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Posts Tagged ‘research’

Fritz Heckel’s Reactive Teaming

Tuesday, May 25th, 2010

Fritz Heckel, a PhD student in the Games + Learning Group at UNC Charlotte, posted a video (below) on the research he has been doing under the supervision of G. Michael Youngblood. He has been working on using subsumption architectures to create coordination among multiple game agents.

When the video first started, I was a bit confused in that he was simply explaining a FSM. However, when the first character shared a state with the second one, I was a little more interested. Still, this isn’t necessarily the highlight of the video. As more characters were added, they split the goal of looking for a single item amongst them in that they parsed the search space.

This behavior certainly could be used in games… for example, with guards searching for the player. However, this is simply solved using other architectures. Even something as simple as influence mapping could handle this. In fact, Damián Isla’s occupancy maps could be tweaked accordingly to allow for multiple agents in a very life-like way. I don’t know what Fritz is using under the hood, but I have to wonder if it isn’t more complicated.

Obviously, his searching example was only just a simple one. He wasn’t setting out to design something that allowed people to share a searching goal, per se. He was creating an architecture for cooperation. This, too, has been done in a variety of ways. Notably, Jeff Orkin’s GOAP architecture from F.E.A.R. did a lot of squad coordination that was very robust. Many sports simulations do cooperation — but that tends to be more playbook-driven. Fritz seems to be doing it on the fly without any sort of pre-conceived plan or even pre-known methods by the eventual participants.

From a game standpoint, it seems that this is an unnecessary complication.

In a way, it seems that the goal itself is somewhat viral from one agent to the next. That is, one agent in effect explains what it is that he needs the others to do and then parses it out accordingly. From a game standpoint, it seems that this is an unnecessary complication. Since most of the game agents would be built on the same codebase, they would already have the knowledge of how to do a task. At this point, it would simply be a matter of having one agent tell the other “I need this done,” so that the appropriate behavior gets switched on. And now we’re back to Orkin’s cooperative GOAP system.

On the whole, a subsumption architecture is an odd choice. Alex Champandard of AIGameDev pointed out via Twitter:

@fwph Who uses subsumption for games these days though? Did anyone use it in the past for that matter?

That’s an interesting point. I have to wonder if, as is the case at times with academic research, it is not a case of picking a tool first and then seeing if you can invent a problem to solve with it. To me, a subsumption architecture seems like it is simply the layered approach of a HFSM married with the modularity of a planner. In fact, there has been a lot of buzz in recent years about hierarchical planning anyway. What are the differences… or the similarities, for that matter?

Regardless, it is an interesting, if short, demo. If this is what he submitted to present at AIIDE this fall, I will be interested in seeing more of it.

Framsticks – Artificial LIfe Experiment

Monday, December 10th, 2007

I’m not entirely sure what to think of this project. However, it is certainly very interesting. This group is developing artificial life via what they call “Framsticks”. It is an attempt at creating artificial life forms that evolve into higher and higher functioning beings using neural networks for control and genetic algorithms for breeding more advanced, capable Framsticks. I suppose you could think of it as a less cuddly version of “Creatures“.

The sticks that comprise the body are specialized for things such as touch, smell, locomotion, ingestion, and even defense. They go into great detail on the site about how the NNs are trained and how they are applied to the Framsticks.

There are numerous (large!) videos and many pictures on the site showing some of the Framsticks in action. You can also download the software – although I admit that I haven’t done that yet. If any of you do get a chance to play around with it, I ask that you stop back by and comment on it.

Neurotic bots beats “Age of Mythology” AI

Friday, November 30th, 2007

According to a blog post on the New Scientist magazine web site, an experiment (pdf file) by some Austrian researchers shows you don’t have to be entirely sane to beat the AI in the 2002 RTS game, “Age of Mythology” by Ensemble Studios.
The group wants games to be more engaging by having emotional, not just coolly calculating, computer players. Instead of just challenging your rational planning and decision skills, you’ll have use your emotional intelligence too.

I am also very interested in the inclusion of psychology into the AI of computer games and simulations. I am very well versed in psychology and emotional response. However, I’m not entirely sure whether they proved any point here. They could claim that it was their model, which simulated “the big five” emotional dimensions to personality recognised by psychologists. On the other hand, it could very well be game design decisions or poor AI.

“Age of Mythology” was the follow up to the “Age of Empires” series. Those games were not well known for their AI prowess. (In fact, when lead designer Rick Goodman left to found Stainless Steel Studio, the bloodline was improved significantly with Empire Earth which was known for its AI. I’d love to see their neurotic bots take on that game.) Additionally, there are so many combinations of how the bot AI designed by the researchers could match up with the AI for AoM, that simply balancing those two alone would be daunting. Some very simple arbitrary choices about coefficients used in decision making could have skewed any other data one way or the other. I’m not discounting their research, but as a simulation modeller, I know the challenges involved in creating a multi-variate system such as this.

On the other hand, I think it just says more about what Ensemble did – or did not do – with the game design and AI of “Age of Mythology”.

Has Captcha been broken?

Friday, November 30th, 2007

I noticed this post at the site Coding Horror. It’s mostly a site for programmers griping about each other, but this one may be of general interest as well as something for the AI community.

If you have been on the web at all, you have probably had to type in some variant of a Captcha security code developed by the whizzes at Carnegie Mellon. (Make a comment on this post if you want to see one in action.) The whole point of it is to defeat programs that will read a security code in the actual html and enter it automatically. Also, they are designed to defeat programs that would take an image of the page (or the Captcha sequence itself) and use OCR (optical character recognition) techniques to detect what characters are being used.

The post at Coding Horror refers to an article from the Wall Street Journal about how Ticketmasteris having problems with bots and scalpers. The problem seems to be that the variant of Captcha that Ticketmaster is using is just not good enough. The solutions for theirs, and many others’, is being sold by companies. However, Captcha algorithms such as those used by Google, Hotmail and Yahoo are “unbreakable”. (Notice that no financial sites are listed?!?)
Anyway, interesting read on how humans can still defeat computers at some tasks. I suppose Alan Turing would be smirking at the attempts.

Autonomous Movement in a Hostile World

Thursday, November 15th, 2007

Movement in a dynamic world – especially with hostile entities and constantly changing safe and danger zones – is a dicey issue in game AI. AIGameDev.com has posted a great article about some work by Leslie Ikemoto from the University of Berkeley that I believe has some great future relevance to the game industry.

Although it is 153 MB, make sure you download the video file that shows the agents in motion. Great stuff!

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