Category Archives: Math

Visual Recall Devices for Electrodynamics formulas

Ingenious use of hand shapes to recall the structure of formulas in Electrodynamics. The kernal of this wisdom is that the hand is one of the few “devices” that must be allowed in any testing situation for students. Yes, I know there is an iPhone app for each formula that plots in 3D, etc. But what if you had solve these equations after a ship wreck?

Visual recall for physics (electrodynamics) formulas (equations)

Coordinate Transformation Rules

When I was a kid it took me a long time to learn this.  So, I thought it would useful to put a link to it here.  The transformations are from rectangular to polar, cylindrical and back in a useful structured approach.

This is a link to Dan Fleisch’s site for his book.  He is an Associate Professor in the Department of Physics at Wittenberg University, where he specializes in electromagnetics and space physics.  He is the author of A Student’s Guide to Maxwell’s Equations published by Cambridge University Press in 2008


Coordinate transformation rules PDF



Where does Big Data come from?

Searching for all green technical images, I found this one.

Where does big data come from?
How are they getting all this data?










Some of the many sources for online data collection going on every second, 24/7, every day:

  1. Surfed several websites gathering info for a presentation – My connectivity provider (Sprint) and Google added more info about me inside their already significant repositories
  2. Paid a few bills online – Credit card companies not only have my original transactions and buying habits but now they know my payment tendencies as well
  3. Downloaded a movie from iTunes for my trip – Apple adds this to the profile I have been populating for almost a decade
  4. Called my wife from my mobile phone to her car phone – Sprint and OnStar just got some more info about usage time and calling locations
  5. Printed boarding passes for a flight – Southwest knows where I have been, where I’m going and my general flight patterns.
  6. Drove to the airport – Sprint knows roughly the path I took from Home to the airport via my mobile phone switching between cell towers.
  7. Browsed email and some apps on my iPad – Apple and who knows what app developers just gathered access and some location data
  8. Landed in Los Angeles, El Paso & Dallas – Phone turned on at every stop and has tracked some level of information on my location and calls.
  9. Got into rented car and drove to meeting site – Hertz captures the location, type of car, duration etc. Plus Sprint knows roughly where I’m at too.
  10. Checked into room and had dinner – The hotel and credit card companies have that covered and logged.
  11. Browsed a few websites, email and writing an article – The hotel network and connectivity provider logged everyone of them, I promise.Read more here

Astronomy Needs “Forecast Transparency” for Observatories

There is an interesting visualization of forecast transparency and using atmospheric data here. Science is usually my inspiration for both calculating metrics and visualizing them for business. Sometimes though, the business data needs to be more summarized, and less accurate, more simplified, and have some of the statistics removed….

There is an interesting contrast when comparing this to the concept of Business forecast transparency. In business parlance, Forecast is future revenue and future earnings; not future weather. Transparency means that external people (usually analysts) can see how the metric (in this case Forecast) was derived. The formula and source data (or leading indicators). In the case of Astronomy, the transparency refers to the visibility through the atmosphere.