Deep Learning
Social Behavioral Phenotyping of Drosophila with a2D-3D Hybrid CNN Framework
Jiang, Ziping, Chazot, Paul L., Celebi, M. Emre, Crookes, Danny, Jiang, Richard
However, such pipelines are not Drosophila Melanogaster, also known as fruit flies, can transferable since they are highly dependent on the tracking exhibit a wide range of complex social behaviors though it system, which is often designed for a particular task with has only 105 neurons. It also has a high frequency of social specific inputs and outputs.
Recurrent Neural Networks For Accurate RSSI Indoor Localization
Hoang, Minh Tu, Yuen, Brosnan, Dong, Xiaodai, Lu, Tao, Westendorp, Robert, Reddy, Kishore
This paper proposes recurrent neuron networks (RNNs) for a fingerprinting indoor localization using WiFi. Instead of locating user's position one at a time as in the cases of conventional algorithms, our RNN solution aims at trajectory positioning and takes into account the relation among the received signal strength indicator (RSSI) measurements in a trajectory. Furthermore, a weighted average filter is proposed for both input RSSI data and sequential output locations to enhance the accuracy among the temporal fluctuations of RSSI. The results using different types of RNN including vanilla RNN, long short-term memory (LSTM), gated recurrent unit (GRU) and bidirectional LSTM (BiLSTM) are presented. On-site experiments demonstrate that the proposed structure achieves an average localization error of $0.75$ m with $80\%$ of the errors under $1$ m, which outperforms the conventional KNN algorithms and probabilistic algorithms by approximately $30\%$ under the same test environment.
Symbolic Regression for Constructing Analytic Models in Reinforcement Learning
Derner, Erik, Kubalík, Jiří, Ancona, Nicola, Babuška, Robert
Reinforcement learning (RL) is a widely used approach for controlling systems with unknown or time-varying dynamics. Even though RL does not require a model of the system, it is known to be faster and safer when using models learned online. We propose to employ symbolic regression (SR) to construct parsimonious process models described by analytic equations for real-time RL control. We have tested our method with two different state-of-the-art SR algorithms which automatically search for equations that fit the measured data. In addition to the standard problem formulation in the state-space domain, we show how the method can also be applied to input-output models of the NARX (nonlinear autoregressive with exogenous input) type. We present the approach on three simulated examples with up to 14-dimensional state space: an inverted pendulum, a mobile robot, and a biped walking robot. A comparison with deep neural networks and local linear regression shows that SR in most cases outperforms these commonly used alternative methods. We demonstrate on a real pendulum system that the analytic model found enables RL to successfully perform the swing-up task, based on a model constructed from only 100 data samples.
A Sober Look at Neural Network Initializations
Improving and understanding the training phase of deep neural networks has attracted a lot of attention in the last couple of years. This training phase mostly consists of minimizing an empirical risk term, and due to the structure of deep neural networks, the corresponding optimization landscape is convoluted and highly non-convex. To avoid getting stuck in local minima several variants of stochastic gradient descent have been proposed and successfully applied. These success stories suggest that the initialization of neural networks, that is, choosing the starting point of the optimization, has become less important. In fact, the two commonly used heuristics proposed in [7, 9] both focus on normalizing the variance of the weights of the neural network to ensure that the gradients of deep networks do not exponentially explode or implode. So far, however, positive or negative side-effects of these initialization strategies have not been investigated in depth. This is the first goal of our paper, and the second goal is to use these insights to develop a new initialization strategy. To be a bit more specific let ·: R [0,) be the ReLU function, that is t: max{0, t}.
Sensing Social Media Signals for Cryptocurrency News
Beck, Johannes, Huang, Roberta, Lindner, David, Guo, Tian, Zhang, Ce, Helbing, Dirk, Antulov-Fantulin, Nino
The ability to track and monitor relevant and important news in real-time is of crucial interest in multiple industrial sectors. In this work, we focus on the set of cryptocurrency news, which recently became of emerging interest to the general and financial audience. In order to track relevant news in real-time, we (i) match news from the web with tweets from social media, (ii) track their intraday tweet activity and (iii) explore different machine learning models for predicting the number of the article mentions on Twitter within the first 24 hours after its publication. We compare several machine learning models, such as linear extrapolation, linear and random forest autoregressive models, and a sequence-to-sequence neural network. We find that the random forest autoregressive model behaves comparably to more complex models in the majority of tasks.
Hierarchical Attention Generative Adversarial Networks for Cross-domain Sentiment Classification
Zhang, Yuebing, Miao, Duoqian, Wang, Jiaqi
Cross-domain sentiment classification (CDSC) is an importance task in domain adaptation and sentiment classification. Due to the domain discrepancy, a sentiment classifier trained on source domain data may not works well on target domain data. In recent years, many researchers have used deep neural network models for cross-domain sentiment classification task, many of which use Gradient Reversal Layer (GRL) to design an adversarial network structure to train a domain-shared sentiment classifier. Different from those methods, we proposed Hierarchical Attention Generative Adversarial Networks (HAGAN) which alternately trains a generator and a discriminator in order to produce a document representation which is sentiment-distinguishable but domain-indistinguishable. Besides, the HAGAN model applies Bidirectional Gated Recurrent Unit (Bi-GRU) to encode the contextual information of a word and a sentence into the document representation. In addition, the HAGAN model use hierarchical attention mechanism to optimize the document representation and automatically capture the pivots and non-pivots. The experiments on Amazon review dataset show the effectiveness of HAGAN.
Attention-based Convolutional Neural Network for Weakly Labeled Human Activities Recognition with Wearable Sensors
Wang, Kun, He, Jun, Zhang, Lei
Unlike images or videos data which can be easily labeled by human being, sensor data annotation is a time-consuming process. However, traditional methods of human activity recognition require a large amount of such strictly labeled data for training classifiers. In this paper, we present an attention-based convolutional neural network for human recognition from weakly labeled data. The proposed attention model can focus on labeled activity among a long sequence of sensor data, and while filter out a large amount of background noise signals. In experiment on the weakly labeled dataset, we show that our attention model outperforms classical deep learning methods in accuracy. Besides, we determine the specific locations of the labeled activity in a long sequence of weakly labeled data by converting the compatibility score which is generated from attention model to compatibility density. Our method greatly facilitates the process of sensor data annotation, and makes data collection more easy.
Machines listening to music: the role of signal representations in learning from music
Bammer, Roswitha, Breger, Anna, Dörfler, Monika, Harar, Pavol, Smekal, Zdenek
Recent, extremely successful methods in deep learning, such as convolutional neural networks (CNNs) have originated in machine learning for images. When applied to music signals and related music information retrieval (MIR) problems, researchers often apply standard FFT-based signal processing methods in order to create an image from the raw audio data. The impact of this basic signal processing step on the final outcome of the MIR task has not been widely studied and is not well understood. In this contribution, we study Gabor Scattering and a new representation, namely Mel Scattering. Furthermore, we suggest an alternative enhancement of the loss function that uses transformed representations of the output data to incorporate additional available information. We show how applying various different signal analysis methods can lead to useful invariances and improve the overall performance in MIR problems by reducing the amount of necessary training data or the necessity of augmentation.
Optimization of Inf-Convolution Regularized Nonconvex Composite Problems
Laude, Emanuel, Wu, Tao, Cremers, Daniel
In this work, we consider nonconvex composite problems that involve inf-convolution with a Legendre function, which gives rise to an anisotropic generalization of the proximal mapping and Moreau-envelope. In a convex setting such problems can be solved via alternating minimization of a splitting formulation, where the consensus constraint is penalized with a Legendre function. In contrast, for nonconvex models it is in general unclear that this approach yields stationary points to the infimal convolution problem. To this end we analytically investigate local regularity properties of the Moreau-envelope function under prox-regularity, which allows us to establish the equivalence between stationary points of the splitting model and the original inf-convolution model. We apply our theory to characterize stationary points of the penalty objective, which is minimized by the elastic averaging SGD (EASGD) method for distributed training. Numerically, we demonstrate the practical relevance of the proposed approach on the important task of distributed training of deep neural networks.
Visualization and Interpretation of Latent Spaces for Controlling Expressive Speech Synthesis through Audio Analysis
Tits, Noé, Wang, Fengna, Haddad, Kevin El, Pagel, Vincent, Dutoit, Thierry
The field of Text-to-Speech has experienced huge improvements last years benefiting from deep learning techniques. Producing realistic speech becomes possible now. As a consequence, the research on the control of the expressiveness, allowing to generate speech in different styles or manners, has attracted increasing attention lately. Systems able to control style have been developed and show impressive results. However the control parameters often consist of latent variables and remain complex to interpret. In this paper, we analyze and compare different latent spaces and obtain an interpretation of their influence on expressive speech. This will enable the possibility to build controllable speech synthesis systems with an understandable behaviour.