This paper analyzes the measuring errors of the phasor measurement unit (PMU) and points out the necessity of state estimation based on PMU measurement.

分析了相量量测装置的量测误差情况，指出了相量量测参与状态估计计算的必要性。

youdao

It teaches in simple and easy to follow progressive steps how to attain this coveted state of inner peace, right here where you are, without the necessity of making any outer changes in your life.

它用简单易学、循序渐进的方法来教给你如何从此刻的状态达到你梦寐以求的精神状态，而无需做任何外部的变化。

youdao

For some people, a state of deep focus is office nirvana. For others, perpetual distraction is an office necessity.

对一些人来说，注意力高度集中是办公室必须的，而对另一些人来说，不断地发散是办公室的必须品。

youdao

Scrooge, the boy, because a victim of that, believed that want was an ontological necessity, rather than a tragic by-product of state planning.

FORBES: Malthus and Scrooge: How Charles Dickens Put Holly Branch Through The Heart Of The Worst Economics Ever

Tzipi Livni, of the centrist Kadima party, and Labour leader Ehud Barak both say they are believers in the creation of a Palestinian state, seeing it as a necessity if Israel is to remain both democratic and Jewish in character in the face of Palestinian population growth.

BBC: Israeli election: Where they stand

The majority of Danish politicians intuitively believe that capitalists are an unpleasant necessity to generate the revenues to fund the social welfare state.

FORBES: European Socialism: Why America Doesn't Want It