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Asymptotic Errors for Teacher-Student Convex Generalized Linear Models (or : How to Prove Kabashima's Replica Formula)
Gerbelot, Cedric, Abbara, Alia, Krzakala, Florent
There has been a recent surge of interest in the study of asymptotic reconstruction performance in various cases of generalized linear estimation problems in the teacher-student setting, especially for the case of i.i.d standard normal matrices. In this work, we prove a general analytical formula for the reconstruction performance of convex generalized linear models, and go beyond such matrices by considering all rotationally-invariant data matrices with arbitrary bounded spectrum, proving a decade-old conjecture originally derived using the replica method from statistical physics. This is achieved by leveraging on state-of-the-art advances in message passing algorithms and the statistical properties of their iterates. Our proof is crucially based on the construction of converging sequences of an oracle multi-layer vector approximate message passing algorithm, where the convergence analysis is done by checking the stability of an equivalent dynamical system. Beyond its generality, our result also provides further insight into overparametrized non-linear models, a fundamental building block of modern machine learning. We illustrate our claim with numerical examples on mainstream learning methods such as logistic regression and linear support vector classifiers, showing excellent agreement between moderate size simulation and the asymptotic prediction.
ExKMC: Expanding Explainable $k$-Means Clustering
Frost, Nave, Moshkovitz, Michal, Rashtchian, Cyrus
Despite the popularity of explainable AI, there is limited work on effective methods for unsupervised learning. We study algorithms for $k$-means clustering, focusing on a trade-off between explainability and accuracy. Following prior work, we use a small decision tree to partition a dataset into $k$ clusters. This enables us to explain each cluster assignment by a short sequence of single-feature thresholds. While larger trees produce more accurate clusterings, they also require more complex explanations. To allow flexibility, we develop a new explainable $k$-means clustering algorithm, ExKMC, that takes an additional parameter $k' \geq k$ and outputs a decision tree with $k'$ leaves. We use a new surrogate cost to efficiently expand the tree and to label the leaves with one of $k$ clusters. We prove that as $k'$ increases, the surrogate cost is non-increasing, and hence, we trade explainability for accuracy. Empirically, we validate that ExKMC produces a low cost clustering, outperforming both standard decision tree methods and other algorithms for explainable clustering. Implementation of ExKMC available at https://github.com/navefr/ExKMC.
A Metric Learning Approach to Anomaly Detection in Video Games
Wilkins, Benedict, Watkins, Chris, Stathis, Kostas
Abstract--With the aim of designing automated tools that assist in the video game quality assurance process, we frame the problem of identifying bugs in video games as an anomaly detection (AD) problem. We develop State-State Siamese Networks (S3N) as an efficient deep metric learning approach to AD in this context and explore how it may be used as part of an automated testing tool. Finally, we show by empirical evaluation on a series of Atari games, that S3N is able to learn a meaningful embedding, and consequently is able to identify various common types of video game bugs. Video game development companies take significant steps at all stages of development to reduce the likelihood of bugs appearing in release code. These steps range from the use of software development paradigms early in the process to heavy investment in Quality Assurance (QA) closer to release.
Robust M-Estimation Based Bayesian Cluster Enumeration for Real Elliptically Symmetric Distributions
Schroth, Christian A., Muma, Michael
Robustly determining the optimal number of clusters in a data set is an essential factor in a wide range of applications. Cluster enumeration becomes challenging when the true underlying structure in the observed data is corrupted by heavy-tailed noise and outliers. Recently, Bayesian cluster enumeration criteria have been derived by formulating cluster enumeration as maximization of the posterior probability of candidate models. This article generalizes robust Bayesian cluster enumeration so that it can be used with any arbitrary Real Elliptically Symmetric (RES) distributed mixture model. Our framework also covers the case of M-estimators that allow for mixture models, which are decoupled from a specific probability distribution. Examples of Huber's and Tukey's M-estimators are discussed. We derive a robust criterion for data sets with finite sample size, and also provide an asymptotic approximation to reduce the computational cost at large sample sizes. The algorithms are applied to simulated and real-world data sets, including radar-based person identification, and show a significant robustness improvement in comparison to existing methods.
Graph Homomorphism Convolution
In this paper, we study the graph classification problem from the graph homomorphism perspective. We consider the homomorphisms from $F$ to $G$, where $G$ is a graph of interest (e.g. molecules or social networks) and $F$ belongs to some family of graphs (e.g. paths or non-isomorphic trees). We show that graph homomorphism numbers provide a natural invariant (isomorphism invariant and $\mathcal{F}$-invariant) embedding maps which can be used for graph classification. Viewing the expressive power of a graph classifier by the $\mathcal{F}$-indistinguishable concept, we prove the universality property of graph homomorphism vectors in approximating $\mathcal{F}$-invariant functions. In practice, by choosing $\mathcal{F}$ whose elements have bounded tree-width, we show that the homomorphism method is efficient compared with other methods.
Reasoning with Contextual Knowledge and Influence Diagrams
Influence diagrams (IDs) are well-known formalisms extending Bayesian networks to model decision situations under uncertainty. Although they are convenient as a decision theoretic tool, their knowledge representation ability is limited in capturing other crucial notions such as logical consistency. We complement IDs with the light-weight description logic (DL) EL to overcome such limitations. We consider a setup where DL axioms hold in some contexts, yet the actual context is uncertain. The framework benefits from the convenience of using DL as a domain knowledge representation language and the modelling strength of IDs to deal with decisions over contexts in the presence of contextual uncertainty. We define related reasoning problems and study their computational complexity.
Building an AI-Powered Searchable Video Archive
In this post, I'll show you how to build an AI-powered, searchable video archive using machine learning and Google Cloud–no experience required. One of my favorite apps ever is definitely Google Photos. In addition to backing up my precious pics to the cloud, it also makes all of my photos and videos searchable using machine learning. So if I type "pool" in the Photos app, it returns all everything it recognizes as a pool: This is all well and good if you just want to use somebody else's software. But on this website, we build our own PCs, store our own encryption keys, churn our own butter, and build our own Google Photos Videos app.
Tencent-backed Momenta begins robotaxi trials this fall
Chinese startup Momenta will begin test runs by October of self-driving taxis that require no human input, the company said Tuesday, aiming to make its fleet fully driverless by 2024. The "level 4" autonomous vehicles -- which can drive themselves in limited areas -- initially will have a person in the driver's seat for safety reasons. Testing starts in the city of Suzhou, near Shanghai. Momenta, whose investors include German automaker Daimler and internet services giant Tencent Holdings, looks to turn a profit in 2024 and start large-scale operation around China by 2028. The announcement comes amid a rush into China's robotaxi market by companies such as Baidu and startups Pony.ai and AutoX.
Thucydides And The Dragon: Artificial Intelligence And Sino-US Rivalry
"Made in China" used to mean cheap and poor quality, and probably involving the theft of intellectual property somewhere along the line. That perception has been out of date for many years now. Counterfeiting by Chinese manufacturers is still a major problem in some industries, but the best Chinese companies are world leaders in quality and in innovation. European telecoms utilities are alarmed by Trump's demand that they exclude Huawei components from their 5G rollout programmes: if they comply, their 5G services will be late and expensive. China's two mobile payments giants, Alibaba's Alipay and Tencent's WeChat Pay, both have many more active users than PayPal and Apple Pay combined.
Stop training more models, start deploying them - KDnuggets
The rumours that AI (and ML) will revolutionise healthcare have been around for a while [1]. And yes, we have seen some amazing uses of AI in healthcare [see, e.g., 2,3]. But, in my personal experience, the majority of the models trained in healthcare never make it to practice. Let's see why (or, scroll down and see how we solve it). Note: The statement "the majority of the models trained in … never make it to practice" is probably true across disciplines. Healthcare happens to be the one I am sure about.