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Displaying 1-50 out of 120 total
Keep It Small and Smart
Found in: Computer Systems and Applications, ACS/IEEE International Conference on
By Abdulmotaleb El Saddik, Ralf Steinmetz
Issue Date:June 2001
pp. 0538
Abstract: The production of interactive multimedia content is in most cases an expensive task in terms of time and cost. It must hence be the goal to optimize the production by exploiting the reusability of interactive multimedia elements. Reusability can ...
 
Enhanced SIP Communication Services by Context Sharing
Found in: EUROMICRO Conference
By Manuel Görtz, Ralf Ackermann, Ralf Steinmetz
Issue Date:September 2004
pp. 272-279
Communication plays a central in our society. It affects our private lives as well as business activities. Humans usually observe the environment and the communication partner with all their senses. The perceived information is evaluated to deduce the cont...
 
Using a Multi-Layer Approach to Tackle the Service Interaction Problem in Telephony Scenarios
Found in: EUROMICRO Conference
By Manuel Görtz, Ralf Ackermann, Martin Karsten, Ralf Steinmetz
Issue Date:September 2002
pp. 207
<p>The inauguration of IP telephony as a new and promising technology has opened the door to a variety of enhanced communication services and applications, which differ from those of the PSTN. The shift from circuit switched to packet-based networks,...
 
Reusability and adaptability of interactive resources in Web-based educational systems
Found in: Journal of Educational Resources in Computing (JERIC)
By Abdulmotaleb El Saddik, Ralf Steinmetz, Ralf Steinmetz, Stephan Fischer, Stephan Fischer, Abdulmotaleb El Saddik, Ralf Steinmetz, Stephan Fischer
Issue Date:March 2001
pp. 4-es
The production of interactive multimedia content is in most cases an expensive task in terms of time and cost. Hence, optimizing production by exploiting the reusability of interactive multimedia elements is mandatory. Reusability can be triggered by a com...
     
Content-Based Digital Signature for Motion Pictures Authentication and Content-Fragile Watermarking
Found in: Multimedia Computing and Systems, International Conference on
By Jana Dittmann, Arnd Steinmetz, Ralf Steinmetz
Issue Date:June 1999
pp. 209
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 image/video authentication and copyr...
 
Biometric Hash based on Statistical Features of Online Signatures
Found in: Pattern Recognition, International Conference on
By Claus Vielhauer, Ralf Steinmetz, Astrid Mayerhöfer
Issue Date:August 2002
pp. 10123
<p>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...
 
Perceived Consistency
Found in: Computer Systems and Applications, ACS/IEEE International Conference on
By Carsten Griwodz, Michael Liepert, Abdulmotaleb El Saddik, Giwon On, Michael Zink, Ralf Steinmetz
Issue Date:June 2001
pp. 0260
Abstract: Quality of service guarantees for multimedia communication systems have been considered on several abstraction levels. In the multimedia networking field it is typical to identify the minimal QoS requirements of an application to save resources b...
 
Push vs. Pull: An Energy Perspective (Short Paper)
Found in: 2013 IEEE 6th International Conference on Service-Oriented Computing and Applications (SOCA)
By Daniel Burgstahler,Ulrich Lampe,Nils Richerzhagen,Ralf Steinmetz
Issue Date:December 2013
pp. 190-193
In many application scenarios, such as traffic guidance or ambient living, services need to notify mobile applications about status changes. Such notifications to mobile devices can be realized using two principal approaches, namely push- and pull-based. A...
 
On the Accuracy of Time Measurements in Virtual Machines
Found in: 2013 IEEE 6th International Conference on Cloud Computing (CLOUD)
By Ulrich Lampe,Markus Kieselmann,Andre Miede,Sebastian Zoller,Ralf Steinmetz
Issue Date:June 2013
pp. 960-961
While cloud computing permits access to a large pool of experimental infrastructure, the most common form - virtual machines - has been shown to exhibit substantial deficits with respect to the accuracy of time measurements. In our ongoing work, we provide...
 
QoS-Aware, Cost-Efficient Selection of Cloud Data Centers
Found in: 2013 IEEE 6th International Conference on Cloud Computing (CLOUD)
By Ronny Hans,Ulrich Lampe,Ralf Steinmetz
Issue Date:June 2013
pp. 946-947
Cloud computing is increasingly used to deliver multimedia services with stringent Quality of Service (QoS) requirements, rather than simple infrastructure. Due to these requirements, the QoS-aware, cost-efficient selection of data centers arises as a new ...
 
Distributed data filtering in logistics wireless sensor networks based on transmission relevance
Found in: 2012 IEEE 37th Conference on Local Computer Networks (LCN 2012)
By Sebastian Zoller,Andreas Reinhardt,Ralf Steinmetz
Issue Date:October 2012
pp. 256-259
Energy-efficient operation is mandatory in wireless sensor networks due to the limited energy budget of sensor nodes. Considering the potential application of wireless sensor networks in logistics, cost efficiency is another major requirement due to high c...
 
Protecting IEEE 802.11s wireless mesh networks against insider attacks
Found in: 2012 IEEE 37th Conference on Local Computer Networks (LCN 2012)
By Andreas Reinhardt,Daniel Seither,Andre Konig,Ralf Steinmetz,Matthias Hollick
Issue Date:October 2012
pp. 224-227
IEEE 802.11s is an emerging standard for wireless mesh networks. Networks based on IEEE 802.11s directly benefit from existing security mechanisms in IEEE 802.11. This limits the attack surface of IEEE 802.11s significantly for adversaries that cannot auth...
 
Plug-and-Play Virtual Factories
Found in: IEEE Internet Computing
By Stefan Schulte,Dieter Schuller,Ralf Steinmetz,Sven Abels
Issue Date:September 2012
pp. 78-82
Although virtual factories are a well-established approach to managing distributed, cross-organizational manufacturing processes, corresponding end-to-end IT support is still lacking. Service-oriented virtual factories use and extend well-known methods and...
 
Supervising Knowledge Sharing in the Classroom: Supporting Teachers' Individual Diagnosis and Instruction in a Peer Education Scenario
Found in: 2012 IEEE 12th International Conference on Advanced Learning Technologies (ICALT)
By Kristina Richter,Regina Bruder,Johannes Konert,Stefan Gobel,Ralf Steinmetz
Issue Date:July 2012
pp. 503-505
Bridging the gap between diagnosis and learning in the classroom is the focus of our software tool PEDALE. It allows the usage of open-format questions, knowledge sharing and peer review of other students' solutions through the exchange of hand-written not...
 
Cost-Driven Optimization of Complex Service-Based Workflows for Stochastic QoS Parameters
Found in: 2012 IEEE 19th International Conference on Web Services (ICWS)
By Dieter Schuller,Ulrich Lampe,Julian Eckert,Ralf Steinmetz,Stefan Schulte
Issue Date:June 2012
pp. 66-73
The challenge of optimally selecting services from a set of functionally appropriate ones under Quality of Service (QoS) constraints -- the Service Selection Problem -- has been extensively addressed in the literature based on deterministic parameters. In ...
 
Maximizing Cloud Provider Profit from Equilibrium Price Auctions
Found in: 2012 IEEE 5th International Conference on Cloud Computing (CLOUD)
By Ulrich Lampe,Melanie Siebenhaar,Apostolos Papageorgiou,Dieter Schuller,Ralf Steinmetz
Issue Date:June 2012
pp. 83-90
Auctioning constitutes a market-driven scheme for the allocation of cloud-based computing capacities. It is practically applied today in the context of Infrastructure as a Service offers, specifically, virtual machines. However, the maximization of auction...
 
A cluster-based locality-aware mobile peer-to-peer architecture
Found in: Pervasive Computing and Communications Workshops, IEEE International Conference on
By Christian Gottron,Andro Konig,Ralf Steinmetz
Issue Date:March 2012
pp. 643-648
Mobile peer-to-peer networks combining a mobile ad hoc network underlay with a peer-to-peer overlay offer a flexible means for providing communication services in absence of a communication infrastructure. However, mobile peer-to-peer networks inherit seve...
 
Threat as a Service?: Virtualization's Impact on Cloud Security
Found in: IT Professional
By Hsin-Yi Tsai,Melanie Siebenhaar,André Miede,Yu-Lun Huang,Ralf Steinmetz
Issue Date:January 2012
pp. 32-37
Virtualization is essential to cloud computing, yet its security vulnerabilities in the cloud environment haven't been sufficiently studied. This analysis of cloud security focuses on how virtualization attacks affect different cloud service models.
 
Enabling cost-efficient Software Service Distribution in infrastructure clouds at run time
Found in: Service-Oriented Computing and Applications, IEEE International Conference on
By Ulrich Lampe,Thorsten Mayer,Johannes Hiemer,Dieter Schuller,Ralf Steinmetz
Issue Date:December 2011
pp. 1-8
Because Infrastructure as a Service in the form of virtual machines only provides a limited supply of resources per discrete instance, approaches are required to compute cost-efficient distribution strategies for Software as a Service instances. Due to its...
 
A Cross-Layer Approach towards Robustness of Mobile Peer-to-Peer Networks
Found in: Mobile Ad-Hoc and Sensor Systems, IEEE International Conference on
By Christian Gottron,André König,Ralf Steinmetz
Issue Date:October 2011
pp. 703-708
The lookup mechanism used to locate services in Peer-to-Peer systems can be attacked with little effort due to its decentralized and self-organizing nature. Security mechanisms aiming at rendering the lookup mechanism more robust mostly require a high amou...
 
Scoresheet-based event relevance determination for energy efficiency in wireless sensor networks
Found in: Local Computer Networks, Annual IEEE Conference on
By Sebastian Zoller,Andreas Reinhardt,Stefan Schulte,Ralf Steinmetz
Issue Date:October 2011
pp. 207-210
As wireless sensor nodes are mostly battery-powered, energy-efficient operation is a necessity to use their confined energy budget optimally. This is especially true in the logistics domain, where timely and accurate monitoring of containers is required, w...
 
SmartMeter.KOM: A low-cost wireless sensor for distributed power metering
Found in: Local Computer Networks, Annual IEEE Conference on
By Andreas Reinhardt,Dominic Burkhardt,Parag S. Mogre,Manzil Zaheer,Ralf Steinmetz
Issue Date:October 2011
pp. 1032-1039
Most current smart metering solutions aim at increasing user awareness for their household's electrical energy consumption. Although some smart meters make use of wireless data transfers between their sensor and display units, their integration into existi...
 
Enhancing the Caching of Web Service Responses on Wireless Clients
Found in: Web Services, IEEE International Conference on
By Apostolos Papageorgiou,Marius Schatke,Stefan Schulte,Ralf Steinmetz
Issue Date:July 2011
pp. 9-16
Contrary to simple Web content, standard Web services do not offer their clients the possibility to use cached information without the risk that it may be out-of-date. This feature has not been worth its costs in realistic Web service usage scenarios until...
 
Towards a P2P Cloud: Reliable Resource Reservations in Unreliable P2P Systems
Found in: Parallel and Distributed Systems, International Conference on
By Kalman Graffi, Dominik Stingl, Christian Gross, Hoang Nguyen, Aleksandra Kovacevic, Ralf Steinmetz
Issue Date:December 2010
pp. 27-34
The peer-to-peer paradigm shows the potential to provide the same functionality and quality like client/server based systems, but with much lower costs. However, the resources, e.g. storage space, CPU power and online time, provided by the peers are unreli...
 
Towards a Common Interface for Overlay Network Simulators
Found in: Parallel and Distributed Systems, International Conference on
By Christian Groß, Max Lehn, Dominik Stingl, Aleksandra Kovacevic, Alejandro Buchmann, Ralf Steinmetz
Issue Date:December 2010
pp. 59-66
Simulation has become an important evaluation method in the area of Peer-to-Peer (P2P) research due to the scalability limitations of evaluation test beds such as Planet Lab or G-Lab. Current simulators provide various abstraction levels for different unde...
 
Evaluating the QoS Impact of Web Service Anonymity
Found in: Web Services, European Conference on
By André Miede, Ulrich Lampe, Dieter Schuller, Julian Eckert, Ralf Steinmetz
Issue Date:December 2010
pp. 75-82
Web services enable the collaboration across organizational boundaries and, thus, are a powerful technology for implementing global Service-oriented Architectures, i.e., the Internet of Services. Despite typical security mechanisms such as message encrypti...
 
SFHC.KOM: Stateful header compression for wireless sensor networks
Found in: 2010 IEEE 35th Conference on Local Computer Networks (LCN 2010)
By Andreas Reinhardt,Parag S Mogre,Tobias Koenig,Ralf Steinmetz
Issue Date:October 2010
pp. 598-605
Nodes in wireless sensor networks are generally confined in the energy budget available for their operation, hence energy-aware application design is mandatory to achieve long node lifetimes. Radio transmissions represent an inherent, but energetically cos...
 
A concept for cross-layer optimization of wireless sensor networks in the logistics domain by exploiting business knowledge
Found in: 2010 IEEE 35th Conference on Local Computer Networks (LCN 2010)
By Sebastian Zöller,Andreas Reinhardt,Marek Meyer,Ralf Steinmetz
Issue Date:October 2010
pp. 935-937
Energy is limited in wireless sensor networks due to mostly battery-operated wireless sensor nodes. Consequently, an efficient energy usage significantly enhances the lifetime of a wireless sensor network. In this paper, we propose a cross-layer optimizati...
 
Study and Comparison of Adaptation Mechanisms for Performance Enhancements of Mobile Web Service Consumption
Found in: Services, IEEE Congress on
By Apostolos Papageorgiou, Jeremias Blendin, André Miede, Julian Eckert, Ralf Steinmetz
Issue Date:July 2010
pp. 667-670
Mobile Web services lie on the intersection of two big IT trends, namely Service-oriented Architectures (SOA) and mobile applications. So, their usage is likely to expand dramatically in the next years. However, the heavyweight nature of service-orientatio...
 
LOG4SWS.KOM: Self-Adapting Semantic Web Service Discovery for SAWSDL
Found in: Services, IEEE Congress on
By Stefan Schulte, Ulrich Lampe, Julian Eckert, Ralf Steinmetz
Issue Date:July 2010
pp. 511-518
In recent years, a number of approaches to semantic Web service matchmaking have been proposed. Most of these proposals are based on discrete and thus relatively coarse Degrees of Match (DoMs). However, different basic assumptions regarding the generalizat...
 
StreamSocial: A P2P streaming system with social incentives
Found in: A World of Wireless, Mobile and Multimedia Networks, International Symposium on
By Osama Abboud, Thomas Zinner, Eduardo Lidanski, Konstantin Pussep, Ralf Steinmetz
Issue Date:June 2010
pp. 1-2
P2P Streaming has attracted much attention recently with promises for more revenues and better load distribution. In parallel, social networking has changed how people interact using the web. One interesting use-case for next generation IPTV is Social TV. ...
 
QoS-Aware Service Composition for Complex Workflows
Found in: Internet and Web Applications and Services, International Conference on
By Dieter Schuller, Julian Eckert, André Miede, Stefan Schulte, Ralf Steinmetz
Issue Date:May 2010
pp. 333-338
In Service-oriented Architectures, business processes are realized by composing loosely coupled services. With the ongoing success of Web services technologies, the invocation of Web services goes beyond enterprises’ borders. So, besides implementing requi...
 
Enhancing Availability with Self-Organization Extensions in a SOA Platform
Found in: Internet and Web Applications and Services, International Conference on
By Apostolos Papageorgiou, Tronje Krop, Sebastian Ahlfeld, Stefan Schulte, Julian Eckert, Ralf Steinmetz
Issue Date:May 2010
pp. 161-166
The availability and reliability of Service-oriented architectures (SOA) depends on two factors: On the one hand, the availability and reliability of the services that provide a certain business functionality and on the other hand the services that make up...
 
Adaptive server allocation for peer-assisted Video-on-Demand
Found in: Parallel and Distributed Processing Workshops and PhD Forum, 2011 IEEE International Symposium on
By Konstantin Pussep,Osama Abboud,Florian Gerlach,Ralf Steinmetz,Thorsten Strufe
Issue Date:April 2010
pp. 1-8
Dedicated servers are an undesirable but inevitable resource in peer-assisted streaming systems. Their provision is necessary to guarantee a satisfying quality of experience to consumers, yet they cause significant, and largely avoidable cost for the provi...
 
Towards Seamless Binding of Context-aware Services to Ubiquitous Information Sources
Found in: Complex, Intelligent and Software Intensive Systems, International Conference
By Andreas Reinhardt, Johannes Schmitt, Farid Zaid, Parag S. Mogre, Matthias Kropff, Ralf Steinmetz
Issue Date:February 2010
pp. 69-74
The area of context-aware computing has received much attention in the last decade. However, many systems to determine a user’s context are focused on integrating a confined set of sensors into their decision-making algorithms, and lack extensibility for n...
 
A Generic Metamodel for IT Security
Found in: Availability, Reliability and Security, International Conference on
By André Miede, Nedislav Nedyalkov, Christian Gottron, André König, Nicolas Repp, Ralf Steinmetz
Issue Date:February 2010
pp. 430-437
Understanding and discussing the security aspects of IT systems during their development is challenging for both domain specialists and IT experts - neglecting this aspect leads to communication problems and, eventually, to less secure systems. An importan...
 
From Web Service Policies to Automatic Deviation Handling: Supporting Semantic Description of Reactions to Policy Violations
Found in: International Conference on Semantic Computing
By Stefan Schulte, Nicolas Repp, Dieter Schuller, Ralf Steinmetz
Issue Date:September 2009
pp. 312-317
In scenarios where Web services are involved, Quality of Service (QoS) parameters play an important role when it comes to service selection, service compositions, and run-time behavior of the execution environment, e.g. a workflow engine. Required or guara...
 
On the Implications of Adaptive Transmission Power for Assisting MANET Security
Found in: Distributed Computing Systems Workshops, International Conference on
By André König, Matthias Hollick, Ralf Steinmetz
Issue Date:June 2009
pp. 537-544
Mitigating misbehavior in mobile ad hoc networks (MANET) requires effective intrusion response systems. In this work, we present an intrusion response scheme that is tailored to support the infrastructure less nature of MANETs. We propose a geographic solu...
 
The Impact of Service Pricing Models on Service Selection
Found in: Internet and Web Applications and Services, International Conference on
By Julian Eckert, Deniz Ertogrul, Apostolos Papageorgiou, Nicolas Repp, Ralf Steinmetz
Issue Date:May 2009
pp. 316-321
Pricing of services, especially in a SOA and Grid environment with contractual relationships gain importance in recent years. For the resource planning, i.e. the allocation and orchestration of existing services, service pricing has a major influence. An o...
 
Underlay awareness in P2P systems: Techniques and challenges
Found in: Parallel and Distributed Processing Symposium, International
By Osama Abboud,Aleksandra Kovacevic,Kalman Graffi,Konstantin Pussep,Ralf Steinmetz
Issue Date:May 2009
pp. 1-8
Peer-to-peer (P2P) applications have recently attracted a large number of Internet users. Traditional P2P systems however, suffer from inefficiency due to lack of information from the underlay, i.e. the physical network. Although there is a plethora of res...
 
A Peer-to-Peer Recommender System with Privacy Constraints
Found in: Complex, Intelligent and Software Intensive Systems, International Conference
By Konstantin Pussep, Sebastian Kaune, Jonas Flick, Ralf Steinmetz
Issue Date:March 2009
pp. 409-414
A recommender system can be used to suggest users potentially interesting content based on their previous consumption behavior. Such services already became common in centralized systems, such as Amazon, and approaches exist for decentralized recommender s...
 
Modelling the Internet Delay Space Based on Geographical Locations
Found in: Parallel, Distributed, and Network-Based Processing, Euromicro Conference on
By Sebastian Kaune, Konstantin Pussep, Christof Leng, Aleksandra Kovacevic, Gareth Tyson, Ralf Steinmetz
Issue Date:February 2009
pp. 301-310
Existing approaches for modelling the Internet delay space predict end-to-end delays between two arbitrary hosts as static values. Further, they do not capture the characteristics caused by geographical constraints. Peer-to-peer (P2P) systems are, however,...
 
A Distributed Platform for Multimedia Communities
Found in: Multimedia, International Symposium on
By Kalman Graffi, Sergey Podrajanski, Patrick Mukherjee, Aleksandra Kovacevic, Ralf Steinmetz
Issue Date:December 2008
pp. 208-213
Online community platforms and multimedia content delivery are merging in recent years. Current platforms like Facebook and YouTube are client-server based which result in high administration costs for the provider. In contrast to that peer-to-peer systems...
 
Resource Planning Heuristics for Service-Oriented Workflows
Found in: Web Intelligence and Intelligent Agent Technology, IEEE/WIC/ACM International Conference on
By Julian Eckert, Deniz Ertogrul, André Miede, Nicolas Repp, Ralf Steinmetz
Issue Date:December 2008
pp. 591-597
Resource allocation and resource planning, especially in a SOA and Grid environment, become crucial. Particularly, in an environment with a huge number of workflow consumers requesting a decentralized cross-organizational workflow, performance evaluation a...
 
Towards Benchmarking of Structured Peer-to-Peer Overlays for Network Virtual Environments
Found in: Parallel and Distributed Systems, International Conference on
By Aleksandra Kovacevic, Kalman Graffi, Sebastian Kaune, Christof Leng, Ralf Steinmetz
Issue Date:December 2008
pp. 799-804
Network virtual environments (NVE) are an evolving trend combining millions of users in an interactive community. A distributed NVE platform promises to lower the administration costs and to benefit from research done in the peer-to-peer (p2p) domain. In o...
 
SkyEye.KOM: An Information Management Over-Overlay for Getting the Oracle View on Structured P2P Systems
Found in: Parallel and Distributed Systems, International Conference on
By Kalman Graffi, Aleksandra Kovacevic, Song Xiao, Ralf Steinmetz
Issue Date:December 2008
pp. 279-286
In order to ease the development and maintenance of more complex P2P applications, which combine multiple P2P functionality (e.g. streaming and dependable storage), we suggest to extend structured P2P systems with a dedicated information management layer. ...
 
WS-Re2Policy: A Policy Language for Distributed SLA Monitoring and Enforcement
Found in: Systems and Networks Communication, International Conference on
By Nicolas Repp, André Miede, Michael Niemann, Ralf Steinmetz
Issue Date:October 2008
pp. 256-261
Web service technology and the Service-oriented Architecture (SOA) paradigm have become state of the art for the integration of systems across enterprise boundaries. Here, a strong need for policies exists, which describe the Quality of Service delivered b...
 
Capture, Management, and Utilization of Lifecycle Information for Learning Resources
Found in: IEEE Transactions on Learning Technologies
By Lasse Lehmann, Tomas Hildebrandt, Christoph Rensing, Ralf Steinmetz
Issue Date:January 2008
pp. 75-87
Throughout their lifecycle, Learning Resources undergo a multitude of processes by being created, used, provided or re-used. However, in order to be reusable, a Learning Resource often has to be adapted for a new context of use. This in turn implies multip...
 
Understanding BitTorrent?s Suitability in Various Applications and Environments
Found in: Computing in the Global Information Technology, International Multi-Conference on
By Sebastian Kaune, Jan Stolzenburg, Aleksandra Kovacevic, Ralf Steinmetz
Issue Date:August 2008
pp. 256-262
Peer-to-peer systems have recently emerged as an attractive alternative to client/server approaches, especially in the area of content distribution. By efficiently leveraging the available upload bandwidth of the end users, BitTorrent becomes a de facto st...
 
On NAT Traversal in Peer-to-Peer Applications
Found in: Enabling Technologies, IEEE International Workshops on
By Konstantin Pussep, Matthias Weinert, Aleksandra Kovacevic, Ralf Steinmetz
Issue Date:June 2008
pp. 139-140
A widely used technique to overcome the shortage of unique public IP addresses is Network Address Translation (NAT), which hides several hosts behind a single public address. This method works smoothly with client-server architectures; however, it causes s...
 
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