Goto

Collaborating Authors

 Regression


Logistic Regression

#artificialintelligence

In this article, we will be learning about how we can implement logistic regression by writing Python code. You must be wondering what is logistic regression and what is the theory behind it? What python packages are involved while implementing logistic regression? You must be coming up with many more questions but I will try to answer as many as questions possible. Well, you have chosen the right article.


Stochastic Intervention for Causal Inference via Reinforcement Learning

arXiv.org Artificial Intelligence

Causal inference methods are widely applied in various decision-making domains such as precision medicine, optimal policy and economics. Central to causal inference is the treatment effect estimation of intervention strategies, such as changes in drug dosing and increases in financial aid. Existing methods are mostly restricted to the deterministic treatment and compare outcomes under different treatments. However, they are unable to address the substantial recent interest of treatment effect estimation under stochastic treatment, e.g., "how all units health status change if they adopt 50\% dose reduction". In other words, they lack the capability of providing fine-grained treatment effect estimation to support sound decision-making. In our study, we advance the causal inference research by proposing a new effective framework to estimate the treatment effect on stochastic intervention. Particularly, we develop a stochastic intervention effect estimator (SIE) based on nonparametric influence function, with the theoretical guarantees of robustness and fast convergence rates. Additionally, we construct a customised reinforcement learning algorithm based on the random search solver which can effectively find the optimal policy to produce the greatest expected outcomes for the decision-making process. Finally, we conduct an empirical study to justify that our framework can achieve significant performance in comparison with state-of-the-art baselines.


Characterizing the SLOPE Trade-off: A Variational Perspective and the Donoho-Tanner Limit

arXiv.org Machine Learning

Sorted l1 regularization has been incorporated into many methods for solving high-dimensional statistical estimation problems, including the SLOPE estimator in linear regression. In this paper, we study how this relatively new regularization technique improves variable selection by characterizing the optimal SLOPE trade-off between the false discovery proportion (FDP) and true positive proportion (TPP) or, equivalently, between measures of type I error and power. Assuming a regime of linear sparsity and working under Gaussian random designs, we obtain an upper bound on the optimal trade-off for SLOPE, showing its capability of breaking the Donoho-Tanner power limit. To put it into perspective, this limit is the highest possible power that the Lasso, which is perhaps the most popular l1-based method, can achieve even with arbitrarily strong effect sizes. Next, we derive a tight lower bound that delineates the fundamental limit of sorted l1 regularization in optimally trading the FDP off for the TPP. Finally, we show that on any problem instance, SLOPE with a certain regularization sequence outperforms the Lasso, in the sense of having a smaller FDP, larger TPP and smaller l2 estimation risk simultaneously. Our proofs are based on a novel technique that reduces a variational calculus problem to a class of infinite-dimensional convex optimization problems and a very recent result from approximate message passing theory.


Reaction GIFs Offer A New Key To Emotion Recognition In NLP

#artificialintelligence

New research out of China is offering a novel method for Natural Language Processing (NLP) to perform sentiment analysis on social media forums and language research datasets – by categorizing and labeling animated GIFs that are posted in response to text announcements. The researchers, led by Boaz Shmueli of National Tsing Hua University at Taiwan, have used Twitter's in-built database of reaction GIFs as an index to quantify the affective state of a user's response, obviating the need to negotiate multiple language responses, the challenge of detecting sarcasm, or of identifying core emotional temperature from ambiguous or excessively brief responses. Clicking the'GIF' button when composing a Twitter post offers a standard set of labeled animated GIFs that are potentially easier for NLP to parse into'identified' emotions than plain-text language. The paper characterizes the use of reaction GIFs in this way as'a new type of label, not yet available in NLP emotion datasets', and notes that existing datasets either use the dimensional model of emotion or the discrete emotions model, neither of which offers this kind of insight. An animated GIF response to a user post.


Networked Federated Multi-Task Learning

arXiv.org Machine Learning

Many important application domains generate distributed collections of heterogeneous local datasets. These local datasets are often related via an intrinsic network structure that arises from domain-specific notions of similarity between local datasets. Different notions of similarity are induced by spatiotemporal proximity, statistical dependencies, or functional relations. We use this network structure to adaptively pool similar local datasets into nearly homogenous training sets for learning tailored models. Our main conceptual contribution is to formulate networked federated learning using the concept of generalized total variation (GTV) minimization as a regularizer. This formulation is highly flexible and can be combined with almost any parametric model including Lasso or deep neural networks. We unify and considerably extend some well-known approaches to federated multi-task learning. Our main algorithmic contribution is a novel federated learning algorithm that is well suited for distributed computing environments such as edge computing over wireless networks. This algorithm is robust against model misspecification and numerical errors arising from limited computational resources including processing time or wireless channel bandwidth. As our main technical contribution, we offer precise conditions on the local models as well on their network structure such that our algorithm learns nearly optimal local models. Our analysis reveals an interesting interplay between the (information-) geometry of local models and the (cluster-) geometry of their network.


Stochastic Intervention for Causal Effect Estimation

arXiv.org Artificial Intelligence

Causal inference methods are widely applied in various decision-making domains such as precision medicine, optimal policy and economics. Central to these applications is the treatment effect estimation of intervention strategies. Current estimation methods are mostly restricted to the deterministic treatment, which however, is unable to address the stochastic space treatment policies. Moreover, previous methods can only make binary yes-or-no decisions based on the treatment effect, lacking the capability of providing fine-grained effect estimation degree to explain the process of decision making. In our study, we therefore advance the causal inference research to estimate stochastic intervention effect by devising a new stochastic propensity score and stochastic intervention effect estimator (SIE). Meanwhile, we design a customized genetic algorithm specific to stochastic intervention effect (Ge-SIO) with the aim of providing causal evidence for decision making. We provide the theoretical analysis and conduct an empirical study to justify that our proposed measures and algorithms can achieve a significant performance lift in comparison with state-of-the-art baselines.


Logistic Regression -Beginners Guide in Python - Analytics India Magazine

#artificialintelligence

Most of the supervised learning problems in machine learning are classification problems. Classification is the task of assigning a data point with a suitable class. Suppose a pet classification problem. If we input certain features, the machine learning model will tell us whether the given features belong to a cat or a dog. Cat and dog are the two classes here.


15 Best YouTube Channels to Learn Data Science in 2021

#artificialintelligence

YouTube is a great platform for learners and has some best channels for learning data science. That's why I thought to share with you the 15 Best YouTube Channels to Learn Data Science. So if you are planning to learn data science, then these data science YouTube channels will help you to understand the fundamentals of data science. Now without any further ado, let's start finding the best youtube channels to learn data science- Math is essential for data science and machine learning to understand how machine learning algorithms work. So if you want to learn math concepts, then you should check this YouTube channel.


Group selection and shrinkage with application to sparse semiparametric modeling

arXiv.org Machine Learning

Sparse regression and classification estimators capable of group selection have application to an assortment of statistical problems, from multitask learning to sparse additive modeling to hierarchical selection. This work introduces a class of group-sparse estimators that combine group subset selection with group lasso or ridge shrinkage. We develop an optimization framework for fitting the nonconvex regularization surface and present finite-sample error bounds for estimation of the regression function. Our methods and analyses accommodate the general setting where groups overlap. As an application of group selection, we study sparse semiparametric modeling, a procedure that allows the effect of each predictor to be zero, linear, or nonlinear. For this task, the new estimators improve across several metrics on synthetic data compared to alternatives. Finally, we demonstrate their efficacy in modeling supermarket foot traffic and economic recessions using many predictors. All of our proposals are made available in the scalable implementation grpsel.


Sometimes more data can hurt!

#artificialintelligence

On a recent blog post I've discussed a scalable sparse linear regression model I've developed at work. One of it's interesting properties is that it's an interpolating model – meaning it has 0-training error. This is because it's over parameterized and thus can fit the training data perfectly. While 0-training error is usually associated with over-fiting, the model seems to perform pretty well on the test set. Reports of hugely over-parameterized models that seem to not suffer from overfiting (especially in deep learning) have been accumulating in recent years and so the literature on subject.