Statistical Learning
End-to-end Kernel Learning via Generative Random Fourier Features
Fang, Kun, Huang, Xiaolin, Liu, Fanghui, Yang, Jie
Random Fourier features enable researchers to build feature map to learn the spectral distribution of the underlying kernel. Current distribution-based methods follow a two-stage scheme: they first learn and optimize the feature map by solving the kernel alignment problem, then learn a linear classifier on the features. However, since the ideal kernel in kernel alignment problem is not necessarily optimal in classification tasks, the generalization performance of the random features learned in this two-stage manner can perhaps be further improved. To address this issue, we propose an end-to-end, one-stage kernel learning approach, called generative random Fourier features, which jointly learns the features and the classifier. A generative network is involved to implicitly learn and to sample from the distribution of the latent kernel. Random features are then built via the generative weights and followed by a linear classifier parameterized as a full-connected layer. We jointly train the generative network and the classifier by solving the empirical risk minimization problem for a one-stage solution. Straightly minimizing the loss between predictive and true labels brings better generalization performance. Besides, this end-to-end strategy allows us to increase the depth of features, resulting in multi-layer architecture and exhibiting strong linear-separable pattern. Empirical results demonstrate the superiority of our method in classification tasks over other two-stage kernel learning methods. Finally, we investigate the robustness of proposed method in defending adversarial attacks, which shows that the randomization and resampling mechanism associated with the learned distribution can alleviate the performance decrease brought by adversarial examples.
Regularised Text Logistic Regression: Key Word Detection and Sentiment Classification for Online Reviews
Chen, Ying, Liu, Peng, Teo, Chung Piaw
Online customer reviews have become important for managers and executives in the hospitality and catering industry who wish to obtain a comprehensive understanding of their customers' demands and expectations. We propose a Regularized Text Logistic (RTL) regression model to perform text analytics and sentiment classification on unstructured text data, which automatically identifies a set of statistically significant and operationally insightful word features, and achieves satisfactory predictive classification accuracy. We apply the RTL model to two online review datasets, Restaurant and Hotel, from TripAdvisor. Our results demonstrate satisfactory classification performance compared with alternative classifiers with a highest true positive rate of 94.9%. Moreover, RTL identifies a small set of word features, corresponding to 3% for Restaurant and 20% for Hotel, which boosts working efficiency by allowing managers to drill down into a much smaller set of important customer reviews. We also develop the consistency, sparsity and oracle property of the estimator.
Biclustering with Alternating K-Means
Biclustering is the task of simultaneously clustering the rows and columns of the data matrix into different subgroups such that the rows and columns within a subgroup exhibit similar patterns. In this paper, we consider the case of producing exclusive row and column biclusters. We provide a new formulation of the biclustering problem based on the idea of minimizing the empirical clustering risk. We develop and prove a consistency result with respect to the empirical clustering risk. Since the optimization problem is combinatorial in nature, finding the global minimum is computationally intractable. In light of this fact, we propose a simple and novel algorithm that finds a local minimum by alternating the use of an adapted version of the k-means clustering algorithm between columns and rows. We evaluate and compare the performance of our algorithm to other related biclustering methods on both simulated data and real-world gene expression data sets. The results demonstrate that our algorithm is able to detect meaningful structures in the data and outperform other competing biclustering methods in various settings and situations.
Proxy Network for Few Shot Learning
Xiao, Bin, Liu, Chien-Liang, Hsaio, Wen-Hoar
The use of a few examples for each class to train a predictive model that can be generalized to novel classes is a crucial and valuable research direction in artificial intelligence. This work addresses this problem by proposing a few-shot learning (FSL) algorithm called proxy network under the architecture of meta-learning. Metric-learning based approaches assume that the data points within the same class should be close, whereas the data points in the different classes should be separated as far as possible in the embedding space. We conclude that the success of metric-learning based approaches lies in the data embedding, the representative of each class, and the distance metric. In this work, we propose a simple but effective end-to-end model that directly learns proxies for class representative and distance metric from data simultaneously. We conduct experiments on CUB and mini-ImageNet datasets in 1-shot-5-way and 5-shot-5-way scenarios, and the experimental results demonstrate the superiority of our proposed method over state-of-the-art methods. Besides, we provide a detailed analysis of our proposed method.
Non-convex Learning via Replica Exchange Stochastic Gradient MCMC
Deng, Wei, Feng, Qi, Gao, Liyao, Liang, Faming, Lin, Guang
Replica exchange Monte Carlo (reMC), also known as parallel tempering, is an important technique for accelerating the convergence of the conventional Markov Chain Monte Carlo (MCMC) algorithms. However, such a method requires the evaluation of the energy function based on the full dataset and is not scalable to big data. The na\"ive implementation of reMC in mini-batch settings introduces large biases, which cannot be directly extended to the stochastic gradient MCMC (SGMCMC), the standard sampling method for simulating from deep neural networks (DNNs). In this paper, we propose an adaptive replica exchange SGMCMC (reSGMCMC) to automatically correct the bias and study the corresponding properties. The analysis implies an acceleration-accuracy trade-off in the numerical discretization of a Markov jump process in a stochastic environment. Empirically, we test the algorithm through extensive experiments on various setups and obtain the state-of-the-art results on CIFAR10, CIFAR100, and SVHN in both supervised learning and semi-supervised learning tasks.
Individual Calibration with Randomized Forecasting
Zhao, Shengjia, Ma, Tengyu, Ermon, Stefano
Machine learning applications often require calibrated predictions, e.g. a 90\% credible interval should contain the true outcome 90\% of the times. However, typical definitions of calibration only require this to hold on average, and offer no guarantees on predictions made on individual samples. Thus, predictions can be systematically over or under confident on certain subgroups, leading to issues of fairness and potential vulnerabilities. We show that calibration for individual samples is possible in the regression setup if the predictions are randomized, i.e. outputting randomized credible intervals. Randomization removes systematic bias by trading off bias with variance. We design a training objective to enforce individual calibration and use it to train randomized regression functions. The resulting models are more calibrated for arbitrarily chosen subgroups of the data, and can achieve higher utility in decision making against adversaries that exploit miscalibrated predictions.
Machine Learning Algorithms. Here's the End-to-End.
While there are several documents and articles on machine learning algorithms, I wanted to provide a summary of the most common ones I use as a professional data scientist. Additionally, I will include some sample code with dummy data so that you can start executing various models! Whereas unsupervised learning, like the commonly used K-means algorithm, aims to groups similar groups of data together without labels, supervised learning, or classification -- well, classifies data into various categories. A simple example of classification is described below. The classification model learns from the features about the fruits to suggest an input food a fruit label.
Mitigating Bias in Machine Learning: An introduction to MLFairnessPipeline
Bias takes many different forms and impact all groups of people. It can range from implicit to explicit and is often very difficult to detect. In the field of machine learning bias is often subtle and hard to identify, let alone solve. Why is this a problem? Implicit bias in machine learning has very real consequences including denial of a loan, a lengthier prison sentence, and many other harmful outcomes for underprivileged groups.
Machine Learning Classification Bootcamp in Python
Free Coupon Discount - Build 10 Practical Projects and Advance Your Skills in Machine Learning Using Python and Scikit Learn Created by Dr. Ryan Ahmed, Ph.D., MBA, Kirill Eremenko, Hadelin de Ponteves, Mitchell Bouchard, SuperDataScience Team Students also bought Machine Learning A-Z: Hands-On Python & R In Data Science Python for Data Science and Machine Learning Bootcamp Machine Learning, Data Science and Deep Learning with Python Machine Learning with Javascript A Beginner's Guide To Machine Learning with Unity Preview this Udemy Course GET COUPON CODE Description Are you ready to master Machine Learning techniques and Kick-off your career as a Data Scientist?! You came to the right place! Machine Learning skill is one of the top skills to acquire in 2019 with an average salary of over $114,000 in the United States according to PayScale! The total number of ML jobs over the past two years has grown around 600 percent and expected to grow even more by 2020. This course provides students with knowledge, hands-on experience of state-of-the-art machine learning classification techniques such as Logistic Regression Decision Trees Random Forest Naïve Bayes Support Vector Machines (SVM) In this course, we are going to provide students with knowledge of key aspects of state-of-the-art classification techniques.
Build an IoT hub for streaming, storing, and analyzing sensor data in the cloud: Connect an Android device to the IBM Cloud, build a Node-RED dashboard, and build an AI classifier
In this tutorial, we present the high-level steps that are involved in connecting an Android device to the cloud and developing analytics models to analyze sensor data. By the end of this tutorial you should be able to set up your own IoT hub for streaming, storing and processing device data. The following figure shows the architecture of our sample app. This tutorial requires an Android device (smartphone), an internet connection, and an IBM Cloud account. In Step 1 you will create an account on IBM Cloud and install an application on your Android phone.