This issue of SIGecom Exchanges includes five papers.

The first paper in this issue is entitled "Developing Adaptive Auction Mechanisms." While mechanism design has traditionally been an analytic process requiring rationality assumptions about bidders, these assumptions often do not hold in practice. In this paper, an approach to creating mechanisms that adapt to empirical bidder behavior in response to auction results is presented, along with an illustrative example of its implementation.

The second paper is entitled "Allocating Indivisible Goods." The problem of allocating divisible goods has enjoyed a lot of attention in both mathematics (e.g. the cake-cutting problem) and economics (e.g. market equilibria). On the other hand, the natural requirement of indivisible goods has been somewhat neglected. In this work the authors study a fairness criterion for allocating indivisible goods.

In the third paper, entitled "Detection Tests for Identifying Violators of Multi-party Contracts," the authors investigate how to model contracts involving multilateral relations and at the same time facilitate the identification of parties responsible for contract violations. They provide algorithms for detecting violations and identifying violators.

The fourth paper is entitled "Certifying Authenticity via Fiber-Infused Paper." A certificate of authenticity (COA) is an inexpensive physical object that has a random and unique structure with a high cost of near-exact reproduction. This positioning article introduces a novel scanner for fiber-based COAs and overviews the key related challenges and applications for this relatively novel technology.

In the final paper, "A Server-mediated Peer-to-peer System," the authors propose a server-mediated peer-to-peer system to address common problems in peer-to-peer networks, including (1) limited search scope, (2) dynamic nature of peers, and (3) lack of collaboration among peers. Two proposed features, assisted-search and assisted-download, significantly improve the performance of searching and downloading.

The final paper is a preview of what is to come in our next issue, a special issue on the economics of peer-to-peer systems.

Enjoy,