König, André ; Ackermann, Ralf ; Hollick, Matthias ; Steinmetz, Ralf (2006)
Geographically secure routing for mobile ad hoc networks : a cross-layer based approach.
Conference or Workshop Item

Ackermann, Ralf ; Dittler, Hans Peter (2006)
IP-Telefonie mit Asterisk : Aufbau von Nebenstellenanlagen für VoIP auf Linux-Basis - inklusive SIP.
Book

Schmitt, Johannes ; Ackermann, Ralf ; Görtz, Manuel ; Steinmetz, Ralf (2006)
VoIP-Sicherheit Status Quo und neue Aspekte.
Conference or Workshop Item

Steinmetz, Ralf ; Ackermann, Ralf
ed.: Bruns, Kai (2005)
Medien in Digitalen Netzwerken.
In: Taschenbuch der Medieninformatik : mit 39 Tabellen, Edition: 1. Auflage
Book Section

Meyer, Lutz ; Leibold, H. ; Mai, R. ; Ackermann, Ralf ; Schebek, Liselotte (2004)
Analysis of the exergetic performance of a novel hot gas cleaning facility.
In: World Biomass Conference <2, 2004, Roma>: Biomass for Energy, Industry and Climate Protection ; proceedings of the conference held in Rome, Italy 10 - 14 May 2004 / [Jointly organised by: Energia TA; WIP Munich]. Ed. by W.P.M Van Swaaij...- Florence : ETA
Book Section

Goertz, Manuel ; Ackermann, Ralf ; Schmitt, Johannes ; Steinmetz, Ralf (2004)
Context-aware communication services : a framework for building enhanced IP telephony services.
Conference or Workshop Item

Goertz, Manuel ; Ackermann, Ralf ; Steinmetz, Ralf (2004)
Enhanced SIP communication services by context sharing.
Conference or Workshop Item

Gasafi, Edgar ; Ackermann, Ralf ; Schebek, Liselotte (2004)
Identification of dominant process steps of supercritical water gasification systems for bio-based feedstocks.
In: World Biomass Conference <2, 2004, Roma>: Biomass for Energy, Industry and Climate Protection ; proceedings of the conference held in Rome, Italy 10 - 14 May 2004 / [Jointly organised by: Energia TA; WIP Munich]. Ed. by W.P.M Van Swaaij...- Florence : ETA
Book Section

Schebek, Liselotte ; Düpmeier, C. ; Ackermann, Ralf (2004)
Kompetenznetzwerk "Methoden in der Verfahrensentwicklung".
Conference or Workshop Item

Martinovic, Ivan ; Goertz, Manuel ; Ackermann, Ralf ; Mauthe, Andreas ; Steinmetz, Ralf (2004)
Trust and context : two complementary concepts for creating spontaneous collaborative networks and intelligent applications.
Conference or Workshop Item

Goertz, Manuel ; Ackermann, Ralf ; Steinmetz, Ralf (2004)
The digital call assistant : determine optimal time slots for calls.
Conference or Workshop Item

Ackermann, Ralf (2003)
Gateways and Components for Supplementary IP Telephony Services in Heterogeneous Environments.
TU Darmstadt
Ph.D. Thesis, Primary publication

Brucherseifer, Eva ; Ackermann, Ralf (2003)
Design am Arbeitsplatz : den UNIX-Desktop KDE besser nutzen.
In: c't
Article

Ackermann, Ralf (2003)
Gateways and components for supplementary IP telephony services in heterogeneous environments.
TU Darmstadt
Ph.D. Thesis

Görtz, Manuel ; Ackermann, Ralf ; Mauthe, Andreas ; Steinmetz, Ralf (2003)
Using context informations to avoid service interactions in IP telephony.
Conference or Workshop Item

Dittmann, Jana ; Steinebach, Martin ; Wohlmacher, Petra ; Ackermann, Ralf (2002)
Digital watermarks enabling e-commerce strategies : conditional and user specific access to services and resources.
In: EURASIP journal on applied signal processing
Article

Steinmetz, Ralf ; Ackermann, Ralf ; Roedig, Utz ; Goertz, Manuel ; Schumacher, Markus (2002)
IP-Telefonie : Protokolle, Herausforderungen, Lösungen und kritische Analyse der Sicherheit.
In: Arbeitsgemeinschaft des VDE Rhein-Main: Presentation series ; [IP-Plattform für moderne Kommunikation 14.1.-4.2.2002, Frankfurt a. M.]- Frankfurt a.M., 2002.- S. 57-77
Article

Steinebach, Martin ; Siebenhaar, Frank ; Neubauer, Christian ; Ackermann, Ralf ; Roedig, Utz ; Dittmann, Jana (2002)
Intrusion detection systems for IP telephony networks.
Conference or Workshop Item

Görtz, Manuel ; Ackermann, Ralf ; Karsten, Martin ; Steinmetz, Ralf (2002)
Using a multi-layer approach to tackle the service interaction problem in telephony scenarios.
Conference or Workshop Item

Dittmann, Jana ; Wohlmacher, Petra ; Ackermann, Ralf ; Wohlmacher, P. (2001)
Conditional and user specific access to services and resources using annotation watermarks.
Conference or Workshop Item

Roedig, Utz ; Ackermann, Ralf ; Steinmetz, Ralf (2001)
IP-Telefonie und Firewalls, Probleme und Lösungen.
In: Praxis in der Informationsverarbeitung und Kommunikation (PIK), 24
Article

Ackermann, Ralf ; Görtz, M. ; Karsten, M. ; Steinmetz, Ralf (2001)
Prototyping a PDA based communication appliance.
Conference or Workshop Item

Ackermann, Ralf ; Schumacher, M. ; Roedig, U. ; Steinmetz, Ralf (2001)
Vulnerabilities and security limitations of current IP telephony systems.
Conference or Workshop Item

Ackermann, Ralf ; Darlagiannis, V. ; Görtz, M. ; Karsten, M. ; Steinmetz, Ralf (2001)
An open source H.323-SIP gateway as basis for supplementary service interworking.
Conference or Workshop Item

Ackermann, Ralf ; Roedig, U. ; Zink, M. ; Griwodz, C. ; Steinmetz, Ralf (2000)
Associating network flows with user and application information.
Conference or Workshop Item

Ackermann, Ralf ; Roedig, U. ; Steinmetz, Ralf (2000)
Entwicklung und Nutzung von IP-Telefonie Anwendungen auf Unix-Systemen.
In: GUUG-Nachrichten
Article

Roedig, Utz ; Ackermann, Ralf ; Steinmetz, Ralf (2000)
Evaluating and improving firewalls for IP-telephony environments.
Conference or Workshop Item

Ackermann, Ralf (2000)
Firewalls and their impact on multimedia systems.
Conference or Workshop Item

Ackermann, Ralf ; Rensing, C. ; Noll-Hussong, S. ; Wolf, L. ; Steinmetz, Ralf (2000)
SSS4it - secure session setup für Internet-Telefonie.
Conference or Workshop Item

Darlagiannis, Vasilios ; Ackermann, Ralf ; El-Saddik, A. ; Georganas, N. ; Steinmetz, Ralf (2000)
Suitability of Java for virtual collaboration.
Conference or Workshop Item

Schumacher, Markus ; Ackermann, Ralf ; Steinmetz, Ralf (2000)
Towards security at all stages of a system's life cycle.
Conference or Workshop Item

Ackermann, Ralf ; Darlagiannis, V. ; Steinmetz, Ralf (2000)
Using DMIF for abstracting from IP-telephony signaling protocols.
Conference or Workshop Item

Roedig, Utz ; Ackermann, Ralf ; Tresse, M. ; Wolf, L. ; Steinmetz, Ralf (2000)
Verbesserte Systemsicherheit durch Kombination von IDS und Firewall.
Conference or Workshop Item

Ackermann, Ralf ; Pommitz, J. ; Wolf, L. C. ; Steinmetz, Ralf (1999)
Eine virtuelle PBX.
Conference or Workshop Item

Ackermann, Ralf ; Pommitz, J. ; Wolf, L. C. ; Steinmetz, Ralf (1999)
MBone2Tel - ein Gateway für die Teilnahme von Nutzern konventioneller Telefonendgeräte an MBone-Konferenzen.
Conference or Workshop Item

Ackermann, Ralf ; Pommitz, J. ; Wolf, L. C. ; Steinmetz, Ralf (1999)
MBone2Tel - telephone users meeting the MBone.
Conference or Workshop Item

Rensing, Christoph ; Ackermann, Ralf ; Roedig, U. ; Wolf, L. C. ; Steinmetz, Ralf (1999)
Sicherheitsunterstützung für Internet Telefonie.
In: DUD-Fachbeiträge 1999, März. - Braunschweig: Vieweg, 1999. S. 285-296
Book Section

Rensing, Christoph ; Rödig, Utz ; Ackermann, Ralf ; Wolf, L. C. ; Steinmetz, Ralf (1999)
VDMFA: eine verteilte dynamische Firewallarchitektur für Multimedia-Dienste.
Conference or Workshop Item