基于AutoLisp自动生成巷道线路坐标表

本文介绍AutoLisp语言,并采用该语言编制了巷道线路坐标表自动生成程序,该程序通过AutoCAD捕捉点功能提取坐标,自动对各点编号、计算坐标之间方位角和长度,能对圆弧段进行半径、弧长、切线长、角度的自动标注,能区分多条线路成表,并能自动生成坡度表.在实际工程中使用后,该程序能准确、迅速的生成坐标成果表和坡度表,节省了设计人员大量时间.

一种界址表和界址点坐标成果表的自动生成方法

界址表和界址点坐标成果表是地籍测绘资料制作过程中经常要绘制的表格,然而很多测绘单位没有专门的软件来绘制,在平时的作图中,都是手工操作,效率低下且容易出错。本文阐述了在AutoCAD平台下,如何应用VBA根据宗地图中界址点、界址线以及宗地的扩展属性自动生成界址表和界址点坐标成果表。程序已在Windows XP和AutoCAD 2004中运行通过。

Autolisp中的坐标变换及柱坐标的函数表

在参数建模中 ,应用Trans函数对不同坐标系中给定的点进行坐标变换 ,使Polar函数的参照点保持原来的空间位置。使用表处理函数和Polar函数连接 。

GPS坐标与公路桩号转换研究

在GIS和电子地图中,公路管理人员无法直接通过GPS经纬度坐标确定现场的公路桩号。为了实现对公路沿线工作点现场位置进行定位和标注,实现工作现场和公路管理系统软件上位置的相互对应。文章研究公路里程桩号与GPS经纬度坐标系统互换的方法,采用参考点GPS坐标数据采集和桩号对应法,建立参考点的桩号与参考点的GPS坐标对应表。通过桩号对应法和两次比例内插计算,然后取平均值的方法计算出实际工作点的两者相互关系,来实现公路桩号和GPS坐标相互转换功能。文章的转换计算过程采用合理的结构和实用的优化算法,缩短了计算时间,减小了延误,保证了计算的效率。同时,实现了对公路工作地点的地理位置在电子地图上准确的GPS坐标定位,对管理人员提供了有实际工作意义的公路桩号值,提高了公路管理响应时间和管理水平。

基于VBA自动提取坐标插件的设计及在±0验线中的应用

测绘工作中有很多情况下是需要根据地形图或者CAD图提取需要的坐标并列表输出,少量的点可以人工完成,但是对于有特殊要求或者大量的点,比如在±0验线内业工作"验线较差表"的编制作业中就经常需要采集特征点的坐标值并列表输出,手工操作就差强人意了。本文主要阐述采用VBA编程方法有效解决有固定样式表格编制中坐标值自动写入插件的设计和实际运用,灵活运用此编程的思路,可以衍生很多符合实际工作需要的坐标自动提取输出的插件。

基于卡尔曼滤波器的传像光纤束位置搜索

为获取超高分辨率图像,设计了一种入端为线阵排列、出端为面阵排列的传像光纤束.利用该光纤束的成像系统在合成目标图像时,需要建立光纤束出端、入端位置坐标表.介绍了一种基于卡尔曼滤波器的算法,对出端光纤位置逐一搜索;搜索光纤位置时区分层内、层间设置不同初始步长,按均方误差最小原则对搜索步长进行修正.算法采用了比对终止边界、标定已搜索光纤两种稳健性措施,‘Z’字型搜索路径提高了算法效率.实验结果表明,搜索算法得到的位置坐标表准确标定光纤位置,提取光纤束耦合的信息还原了目标图像.

在MapInfo中实现区域对象样点布设功能

随着GIS在森林资源管理中应用的不断深入,在GIS系统中实现林业专业抽样设计功能是非常必要的。本文使用MapBasic编程语言实现三种样点布设功能。操作时,用鼠标点击欲布样点区域,在弹出对话框中作出回答,就能得到样点布设图和样点坐标表。

一种传像光纤束起点位置搜索的方法

提出一种基于逐行扫描算法改进的光纤束起点位置搜索方法。在图像采集阶段,由于手动放置CCD很难与光纤束出端完全平行,导致采集到的光纤束图像出现倾角,利用最小二乘法和双线性差值方法校正图像。在光纤束起点位置获取阶段,针对传统’Z’字型搜索算法存在的问题,采取每行只搜索横坐标小于一行像素数1/3的方法。实验结果表明该法避免了搜索错误,同时保证了搜索高效率。

Variable-coordinate forward modeling of irregular surface based on dual-variable grid

The mapping method is a forward-modeling method that transforms the irregular surface to horizontal by mapping the rectangular grid as curved; moreover, the wave field calculations move from the physical domain to the calculation domain. The mapping method deals with the irregular surface and the low-velocity layer underneath it using a fine grid. For the deeper high-velocity layers, the use of a fine grid causes local oversampling. In addition, when the irregular surface is transformed to horizontal, the flattened interface below the surface is transformed to curved, which produces inaccurate modeling results because of the presence of ladder-like burrs in the simulated seismic wave. Thus, we propose the mapping method based on the dual-variable finite-difference staggered grid. The proposed method uses different size grid spacings in different regions and locally variable time steps to match the size variability of grid spacings. Numerical examples suggest that the proposed method requires less memory storage capacity and improves the computational efficiency compared with forward modeling methods based on the conventional grid.

Seismic wavefield modeling in media with fluid-filled fractures and surface topography

We present a finite difference （FD） method for the simulation of seismic wave fields in fractured medium with an irregular （non-fiat） free surface which is beneficial for interpreting exploration data acquired in mountainous regions. Fractures are introduced through the Coates-Schoenberg approach into the FD scheme which leads to local anisotropic properties of the media where fractures are embedded. To implement surface topography, we take advantage of the boundary-conforming grid and map a rectangular grid onto a curved one. We use a stable and explicit second-order accurate finite difference scheme to discretize the elastic wave equations （in a curvilinear coordinate system） in a 2D heterogeneous transversely isotropic medium with a horizontal axis of symmetry （HTI）. Efficiency tests performed by different numerical experiments clearly illustrate the influence of an irregular free surface on seismic wave propagation in fractured media which may be significant to mountain seismic exploration. The tests also illustrate that the scattered waves induced by the tips of the fracture are re-scattered by the features of the free surface topography. The scattered waves provoked by the topography are re-scattered by the fractures, especially Rayleigh wave scattering whose amplitudes are much larger than others and making it very difficult to identify effective information from the fractures.

Development of dynamic-mathematical model of hydraulic excavator

This work deals with analysis of dynamic behaviour of hydraulic excavator on the basis of developed dynamic-mathematical model.The mathematical model with maximum five degrees of freedom is extended by new generalized coordinate which represents rotation around transversal main central axis of inertia of undercarriage.The excavator is described by a system of six nonlinear,nonhomogenous differential equations of the second kind.Numerical analysis of the differential equations has been done for BTH-600 hydraulic excavator with moving mechanism with pneumatic wheels.

Simplest Normal Forms of Generalized Neimark-Sacker Bifurcation

The normal forms of generalized Neimark-Sacker bifurcation are extensively studied using normal form theory of dynamic system. It is well known that if the normal forms of the generalized Neimark-Sacker bifurcation are expressed in polar coordinates, then all odd order terms must, in general, remain in the normal forms. In this paper, five theorems are presented to show that the conventional Neimark-Sacker bifurcation can be further simplified. The simplest normal forms of generalized Neimark-Sacker bifurcation are calculated. Based on the conventional normal form, using appropriate nonlinear transformations, it is found that the generalized Neimark-Sacker bifurcation has at most two nonlinear terms remaining in the amplitude equations of the simplest normal forms up to any order. There are two kinds of simplest normal forms. Their algebraic expression formulas of the simplest normal forms in terms of the coefficients of the generalized Neimark-Sacker bifurcation systems are given.

An Approach to Representing Heterogeneous Non-Uniform Rational B-Spline Objects

The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline （NURBS） entity. According to the characteristics of NURBS, a novel data structure, named NURBS material data structure, is proposed, in which the geometrical coordinates, weights and material coordinates of NURBS heterogene- ous objects can be represented simultaneously. Based on this data structure, both direct representation method and inverse construction method of heterogeneous NURBS objects are introduced. In the direct representation method, three forms of NURBS heterogeneous objects are introduced by giving the geometry and material information of con- trol points, among which the homogeneous coordinates form is employed for its brevity and easy programming. In the inverse construction method, continuous heterogeneous curves and surfaces can he obtained by interpolating discrete points and curves with specified material information. Some examples are given to show the effectiveness of the pro- posed methods.

A Semi-Analytical Approach to Green＇s Functions for Problems in Multiply-Connected Regions on a Spherical Surface

This work aims at potential fields generated by point sources in conductive perforated fragments of spherical shells. Such fields are interpreted as profiles of Green＇s functions of relevant boundary-value problems stated in multiply-connected regions for Laplace equation written in geographical coordinates. Those are efficiently computed by a modification of the method of functional equations, with closed analytical forms preliminary obtained for Green＇s functions for the corresponding simply-connected regions.

Interaction of Waves, Surface Currents, and Turbulence: the Application of Surface-Following Coordinate Systems

Surface waves comprise an important aspect of the interaction between the atmosphere and the ocean, so a dynamically consistent framework for modelling atmosphere-ocean interaction must take account of surface waves, either implicitly or explicitly. In order to calculate the effect of wind forcing on waves and currents, and vice versa, it is necessary to employ a consistent formula- tion of the energy and momentum balance within the airflow, wave field, and water column. It is very advantageous to apply sur- face-following coordinate systems, whereby the steep gradients in mean flow properties near the air-water interface in the cross-interface direction may be resolved over distances which are much smaller than the height of the waves themselves. We may account for the waves explicitly by employing a numerical spectral wave model, and applying a suitable theory of wave–mean flow interaction. If the mean flow is small compared with the wave phase speed, perturbation expansions of the hydrodynamic equations in a Lagrangian or generalized Lagrangian mean framework are useful: for stronger flows, such as for wind blowing over waves, the presence of critical levels where the mean flow velocity is equal to the wave phase speed necessitates the application of more general types of surface-following coordinate system. The interaction of the flow of air and water and associated differences in temperature and the concentration of various substances (such as gas species) gives rise to a complex boundary-layer structure at a wide range of vertical scales, from the sub-millimetre scales of gaseous diffusion, to several tens of metres for the turbulent Ekman layer. The bal- ance of momentum, heat, and mass is also affected significantly by breaking waves, which act to increase the effective area of the surface for mass transfer, and increase turbulent diffusive fluxes via the conversion of wave energy to turbulent kinetic energy.

Evaluation of a global eddy-permitting hybrid coordinate ocean model

A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea surface temperature(SST),the zonally averaged seasonal cycle of SST,the variability of the sea level anomaly(SLA),the zonally and meridionally averaged temperature and salinity,and the equatorial undercurrent.It is found that the simulated seasonal cycle of SST is 0.2–0.8 stronger than observed at midlatitudes.The modeled SST is 0.29°C warmer than the observed for the global ocean.the structure of the subsurface temperature and salinity is similar to the observed.moreover,the variability of SLA exhibits the same pattern as observed.The modeled equatorial undercurrent in the pacific ocean is weaker than observed,but stronger than the ecco reanalysis product.overall,the model can reproduce the large-scale ocean states,and is suitable for analyses seeking to better understand the dynamics and thermodynamics of the upper ocean,as well as ocean variability.

一种数字预失真器的实现方法

针对功率放大器引起的非线性失真问题,提出一种基于极坐标查找表的数字基带预失真系统,使用Altera DSP Builder Quartus II等工具软件完成该系统的设计、综合与适配。仿真及实验结果表明,该系统能较好的补偿功率放大器的非线性失真,且具有占用现场可编程门阵列(FPGA)硬件资源少,系统复杂度低的特点。

A new approach to the time evolution of characteristic function of the density operator obtained by virtue of thermal entangled state representation

Like the progress made by Dirac that wave function ψ(x) was reformed as x |ψ,where x| is the coordinate representation,we endow the characteristic function χλ = Tr(e λa-λaρ) of density operator ρ with the meaning of wave function of |ρ in the thermal entangled state η| representation in the doubled Fock space,χλ = η = λ|ρ,where |ρ = ρ|η = 0.We find the time evolution of χλ can then be directly and neatly obtained via this approach.The way of deriving the density operator from η = λ | ρ is also presented.

s-ordering operator expansions of quantum-mechanical fundamental representations and their applications

We show that the quantum-mechanical fundamental representations, say, the coordinate representation, the coherent state representation, the Fan-Klauder entangled state representation can be recast into s-ordering operator expansion, which is elegant in form and has many applications in deriving new operator identities. This demonstrates that Dirac's symbolic method can be merged into Newton-Leibniz integration theory in a broad way.