Auflistung nach Autor:in "Lechner, Ulrike"
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- KonferenzbeitragActors–media–qualities: a generic model for information retrieval in virtual(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Heinrich, GregorThe article presents a model of the structural properties of virtual communities and the information they can access. It argues that a large part of the information – and actually knowledge – present in virtual communities can be identified by a graph structure that consists of three node types – actors, media and qualities – as well as the relations that connect them. Based on these relations, information retrieval and other inference mechanisms can be mapped into the model.
- KonferenzbeitragAd-hoc community composition of rescue forces in action situations(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Schau, Volkmar; Kirchner, Kathrin; Erfurth, Christian; Eichler, GeraldSecure energy and transport networks, Internet and telecommunications, are vital nerves of our highly networked society. Global mobility makes it difficult to combat and natural disasters and technological accidents can cause serious damage in a closer-knit world. In this paper we introduce the challenges in dynamic community composition of heterogeneous rescue forces (culture clash) for rescue and protection tasks and discuss our approach in the context of the "SpeedUp project" how to present a solution for ad-hoc communication, situation-aware representation, tracking and guiding in dynamic inhomogeneous communities.
- KonferenzbeitragAdaptation process for ad hoc routing protocol(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Yawut, Cholatip; Paillassa, Béatrice; Dhaou, RiadhBecause of several constraints in ad hoc networks, an adaptive ad hoc routing protocol is increasingly required. In this paper, we propose a synopsis of an adaptation process for an adaptive ad hoc routing protocol. Next, we put into practice the analysis of the process of adaptation to mobility by realizing an adaptive routing protocol: CSR (Cluster Source Routing) which is an extension of a widely used ad hoc routing protocol: DSR (Dynamic source Routing). Mobility and density metrics are considered to CSR<->DSR mode switching, it moves from a flat architecture working in DSR to a virtual hierarchical architecture. With this mode switching, CSR can enhance the scalability of the DSR routing protocol.
- KonferenzbeitragAgenten organisieren ein Intranet(Workshop Gemeinschaften in Neuen Medien (GeNeMe) 2000, 2000) Lechner, Ulrike; Klose, Martina; Schmid, Beat F.; Miler, Olga; Hengartner, Urs; Maier, Elisabeth; Richter, Lutz; Riedl, Reinhard; Kefos, ChristosZusammenfassung:'Das Papier präsentiert ein Konzept für die Modellierung von Organisationen als System von kommunizierenden Agenten, eine Referenzarchitektur für agentenbasierte Modellierung von betrieblichen Anwendungen und ein ganzheitliches Konzept für die gemeinsame Entwicklung von Organisationen und Kommunikationskanälen.
- KonferenzbeitragEine Analyse der Kommunikation in Online Support Communities – Fallbeispiel dccv.de(Workshop Gemeinschaften in Neuen Medien (GeNeMe) 2008, 2008) Dannecker, Achim; Kollmorgen, Ronald; Lechner, Ulrike
- KonferenzbeitragApplication layer scalable video coding for the iphone(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Spielvogel, Christian; Kropf, PeterVideos streamed over the Internet can be received by mobile devices anywhere and anytime. The challenges for Internet streaming include avoiding data loss and playing back the content in the desired quality. A technique for achieving these goals is Scalable Video Coding (H.264-SVC) that adapts the content to network and device characteristics without transcoding. Since there is no player for rendering scalable video content on mobile phones using more than the base layer, we present our prototype implementation that is able to decode multiple layers of scalable content in the temporal, spatial or quality domain. Currently the prototype is available and has been tested on the iPhone 3G.
- KonferenzbeitragAn approach of semantic cache for mobile devices to enhance the performance of applications(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Caetano, Marcos F.; Ribeiro Dantas, Mario AntonioWireless mobile computing has become a differential aspect to a large number of distributed applications. The main research goal related to this subject is to provide to applications a similar level of services found in structured networks. An example of interesting research topic is to improve the data replication scheme that exists in a mobile device. The use of an elaborate method can represent an improved strategy to enhance the performance and availability of applications to wireless users. In this article we present a semantic cache model study, and its implementation, as a differentiate policy for the local management of data replication. The approach assumes that an answer for a query can be satisfied totally by a local semantic segment, considering the gathering action of partial segments or helping the connection to a server and then receiving the answer. We tested the implementation of the model in a real environment, assuming three classes of queries. The first class was characterized by those queries that could be promptly answered locally. The second type of queries was answered after a local gathering operation of semantic segments. In the last situation, queries were answered after a send-receive operation to a server node in a structured network. The empirical results indicate that the approach has improved successfully the performance of the applications, avoiding unnecessary connections to a server when an answer could be reached using one local cache segment, or gathering information from the local semantic segments to compound the answer. In the case of inexistence of any local semantic segment information to reply a query, the implementation works transparently to connect to a server and then answer the wireless user.
- KonferenzbeitragAutomated robustness testing for reactive systems: application to communicating protocols(10th International Conferenceon Innovative Internet Community Systems (I2CS) – Jubilee Edition 2010 –, 2010) Khorchef, Fares Saad; Berrada, Ismail; Rollet, Antoine; Castanet, RichardIn the telecommunications field, protocols have to be seriously validated before their startup. Thus, it is necessary to test the conformance of a protocol, but it is also important to test its robustness in presence of unexpected events. This paper proposes a framework to test the robustness of a system. Firstly, we explain how to increase the nominal specification in order to take into account the hazards. Then, we show how to generate test sequences from the increased specification. Finally, we propose a case study on the SSL protocol, using the TGSE tool.
- KonferenzbeitragBenutzerfreundlichkeit und Glaubwürdigkeit von Websites mit medizinischen Inhalten(Workshop Gemeinschaften in Neuen Medien (GeNeMe) 2007, 2007) Dannecker, Achim; Lechner, Ulrike; Marz, Björn; Mönch, Matthias