Software and FPGA-Based Hardware to Accelerate Machine Learning Classifiers

Abstract

This thesis improves the accuracy and run-time of two selected machine learning algorithms, the first in software and the second on a field-programmable gate array (FPGA) device. We first implement triplet loss and triplet mining methods on large margin metric learning, inspired by Siamese networks, and we analyze the proposed methods. In addition, we propose a new hierarchical approach to accelerate the optimization, where triplets are selected by stratified sampling in hierarchical hyperspheres. The method results in faster optimization time and in almost all cases, and shows improved accuracy. This method is further studied for high-dimensional feature spaces with the goal of finding a projection subspace to increase and decrease the inter- and intra class variances, respectively.

We also studied hardware acceleration of random forests (RFs) to improve the classification run-time for large datasets. RFs are a widely used classification and regression algorithm, typically implemented in software. Hardware implementations can be used to accelerate RF especially on FPGA platforms due to concurrent memory access and parallel computational abilities. This thesis proposes a method to decrease the training time by expanding on memory usage on an Intel Arria 10 (10AX115N 3F 45I2SG) FPGA, while keeping high accuracy comparable with CPU implementations.