扇形区域外问题的自适应边界元方法

本文研究扇形区域外laplace问题的自适应自然边界元方法.我们充分利用了自然积分算子的特殊性质和积分核级数展开法,得到了两个新的可靠后验误差估计.数值算例验证了理论分析结果.     

非线性离散系统的近似最优跟踪控制

研究非线性离散系统的最优跟踪控制问题. 通过在由最优控制问题所导致的非线性两点边值问题中引入灵敏度参数, 并对它进行Maclaurin级数展开, 将原最优跟踪控制问题转化为一族非齐次线性两点边值问题. 得到的最优跟踪控制由解析的前馈反馈项和级数形式的补偿项组成. 解析的前馈反馈项可以由求解一个Riccati差分方程和一个矩阵差分方程得到. 级数补偿项可以由一个求解伴随向量的迭代算法近似求得. 以连续槽式反应器为例进行仿真验证了该方法的有效性．     

空间杆系结构回传波射分析及程序实现

为有效地进行杆系结构应力波响应分析,基于传统的空间杆系结构回传波射矩阵法,考虑黏滞阻尼、复刚度阻尼及节点集中质量的影响,采用VC+ +编制通用回传波射矩阵法分析程序. 该程序可以计算空间杆系结构在任意动力集中载荷作用下任意位置的动力瞬态响应. 针对某刚架结构,比较运用该程序与运用有限元法得到的结果,验证该方法的精确度.     

热工对象的低阶近似模拟

本文针对热工对象一般阻尼较大的特点,根据由级数展开取得低阶近似公式的原理,得到了统一而又便利的数学简化方法;用在单回路调节系统的模拟和分析中,可以得到相当准确的结果.文中以多容对象、单相换热器和纯时滞环节等典型对象为例,求得了一系列的低阶近似式和图表,并验证了它们的准确性.文中又以锅炉的某一个单相区的各类实际传递函数为例,求出了低阶近似式,论证了复杂环节同样可以低阶简化.文中还讨论了如何由对象的实验飞升曲线求其低阶近似传递函数,指出文献[1]的积分法实质上就是级数展开法,并对其计算程序作了一些改进.     

平面二级倒立摆的圆周行走与镇定控制

采用拉格朗日方程建立了平面二级倒立摆的非线性动力学模型, 将其在平衡位置线性化, 得到系统在两个正交控制方向解耦的近似模型. 针对每一个方向上由互相耦合的基座小车定位子系统和摆杆镇定子系统所组成的六阶欠驱动系统, 设计了自适应滑模模糊控制器, 实现了基座小车沿圆周行走条件下摆杆的镇定控制, 验证了该控制算法对欠驱动、不稳定、多变量耦合系统的有效性.     

五杆五环结构机床的运动学建模和分析

本文介绍了一种用于高速加工的五杆五环新型并联机床,分析其运动形式。在建立了五杆五环并联机床三维模型的基础上,首次运用齐次坐标变换方法推导了其逆向运动学模型,得到各杆长与刀尖点位置和姿态的关系。最后,针对主轴的典型位置和姿态点对所建立的运动学模型进行验证,证明运动学模型的准确性。     

一种基于BP-GA的室内定位模型

使用BP-GA算法相结合的方法来作为室内定位模型的主要定位算法,在得到初始坐标后利用泰勒级数定位算法优化得到最终待测点坐标。该算法很好地减弱了室内环境对定位精度的影响,并且具有较高的精度。仿真实验验证了该模型的有效性。     

基于流场与劳伦级数的指纹奇异点检测算法

提出一种基于流场与劳伦级数的指纹奇异点检测算法.运用指纹标量场的梯度信息得到指纹流场,在指纹流场与劳伦多项式之间互相关性的基础上,采用多尺度复数滤波的互相关性能量检测指纹奇异点.在SPD2010指纹数据库上进行实验研究,结果验证该算法能够实现指纹流场中奇异点的旋转不变性检测,检测效果优于SPD2010中的最优算法.     

带阶跃扰动的线性时滞系统最优无静差控制

研究线性时滞系统在阶跃扰动作用下的最优控制问题．首先基于内模原理构造扰动补偿器,以完全消除阶跃扰动对系统的影响。并将原系统的最优无静差扰动抑制问题转化为无扰动最优控制问题;然后利用灵敏度方法,求得由精确的解析项和伴随向量级数形式补偿项组成的最优控制律,通过截取伴随向量级数的有限项和．可得到次优无静差控制律．仿真实例验证了该方法的有效性．     

用dBASE Ⅲ打印杨辉三角

华罗庚先生生前写过一本书—《从杨辉三角谈起》,由此得出了一系列重要结论,开方、高阶等差级数、差分多项式、逐差法、堆垛术、混合级数、无穷级数、无穷混合级数、循环级数、斐波那契级数、倒数级数、级数sum from n=1 to ∞(1/n~2)的渐近值等等,足见杨辉三角之重要.另外,在概率统计中计算C_n~k二项分布的极限有两个,一是poisson分布,一是正态分布.因此,用计算机打印出杨辉三角,在实践中有着广泛的应用.     

Transient electroosmotic slip flow of fractional Oldroyd-B fluids

The electroosmotic flow of a fractional Oldroyd-B fluid in a circular microchannel is studied. The linear Navier slip velocity model is used as the chosen slip boundary condition. Exact solutions for the electric potential and transient velocity are established by means of Laplace and finite Hankel transforms. And the velocity was presented as a sum of the steady part and the unsteady one. The corresponding solutions for the fractional Maxwell fluid, fractional second grade fluid, and Newtonian fluid can also be obtained from our results. Finally, numerical results for the fluid flow are obtained and some useful conclusions are drawn. Our results may be useful for the prediction of the flow behavior of viscoelastic fluids in microchannels and can benefit the design of microfluidic devices.     

Pattern Recognition Applied to Measurement of Human Limb Positions during Movement

Abstract

A set of computer programs has been written which read a code and measure the positions of certain marks in a sequence of pictures (film strip). In the present application dots mark definite spots on the limbs and the torso and a code identifies the location where the frame was taken. By processing a sequence of consecutive frames, the trajectories of points on limbs are obtained from which velocity, acceleration, various angles, potential and kinetic energy etc. are computable. The same film can also be shown as a movie for visual evaluation and identification. Results are presented for the case of a rotating disc marked with three spots and for a subject performing a stationary walk.

The system is of value in expediting the processing of basic data in studies upon human locomotion and for the design and development of prosthetic devices. It is proposed to correlate recordings obtained with myo-electric signals generated by the lower limb musculature.     

基于广播星历的卫星速度和加速度实时计算方法

针对当前利用精密星历不能实现卫星速度和加速度实时获取,进而影响移动载体速度和加速度解算的时效性问题,提出一种基于广播星历实时计算卫星速度和加速度方法.分析现有广播星历求取卫星速度方案存在的局限性,推导基于矩阵形式的卫星运动速度求解公式,通过实测数据分别对广播星历和精密星历计算的卫星速度和加速度结果进行对比分析,结果表明:广播星历计算卫星位置误差在2 m以内,速度误差优于1.4 mm/s,加速度误差优于0.05 mm/s2,且具有良好的实时性.     

低液位非满管流量校准及其测量影响因素分析

管道粗糙度和流体黏度对流量测量有一定影响,为校准流量并分析其影响因素,运用FLUENT仿真软件对管道粗糙度、流体黏度进行模拟.建立粗糙度-平均流速、黏度-平均流速模型,搭建实验平台,验证模型建立的准确性,即外置U形连通管结合高精度激光测距仪精确测量管道内流体液位高度,管道上方通气管结合流速仪精确测量管道内流体平均流速,...     

Operational domain theory and topology of sequential programming languages

A number of authors have exported domain-theoretic techniques from denotational semantics to the operational study of contextual equivalence and order. We further develop this, and, moreover, we additionally export topological techniques. In particular, we work with an operational notion of compact set and show that total programs with values on certain types are uniformly continuous on compact sets of total elements. We apply this and other conclusions to prove the correctness of non-trivial programs that manipulate infinite data. What is interesting is that the development applies to sequential programming languages, in addition to languages with parallel features.     

Programming by discovery

Abstract The concept of Programming by Discovery refers to the process of designing programming environments and systems which use various visualisation, programming and interaction technologies in an effective way to help users, especially beginner programmers, in writing computer programs, understanding their dynamic behaviour, detecting any misconceptions and bugs associated with them, and seeing the effect of these programs on the underlying machine. A system for programming by discovery encourages a user to become an active learner by allowing him to form his own hypotheses, explore his own questions, and draw his own conclusions. This paper reports on the design and evaluation of a system for programming by discovery which embodies the principles outlined above. To assess the usefulness of the design framework presented in this paper, a pilot empirical evaluation was conducted. The results provided a number of interesting insights into the implication of incorporating visualisation and immediacy features along with graphical notional machine and algorithm-like language into the design of programming systems.     

Energy program validation: conclusions of IEA Annex I

Computer programs for predicting the energy consumption of a building are providing architects and building services engineers with very valuable aids to assist them in the design function. The calculation of building energy flows is extremely complex, and so validation is a vital element in the development of any model. Under the auspices of the International Energy Agency, 23 computer program owners from 8 different countries collaborated in a joint R&D project to compare energy programs, both in terms of consistency between programs, and in considering the accuracy of these same programs in modelling the behaviour of a real building. This paper summarizes the major conclusions that developed out of the project, and gives insight into some of the most important aspects which need to be considered in the development of a reliable computer program.     

基于CFD的通信机房流场模型建立与分析

介绍了一种利用计算流体动力学技术分析通信机房流场分布的方法,找出合理的气流组织形式以达到节能的目的.对机房三维物理模型进行非结构化网格划分,选用标准的k-ε湍流模型,设定相应的边界条件,针对不同的空调风速工况,利用Fluent软件对机房内的温度场和速度场进行数值模拟与分析,研究得出合理的风速以降低能耗.该方法能够有效地建立通信机房的流场模型,对制定机房节能方案有重要的参考作用.     

Numerical computation of the linear convective and absolute stability of free-shear flows

The linear stability of free-shear flows is governed by their dispersion characteristics. The dispersion relation can be obtained by integrating the Rayleigh equation. The integration process can be hampered by the presence of singularities within the domain of integration. A complex-domain contour integration procedure is presented that enables this integration to be performed in a modular and robust fashion. This is accomplished by deforming the original integration contour into piecewise-continuous line-segments in the complex domain to avoid all the singularities. This integration technique can then be used to find absolute and convective instabilities of the medium by a simple procedure. However when the velocity profile for a shear layer is obtained from experiments or numerical simulations, it is available only along the real-axis. Thus the complex-domain integration procedure cannot be applied unless a functional fit is obtained for the velocity profile. For convectively unstable systems, the integration can be carried out along the real-axis only for self-excited systems. However, for a certain class of free-shear flows, it is shown that an absolute instability can still be calculated by integrating the Rayleigh equation along the real-axis. This leads to the development of a fully automatic absolute-instability solver and a semi-automatic convective-instability solver.     

单波束声学多普勒流速仪垂向在线测流应用研究

通过应用单波束垂向式声学多普勒流速仪(V-ADCP)进行在线流量测验,探索单波速V-ADCP的安装和流速数据处理计算方法。采用转子式流速仪对V-ADCP进行比测,分析V-ADCP采用相对水深某个区间范围内的单元流速计算垂线平均流速的方法,率定符合水文相关规范的V-ADCP测流的单断速关系,并确定单断速关系可生产应用的范围。通过对V-ADCP在线测流的应用,得到精度较高的单断关系,实现流量在线监测,可为进一步推广V-ADCP在线测流的应用进行探索。