A study on program evaluation and review technology based on cloud model

When using program evaluation & review technology (PERT), we have to estimate the duration of the activity in the network diagram by our subjective experience. This kind of estimation has biggish subjectivity and uncertainty, so the error between the plan work and the actual work is very large. Cloud is a kind of uncertainty transiting model between some qualitative concept described by lingual value and its numerical value expression, uses Ex(expected value), En(entropy) and He(hyper entropy) to represent the qualitative concept and integrates the fuzziness and randomicity of the concept together, as well as constitutes the mapping between qualitative concepts and quantitative numerical values. Firstly, this paper introduced the principle of cloud model, then applied it to estimate the duration of the work activity in the network of PERT, and finally gave a case to illustrate its effectiveness. The application of cloud model into PERT can effectively resolve the uncertain problem of the work duration estimation under the traditional way.