微分方程教学中的若干注记

通过微分方程教学中的两个例题,提出解这两类微分方程时,学生容易产生困惑的几个问题,并在分析问题产生原因的基础上,对所提出问题进行了解答,最后,给出了可变量分离方程和一阶线性微分方程教学的几点注记。     

Dog Treat Ball: An Activity to Introduce Systems of Differential Equations

Abstract

This paper describes an activity using a dog treat ball to introduce systems of first-order differential equations. Beads are placed in the first of two hemispherical chambers of a food-dispensing dog toy. As the ball is turned, students track the number of beads in the first chamber, the second chamber, and the exterior of the ball. Students develop a working assumption, write a system of differential equations to model the number of beads in each region, and use a spreadsheet to compare their experimental and model results.     

Pharmacokinetic Models for Active Learning of Differential Equations

Abstract

We present adaptable activities for models of drug movement in the human body – pharmacokinetics – that motivate the learning of ordinary differential equations with an interdisciplinary topic. Specifically, we model aspirin, caffeine, and digoxin. We discuss the pedagogy of guiding students to understand, develop, and analyze models, progressing in complexity to a system of differential equations. We investigate the effects of parameter values that distinguish various health levels, and dosing that may have toxic effects. Our assignments include modeling in a student-centered, active, and increasingly inquiry-oriented setting through which the mathematics and biology inform and reinforce each other. We include supplemental information regarding inquiry methods, student learning outcomes, a student’s commentary about our activities, and support through mathematical communities such as POGIL and SIMIODE.     

常微分方程课程中的线性微分方程组的解的存在唯一性定理的教学改革探讨

以建构主义的学习理论为基础 ,结合学习的实际情况和已有的经验背景 ,创建合适的学习情境 ,对常微分方程课程中的线性微分方程组的解的存在唯一性定理的教学过程进行了改革 ,具体做法是 ,减少讲授时数 ,将讲课时间控制在10min之内 ,而将大部分时间用于学习自己练习以及学习之间、学生与教师之间的交流的探讨 ,使学生能够综合贯通 ,形成完整的知识结构。     

Mathematica在常微分方程实验中的应用

通过实验阐述用Mathematica求解各类常微分方程的输入格式和应注意的问题,使常微分方程的解法更直观、简便和高效,充分说明用Mathematica进行数学实验,有利于激发学生学习数学的兴趣,培养学生建立数学模型、使用计算机解决实际问题的能力.     

Using Harvesting Models to Teach Modeling with Differential Equations

Abstract: Harvesting models based on ordinary differential equations are commonly used in the fishery industry and wildlife management to model the evolution of a population depleted by harvest mortality. We present a project consisting of a series of scenarios based on fishery harvesting models to teach the application of theoretical concepts learned in a differential equations course to scenarios encountered in real fisheries. These projects require a thorough understanding of simplifying assumptions inherent in various models, as well as a qualitative analysis of phase portraits, bifurcations, and stability of steady states. Parameters are estimated and equations are sometimes solved both analytically and numerically. Students learn to respond to a professional request from a fishery in the form of a scientific report, which requires organizing and communicating assumptions, models, solution methods, results, and a final recommendation with clarity and professionalism.     

偏微分方程教学改革与探索

偏微分方程是数学专业一门重要的专业基础课,本文主要针对偏微分方程课时少、内容多而且难的特点,进行了教学内容上的调整和教学手段上的改进,期望能够提高学生学习的积极性和主动性。     

Discovering the Power of Individual-Based Modelling in Teaching and Learning: The Study of a Predator–Prey System

The general aim is to promote the use of individual-based models (biological agent-based models) in teaching and learning contexts in life sciences and to make their progressive incorporation into academic curricula easier, complementing other existing modelling strategies more frequently used in the classroom. Modelling activities for the study of a predator–prey system for a mathematics classroom in the first year of an undergraduate program in biosystems engineering have been designed and implemented. These activities were designed to put two modelling approaches side by side, an individual-based model and a set of ordinary differential equations. In order to organize and display this, a system with wolves and sheep in a confined domain was considered and studied. With the teaching material elaborated and a computer to perform the numerical resolutions involved and the corresponding individual-based simulations, the students answered questions and completed exercises to achieve the learning goals set. Students’ responses regarding the modelling of biological systems and these two distinct methodologies applied to the study of a predator–prey system were collected via questionnaires, open-ended queries and face-to-face dialogues. Taking into account the positive responses of the students when they were doing these activities, it was clear that using a discrete individual-based model to deal with a predator–prey system jointly with a set of ordinary differential equations enriches the understanding of the modelling process, adds new insights and opens novel perspectives of what can be done with computational models versus other models. The complementary views given by the two modelling approaches were very well assessed by students.     

Didactising: Continuing the work of Leen Streefland

In this paper we present three cases of instructional design that illustrates both horizontal didactising, the activity of using already established principles to design instruction, and vertical didactising the activity of developing new tools and principles for instructional design. The first case illustrates horizontal didactising by elaborating how the constructs chains of signification and models were used to design an instructional sequence involving linear growth. The second and third cases illustrate vertical didactising by developing argumentation analyses and generative listening, respectively, as instructional design tools. In the second case, argumentation analyses emerge as a tool that other designers can use to anticipate the quality of conversations that can occur as students engage in tasks prior to implementing the instructional sequence. The third case develops the notion of generative listening as a conceptual tool within the context of designing differential equations instruction to gain insights into what are, for students, experientially-real starting points that are mathematical in nature and to provide inspirations for revisions to instructional sequences. This revised version was published online in August 2006 with corrections to the Cover Date.     

Using the United States Census Data to Introduce Differential Equations

Abstract

This article describes a method for using the United States Census data to open a differential equations course. The question of finding a model for the United States population data gives students a first experience with creating a model using differential equations, and also understanding derivatives, what they mean, and how to calculate them in the context of real data. This model-building start motivates further exploration in many of the standard differential equations topics: the method of separation of variables, slope fields, autonomous equations, equilibria, and stability.     

连续状态方程的计算机数值求解方法比较

讨论了三种连续状态方程的计算机数值求解方法，并比较了各种方法的性能．“离散状态方程法”与Ｅｕｌｅｒ法计算量相当，较Ｒｕｎｇｅ－Ｋｕｔｔａ法计算量要小．当输入信号变化较慢时，“离散状态方程法”具有较高的计算精度，远高于Ｅｕｌｅｒ法计算精度．特别地，当输入信号为阶跃信号或求方程齐次解时，该方法计算精度比其它任何一种数值算法都高     

求解二阶常系数线性微分方程的若干方法

在科学研究、工程技术中,常常需要将某些实际问题转化为二阶常微分方程问题,因此研究不同类型的二阶常微分方程的求解方法具有十分重要的意义。介绍二阶常系数线性方程的若干种求解方法,包括多项式法、升阶法、积分法、微分算子法等等。这为我们今后进一步研究常微分方程提供了基础。     

混合效应随机微分方程的贝叶斯分析(英文)

采用带有随机微分方程的非线性混合效应模型对群体药物代谢动力学数据建模,通过在状态方程中引入随机项,将常微分方程扩展到随机微分方程.和常微分方程相比,随机微分方程可解决群体药物代谢动力学模型中相关残差问题.利用贝叶斯估计对非线性混合效应随机微分方程模型参数进行估计,给出群体参数及个体参数的精确后验分布,将Gibbs和Metropolis-Hastings算法相结合,给出参数估计值.通过计算机模拟和实例分析验证了方法的可靠性,结果表明利用非线性混合效应随机微分方程模型及贝叶斯估计方法分析群体药物代谢动力学数据是可行的.     

基于P．Perona和J．Malik方程的图像放大

偏微分方程在图像去噪、重建等图像处理领域中都已经有了较多较好的应用,基于一种全新的图像放大方法,即基于偏微分方程的图像放大法,该方法主要是利用热传导原理,建立热传导过程的数学模型,实现图像放大的目的．提出了一种基于P．Perona和J．Malik方程的图像放大的算法．数值离散采用直观的有限差分格式,实验在Matlab环境下进行．实验结果表明该法在放大过程中保持了图像的特征,也说明了该算法实现图像放大的有效性．     

常微分方程在数学建模中的应用

随着应用微分方程的解法和理论的日臻完善,人们越来越关注用该理论建立数学模型解决实际问题。本文介绍了利用常微分方程理论建立生物种群数量模型、腐败分子人数预测模型的建立过程。     

四阶线性微分方程组的离散谱估计

考虑四阶线性微分方程组的离散谱估计,利用矩阵运算,分部积分和不等式估计等方法与技巧,得到了用前n个特征值来估计第n 1个特征值的上界的不等式,其估计系数与区间的几何度量无关,其结果在物理和力学等领域有着广泛的应用。     

常微分方程在数学建模中的应用

文章深入探究了常微分方程在数学建模中的应用,阐述了常微分方程的发展和数学建模,并结合二者的特点与相关常微分方程在数学建模的例子,总结出常微分方程在数学建模的如何应用及学习过程中应注意的事项。     

浅谈常微分方程教学中的若干问题

常微分方程是一门很重要的基础专业课,本文作者在主持内蒙古自治区精品课常微分方程和内蒙古大学微分方程系列课程教学团队期间,结合多年的常微分方程教学经验,对于常微分方程课的教学方法和教学手段进行了一些粗浅的探索和研究,依据“讲背景、讲思想、讲方法”的教学理念,增强教学的趣味性,激发学习的主动性,取得了良好的教学效果。     

求解瞬态Naiver-Stokes问题的一种稳定化方法

在压力投影及多尺度变分法的基础上,本文针对瞬态Naiver-Stokes问题提出一种新的稳定化方法,此方法采用非协调且不满足inf-sup条件的速度及压力有限元空间。文中的稳定化方法具备一些优势:能避免高阶微分的计算,数据结构与单元边界无关;只在好的尺度上增加离散的速度项,对高雷诺数的流体很有效;不增加计算成本。