饮酒驾车

针对酒后驾车问题,根据微分方程理论以及合理的假设,建立了体液中酒精含量随时间变化的数学模型,并求得其特解.再根据给定的数据,运用MATLAB软件确定回归方程的系数.由此,对于不同的喝酒方式以及喝下的不同数量的酒,进行血液中酒精浓度的分析,可以预测喝酒后任意时刻血液中的酒精浓度,并能预测不同喝酒方式以及喝下的不同数量的酒后能否驾车的时间分界点.从而对问题作出科学的解释和证明.     

基于社会敏感问题的问卷调查方案设计与分析

利用概率论与数理统计方法,以对酒后驾车现象为例,就社会敏感问题的问卷调查方案设计,建立数学模型,并对模型结果进行分析.     

酒后驾车问题的数学模型

就酒后驾车问题,仿照药物动力学原理,考虑吸收系统和迟滞时间,建立了二房室模型,得出了饮酒者饮酒后血液中的酒精含量与饮酒量、饮酒方式及时间的关系.根据提供的测量数据,通过多种方法计算模型参数,选用了总体残差平方和最小的阻尼最小二乘法的计算结果作为模型参数.最后对相关问题进行了解答,结果表明,模型是合理和有效的.     

道路也有奇偶性吗——武汉七桥一线游的答疑

[故事]这天,一位游客与出租车司机发生了争执,把官司打到了九头鸟数学茶楼. 司机:你提出的"武汉七桥一线游,不走桥上重复路"的要求是做不到的! 游客:怎么做不到?我的朋友说,他曾自己驾车七桥观光不走重路!     

饮酒驾车模型的进一步研究

通过分析啤酒中的酒精在人体内胃肠(含肝脏)和体液中的交换机理,建立了在"天天喝酒且是较长时间内喝下"时的酒精在人体内的积累函数,利用该函数推导出了在喝酒数量和喝酒时间确定的情况下,司机驾车不会违章的时刻表,最后画出了在一个周期内酒精积累函数的变化趋势图,分析了该酒精积累函数的单调性和最大值.     

道路行车系统中人的可靠性研究

随着人-车-路-环境系统复杂性的增加和交通事故数量的上升,新型交通设备对其使用者的素质与适应性提出了全面的要求,要提高道路行车系统的整体可靠性,必须对人的可靠性进行分析研究.从人的生理、心理、教育训练、驾车技能等因素对驾驶员可靠性的相关影响进行了探讨.分析了影响驾驶员的可靠性因素,研究了驾驶员的可靠性模型,提出建立有助于驾驶员可靠性分析研究的综合数据库,最后从理论上分析总结了提高驾驶员可靠性的措施从而得出提高道路行车安全的有效途径.     

血液中酒精浓度的数学模型

把人体对酒精的吸收、排放简化为一般的房室模型,提出了吸收因子、消除因子的概念.针对短时间饮酒、长时间饮酒以及间断饮酒等情况,分别建立了关于人体体液中酒精浓度的微分方程模型,并且给出了显式解.对于特殊的周期性间断饮酒的模型,给出了更便于计算的叠加公式,并通过分析酒精浓度函数的极限过程,证明了其有界性.对短时间饮酒和长时间饮酒的情况分别计算了酒精浓度的最大值、取得最大值的时间和禁止驾车的时间范围,而且进行了比较,所得结论与实际吻合.     

基于后悔理论的拼车决策问题研究

本文针对瓶颈路段,研究了出行者在单独驾车和拼车这两种出行模式下的早高峰出行行为。首先根据瓶颈模型的均衡条件,分别推导了收费和不收费机制下单独出行和拼车出行的出行时间及广义出行成本。为进一步研究出行者的出行方式选择,本文建立了基于后悔理论的随机Logit模型,并提出了相应的迭代平均算法。研究表明,在不收费机制下单独驾车和拼车出行者混合出发,而最优收费机制则实现了交通流的分离,其中拼车出行者在瓶颈的高峰时段出行而单独驾车者在瓶颈的颈部出行。算例结果表明,后悔厌恶水平是影响出行者出行方式选择行为的重要参数,其中,选择最低成本的出行者随着后悔厌恶水平的增加而增加。     

奇怪的柿子

一、特别的奶牛车 昨天是周末,我回到家本打算饱饱地睡一个懒觉.可是,一大早却被爸爸的大嗓门吵醒了. 我一睁开眼睛,就看到爸爸的大脸,他俯身望着我:“乖儿子,难得你回来一趟,今天爸爸带你去自驾游,怎样?” “自驾游是什么东西?”我不明白. “你看你,成天在孔老师那边学习,连现在最流行的自驾游都不懂.”爸爸解释说,“自驾游就是咱们自己驾车出游,也就是自助旅游.”     

一类利用速度比求最值问题

张奠宙、戴再平两位先生所编的《初中数学应用问题》中有这样一道例题:一条笔直的公路l穿过草原,公路边有一卫生站A,距离公路30千米的地方有一居民点B,A,B的直线距离是90千米.有一天,某司机驾车从卫生站送一批急救药品到居民点B,汽车在公路上     

Time-linearized,compact methods for the inviscid GRLW equation subject to initial Gaussian conditions

The objective of this paper is three-fold. First, four time-linearization methods that are second- and fourth-order accurate in time and space, respectively, are presented and used to study the dynamics of the modified and generalized regularized-long wave equations (mRLW and GRLW equations, respectively). Two of the methods use the conservation-law form of the equations and treat the wave amplitude and its second-order spatial derivative and the linear and nonlinear advection fluxes as unknowns, whereas the other two employ the non-conservation-law form of the equations and consider the wave amplitude and its first- and second-order spatial derivatives as unknowns. The methods employ three-point fourth-order accurate Padé discretizations for the first- and second-order derivatives, are second-order accurate in time, and yield linear systems of blocktridiagonal matrices. Second, the accuracy of these methods is assessed by comparing their results with those of the exact solution of the mRLW equation. It is reported that the four methods predict nearly the same values of the three invariants and have the same accuracy, and that an accurate prediction of the invariants may not correspond to small errors in space and time. Third, the dynamics of the inviscid GRLW equation is studied first qualitatively in terms of length and time scales and then numerically as a function of the linear advection speed, the exponent of the nonlinear advection flux, the dispersion coefficient and the amplitude and width of the initial bell-shaped or Gaussian conditions. It is shown that wide initial conditions result in wave steepening and breakup and the formation of solitary waves whose amplitude and speed decrease as the time for their formation increases. For narrow initial conditions, it is shown that only a single solitary wave may form. Behind this wave and depending on the parameters that characterized the inviscid GRLW equation, rarefaction or negative amplitude waves that propagate towards the upstream boundary or a train of localized oscillatory waves that do not emerge from the trailing edge of the leading solitary wave may be formed. These oscillatory waves exhibit the characteristics of, but are not dispersive shock waves and their amplitude and frequency increases as the width of the initial conditions is decreased. The results presented here do not only complement previous work by the authors, they also show that the dynamics of the inviscid GRLW equation undergoes new and interesting phenomena as the width of the initial conditions is decreased.     

带有能源的随机动态柯布—道格拉斯生产函数

在考虑能源作为投入要素和经济环境随机动态变化的情况下,将经典的柯布-道格拉斯生产函数推广到随机动态的形式.首先给出了随机动态C-D生产函数的随机微分方程形式,证明了该生产函数解的存在性和唯一性;其次,进一步分析了解的Markov性质和扩散性质,并分别利用漂移系数和扩散系数给出了产出弹性的计算公式.最后,还给出了经济增长...     

行业结构环境的序参量分析方法研究

行业结构环境分析是发现和掌握行业运行规律与发展状况的必经之路,也是在企业战略管理中的重要组成部分,其结果直接影响着企业战略决策与实施。针对企业战略管理的新价值理念,本文在协同学与竞优理论的基础上,通过对行业内群体结构特性与企业行为的重新考察,建立了行业结构环境分析的一种新方法即序参量分析方法与其应用范例。本文的研究结果,如行业内多层结构、企业群组定位及分布特性、行业基本发展模式、标杆与协同伙伴、企业群组或群组内企业构成与绩效之间的关系等都可为实现符合现代产业发展环境的企业战略管理提供方向性辅助与技术支持。     

Boundary-Value Problems of the Theory of Thin and Nonthin Orthotropic Shells with Account of Nonlinearly Elastic Properties and Low Shear Rigidity of Composite Materials

The basic geometric and physical relations and resolving equations of the theory of thin and nonthin orthotropic composite shells with account of nonlinear properties and low shear rigidity of their materials are presented. They are derived based on two theories, namely the theory of anisotropic shells employing the Timoshenko or Kirchhoff-Love hypothesis and the nonlinear theory of elasticity and plasticity of anisotropic media in combination with the Lagrange variational principle. The procedure and algorithm for the numerical solution of nonlinear (linear) problems are based on the method of successive approximations, the difference-variational method, and the Lagrange multiplier method. Calculations of the stress-strain state for a spherical shell with a circular opening loaded with internal pressure are presented. The effect of transverse shear strains and physical nonlinearity of the material on the distribution of maximum deflections and circumferential stresses in the shell, obtained according to two variants of the shell theories, is studied. A comparison of the results of the problem solution in linear and nonlinear statements with and without account of the shell shear strains is given. The numerical data obtained for thin and nonthin (medium thick) composite shells are analyzed.     

一类KdV-Burgers方程的奇摄动解与孤子解

讨论了一类具有大Reynolds数且弱频散性的KdV-Burgers方程, 在数学上表示为一类奇摄动KdV-Burgers方程.KdV-Burgers方程中含有的非线性项与频散项互补作用形成稳定向前传播的孤立子.通过数学分析, 描述了孤立子的传播途径和传播速度等物理量的发展变化规律.通过奇摄动展开方法, 构造了该问题的渐近解.首先,用Riemann-Earnshaw方法求得退化解, 得到了简单波, 该简单波波形中的任意一点与初始点都存在一个传播速度差, 这使得波在传播过程中波形不断畸变, 最终形成冲击波面, 即间断面, 在它的两侧质点的速度有一个跳跃, 且随时间不断变化;其次, 在退化解的间断曲面处做变量替换, 构造一种修正的行波变换, 得到了内解展开式的孤子解, 并证明了内外解的存在性与唯一性;最后,通过一致有界逆算子的存在性做了余项估计, 并得到渐近解的一致有效性.结果表明, KdV-Burgers方程在大Reynolds数且弱频散性的性质下,扰动集中在退化解的间断面附近,孤立子链接两侧质点,其传播途径不是时间与空间的线性形式,而是沿着退化解的间断面附近传播,形成稳定的波形.     

Place and use of new technology in the teaching of mathematics: ICMI activities in the past 25 years

Looking back at the place of technology in the past ICMEs during the last decades and on the two ICMI studies devoted to technology, it is obvious that the role and use of technology has given rise to a diversity of points of view and attitudes across the world. The ICMEs and the two studies are places where researchers, teacher educators and practitioners meet. To what extent do they reflect the evolution of the trends of research and/or of integration of technology into real practice? The study will develop a general analysis of the theoretical frameworks, issues and wishes related to the use of technology in mathematics teaching from the proceedings of past ICMEs and of the two ICMI studies. Both a quantitative and a qualitative point of view will be adopted. From the great diversity of questions and approaches, the study attempts to formulate the main trends and their evolution over time within the ICMI community, as well as some pertinent issues for the coming years.     

一类人为错误可修复系统的指数稳定性分析

随着科学技术的发展,特别是电子产品和网络的运用,系统的可靠性分析变得日益重要.在Dhillon B S和Yang N F(1993)中通过增补变量的方法建立了这类系统的数学模型并进行研究.在此基础上进一步讨论系统解的渐进稳定性和指数稳定性,证明了系统算子在Bnacha空间中可以转化为C_0半群,0是系统算子的简单本征值,而且是系统在虚轴上唯一的谱点.此外本文还分析了在系统扰动前后系统算子解的基本谱,结果显示系统的动态解以指数稳定性趋向于系统的稳态解,通过maple作图发现系统稳定解有时候不一定趋向于系统的实际解,这对实际运用有重要的指导意义.     

The rank of a sequence as an indicator of chaos in discrete nonlinear dynamical systems

An alternative technique for clocking the convergence of iterative chaotic maps is proposed in this paper. It is based on the concept of the Hankel rank of a solution of the discrete nonlinear dynamical system. Computation and visualization of pseudoranks in the space of system’s parameters and initial conditions provides the insight into the fractal nature of the dynamical attractor and reveals the stable, the unstable manifold and the convergence properties of the system. All these manifolds are produced by a simple and a straightforward computational rule and are intertwined in one figure. On the other hand, the computation of ranks of subsequences of solutions helps to identify and assess the sensitivity of the system to initial conditions and can be used as a simple and effective numerical tool for qualitative investigation of discrete iterative maps.     

The rolling of a wheel along a corrugated rail

The rolling without detachment of a rigid massive wheel, carrying a static load, along a rail with undulations on the running surface, which arises as a result of non-uniform wear, is investigated. The rail is supported by an elastoviscous base. Because of the inertia of the wheel and the carriage the horizontal component of the velocity of the wheel centre differs only slightly from a constant quantity, and hence the motion of the wheel along the rail is assumed to be uniform. Steady vertical vibration of the wheel is considered. The vertical coordinate of the wheel centre, and also the difference between the longitudinal coordinates of the wheel centre and the point of contact of the wheel and the rail, are periodic and, correspondingly, even and odd functions of the longitudinal coordinate of the wheel centre, and their period is equal to the wave length on the rail surface. The periodic force of interaction of the wheel and the rail is given in the form of a Fourier series. Short waves, the amplitude of which is much less than their length, are often observed on the rail surface, and this length is much less than the wheel radius. In this case the coefficients of the Fourier series are expressed in terms of Bessel functions of the first kind of integer order. Observations show that the depth of the short wave on the rail surface increases until the radius of curvature in the rail trough approximates to the wheel radius, and hence it is assumed that these radii are close to or equal to one another. In this case the trajectory of the wheel centre differs considerably from the wave on the rail surface.     

基于“动态生成”的大学数学课堂教学

"动态生成"教学观的建立旨在摆脱课堂教学中以教师为中心、强调知识传授的传统教学模式的缺陷,从根本上正确理解课堂教学的复杂性和动态性,构建充满生命活力的大学数学课堂教学生态环境.在用动态生成的视角审视当前大学数学课堂教学中存在的问题的基础上,文章对在课堂教学中如何有效地进行动态生成提出了一些具体的策略:更新教学观念,精心预设弹性化的数学课堂教学方案;根据学生课堂反馈情况及时调整预设,并及时捕捉可利用的动态资源,为学生的生成创造可能的机会;加强教学研究,不断提高课堂教学智慧.