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I frequently use OAC for my job in data analytics. It is an incredibly powerful tool allows you to create specialized reports and analyses of a large database and even create dynamic visualizations and custom dashboards to display and interact with your data all through a simple drag and drop interface. Having some SQL knowledge will allow you to modify your analyses further by creating custom formulas. I wouldn't expect anyone to have a personal use for this without a massive and complicated database, but having knowledge and experience with it could allow you to get a very good job in data analytics. This YouTube channel has multiple free tutorials that can make you a relatively advanced user in a very short period of time. These videos are literally the videos that some companies train their employees with.1 point
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Introduction Hi all! I wanted to take some time to put together a comprehensive privacy guide with the goal of offering viable solutions to common services and software that are privacy oriented. When determining my recommendations and suggestions, I am mostly utilizing the following criteria: Follows the GNU four freedoms Services not based in mandatory key disclosure jurisdictions Audited or transparent Motivation "That's great Wade, but I don't have anything to hide." This is a fallacy I would like to disrupt. Voluntarily giving information away is perfectly reasonable, so long as one understands the costs/benefits and risks. There are security considerations that many people fail to realize when they suggest that privacy is not important. Humans can be the greatest vulnerability and easiest way to gain unauthorized access to a system; simply knowing information, especially that people voluntarily provide or publicly make available, can be valuable in the information gathering phases of an attack. An attacker can use this information to social engineer you or people related to you, causing potential financial damage to you or those around you. Some in the intelligence community suggest that reducing privacy is a necessary cost for increasing security. I look at this differently. Strong privacy goes hand-in-hand with security. I will attempt to demonstrate this in a related thread, Twenty+ Reasons Why Mass Surveillance is Dangerous. In the meantime, you are welcome to view my original publication on Packet Storm Security titled, Twenty Reasons Why Mass Surveillance is Dangerous. Additional resources I'd like to recommend on why privacy is important, to support my motiviation: The Value of Privacy by Bruce Schneier When Did You First Realize the Importance of Privacy? by EFF The Little Book of Privacy by Mozilla Table of Contents ---- Providers -------- Cloud Hosting -------- DNS ------------ Resolvers ------------ Clients -------- Email ------------ Hosts ------------ Clients -------- Image Hosting -------- News Aggregation -------- Search Engines -------- Social Networks -------- Text Hosting (Pastebin) -------- Video Hosting -------- Web Hosting ---- Software -------- Calendars and Contacts -------- Chat -------- Document and Note Taking -------- Encryption -------- File Sharing -------- Metadata Removal -------- Password Managers -------- Web Browsers ------------ Browser Specific Tweaks ------------ Browser Specific Extensions ---- Operating Systems and Firmware -------- Desktop -------- Mobile -------- Routers I will update this thread and table of contents as the subsidiary topics are created.1 point
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I recently became very interested in the Mandelbrot set after watching some videos of "Mandelbrot zoom" which are some cool and trippy videos with an incredibly profound underlying mathematical meaning. There is a very good Numberphile video that explains what the Mandelbrot set is in plain English, but I'll also do my best to do a very quick summary here. The Mandelbrot set is the collection of all complex numbers (e.g. 1+i) denoted "c" which satisfy the condition that the function "Zn+1 = Zn^2 + c" where Z0=0 converges. In simpler terms that means that if you repeatedly square your result and add the original number then repeat infinitely many times then the answer is anything other than infinity. In the image above, the black region are areas where c converges and thus the function is stable, all other areas are unstable, and the different colors represent different degrees of instability (see chaos theory where a very infinitesimally small change in the original conditions has a drastic impact on the outcome). The reason this is so interesting is because of the shape of the Mandelbrot set itself. Not only is it a very interesting shape macroscopically, but it is a fractal and no matter how far you zoom in, it is infinitely complex, chaotic, and even recursive. The same macroscopic shape shows up repeatedly no matter how far you zoom in (though slightly distorted). I highly recommend viewing the Mandelbrot zoom video that I linked above, or any of the dozens more on YouTube. If you would like to get some very basic intuition for why the Mandelbrot set looks the way it does, you can use this interactive tool which shows you the behavior of complex numbers when you repeatedly square them. This will not explain the shape of the Mandelbrot set exactly, but it will show you how squaring a complex number is actually just a rotational transformation in the complex plane. Because of this, when you repeatedly square a complex number that is within the Mandelbrot set, it will go around in a circle over and over while converging upon a finite value. Although you can easily check whether a complex number is within the Mandelbrot set with a tool such as WolframAlpha, I decided to write a quick program which does that for myself. It works perfectly, but I must admit that it's slightly crude. The Mandelbrot set is bounded by a circle in the complex plane with radius 2, so any complex number which falls outside that circle is automatically not within it. However, if you choose a complex number that is within that circle, I believe it is theoretically possible that a future term will "bounce" outside the circle before coming back in and converging. An example that slightly shows what I mean is that 0.25 is in the Mandelbrot set, and the function converges to 0.5 so future terms are larger than the starting number but still converge. Similarly, it could be true that |(a,b)|<2 but |Zn|>2 for some n while a+bi still converges. Although this is possible, I can't imagine it being common or that numbers could bounce much further outside than 2. For that reason, I decided that I am reasonably certain no number will ever go outside the circle with radius 5, and thus if my program detects a term with real or imaginary component greater than 5 then c must not be within the Mandelbrot set. I have no proof that this is true, but like I said I am reasonably certain that it is. Additionally, my program only runs for the first 5000 terms because any number which does not converge should grow much much more quickly than that. Here is the code in Perl: #!/usr/bin/perl -w use strict; my($firstR, $firstI, $newR, $newI, $tempR); print "Enter the real portion of a complex number> "; chomp($firstR = <stdin>); print "Enter the imaginary portion of a complex number> "; chomp($firstI = <stdin>); $newR = $firstR; $newI = $firstI; for(my $i = 0; $i < 5000; $i++){ $tempR = $newR**2 - $newI**2 + $firstR; $newI = 2*$newR*$newI + $firstI; $newR = $tempR; if($newR>5 or $newI>5){ print "(".$firstR." + ".$firstI."i) is not in the Mandelbrot set.\n"; exit; } } print "(".$firstR." + ".$firstI."i) is in the Mandelbrot set!\n"; I hope you enjoyed this post and that you can now recognize the beauty of the Mandelbrot set.1 point
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