精度

Precision and results are rounded to double precision when copied to double precision variables in RAM/cache.

普通 FP 算术和 SSE2 分级算术的最大不同是，FP 算术使用扩展的精度执行，当用 RAM/cache 复制到双精度变量时，结果也被

The effects of standard deviation of random variables and system size on computational accuracy are investigated by several numerical examples and two points estimate method are recommended when computational accuracy and execution time are considered in a comprehensive way.

数值仿真分析了随机变量标准差和系统规模对点估计法计算精度的影响，并指出在综合考虑计算精度和计算时间的情况下，2点估计法的结果令人满意。

Theoretical analysis and simulation shows that the direction driving motor accelerates first, and then decelerates to compensate for the eccentricity when the satellite is deviated from laser center with a certain distance, and reacquires the tracking satellite. The needed time from reacquisition to tracking is affected by motor acceleration, telescope′s detecting precision, and detector′s response and treatment time, and the effect of detector precision on the reacquisition and re-tracking time is greater, as a result, the detector response and treatment time is decreased to the least.

理论分析与仿真结果表明，当卫星偏离光斑中心一定距离时，指向驱动电机先加速后减速，补偿这个偏心，重新捕获跟踪卫星；重新捕获到跟踪所需时间受电机加速度和望远镜探测精度以及探测器响应处理时间影响，其中探测器精度对重新捕获到跟踪所需时间影响较大，探测器响应处理时间要减小到最小；为了使从捕获到跟踪过程中卫星始终在扫描光斑范围内，经纬仪驱动电机的最小角加速度为25.5°/s2。

Itsmeasurement accuracywas verified by the three phase p recision test power equipment, and the result shows that themeasuring instrument has highermeasuring accuracy.

实验结果表明：该仪表具有较高的测量精度，可以满足电能测量的精度要求以及电力设备实时监控方面的要求。

The genetic algorithm pays attention to unknown area search . It has high speed and relative low precision. It will not get into local extremum. The BP algorithm searches the area that include whole-space minimum. It can improve speed and recision.

遗传BP算法利用遗传算法进行全局搜索，注重搜索未知区域，处理速度快而对精度要求不高，不易陷入局部极小点，而利用BP算法搜索有最优点的区域，提高搜索速度和精度。

For the measurement system of geometrical p lane parameters based on image measuring technique to the quartz pendulous reed, the calibration p recision of camera system is p rerequisite.

在以图像测量技术为核心的石英摆片平面几何参数检测系统中，视觉测量系统标定精度是保证石英摆片平面几何参数高精度测量的前提。

Astrometry with new technologies created and is dedicated to the Space Telescope astrometric space orbit around the Earth observation and research on the scientific .1989 8 8, the European Space Agency launch astrometric Satellite Iba Valley satellite, which contains a 29 cm diameter reflecting telescope, four ground stations for data reception and analysis with the aim of space-based observations compiled by 120,000 to contain space for satellite measurement of star form, the location accuracy of ± 0002, parallax measurement accuracy ± 0002, on their own a year 0002, CDCDCD preliminary estimate of the above three data are now actual for the 0004,0003 and 0005; CDCDCD190 year in April the U.S. launch of the Hubble Space Telescope, containing 24 m diameter Wang C far mirror can work 15-20 years, 17-18 so you can measure the parallax of stars, are hundreds of thousands of stars of the measurement results.

伴随天体测量新技术而产生，是专门用于天体测量的空间望远镜在围绕地球的空间轨道上进行观测研究的科学。1989年8月8日，欧洲空间局发射天体测量卫星伊巴谷号卫星，它载有口径29厘米反射望远镜，4个地面观测站进行资料接收与分析，目的是要通过空间观测编出含星12万颗的空间测量星表，位置精度为±0002，测量视差的精度为±0002，自行为每年0002，CDCDCD现在初步估计上述三个数据实际为0004、0003和0005；CDCDCD190年4月美国发射哈勃空间望远镜，载有口径24米的望C远镜，可工作15—20年，可以测量出17—18等星的视差，得到几十万颗星的测量结果。

The advantages and limitations of every kind of methods for calculating the failure probability is reviewed. The frist order reliability method, the second order reliability method and many kinds of boundary method have achieved remarkable success and formed nature fields of reliability. However, the precision of these methods decrease as the increase of complexity of problem. The numrical methods are versatile, except numerical intergration is only adaptable to special problems which have small number variables and regular intergral domain. Particularly, the advanced variance reduction techniques own the following character: high precision and a small amount computation. But some questions remain to study in the future because only an initial work about these techniqes is developed.

全面评述了计算失效概率各种方法的优点和局限性，其中经典的解析法包括一次可靠性方法、二次可靠性方法、一阶边界法、Vanmarcke上边界、PENT上边界和Ditlevsen二阶窄边界法，这些方法对于多设计点、变量较多且相关、密度函数不是正态以及极限状态方程较复杂的情况，其计算精度较差；而已有的数值方法却是具有较好的通用性，其中除数值积分法只对变量较少、积分域较规则的特殊问题适用外，各种数值模拟方法均具有较广的适应性，特别是各种改进的方差减小技术，精度高、计算量小，但由于其处在研究的初级阶段，还有许多问题有待于解决。

For plants with relative degree greater than one, the tracking performance of the MRRC may be unacceptable.

该设计方案的主要缺点是跟踪精度过分依赖控制增益：较高的跟踪精度需要很大的控制增益。

In this paper, the problem of the measuring accuracy for the GJ-341 small remote-control optical-electronic theodolite is analyzed and assessed.

本文对GJ-341小型遥控光电经纬仪的测量精度问题进行了较系统的分析与评估，并提出提高GJ-341小型遥控光电经纬仪测量精度的途径。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。