Learn More
Online auctions are vulnerable to shill bidders, who intend to artificially raise bidding prices, causing winning bidders to pay more than they should pay for auctioned items. Detection of such fraudulent behaviors is very difficult, especially when an auction is in progress, or " live ". This paper focuses on a formal technique to detect shilling behaviors(More)
Agents are becoming one of the most important topics in distributed and autonomous decentralized systems, and there are increasing attempts to use agent technologies to develop large-scale commercial and industrial software systems. The complexity of such systems suggests a pressing need for system modeling techniques to support reliable, maintainable and(More)
The number of Internet auction shoppers is rapidly growing. However, online auction customers may suffer from auction fraud, sometimes without even noticing it. In-auction fraud differs from pre-and post-auction fraud in that it happens in the bidding period of an active auction. Since the in-auction fraud strategies are subtle and complex, it makes the(More)
UML, being the industry standard as a common OO modeling language, needs a well-defined semantic base for its notation. Formalization of the graphical notation enables automated processing and analysis tasks. This paper describes a methodology for synthesis of a Petri net model from UML diagrams. The approach is based on deriving Object Net Models from UML(More)
UML statecharts are widely used to specify the dynamic behaviours of systems. To support systematic simulation of such models, we propose an approach to map systems specified using UML diagrams to colored Petri net notations. Simulation results are provided in form of self-defined trace files and Message Sequence Charts. A prototype tool is described. One(More)
UML statecharts are used for describing dynamic aspects of system behavior. The work presented here extends a general Petri net-based methodology to support formal modeling of UML statecharts. The approach focuses on the specific task of generating explicit transition models associated with the hierarchical structure of statechart. We introduce a(More)
We present a shilling behavior detection and verification approach for online auction systems. Assuming a model checking technique to detect shill suspects in real-time, we focus on how to verify shill suspects using Dempster-Shafer theory of evidence. To demonstrate the feasibility of our approach, we provide a case study using real eBay auction data. The(More)