The rainfall Intensity Duration Frequency formula is one of the bases in hydrology calculation, and has been of considerable interest to engineers and hydrologists.

降雨公式是水文计算的基本依据之一，也是工程师和水文学家十分关心的问题。

youdao

In this model, running state of transmission line is divided into four states, and calculation method of state probability, state frequency and state duration in balanced state are given.

该模型将输电线路的运行状态划分为四种状态，给出了每种平稳状态的状态概率、状态频率和状态持续时间的计算方法。

youdao

The calculation of heating duration and energy consumption can provide basis for on standardized heating-design as well as reference for the energy-saving for the multi-span greenhouse.

大型温室采暖期的确定及采暖能耗的计算可为中国连栋温室采暖设计标准化提供依据，为温室节能提供参考。

youdao

Also, mortgages have a duration (a calculation of the time it takes to get paid back) that is a variable, hypothetical duration that varies with prepayment speeds, so a short duration mortgage portfolio is not protection against a sudden increase in interest rates, because if interest rates rise the duration will rise which hurts the value of the bond.

FORBES: A Haven From A Eurozone Crash: Investment Grade Bonds