利用灰色理论数据预测及MATLAB代码(数学建模)

Building feasible models

It recognizes that there exist a few models to estimate of future performance

using currently-available data. For these different methods, each model has

some advantages or disadvantages. According to the existing forecasting

theory, two models can be offered here:

polynomial fitting model

During the engineering and scientific research, people usually represent the

relationship between two different variables and the variation tendency with

the aid of smooth curve on the condition that several reliable data are known.

It is supposed that all the original data has several noisy records, as the

result ,the function we get only presents the variation trend. Fitted curve is not

required to pass all the known data. We use Minimum variance function to

assure that the global error during the fitting progress is the minimum.

Grey Theory Prediction Model

Within the grey system, some of the data are known and the others are

unknown. In addition, their relationships are uncertain. The coral of the model

is to find regular pattern after the Handling Processing of the original data.

Comparison of the two model:

We choose the PH of the Suzhou Xishan from week 25 to 34 as the

original data.

Suzhou Xishan

WEEK PH

25 7.56

26 7.26

27 7.31

28 7.47

29 7.6

30 7.41

31 7.55

32 8.0

33 7.55

From: China's Ministry of

Environmental Protection (MEP)

1.grey system

according to this, after the Accumulated Generating Operation to the original

data, new rec