Deep Learning
Book Review: Architects of Intelligence
Artificial intelligence seems to be the go-to solution to every problem there is (technological in nature or otherwise), and it's only getting worse. A staggering number of both startups and established companies are loudly proclaiming how AI, or machine learning, or deep learning, or whatever is absolutely going to make everything faster, better, cheaper, fairer, and so on. The reason that this sort of breathless and inevitably shallow media-driven enthusiasm for artificial intelligence is effective is because there's just enough of a general understanding of AI for people to know that it can do some cool things, but not so much of an understanding for people to question what it's actually capable of, or whether applying to to a specific problem is a good idea. This is not to say that a lack of understanding is anyone's fault, really: it's hard to define what AI even is, much less communicate how it works. And without the proper context, there's no way to make an informed judgement about the future potential of artificial intelligence.
The Difference Between Artificial Intelligence, Machine Learning, and Deep Learning
Artificial Intelligence (AI) has entered our daily lives with a bang. From marketing to medicine, every business and industry seems to be affected. Technology companies are competing for dominance in the race to lead the market and acquire the most innovative and promising AI businesses. You may already be using AI in everyday life, with applications such as speech recognition, virtual assistance on your smartphone, the recommendation algorithms of shopping websites and music or video streaming services, or even when you visit the doctor and he compares an X-Ray or other medical images with other medical data. And then there are the terms machine learning and deep learning, which seem to confuse many people.
Deep autoregressive neural networks for high-dimensional inverse problems in groundwater contaminant source identification
Mo, Shaoxing, Zabaras, Nicholas, Shi, Xiaoqing, Wu, Jichun
Identification of a groundwater contaminant source simultaneously with the hydraulic conductivity in highly-heterogeneous media often results in a high-dimensional inverse problem. In this study, a deep autoregressive neural network-based surrogate method is developed for the forward model to allow us to solve efficiently such high-dimensional inverse problems. The surrogate is trained using limited evaluations of the forward model. Since the relationship between the time-varying inputs and outputs of the forward transport model is complex, we propose an autoregressive strategy, which treats the output at the previous time step as input to the network for predicting the output at the current time step. We employ a dense convolutional encoder-decoder network architecture in which the high-dimensional input and output fields of the model are treated as images to leverage the robust capability of convolutional networks in image-like data processing. An iterative local updating ensemble smoother (ILUES) algorithm is used as the inversion framework. The proposed method is evaluated using a synthetic contaminant source identification problem with 686 uncertain input parameters. Results indicate that, with relatively limited training data, the deep autoregressive neural network consisting of 27 convolutional layers is capable of providing an accurate approximation for the high-dimensional model input-output relationship. The autoregressive strategy substantially improves the network's accuracy and computational efficiency. The application of the surrogate-based ILUES in solving the inverse problem shows that it can achieve accurate inversion results and predictive uncertainty estimates.
A Multiscale Image Denoising Algorithm Based On Dilated Residual Convolution Network
Liu, Chang, Shang, Zhaowei, Qin, Anyong
Image denoising is a classical problem in low level computer vision. Model-based optimization methods and deep learning approaches have been the two main strategies for solving the problem. Model-based optimization methods are flexible for handling different inverse problems but are usually time-consuming. In contrast, deep learning methods have fast testing speed but the performance of these CNNs is still inferior. To address this issue, here we propose a novel deep residual learning model that combines the dilated residual convolution and multi-scale convolution groups. Due to the complex patterns and structures of inside an image, the multiscale convolution group is utilized to learn those patterns and enlarge the receptive field. Specifically, the residual connection and batch normalization are utilized to speed up the training process and maintain the denoising performance. In order to decrease the gridding artifacts, we integrate the hybrid dilated convolution design into our model. To this end, this paper aims to train a lightweight and effective denoiser based on multiscale convolution group. Experimental results have demonstrated that the enhanced denoiser can not only achieve promising denoising results, but also become a strong competitor in practical application.
Utilizing Neural Networks and Linguistic Metadata for Early Detection of Depression Indications in Text Sequences
Trotzek, Marcel, Koitka, Sven, Friedrich, Christoph M.
Depression is ranked as the largest contributor to global disability and is also a major reason for suicide. Still, many individuals suffering from forms of depression are not treated for various reasons. Previous studies have shown that depression also has an effect on language usage and that many depressed individuals use social media platforms or the internet in general to get information or discuss their problems. This paper addresses the early detection of depression using machine learning models based on messages on a social platform. In particular, a convolutional neural network based on different word embeddings is evaluated and compared to a classification based on user-level linguistic metadata. An ensemble of both approaches is shown to achieve state-of-the-art results in a current early detection task. Furthermore, the currently popular ERDE score as metric for early detection systems is examined in detail and its drawbacks in the context of shared tasks are illustrated. A slightly modified metric is proposed and compared to the original score. Finally, a new word embedding was trained on a large corpus of the same domain as the described task and is evaluated as well.
Machine learning and AI research for Patient Benefit: 20 Critical Questions on Transparency, Replicability, Ethics and Effectiveness
Vollmer, Sebastian, Mateen, Bilal A., Bohner, Gergo, Kirรกly, Franz J, Ghani, Rayid, Jonsson, Pall, Cumbers, Sarah, Jonas, Adrian, McAllister, Katherine S. L., Myles, Puja, Granger, David, Birse, Mark, Branson, Richard, Moons, Karel GM, Collins, Gary S, Ioannidis, John P. A., Holmes, Chris, Hemingway, Harry
Machine learning (ML), artificial intelligence (AI) and other modern statistical methods are providing new opportunities to operationalize previously untapped and rapidly growing sources of data for patient benefit. Whilst there is a lot of promising research currently being undertaken, the literature as a whole lacks: transparency; clear reporting to facilitate replicability; exploration for potential ethical concerns; and, clear demonstrations of effectiveness. There are many reasons for why these issues exist, but one of the most important that we provide a preliminary solution for here is the current lack of ML/AI- specific best practice guidance. Although there is no consensus on what best practice looks in this field, we believe that interdisciplinary groups pursuing research and impact projects in the ML/AI for health domain would benefit from answering a series of questions based on the important issues that exist when undertaking work of this nature. Here we present 20 questions that span the entire project life cycle, from inception, data analysis, and model evaluation, to implementation, as a means to facilitate project planning and post-hoc (structured) independent evaluation. By beginning to answer these questions in different settings, we can start to understand what constitutes a good answer, and we expect that the resulting discussion will be central to developing an international consensus framework for transparent, replicable, ethical and effective research in artificial intelligence (AI-TREE) for health.
Image Embedding of PMU Data for Deep Learning towards Transient Disturbance Classification
Zhu, Yongli, Liu, Chengxi, Sun, Kai
This paper presents a study on power grid disturbance classification by Deep Learning (DL). A real synchrophasor set composing of three different types of disturbance events from the Frequency Monitoring Network (FNET) is used. An image embedding technique called Gramian Angular Field is applied to transform each time series of event data to a two-dimensional image for learning. Two main DL algorithms, i.e. CNN (Convolutional Neural Network) and RNN (Recurrent Neural Network) are tested and compared with two widely used data mining tools, the Support Vector Machine and Decision Tree. The test results demonstrate the superiority of the both DL algorithms over other methods in the application of power system transient disturbance classification.
Multimodal Sensor Fusion In Single Thermal image Super-Resolution
Almasri, Feras, Debeir, Olivier
With the fast growth in the visual surveillance and security sectors, thermal infrared images have become increasingly necessary in a large variety of industrial applications. This is true even though IR sensors are still more expensive than their RGB counterpart having the same resolution. In this paper, we propose a deep learning solution to enhance the thermal image resolution. The following results are given: (I) Introduction of a multimodal, visual-thermal fusion model that addresses thermalimage super-resolution, via integrating high-frequency information from the visual image.
Nonparametric Feature Extraction from Dendrograms
Chehreghani, Morteza Haghir, Chehreghani, Mostafa Haghir
We study nonparametric feature extraction from hierarchies. The commonly used Minimax distance measures correspond to building a dendrogram with single linkage criterion, with the definition of specific forms of a level function and a distance function over that. Therefore, we develop a generalized framework wherein different distance measures can be inferred from different types of dendrograms, level functions and distance functions. Via an appropriate embedding, we compute a vector-based representation of the inferred distances, in order to enable many numerical machine learning algorithms to employ such distances. Then, we study the aggregation of different dendrogram-based distances respectively in solution space and in representation space in the spirit of deep learning models. Finally, we demonstrate the effectiveness of our approach via numerical studies.
Dreaming neural networks: rigorous results
Agliari, Elena, Alemanno, Francesco, Barra, Adriano, Fachechi, Alberto
Recently a daily routine for associative neural networks has been proposed: the network Hebbian-learns during the awake state (thus behaving as a standard Hopfield model), then, during its sleep state, optimizing information storage, it consolidates pure patterns and removes spurious ones: this forces the synaptic matrix to collapse to the projector one (ultimately approaching the Kanter-Sompolinksy model). This procedure keeps the learning Hebbian-based (a biological must) but, by taking advantage of a (properly stylized) sleep phase, still reaches the maximal critical capacity (for symmetric interactions). So far this emerging picture (as well as the bulk of papers on unlearning techniques) was supported solely by mathematically-challenging routes, e.g. mainly replica-trick analysis and numerical simulations: here we rely extensively on Guerra's interpolation techniques developed for neural networks and, in particular, we extend the generalized stochastic stability approach to the case. Confining our description within the replica symmetric approximation (where the previous ones lie), the picture painted regarding this generalization (and the previously existing variations on theme) is here entirely confirmed. Further, still relying on Guerra's schemes, we develop a systematic fluctuation analysis to check where ergodicity is broken (an analysis entirely absent in previous investigations). We find that, as long as the network is awake, ergodicity is bounded by the Amit-Gutfreund-Sompolinsky critical line (as it should), but, as the network sleeps, sleeping destroys spin glass states by extending both the retrieval as well as the ergodic region: after an entire sleeping session the solely surviving regions are retrieval and ergodic ones and this allows the network to achieve the perfect retrieval regime (the number of storable patterns equals the number of neurons in the network).