上一些教师不注重数学公式的推导过程或推导不到位,导致学生对知识的理解处于"饥饿"或"吃夹生饭"状态,这显然对学生的思维发展是极为不利的.教师应对数学公式的教学给予充分的关注,本文就结合教学实践谈谈数学公式教学的几点思考,敬请各位同行不吝指正.     

把握概念本质建构生态课堂—对初中数学概念课教学的几点思考

数学概念是人类对现实世界的空间形式和数量关系的简明概括及反映,它是数学学科的精髓、灵魂.数学概念是进行推理、判断、证明的依据,是建立定理、法则、公式的基础,也是形成数学思想方法的出发点.因此,概念教学在数学教学中有着重要的地位和作用.对数学概念的教学,其"生态课堂"的建构一定要以学生已有的认知基础为出发点,去创设能让学生经历概念的发生、发展过程的教学情境.本文从学生认知基础的角度出发,就概念教学中的课堂建构作简单讨论.     

数学建模实验教学中的研究型教学设计原则与实例

综合在数学建模实验课程教学研究与相关教学实践中的一点体会,提出了对研究型教学进行实验设计的一些原则.通过具体的实例表明应用效果显著.     

中学生数学反思能力的培养

在提倡教师通过教学反思不断提高自己教育教学水平,努力成为一个研究型学者的今天,教师作为反思的主体,通过教学反思,使自身得到了提高.那么,作为学习主体的学生是否也应该积极反思,成为反思型学习者呢?笔者曾被这样的问题困扰过:这个问题我在课堂上强调过N次了,可还是有不少学生出错,或者听学生诉苦:"老师,你课堂上讲的我都听懂了,作业也会做,怎么考试时就不会了呢?"这从某种程度上反映了学生在学习过程中缺乏反思,原因可能是:(1)学生没有反思意识或不知道如何反思,以致很多学生到了高中甚至大学也没有找到适合自己的学习方法;(2)过重的学习负担,使学生没有时间反思;(3)教师在教学中只注重知识的传授与讲解,忽视了学生反     

Bound and collapse Bayesian reject inference for credit scoring

Reject inference is a method for inferring how a rejected credit applicant would have behaved had credit been granted. Credit-quality data on rejected applicants are usually missing not at random (MNAR). In order to infer credit-quality data MNAR, we propose a flexible method to generate the probability of missingness within a model-based bound and collapse Bayesian technique. We tested the method's performance relative to traditional reject-inference methods using real data. Results show that our method improves the classification power of credit scoring models under MNAR conditions.     

Dynamic analysis of a micro-resonator driven by electrostatic combs

The dynamic response of a micro-resonator driven by electrostatic combs is investigated in this work. The micro-resonator is assumed to consist of eight flexible beams and three rigid bodies. The nonlinear partial differential equations that govern the motions of the flexible beams are obtained, as well as their boundary and matching conditions. The natural matching conditions for the flexible beams are the governing equations for the rigid bodies. The undamped natural frequencies and mode shapes of the linearized model of the micro-resonator are determined, and the orthogonality relation of the undamped global mode shapes is established. The modified Newton iterative method is used to simultaneously solve for the frequency equation and identify repeated natural frequencies that can occur in the micro-resonator and their multiplicities. The Gram-Schmidt orthogonalization method is extended to orthogonalize the mode shapes of the continuous system corresponding to the repeated natural frequencies. The undamped global mode shapes are used to spatially discretize the nonlinear partial differential equations of the micro-resonator. The simulation results show that the geometric nonlinearities of the flexible beams can have a significant effect on the dynamic response of the micro-resonator.     

Global mode method for dynamic modeling of a flexible-link flexible-joint manipulator with tip mass

In this paper, the global mode method (GMM) is proposed to obtain a reduced-order analytical dynamic model for a signal flexible-link flexible-joint (SFF) manipulator. Firstly, the nonlinear partial differential equations (PDE) that govern the motion of the flexible link and flexible joint, respectively, are derived by applying the Hamilton principle. By combining the linearized governing equations of motion for a flexible link and the equation of motion for the flexible joint, the characteristic equation is obtained for the whole system. The natural frequencies and global mode shapes of the linearized model of the SFF manipulator are determined, and orthogonality relations of the global mode shapes are established. Then, the global mode shapes and their orthogonality relations are used to truncate the nonlinear PDEs of the SFF manipulator to a nonlinear ordinary differential equation with a few degrees-of-freedom (DOF). For comparison, two other dynamic models of the SFF are derived by employing the assumed mode method (AMM) and finite element method (FEM). To verify the method proposed, the results from the GMM are compared with those obtained from the FEM. The effects of the link length and payload mass on the convergence of AMM model for the first two frequencies are investigated. Based on the dynamic models, obtained by GMM and AMM, dynamical responses for the system with different numbers of modes are worked out numerically, which are compared with those obtained from FEM. These comparisons show a good agreement between the results of the GMM and that of the FEM model, which indeed proved the accuracy and applicability of the GMM model.     

基于组合智能控制的柔性臂微机控制系统研究

针对难以控制的柔性机械臂，设计了强鲁棒性、强自适应能力的模糊滑模控制策略；并针对控制对象与控制算法的复杂性，设计了基于DSP＋FPGA的控制系统，保证了系统的实时性和精确度。     

Sliding mode control experiments of uncertain dynamical systems with time delay

This article presents the simulation and experimental studies for the nonlinear time-delayed dynamical systems with uncertainties. A rotary flexible joint made by Quanser is chosen as the model system to investigate the method for sliding mode control design. We considered the geometric nonlinearity of the flexible joint consisting of two linear springs. The system is assumed to have constant delay time and uncertain parameters with known upper and lower bounds. We also design an optimal sliding surface for the sliding mode control. Simulations and experiments are carried out to demonstrate the utility of the control method. Finally, the results from the simulations and experiments are in excellent agreement.     

Adaptive credit scoring with kernel learning methods

Credit scoring is a method of modelling potential risk of credit applications. Traditionally, logistic regression and discriminant analysis are the most widely used approaches to create scoring models in the industry. However, these methods are associated with quite a few limitations, such as being instable with high-dimensional data and small sample size, intensive variable selection effort and incapability of efficiently handling non-linear features. Most importantly, based on these algorithms, it is difficult to automate the modelling process and when population changes occur, the static models usually fail to adapt and may need to be rebuilt from scratch. In the last few years, the kernel learning approach has been investigated to solve these problems. However, the existing applications of this type of methods (in particular the SVM) in credit scoring have all focused on the batch model and did not address the important problem of how to update the scoring model on-line. This paper presents a novel and practical adaptive scoring system based on an incremental kernel method. With this approach, the scoring model is adjusted according to an on-line update procedure that can always converge to the optimal solution without information loss or running into numerical difficulties. Non-linear features in the data are automatically included in the model through a kernel transformation. This approach does not require any variable reduction effort and is also robust for scoring data with a large number of attributes and highly unbalanced class distributions. Moreover, a new potential kernel function is introduced to further improve the predictive performance of the scoring model and a kernel attribute ranking technique is used that adds transparency in the final model. Experimental studies using real world data sets have demonstrated the effectiveness of the proposed method.     

电力系统多目标优化运营研究

针对智能电网系统的安全与经济运行问题,建立了一个同时考虑经济、环境和安全指标的电网系统多目标优化模型,并运用理想点法对电网系统的多目标优化运营问题进行了相应的决策性分析,然后使用了一种新型的智能计算方法——标杆管理优化算法对该模型进行了求解计算.仿真实例表明,本文提出的决策分析和求解计算方法是切实可行的,具有一定的实用性和灵活性.此外,在计算过程中对一些相关的技术性问题,如对协调模型中的两类不同的控制变量、基因链的构造、约束条件的处理以及目标函数的选取等问题做了一些研究和探讨.     

Modelling of dynamic interaction between structure and trolley for mega container cranes

This article deals with the analysis of trolley impact on the dynamic behaviour of the flexible structure of the mega quayside container crane (QCC) boom, identified as the most relevant structural part. It develops a modelling method for the dynamic response of the large flexible structure of the QCC boom under a moving trolley. By using FEM the original structure of the whole crane structure is reduced to an equivalent model of the boom. The boom is in this way modelled as a system with distributed parameters, comprising reduced stiffnesses and lumped masses from other parts of the upper structure. The article looks at the moving mass approach to achieve the desired performance of the QCC. Differential equations of the mathematical model are obtained by using Lagrange's equations and the assumed mode method. The continuum is discretized by a finite number of admissible functions. Deterministic simulation gives the dynamic response of the boom for quay-to-ship container transfer. Results are obtained for the boom deflection and bending moment values, as well as for the dynamic amplification factor of deflection.     

固定经营期下基于运行绩效的PPP项目服务价格形成机制研究

本文研究PPP项目价格形成机制、补偿机制及其社会效率。首先,分析了招投标制度下固定经营期PPP项目服务价格形成机制及其不足。其次,基于成本与运行绩效的PPP项目定价规制及可行性缺口补贴思想,建立模型分析实施机构可观察PPP项目服务成本时的定价水平和可行性缺口补贴标准;当实施机构无法准确掌握项目公司的运行成本时,通过制度设计诱导社会投资者上报真实的运行成本和运行绩效以获得最大净现值。分析表明,当PPP项目服务需求弹性较大同时有可行性缺口补贴政策时,政府进行价格规制时项目净现值高于不规制时的净现值。文章通过实例验证了成本信息是否可观察两种情形下PPP项目的服务价格水平、运行绩效、项目投资净现值及消费者剩余。为了避免PPP项目运行绩效下降和社会福利损失,政府应建立科学的监督激励机制,依据PPP项目服务成本与运行绩效的信息确定固定特许经营期下项目服务价格和可行性缺口补贴额度。     

柔性约束下压杆的一些稳定和不稳定的临界状态

研究了一端固定、一端弹簧约束滑动固定的压杆在Euler临界载荷作用下的稳定性.将系统的势能表示为转角的泛函,将扰动量展开成Fourier级数,将势能的二阶变分表示成一个二次型,得到在临界状态下势能的二阶变分半正定,并求得临界载荷与屈曲模态.进一步研究临界状态下高阶变分的正定性,包括四阶和六阶变分的正定性.结果表明,与刚性约束不同的是,柔性约束压杆临界状态的稳定性与约束的刚度有关,有稳定与不稳定之分,并给出了临界状态是稳定和不稳定的情况下柔性约束相对刚度的范围.