5.2. Research Methods
5.2.1. Selection of the Appropriate Chemical Composition
(1) Model Principle
One-way analysis of variance (ANOVA) refers to the method of analyzing the one-way test results and testing whether the factors have a significant impact on the test results.
Assuming that the collected data were derived from the sample values of S different populations (each level corresponds to one population), and counting the mean values of each population in one order, the following assumptions need to be tested:
Null hypothesis: .
Alternative hypothesis: Not all are zero.
To reintroduce the horizontal effect, t
.
Thus, when true, the F-distribution-test statistic that needs to be followed by one-way ANOVA is:
Thus, with the significance level a, the rejection domain of the test problem is:
At this point, the null hypothesis was rejected as showing significant differences between the samples.
(2) Model Building
First, we investigated whether the fourteen chemical components would have a significant effect on the glass-classification results of high-potassium types.
Therefore, we established the following assumptions:
Null hypothesis: The fourteen chemical components will not have a significant impact on the glass-classification results of high-potassium types.
Optional hypothesis: The fourteen chemical components will have a significant impact on the glass-classification results of high-potassium types [
32,
33,
34,
35,
36].
In the ANOVA
Table 6, SiO
2, K
2O, CaO, Al
2O
3, and Fe
2O
3 are less than 0.05. The null hypothesis is rejected in the belief that SiO
2, K
2O, CaO, Al
2O
3, Fe
2O
3, and high-potassium-type glass will affect the classification of high potassium type glass; that is, select these five suitable chemical components to subdivide the subclass of high-potassium-type glass.
Similarly, we investigated whether the fourteen chemical components would have a significant impact on the lead-barium-type-glass-classification results.
Therefore, we established the following assumptions:
Null hypothesis: The fourteen chemical components will not significantly affect the results of lead-barium-type-glass classification.
Optional hypothesis: The fourteen chemical components will have a significant impact on the results of lead-barium-type-glass classification.
In the ANOVA
Table 6, it can be seem that SiO
2, Na
2O, Al
2O
3, CuO, PbO, BaO, BaO, P
2O5, SrO, and SO
2 are less than 0.05, and the null hypothesis that SiO
2, Na2O, Al
2O
3, CuO, PbO, BaO, P
2O
5, SrO, SO
2 and lead-barium-type-glass affect the classification of lead-barium-type glass can be rejected; that is, select the nine appropriate chemical components for lead-barium-type glass.
5.2.2. Subclass Division
(1) Model Preparation
For the problem of using the above chemical components for each category, we use the k-means algorithm.
The K-value setting is the only defect of the algorithm. In order to improve the effectiveness of K value, we used the fast-clustering method to determine the value of K in K-means algorithm and obtained the K value of 3 through systematic clustering in SPSS software [
37,
38].
(2) Model Building
➀ We randomly selected K samples from the sample set as the initial mean vector;
➁ We calculated the distance of the sample from each mean vector and dividedthe sample into the phase according to the nearest mean vector from the sample cluster;
➂ After the classification, the central point of the category was redetermined and the mean of all samples in the category was made. For features corresponding to the new center point, the centroid of all samples in the class was applied;
➃ Steps 2 and 3 were repeated until the subclass subdivision of high-potassium glass with lead barium glass was completed.
(3) Model Solution
Based on the analyzed data, we solved the model using SPSS software and obtained the following results:
High potassium:
{18,7,27,10,12,9,22,21}, {16,14,3,1,4,5,13,6}.
Lead-barium:
{2,34,36,28,29,40,43,52,54,57}, {8,11,19,26,41,51,56,58,24,30},
{23,25,28,29,42,44,48,49,50,53,20,31,32,33,35,37,45,46,47,55}.
5.3. Model Analysis
(1) Rationality Analysis
In order to verify the rationality of the classification results, we used the principal-component-analysis method to cluster the data and compare the observed classification results with the K-means classification results. If the comparison results were not very different, the classification results were reasonable; otherwise, the classification results were not reasonable. According to the results obtained from the above cluster analysis, the data were divided into two categories; therefore, we also extracted the same two categories using the principal-component-analysis method. The principal-component-analysis steps were as follows:
➀ With
n cultural relics and
p indicators, the initial sample matrix is:
➁ Calculate eigenvalues of the inter-index correlation coefficient matrix R and eigenvector and obtain the principal component : .
➂ When the cumulative variance contribution of the j-th principal component is above 80%, take the first q principal components
; it is believed that the few q principal components reflect the information of the original
p evaluation indicators. Formula for the cumulative-variance-contribution rate:
➃ The formula for studying the composite score is as follows:
Next, classifications were performed according to the coefficient size. Based on the coefficient of the principal components, we extracted the cultural-relic numbers with large coefficients and obtained the results presented in
Table 7 [
39,
40].
Based on the above results, we found that although the results of K-means cluster analysis were slightly inconsistent, they were generally the same, which shows that the results essentially did not change with different methods, and that their rationality was strong.
(2) Sensitivity Analysis
During the extraction of the significant chemical-component content, the significance level of the one-way ANOVA was determined to be 0.05. To explore the sensitivity of our classification results, we adjusted the significance levels to 0.01 and 0.1, respectively, and the specific experimental procedures and results were as follows.
Significance level of 0.05: SiO2, K2O, CaO, Al2O3, and Fe2O3. Chemical composition in high-potassium-glass classification: SiO2, NaO, K2O, Al2O3, CuO, CaO, PbO, BaO, Fe2O3, P2O5, SrO, and SO2.
The ➀ significance level was 0.01.
For high-potassium glass, the significance level of the original chemical composition selected had less Fe
2O
3. For lead-barium glass, the extraction of chemical composition as less than the basis of the chemical composition of NaO, Al
2O
3, and SrO. Specific classification results are shown in
Table 8.
The ➁ significance level was 0.1.
For high-potassium glass, the chemical composition extracted at this point was higher in SO
2 than the previously extracted chemical. For lead-barium glass, the extracted chemical composition added CaO to the original significance level. The specific classification results are shown in
Table 8.
The table shows that at the significance levels of 0.1 and 0.01, although the classification of the high-potassium and lead-barium glass was perturbed, fewer relics were disturbed; therefore, we believe that the sensitivity of the lead-barium-glass-classification law is low.
In conclusion, although changing the level of significance can affect the change in classification results, the number of changes is small and exerts a weaker impact on the population; therefore, we believe that the results obtained by the K-means classification are less sensitive.