Online Social Networks have become an important medium for communication among people who suffer from mental disorders to share moments of hardship and to seek support. Here we analyze how Reddit discussions can help improve the health conditions of its users. Using emotional tone of user publications as a proxy for his emotional state, we uncover relationships between state changes and interactions he has in a given community. We observe that authors of negative posts often write more positive comments after engaging in discussions. Second, we build models based on state-of-the-art embedding techniques and RNNs to predict shifts in emotional tone. We show that it is possible to predict with good accuracy the reaction of users of mental disorder online communities to the interactions experienced in these platforms. Our models could assist in interventions promoted by health care professionals to provide support to people suffering from mental health illnesses.

Boosting is an ensemble method that combines base models in a sequential manner to achieve high predictive accuracy. A popular learning algorithm based on this ensemble method is eXtreme Gradient Boosting (XGB). We present an adaptation of XGB for classification of evolving data streams. In this setting, new data arrives over time and the relationship between the class and the features may change in the process, thus exhibiting concept drift. The proposed method creates new members of the ensemble from mini-batches of data as new data becomes available. The maximum ensemble size is fixed, but learning does not stop when this size is reached because the ensemble is updated on new data to ensure consistency with the current concept. We also explore the use of concept drift detection to trigger a mechanism to update the ensemble. We test our method on real and synthetic data with concept drift and compare it against batch-incremental and instance-incremental classification methods for data streams.

Large neural network models have been successful in learning functions of importance in many branches of science, including physics, chemistry and biology. Recent theoretical work has shown explicit learning bounds for wide networks and kernel methods on some simple classes of functions, but not on more complex functions which arise in practice. We extend these techniques to provide learning bounds for analytic functions on the sphere for any kernel method or equivalent infinitely-wide network with the corresponding activation function trained with SGD. We show that a wide, one-hidden layer ReLU network can learn analytic functions with a number of samples proportional to the derivative of a related function. Many functions important in the sciences are therefore efficiently learnable. As an example, we prove explicit bounds on learning the many-body gravitational force function given by Newton's law of gravitation. Our theoretical bounds suggest that very wide ReLU networks (and the corresponding NTK kernel) are better at learning analytic functions as compared to kernel learning with Gaussian kernels. We present experimental evidence that the many-body gravitational force function is easier to learn with ReLU networks as compared to networks with exponential activations.

Traditional distributed deep reinforcement learning (RL) commonly relies on exchanging the experience replay memory (RM) of each agent. Since the RM contains all state observations and action policy history, it may incur huge communication overhead while violating the privacy of each agent. Alternatively, this article presents a communication-efficient and privacy-preserving distributed RL framework, coined federated reinforcement distillation (FRD). In FRD, each agent exchanges its proxy experience replay memory (ProxRM), in which policies are locally averaged with respect to proxy states clustering actual states. To provide FRD design insights, we present ablation studies on the impact of ProxRM structures, neural network architectures, and communication intervals. Furthermore, we propose an improved version of FRD, coined mixup augmented FRD (MixFRD), in which ProxRM is interpolated using the mixup data augmentation algorithm. Simulations in a Cartpole environment validate the effectiveness of MixFRD in reducing the variance of mission completion time and communication cost, compared to the benchmark schemes, vanilla FRD, federated reinforcement learning (FRL), and policy distillation (PD).

The graph represents a network of 4,023 Twitter users whose tweets in the requested range contained "(Artificial Intelligence) OR #AI", or who were replied to or mentioned in those tweets. The network was obtained from the NodeXL Graph Server on Thursday, 14 May 2020 at 04:33 UTC. The requested start date was Thursday, 14 May 2020 at 00:01 UTC and the maximum number of days (going backward) was 14. The maximum number of tweets collected was 5,000. The tweets in the network were tweeted over the 1-day, 1-hour, 46-minute period from Tuesday, 12 May 2020 at 04:35 UTC to Wednesday, 13 May 2020 at 06:22 UTC.

Perhaps even, the largest tech revolution we've yet to experience especially in the world of finance. Financial services companies require detailed, accurate information to make informed decisions and offer valuable products to their customers. High-quality data helps ensure that financial decisions are made soundly, quickly, and with a reduced amount of risk. Investment in AI is rapidly growing as financial services organizations continue to see the value it offers. At the enterprise level, several trends prevent organizations with new opportunities to disrupt traditional business models.

UK GDP fell by 2 per cent in the first quarter of 2020, the most rapid contraction of the UK's economy since the 2008 financial crisis. Rishi Sunak, the chancellor of the exchequer, said, "It is now very likely that the UK economy will face a significant recession this year, and we're already in the middle of that as we speak." The Bank of England predicts that the UK economy could shrink by as much as 14 per cent in 2020. In England some people who aren't able to work from home returned to work today, as part of the government's recent easing of certain restrictions. Despite the government urging people to avoid public transport if they could, some commuters said buses and trains were too crowded to practice social distancing. It could be as long as "four or five years" before covid-19 is under control and the pandemic could "potentially get worse", according to the World Health Organization's chief scientist Soumya Swaminathan. Speaking at an FT conference, she said a vaccine "seems ...

Recommendation systems have lately been popularized globally, with primary use cases in online interaction systems, with significant focus on e-commerce platforms. We have developed a machine learning-based recommendation platform, which can be easily applied to almost any items and/or actions domain. Contrary to existing recommendation systems, our platform supports multiple types of interaction data with multiple modalities of metadata natively. This is achieved through multi-modal fusion of various data representations. We deployed the platform into multiple e-commerce stores of different kinds, e.g. food and beverages, shoes, fashion items, telecom operators. Here, we present our system, its flexibility and performance. We also show benchmark results on open datasets, that significantly outperform state-of-the-art prior work.

Variational Bayesian inference is an important machine-learning tool that finds application from statistics to robotics. The goal is to find an approximate probability density function (PDF) from a chosen family that is in some sense `closest' to the full Bayesian posterior. Closeness is typically defined through the selection of an appropriate loss functional such as the Kullback-Leibler (KL) divergence. In this paper, we explore a new formulation of variational inference by exploiting the fact that the set of PDFs constitutes a Bayesian Hilbert space under careful definitions of vector addition, scalar multiplication and an inner product. We show that variational inference based on KL divergence then amounts to an iterative projection of the Bayesian posterior onto a subspace corresponding to the selected approximation family. In fact, the inner product chosen for the Bayesian Hilbert space suggests the definition of a new measure of the information contained in a PDF and in turn a new divergence is introduced. Each step in the iterative projection is equivalent to a local minimization of this divergence. We present an example Bayesian subspace based on exponentiated Hermite polynomials as well as work through the details of this general framework for the specific case of the multivariate Gaussian approximation family and show the equivalence to another Gaussian variational inference approach. We furthermore discuss the implications for systems that exhibit sparsity, which is handled naturally in Bayesian space.

This is fomenting the development of comprehensive modelling The COVID-19 pandemic has highlighted the importance and simulation to support the design of health interventions of in-silico epidemiological modelling in predicting and policies, and to guide decision-making in a variety of the dynamics of infectious diseases to inform health system domains [22, 49]. For example, simulations health policy and decision makers about suitable prevention have provided valuable insight to deal with public health and containment strategies. Work in this setting problems such as tobacco consumption in New Zealand [50], involves solving challenging inference and control and diabetes and obesity in the US [58]. They have been problems in individual-based models of ever increasing used to explore policy options such as those in maternal and complexity. Here we discuss recent breakthroughs antenatal care in Uganda [44], and applied to evaluate health in machine learning, specifically in simulation-based reform scenarios such as predicting changes in access to inference, and explore its potential as a novel venue primary care services in Portugal [21]. Their applicability for model calibration to support the design and evaluation in informing the design of cancer screening programmes of public health interventions. To further stimulate has been also discussed [42, 23]. Recently, simulations have research, we are developing software interfaces that informed the response to the COVID-19 outbreak [19].