查询词典 stratified sampling

The quantizing error, linear error and differential linear error of an A/D converter were deduced, after that the error model of synchronous sampling, asynchronous sampling and quasi-synchronous sampling algorithms used in power measurement wens build in condition that A/D was not perfect.

建立了该两种乘法器的物理模型，数学模型和误差仿真模型，全面地分析了各种参量对其交流功率测量的原理误差和仪器误差的影响，并给出了定量的结果。

The main sampling methods include contiguous grid quadrats sampling and random communities sampling.

常用的取样方法有梯度格局法和典型群落随机取样法，其中最小取样面积的确定尤为关键。

At first the current sampling values pass through virtual digital CVTs. And then the voltage and current sampling values are processed by a low pass filter. According to the instantaneous value of transmission line voltage, the current instantaneous values of shunt reactors and P equivalent circuit capacitance can be calculated. After removing these two kinds of current, sampling value differential protection based on all components and fault component can be applied.

由线路电压瞬时值分别实时计算出流入并联电抗器和流入线路Π型等值电路两侧电容的电流瞬时值，再从线路每侧电流除去这两部分电流，用得到的新电流瞬时值作常规采样值差动和故障分量采样值差动保护计算。

A mathematic model based on APQ was develop ed with a sampling rate and maximum false alarm rate as inputs to determine the optimum sampling size, sampling freq...

该方法包含了涉及控制图设计的所有关键元素，但是它比控制图的经济和半经济设计模型简单易用。

METHODS: 5 184 people of non-manual workers and manual workers in city as well as farmers at different sex, aged from 20-59 years, were selected in Shijiazhuang, Cangzhou and Chengde with random sampling of stratified cluster in July 2000. They were assigned into 20-39 year group and 40-59 years group according to age to perform investigation of their physical work, which composed of strength of grasp, anteflexion of body when sitting, standing with single foot when closing eyes, back pressure, vertical jump, 10 m×4 return run, push-up, sit-up and choice of reaction time, etc. RESULTS: 4 800 people were involved in the result analysis.

于2000-07用分层整群的随机抽样方法抽取石家庄、沧州、承德3个城市不同性别的城市非体力劳动者、城市体力劳动者、农民3类职业人群的20～59岁公民5184名，按年龄分为20～39岁组和40～59岁组两组，对其进行体能测查，测查内容包括握力、坐位体前屈、闭眼单脚站立、背力、纵跳、10m×4往返跑、俯卧撑、仰卧起坐、选择反应时等。

Methods Stratified random and cluster sampling methods were employed in this study.

正确使用安全、可靠的避孕方法是降低意外妊娠的关键。

Methods With stratified cluster sampling method,2 519 students were questionnaired in Anhui province.

采用分层整群抽样方法，对安徽省2519名中小学生进行问卷调查。

Methods Stratified cluster sampling was used to investigate villagers with questionnaire.

采用分层整群随机抽样方法，对家中有流动人口的村民进行调查。

Methods : A questionnaire survey was conducted among 411 medical staff in 15 departments by stratified cluster sampling.

采用分层随机整群抽样方法，对我院15个部门中的411在职医务人员进行问卷调查。

To interview1483 residents of 15 years and above by the way of stratified and cluster sampling.

通过分层整群抽样访谈调查了黑水县15岁以上居民1483人。

We are forbidden from giving money to these shoeless, skinny children, as this will perpetuate begging.

向光着脚，骨瘦如柴的孩子施舍是不可以的，因为要招来无休无止的乞讨。

It would be hard not to fall victim to some sharpeyed policeman.

要想不被某个目光锐利的警察抓到，谈何容易。