Statistical Learning
A Learning-Based Optimal Uncertainty Quantification Method and Its Application to Ballistic Impact Problems
This paper concerns the study of optimal (supremum and infimum) uncertainty bounds for systems where the input (or prior) probability measure is only partially/imperfectly known (e.g., with only statistical moments and/or on a coarse topology) rather than fully specified. Such partial knowledge provides constraints on the input probability measures. The theory of Optimal Uncertainty Quantification allows us to convert the task into a constraint optimization problem where one seeks to compute the least upper/greatest lower bound of the system's output uncertainties by finding the extremal probability measure of the input. Such optimization requires repeated evaluation of the system's performance indicator (input to performance map) and is high-dimensional and non-convex by nature. Therefore, it is difficult to find the optimal uncertainty bounds in practice. In this paper, we examine the use of machine learning, especially deep neural networks, to address the challenge. We achieve this by introducing a neural network classifier to approximate the performance indicator combined with the stochastic gradient descent method to solve the optimization problem. We demonstrate the learning based framework on the uncertainty quantification of the impact of magnesium alloys, which are promising light-weight structural and protective materials. Finally, we show that the approach can be used to construct maps for the performance certificate and safety design in engineering practice.
Search Efficient Binary Network Embedding
Zhang, Daokun, Yin, Jie, Zhu, Xingquan, Zhang, Chengqi
Traditional network embedding primarily focuses on learning a continuous vector representation for each node, preserving network structure and/or node content information, such that off-the-shelf machine learning algorithms can be easily applied to the vector-format node representations for network analysis. However, the learned continuous vector representations are inefficient for large-scale similarity search, which often involves finding nearest neighbors measured by distance or similarity in a continuous vector space. In this paper, we propose a search efficient binary network embedding algorithm called BinaryNE to learn a binary code for each node, by simultaneously modeling node context relations and node attribute relations through a three-layer neural network. BinaryNE learns binary node representations through a stochastic gradient descent based online learning algorithm. The learned binary encoding not only reduces memory usage to represent each node, but also allows fast bit-wise comparisons to support faster node similarity search than using Euclidean distance or other distance measures. Extensive experiments and comparisons demonstrate that BinaryNE not only delivers more than 25 times faster search speed, but also provides comparable or better search quality than traditional continuous vector based network embedding methods. The binary codes learned by BinaryNE also render competitive performance on node classification and node clustering tasks. The source code of this paper is available at https://github.com/daokunzhang/BinaryNE.
Reducing Certified Regression to Certified Classification for General Poisoning Attacks
Adversarial training instances can severely distort a model's behavior. This work investigates certified regression defenses, which provide guaranteed limits on how much a regressor's prediction may change under a poisoning attack. Our key insight is that certified regression reduces to voting-based certified classification when using median as a model's primary decision function. Coupling our reduction with existing certified classifiers, we propose six new regressors provably-robust to poisoning attacks. To the extent of our knowledge, this is the first work that certifies the robustness of individual regression predictions without any assumptions about the data distribution and model architecture. We also show that the assumptions made by existing state-of-the-art certified classifiers are often overly pessimistic. We introduce a tighter analysis of model robustness, which in many cases results in significantly improved certified guarantees. Lastly, we empirically demonstrate our approaches' effectiveness on both regression and classification data, where the accuracy of up to 50% of test predictions can be guaranteed under 1% training set corruption and up to 30% of predictions under 4% corruption. Our source code is available at https://github.com/ZaydH/certified-regression.
Spectral Representation Learning for Conditional Moment Models
Wang, Ziyu, Luo, Yucen, Li, Yueru, Zhu, Jun, Schölkopf, Bernhard
Many problems in causal inference and economics can be formulated in the framework of conditional moment models, which characterize the target function through a collection of conditional moment restrictions. For nonparametric conditional moment models, efficient estimation often relies on preimposed conditions on various measures of ill-posedness of the hypothesis space, which are hard to validate when flexible models are used. In this work, we address this issue by proposing a procedure that automatically learns representations with controlled measures of ill-posedness. Our method approximates a linear representation defined by the spectral decomposition of a conditional expectation operator, which can be used for kernelized estimators and is known to facilitate minimax optimal estimation in certain settings. We show this representation can be efficiently estimated from data, and establish L2 consistency for the resulting estimator. We evaluate the proposed method on proximal causal inference tasks, exhibiting promising performance on high-dimensional, semi-synthetic data.
How much are the Artificial Intelligence Course Fees in Guwahati?
Artificial intelligence is a technology that is altering all facets of life despite a widespread lack of familiarity. It is a versatile tool that helps individuals to reconsider how we combine information, evaluate data, and use the insights obtained to enhance decision-making. It makes sense that one of the most in-demand skills in the technology industry, which has impacted practically every industry from cybersecurity to software to IoT, has to do with artificial intelligence (AI). Business processes may be made more effective, complications can be reduced, and the quality of life can be improved thanks to the innovative applications and services that are being quickly developed using AI.
feature-engineering-and-feature-selection/A Short Guide for Feature Engineering and Feature Selection.md at master · Yimeng-Zhang/feature-engineering-and-feature-selection · GitHub
Feature engineering and selection is the art/science of converting data to the best way possible, which involve an elegant blend of domain expertise, intuition and mathematics. This guide is a concise reference for beginners with most simple yet widely used techniques for feature engineering and selection. Any comments and commits are most welcome. The field of Machine Learning seeks to answer the question "How can we build computer systems that automatically improve with experience, and what are the fundamental laws that govern all learning processes?" Narrowly speaking, in data mining context, machine learning (ML) is the process of letting computers to learn from historical data, recognize pattern/relationship within data, and then make predictions. There can be many ways to divide the tasks that make up the ML workflow into phases. But generally the basic steps are similar as the graph above. Definition: any measurable property/characteristic of a phenomenon being observed. They are called'variables' because the value they take may vary (and it usually does) in a population. Note: In reality we may have mixed type of variable for a variety of reasons. For example, in credit scoring "Missed payment status" is a common variable that can take values 1, 2, 3 meaning that the customer has missed 1-3 payments in their account. And it can also take the value D, if the customer defaulted on that account. We may have to convert data types after certain steps of data cleaning.
Linear Regression on Boston Housing Dataset
In my previous blog, I covered the basics of linear regression and gradient descent. To get hands-on linear regression we will take an original dataset and apply the concepts that we have learned. We will take the Housing dataset which contains information about different houses in Boston. This data was originally a part of UCI Machine Learning Repository and has been removed now. We can also access this data from the scikit-learn library.
Choosing a Learning Rate for DNNs – Towards AI
Originally published on Towards AI the World's Leading AI and Technology News and Media Company. If you are building an AI-related product or service, we invite you to consider becoming an AI sponsor. At Towards AI, we help scale AI and technology startups. Let us help you unleash your technology to the masses. During the application process for an AI-based company, I was given a take-home assessment that included a machine learning task.
Near-Term Quantum Computing Techniques: Variational Quantum Algorithms, Error Mitigation, Circuit Compilation, Benchmarking and Classical Simulation
Huang, He-Liang, Xu, Xiao-Yue, Guo, Chu, Tian, Guojing, Wei, Shi-Jie, Sun, Xiaoming, Bao, Wan-Su, Long, Gui-Lu
Quantum computing is a game-changing technology for global academia, research centers and industries including computational science, mathematics, finance, pharmaceutical, materials science, chemistry and cryptography. Although it has seen a major boost in the last decade, we are still a long way from reaching the maturity of a full-fledged quantum computer. That said, we will be in the Noisy-Intermediate Scale Quantum (NISQ) era for a long time, working on dozens or even thousands of qubits quantum computing systems. An outstanding challenge, then, is to come up with an application that can reliably carry out a nontrivial task of interest on the near-term quantum devices with non-negligible quantum noise. To address this challenge, several near-term quantum computing techniques, including variational quantum algorithms, error mitigation, quantum circuit compilation and benchmarking protocols, have been proposed to characterize and mitigate errors, and to implement algorithms with a certain resistance to noise, so as to enhance the capabilities of near-term quantum devices and explore the boundaries of their ability to realize useful applications. Besides, the development of near-term quantum devices is inseparable from the efficient classical simulation, which plays a vital role in quantum algorithm design and verification, error-tolerant verification and other applications. This review will provide a thorough introduction of these near-term quantum computing techniques, report on their progress, and finally discuss the future prospect of these techniques, which we hope will motivate researchers to undertake additional studies in this field.