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Artificial Intelligence Goes to Washington
Get ready because artificial intelligence is on the White House's radar, and it's taking the field seriously. The White House this week announced the new National Science and Technology Council (NSTC) Subcommittee on Machine Learning and Artificial Intelligence will meet for the first time next week, and the White House Office of Science and Technology Policy will cohost four workshops to create a dialogue around the positives and negatives of artificial intelligence and machine learning. "Like any transformative technology … artificial intelligence carries some risk and presents complex policy challenges along several dimensions, from jobs and the economy to safety and regulatory questions," Deputy U.S. Chief Technology Officer Ed Felten wrote. "For example, A.I. will create new jobs while phasing out some old ones--magnifying the importance of programs like TechHire that are preparing our workforce with the skills to get ahead in today's economy, and tomorrow's." According to Felten, the new subcommittee is meant to monitor advances and milestones in the field, including in the federal realm, the private sector, and internationally.
Wisdom of Crowds cluster ensemble
Alizadeh, Hosein, Yousefnezhad, Muhammad, Bidgoli, Behrouz Minaei
The Wisdom of Crowds is a phenomenon described in social science that suggests four criteria applicable to groups of people. It is claimed that, if these criteria are satisfied, then the aggregate decisions made by a group will often be better than those of its individual members. Inspired by this concept, we present a novel feedback framework for the cluster ensemble problem, which we call Wisdom of Crowds Cluster Ensemble (WOCCE). Although many conventional cluster ensemble methods focusing on diversity have recently been proposed, WOCCE analyzes the conditions necessary for a crowd to exhibit this collective wisdom. These include decentralization criteria for generating primary results, independence criteria for the base algorithms, and diversity criteria for the ensemble members. We suggest appropriate procedures for evaluating these measures, and propose a new measure to assess the diversity. We evaluate the performance of WOCCE against some other traditional base algorithms as well as state-of-the-art ensemble methods. The results demonstrate the efficiency of WOCCE's aggregate decision-making compared to other algorithms.
Fast methods for training Gaussian processes on large data sets
Moore, Christopher J., Chua, Alvin J. K., Berry, Christopher P. L., Gair, Jonathan R.
Gaussian process regression (GPR) is a non-parametric Bayesian technique for interpolating or fitting data. The main barrier to further uptake of this powerful tool rests in the computational costs associated with the matrices which arise when dealing with large data sets. Here, we derive some simple results which we have found useful for speeding up the learning stage in the GPR algorithm, and especially for performing Bayesian model comparison between different covariance functions. We apply our techniques to both synthetic and real data and quantify the speed-up relative to using nested sampling to numerically evaluate model evidences.
Unbiased Bayesian Inference for Population Markov Jump Processes via Random Truncations
Georgoulas, Anastasis, Hillston, Jane, Sanguinetti, Guido
We consider continuous time Markovian processes where populations of individual agents interact stochastically according to kinetic rules. Despite the increasing prominence of such models in fields ranging from biology to smart cities, Bayesian inference for such systems remains challenging, as these are continuous time, discrete state systems with potentially infinite state-space. Here we propose a novel efficient algorithm for joint state / parameter posterior sampling in population Markov Jump processes. We introduce a class of pseudo-marginal sampling algorithms based on a random truncation method which enables a principled treatment of infinite state spaces. Extensive evaluation on a number of benchmark models shows that this approach achieves considerable savings compared to state of the art methods, retaining accuracy and fast convergence. We also present results on a synthetic biology data set showing the potential for practical usefulness of our work.
High Dimensional Bayesian Optimisation and Bandits via Additive Models
Kandasamy, Kirthevasan, Schneider, Jeff, Poczos, Barnabas
Bayesian Optimisation (BO) is a technique used in optimising a $D$-dimensional function which is typically expensive to evaluate. While there have been many successes for BO in low dimensions, scaling it to high dimensions has been notoriously difficult. Existing literature on the topic are under very restrictive settings. In this paper, we identify two key challenges in this endeavour. We tackle these challenges by assuming an additive structure for the function. This setting is substantially more expressive and contains a richer class of functions than previous work. We prove that, for additive functions the regret has only linear dependence on $D$ even though the function depends on all $D$ dimensions. We also demonstrate several other statistical and computational benefits in our framework. Via synthetic examples, a scientific simulation and a face detection problem we demonstrate that our method outperforms naive BO on additive functions and on several examples where the function is not additive.
Online Optimization for Large-Scale Max-Norm Regularization
Max-norm regularizer has been extensively studied in the last decade as it promotes an effective low-rank estimation for the underlying data. However, such max-norm regularized problems are typically formulated and solved in a batch manner, which prevents it from processing big data due to possible memory budget. In this paper, hence, we propose an online algorithm that is scalable to large-scale setting. Particularly, we consider the matrix decomposition problem as an example, although a simple variant of the algorithm and analysis can be adapted to other important problems such as matrix completion. The crucial technique in our implementation is to reformulating the max-norm to an equivalent matrix factorization form, where the factors consist of a (possibly overcomplete) basis component and a coefficients one. In this way, we may maintain the basis component in the memory and optimize over it and the coefficients for each sample alternatively. Since the memory footprint of the basis component is independent of the sample size, our algorithm is appealing when manipulating a large collection of samples. We prove that the sequence of the solutions (i.e., the basis component) produced by our algorithm converges to a stationary point of the expected loss function asymptotically. Numerical study demonstrates encouraging results for the efficacy and robustness of our algorithm compared to the widely used nuclear norm solvers.
Support Vector Algorithms for Optimizing the Partial Area Under the ROC Curve
Narasimhan, Harikrishna, Agarwal, Shivani
The area under the ROC curve (AUC) is a widely used performance measure in machine learning. Increasingly, however, in several applications, ranging from ranking to biometric screening to medicine, performance is measured not in terms of the full area under the ROC curve, but in terms of the \emph{partial} area under the ROC curve between two false positive rates. In this paper, we develop support vector algorithms for directly optimizing the partial AUC between any two false positive rates. Our methods are based on minimizing a suitable proxy or surrogate objective for the partial AUC error. In the case of the full AUC, one can readily construct and optimize convex surrogates by expressing the performance measure as a summation of pairwise terms. The partial AUC, on the other hand, does not admit such a simple decomposable structure, making it more challenging to design and optimize (tight) convex surrogates for this measure. Our approach builds on the structural SVM framework of Joachims (2005) to design convex surrogates for partial AUC, and solves the resulting optimization problem using a cutting plane solver. Unlike the full AUC, where the combinatorial optimization needed in each iteration of the cutting plane solver can be decomposed and solved efficiently, the corresponding problem for the partial AUC is harder to decompose. One of our main contributions is a polynomial time algorithm for solving the combinatorial optimization problem associated with partial AUC. We also develop an approach for optimizing a tighter non-convex hinge loss based surrogate for the partial AUC using difference-of-convex programming. Our experiments on a variety of real-world and benchmark tasks confirm the efficacy of the proposed methods.
Modeling the Mind: A brief review
Creating an accurate simulation of the mind is no easy task, and while it took brilliant minds decades to advance us to where we're at right now, we are still ways off our final goal. It is therefore imperative to have more research carried out in this multidisciplinary field, taking in help from researchers in biology, neuroscience, computer science, but also mathematics, physics, chemistry and imaging, in order to speed up this process and tip the scales in our favor for the upcoming decades. This annual review hopes to provide the required information for anyone who is considering this domain as his future endeavor. The reviews will be tackling relatively global characteristics at first in order to familiarize the reader with the basic foundations, and will be getting progressively more specific and in tune with current research in the upcoming parts.
Alphabet surpasses Apple in market cap
A file photo dated 06 January 2004 shows Apple Computer's CEO Steve Jobs sitting in front of a project Apple Computer logo during his keynote speech at the MacWorld Expo in San Francisco, California, USA. Apple's (AAPL) epic fall on the stock market took a symbolic turn Thursday after its market value again dropped below its top rival's. That makes it second fiddle behind Google parent Alphabet (GOOGL) at 499.9 billion. Shares of Apple have been in freefall this year, dropping more than 14%, amid the company's disappointing first-quarter results. It's the second time this year Alphabet's market value has surpassed Apple's.
Rob Gronkowski featured on cover of Madden 17 video game
The Madden 17 video game cover will feature New England Patriots tight end Rob Gronkowski in all his spiking glory. The rough-and-tumble Gronkowski, known as much for his partying ways off the field as his touchdown-making ways on it, received word Thursday evening when it was announced on ESPN's "SportsCenter" show. Gronkowski, 27, becomes the first Patriots player as well as first tight end to make the cover. The popular video game, which debuted in 1988, featured legendary Raiders Coach John Madden on the cover until 2001, when Tennessee Titans running back Eddie George appeared on it. Among the players to appear on the cover were New York Giants receiver Odell Beckham Jr. last year, retired Detroit Lions running back Barry Sanders in 2014, Green Bay Packers quarterback Brett Favre in 2009 and Baltimore Ravens linebacker Ray Lewis in 2004.