Piggy's Blog

Ramblings from the tech to human world and back

Letter to 10 year old self

Dear Francesco, It’s me, 25 years in the future. Can you please stop typing on that keyboard and listen? Let me give you some advice about your life. I know, it’s annoying to let people think you are a weirdo just because you don’t play the way “regular” kids do. But don’t let that stress you. Things will fall into place at some point, believe me. After all, I am writing to you from a keyboard that makes exactly the...
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What data analytics pipelines should have

Big data analytics not only means crunching algorithms over high dimensional data for weeks. It also means preparing the data to get processes with more or less standard tools. A common pipeline that every data scientist should follow is reported below. Order of operations matters, even though for some special cases some can be anticipated or postponed. Here are five steps that a good analytic pipeline should include. Below this list, an infographic shows the steps of a good analytic pipeline...
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Adding identity to ssh-agent

One of the most annoying aspects of security is The password. Even more so every time the Linux console gently asks it a number of times. Whenever this occurs once per minute, it gets tiring. Those who are dealing with ssh sessions that need authentication, should know about a way to authenticate once and be safe for the rest of the day (provided no reboot occurs). All of this goes under the name of ssh identity, namely, if we let ssh...
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Stability of stochastic gradient descent

A paper that, in my opinion, will be more influential than the garbage constantly published on many paid journals, is “Train faster, generalize better: Stability of stochastic gradient descent”, written by Moritz Hardt at Google. The authors published it on Arxiv, from where it can be downloaded for free. In the aforementioned paper, the stability of stochastic gradient descent, SGD, is formally proved for convex, non-convex L-Lipschitz loss functions. That basically means that SGD is guaranteed to be stable under certain assumptions....
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Kernel mode hooking, good features getting rotten

Disclaimer This article should be read with the sole purpose of education. __No users nor machines must be hurt or damaged. Ethics first. Fun later. Modern x86 Operating Systems, use protected mode to execute instructions. In protected mode there are 4 different privilege levels, from 0 to 3. They are also referred to as ring0 - ring3, to indicate the level of separation between them. The highest-level (the least privileged) is userland (ring3) where regular applications run. The lowest-level (the highest privileged) is...
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