Reminder: Software blog

November 23rd, 2015

I don’t get around to updating this blog very much, as I’ve converted it away from technical topics so what’s left is my unfrequent rambling. If you’re interested in the technical topics, be sure to check out the other blog:

Time Zone Calculator

September 18th, 2015

I’m terrible with remembering which way to go when doing time zone conversions in my head (and paranoid that I got the answer right, because it’s usually interacting with a customer, so I don’t want to sound like an idiot).

Obviously there are a lot of time zone converter tools out there, but I like this one because the visual slider.


September 23rd, 2011

I haven’t posted in forever, but in case you missed it, Katy and I have a pet pig named Hamlet.

Let’s hit all the questions we normally get:

Because we wanted a pet that was litter box trainable and I’m allergic to cats. We don’t want to feel like we have to be home right after work to let a dog out. Also I don’t want something that I feel that I Read the rest of this entry »

No, the computer is locked.

December 8th, 2010

I had a weird encounter today at work with DSG (our desktop support group). A DSG worker came by to work on a colleague’s computer while the colleague wasn’t there. At first he asked if he knew where he was and when he would be back. I didn’t. As the DSG worker was going to be checking for malware, I suggested that he just log in and run a scan. The conversation went something like this:

Me: Why don’t you log in and just start running the scan.

DSG: I can’t the screen is locked.

Me: I don’t think it’s locked. This is a login screen. I think you can log in.

DSG: Sure, I could login with elevated credentials, but then he would lose any unsaved work.

Me: He won’t lose anything, this is a login screen.

DSG: No, it’s locked.

Me: (pointing no monitor) This is a login screen.

DSG: No, it’s a lock screen.

Me: (pressing ctrl-alt-del get past initial screen to show login form) This is a login screen…

DSG: No, it’s a lock screen (walks away)

This was interesting for me for two reasons. One, it kind of scares me that these are the people taking care of our computers; and two, I was completely dumfounded. For those who know me, I enjoy a good argument, but for some reason this was like walking into a brick wall. I’ve never seen anyone so blatantly deny what is right in front of their face. I guess I learned a new argument technique: arguing by aggressively denying reality.

Twin Cities Startup Weekend

November 25th, 2010

Last weekend I participated in the second Twin Cities Startup Weekend. You can read about the format on their site, but I pitched an idea (Choosely) on Friday that was voted in, and led a team that worked on launching the idea over the course of the weekend. is a tool for friends to plan activities. I helps groups take suggestions for what to do, and then vote on the final decision.

The startup weekend was a great experience. We got a working prototype off the ground and presented the concept to a panel of judges. We didn’t win, but it was really cool just to be on stage. You can read more about the weekend and all the teams on

Just a word of warning, while you can see the prototype, it’s not anywhere close to ready for prime time, so don’t judge too harshly.

Christmas Letter 2009

January 10th, 2010

In my ever-promt style, our Christmas letter is available here. I’ve also posted the collection of past letters here.

Wolfram|Alpha Easter Eggs

May 17th, 2009

Here is an interesting list of Wolfram|Alpha easter eggs. One that it failed to mention was “how many pickled peppers did peter piper pick?” A second list is available here.

Dumb Ideas II – Inferring Traffic From Cell Phones

April 15th, 2009

Have you ever been driving down the interstate and you come up to a car driving 10 mph under the speed limit in the left lane? You try all your favorite hand signals but this person just doesn’t figure out that they are holding people up. Ah yes, the driving-cell-phone-talker. Studies are showing that people have similar reaction times to drunk drivers when talking on cell phones while driving. But what if we could harvest a social good from the behavior?

Nearly everyone has a cell phone with them all the time. If you were to go down the street and take a survey 80%* of Americans own a cell phone, and the other 20% is in diapers or was alive to see the inauguration of FDR (or both). The percentage among people who comprise rush hour traffic is even higher. Why can’t we use this vast data source to figure out what’s going on with traffic without adding additional infrastructure costs?

First a quick introduction on how cell phones work:
Your cell phone is a small, digital radio transmitter. Cell phone towers scattered throughout the city are what allow your phone to get a signal. There are a lot of these towers, as the phone needs to be within 2 miles of a tower to communicate. So when a carrier is telling you that they have more bars in more places they are bragging that they have a higher tower density (or feeding you a line of marketing bull)**. Even when you are not talking on the phone, you cell phone periodically sends a signal to the towers that can hear it to register itself with that particular tower or towers. This registration is tracked on the carrier’s network so that if you receive and incoming call, the system will know which towers to use to attempt to communicate with your phone. Without this, the incoming call would have to be sent over all towers all over the country, which obviously isn’t efficient. When you are actually on a call, your phone is in continuous communication with the tower to transmit and receive data.

Now on to how this information can be used to track traffic flow. Because the carrier’s network is receiving periodic updates from your phone, regardless of if you are in a call or not, the system can track an approximate location for your phone. At worst, it could track if you are moving from tower to tower at a regular speed, implying that you are in a moving vehicle traveling at a reasonable speed. Your position can be calculated even more accurately, however, as your phone will most likely be able to reach several towers from the same position. The relative time at which the signals are received by the towers (or the relative strength of the signal received by the towers) can be used to triangulate your position***. This is how phones without GPS built in can still triangulate their approximate position (e.g. the first gen iPhone).

inferring traffic from cell phones

The data from one phone is not going to be accurate enough to accurately predict uniform movement, but when you aggregate hundreds or thousands of phones in the area, plus use the known locations of roads as an assumed path when positioning moving phones, you should be able to reconstruct traffic flow on large roads with reasonable accuracy.

There are other ways of using information coming from the vehicles to determine traffic. One approach suggests using smart phones with GPS to track traffic, but this approach requires an opt-in for users having software on their phones to help the process. Constantly running your GPS in the phone also hurts battery life. Another approach already in use is to have in-car GPS units transmit their position data back to a central system via the cell phone network. This can work, but there needs to be enough cars using the GPS driving aids to be accurate in an area. With this approach you also have the problems where the data coming back is likely to be only fed to users of that service (e.g. TomTom users get data from other TomTom systems, but don’t share with the Magellan users).

With raw data from the cell network, you don’t run into these problems. The cell phone carriers aren’t in the business of selling driving optimization devices, so they are likely to be willing to sell data to municipalities to be made generally available. Phone battery life won’t be affected because cell phones need to talk to the towers at regular intervals anyway. Users don’t need to opt in so there is an endless stream of data readily available as soon as someone throws the switch.

There are even more advantages to this approach. For rural areas where it wouldn’t make sense to track traffic using traditional means, one could use this approach to detect traffic congestion in areas where you wouldn’t normally monitor for it. For example, during the summer construction season, such a system could detect slowdowns anywhere in the country without requiring construction data to be entered by each individual state or city.


Cow-collision traffic jams automatically detected!!

To take the idea a step in the direction of Big Brother, the data could be used for long term transportation infrastructure planning. By understanding how people are flowing from one area of a city to another at various times of the day, one could better understand how to improve roads to make transportation more efficient.

There are many ways the above technique for the real time monitoring of traffic flow could be used. The big benefit of the approach is that no additional infrastructure is required, and users are not required to have special phones or software installed on their phones. The system just takes existing data and uses it for something useful.

* I reserve the right to make up, or use unreliable sources for my statistics.

** Or they could be arguing that their wireless frequency penetrates buildings better.

*** With three towers, you can get an exact position; with two a line, etc.

Dumb Ideas, I

March 26th, 2009

People who spend a lot of time around me quickly learn that I’m always observing silly little problems in the world and coming up with solutions. The observations and solutions are usually pretty good (my opinion, not necessarily what my friends think), but I am never in a position to affect the problem and so I end up just repeating the same rant every time we encounter it. To give everyone around me a break, I’m just going to clog up the tubes with my rants in this blog series and let my friends go on in peace.

First on the block is coffee lids. I’m talking those that you get at your cookie-cutter coffee shops (maybe others) like Starbucks and Caribou. Consider the cup & lid pictured below.

The problem here is the mouth piece. It’s designed to channel liquid out the opening. This may sound like a good idea, being that you’re going to drink out of this device, and getting liquid out is one of your primary goals, but my problem is that when I walk, the act of walking shifts the liquid in glass. Maybe it’s just me, but my stride seems to be able to cause constructive interference in a large Starbucks glass that amplifies the wave until it splashes out.

This invariably results in me burning my hand.

My proposed improvement to the lid is something like this:

This is a little hard to illustrate with my limited drawing abilities (AutoCADers out there, by all means, please lend a hand). The basic idea is that there is an indentation just below the opening to the lid so that splashing liquid will get redirected against the plastic of the lid as opposed to out of the cup).

With this design, liquid is still free to escape the cup when the cup is tilted, but the action of a quick splash is unlikely to have liquid leave the cup, and if it does, it won’t leave with much velocity to burn my hand.

I don’t think the change would add much to the production costs of the lid, and I think it could be done without affecting stability. But who knows, it’s just a dumb idea…

Econ in Action

March 13th, 2009

I saw the following sign at a gas station today:

It’s good to know the basic principles of microeconomics are still alive and well despite the crazy financial world.

As a refresher, no matter whether the government taxes the consumer or the producer, the tax burden will be split between the consumer and producer in a way that reflects the price elasticity of demand. I think we can guess how elastic the demand for cigarettes is, hence the buyer is paying most of the taxes.