生产实践中各种因素及具体背景的错综复杂性,使运用网络计划方法优化所得结果与实际情况往往有很大出入。譬如,大型土木工程的建设,其工程进度直接受季节的影响,某些工序用时的预测,如果不与时间背景一同考虑,由此所得的施工计划必须与实际进展难以相符。又如,生产中的人机调配,尽 The intricacies of various factors and specific backgrounds in production practice make it difficult to use the network planning method to optimize the results obtained and the actual situation. For example, in the construction of large-scale civil engineering projects, the progress of the project is directly affected by the seasons. If the forecast of certain processes is not considered together with the time background, the resulting construction plan must be inconsistent with actual progress. Another example is the deployment of man-machine in production.