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 Statistical Learning


Data Science Has Been Using Rebel Statistics for a Long Time

@machinelearnbot

Many of those who call themselves statisticians just won't admit that data science heavily relies on and uses (heretical, rule-breaking) statistical science, or they don't recognize the true statistical nature of these data science techniques (some are 15-year old), or are opposed to the modernization of their statistical arsenal. They already missed the train when machine learning became a popular discipline (also heavily based on statistics) more than 15 years ago. Now machine learning professionals, who are statistical practitioners working on problems such as clustering, far outnumber statisticians. Many times, I have interacted with statisticians who think that anyone not calling himself statistician, knows nothing or little about statistics; see my recent bio published here, or visit the LinkedIn profiles of many data scientists, to debunk this myth. Any statistical technique that is not in their old books are considered heretical at best, or non-statistic at worst, or most of the time, not understood.


10 types of regressions. Which one to use?

@machinelearnbot

The CRAN task view: "Robust statistical methods" gives a long list of regression methods, including many that Vincent mentions. Here a some that are not mentioned there: Regression in unusual spaces. It is usually addressed under the title "Compositional data" (see Wikipedia entry). The late John Aitchison founded this area of statistics. Googling his name "compositional data" gives access to a number of his articles.


Collection of Machine Learning Interview Questions

#artificialintelligence

Here is the link to coursera course for NLP Pick the software from the The Stanford NLP (Natural Language Processing) Group and input some text to view its parse tree, named entities, part of speech tags, etc.


A Factorization Machine Framework for Testing Bigram Embeddings in Knowledgebase Completion

arXiv.org Machine Learning

Embedding-based Knowledge Base Completion models have so far mostly combined distributed representations of individual entities or relations to compute truth scores of missing links. Facts can however also be represented using pairwise embeddings, i.e. embeddings for pairs of entities and relations. In this paper we explore such bigram embeddings with a flexible Factorization Machine model and several ablations from it. We investigate the relevance of various bigram types on the fb15k237 dataset and find relative improvements compared to a compositional model.


Random Projection Estimation of Discrete-Choice Models with Large Choice Sets

arXiv.org Machine Learning

We introduce sparse random projection, an important dimension-reduction tool from machine learning, for the estimation of discrete-choice models with high-dimensional choice sets. Initially, high-dimensional data are compressed into a lower-dimensional Euclidean space using random projections. Subsequently, estimation proceeds using cyclic monotonicity moment inequalities implied by the multinomial choice model; the estimation procedure is semi-parametric and does not require explicit distributional assumptions to be made regarding the random utility errors. The random projection procedure is justified via the Johnson-Lindenstrauss Lemma -- the pairwise distances between data points are preserved during data compression, which we exploit to show convergence of our estimator. The estimator works well in simulations and in an application to a supermarket scanner dataset.


Constructive Preference Elicitation by Setwise Max-margin Learning

arXiv.org Machine Learning

In this paper we propose an approach to preference elicitation that is suitable to large configuration spaces beyond the reach of existing state-of-the-art approaches. Our setwise max-margin method can be viewed as a generalization of max-margin learning to sets, and can produce a set of "diverse" items that can be used to ask informative queries to the user. Moreover, the approach can encourage sparsity in the parameter space, in order to favor the assessment of utility towards combinations of weights that concentrate on just few features. We present a mixed integer linear programming formulation and show how our approach compares favourably with Bayesian preference elicitation alternatives and easily scales to realistic datasets.


Trading-Off Cost of Deployment Versus Accuracy in Learning Predictive Models

arXiv.org Machine Learning

Predictive models are finding an increasing number of applications in many industries. As a result, a practical means for trading-off the cost of deploying a model versus its effectiveness is needed. Our work is motivated by risk prediction problems in healthcare. Cost-structures in domains such as healthcare are quite complex, posing a significant challenge to existing approaches. We propose a novel framework for designing cost-sensitive structured regularizers that is suitable for problems with complex cost dependencies. We draw upon a surprising connection to boolean circuits. In particular, we represent the problem costs as a multi-layer boolean circuit, and then use properties of boolean circuits to define an extended feature vector and a group regularizer that exactly captures the underlying cost structure. The resulting regularizer may then be combined with a fidelity function to perform model prediction, for example. For the challenging real-world application of risk prediction for sepsis in intensive care units, the use of our regularizer leads to models that are in harmony with the underlying cost structure and thus provide an excellent prediction accuracy versus cost tradeoff.


Elements of machine learning

@machinelearnbot

The official title of this free book available in PDF format is Machine Learning Cheat Sheet. See table of content screenshot below. The chapters 17 to 28 (the most interesting ones in my opinion) seem like a work in progress - I'm sure the authors intend to make them a bit bigger. For a more modern and applied book, get Dr Granville's book on data science.


Data Science Boot Camp

@machinelearnbot

The bootcamp experience is intense, but we aim to maximize learning while preventing burn-out. Metis believes that a student's brain is like a muscle, and to grow without injury the brain must take time to recover. Therefore, we operate five days a week from 9-6. Each Monday - Thursday consists of three hours of group classroom instruction and five hours of practical skill development and project work. Fridays are "personal investment days" for catch-up, independent work, special guest speakers, career-related work, and/or fun.


Open sourcing QMF for matrix factorization

#artificialintelligence

Since the objective is an expectation, we can use the Stochastic Gradient Descent (SGD) algorithm to minimize it, by iteratively minimizing the loss on sampled triplets of (user, positive item, negative item). Our implementation uses a form of parallel and asynchronous SGD updates (called Hogwild! [3]), which can give near-linear speedups in terms of the number of processors, especially when the data is sparse, so that concurrent updates are unlikely to be on the same parameters and overwrite each other. In the case of recommendation problems, the data is usually very sparse (unless, e.g., there are few items and most users have seen the same items), and this approach works very well.