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A feature is a numeric representation of raw data. There are many ways to turn raw data into numeric measurements, which is why features can end up looking like a lot of things. Naturally,
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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Feature engineering is the process of formulating the most appropriate features given the data, the model, and the task.
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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Practitioners agree that the vast majority of time in building a machine learning pipeline is spent on feature engineering and data cleaning. Yet, despite its importance, the topic is rarely discussed on its own.
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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Mastery is about knowing precisely how something is done, having an intuition for the underlying principles, and integrating it into one’s existing web of knowledge. One does not become a master of something by simply reading a book, though a good book can open new doors.
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
.implementation .modelthinking mastery is contextual
Next, consider the scale of the features. What are the largest and the smallest values? Do they span several orders of magnitude? Models that are smooth functions of input features are sensitive to the scale of the input.
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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Each piece of data provides a small window into a limited aspect of reality. The collection of all of these observations gives us a picture of the whole. But the picture is messy because it is composed of a thousand little pieces, and there’s always measurement noise and missing pieces.
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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The first sanity check for numeric data is whether the magnitude matters. Do
Alice Zheng, Amanda Casari • Feature Engineering for Machine Learning
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The magnetic force is doing the spinning. Everything else is about getting the magnets in the right place with the right polarity; nature does the rest.
This is critical, so we’ll say it again. A combustion engine carries its fuel, which it burns, fighting thermodynamics by converting heat to motion, so it is less efficient. An electric motor
... See morePacky McCormick • The Electric Slide
Electric motors are one type of electric actuator (devices that convert electrical energy into mechanical motion). Actuators themselves are a subset of transducers or energy-conversion devices, which convert energy from one form to another.
The Electric Stack converts electricity into motion , but also into heat (induction stoves), into magnetic
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