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 Statistical Learning


Cross-Layer Approximation For Printed Machine Learning Circuits

arXiv.org Artificial Intelligence

Printed electronics (PE) feature low non-recurring engineering costs and low per unit-area fabrication costs, enabling thus extremely low-cost and on-demand hardware. Such low-cost fabrication allows for high customization that would be infeasible in silicon, and bespoke architectures prevail to improve the efficiency of emerging PE machine learning (ML) applications. However, even with bespoke architectures, the large feature sizes in PE constraint the complexity of the ML models that can be implemented. In this work, we bring together, for the first time, approximate computing and PE design targeting to enable complex ML models, such as Multi-Layer Perceptrons (MLPs) and Support Vector Machines (SVMs), in PE. To this end, we propose and implement a cross-layer approximation, tailored for bespoke ML architectures. At the algorithmic level we apply a hardware-driven coefficient approximation of the ML model and at the circuit level we apply a netlist pruning through a full search exploration. In our extensive experimental evaluation we consider 14 MLPs and SVMs and evaluate more than 4300 approximate and exact designs. Our results demonstrate that our cross approximation delivers Pareto optimal designs that, compared to the state-of-the-art exact designs, feature 47% and 44% average area and power reduction, respectively, and less than 1% accuracy loss.


From graph cuts to isoperimetric inequalities: Convergence rates of Cheeger cuts on data clouds

arXiv.org Machine Learning

In this work we study statistical properties of graph-based clustering algorithms that rely on the optimization of balanced graph cuts, the main example being the optimization of Cheeger cuts. We consider proximity graphs built from data sampled from an underlying distribution supported on a generic smooth compact manifold $M$. In this setting, we obtain high probability convergence rates for both the Cheeger constant and the associated Cheeger cuts towards their continuum counterparts. The key technical tools are careful estimates of interpolation operators which lift empirical Cheeger cuts to the continuum, as well as continuum stability estimates for isoperimetric problems. To our knowledge the quantitative estimates obtained here are the first of their kind.


Universally Consistent Online Learning with Arbitrarily Dependent Responses

arXiv.org Machine Learning

This work provides an online learning rule that is universally consistent under processes on(X, Y) pairs, under conditions only on the X process. As a special case, the conditions admit all processes on (X,Y) such that the process on X is stationary. This generalizes past results which required stationarity for the joint process on(X, Y), and additionally required this process to be ergodic. In particular, this means that ergodicity is superfluous for the purpose of universally consistent online learning.


Sparse Subspace Clustering for Concept Discovery (SSCCD)

arXiv.org Machine Learning

Concepts are key building blocks of higher level human understanding. Explainable AI (XAI) methods have shown tremendous progress in recent years, however, local attribution methods do not allow to identify coherent model behavior across samples and therefore miss this essential component. In this work, we study concept-based explanations and put forward a new definition of concepts as low-dimensional subspaces of hidden feature layers. We novelly apply sparse subspace clustering to discover these concept subspaces. Moving forward, we derive insights from concept subspaces in terms of localized input (concept) maps, show how to quantify concept relevances and lastly, evaluate similarities and transferability between concepts. We empirically demonstrate the soundness of the proposed Sparse Subspace Clustering for Concept Discovery (SSCCD) method for a variety of different image classification tasks. This approach allows for deeper insights into the actual model behavior that would remain hidden from conventional input-level heatmaps.


Deep Learning Prerequisites: Linear Regression in Python

#artificialintelligence

Deep Learning Prerequisites: Linear Regression in Python Data science: Learn linear regression from scratch and build your own working program in Python for data analysis. BESTSELLER 22,535 students enrolled Created by Lazy Programmer Inc.  English [Auto-generated], Spanish [Auto-generated] Preview this course  - GET COUPON CODE Free Coupon Discount Udemy Online Courses


Econometrics Is The Original Data Science

#artificialintelligence

I remember beginning my first online course in machine learning and realising that I already knew most of it. I'm going to preface this article by saying that I'm a trained and journal published econometrician -- I'm biased. Do you know who is also biased? Joshua Angrist -- a 2021 Nobel Prize winner whose video I discovered saying the same thing while researching for this video. If you're reading this, I'm assuming you have some interest in data science- there's a lot you can learn from Econometrics, so buckle up and listen in.


Deep Learning Is Hitting a Wall

#artificialintelligence

No single AI approach will ever be enough on its own; we must master the art of putting diverse approaches together. Few fields have been more filled with hype and bravado than artificial intelligence (AI). It has flitted from fad to fad decade by decade, always promising the moon and only occasionally delivering. One minute it was expert systems, next it was Bayesian networks, and then support vector machines. Nowadays, the flavor of choice has been deep learning, the multibillion-dollar technique that drives so much of contemporary AI. But deep learning is at its best when all we need are rough-ready results, where stakes are low and perfect results optional.


Classification from Positive and Biased Negative Data with Skewed Labeled Posterior Probability

arXiv.org Machine Learning

The binary classification problem has a situation where only biased data are observed in one of the classes. In this paper, we propose a new method to approach the positive and biased negative (PbN) classification problem, which is a weakly supervised learning method to learn a binary classifier from positive data and negative data with biased observations. We incorporate a method to correct the negative impact due to skewed confidence, which represents the posterior probability that the observed data are positive. This reduces the distortion of the posterior probability that the data are labeled, which is necessary for the empirical risk minimization of the PbN classification problem. We verified the effectiveness of the proposed method by numerical experiments and real data analysis.


Lifelong Adaptive Machine Learning for Sensor-based Human Activity Recognition Using Prototypical Networks

arXiv.org Artificial Intelligence

Continual learning, also known as lifelong learning, is an emerging research topic that has been attracting increasing interest in the field of machine learning. With human activity recognition (HAR) playing a key role in enabling numerous real-world applications, an essential step towards the long-term deployment of such recognition systems is to extend the activity model to dynamically adapt to changes in people's everyday behavior. Current research in continual learning applied to HAR domain is still under-explored with researchers exploring existing methods developed for computer vision in HAR. Moreover, analysis has so far focused on task-incremental or class-incremental learning paradigms where task boundaries are known. This impedes the applicability of such methods for real-world systems since data is presented in a randomly streaming fashion. To push this field forward, we build on recent advances in the area of continual machine learning and design a lifelong adaptive learning framework using Prototypical Networks, LAPNet-HAR, that processes sensor-based data streams in a task-free data-incremental fashion and mitigates catastrophic forgetting using experience replay and continual prototype adaptation. Online learning is further facilitated using contrastive loss to enforce inter-class separation. LAPNet-HAR is evaluated on 5 publicly available activity datasets in terms of the framework's ability to acquire new information while preserving previous knowledge. Our extensive empirical results demonstrate the effectiveness of LAPNet-HAR in task-free continual learning and uncover useful insights for future challenges.


TiSAT: Time Series Anomaly Transformer

arXiv.org Machine Learning

While anomaly detection in time series has been an active area of research for several years, most recent approaches employ an inadequate evaluation criterion leading to an inflated F1 score. We show that a rudimentary Random Guess method can outperform state-of-the-art detectors in terms of this popular but faulty evaluation criterion. In this work, we propose a proper evaluation metric that measures the timeliness and precision of detecting sequential anomalies. Moreover, most existing approaches are unable to capture temporal features from long sequences. Self-attention based approaches, such as transformers, have been demonstrated to be particularly efficient in capturing long-range dependencies while being computationally efficient during training and inference. We also propose an efficient transformer approach for anomaly detection in time series and extensively evaluate our proposed approach on several popular benchmark datasets.