Table 4, EfficientNet CNN performed the best result
on the BreakHis dataset, achieving an accuracy of
98.86%. Additionally, we report the best alpha (α)
and the best optimizer, which in this case is Adam.
Moving to the right side of Table 4, we find that
the ShuffleNet performed the best on the Biglycan
dataset, achieving an accuracy of 97.06% based on
the validation accuracy.
Figure 2 presents loss and accuracy graphs to en-
rich our understanding of the generalization capacity
of the better CNNs on the evaluated datasets. For the
BreakHis, it is worth noting that CNN EfficientNet
has a gradual learning process over epochs. Nonethe-
less, for the dataset Biglycan and ShuffleNet, it is sug-
gestive that up until the 20
th
epoch, there is a pro-
gressive and suggestive learning pattern. However,
in the subsequent epochs, the optimization function
behaves inconsistently, resulting in irregular weights
adjustment of the CNN throughout the epochs.
We selected the best CNN for each dataset based
on the accuracies reported in Table 4. Therefore, we
evaluated the influence of the optimizer and learning
rate (LR) factors on the accuracies of these CNNs.
The first set of experiments aimed to ensure that
the CNNs were able to generalize on both datasets,
BreakHis and Biglycan. The accuracy achieved on the
BreakHis dataset is comparable to the state-of-the-art.
However, Biglycan presented greater challenges for
the CNNs due to its limited number of images. The
second set of experiments involved combining differ-
ent configurations and testing these combinations in a
partial factorial design.
Table 5 presents the validation accuracies for
different combinations of optimizers and learning
rates (LR). For the BreakHis dataset, the CNN that
achieved the highest performance (98.86%) was Effi-
cientNet, using the Adam optimizer and LR of 0.001.
Meanwhile, the best CNN for the Biglycan dataset
was ShuffleNet, with an accuracy of 97.07% and us-
ing Adam optimizer and LR of 0.001. Tables 6 and 7
report the results of the second set of experiments in
phase three (3) of our method.
Table 6 reports the percentage of influence of
each factor (q
A
, q
B
, and q
AB
) on the response vari-
able, validation accuracy. The results obtained for the
BreakHis dataset (Table 6) allow us to infer that the
influence of Factor A, i.e., the optimizer alone, rep-
resents an impact of approximately 21.41% on the
response variable, validation accuracy. On the other
hand, Factor B (learning rate – LR) isolated repre-
sents an impact of approximately 23.60% on the re-
sponse variable, validation accuracy. Lastly, we ob-
served that the influence of Factors A and B (Opti-
mization Function and Learning Rate) simultaneously
has a predominant impact of approximately 55.00%
on the response variable, validation accuracy.
We sought to understand whether this behavior
of the optimizer and learning rate factors’ influence
(q
A
, q
B
, and q
AB
) carries over to other problems and
datasets. Therefore, we carried out a performance
evaluation using the Biglycan dataset and reported our
findings in Table 7. We found that the influence of
the optimizer and learning rate factors changes across
problem classes and datasets. This perception is sup-
ported by the fact that the simultaneous influence of
Factors A and B (Optimizer and LR) is negligible, ac-
counting for approximately 1.79%. Meanwhile, Fac-
tor A (Optimizer) solely exerted a predominant influ-
ence of approximately 96.41% on the response vari-
able, validation accuracy, for this dataset. On the
other hand, Factor B (LR) alone had a negligible in-
fluence of approximately 1.79%.
Among the numerical findings suggested by our
experiments, it is possible to recognize that formal
analyses of factor influence using the partial factorial
method can help guide optimization efforts toward
factors that truely impact validation accuracy. Hy-
perparameter optimizers are recommended for fine-
tuning CNNs, and the insights from our experiments
can inspire new criteria for hyperparameter optimiza-
tion, directing the tuning toward the search spaces of
factors that have a predominant influence over others.
Finally, our best results achieved for each dataset
were compared with other state-of-the-art approaches
in the literature, as presented in Table 8. Our findings
indicate that our best score exceeds the performance
of the best state-of-the-art technique reported in pre-
vious studies.
5 CONCLUSION
This paper evaluated the extent to which two factors
(optimization function and learning rate) influence the
response variable and validation accuracy. To accom-
plish this, we proposed a three-fold method, where the
initial two (2) phases involved training and validat-
ing six different CNNs using various parameter com-
binations and the two datasets, BreakHis and Bigly-
can. Subsequently, in the third phase, we selected two
(2) CNNs that outperformed the others in the classi-
fication task and conducted a performance evaluation
based on the sum of squares.
We found that the CNNs EfficientNet and Shuf-
fleNet empirically outperformed the others in the clas-
sification task on the BreakHis and Biglycan datasets,
achieving accuracies of 98.86% and 97.06%, both re-
spectively. Additionally, our paper introduces an in-
VISAPP 2024 - 19th International Conference on Computer Vision Theory and Applications
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