Ralf Steinmetz

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We describe the i-LAND environment which constitutes an exampleof our vision of the workspaces of the future, in this casesupporting cooperative work of dynamic teams with changing needs.i-LAND requires and provides new forms of human-computerinteraction and new forms of computer-supported cooperative work.Its design is based on an integration of(More)
We present the ConnecTable, a new mobile, networked and context-aware information appliance that provides affordances for pen-based individual and cooperative work as well as for the seamless transition between the two. In order to dynamically enlarge an interaction area for the purpose of shared use, a flexible coupling of displays has been realized that(More)
This paper discusses the quality of service (QoS)-aware composition of Web services. The work is based on the assumption that for each task in a workflow a set of alternative Web services with similar functionality is available and that these Web services have different QoS parameters and costs. This leads to the general optimization problem of how to(More)
This paper presents a new approach to generate biometric hash values based on statistical features in online signature signals. Whilst the output of typical online signature verification systems are threshold-based true-false decisions, based on a comparison between test sample signals and sets of reference signals, our system responds to a signature input(More)
Layer encoded video is an elegant way to allow adaptive transmissions in the face of varying network conditions as well as it supports heterogeneity in networks and clients. As a drawback quality degradation can occur, caused by variations in the amount of transmitted layers. Recent work on reducing these variations makes assumptions about the perceived(More)
In the application domain of electronic commerce, biometric authentication can provide one possible solution for the key management problem. Besides server-based approaches, methods of deriving digital keys directly from biometric measures appear to be advantageous. In this paper, we analyze one of our recently published specific algorithms of this category(More)
The development of new multimedia services and environments requires new concepts both to support the new working process and to protect the multimedia data during the production and distribution. This article addresses imagehideo authentication and copyright protection as major security demands in digital marketplaces. First we present a content-based(More)