近似法

The question of searching characteristic points or straight lines on moving rigid body is decomposed into two relatively independent sub-questions. The first one is to evaluate the characteristic of points and straight lines on moving rigid body, whose mathematics model is a kind of special non-differential max-mini optimal problem with inequality constraints. By the method of Saddle-point Programming and maximum entropy, the problem can be transformed as a differential optimal problem with single objective. The second oner is to search approximative character points or straight lines on moving rigid body within design space, whose mathematic model is nonlinear and non-differential problem with multiple constraints.

本文将在运动刚体上寻找特征点或直线的优化问题分解为两个相对独立的子问题，一是对运动刚体上点或直线的特征性评定，其实质是平面曲线的圆度或直线度的评定问题，优化模型是以最大误差为最小作为优化目标的约束不可微的优化问题，本文采用鞍点规划和极大熵方法，将其转化为单目标可微优化模型；二是在设计空间内，寻找运动刚体上特征性评定指标最小的近似特征点或直线，其优化模型是非线性、多约束的不可微优化问题，本文提出用遗传算法和BFGS局部搜索法相结合来求解。

In this study, a new algorithm is proposed to solve the nonlinear oscillatory systems.

本研究提出一个新的演算法应用於求解非线性振动系统之近似解析解。

The full parallax CGHs are generated by the point source method and the wave-oriented method without paraxial approximation.

这种全视差计算全息图是由点基元方法和平面波导向法生成并且没有经过旁轴近似。

Using PH linearization ,the nonlinear partial differential equation was transformed into linear partial differential equation,and then,by introducing a complex function,it was further transformed into a set of two linear differential equations.

应用 PH线性化方法，将非线性偏微分方程转化为线性偏微分方程，引入复函数将复常数偏微分方程变为两个线性实常数微分方程组，并采用小参数迭代法进行求解，近似求得了螺旋槽内气体动压分布的解析解。

The paper presents an efficient approximate algorithm for Convex Hull of very large planar point set.

提出了一种计算海量平面点集凸壳的快速近似算法——点集坐标旋转法。

The discharge calculation coefficient k,x can be used to the discharge calculation under the condition of fixed numerical value,solves some special demands in water power planning and design and similar calculation of unsteady flow in the pondage water power station.

马斯京根法流量演进系数K，x，在数值不变的条件下应用于河段短时段的流量演算，解决了水利水电工程规划设计中的一些特殊要求和水电站日调节不稳定流演进的近似计算问题。

Aiming at structural design influence of part physical dimension and uncertainty of exterior load, response surface and several statistic parameter analyse of bridge truss structure bending stress and deflection was proceed by means of probability design and finite element method.

针对桥梁桁架实际设计中，零件结构尺寸、外部载荷的不确定性对结构设计的影响，采用概率设计与有限元技术相结合，通过参数化建模，运用响应面法构造了近似函数，对桥梁桁架弯曲应力和挠度进行了概率设计。

We use the approximate distribution comes from probability generating function of CreditRisk+ to value the CDO under the single sector factor and multi-sector factors scenarios. For single sector factor model, we discuss the sensitive analysis of CDO fair spread by different default probability, default correlation and loss given default. For multi-sector factors model, we exam the CDO fair spread based on different sector correlation assumption, such as Gamma distribution in moment match method, multivariate Gamma distribution and compound Gamma distribution.

本文在信用风险加成模型之下，利用机率产生函数的近似分配评价抵押债务债券，并考虑单一部门因子与多个部门因子，单一部门因子中，在不同违约机率、违约相关系数和违约损失率下，探讨抵押债务债券公平价差之敏感度分析；多个部门因子中，在不同相关性部门因子分配假设下，如动差配适法的伽玛分配、多维伽玛分配、复合伽玛分配，探讨抵押债务债券公平价差之方法结果比较。

Based on the concept of the non-proportional damping which may be divided into the proportional part for dissipation of energy and the nonproportional part for transformation of energy, a new modal superposition pseudo-force method is presented if the approximate decoupling method is not suitable. In this method the coupled modal equations are solved by iteration in which the coupling terms are treated as pseudo-force and set to the right side of the equations.

在不能进行近似解耦分析时，基于非比例阻尼可分为耗散能量的比例部分和转换能量的非比例部分这种概念，建立了一种拟力实模态叠加法，即把正则化的耦合模态方程中代表非比例阻尼部分的耦合项作为虚力，放到方程的右端，再运用迭代法求解。

Use dichotomy for a few equations approximate the real root.

利用二分法求一个方程的实数近似根。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。