scholarly journals Large-scale deep unsupervised learning using graphics processors

Author(s):  
Rajat Raina ◽  
Anand Madhavan ◽  
Andrew Y. Ng
Author(s):  
Deepak Babu Sam ◽  
Neeraj N Sajjan ◽  
Himanshu Maurya ◽  
R. Venkatesh Babu

We present an unsupervised learning method for dense crowd count estimation. Marred by large variability in appearance of people and extreme overlap in crowds, enumerating people proves to be a difficult task even for humans. This implies creating large-scale annotated crowd data is expensive and directly takes a toll on the performance of existing CNN based counting models on account of small datasets. Motivated by these challenges, we develop Grid Winner-Take-All (GWTA) autoencoder to learn several layers of useful filters from unlabeled crowd images. Our GWTA approach divides a convolution layer spatially into a grid of cells. Within each cell, only the maximally activated neuron is allowed to update the filter. Almost 99.9% of the parameters of the proposed model are trained without any labeled data while the rest 0.1% are tuned with supervision. The model achieves superior results compared to other unsupervised methods and stays reasonably close to the accuracy of supervised baseline. Furthermore, we present comparisons and analyses regarding the quality of learned features across various models.


2018 ◽  
Vol 116 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Lichao Chen ◽  
Sudhir Singh ◽  
Thomas Kailath ◽  
Vwani Roychowdhury

Despite significant recent progress, machine vision systems lag considerably behind their biological counterparts in performance, scalability, and robustness. A distinctive hallmark of the brain is its ability to automatically discover and model objects, at multiscale resolutions, from repeated exposures to unlabeled contextual data and then to be able to robustly detect the learned objects under various nonideal circumstances, such as partial occlusion and different view angles. Replication of such capabilities in a machine would require three key ingredients: (i) access to large-scale perceptual data of the kind that humans experience, (ii) flexible representations of objects, and (iii) an efficient unsupervised learning algorithm. The Internet fortunately provides unprecedented access to vast amounts of visual data. This paper leverages the availability of such data to develop a scalable framework for unsupervised learning of object prototypes—brain-inspired flexible, scale, and shift invariant representations of deformable objects (e.g., humans, motorcycles, cars, airplanes) comprised of parts, their different configurations and views, and their spatial relationships. Computationally, the object prototypes are represented as geometric associative networks using probabilistic constructs such as Markov random fields. We apply our framework to various datasets and show that our approach is computationally scalable and can construct accurate and operational part-aware object models much more efficiently than in much of the recent computer vision literature. We also present efficient algorithms for detection and localization in new scenes of objects and their partial views.


2012 ◽  
Vol 98 ◽  
pp. 114-122
Author(s):  
Hong Gu ◽  
Guangzhou Zhao ◽  
Jianliang Zhang

2021 ◽  
Author(s):  
Petros Barmpas ◽  
Sotiris Tasoulis ◽  
Aristidis G. Vrahatis ◽  
Panagiotis Anagnostou ◽  
Spiros Georgakopoulos ◽  
...  

1AbstractRecent technological advancements in various domains, such as the biomedical and health, offer a plethora of big data for analysis. Part of this data pool is the experimental studies that record various and several features for each instance. It creates datasets having very high dimensionality with mixed data types, with both numerical and categorical variables. On the other hand, unsupervised learning has shown to be able to assist in high-dimensional data, allowing the discovery of unknown patterns through clustering, visualization, dimensionality reduction, and in some cases, their combination. This work highlights unsupervised learning methodologies for large-scale, high-dimensional data, providing the potential of a unified framework that combines the knowledge retrieved from clustering and visualization. The main purpose is to uncover hidden patterns in a high-dimensional mixed dataset, which we achieve through our application in a complex, real-world dataset. The experimental analysis indicates the existence of notable information exposing the usefulness of the utilized methodological framework for similar high-dimensional and mixed, real-world applications.


Author(s):  
Mian Lu ◽  
Qiong Luo

Large-scale Genome-Wide Association Studies (GWAS) are a Big Data application due to the great amount of data to process and high computation intensity. Furthermore, numerical issues (e.g., floating point underflow) limit the data scale in some applications. Graphics Processors (GPUs) have been used to accelerate genomic data analytics, such as sequence alignment, single-Nucleotide Polymorphism (SNP) detection, and Minor Allele Frequency (MAF) computation. As MAF computation is the most time-consuming task in GWAS, the authors discuss in detail their techniques of accelerating this task using the GPU. They first present a reduction-based algorithm that better matches the GPU’s data-parallelism feature than the original algorithm implemented in the CPU-based tool. Then they implement this algorithm on the GPU efficiently by carefully optimizing local memory utilization and avoiding user-level synchronization. As the MAF computation suffers from floating point underflow, the authors transform the computation to logarithm space. In addition to the MAF computation, they briefly introduce the GPU-accelerated sequence alignment and SNP detection. The experimental results show that the GPU-based GWAS implementations can accelerate state-of-the-art CPU-based tools by up to an order of magnitude.


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