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 Unsupervised or Indirectly Supervised Learning


Expert Briefing: Supervised vs. Unsupervised learning in AI

#artificialintelligence

I had the opportunity the other week to spend a couple of hours shooting the breeze with our lead data scientist Tijl Carpels. While we chatted over an overpriced macchiato on everything from Star Wars to crypto currency the talk very quickly settled on the use of supervised and unsupervised algorithms in AI.


Analysis of $p$-Laplacian Regularization in Semi-Supervised Learning

arXiv.org Machine Learning

We investigate a family of regression problems in a semi-supervised setting. The task is to assign real-valued labels to a set of $n$ sample points, provided a small training subset of $N$ labeled points. A goal of semi-supervised learning is to take advantage of the (geometric) structure provided by the large number of unlabeled data when assigning labels. We consider random geometric graphs, with connection radius $\epsilon(n)$, to represent the geometry of the data set. Functionals which model the task reward the regularity of the estimator function and impose or reward the agreement with the training data. Here we consider the discrete $p$-Laplacian regularization. We investigate asymptotic behavior when the number of unlabeled points increases, while the number of training points remains fixed. We uncover a delicate interplay between the regularizing nature of the functionals considered and the nonlocality inherent to the graph constructions. We rigorously obtain almost optimal ranges on the scaling of $\epsilon(n)$ for the asymptotic consistency to hold. We prove that the minimizers of the discrete functionals in random setting converge uniformly to the desired continuum limit. Furthermore we discover that for the standard model used there is a restrictive upper bound on how quickly $\epsilon(n)$ must converge to zero as $n \to \infty$. We introduce a new model which is as simple as the original model, but overcomes this restriction.


Safe Semi-Supervised Learning of Sum-Product Networks

arXiv.org Machine Learning

In several domains obtaining class annotations is expensive while at the same time unlabelled data are abundant. While most semi-supervised approaches enforce restrictive assumptions on the data distribution, recent work has managed to learn semi-supervised models in a non-restrictive regime. However, so far such approaches have only been proposed for linear models. In this work, we introduce semi-supervised parameter learning for Sum-Product Networks (SPNs). SPNs are deep probabilistic models admitting inference in linear time in number of network edges. Our approach has several advantages, as it (1) allows generative and discriminative semi-supervised learning, (2) guarantees that adding unlabelled data can increase, but not degrade, the performance (safe), and (3) is computationally efficient and does not enforce restrictive assumptions on the data distribution. We show on a variety of data sets that safe semi-supervised learning with SPNs is competitive compared to state-of-the-art and can lead to a better generative and discriminative objective value than a purely supervised approach.


Machine learning concepts: styles of machine learning

#artificialintelligence

This is the first in a series of posts about machine learning concepts, where we'll cover everything from learning styles to new dimensions in machine learning research. What makes machine learning so successful? The answer lies in the core concept of machine learning: a machine can learn from examples and experience. Before machine learning, machines were programmed with specific instructions and had no need to learn on their own. A machine (without machine learning) is born knowing exactly what it's supposed to do and how to do it, like a robot arm on an assembly line.


[P] Code from the "Class-Splitting Generative Adversarial Networks" paper • r/MachineLearning

@machinelearnbot

Honestly, your results look awesome and the idea is simple yet effective and can be applied in addition to many other GAN tricks. If only the presentation were more readable, you would get way more attention from this subreddit.


Find Needles in Data Haystacks with Unsupervised Learning

#artificialintelligence

There are valuable insights buried within your data, but they can be virtually impossible to find manually. Every time a data scientist spends hours immersed in data, wrangling and tweaking a mathematical code or script fragments, the dream of data science and machine learning bringing agility to your organization seems to retreat. Manual data science for industrial processes can be extremely counter-productive, especially when businesses embracing the IIoT are greatly emphasizing superior dexterity in operations. Any opportunity which can speed up delivery and output should be seized by every aspiring industrial manufacturer. One of the biggest challenges for the industrial digital enterprise is extracting precise outcomes by channeling huge volumes of data into meaningful information, and then performing accurate analyses to streamline business processes.


Occam's razor and machine learning - Data Points

#artificialintelligence

In the last instalment of this blog series, we discussed objectives and accuracy in machine learning. And we described two crucial tests for the utility of a machine learning model: The model must be sufficiently accurate and we must be able to deploy the model so that it can produce actionable outputs from the available data. We then introduced a real-world scenario -- predicting train failures up to 36 hours in advance of their occurrence using sensor data -- to illustrate the application of those tests. But how did we decide which of the multitude of machine learning algorithms to use to train our model in the first place? To answer this question, we need to revisit the main classes of machine learning algorithms.


Interpretable Graph-Based Semi-Supervised Learning via Flows

arXiv.org Machine Learning

In this paper, we consider the interpretability of the foundational Laplacian-based semi-supervised learning approaches on graphs. We introduce a novel flow-based learning framework that subsumes the foundational approaches and additionally provides a detailed, transparent, and easily understood expression of the learning process in terms of graph flows. As a result, one can visualize and interactively explore the precise subgraph along which the information from labeled nodes flows to an unlabeled node of interest. Surprisingly, the proposed framework avoids trading accuracy for interpretability, but in fact leads to improved prediction accuracy, which is supported both by theoretical considerations and empirical results. The flow-based framework guarantees the maximum principle by construction and can handle directed graphs in an out-of-the-box manner.


An introduction to representation learning

#artificialintelligence

Although many companies today possess massive amounts of data, the vast majority of that data is often unstructured and unlabeled. In fact, the amount of data that is appropriately labeled for a specific business need is typically quite small (possibly even zero), and acquiring new labels is usually a slow, expensive endeavor. As a result, algorithms that can extract features from unlabeled data to improve the performance of data-limited tasks are quite valuable. Most machine learning practitioners are first exposed to feature extraction techniques through unsupervised learning. In unsupervised learning, an algorithm attempts to discover the latent features that describe a data set's "structure" under certain (either explicit or implicit) assumptions.


Pseudo-labeling a simple semi-supervised learning method - Data, what now?

@machinelearnbot

The foundation of every machine learning project is data – the one thing you cannot do without. In this post, I will show how a simple semi-supervised learning method called pseudo-labeling that can increase the performance of your favorite machine learning models by utilizing unlabeled data. Does that mean that unlabeled data is useless for supervised tasks like classification and regression? Aside from using the extra data for analytic purposes, we can even use it to help train our model with semi-supervised learning – combining both unlabeled and labeled data for model training. The main idea is simple.