在某些时间段，有三种罗非鱼在那里生长。
校园网账号管理系统缺乏时间约束，造成用户账号在某些时间段上易被攻击和盗用。
The account management system of campus network has not temporal constraints, its account Numbers are easily attacked and embezzled during some periods.
分析了海上机动目标的运动特性，针对海上机动目标在某些时间段运动具有一定的规律性，用插值外推法建立了预测其运动的数学模型。
To track the maneuvering targets, an improved adaptive tracking algorithm based on truncation normal models is proposed, which has the properties of simple computing and strong robustness.
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