Stefan Penz

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A user is only anonymous within a set of other users. Hence, the core functionality of an anonymity providing technique is to establish an anonymity set. In open environments, such as the Internet, the established anonymity sets in the whole are observable and change with every anonymous communication. We use this fact of changing anonymity sets and present(More)
The goal of anonymity providing techniques is to preserve the privacy of users, who has communicated with whom, for how long, and from which location, by hiding traffic information. This is accomplished by organizing additional traffic to conceal particular communication relationships and by embedding the sender and receiver of a message in their respective(More)
The development of applications and protocols for future wireless communication systems requires powerful tools for testing and optimization in mobile ad-hoc networks. This especially holds true for applications that are based on relatively unreliable wireless multicast communication. In this paper we propose an extension to the ns-2 network simulator that(More)
The efficient assessment of connection stability in pervasive wireless environments is a crucial yet insufficiently explored problem. Existing stability assessment approaches for mobile networks focus rather on link stability and are based on unrealistic assumptions. In this paper, we propose an extension for the prevalent DSR routing protocol that allows(More)
Wireless ad-hoc networks are commonly supposed to be a key technology for future ubiquitous computing environments. The dynamic nature of such networks demands mechanisms that allow the users to assess the availability of given network connections. In this paper we present a novel connection stability heuristic based on neighborhood information of(More)
Service management in mobile ad-hoc networks has been a hot research topic in the past few years. With this demonstrator, we present the first service-oriented middleware that unifies semantic service description, service query management and Peer-to-Peer-based query dissemination. By adding a comfortable graphical interface on top of our middleware, we(More)
Mobile ad-hoc networks differ from fixed networks in two essential points: On one hand, the spontaneous formation of these networks by mobile devices requires a dynamic service management system that allows the users to discover and access services offered by other devices on-demand. On the other, multi-hop wireless communication leads to limited and(More)
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