Tutor profile: Richard H.
Subject: Web Development
How are modern websites built?
Subject: Machine Learning
What is a basic example of machine learning?
While machine learning is often made to sound very complicated, its most basic tasks are similar, or identical, to basic tasks in statistical modeling. A very basic task (at least these days) is image classification, where a model can learn to label certain types of images. You might, for instance, want to know what kind of flower is in a picture you took at the park. To do this, researchers will find a "dataset", which is a collection of relevant samples, of flowers and label them, according to their correct genus and/or species. Then with a little bit of linear algebra, they create a model that is initialized with some random parameters (or weights, as they are called in machine learning). These parameters can be connected to a second, smaller set of parameters. The first set "feeds" into the next set, which means that they undergo a matrix transformation that concatenates them to a smaller size, perhaps representing the number of potential classifications. They can use any number of error equations, which takes the input and the output and determines how well the model is doing, to come up with a "loss". Using high school calculus, they modify the parameters of each layer to either strengthen correct responses or discourage incorrect ones. This is also known as multivariate regression or logistic regression. If you do that enough times, you have a model that can accurately predict the species of flower based only on a photo you provide! Obviously, some of the nitty gritty details are missing here, but most of those details are handled for you by modern machine learning libraries. Understand the broader concepts, and you can implement the models.
Subject: Computer Science (General)
What is a function?
In computer programming, a function is a procedure that can be specified and used at will. What that means, in layman's terms, is it allows you to store a block of instructions in memory and execute those instructions at any point during your program. Functions are an essential building block of most modern programming language and can even be extended to an entire programming paradigm, called "functional programming". Unlike mathematical functions, which define relations between an input and an output, computer functions don't necessarily need either. Depending on the programming language, functions can execute a set of instructions without inputs or outputs, define relations between an input and an output, or both. Also depending on the language is whether or not functions exist in their own "scope", which means whether or not they can have "side effects": actions modify parts of the program outside of the function. Some languages let you do this, while others do not.
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