On the Importance of Capturing a Sufficient Diversity of Perspective for the Classification of micro-PCBs

Pre-print of an original work presented at KES-IDT 2021 held virtually.We present a dataset consisting of high-resolution images of 13 micro-PCBs captured in various rotations and perspectives relative to the camera, with each sample labeled for PCB type, rotation category, and perspective categories. We then present the design and results of experimentation on combinations of rotations and perspectives used during training and the resulting impact on test accuracy. We then show when and how well data augmentation techniques are capable of simulating rotations vs. perspectives not present in the training data. We perform all experiments using CNNs with and without homogeneous vector capsules (HVCs) and investigate and show the capsules' ability to better encode the equivariance of the sub-components of the micro-PCBs. The results of our experiments lead us to conclude that training a neural network equipped with HVCs, capable of modeling equivariance among sub-components, coupled with training on a diversity of perspectives, achieves the greatest classification accuracy on micro-PCB data

Homogeneous vector capsules and their application to sufficient and complete data

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University LondonCapsules (vector-valued neurons) have recently become a more active area of research in neural networks. However, existing formulations have several drawbacks including the large number of trainable parameters that they require as well as the reliance on routing mechanisms between layers of capsules. The primary aim of this project is to demonstrate the benefits of a new formulation of capsules called Homogeneous Vector Capsules (HVCs) that overcome these drawbacks. Using HVCs, new state-of-the-art accuracies for the MNIST dataset are established for multiple individual models as well as multiple ensembles. This work additionally presents a dataset consisting of high-resolution images of 13 micro-PCBs captured in various rotations and perspectives relative to the camera, with each sample labeled for PCB type, rotation category, and perspective categories. Experiments performed and elucidated in this work examine classification accuracy of rotations and perspectives that were not trained on as well as the ability to artificially generate missing rotations and perspectives during training. The results of these experiments include showing that using HVCs is superior to using fully connected layers. This work also showed that certain training samples are more informative of class membership than others. These samples can be identified prior to training by analyzing their position in reduced dimensional space relative to the classes’ centroids in that space. And a definition and calculation both for class density and dataset completeness based on the distribution of data in the reduced dimensional space has been put forth. Experimentation using the dataset completeness calculation shows that those datasets that meet a certain completeness threshold can be trained on a subset of the total dataset, based on each class’s density, while improving upon or maintaining validation accuracy

China: The Next Twenty Years of Reform and Development

China has made some remarkable achievements during the first three decades of economic reform and opening up, rising to become one of the world’s most dynamic and globally-integrated market economies. Yet there remains much unfinished business on the reform and development agenda, coupled with newly emerging challenges. China: The Next Twenty Years of Reform and Development highlights how the deepening of reforms in critical areas such as domestic factor markets, the exchange rate regime and the health system, combined with the strengthening of channels for effective policy implementation, will enable China to cope with the challenges that lie ahead. These include responding to the pending exhaustion of the unlimited supply of labour; playing a constructive role in reducing global trade imbalances; enhancing firms’ ability to innovate; coping with migration, urbanisation and rising inequalities on scales unknown in world history; and dealing with rising energy and metal demand in an era in which low-carbon growth has become a necessity rather than a choice

China: The Next Twenty Years of Reform and Development

China has made some remarkable achievements during the first three decades of economic reform and opening up, rising to become one of the world’s most dynamic and globally-integrated market economies. Yet there remains much unfinished business on the reform and development agenda, coupled with newly emerging challenges. China: The Next Twenty Years of Reform and Development highlights how the deepening of reforms in critical areas such as domestic factor markets, the exchange rate regime and the health system, combined with the strengthening of channels for effective policy implementation, will enable China to cope with the challenges that lie ahead. These include responding to the pending exhaustion of the unlimited supply of labour; playing a constructive role in reducing global trade imbalances; enhancing firms’ ability to innovate; coping with migration, urbanisation and rising inequalities on scales unknown in world history; and dealing with rising energy and metal demand in an era in which low-carbon growth has become a necessity rather than a choice