The non-equal-interval direct new information Verhulst GM(1,1) model with two times fitting and its application to test data processing

The non-equal-interval direct Verhulst new information GM(1,1) model with two times fitting was built which extended equal interval to non-equal-interval and suited for general data modeling and estimating parameters of direct Verhulst GM(1,1). The new model chooses the nth component of X
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as the starting conditions of the grey differential model. The new model need not pre-process the primitive data, accumulated generating operation (AGO) and inverse accumulated generating operation (IAGO). It was not only suited for equal interval data modeling, but also for non-equal interval data modeling. As the new information is fully used, the accuracy of fitting is higher. The example shows that the new model is simple and practical. The new model is worth expanding and applying in test data processing or test on-line monitoring.