671 research outputs found
A Comprehensive Survey of Deep Learning in Remote Sensing: Theories, Tools and Challenges for the Community
In recent years, deep learning (DL), a re-branding of neural networks (NNs),
has risen to the top in numerous areas, namely computer vision (CV), speech
recognition, natural language processing, etc. Whereas remote sensing (RS)
possesses a number of unique challenges, primarily related to sensors and
applications, inevitably RS draws from many of the same theories as CV; e.g.,
statistics, fusion, and machine learning, to name a few. This means that the RS
community should be aware of, if not at the leading edge of, of advancements
like DL. Herein, we provide the most comprehensive survey of state-of-the-art
RS DL research. We also review recent new developments in the DL field that can
be used in DL for RS. Namely, we focus on theories, tools and challenges for
the RS community. Specifically, we focus on unsolved challenges and
opportunities as it relates to (i) inadequate data sets, (ii)
human-understandable solutions for modelling physical phenomena, (iii) Big
Data, (iv) non-traditional heterogeneous data sources, (v) DL architectures and
learning algorithms for spectral, spatial and temporal data, (vi) transfer
learning, (vii) an improved theoretical understanding of DL systems, (viii)
high barriers to entry, and (ix) training and optimizing the DL.Comment: 64 pages, 411 references. To appear in Journal of Applied Remote
Sensin
Deep Learning for Mobile Multimedia: A Survey
Deep Learning (DL) has become a crucial technology for multimedia computing. It offers a powerful instrument to automatically produce high-level abstractions of complex multimedia data, which can be exploited in a number of applications, including object detection and recognition, speech-to- text, media retrieval, multimodal data analysis, and so on. The availability of affordable large-scale parallel processing architectures, and the sharing of effective open-source codes implementing the basic learning algorithms, caused a rapid diffusion of DL methodologies, bringing a number of new technologies and applications that outperform, in most cases, traditional machine learning technologies. In recent years, the possibility of implementing DL technologies on mobile devices has attracted significant attention. Thanks to this technology, portable devices may become smart objects capable of learning and acting. The path toward these exciting future scenarios, however, entangles a number of important research challenges. DL architectures and algorithms are hardly adapted to the storage and computation resources of a mobile device. Therefore, there is a need for new generations of mobile processors and chipsets, small footprint learning and inference algorithms, new models of collaborative and distributed processing, and a number of other fundamental building blocks. This survey reports the state of the art in this exciting research area, looking back to the evolution of neural networks, and arriving to the most recent results in terms of methodologies, technologies, and applications for mobile environments
Distributed learning of CNNs on heterogeneous CPU/GPU architectures
Convolutional Neural Networks (CNNs) have shown to be powerful classification
tools in tasks that range from check reading to medical diagnosis, reaching
close to human perception, and in some cases surpassing it. However, the
problems to solve are becoming larger and more complex, which translates to
larger CNNs, leading to longer training times that not even the adoption of
Graphics Processing Units (GPUs) could keep up to. This problem is partially
solved by using more processing units and distributed training methods that are
offered by several frameworks dedicated to neural network training. However,
these techniques do not take full advantage of the possible parallelization
offered by CNNs and the cooperative use of heterogeneous devices with different
processing capabilities, clock speeds, memory size, among others. This paper
presents a new method for the parallel training of CNNs that can be considered
as a particular instantiation of model parallelism, where only the
convolutional layer is distributed. In fact, the convolutions processed during
training (forward and backward propagation included) represent from -\%
of global processing time. The paper analyzes the influence of network size,
bandwidth, batch size, number of devices, including their processing
capabilities, and other parameters. Results show that this technique is capable
of diminishing the training time without affecting the classification
performance for both CPUs and GPUs. For the CIFAR-10 dataset, using a CNN with
two convolutional layers, and and kernels, respectively, best
speedups achieve using four CPUs and with three GPUs.
Modern imaging datasets, larger and more complex than CIFAR-10 will certainly
require more than -\% of processing time calculating convolutions, and
speedups will tend to increase accordingly
A comprehensive classification of deep learning libraries
Deep Learning (DL) networks are composed of multiple processing layers that learn data representations with multiple levels of abstraction. In recent years, DL networks have significantly improved the state-of-the-art across different domains, including speech processing, text mining, pattern recognition, object detection, robotics and big data analytics. Generally, a researcher or practitioner who is planning to use DL networks for the first time faces difficulties in selecting suitable software tools. The present article provides a comprehensive list and taxonomy of current programming languages and software tools that can be utilized for implementation of DL networks. The motivation of this article is hence to create awareness among researchers, especially beginners, regarding the various languages and interfaces that are available to implement deep learning, and to provide a simplified ontological basis for selecting between them
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