A SVM-based method for face recognition using a wavelet PCA representation

ABSTRACT This paper proposes a new method of fac

Transfer Learning for Domain Adaptation in MRI: Application in Brain Lesion Segmentation

Magnetic Resonance Imaging (MRI) is widely used in routine clinical diagnosis and treatment. However, variations in MRI acquisition protocols result in different appearances of normal and diseased tissue in the images. Convolutional neural networks (CNNs), which have shown to be successful in many medical image analysis tasks, are typically sensitive to the variations in imaging protocols. Therefore, in many cases, networks trained on data acquired with one MRI protocol, do not perform satisfactorily on data acquired with different protocols. This limits the use of models trained with large annotated legacy datasets on a new dataset with a different domain which is often a recurring situation in clinical settings. In this study, we aim to answer the following central questions regarding domain adaptation in medical image analysis: Given a fitted legacy model, 1) How much data from the new domain is required for a decent adaptation of the original network?; and, 2) What portion of the pre-trained model parameters should be retrained given a certain number of the new domain training samples? To address these questions, we conducted extensive experiments in white matter hyperintensity segmentation task. We trained a CNN on legacy MR images of brain and evaluated the performance of the domain-adapted network on the same task with images from a different domain. We then compared the performance of the model to the surrogate scenarios where either the same trained network is used or a new network is trained from scratch on the new dataset.The domain-adapted network tuned only by two training examples achieved a Dice score of 0.63 substantially outperforming a similar network trained on the same set of examples from scratch.Comment: 8 pages, 3 figure

Transcriptional and Cellular Diversity of the Human Heart

Background: The human heart requires a complex ensemble of specialized cell types to perform its essential function. A greater knowledge of the intricate cellular milieu of the heart is critical to increase our understanding of cardiac homeostasis and pathology. As recent advances in low-input RNA sequencing have allowed definitions of cellular transcriptomes at single-cell resolution at scale, we have applied these approaches to assess the cellular and transcriptional diversity of the nonfailing human heart. Methods: Microfluidic encapsulation and barcoding was used to perform single nuclear RNA sequencing with samples from 7 human donors, selected for their absence of overt cardiac disease. Individual nuclear transcriptomes were then clustered based on transcriptional profiles of highly variable genes. These clusters were used as the basis for between-chamber and between-sex differential gene expression analyses and intersection with genetic and pharmacologic data. Results: We sequenced the transcriptomes of 287 269 single cardiac nuclei, revealing 9 major cell types and 20 subclusters of cell types within the human heart. Cellular subclasses include 2 distinct groups of resident macrophages, 4 endothelial subtypes, and 2 fibroblast subsets. Comparisons of cellular transcriptomes by cardiac chamber or sex reveal diversity not only in cardiomyocyte transcriptional programs but also in subtypes involved in extracellular matrix remodeling and vascularization. Using genetic association data, we identified strong enrichment for the role of cell subtypes in cardiac traits and diseases. Intersection of our data set with genes on cardiac clinical testing panels and the druggable genome reveals striking patterns of cellular specificity. Conclusions: Using large-scale single nuclei RNA sequencing, we defined the transcriptional and cellular diversity in the normal human heart. Our identification of discrete cell subtypes and differentially expressed genes within the heart will ultimately facilitate the development of new therapeutics for cardiovascular diseases

Architecture of a Neuroprocessor Chip for Pulse-Coded Neural Networks

We present the architecture of a processor chip to be fabricated in digital VLSI-technology which computes the function of a configurable spiking neuron model. The chip is a submodule of the MASPINN-System (Memory Optimized Accelerator for Spiking Neural Networks). The MASPINN-System is designed as a PCI-accelerator-board for real-time simulation of very complex networks of spiking neurons in the order of 10 6 neurons. Such a performance is desirable for image processing or simulations of brain regions. Within the MASPINN-System, the neuroprocessor chip processes the essential function of a spiking neuron. It models different types of postsynaptic potentials, combines these potentials to a membrane potential and based upon a dynamic threshold, it decides on spike emission. To achieve real-time simulation of very complex spiking neural networks, the architecture emphasizes parallelization in processing and reduction of bandwidth requirements. Keywords: Neuroprocessor, Neuro-Accelerato..

MASPINN: Novel Concepts for a Neuro-Accelerator for Spiking Neural Networks

We present the basic architecture of a Memory Optimized Accelerator for Spiking Neural Networks (MASPINN). The accelerator architecture exploits two novel concepts for an efficient computation of spiking neural networks: weight caching and a compressed memory organization. These concepts allow a further parallelization in processing and reduce bandwidth requirements on accelerator's components. Therefore, they pave the way to dedicated digital hardware for real-time computation of more complex networks of pulse-coded neurons in the order of 10 neurons. The programmable neuron model which the accelerator is based on is described extensively. This shall encourage a discussion and suggestions on features which would be desirable to add to the current model

Simulation of a Digital Neuro-Chip for Spiking Neural Networks

: Conventional hardware platforms are far from reaching real-time simulation requirements of complex spiking neural networks (SNN). Therefore we designed an accelerator board with a neuro-processorchip, called NeuroPipe-Chip. In this paper, we introduce two new concepts on chip-level to speed up the simulation of SNN. The concepts are implemented in the architecture of the NeuroPipe-Chip. We present the hardware structure of the NeuroPipe-Chip, which is modelled on register-transfer-level (RTL) using the hardware description language VHDL. We evaluate the performance of the NeuroPipe-Chip in a system simulation, where the rest of the accelerator board is modelled in behavioral VHDL. For a simple SNN for image segmentation, the NeuroPipe-Chip operating at 100MHz shows an improvement of more than two orders of magnitude compared to an Alpha 500MHz workstation and approaches real-time requirements for SNN in the order of 10 6 neurons. Hence, such an accelerator would allow real-time sim..

Optimal local basis: A reinforcement learning approach for face recognition

This paper presents a novel learning approach for Face Recognition by introducing Optimal Local Basis. Optimal local bases are a set of basis derived by reinforcement learning to represent the face space locally. The reinforcement signal is designed to be correlated to the recognition accuracy. The optimal local bases are derived then by finding the most discriminant features for different parts of the face space, which represents either different individuals or different expressions, orientations, poses, illuminations, and other variants of the same individual. Therefore, unlike most of the existing approaches that solve the recognition problem by using a single basis for all individuals, our proposed method benefits from local information by incorporating different bases for its decision. We also introduce a novel classification scheme that uses reinforcement signal to build a similarity measure in a non-metric space. Experiments on AR, PIE, ORL and YALE databases indicate that the proposed method facilitates robust face recognition under pose, illumination and expression variations. The performance of our method is compared with that of Eigenface, Fisherface, Subclass Discriminant Analysis, and Random Subspace LDA methods as well. © Springer Science+Business Media, LLC 200