Supply Chains, Terrorists Attacks, and Agent-Based Modeling

I have recently been doing some work on supply chains and, more generally, agent-based modeling in general. There is a certain art to making an agent-based model that is complex enough to capture the problem you are trying to model but still simple enough to remain manageable. Languages like NetLogo are excellent in that they eliminate nearly all extraneous code and one is left with something that almost (OK, maybe I'm being generous) looks like pseudo-code. Nearly all the code relates directly to the problem.

Still, its lots of fun.

On that note, I have posted a NetLogo model on supply chain survivability. The model itself is interesting in that I had to implement Dijistra's to calculate the minimal path between every pair of nodes. This was needed to later calculate the graph's clustering coefficient and the characteristic path length—two measures of a graph's connectivity, the smaller they are the closer everyone is to everyone else (thus, the shorter it takes to get items to the customers). Also note that the model generates small-world graphs (using preferential attachment) as well as random graphs. This model is the basis of some work we are doing. Anyone out there interested in this kind of stuff, let me know.

Three New Papers for AAMAS

We had three papers accepted to this year's Autonomous Agents and Multiagent Systems Conference. The first one will get a full presentation and the other two will be presented as posters.

• Benito Mendoza and José M. Vidal. Bidding Algorithms for a Distributed Combinatorial Auction. In Proceedings of the Autonomous Agents and Multi-Agent Systems Conference, 2007.

  Benito builds on my previous effort to design a bidding algorithm for the PAUSE auction by providing a much faster bidding algorithm. The PAUSE auction is a combinatorial auction in which the bidders themselves solve the winner determination problem in order to win. They do so because that is the only way to win! Thus, the auction provides a simple way to distribute the computation among the agents. Our algorithms implement the myopically-optimal strategy for the agents in such an auction which is to calculate a new winning bidsest but only if in that bidset they would get more utility than they get from the currently winning bidset. In other words, if I don't get any more utility from a new bidset then I won't bother to calculate one (of course, some else might think differently.

• Hrishikesh J. Goradia and José M. Vidal. An Equal Excess Negotiation Algorithm for Coalition Formation. In Proceedings of the Autonomous Agents and Multi-Agent Systems Conference, 2007.
  

  Hrishikesh's attacks a problem similar to the one solved by the PAUSE auction but in this case it is the goods (items for sale) which negotiate to find the best allocation. This maps better to service-oriented architecture scenarios where various service providers are trying to sell their services but the buyers only want bundles. For example, you might only want a shipping service if you can also buy the book you want, both for less than $10. We present an algorithm based on Equal Excess theory which is an old solution concept to the negotiation problem (aka characteristic form game).

• Hong Jiang, José M. Vidal, and Michael N. Huhns. EBDI: An Architecture for Emotional Agents. In Proceedings of the Autonomous Agents and Multi-Agent Systems Conference, 2007.

  Hong is studying the problem of how to incorporate established emotional models from psychology into autonomous agents, namely BDI agents. This paper presents a first try at an architecture that will blend these two. The goal is to develop agents that behave like humans—with all the irrationality that that implies. We speculate that as agents start to take over more of our tasks, such as buying/bargaining with others, that users will be angry if their agents do not behave like they would, even if such a behaviors would be deemed irrational by a standard utility-maximizing model.

New NetLogo Models

This semester's multiagent systems' class, while small, has led to the development of a lot of interesting and fun NetLogo models. I have posted a few of them in my MAS Netlogo page. The Sodoku puzzle using distributed breakout is especially fun.

B2B Workflows and Characteristc Form Games

Hrishi will be presenting a paper this weekend on his work on workflow automation using multiagent systems. The paper is:

• Hrishikesh Goradia. Towards B2B Automation Via Coalition Formation Among Service Agents. In Proceedings of the IBM PhD Symposium at the Fourth International Conference on Service Oriented Computing, p. 43--48, 2006.

Research Summary Slides

I have posted a copy of my slides for this Friday's Seven Minute Madness (2:30pm in 300 Main Street, B213). They provide a pithy summary of what we are doing now.

Research Opportunities for Undergraduates or Graduates

I have a couple of programming projects which are a great way to get started learning about multiagent systems and would look great in your resume. Note that these are not paid positions, but you could get credit for them as a directed study if you want. Graduate students might also be interested as a way to get a flavor of what we do.

1. I am writing a multiagent systems' textbook which includes a lot of sample programs written in NetLogo. I already have a some programs but I need a bunch more. If you are interested in writing some, let me know. NetLogo is easy to learn and tons of fun to use. It is an agent-based modeling language that can be used in a surprinsingly large set of domain areas such as physics, economics, sociology, chemistry, biology, and many others.
2. I am interested in developing an Ajax social bookmarking application for academic publications, like citeulike but with support for ontologies and automated recommendations.
3. I am also interested in developing an Ajax system for distributed combinatorial auctions using some of the algorithms we have developed--available from my list of publications.

Pausebid Poster

I have finished my pausebid poster for the workshop. I found out that it is not easy to explain how an algorithm works on a poster! It seems there is no substitute for staring and thinking about it, drawing all kinds of pictures to get a feel for how it works. Also, in related news, Benito is already working on a faster version of the algorithm which is coming along really well.

Summer 2006 Papers: AAAI

Hong and I managed to get papers admitted to AAAI workshops. We will be presenting them at the conference in Boston. They are

• Hong Jiang and José M. Vidal. From Rational to Emotional Agents. In Proceedings of the AAAI Workshop on Cognitive Modeling and Agent-based Social Simulation, 2006.
• José M. Vidal. Multiagent Coordination Using a Distributed Combinatorial Auction. In AAAI Workshop on Auction Mechanism for Robot Coordination, July; 2006.

Spring 2006 Papers

We have a revised version of Murali's paper, who we are sorry to say left us for a high-paying job at Microsoft, and a new paper on emotional agents.

• Muralidhar V. Narumanchi and José M. Vidal. Algorithms for Distributed Winner Determination In Combinatorial Auctions. In LNAI volume of AMEC/TADA, Springer. 2006
• Hong Jiang, José M. Vidal, and Michael N. Huhns. Incorporating Emotions into Automated Negotiation. In Proceedings of the Agent Construction and Emotions Workshop, 2006

Also, we have new models in our MAS NetLogo models page and our MAS Reading Group has been very busy this Spring, drop by if you are interested.