精度

Based on the table of matrix element of spectrum decomposition, the Helmhotz matrix can be decomposed by recursion of the direct solution. A numerical comparison has been made with the spectrum LU decomposition and direct solution.

通过与谱法分解和直解法在分解精度和分解速度两方面的比较表明，本文方法与谱法相比，在非均匀介质中亥姆霍兹算子矩阵分解时的精度提高10倍；在计算速度方面，混合方法比简化后的直解法快。

Error analysis of direct georefencing is divided into two parts: for attitude angle error, formula is determined by the error of the direction cosine matrix, for other errors, formula is determined by covariance matrix.

为了分析各误差因素对定位精度的影响，分两步建立各误差因素和定位精度的表达式，对于姿态角误差的影响，为避免欧拉角之间的耦合，按照方向余弦矩阵误差定义求取，对于其余误差的影响，采用协方差矩阵求取。

A test scheme of trajectory measurement in security and reliably with OKA,GPS and total station positioning system(TCRA1101) etc is established.Synchronously,a method is presented on two OKA by direction cosine intersection in the measurement,also two different methods are adopted to check up the precision and the expectant results are obtained.

针对模型自由飞的特点，综合利用两台小型激光电视测量系统、GPS、全站仪（TCRA1101）等现有设备，设计了安全、可靠的模型自由飞跟踪、测量方案；利用方向余弦交会算法，对测量的模型自由飞数据进行处理，并采用两种不同的方法进行了测量精度检查，结果表明测试精度满足测试要求。

Compared with the same wave problems with conventional Dirichlet boundary conditions, the absorbing boundary conditions can reduce the numerical reflection on boundaries and avoid solution distortion. In addition, the central differences method is economic in memory requirement and computing time compared with implicit integral method.

结果表明：该解法在空间上具有谱精度，在时间上达到二阶精度；与第一类边界条件相比，吸收边界有效地削弱了边界上的数值反射，避免了解的失真；使用中心差分的时间积分方法同隐式积分方法相比，适合波的传播特性，避免了矩阵求逆运算，并且占用的计算机内存小。

Fourth precision solution can be derived from two grid sets solution with a second precision central difference scheme by Richardson extrapolation. It reduces the amount of calculation. Uncertainty is determined from the discretization error analysis. A finer grid calculation is made to validate the extrapolation scheme.

对于2阶精度中心差分格式的2套网格数值解，用Richardson外推法可以得到4阶精度的解，其工作量比直接求解4阶离散方程的工作量减少许多；对于计算中的数值不确定度，用该方法分析了离散误差，并用逐次加密网格的方法探讨了外推法的合理性。

The increase of distance in circle neighborhood will decrease the model precision, in the mean while the increase of distance in rectangle neighborhood will increase the precision first then decrease.

环状邻域距离的增大会导致模拟精度的降低，面状邻域距离的增大则导致模拟精度先增后降。不同土地类型对邻域距离变化的敏感程度和反应皆不相同。

In this paper, 3-D tertiary structure of protein fold was mapped into 2-D distance matrix which can be further regarded as gray level image.

最后应用于27类折叠子分类，对独立集测试的精度达到了71.95 %，对所有数据进行10 交叉验证的精度为78.94 %。

On the basis of experimental research, this thesis applies 2-dimensional non-linear finite element method to the analysis of transient temperature field on the section by means of relatively high precision triangular element of six joints. When the temperature field is analyzed, finite element reseaus are divided in space field and finite difference reseaus are divided in time field, and then the program is compiled. The computing results are in good agreement with the test data. It indicates that the program is stable and precise.

在试验研究的基础上，本文采用精度较高的三角形六结点单元对构件截面二维非线性瞬态温度场进行了有限元分析，即在空间域内采用有限元网格划分，在时间域内采用有限差分网格划分，据此编制了计算程序，计算结果与试验数据符合较好，程序稳定性好，精度满足要求。

Double-precision floating number operation was adopted in calculating flowmete and the hardware multiplier embedded in MSP430F149 was used in the program which enhanced the operation precision and speed.

采用双精度浮点数进行流量运算，并在程序中使用MSP430F149内置的硬件乘法器，提高了运算精度与运算速度。

In market the selection of tolerance and cooperation of some certain types Dray is not very consistent with the accuracy, performance and Life requirements of product. Therefore, improvements is made specially in these parts of this design , To achieve Convenient Processing and meet the Requirements of accuracy and performance、Life and Reduce costs .

市面上某些同类型的曳引机产品的公差与配合的选用不是太符合保证产品精度、性能和使用寿命等要求，为此，本设计特别在这些地方做了改进，以达到方便加工，满足精度、性能，使用寿命以及降低成本等要求。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。