Sean Zehnder's Blog

ITunes U - Stanford Technology Ventures Program

Thu, 13 Mar 2008 12:07:02 -0800

My friend Dave tipped me off to a great series on ITunes U -- the Stanford Technology Ventures Program. It has a wonderful set of lectures by various high-tech entrepreneurs mostly from Silicon Valley. As I'm in the process of launching a company, I'm amazed by how relevant the insight of these repeat entrepreneurs can be. I'm recalling how this type of lecture used to sound trite and self-important back in school when I had no notion about what it takes to run a business. Now, however, it feels urgent and relevant because so much of starting a business seems to be about trusting yourself and others -- about escalating commitment while managing risk. It's not the type of knowledge that you cite, since just as soon as you cite it you're reminded of exceptions to the rule. It's the type of knowledge that helps to build judgment, patience, and prudence. No wonder so much of it feels like a parable -- professors telling stories meant to teach a lesson and to serve as a strong reminder of what *could* happen. I highly recommend the series (and thanks to Dave for pointing it out!). Link via ITunes U

Nodebox - Hyperlink Graph

Wed, 05 Dec 2007 08:23:30 -0800

I'm in love with NodeBox, a simple to use scriptable graphics tool (uses Python) for Mac OS X. Among many other things, you can use it to generate hyperlink graphs like this one (for www.seanzehnder.com).

Media Revolutions Redux

Fri, 12 Oct 2007 09:33:29 -0800

Announcing the re-birth of the Media Revolutions Project! http://www.mediarevolutions.org

Application of MapFlows Analysis - aimless wandering vs. patterned exploration

Fri, 05 Oct 2007 10:46:14 -0800

One of the applications of this technology is to provide a visual/analog means of assessing level design, with data from real players. For example, it can bring into high-relief when players are exploring a level in roughly the same manner, or if they appear to be wandering aimlessly. In both of the examples below, there was 1 fixed spawn point and roughly the same number of player-sessions of data. Each frame is 1 second of gameplay and the video plays at 12 frames per second. Example 1 - Wandering Aimlessly Example 2 - Highly-Patterned Flow Through the Level

MapFlows Videos

Thu, 04 Oct 2007 09:01:17 -0800

The MapFlows application I've been developing now has the option to generate quicktime movies of the heatmaps. These maps can either show or hide the background image of the level. For the purpose of analysis, I like to sometimes see the emergent structure of the level from the patterns of movement without having the map always in view. Below is an example of my "catwalk" map (using one of my experimental conditions) with and without the background map. Without Background Map With Background Map

MapFlows - update

Fri, 28 Sep 2007 09:48:21 -0800

I've also just completed an update of my MapFlows application, which shows a heatmap-style visualization of where players are over time in the game level. It averages all available samples within a specified "bucket" range, and then generates a color value for each pixel based on its distance from all sampled player positions. It basically treats the known (i.e. sampled) positions of players as forces on the pixel where the magnitude of the vector is inversely proportional to the straightline distance to the point.

The app saves the frame images, stats about the app performance (meaning how long it took to process), and you can also print contact sheets of the frames in order to represent the flow as a static series of images. I will post little videos of these flow-maps in the next day or so...

New App -- LogImporter

Tue, 25 Sep 2007 09:31:50 -0800

In the process of collecting data for my dissertation experiment, I amassed something like 200 sessions of game play, each about 5 minutes in duration. Each log file from these sessions had millisecond sampling of player position, camera pitch and yaw, and the player's health. This gives me millions of samples I can use to analyse my game level in a variety of ways. However, managing that much data is tricky -- especially when the software development was (is) ongoing and there are inevitably bugs in the system that require re-processing of the raw log data. In order to ensure data integrity and the ability to sort erroneous and/or invalid session logs from valid ones, I needed a dedicated utility application -- enter LogImporter. It's not the sexiest piece of software I've ever seen, but it has proven IMMENSELY helpful in verifying my data and trusting that everything that should be in the database has actually reached the database successfully. In the process of this development, I wrote a general-purpose HistogramWidget (in Java/QtJambi). The widget can take either a query string (e.g. "SELECT rowcount as valueField FROM tableFoo") or an existing TreeMap of data, and then it renders a histogram of the values in that resultset. The dark blue bar represents the bucket containing the mean, the darker purple box represents 1 standard deviation, the lighter blue represents 2 standard deviations, and the red bar indicates the currently selected log file (in the list on the left). This means that when you select an existing log file, it will show you where that falls in the distribution compared to all the other sessions in the database. This is extremely handy when you're not sure if the session you're looking at is vastly outside the norm compared to its peers. While I am currently only using it to show the rowcount for each log file, new histograms can be added extremely easily (if there's some other thing you'd like to compare across log files).

GameTracker Software Updates

Tue, 25 Sep 2007 09:22:40 -0800

I've made a bunch of updates to GameTracker in the last few weeks. 1 - Player Movement Replay -- the little green streak shows the last 100 frames of the player's position and the cone represents the player's field of view for a particular frame. 2 - Time in Cell Histogram -- you can also see a blue-ish chart in the bottom left of this image. This is a new histogram feature that shows the distribution of time spent in a particular cell. This is calculated as part of the grid analysis view, which is something I've been in the process of developing for some time (other shots of that, below). 3 - Performance of the Grid Analysis View -- The basics of this view have remained the same, but I have dramatically boosted performance by cleaning up the code and being slightly more careful about where and when the Qtjambi AbstractItemModel-based objects are initialized. The threading on this piece has also been spruced-up.

Another turn of the wheel...

Tue, 25 Sep 2007 08:57:45 -0800

While I've been rather neglectful of this, my little corner of the internet, I have a good excuse.... E and I are re-settled in Chicago-area, have almost unpacked our new home, and all-in-all life is good. I am enjoying a 1 year appointment as a Research Associate at Northwester University, which is granting me a lot of uninterrupted time to make progress on my dissertation. Things are moving along at an incredible clip... especially considering how slow it was while I was trying to do it part time for the last two years. I will be posting updates on the software and findings as I have them... Current tasks: - prepare a submission for GDC '08 - run stats on my player nav data and write up results - begin to circulate chapters of the paper to my committee - begin design and planning for a new wave of subjects in my game player behavior study

Jess Zehnder wins NAHA award!

Mon, 13 Aug 2007 09:57:37 -0800

I'm very proud of my little sister Jess for winning the Best Student Hairstylist of the Year award at the North American Hairstyling Awards (NAHA). She's quite the iconoclast: honor's student in Philosophy from Xavier University who decided to go to beauty school. Now she's tops in that arena as well. I couldn't be prouder!

Spivey and Beau at play

Wed, 08 Aug 2007 13:50:56 -0800

Dodgers v. Braves

Thu, 05 Jul 2007 13:46:44 -0800

Went to the Dodgers v. Braves game last night with some coworkers. From left to right starting on the bottom, we have Michael Paglione, Ben Hoyt, Stephen Peacock, Varun Nayak, Randy Spong, and I'm the good looking one in the Venice t-shirt. It was particularly fun because three of them have never been to a baseball game before. Two are more familiar with Cricket and I don't know what the third guy's excuse is... but it was definitely good eating and a fast-paced ballgame. Braves won 7-6.

Galway Bay

Wed, 04 Jul 2007 11:10:00 -0800

In tribute to John Romond who is getting married next weekend.... a photo I took of Galway, Ireland, where we began a trip around Europe a handful of years ago.

New Portfolio

Mon, 25 Jun 2007 00:12:58 -0800

I just updated my portfolio with a spiffy new Flex 3 / AS3 interface. Click on the picture to check it out.....

Interesting Visualization of French Political Blogosphere

Sat, 23 Jun 2007 09:30:20 -0800

I recently stumbled upon an interesting blog post at Information Aesthetics about a new visualization of the French Political Blogosphere.

Really impressive and provocative research app. A few years back I wrote a similar system as part of a research project with Jason Gallo and Eszter Hargittai at Northwestern University.

click the picture to see the demo...