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1.
Janis Britals 《Celestial Mechanics and Dynamical Astronomy》1992,54(4):305-316
It is shown in this paper how to build a canonical transformation of variables, so that the eccentric anomaly becomes the new independent variable. In the case of eccentric elliptical orbits it changes the equations of motion so, that they can be integrated analytically to any order of approximation comparatively easy. 相似文献
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Vacheslav Emel'yanenko 《Celestial Mechanics and Dynamical Astronomy》2002,84(4):331-341
A new symplectic algorithm is developed for cometary orbit integrations. The integrator can handle both high-eccentricity orbits and close encounters with planets. The method is based on time transformations for Hamiltonians separated into Keplerian and perturbation parts. The adaptive time-step of this algorithm depends on the distance from a centre and the magnitude of perturbations. The explicit leapfrog technique is simple and efficient. 相似文献
3.
Innocent Miebaka Aprioku 《Applied geography (Sevenoaks, England)》2004,24(4):323-338
The paper examines why Yenagoa, the major town and headquarter of Bayelsa State in Nigeria, is experiencing territorial problems, including boundary disputes, which do not exist in larger, fast growing urban areas in Nigeria (such as Lagos, Port Harcourt, Kano and Ibadan). For the purpose of data collection, Yenagoa is divided into 14 zones. A questionnaire survey sought to discover the pattern of interzonal relocation and space preference of residents. An index of environmental deterioration was devised through a measure of the total number, length and width of the stream channels, drainage density, area subject to flood pondage and percentage dry land available for urban expansion in each zone.Using correlation technique to relate environmental quality with relocation and space preference, the resultant indices show two sets of relationships: that there is a direct association between degree of environmental deterioration and desire to relocate, and that the degree of environmental stability of a zone is directly related to its relative attractiveness. Based on these cause–effect relationships, it is argued that Yenagoa has exceeded its carrying capacity. Consequently, there is a fusion of Yenagoa with its neighbouring zones who are resisting the territorial expansion of Yenagoa engineered by the urbanization process. The paper suggests urgent reclamation of flood prone areas in Yenagoa. 相似文献
4.
本文提出了缓和曲线的拟合圆弧的概念,首先确定直线与拟合圆弧的交点,将拟合圆弧的交点桩号作为直线与缓和曲线交点的初始桩号,算出其中桩坐标与走向方位角,再由初始交点向直线作垂线算出初始桩号的改正数,实现了交点桩号的直接解算。 相似文献
5.
本文以常州市青果巷历史建筑测绘为实例,介绍了古建筑测绘的技术路线及新方法的应用,即通过近景摄影测量技术对古建的单体和立面进行测量,借助相应的软件在计算机内恢复古建的真实立体空间,经过像片的纠正处理绘制数字古建测绘成果,具有实际应用意义. 相似文献
6.
Nonlinear static methods are reliable in the evaluation of the seismic response of planar structural schemes, but they are not very effective in the assessment of three-dimensional building structures. The authors of this paper have recently proposed a nonlinear static approach for asymmetric structures, which is an improvement on that stipulated by seismic codes. This method is based on the observation that the distribution of the maximum dynamic displacements of the deck can be enveloped by two pushover analyses performed by applying the lateral force with two eccentricities with respect to the center of mass of the deck. These eccentricities, named “corrective eccentricities”, are defined so that the two corresponding pushover analyses provide displacements that are equal to those evaluated by nonlinear dynamic analysis at the two sides of the deck. In this paper, the corrective eccentricities are determined for a wide set of single-story systems. The equations for their analytical evaluation are determined and their reliability is demonstrated. Finally, the analysis of a multi-story structure is conducted to show how the method can be applied to real buildings. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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该文说明“修正曲线方程”与“曲线方程”的差异及其建立的过程。曲线方程实质上是采用直线方程表达的两相关函数的关系式。但是,按直线方程发展趋势推测的范围较小,误差较大。而修正曲线方程是在曲线方程的基础上探索出的一种新的计算方法。它将曲线方程y=a+bx中的参数(a、b)由常数值导成随x变化的不定值(a_i、b_i)。因此,修正曲线方程则是拟合曲线自然发展的一种方程式。函数的变化规律基本上是沿曲线变化的。它推测的较远,结果误差较小,可广泛应用于水文地质、工程地质等不同学科的领域中。 相似文献
9.
刘丁酉 《武汉大学学报(信息科学版)》1988,13(3):90-100
本文在[1]的基础上提出了秩亏的带权测量平差模型中禾知参数向量的一种线性有偏估计——秩亏网伪逆平差值的修正估计,并着重讨论了该估计在均方误差意义下改进最小二乘估计的优越性、可容许性及新产生的偏差。最后通过实例验证了所得结果。 相似文献
10.
Florent Deleflie Gilles Métris Pierre Exertier 《Celestial Mechanics and Dynamical Astronomy》2006,94(1):105-134
This paper presents an analytic solution of the equations of motion of an artificial satellite, obtained using non singular
elements for eccentricity. The satellite is under the influence of the gravity field of a central body, expanded in spherical
harmonics up to an arbitrary degree and order. We discuss in details the solution we give for the components of the eccentricity
vector. For each element, we have divided the Lagrange equations into two parts: the first part is integrated exactly, and
the second part is integrated with a perturbation method. The complete solution is the sum of the so-called “main” solution
and of the so-called “complementary” solution. To test the accuracy of our method, we compare it to numerical integration
and to the method developed in Kaula (Theory of Satellite Geodesy, Blaisdell publ. Co., New York. 1966), expressed in classical
orbital elements. For eccentricities which are not very small, the two analytical methods are almost equivalent. For low eccentricities,
our method is much more accurate. 相似文献