Machine Learning - Winder.AI Blog

Industrial insight and articles from Winder.AI, focusing on the topic Machine Learning

Fast Time-Series Filters in Python

Fast Time-Series Filters in Python

Oct 2019, by phil-winder, in Machine Learning

Time-series (TS) filters are often used in digital signal processing for distributed acoustic sensing (DAS). The goal is to remove a subset of frequencies from a digitised TS signal. To filter a signal you must touch all of the data and perform a convolution. This is a slow process when you have a large amount of data. The purpose of this post is to investigate which filters are fastest in Python.

Scikit Learn to Pandas: Data types shouldn't be this hard

Feb 2019, by Phil Winder, in Machine Learning

Nearly everyone using Python for Data Science has used or is using the Pandas Data Analysis/Preprocessing library. It is as much of a mainstay as Scikit-Learn. Despite this, one continuing bugbear is the different core data types used by each: pandas.DataFrame and np.array. Wouldn’t it be great if we didn’t have to worry about converting DataFrames to numpy types and back again? Yes, it would. Step forward Scikit Pandas. Sklearn Pandas Sklearn Pandas, part of the Scikit Contrib package, adds some syntactic sugar to use Dataframes in sklearn pipelines and back again.

Principal Component Analysis

Jan 2018, in Machine Learning, Workshop

Dimensionality Reduction - Principal Component Analysis Welcome! This workshop is from Sign up to receive more free workshops, training and videos. Sometimes data has redundant dimensions. For example, when predicting weight from height data you would expect that information about their eye colour provides no predictive power. In this simple case we can simply remove that feature from the data. With more complex data it is usual to have combinations of features that provide predictive power.

101: Why Data Science?

Jan 2018, in Training, Machine Learning, Data Science

What is Data Science? Software Engineering, Maths, Automation, Data A.k.a: Machine Learning, AI, Big Data, etc. It’s current rise in popularity is due to more data and more computing power. For more information: Examples US Supermarket Giants Target: Optimising Marketing using customer spending data. Walmart: Predicting demand ahead of a natural disaster. Discovery Most projects are “Discovery Projects”.

102: How to do a Data Science Project

Jan 2018, in Training, Machine Learning, Data Science

Problems in Data Science Understanding the problem “the five-whys” Different questions dramatically effect the tools and techniques used to solve the problem. Data Science as a Process More Science than Engineering High risk High reward Difficult Unpredictable By Kenneth Jensen CC BY-SA 3.0, via Wikimedia Commons Impacts of Data Science What is the purpose of the project?

201: Basics and Terminology

Jan 2018, in Training, Machine Learning, Data Science

The ultimate goal First lets discuss what the goal is. What is the goal? The goal is to make a decision or a prediction Based upon what? Information How can we improve the quality of the decision or prediction? The quality of the solution is defined by the certainty represented by the information. Think about this for a moment. It’s a key insight. Think about your projects.

202: Segmentation For Classification

Jan 2018, in Training, Machine Learning

Segmentation So let’s walk through a very visual, intuitive example to help describe what all data science algorithms are trying to do. This will seem quite complicated if you’ve never done anything like this before. That’s ok! I want to do this to show you that all algorithms that you’ve every heard of have some very basic assumption of what they are trying to do. At the end of this, we will have completely derived one very important type of classifier.

203: Examples and Decision Trees

Jan 2018, in Training, Machine Learning

Example: Segmentation via Information Gain There’s a fairly famous dataset called the “mushroom dataset”. It describes whether mushrooms are edible or not, depending on an array of features. The nice thing about this dataset is that the features are all catagorical. So we can go through and segment the data for each value in a feature. This is some example data: poisonous cap-shape cap-surface cap-color bruises? p x s n t e x s y t e b s w t p x y w t e x s g f etc.

301: Data Engineering

Jan 2018, in Training, Machine Learning

Your job depends on your data The goal of this section is to: Talk about what data is and the context provided by your domain Discover how to massage data to produce the best results Find out how and where we can discover new data ??? If you have inadequate data you will not be able to succeed in any data science task. More generally, I want you to focus on your data.

302: How to Engineer Features

Jan 2018, in Training, Machine Learning

Engineering features You want to do this because: Reduces the number of features without losing information Better features than the original Make data more suitable for training ??? Another part of the data wrangling challenge is to create better features from current ones. Distribution/Model specific rescaling Most models expect normally distributed data. If you can, transform the data to be normal. Infer the distribution from the histogram (and confirm by fitting distributions)