Tracy Mullen presented work on market-based negotiations for digital library services. This work is based on two assumptions: 1) available resources are limited, and 2) what people may want to do in a digital library is unpredictable. Given these assumptions, digital libraries should provide a flexible, open and extensible infrastructure that supports different market practices.
The University of Michigan Digital Library (UMDL) project is designing and implementing a digital library based on a system of software agents that interact with each other and with end users. Software agents are used to perform various activities needed to deliver goods and services. Because there are multiple competing agents trying to accomplish multiple tasks as efficiently and as cheaply as possible at a given time, resource competition needs to be resolved. UMDL sets the agents to negotiate with each other, so that globally optimal agreements can be reached. Instead of hardwiring pre-defined negotiations, UMDL uses user-definable auctions that can be dynamically established when goods or services are to be sold or bought. Auction mechanisms need a number of parameters to be fully specified. These parameters include the type of goods, price quote policy, price quote interval, clearing policy, and tie breaking, among other things.
UMDL's digital library is a market place with dynamically evolving configurations that include goods that are being sold and the mechanisms by which they are negotiated and exchanged. When given buyers' demand profiles and the current resource congestion profile, the system will decide on a level of service for each buyer. Currently, there is an auction server working.
During the question period, someone asked about the danger of shill-bots. Tracy answered that it is possible to use certificates of ``honesty'' to decide who is allowed to transact in the system. Christian Frank wondered about the scarcity of information goods. Tracy pointed out that one should look at other resources as well. Users' time and the system's computational resources can both be scarce. Someone asked about protections that the system offers against unexpectedly high demands. Does UMDL prevent crashes from happening in such scenarios? Tracy answered that the marketplace is self-regulating. As the demand increases, the price of the goods or service also increases, which can drive the demand down. But UMDL can also resort to distributed auctions. The last comment came from Doug Tygar: ``The notion of having auction markets for information goods is terrific, because that means that we may have a futures market and I can short my colleagues' papers!''