Statistical Learning
Storage Fit Learning with Feature Evolvable Streams
Hou, Bo-Jian, Yan, Yu-Hu, Zhao, Peng, Zhou, Zhi-Hua
Feature evolvable learning has been widely studied in recent years where old features will vanish and new features will emerge when learning with streams. Conventional methods usually assume that a label will be revealed after prediction at each time step. However, in practice, this assumption may not hold whereas no label will be given at most time steps. To tackle this problem, we leverage the technique of manifold regularization to utilize the previous similar data to assist the refinement of the online model. Nevertheless, this approach needs to store all previous data which is impossible in learning with streams that arrive sequentially in large volume. Thus we need a buffer to store part of them. Considering that different devices may have different storage budgets, the learning approaches should be flexible subject to the storage budget limit. In this paper, we propose a new setting: Storage-Fit Feature-Evolvable streaming Learning (SF2EL) which incorporates the issue of rarely-provided labels into feature evolution. Our framework is able to fit its behavior to different storage budgets when learning with feature evolvable streams with unlabeled data. Besides, both theoretical and empirical results validate that our approach can preserve the merit of the original feature evolvable learning i.e., can always track the best baseline and thus perform well at any time step.
MetAL: Active Semi-Supervised Learning on Graphs via Meta Learning
Madhawa, Kaushalya, Murata, Tsuyoshi
The objective of active learning (AL) is to train classification models with less number of labeled instances by selecting only the most informative instances for labeling. The AL algorithms designed for other data types such as images and text do not perform well on graph-structured data. Although a few heuristics-based AL algorithms have been proposed for graphs, a principled approach is lacking. In this paper, we propose MetAL, an AL approach that selects unlabeled instances that directly improve the future performance of a classification model. For a semi-supervised learning problem, we formulate the AL task as a bilevel optimization problem. Based on recent work in meta-learning, we use the meta-gradients to approximate the impact of retraining the model with any unlabeled instance on the model performance. Using multiple graph datasets belonging to different domains, we demonstrate that MetAL efficiently outperforms existing state-of-the-art AL algorithms.
Cooking Is All About People: Comment Classification On Cookery Channels Using BERT and Classification Models (Malayalam-English Mix-Code)
Kazhuparambil, Subramaniam, Kaushik, Abhishek
The scope of a lucrative career promoted by Google through its video distribution platform YouTube has attracted a large number of users to become content creators. An important aspect of this line of work is the feedback received in the form of comments which show how well the content is being received by the audience. However, volume of comments coupled with spam and limited tools for comment classification makes it virtually impossible for a creator to go through each and every comment and gather constructive feedback. Automatic classification of comments is a challenge even for established classification models, since comments are often of variable lengths riddled with slang, symbols and abbreviations. This is a greater challenge where comments are multilingual as the messages are often rife with the respective vernacular. In this work, we have evaluated top-performing classification models for classifying comments which are a mix of different combinations of English and Malayalam (only English, only Malayalam and Mix of English and Malayalam). The statistical analysis of results indicates that Multinomial Naive Bayes, K-Nearest Neighbors (KNN), Support Vector Machine (SVM), Random Forest and Decision Trees offer similar level of accuracy in comment classification. Further, we have also evaluated 3 multilingual transformer based language models (BERT, DISTILBERT and XLM) and compared their performance to the traditional machine learning classification techniques. XLM was the top-performing BERT model with an accuracy of 67.31. Random Forest with Term Frequency Vectorizer was the best performing model out of all the traditional classification models with an accuracy of 63.59.
FLAMBE: Structural Complexity and Representation Learning of Low Rank MDPs
Agarwal, Alekh, Kakade, Sham, Krishnamurthy, Akshay, Sun, Wen
The ability to learn effective transformations of complex data sources, sometimes called representation learning, is an essential primitive in modern machine learning, leading to remarkable achievements in language modeling, vision, and serving as a partial explanation for the success of deep learning more broadly (Bengio et al., 2013). In Reinforcement Learning (RL), several works have shown empirically that learning succinct representations of perceptual inputs can accelerate the search for decision-making policies (Pathak et al., 2017; Tang et al., 2017; Oord et al., 2018; Srinivas et al., 2020). However, representation learning for RL is far more subtle than it is for supervised learning (Du et al., 2019a; Van Roy and Dong, 2019; Lattimore and Szepesvari, 2019), and the theoretical foundations of representation learning for RL are nascent. The first question that arises in this context is: what is a good representation? Intuitively, a good representation should help us achieve greater sample efficiency on downstream tasks.
Testing the Robustness of AutoML Systems
Halvari, Tuomas, Nurminen, Jukka K., Mikkonen, Tommi
Automated machine learning (AutoML) systems aim at finding the best machine learning (ML) pipeline that automatically matches the task and data at hand. We investigate the robustness of machine learning pipelines generated with three AutoML systems, TPOT, H2O, and AutoKeras. In particular, we study the influence of dirty data on accuracy, and consider how using dirty training data may help create more robust solutions. Furthermore, we also analyze how the structure of the generated pipelines differs in different cases.
KNNImputer
The idea in kNN methods is to identify'k' samples in the dataset that are similar or close in the space. Then we use these'k' samples to estimate the value of the missing data points. Each sample's missing values are imputed using the mean value of the'k'-neighbors found in the dataset. Let's look at an example to understand this. Consider a pair of observations in a two-dimensional space (2,0), (2,2), (3,3).
How to Remove Outliers for Machine Learning
When modeling, it is important to clean the data sample to ensure that the observations best represent the problem. Sometimes a dataset can contain extreme values that are outside the range of what is expected and unlike the other data. These are called outliers and often machine learning modeling and model skill in general can be improved by understanding and even removing these outlier values. In this tutorial, you will discover outliers and how to identify and remove them from your machine learning dataset. Discover data cleaning, feature selection, data transforms, dimensionality reduction and much more in my new book, with 30 step-by-step tutorials and full Python source code. How to Use Statistics to Identify Outliers in Data Photo by Jeff Richardson, some rights reserved.
Machine Learning Algorithms Are Much More Fragile Than You Think
In William Gibson's 2010 novel Zero History, a character preparing to go in a high-stakes raid wears an oddly-patterned t-shirt that renders him invisible on the monitoring CCTVs. It's an idea many science fiction writers have written about, and it has captivated audiences so much because it challenges the notion that AI is unbeatable and all-knowingly. With a simple trick, someone can trick the algorithm? For good or for worse, machine learning algorithms can be tricked by slight changes to inputs, intentional or not, into its system. Recently in 2020, the cybersecurity firm McAfee showed that Mobileye -- the car intelligence system used by Tesla and other auto manufacturers -- could be fooled into accelerating 50 MPH over the speed limit just by plastering a strip of black tape two inches wide to a speed limit sign.
A step by step process to deal with a Predictive Analytical Problem
What is a machine learning project? What really a predictive analytical problem statement is? How we are going to solve this? Basically, using some previous information, prediction about the future is the base of machine learning models. The process of extracting information and generating trends is called training or modeling and telling about the future is called predictions.