How It Works: Bitcoin Edition

Nothing like avoiding end-of-the-year physical cleanup with end-of-the-year virtual cleanup! I finally got around to reading this detailed description of how Bitcoin works, recommended by Schneier on his weblog, and I need to hang on to this for next time I’m teaching security. From a teaching perspective, it does a nice job of showing how all of the various types of cryptography come together in an interesting way in this protocol. This is the part that always seems sort of wild to me: The idea is to make it so everyone (collectively) is the bank. In particular, we’ll assume that … Continue reading How It Works: Bitcoin Edition

Stabby Robot Less Stabby

First, and most important obviously, this is pretty neat research into training robot motion with online, and non-optimal, feedback. It’s a nice consideration of the type of feedback one is likely to get, or to get easily. And the illustrative video on their page is pretty great (I found the moment when they showed the robot how to point the knife towards itself, not someone else, adorable…) But it’s also worth noting that the TechCrunch story on the research is pretty hysterical: “Cornell Researchers Help Robot Unlearn Stabby Motions With A Human Trainer”.

Building the right community for community editing

There’s something unavoidable about Wikipedia, even when you acknowledge its flaws, which makes it a constantly interested phenomenon to investigate and analyze. As the article notes, its rankings in search results and use in question answering systems like Siri only make it more interesting to understand what’s going on with it. Looking at the effect of the editorial structure and automated tools for handling edits is particularly interesting; I hadn’t really thought about the effect of bots on participation in this way: In their paper on those findings, the researchers suggest updating Wikipedia’s motto, “The encyclopedia that anyone can edit.” … Continue reading Building the right community for community editing

Watch where you put that phone

This is awesome – I’ve long been in love with intrusions that rely on listening in on the sound of keystrokes, or the wiggle of a laptop screen, or what have you to learn and then reproduce what has been typed. This variation where a smartphone on your desk can pick up typing vibrations and from there learn to recognize what you are typing. It’s proof of concept, not found out in the wild at this point, but still very cool.

Traveling Happy Truck Drivers

Starting out as an explanation of the traveling salesman problem, this article goes on to also be an excellent, and I think understandable, explanation of what an algorithm is and computational complexity. If you want to get a quick sense of what computer science is concerned about that goes beyond just “how to program”, and is more the “how to solve problems” side of things, this is a good read. In 2006, for example, an optimal tour was produced by a team led by Cook for a 85,900-city tour. It did not, of course, given the computing constraints mentioned above, … Continue reading Traveling Happy Truck Drivers

Of course they put E.T. in New Mexico

The news that the landfill of Atari’s E.T. games is going to be excavated swept through the internet. This makes me doubly excited that I still have my copy and I’m considering using it an an anchor point for a “play bad games” day in my intro game design course in the fall. Particularly having also found this really cool review of the games flaws and fixes for them. It starts from the position that the game is actually fairly good, and even groundbreaking, except for a few flaws or misunderstandings about the game (such as, that it is an … Continue reading Of course they put E.T. in New Mexico

Data Vis Roundup

I’m supervising a capstone project right now where students are providing data analysis and visualization support for a local organization, and the following set of links have been queueing up in my feed as to-read items for me related to that project (and, hopefully, to-read items for them): eagereyes has a nice summary of ISOTYPE (International System of Typographic Picture Education) which in the roughest strokes is those charts where the number of an item is represented not by a bar but as a collection of images or icons representing the thing being counted. But it’s a lot more complicated … Continue reading Data Vis Roundup


I’m helping organize a panel of faculty at my school who have been using a range of different technologies to support student interaction in and out of class. With so many options out there, we want to focus on what has worked for us, what hasn’t worked, and start some conversations around how to make the jump from looking at your course, with its content, outcomes, and pedagogy, and draw on others experience with these tools on the ground with our systems and our students to have some idea what options might be appropriate. Independently of this, I’ve got a … Continue reading Discourses

Sometimes you can blame the compiler. Sort of.

I don’t know if this weblog entry about bug hunting in large scale game development is more appropriate for my spring games course or my spring project management course. The stories are great for both directions. Team members with poorly defined roles! Frantic timelines leading to bugs! The reality of entire days lost to a bug that won’t be found, let alone fixed! Bugs explained in simple code a novice student can understand! I particularly enjoyed the explanation of why the live server compiler ran without debug capabilities, violating the ideal that the dev and live servers are identically configured, … Continue reading Sometimes you can blame the compiler. Sort of.

Risks in user content

My security class is talking about the types of commonly seen mistakes that can crop up when writing programs that lead to security flaws, and while I usually introduce the ideas using “normal” programming examples because it is the common background I can assume my students have, I’m trying to help the students map these ideas to what they’ve seen of database or web development as well. So I finally went back in my saved links and read through a Google blog post from a month ago about security issues in hosting user content, specifically web content. After a brief … Continue reading Risks in user content