The growing momentum of instrumenting the Internet of Things (IoT) with advanced machine learning techniques such as deep neural networks (DNNs) faces two practical challenges of limited compute power of edge devices and the need of protecting the confidentiality of the DNNs. The remote inference scheme that executes the DNNs on the server-class or cloud backend can address the above two challenges. However, it brings the concern of leaking the privacy of the IoT devices' users to the curious backend since the user-generated/related data is to be transmitted to the backend. This work develops a lightweight and unobtrusive approach to obfuscate the data before being transmitted to the backend for remote inference. In this approach, the edge device only needs to execute a small-scale neural network, incurring light compute overhead. Moreover, the edge device does not need to inform the backend on whether the data is obfuscated, making the protection unobtrusive. We apply the approach to three case studies of free spoken digit recognition, handwritten digit recognition, and American sign language recognition. The evaluation results obtained from the case studies show that our approach prevents the backend from obtaining the raw forms of the inference data while maintaining the DNN's inference accuracy at the backend.

The assessment of energy expenditure in real life is of great importance for monitoring the current physical state of people, especially in work, sport, elderly care, health care, and everyday life even. This work reports about application of some machine learning methods (linear regression, linear discriminant analysis, k-nearest neighbors, decision tree, random forest, Gaussian naive Bayes, support-vector machine) for monitoring energy expenditures in athletes. The classification problem was to predict the known level of the in-exercise loads (in three categories by calories) by the heart rate activity features measured during the short period of time (1 minute only) after training, i.e by features of the post-exercise load. The results obtained shown that the post-exercise heart activity features preserve the information of the in-exercise training loads and allow us to predict their actual in-exercise levels. The best performance can be obtained by the random forest classifier with all 8 heart rate features (micro-averaged area under curve value AUCmicro = 0.87 and macro-averaged one AUCmacro = 0.88) and the k-nearest neighbors classifier with 4 most important heart rate features (AUCmicro = 0.91 and AUCmacro = 0.89). The limitations and perspectives of the ML methods used are outlined, and some practical advices are proposed as to their improvement and implementation for the better prediction of in-exercise energy expenditures.

The demand for artificial intelligence has grown significantly over the last decade and this growth has been fueled by advances in machine learning techniques and the ability to leverage hardware acceleration. However, in order to increase the quality of predictions and render machine learning solutions feasible for more complex applications, a substantial amount of training data is required. Although small machine learning models can be trained with modest amounts of data, the input for training larger models such as neural networks grows exponentially with the number of parameters. Since the demand for processing training data has outpaced the increase in computation power of computing machinery, there is a need for distributing the machine learning workload across multiple machines, and turning the centralized into a distributed system. These distributed systems present new challenges, first and foremost the efficient parallelization of the training process and the creation of a coherent model. This article provides an extensive overview of the current state-of-the-art in the field by outlining the challenges and opportunities of distributed machine learning over conventional (centralized) machine learning, discussing the techniques used for distributed machine learning, and providing an overview of the systems that are available.

Non-homogeneous hidden Markov models (NHHMM) are a subclass of dependent mixture models used for semi-supervised learning, where both transition probabilities between the latent states and mean parameter of the probability distribution of the responses (for a given state) depend on the set of $p$ covariates. A priori we do not know which (and how) covariates influence the transition probabilities and the mean parameters. This induces a complex combinatorial optimization problem for model selection with $4^p$ potential configurations. To address the problem, in this article we propose an adaptive (A) simulated annealing (SA) expectation maximization (EM) algorithm (ASA-EM) for joint optimization of models and their parameters with respect to a criterion of interest.

Cyanure is an open-source C software package with a Python interface. The goal of Cyanure is to provide state-of-the-art solvers for learning linear models, based on stochastic variance-reduced stochastic optimization with acceleration mechanisms. It provides a simple Python API, which is very close to that of scikit-learn, which should be extended to other languages such as R or Matlab in a near future. Cyanure is distributed under BSD-3-Clause license. Even though this is non-legally binding, the author kindly ask users to cite the present arXiv document in their publications, as well as the publication related to the algorithm they have chosen (see Section 4 for the related publications).

A BSTRACT Knowledge graph embedding research has overlooked the problem of probability calibration. We show popular embedding models are indeed uncalibrated. That means probability estimates associated to predicted triples are unreliable. We present a novel method to calibrate a model when ground truth negatives are not available, which is the usual case in knowledge graphs. We propose to use Platt scaling and isotonic regression alongside our method. Experiments on three datasets with ground truth negatives show our contribution leads to well calibrated models when compared to the gold standard of using negatives. We get significantly better results than the uncalibrated models from all calibration methods. We show isotonic regression offers the best the performance overall, not without tradeoffs. We also show that calibrated models reach state-of-the-art accuracy without the need to define relation-specific decision thresholds. 1 I NTRODUCTION Knowledge graph embedding models are neural architectures that learn vector representations (i.e.

A priori knowledge of melting and boiling could expedite the discovery of pharmaceutical, energetic, and energy harvesting materials. The tools of data science are becoming increasingly important for exploring chemical datasets and predicting material properties. A fundamental part of data-driven modeling is molecular featurization. Herein, we propose a molecular representation with group-constitutive and geometrical descriptors that map to enthalpy and entropy–two thermodynamic quantities that drive phase transitions. The descriptors are inspired by the linear regression-based quantitative structure-property relationship of Yalkowsky and coworkers known as the Unified Physicochemical Property Estimation Relationships (UPPER).

Many real world complex systems can be analyzed through a graph/ network prospective. There are two classical and well-known classes of complex networks, scale-fr ee networks and small world networks, which play a significant role in many domains such as social networks, b iology, cognitive science and signal processing [1, 4, 27, 44]. The human genome is a beautiful example of complex dynamic graph. The genome-wide chromosomal conformation (Hi-C) map represents the spatia l proximity of different parts of genome capturing the genome structure over time [40, 42]. When studying s uch dynamic graphs, one is often required to identify the pattern/couple changes including degree distributio n, path lengths, clustering coefficients, etc, in the graph topology in order to capture the dynamics [25, 33, 41]. The von Neumann entropy of a graph, first introduced by Braunst ein et al. [8], is a spectral measure used in structural pattern recognition. The intuition behind this me asure is linking the graph Laplacian to density matrices from quantum mechanics, and measuring the comp lexity of the graphs in terms of the von Neumman entropy of the corresponding density matrices [32]. In ad dition, the measure can be viewed as the information theoretic Shannon entropy, i.e., S null

Context-aware recommender systems (CARS) have gained increasing attention due to their ability to utilize contextual information. Compared to traditional recommender systems, CARS are, in general, able to generate more accurate recommendations. Latent factors approach accounts for a large proportion of CARS. Recently, a nonlinear Gaussian Process (GP) based factorization method was proven to outperform the state-of-the-art methods in CARS. Despite its effectiveness, GP model-based methods can suffer from over-fitting and may not be able to determine the impact of each context automatically. In order to address such shortcomings, we propose a Gaussian Process Latent V ariable Model Factorization (GPL VMF) method, where we apply an appropriate prior to the original GP model. Our work is primarily inspired by the Gaussian Process Latent V ariable Model (GPL VM), which was a nonlinear dimensionality reduction method. As a result, we improve the performance on the real datasets significantly as well as capturing the importance of each context. In addition to the general advantages, our method provides two main contributions regarding recommender system settings: (1) addressing the influence of bias by setting a nonzero mean function, and (2) utilizing real-valued contexts by fixing the latent space with real values.

The Gumbel-Softmax is a continuous distribution over the simplex that is often used as a relaxation of discrete distributions. Because it can be readily interpreted and easily reparameterized, the Gumbel-Softmax enjoys widespread use. We show that this relaxation experiences two shortcomings that affect its performance, namely: numerical instability caused by its temperature hyperparameter and noisy KL estimates. The first requires the temperature values to be set too high, creating a poor correspondence between continuous components and their respective discrete complements. The second, which is of fundamental importance to variational autoencoders, severely hurts performance. We propose a flexible and reparameterizable family of distributions that circumvents these issues by transforming Gaussian noise into one-hot approximations through an invertible function. Our construction improves numerical stability, and outperforms the Gumbel-Softmax in a variety of experiments while generating samples that are closer to their discrete counterparts and achieving lower-variance gradients. Furthermore, with a careful choice of the invertible function we extend the reparameterization trick to distributions with countably infinite support.