Examining the Impact of Network Architecture on Extracted Feature Quality for CBR.

Classification accuracy for case-based classifiers depends critically on the features used for case retrieval. Feature extraction from deep learning classifier models has proven a useful method for generating case-based classifier features, especially for domains in which manual feature engineering is costly or difficult. Previous work has explored how the quality of extracted features is influenced by structural choices such as the number of features extracted and the location/depth of extraction. This paper investigates how feature quality is influenced by another factor: the choice of the network model itself. We consider a selection of deep learning models for a computer vision classification task and test the accuracy of a case-based classifier using features extracted from them, both as the sole feature source and in combination with a supplementary set of knowledge-engineered features. Results suggest that feature quality reflects a trade-off between model complexity and training data requirements and provide lessons for the selection of deep learning architectures for feature extraction to support case-based classification.