Core Concepts
Convolutional Kolmogorov-Arnold Networks (ConvKANs), employing learnable spline-based activation functions within convolutional layers, offer a promising alternative to traditional CNNs, demonstrating competitive accuracy with significantly fewer parameters in image classification tasks.
Abstract
Bibliographic Information:
Bodner, A. D., Spolski, J. N., Tepsich, A. S., & Pourteau, S. (2024). Convolutional Kolmogorov-Arnold Networks. arXiv preprint arXiv:2406.13155v2.
Research Objective:
This paper introduces Convolutional Kolmogorov-Arnold Networks (ConvKANs), a novel neural network architecture that integrates learnable spline-based activation functions from Kolmogorov-Arnold Networks (KANs) into convolutional layers, aiming to improve parameter efficiency in image classification tasks.
Methodology:
The authors propose replacing traditional convolutional kernels with KAN convolutions, where each kernel element is a learnable non-linear function using B-splines. They design various architectures combining KAN convolutions, fully connected layers (MLPs), and KAN layers, comparing their performance against standard CNN architectures on the Fashion-MNIST dataset. Hyperparameter tuning is performed using grid search, and models are evaluated based on accuracy, parameter count, and training time.
Key Findings:
- ConvKANs demonstrate competitive accuracy compared to traditional CNNs on the Fashion-MNIST dataset, often achieving similar performance with significantly fewer parameters.
- Smaller ConvKAN models, particularly those using MLPs after flattening, outperform CNNs of comparable size, suggesting that KAN convolutions might "learn more" per kernel.
- Increasing the depth of MLPs in larger models gives classic convolutions a slight advantage, indicating a potential shift in learning towards the fully connected layers.
- Grid size for B-splines significantly impacts accuracy and requires careful tuning.
Main Conclusions:
ConvKANs present a promising alternative to traditional CNNs for image classification, exhibiting the potential for achieving high accuracy with reduced parameter complexity. The use of spline-based activation functions within convolutional layers allows for efficient learning and representation of spatial information.
Significance:
This research contributes to the field of deep learning by introducing a novel architectural design that enhances parameter efficiency in CNNs. The findings have implications for developing more lightweight and computationally efficient models for image-related tasks.
Limitations and Future Research:
- The current implementation of KANs with B-splines suffers from slow training times due to limited GPU parallelization. Exploring alternative function approximators like Radial Basis Functions could address this limitation.
- Further experimentation on more complex datasets like CIFAR-10 or ImageNet is necessary to validate the scalability and generalization of ConvKANs.
- Investigating the interpretability of KAN convolutions and developing effective pruning techniques are crucial for practical applications.
Stats
KANC MLP (Small) achieves 88.15% accuracy with almost 15k parameters.
CNN (Big) achieves 89.44% accuracy with ∼26.62k parameters.
KKAN (Small) achieves 87.67% accuracy with 22k parameters.
Conv & KAN (Small) achieves 88.01% accuracy with 38k parameters.
KKAN (Medium) achieves 88.56% accuracy with 74875 parameters.
Quotes
"The main strength of the Convolutional KANs is its requirement for significantly fewer parameters compared to other architectures."
"KAN Convolutions seem to learn more per kernel, which opens up a new horizon of possibilities in deep learning for computer vision."
"In the current experiments, adding KAN kernels keeping the same number of Convolutional layers seem to faster reach a limit on the accuracy increase, while with classic convolutions it seems to be necessary to achieve a higher accuracy."