Study on a grey Verhulst self-memory model and application

General grey Verhulst model for sigmoid process boasts good prediction accuracy. But the prediction accuracy is not high enough for fluctuant sigmoid process. In order to improve prediction accuracy, the grey Verhulst self-memory model was established based on grey system and self-memory principle. The model can recollect the historical data and get over grey Verhulst model´s shortages. Examples show that the suggested model can reflect the fluctuant trend of sigmoid process with satisfactory simulation and prediction precision.