Hypergeometric Distributions and Computational Solutions

I saw an interesting exam problem in my graduate level statistics exam.  What was particularly interesting was that we were given a problem that could not be solved with a calculator, or by obvious simplification methods.

For this, I am self publishing this document that describes an algorithmic approach to solving hypergeometric distributions that would be otherwise insoluble using conventional methods.  My software authored for this is accurate and is differentiated from Wolfram Mathematica or Alpha in that the method and code is open to academic scrutiny.

Here is that link: hypergeom.pdf

Homer Conferencing… Not ready for prime time

This is a lesson in vaporware.  Vaporware is a software or hardware solution that enters a high demand market without any actual viable solution.  Often times, they pretend to be professional, but through social media, they are actually heavily locked down information machines.

Characteristics?

  • Photoshopped images of the application running on a PC.  Be sure to notice the presence of a beautiful generic woman on a beach in the application window.
  • Facebook pages that are locked down to where negative feedback is tightly controlled.  Be sure to notice that they are the only ones that post of their page.
  • Mailing lists or support forums don’t exist.  Be sure to notice that buttons that subscribe you to a mailing list opens a webpage on a separate website that never finishes loading (times out).
  • If the software downloads, it will have enormous amounts of configuration choices that aren’t targeted towards the actual purpose of the software.  Be sure to notice video conferencing software that doesn’t have a “Add webcam” feature, but allows you to configure various nuances to how the application appears.
  • The software is ad sponsored and has no uninstall capability.  In this package, I haven’t noticed any ads just yet, but I’m waiting.  First though, I have to run it again and currently, I have no reason to.

I’m not sure why peer-to-peer video conferencing is such a magnet for these kinds of fluff projects.  It really shouldn’t be so hard to do.  The webcam and microphone are data streams.  You encode them into a streaming format (MPEG, WEBM, OGG, H.264 if you insist) and pipe them out to an IP address.  A little extra effort, you can even use a SIP protocol, but it isn’t necessary.

So here I have it installed, and I’m really wishing I had done a time machine backup immediately before installing…

How can a project like this be saved?  It takes honesty.  Create open and world viewable forums.  Yes, people will post bad things about your software, but make a show of working towards a solution.  Open up your social network sites and use them to recruit developers and users instead of information control marketing machines.

Don’t go the way of the Ekiga softphone of the late 2000’s.  They were the official softphone of Ubuntu linux that was included with their distribution.  Problem is that it never worked.  There was no improvement.  And by 2010, they were expelled from the distribution.  They’re still around, but I don’t dare install their product.  I simply don’t trust them with my limited hard disk space.

I look forward to a day that an free and open video conferencing software becomes a reality.  Then, we can truly divorce ourselves from the spooky usage licenses (and potential eavesdropping) from services such as Microsoft Skype, Google Hangouts, or Apple FaceTime.

Large Matrices in Microsoft Word 2010

Ever want to simply go beyond 3×3 matrices in the Microsoft Word 2010 Equation Editor?

Screen shot of Microsoft Word 2010 graphical interface.
You don’t have a lot of choices for dimensions of matrices.

It looks like 3×3 is as large as you can go, but you can go ‘under the hood’ to create matrices of arbitrary size by switching between “Linear” and “Professional” modes.

Let’s first create a 3×3 matrix and populate it.  It doesn’t have to be 3×3, but for sake of explanation, it makes a clearer example.

Screen shot of Microsoft Word 2010 graphical interface.
This is a 3×3 Matrix with all cells populated

Once you have the matrix complete. Click on the black arrow on the lower right-hand corner of the Equation Editor.  This pull-down window selects between Professional and Linear modes.  Click on Linear.

Screen shot of Microsoft Word 2010 graphical interface.
Select Linear Mode

You will see your equation editor change the layout of the equations into a textual form.  You can think of this as a markup language for the matrix editor.

Screen shot of Microsoft Word 2010 graphical interface.
Textual mode of the equation editor.

The ampersand symbols delimit the columns and the at symbols delimit the rows.  If you have an incomplete entry of a row or column, the equation editor will try to make it complete.

Screen shot of Microsoft Word 2010 graphical interface.
A larger matrix created and fully populated to resembler a DTMF key arrangement.

At this point, go back to your menu and switch back to professional to view your new matrix.

Screen shot of Microsoft Word 2010 graphical interface.
A complete 4×4 matrix with all cells populated

And there you have it.  A hand-made 4×4 matrix in Equation Editor for Microsoft Word 2010.

The surprising rediscoveries of Dr. John Vetter Burkardt

As I create my Interactive Resume, I remember stories of working with some of these amazing people.  Dr. Burkardt is one of those people.  He is a living treasure for his mathematical and computational knowledge.  Even the content of his webpage leads people to suspect this fact.

And here is what is surprising about it.  Sometimes I get curious and ask search engine a question.  It’s easier that way and often times faster than finding a human to ask.  Could be how to spell a word, or looking up a numerical algorithm.

Dr. Burkardt is notable in that twice his web site has come up in a list of google results that I clicked on, only then to discover I was on the page of a person whom I previously had worked for.  And yes, his pages have a 100% rate of having the answer I seek.  So far, the rate is about once in every 5 years this happens.

Check out his site below.  It looks small, but it is in fact quite huge; it only looks small due to it’s tight organization.  This site represents a lifetime of publicly accessible work this brilliant mind has worked on.

http://people.sc.fsu.edu/~jburkardt/

Servicing a dry bearing

At my father’s house today and I heard the heat pump chirping occasionally. To me, that is the sound of lubrication failure and an early state of electric motor failure. As compressors are hermetically sealed and lubricated, I was almost certain the culprit was the blower motor.

I opened up the unit and saw the blade still spun freely, a good sign. After shutting the breaker, I disconnected the compressor and powered the heat pump back up. The fan ran for about 30 seconds and started chirping again.

I proceeded to remove the motor. It is a 48Y frame 1/4 horsepower single phase motor made in 1989 by General Electric. Looking up the cost of this motor to be $160-180 in the 60C ambient temperature spec (the 40C was $60 cheaper, but would fail soon). Given the expense, I decided to experiment with servicing it.

Loosened the set screw to remove the blade. The motor has 4 long screws/nuts that hold the motor together and they were removed.  With a screwdriver, I carefully prayed the pot metal caps off each end. The armature slid out of the stator and gave access to the two sleeve bearings. I lubricated them with a grease that was convenient, but a heavy gear oil probably would have been more appropriate.

I reassembled the motor and electronically attached it to the heat pump circuit.  I decided to let it run for a while to see how it performs.  After about 30 minutes, it was warm, but silent, so I decided to end the test with a declaration of success.

The heat pump was mechanically and electrically reassembled and seems to be performing well with fresh lubrication.

Anybody curious what NEMA frames are, I attached a chart.

http://www.motorsanddrives.com/cowern/motorterms2_chart.html

On the Home Depot e-mail hack

53,000,000 e-mails.  Amounts to about 1/6 the population the United States.  Now I can’t imagine every one of those being valid.  I will confess that on occasions where I was pressed for an e-mail address, I simply made one up for the sake of moving right along without arguing with the cashier.

There are occasions where I simply can’t get away with posting bogus data.  Let’s say with Amazon, Google, Facebook, the e-mail address is an important part of your identity, and in many cases, my actual login ID.  What if one of the big guys gets hacked, or an unscrupulous employee collects and sells the data and retires in southern Snoozebeckistan?  The is a preventative measure.

I own my own domain.  Your sitting here and reading it.  No one knows of any specific e-mail address for me. One of the perks of owning my own domain is a have total control over the email addresses on my server.  I have an e-mail for each service I subscribe too, such as f@timothylegg.com for Facebook or g@timothylegg.com for all things Google.  These addresses simply alias and to a common local address that I receive mail from directly.

So yeah, some place that verifies over e-mail before creating an account, I create a special address just for them and have it delivered to my inbox.  Sometimes you find out who got hacked or sells out when I start getting Canadian Pharmacy or Russian Singles emails and that’s a bonus.  To fix it,  just rename the e-mail address and let them try to get it again.

Going wide with your e-mail addresses is the best spam filter.  They have to find it, and then after that, send me enough junk mail to where it’s worth changing my address.  I typically change my address every three or four years and have been quite fortunate.  In all of 2014, I have only gotten about 15 spam messages.

You want to send me a message on e-mail, just go to my website and look it up.  It’s current and fresh.  You know where to find me.

How safe is that old car?

Every now and then, you find something on youtube that is so fascinating that you can’t help share it with everybody you know.  You play the video, pause it, and ask yourself, “How is this going to turn out?”

A few years back, the IIHS celebrated their 50th anniversary by crash testing two cars for a direct comparison of the technologies of restraint systems and energy-absorbing crumple zones.  The subjects of this test were both Chevrolet makes: a 2009 Malibu and a 1959 Bel Air.

The outcome of the test will surprise many people, excluding a few trained engineers whom daydream about types of destructive evaluation experiments.  If you haven’t searched it out already, hit up the youtube link that I selected as being the most comprehensive.

A number of social changes occurred during this time to make safety  profitable for automakers.  The deaths of Jayne Mansfield and James Dean were catalysts and culminated with the best selling book Unsafe At Any Speed by Ralph Nader.