中文摘要：

通过分析影响项目进度的两种类型不确定因素,提出从不确定因素视角认识安全时间,并消减偶然性不确定因素加入的安全时间。在分析项目实施中可能由偶然性不确定因素引发的风险事件基础上,设计了一种确定缓冲区的新方法。该方法考虑了导致安全时间加入的两种因素,在严格控制偶然性风险事件下项目进度能按其期望概率执行。

英文摘要：

By analyzing the two types of uncertainties which affect project schedule,the paper proposes to recognize safety time from the perspective of uncertainties,and subtractes the safty time which was triggered by aleatory uncertainties.The paper developes a new approach to setting the buffers based on analyzing the risk events which were triggered by the aleatory uncertainties in the process of project implementation.This approach considers two factors which induce the safety time,then the project schedule can be executed according to its expected probability when aleatory risk events are strictly controlled.