Josh Kaplan

Arbitrarily Deletable Primes 03 Sep 2018

I recently watched this video about left-truncatable primes. A left-truncatable prime is a prime number that, when any number of left-most digits are removed, results in another prime number [1, 2, 3, 4]. The video also discussed right-truncatable primes, which are primes that when truncated from the right result in other primes and deletable primes,... read more.

Navigation: Using Local Noon to Find Position 01 Jan 2018

I was messing around with a fun navigation problem the other day and thought I’d share it. I was scrolling through a weather app on my phone when I came across the sunrise and sunset times and wanted to try calculating my longitude from these times. Determining Local Noon I started with sunrise and sunset... read more.

Minus Forty - A Useful Number for Temperature Conversion 28 Dec 2017

Most of us know that 32 degrees Fahrenheit is the temperature at which water freezes. We also know that this correlates to 0 degrees Celsius. But for many of us, our knowledge stops there and to convert between the two scales we must resort to either looking it up using some sort of app or... read more.

Newton’s Method: An Overview 12 Sep 2017

I was first exposed to Newton’s Method in my undergraduate numerical methods course. I’ve used it a number of times since then in undergraduate and graduate courses, but I didn’t begin to gain an appreciation for its power until my recent navigation systems course. To take a take a dive into Newton’s Method and deepen... read more.

Useful Technical Resources 04 Sep 2017

I wanted to put together a collection of engineering and technical resources. I’ll make this post an ongoing project and update it as I find new things. For now, I’ll post an initial list of resources I’ve used and I’ll add more as I remember or discover them. Mathematics Software Engineering / Computer Science Python... read more.

Accuracy of Newtonian Kinetic Energy in a Relativistic World 11 Jun 2017

One of my homework problems for my modern physics course asked me to calculate the highest velocity of a particle for which the Newtonian approximation of kinetic energy is accurate to within an error of of the actual, relativistic, kinetic energy. In trying to solve this problem, I decided it would be faster and easier... read more.

The Bare Minimum: Arduino 30 May 2017

As an undergraduate, I remember many occasions where I needed to become proficient in a topic as a step to achieving some further goal. It still happens to me today and I see it happening to my students. This post on Arduino is for people in that situation. You need to build the skill, but... read more.

Python List Comprehensions 08 Jan 2017

My absolute favorite feature of Python is lists. An elegantly dynamic data structure with a beautiful syntax. Everything from negative step indexing to their use as iterators makes Python lists, and therefore Python, the easiest solution to so many problems. One of the less obvious, but extremely powerful features of Python lists are list comprehensions.... read more.

My Collection of Notes 08 Jan 2017

Today, I am starting a new section on my site: Notes. This is a collection of my notes from various courses and topics I’ve studied. My goal with this is to create a digital copy of my notes to make it easier to store and access as well as, if people find it useful, to... read more.

Bash Tips and Tricks #2 - GREP 05 Jan 2017

This is my second post with a handful of pastable commands to improve your use of Bash. If you haven’t seen the first post, you can check it out here. This one is all about GREP. the GNU Regular Expression Parser. A command line utility that has nearly infinite uses and applications. Pastable #1 Grep... read more.

Bash Tips and Tricks - 10 Pastables to Make Things Easier 10 Dec 2016

Let’s talk about Bash. The command line shell used by default on Linux and Mac OS. This is not an introduction. This is not a tutorial. This is a collection of pastable commands that I’ve found useful. Pastable #1 Renames a all files in the current directory. for f in *; do mv $f $f.backup;... read more.

Control Systems with Kerbal Space Program 31 Jul 2016

Kerbal Space Program If you’ve never played the game and are even remotely interested in engineering, physics, or space stuff, you should try Kerbal Space Program (KSP) immediately. It’ll set you back a one time fee of $40 (at the time of this writing), but you’ll get many hours of entertainment out of it. Why... read more.

AWS to GitHub Migration 31 Jul 2016

The Problem I felt the need to move my website from Amazon Web Services (AWS) to something else for a while now for a number of reasons. First, my AWS server is costing me $15/mo and I’m not using it for anything other than hosting my website. At first I tried to convince myself I... read more.

Electron, Getting Started 12 Jun 2016

What is Electron? Electron is a framework for running Node.js applications on the desktop. This allows you to quickly write simple cross-platform GUI applications. This post details my experience getting started with electron. It’s built by GitHub and used to build their Atom text editor. Electron is also used to create a lot of other... read more.

Welcome to My Blog! 31 Dec 2015

Welcome and happy New Year! This is my blog. Here I’ll post all sorts of things I find interesting from engineering and computer science to leadership, management, and business development. I am an engineer and a passionate problem solver. Whether those problems are technical, business focused, or something else entirely, I enjoy tackling unique and... read more.