Genre
CIS 472/572 – Machine Learning – Winter 2015
Please check Piazza regularly for announcements and discussion. I will attempt to post slides before lecture. Readings in CIML are required. Other readings are optional unless otherwise specified. Domingos, Pedro Domingos' video lectures on Coursera There are many excellent machine learning textbooks, but none of them is quite perfect for this class.
Grant Gochnauer: Awesome Humans -- Issue #100 – Awesome Humans – Medium
How stress works in the human body, to make or break us -- aeon.co Lots of research on how to manage stress which not surprisingly includes exercise but also highlights how certain stress in our lives can impact us forever. "Adverse early life experience involving poverty, abuse and neglect affects how genes are expressed, and determines how well brain regions such as the hippocampus, amygdala and prefrontal cortex develop and function during childhood into young adulthood. Indeed, the brain is continually changing with experience, which creates memories and alters brain architecture via mechanisms that are facilitated in part by circulating sex, stress and metabolic hormones and chemicals produced by the immune system. These insights have led to a new view of epigenetic changes over the life course."
Off the Map: The Rough Road Ahead for Self-Driving Cars in China
China is creating roadblocks for U.S. auto makers and tech companies to bringing self-driving cars to the world's largest auto market. Citing national security concerns, China is limiting the amount of mapping that can be done by foreign companies, as General Motors Co., Ford Motor Co., Alphabet Inc. and Apple Inc. rush to develop self-driving cars or the software behind them. High-definition maps are crucial for autonomous cars to help them discern their exact location, navigate tricky intersections and avoid fixed objects such as buildings. Global car makers already need to form a partnership with a local company to open factories in China, but some are skeptical they will be able to find a way to operate their autonomous-car software in China because of the mapping restrictions. Brian McClendon, an industry pioneer who helped created Google Maps and later led Uber Technologies Inc.'s self-driving effort, said he doubted U.S. software would ever be adopted for self-driving cars in China.
Google's AI Fight Club Will Train Systems to Defend Against Future Cyberattacks
When artificial intelligence (AI) is discussed today, most people are referring to machine learning algorithms or deep learning systems. While AI has advanced significantly over the years, the principle behind these technologies remains the same. Someone trains a system to receive certain data and asks it to produce a specified outcome -- it's up to the machine to develop its own algorithm to reach this outcome. Alas, while we've been able to create some very smart systems, they are not foolproof. Data science competition platform Kaggle wants to prepare AI systems for super-smart cyberattacks, and they're doing so by pitting AI against AI in a contest dubbed the Competition on Adversarial Attacks and Defenses.
Asymptotic Normality of the Median Heuristic
The median heuristic is a popular tool to set the bandwidth of radial basis function kernels. While its empirical performances make it a safe choice under most circumstances, there is little theoretical understanding of why this is the case. For large sample size, we show in this article that the median heuristic behaves approximately as the median of a distribution that we describe completely in the setting of kernel two-sample test and kernel change-point detection. More precisely, we show that the median heuristic is asymptotically normal around this value. We illustrate these findings when the underlying distributions are multivariate Gaussian distributions.
Complex and Holographic Embeddings of Knowledge Graphs: A Comparison
Trouillon, Théo, Nickel, Maximilian
Embeddings of knowledge graphs have received significant attention due to their excellent performance for tasks like link prediction and entity resolution. In this short paper, we are providing a comparison of two state-of-the-art knowledge graph embeddings for which their equivalence has recently been established, i.e., ComplEx and HolE [Nickel, Rosasco, and Poggio, 2016; Trouillon et al., 2016; Hayashi and Shimbo, 2017]. First, we briefly review both models and discuss how their scoring functions are equivalent. We then analyze the discrepancy of results reported in the original articles, and show experimentally that they are likely due to the use of different loss functions. In further experiments, we evaluate the ability of both models to embed symmetric and antisymmetric patterns. Finally, we discuss advantages and disadvantages of both models and under which conditions one would be preferable to the other.
Count-ception: Counting by Fully Convolutional Redundant Counting
Cohen, Joseph Paul, Boucher, Genevieve, Glastonbury, Craig A., Lo, Henry Z., Bengio, Yoshua
Counting objects in digital images is a process that should be replaced by machines. This tedious task is time consuming and prone to errors due to fatigue of human annotators. The goal is to have a system that takes as input an image and returns a count of the objects inside and justification for the prediction in the form of object localization. We repose a problem, originally posed by Lempitsky and Zisserman, to instead predict a count map which contains redundant counts based on the receptive field of a smaller regression network. The regression network predicts a count of the objects that exist inside this frame. By processing the image in a fully convolutional way each pixel is going to be accounted for some number of times, the number of windows which include it, which is the size of each window, (i.e., 32x32 = 1024). To recover the true count we take the average over the redundant predictions. Our contribution is redundant counting instead of predicting a density map in order to average over errors. We also propose a novel deep neural network architecture adapted from the Inception family of networks called the Count-ception network. Together our approach results in a 20% relative improvement (2.9 to 2.3 MAE) over the state of the art method by Xie, Noble, and Zisserman in 2016.
High-Dimensional Regression with Binary Coefficients. Estimating Squared Error and a Phase Transition
We consider a sparse linear regression model Y=X\beta^{*}+W where X has a Gaussian entries, W is the noise vector with mean zero Gaussian entries, and \beta^{*} is a binary vector with support size (sparsity) k. Using a novel conditional second moment method we obtain a tight up to a multiplicative constant approximation of the optimal squared error \min_{\beta}\|Y-X\beta\|_{2}, where the minimization is over all k-sparse binary vectors \beta. The approximation reveals interesting structural properties of the underlying regression problem. In particular, a) We establish that n^*=2k\log p/\log (2k/\sigma^{2}+1) is a phase transition point with the following "all-or-nothing" property. When n exceeds n^{*}, (2k)^{-1}\|\beta_{2}-\beta^*\|_0\approx 0, and when n is below n^{*}, (2k)^{-1}\|\beta_{2}-\beta^*\|_0\approx 1, where \beta_2 is the optimal solution achieving the smallest squared error. With this we prove that n^{*} is the asymptotic threshold for recovering \beta^* information theoretically. b) We compute the squared error for an intermediate problem \min_{\beta}\|Y-X\beta\|_{2} where minimization is restricted to vectors \beta with \|\beta-\beta^{*}\|_0=2k \zeta, for \zeta\in [0,1]. We show that a lower bound part \Gamma(\zeta) of the estimate, which corresponds to the estimate based on the first moment method, undergoes a phase transition at three different thresholds, namely n_{\text{inf,1}}=\sigma^2\log p, which is information theoretic bound for recovering \beta^* when k=1 and \sigma is large, then at n^{*} and finally at n_{\text{LASSO/CS}}. c) We establish a certain Overlap Gap Property (OGP) on the space of all binary vectors \beta when n\le ck\log p for sufficiently small constant c. We conjecture that OGP is the source of algorithmic hardness of solving the minimization problem \min_{\beta}\|Y-X\beta\|_{2} in the regime n
Prediction-Constrained Training for Semi-Supervised Mixture and Topic Models
Hughes, Michael C., Weiner, Leah, Hope, Gabriel, McCoy, Thomas H. Jr., Perlis, Roy H., Sudderth, Erik B., Doshi-Velez, Finale
Supervisory signals have the potential to make low-dimensional data representations, like those learned by mixture and topic models, more interpretable and useful. We propose a framework for training latent variable models that explicitly balances two goals: recovery of faithful generative explanations of high-dimensional data, and accurate prediction of associated semantic labels. Existing approaches fail to achieve these goals due to an incomplete treatment of a fundamental asymmetry: the intended application is always predicting labels from data, not data from labels. Our prediction-constrained objective for training generative models coherently integrates loss-based supervisory signals while enabling effective semi-supervised learning from partially labeled data. We derive learning algorithms for semi-supervised mixture and topic models using stochastic gradient descent with automatic differentiation. We demonstrate improved prediction quality compared to several previous supervised topic models, achieving predictions competitive with high-dimensional logistic regression on text sentiment analysis and electronic health records tasks while simultaneously learning interpretable topics.
Deep Reinforcement Learning with Successor Features for Navigation across Similar Environments
Zhang, Jingwei, Springenberg, Jost Tobias, Boedecker, Joschka, Burgard, Wolfram
Autonomous navigation is one of the core problems in mobile robotics. It can roughly be characterized as the ability of a robot to get from its current position to a designated goal location solely based on the input it receives from its on-board sensors. A popular approach to this problem relies on the successful combination of a series of different algorithms for the problems of simultaneous localization and mapping (SLAM), localization in a given map as well as path planning and control, all of which often depend on additional information given to the agent. Although individually the problems of SLAM, localization, path planning and control are well understood [1], [2], [3], and a lot of progress has been made on learning control [4], they have mainly been treated as separable problems within robotics and some often require human assistance during setup-time. For example, the majority of SLAM solutions are implemented as passive procedures relying on special exploration strategies or a human controlling the robot for sensory data acquisition. In addition, they typically require an expert to check as to whether the obtained map is accurate enough for path planning and localization. Our goal in this paper is to make first steps towards a solution for navigation tasks without explicit localization, mapping and path planning procedures.