Campusleben_HAW_Hamburg_41

Lehrende_HAW_Hamburg_26

Studierende_HAW_Hamburg_13

Informationen für:

Publikationen von Professorinnen und Professoren der HAW Hamburg

Jahr:  
Alle : 1982, ... , 2008, 2009, 2010, ... , 2020
Autor:  
Alle : A, À, B, C, D, E, F, G, H, I, J, K, L, M, N, O, Ö, P, Q, R, S, T, U, V, W, Y, Z 
Alle : W. Biersack, ... , Wetzel, Weyand, Weyhe, ... , Wöste 
Präferenzen: 
Referenzen pro Seite: Zeige Schlüsselwörter Zeige Zusammenfassung
Referenzen

Konferenz, Symposium, Vortragsreihe, Einzelausstellung, Modenschau, Künstl. Leitung (als Ausrichter):

default
Matthias Wählisch, Thomas C. Schmidt und Georg Wittenburg
A Common API for Hybrid Group Communication
Mohamed Younis und Chun Tung Chou (Hrsg.) Proc. of the 34th IEEE Conference on Local Computer Networks (LCN) , Seite 265--268.
Verlag: IEEE Press, Piscataway, NJ, USA

Marker: TI-I

default
Matthias Wählisch, Thomas C. Schmidt und Georg Wittenburg
BIDIR-SAM: Large-Scale Content Distribution in Structured Overlay Networks
Mohamed Younis und Chun Tung Chou (Hrsg.) Proc. of the 34th IEEE Conference on Local Computer Networks (LCN) , Seite 372--375.
Verlag: IEEE Press, Piscataway, NJ, USA

Marker: TI-I

Zusammenfassung: IPTV, software replication and other large-scale distribution tasks urge the need for efficient multicast mechanisms in overlay networks. Current multicast solutions on the application layer are either efficient, structured, but inflexible, or flexible, unstructured, but of lesser efficiency. This paper introduces Scalable Adaptive Multicast on BI-DIRectional shared trees, a new structured but flexible approach to content distribution. BIDIR-SAM is the first DHT-based overlay multicast that distributes any source multicast data according to source-specific shortest path trees. Built upon bi-directional shared prefix trees, the approach distributes packets uniquely via fully redundant paths, and allows for highly flexible network adaptivity. Guided by an overlay abstraction, it operates directly on top of a prefix routing and does not rely on any kind of rendezvous point or bootstrapping.

default
Alexander Knauf, Thomas C. Schmidt und Matthias Wählisch
Scalable Distributed Conference Control in Heterogeneous Peer-to-Peer Scenarios with SIP
Mobimedia '09: Proc. of the 5th International ICST Mobile Multimedia Communications Conference aus ACM Digital Library , Seite 1--5.
Verlag: ICST, Brussels, Belgium

Marker: TI-I

Zusammenfassung: An increasing number of popular conferencing applications operate in a lightweight, infrastructure-independent ad hoc fashion and extend into the mobile realm. These P2P-type systems raise the demand for scalable, adaptive self organization of conferencing in a standard-compliant way. This paper addresses the challenge of distributed conference management with SIP and makes the following two contributions. First, we define distributed operations of a conference focus by splitting the role of identifier and locator of the conference URI. Second, we extend the SIP conference event package by states that ensure a uniformly consistent view at the conference and facilitate resource-adaptive self organization.

default
Matthias Wählisch, Thomas C. Schmidt und Georg Wittenburg
OASIS: An Overlay Abstraction for Re-Architecting Large Scale Internet Group Services
Andreas Mauthe, Sherali Zeadally, Eduardo Cerqueira und Marília Curado (Hrsg.) Future Multimedia Networking. 2nd International Workshop, FMN 2009, Proceedings Band 5630 aus Lecture Notes in Computer Science , Seite 95--106.
Verlag: Springer-Verlag, Berlin Heidelberg

Marker: TI-I

Zusammenfassung: There is an increasing economic desire driven by widespread applications like IPTV or conferencing that a next generation Internet will grant transparent group communication service to all its stationary and mobile users. In this paper, we present a generic approach to inter-domain multicast, which is guided by an abstract, DHT-inspired overlay, but may operate on a future Internet architecture. It is based on the assumptions of a globally available end-to-end unicast routing between resolvable locators, taken from a name space that allows for aggregation. Our protocol design accounts for this aggregation, leading to forward path forwarding along bidirectional shared distribution trees in prefix space. The scheme facilitates multipath multicast transport, offers fault-tolerant routing, arbitrary redundancy for packets and paths and remains mobility agnostic. We present its applicability to IPv6, and evaluate signaling costs analytically based on its k-ary tree structure.

default
Hans L. Cycon, Gabriel Hege, Detlev Marpe, Mark Palkow, Thomas C. Schmidt und Matthias Wählisch
{Connecting the Worlds: Multipoint Videoconferencing Integrating H.323 and IPv4, SIP and IPv6} with Autonomous Sender Authentication
ISCE2009 --- 13th International Symposium on Consumer Electronics , Seite 890--893.
Verlag: IEEE Press, Piscataway, NJ, USA

Marker: TI-I

Zusammenfassung: In this paper we present a multipoint media conference software with extended network capabilities. Its core components combine an advanced, highly efficient H.264/AVC video coding system. Session signaling follows the SIP standard and simultaneously supports IPv4 and IPv6. Built upon an underlying peer-to-peer communication scheme, it further supports advanced integration with legacy MCUs and thereby enables hybrid sessions that extend into the H.323 world. We demonstrate how our software can span fully functional conferences across these worlds by deploying a passive gateway peer. Finally, we address security issues arising in distributed conferencing systems. It is shown, how the use of cryptographically generated identifiers enables the application to authenticate data on a packet level, thereby preventing abuse and impersonation of the conference overlay network.

default
Matthias Wählisch, Thomas C. Schmidt und Georg Wittenburg
A Generalized Group Communication Network Stack and its Application to Hybrid Multicast
Proceedings of the 28th IEEE INFOCOM. Student Workshop
Verlag: IEEE Press, Piscataway, NJ, USA

Marker: TI-I

Zusammenfassung: Group communication services are most efficiently implemented on the lowest layer available. Network layer multicast transparently delegates group distribution to the link layer wherever possible. Native multicast deployment, though, has been mainly limited to 'walled gardens' within provider domains. Overlay multicast overcomes these deployment restrictions on the price of a performance penalty. Current activities focus on hybrid approaches which dynamically combine multicast in overlay and underlay, and adaptively optimize group communication. The basic requirement for such a flexibly deployable architecture is a layer-transparent group communication stack that integrates variable multicast protocols by a common API. In this paper, we present a common group communication stack which serves the requirements of data distribution and maintenance for multicast and broadcast on a middleware abstraction layer, suitable for underlay and overlay communication. We discuss its application in the context of hybrid multicast schemes.

default
Matthias Wählisch, Thomas C. Schmidt und Gabriel Hege
Overlay AuthoCast: Distributed Sender Authentication in Overlay Multicast
Proceedings of the 28th IEEE INFOCOM. Student Workshop
Verlag: IEEE Press, Piscataway, NJ, USA

Marker: TI-I

Zusammenfassung: Multicast services raise significant operational and security challenges not only when deployed on the Internet layer, but also in overlay networks. Large P2P groups as emerging from IPTV applications may be abused by unwanted traffic or denial of service attacks through amplified flooding. In this paper, we introduce a distributed, autonomously verifiable scheme for multicast sender authentication, which does not depend on pre-established trust relationships. Based on cryptographic identifiers and passport packets, any overlay peer is enabled to verify the origin of data prior to forwarding and to repel its misuse. Dynamic ingress filtering and individually established gradual trust allow for a lightweight protection of the distribution system in structured overlays.

default
Gabriel Hege, Thomas C. Schmidt, Matthias Wählisch, Hans L. Cycon und Mark Palkow
``Als die Filme laufen lernten" --- Session Mobility for Videoconferencing on Mobiles
Andrew Cormack und others (Hrsg.) Proceedings of the TERENA Networking Conference (TNC 2009)
Verlag: TERENA, Amsterdam,

Marker: TI-I

Zusammenfassung: In recent years, video conferencing solutions have started to become available as an end-to-end service on personal devices, and are now on the spot to enter the class of mobile smartphones. In this paper we report on advanced mobility services of our video conferencing software. Based on emerging standards in SIP signaling and scalable H.264 video compression, the solution supports for a seamless integration of mobile smartphones into group conferences, and in particular extends group conference management to comply with session mobility. While remaining on a conference call, a user is thus enabled to shift his presence from a stationary end system to a mobile, and continue the conversation while leaving the office.

default
Matthias Wählisch, Thomas C. Schmidt und Georg Wittenburg
Broadcasting in Prefix Space: P2P Data Dissemination with Predictable Performance
Mark Perry, Hideyasu Sasaki, Matthias Ehmann, Guadalupe Oritz Bellot und Oana Dini (Hrsg.) Proceedings of the Fourth International Conference on Internet and Web Applications and Services (ICIW'09) , Seite 74--83.
Verlag: IEEE Computer Society Press, Los Alamitos, CA, USA

Marker: TI-I

Zusammenfassung: A broadcast mode may augment peer-to-peer overlay networks with an efficient, scalable data replication function, but may also give rise to a virtual link layer in VPN-type solutions. This paper introduces a simple broadcasting mechanism in prefix space of distributed hash tables and concentrates on the analysis of this prefix flooding scheme. Starting from simple models of recursive k-ary trees, we analytically derive distributions of hop counts and the replication load. Extensive simulation results are presented further on, based on an implementation within the OverSim framework. Comparisons are drawn to Scribe, taken as a general reference model for group communication according to the shared, rendezvous-point-centered distribution paradigm. The prefix flooding scheme thereby confirmed its widely predictable performance and consistently outperformed Scribe in all metrics. Reverse path selection in overlays is identified as a major cause of performance degradation.

Buchbeiträge:

default
Th. Willner
Direct Liquefaction as a Future Basis for 3rd Generation Biofuel Production
Proceedings of the 17th European Biomass Conference & Exhibition- Tagungsband
Seite 1963-1966.
Juli 2009

Marker: LS-VT

Seite:  
Zurück | 1, 2, 3, 4, 5, 6, 7 | Weiter
Total:
1021
Export als:
BibTeX, XML

Letzte Änderung: 23.01.15

An die Redaktion