Genre
An unsupervised bayesian approach for the joint reconstruction and classification of cutaneous reflectance confocal microscopy images
Halimi, Abdelghafour, Batatia, Hadj, Digabel, Jimmy Le, Josse, Gwendal, Tourneret, Jean-Yves
This paper studies a new Bayesian algorithm for the joint reconstruction and classification of reflectance confocal microscopy (RCM) images, with application to the identification of human skin lentigo. The proposed Bayesian approach takes advantage of the distribution of the multiplicative speckle noise affecting the true reflectivity of these images and of appropriate priors for the unknown model parameters. A Markov chain Monte Carlo (MCMC) algorithm is proposed to jointly estimate the model parameters and the image of true reflectivity while classifying images according to the distribution of their reflectivity. Precisely, a Metropolis-within-Gibbs sampler is investigated to sample the posterior distribution of the Bayesian model associated with RCM images and to build estimators of its parameters, including labels indicating the class of each RCM image. The resulting algorithm is applied to synthetic data and to real images from a clinical study containing healthy and lentigo patients. The lentigo is a hyperplasia that affects the skin.
Recurrent Poisson Factorization for Temporal Recommendation
Hosseini, Seyed Abbas, Alizadeh, Keivan, Khodadadi, Ali, Arabzadeh, Ali, Farajtabar, Mehrdad, Zha, Hongyuan, Rabiee, Hamid R.
Poisson factorization is a probabilistic model of users and items for recommendation systems, where the so-called implicit consumer data is modeled by a factorized Poisson distribution. There are many variants of Poisson factorization methods who show state-of-the-art performance on real-world recommendation tasks. However, most of them do not explicitly take into account the temporal behavior and the recurrent activities of users which is essential to recommend the right item to the right user at the right time. In this paper, we introduce Recurrent Poisson Factorization (RPF) framework that generalizes the classical PF methods by utilizing a Poisson process for modeling the implicit feedback. RPF treats time as a natural constituent of the model and brings to the table a rich family of time-sensitive factorization models. To elaborate, we instantiate several variants of RPF who are capable of handling dynamic user preferences and item specification (DRPF), modeling the social-aspect of product adoption (SRPF), and capturing the consumption heterogeneity among users and items (HRPF). We also develop a variational algorithm for approximate posterior inference that scales up to massive data sets. Furthermore, we demonstrate RPF's superior performance over many state-of-the-art methods on synthetic dataset, and large scale real-world datasets on music streaming logs, and user-item interactions in M-Commerce platforms.
Variational Lossy Autoencoder
Chen, Xi, Kingma, Diederik P., Salimans, Tim, Duan, Yan, Dhariwal, Prafulla, Schulman, John, Sutskever, Ilya, Abbeel, Pieter
Representation learning seeks to expose certain aspects of observed data in a learned representation that's amenable to downstream tasks like classification. For instance, a good representation for 2D images might be one that describes only global structure and discards information about detailed texture. In this paper, we present a simple but principled method to learn such global representations by combining Variational Autoencoder (VAE) with neural autoregressive models such as RNN, MADE and PixelRNN/CNN. Our proposed VAE model allows us to have control over what the global latent code can learn and , by designing the architecture accordingly, we can force the global latent code to discard irrelevant information such as texture in 2D images, and hence the VAE only "autoencodes" data in a lossy fashion. In addition, by leveraging autoregressive models as both prior distribution $p(z)$ and decoding distribution $p(x|z)$, we can greatly improve generative modeling performance of VAEs, achieving new state-of-the-art results on MNIST, OMNIGLOT and Caltech-101 Silhouettes density estimation tasks.
Sequential Quantiles via Hermite Series Density Estimation
Stephanou, Michael, Varughese, Melvin, Macdonald, Iain
Sequential quantile estimation refers to incorporating observations into quantile estimates in an incremental fashion thus furnishing an online estimate of one or more quantiles at any given point in time. Sequential quantile estimation is also known as online quantile estimation. This area is relevant to the analysis of data streams and to the one-pass analysis of massive data sets. Applications include network traffic and latency analysis, real time fraud detection and high frequency trading. We introduce new techniques for online quantile estimation based on Hermite series estimators in the settings of static quantile estimation and dynamic quantile estimation. In the static quantile estimation setting we apply the existing Gauss-Hermite expansion in a novel manner. In particular, we exploit the fact that Gauss-Hermite coefficients can be updated in a sequential manner. To treat dynamic quantile estimation we introduce a novel expansion with an exponentially weighted estimator for the Gauss-Hermite coefficients which we term the Exponentially Weighted Gauss-Hermite (EWGH) expansion. These algorithms go beyond existing sequential quantile estimation algorithms in that they allow arbitrary quantiles (as opposed to pre-specified quantiles) to be estimated at any point in time. In doing so we provide a solution to online distribution function and online quantile function estimation on data streams. In particular we derive an analytical expression for the CDF and prove consistency results for the CDF under certain conditions. In addition we analyse the associated quantile estimator. Simulation studies and tests on real data reveal the Gauss-Hermite based algorithms to be competitive with a leading existing algorithm.
Flipboard on Flipboard
From helping you take care of email to creating personalized online shopping experiences, AI promises to transform the way we live and work. But with all the hype out there, how do we know which benefits we'll actually see? What is the top benefit you predict emerging from AI, and do you think the overall benefits will live up to the hype? The greatest benefit of AI -- which is already emerging -- is the elimination of repetitive tasks. From chat bots that can free up human staffers' times to work on more complex issues, to scheduling AIs like x.ai that eliminate the need to schedule meetings, AI will ultimately help humans spend more time focusing on creative and high-mental-effort activities.
'The Legend Of Zelda: Breath Of The Wild' Guides, Tips And Cheats For Nintendo Switch, Wii U
The Legend Of Zelda: Breath Of The Wild is being played by gamers everywhere, and our partners at iDigitalTimes have been working hard discovering every inch of 2017's incarnation of Hyrule. The Legend Of Zelda: Breath Of The Wild is shaping up to be a once-in-a-lifetime game, and we're happy you've chosen us to kick off your celebration. For even more on this epic, sprawling adventure, be sure to read the iDigitalTimes full review. What do you think of The Legend Of Zelda: Breath Of The Wild so far? Which guides would you like to see next?
For Quartz, bots are a chance to build a new path for interacting with news (and news outlets)
He's been there for three weeks now -- though he is quick to point out that he was out of the office for one of them so it's really only been two weeks -- but that's not stopping Quartz from launching one of the Bot Studio's first experiments, a Twitter bot to help attendees of the NICAR conference. People going to #NICAR17 can ask a Twitter bot. Keefe says the Bot Studio, which is funded by a $240,000 grant from the Knight Foundation, will focus on two main areas: How bots and artificial intelligence can help journalists do their jobs better and how news consumers can use them to access news and information. Keefe joined Quartz after spending 16 years at WNYC. We spoke about the lessons he learned from public radio, his goals for the Bot Studio, and what it'll take for bots to catch on.
Time to Fold, Humans: Poker-Playing AI Beats Pros at Texas Hold'em
It is no mystery why poker is such a popular pastime: the dynamic card game produces drama in spades as players are locked in a complicated tango of acting and reacting that becomes increasingly tense with each escalating bet. The same elements that make poker so entertaining have also created a complex problem for artificial intelligence (AI). A study published today in Science describes an AI system called DeepStack that recently defeated professional human players in heads-up, no-limit Texas hold'em poker, an achievement that represents a leap forward in the types of problems AI systems can solve. DeepStack, developed by researchers at the University of Alberta, relies on the use of artificial neural networks that researchers trained ahead of time to develop poker intuition. During play, DeepStack uses its poker smarts to break down a complicated game into smaller, more manageable pieces that it can then work through on the fly.
To make better computers, researchers turn to molecular biology
March 2, 2017 --Computer engineers have created some amazingly small devices, capable of storing entire libraries of music and movies in the palm of your hand. But geneticists say Mother Nature can do even better. DNA, where all of biology's information is stored, is incredibly dense. The whole genome of an organism fits into a cell that is invisible to the naked eye. That's why computer scientists are turning to molecular biology to design the next best way to store humanity's ever-increasing collection of digital data.