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 Statistical Learning


Linear Regression in Python

#artificialintelligence

In Linear Regression (LR) we used one independent variable for prediction. In Multiple Linear Regression (MLR) we used multiple independent variable for prediction. So, with the help of above code we can implement Linear Regression on our data.


Gradient descent for linear regression using Golang - Backlog

#artificialintelligence

I recently decided to dive into machine learning, a field I have wanted to understand for a long time but have never had the time to pursue. I've been taking the free (and amazing!) course from Stanford University's Andrew Ng on Coursera. The first two weeks are dedicated to the Linear Gradient algorithm. In this post, I'll provide an overview of how it works and share how I implemented the vectorized version and parts of the non-vectorized version in Golang using the gonum library. Linear regression is a technique used in modeling the linear relationship between an input and its output.


Data Scientist ai-jobs.net

#artificialintelligence

Healthcare organizations and technology vendors connect to Redox once, then authorize what data they send to and receive from partners through a centralized hub. Redox's cloud-based platform is vendor and standards agnostic and enables the secure and efficient exchange of healthcare data. This approach eradicates the need for point-to-point integrations and accelerates the discovery, adoption, and distribution of patient and provider-facing technology solutions. With hundreds of healthcare organizations and technology vendors exchanging data today, Redox represents the largest interoperable network in healthcare. Learn how you can leverage the Redox platform at www.redoxengine.com.


Active Learning in Video Tracking

arXiv.org Machine Learning

Active learning methods, like uncertainty sampling, combined with probabilistic prediction techniques have achieved success in various problems like image classification and text classification. For more complex multivariate prediction tasks, the relationships between labels play an important role in designing structured classifiers with better performance. However, computational time complexity limits prevalent probabilistic methods from effectively supporting active learning. Specifically, while non-probabilistic methods based on structured support vector machines can be tractably applied to predicting bipartite matchings, conditional random fields are intractable for these structures. We propose an adversarial approach for active learning with structured prediction domains that is tractable for matching. We evaluate this approach algorithmically in an important structured prediction problems: object tracking in videos. We demonstrate better accuracy and computational efficiency for our proposed method.


Privacy-Preserving Public Release of Datasets for Support Vector Machine Classification

arXiv.org Machine Learning

We consider the problem of publicly releasing a dataset for support vector machine classification while not infringing on the privacy of data subjects (i.e., individuals whose private information is stored in the dataset). The dataset is systematically obfuscated using an additive noise for privacy protection. Motivated by the Cramer-Rao bound, inverse of the trace of the Fisher information matrix is used as a measure of the privacy. Conditions are established for ensuring that the classifier extracted from the original dataset and the obfuscated one are close to each other (capturing the utility). The optimal noise distribution is determined by maximizing a weighted sum of the measures of privacy and utility. The optimal privacy-preserving noise is proved to achieve local differential privacy. The results are generalized to a broader class of optimization-based supervised machine learning algorithms. Applicability of the methodology is demonstrated on multiple datasets.


Knowledge-Induced Learning with Adaptive Sampling Variational Autoencoders for Open Set Fault Diagnostics

arXiv.org Machine Learning

The recent increase in the availability of system condition monitoring data has lead to increases in the use of data-driven approaches for fault diagnostics. The accuracy of the fault detection and classification using these approaches is generally good when abundant labelled data on healthy and faulty system conditions exists and the diagnosis problem is formulated as a supervised learning task, i.e. supervised fault diagnosis. It is, however, relatively common in real situations that only a small fraction of the system condition monitoring data are labeled as healthy and the rest is unlabeled due to the uncertainty of the number and type of faults that may occur. In this case, supervised fault diagnosis performs poorly. Fault diagnosis with an unknown number and nature of faults is an open set learning problem where the knowledge of the faulty system is incomplete during training and the number and extent of the faults, of different types, can evolve during testing. In this paper, we propose to formulate the open set diagnostics problem as a semi-supervised learning problem and we demonstrate how it can be solved using a knowledge-induced learning approach with adaptive sampling variational autoencoders (KIL-AdaVAE) in combination with a one-class classifier. The fault detection and segmentation capability of the proposed method is demonstrated on a simulated case study using the Advanced Geared Turbofan 30000 (AGTF30) dynamical model under real flight conditions and induced faults of 17 fault types. The performance of the method is compared to the different learning strategies (supervised learning, supervised learning with embedding and semi-supervised learning) and deep learning algorithms. The results demonstrate that the proposed method is able to significantly outperform all other tested methods in terms of fault detection and fault segmentation.


Hour-Ahead Load Forecasting Using AMI Data

arXiv.org Machine Learning

Accurate short-term load forecasting is essential for efficient operation of the power sector. Predicting load at a fine granularity such as individual households or buildings is challenging due to higher volatility and uncertainty in the load. In aggregate loads such as at grids level, the inherent stochasticity and fluctuations are averaged-out, the problem becomes substantially easier. We propose an approach for short-term load forecasting at individual consumers (households) level, called {\em Forecasting using Matrix Factorization} (\textsc{FMF}). \textsc{FMF} does not use any consumers' demographic or activity patterns information. Therefore, it can be applied to any locality with the readily available smart meters and weather data. We perform extensive experiments on three benchmark datasets and demonstrate that \textsc{FMF} significantly outperforms the computationally expensive state-of-the-art methods for this problem. We achieve up to $26.5 \%$ and $24.4 \%$ improvement in \textsc{RMSE} over Regression Tree and Support Vector Machine, respectively and up to $36 \%$ and $73.2 \%$ improvement in \textsc{MAPE} over Random Forest and Long Short-Term Memory neural network, respectively.


Measuring group-separability in geometrical space for evaluation of pattern recognition and embedding algorithms

arXiv.org Artificial Intelligence

Evaluating data separation in a geometrical space is fundamental for pattern recognition. A plethora of dimensionality reduction (DR) algorithms have been developed in order to reveal the emergence of geometrical patterns in a low dimensional visible representation space, in which high-dimensional samples similarities are approximated by geometrical distances. However, statistical measures to evaluate directly in the low dimensional geometrical space the sample group separability attaiend by these DR algorithms are missing. Certainly, these separability measures could be used both to compare algorithms performance and to tune algorithms parameters. Here, we propose three statistical measures (named as PSI-ROC, PSI-PR, and PSI-P) that have origin from the Projection Separability (PS) rationale introduced in this study, which is expressly designed to assess group separability of data samples in a geometrical space. Traditional cluster validity indices (CVIs) might be applied in this context but they show limitations because they are not specifically tailored for DR. Our PS measures are compared to six baseline cluster validity indices, using five non-linear datasets and six different DR algorithms. The results provide clear evidence that statistical-based measures based on PS rationale are more accurate than CVIs and can be adopted to control the tuning of parameter-dependent DR algorithms.


Breaking down the agglomerative clustering process

#artificialintelligence

In machine learning, unsupervised learning is a machine learning model that infers the data pattern without any guidance or label. Many models are included in the unsupervised learning family, but one of my favorite models is Agglomerative Clustering. Agglomerative Clustering or bottom-up clustering essentially started from an individual cluster (each data point is considered as an individual cluster, also called leaf), then every cluster calculates their distance with each other. The two clusters with the shortest distance with each other would merge creating what we called node. Newly formed clusters once again calculating the member of their cluster distance with another cluster outside of their cluster.


Predicting marketing performance with Machine Learning

#artificialintelligence

It's difficult for companies to judge how a marketing campaign has performed in the past never mind predicting how one will perform in the future. This becomes increasingly more difficult when multiple types of campaigns are ran over the same period, different products are available or unexpected outside factors influence user behaviour. In this project I will attempt, using multiple machine learning models, to judge how marketing campaigns have performed and predict how they will perform in the future. For the modelling I will be using a synthetic dataset containing information on Starbucks members over a month long period. Due to small size of this dataset there are a number of limitations with the data that I will outline later in this post.