Next time someone says that we need safer programming languages because bugs in critical systems could kill people... (Mechanizing Proof https://mitpress.mit.edu/books/mechanizing-proof …)pic.twitter.com/Vi7TZ3HDOU
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It sounds like there is quite a lot of things to explore! Even checking that values are in "typical ranges" can probably prevent many errors.
Historical trend analysis can also help determine what is unusual, notable, etc., and offer automated advice or alerts. There's no reason ad sellers should be the only ones to benefit from historic data while users are left helpless.
For a GUI, you can check color contrast, absolute and relative sizes of fonts and text or graphical elements, etc. — make sure that all information is visible or scrollable, that there is no blinking or any change too rapid or out of the user's control, etc.
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