Layer 1 team

2007

Berbner, R.; Spahn, M.; Repp, N.; Heckmann, O.; Steinmetz, R. (2007)

WSQoSX – A QoS architecture for Web Service workflows

In: 5th International Conference on Service-Oriented Computing (ICSOC 2007), Demo Track; Vienna, Austria

Category: Proceedings

Reference No.: 2007-726

Berbner, R.; Grollius, T.; Repp, N.; Eckert, J.; Heckmann, O.; Ortner, E.; Steinmetz, R. (2007)

Management of Service-oriented Architecture (SoA)-based Application Systems

In: Enterprise Modelling and Information Systems Architectures - An International Journal , Vol. 2, No. 1

Category: Publications in journals

Reference No.: 2007-640

Repp, N.; Berbner, R.; Eckert, J.; Heckmann, O.; Schulte, S.; Steinmetz, R. (2007)

Der Einfluß von Transportschicht-Anomalien auf die Performanz von Web Services

In: 15. Fachtagung Kommunikation in Verteilten Systemen (KiVS 2007); Bern

Category: Proceedings

Reference No.: 2007-430

Berbner, R.; Spahn, M.; Repp, N.; Heckmann, O.; Steinmetz, R. (2007)

Dynamic Replanning of Web Service Workflows

In: IEEE International Conference on Digital Ecosystems and Technologies 2007 (IEEE DEST 2007); Cairns, Australia

Category: Proceedings

Reference No.: 2007-429

Turczyk, L.; Heckmann, O.; Steinmetz, R. (2007)

Simulation of Information Lifecycle Management

In: 18th Annual Information Resources Management Association Conference (IRMA 2007); Vancouver, Canada

Category: Proceedings

Reference No.: 2007-425

Turczyk, L.; Heckmann, O.; Steinmetz, R. (2007)

File Valuation in Information Lifecycle Management

In: 18th Annual Information Resources Management Association Conference (IRMA 2007); Vancouver, Canada

Category: Proceedings

Reference No.: 2007-424

2006

Schmitt, J.; Heckmann, O.; König, A.; Hollick, M.; Steinmetz, R. (2006)

ENUM-Erweiterung zur Sicherung der Kommunikation zwischen VoIP-Infrastrukturen

In: Essener Workshop zur Netzwerksicherheit (EWNS); Essen

Category: Proceedings

Reference No.: 2006-553

Turczyk, L.; Gröpl, M.; Heckmann, O.; Steinmetz, R. (2006)

Statistische Datenanalyse von langfristigem Dateizugriffsverhalten

In: KOM Technical Report 09/2006

Category: Working papers

Reference No.: 2006-487

Eckert, J.; Schulte, S.; Heckmann, O.; Steinmetz, R. (2006)

Decentralized Workflows

In: KOM Technical Report 05/2006

Category: Working papers

Reference No.: 2006-486

Repp, N.; Berbner, R.; Heckmann, O.; Steinmetz, R. (2006)

A Cross-Layer Approach to Performance Monitoring of Web Services

In: Workshop on Emerging Web Services Technology (in conjunction with IEEE ECOWS 2006); Zürich

Category: Proceedings

Reference No.: 2006-419

Heckmann, O.; Gomez Sanchis, M.; Kovacevic, A.; Liebau, N.; Steinmetz, R. (2006)

A Peer-to-Peer System for Location-based Services

In: Americas Conference on Information Systems (AMCIS 2006); Acapulco, Mexico

Category: Proceedings

Reference No.: 2006-317

Heckmann, O. (2006)

The Competitive Internet Service Provider

In: Wiley & Sons

Category: Book

Reference No.: 2006-316

Heckmann, O. (2006)

Efficiency and Quality of Service of IP Networks

In: it - Information Technology Journal 3 (06): 177-180

Category: Publications in scientific journals

Reference No.: 2006-315

Darlagiannis, V.; Mauthe, A.; Heckmann, O.; Liebau, N.; Steinmetz, R. (2006)

On Routing in a Two-Tier Overlay Network based on de Bruijn Digraphs

In: IEEE/IFIP Network Operations and Management Symposium; Vancouver, Canada

Category: Proceedings

Reference No.: 2006-314

Berbner, R.; Spahn, M.; Repp, N.; Heckmann, O.; Steinmetz, R. (2006)

Heuristics for QoS-aware Web Service Composition

In: 4th IEEE International Conference on Web Services (ICWS 2006); Chicago, USA

Category: Proceedings

Abstract

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 select Web Services for each task so that the overall QoS and cost requirements of the composition are satisfied. Current proposals use exact algorithms or complex heuristics (e.g. genetic algorithms) to solve this problem. An actual implementation of a workflow engine (like our WSQoSX architecture), however, has to be able to solve these optimization problems in real-time and under heavy load. Therefore, we present a heuristic that performs extremely well while providing excellent (almost optimal) solutions. Using simulations, we show that in most cases our heuristic is able to calculate solutions that come as close as 99% to the optimal solution while taking less than 2% of the time of a standard exact algorithm. Further, we also investigate how much and under which circumstances the solution obtained by our heuristic can be further improved by other heuristics.

Reference No.: 2006-291

Repp, N.; Berbner, R.; Heckmann, O.; Steinmetz, R. (2006)

Digitized Handwritten Signatures replacing PIN/TAN

In: EFL Quarterly 1/2006; Frankfurt am Main

Category: Miscellaneous

Reference No.: 2006-148

Berbner, R.; Spahn, M.; Repp, N.; Heckmann, O.; Steinmetz, R. (2006)

An Approach for Replanning of Web Service Workflows

In: Americas Conference on Information Systems (AMCIS 2006); Acapulco, Mexico

Category: Proceedings

Abstract

The dynamic composition of Web Services to workflows at runtime is a major challenge in the emerging field of Service-oriented computing. At this, preferences and constraints defined by the user have to be considered, e.g. executing a workflow with the cheapest Web Services, but not exceeding a given execution time. Due to the volatile nature of the Web Service environment the actual runtime behavior of Web Services may deviate from the one estimated in the planning phase. Thus, replanning mechanisms are crucial for adapting a workflow to the real behavior ensuring that its execution remains feasible, valid and optimal subject to the preferences and constraints defined by the user. Replanning mechanisms have to perform in real-time not to create further delay to the workflow execution. Thus, in this paper, we introduce a heuristic based replanning mechanism.

Reference No.: 2006-110

Repp, N.; Berbner, R.; Perez, A.; Heckmann, O.; Steinmetz, R. (2006)

Die eigenhändige Unterschrift im Multichannel Banking

In: Thema Forschung, Technische Universität Darmstadt

Category: Other publications

Abstract

The article describes the application of digital handwritten signatures in multichannel banking scenarios. Digital handwritten signatures can be used for the integration of different channels in multichannel banking. The article discusses the use of this biometrical approach in an online banking scenario.

Reference No.: 2006-90

Berbner, R.; Repp, N.; Heckmann, O.; Steinmetz, R. (2006)

SoA zum Durchbruch verhelfen

In: IT-Management, Ausgabe 3, 2006

Category: Publications in journals

Reference No.: 2006-81

Turczyk, L.; Heckmann, O.; Berbner, R.; Steinmetz, R. (2006)

An Analytical Model of Information Lifecycle Management

In: IRMA 2006; Washington, USA

Category: Proceedings

Reference No.: 2006-19

Repp, N.; Berbner, R.; Lenz, J.; Kaplan, C.; Perez, A.; Heckmann, O.; Steinmetz, R. (2006)

Digitalisierte eigenhändige Unterschrift im Online-Banking

In: D-A-CH Security 2006; Düsseldorf

Category: Proceedings [Password Protected Download] (Please contact the author)

Abstract

Online-Banking stellt eine einfache Methode dar, seine Bankgeschäfte von zu Hause aus erledigen zu können. Weitere Vorteile des Online-Bankings sind sowohl für Bankkunden als auch die anbietende Bank selbst die niedrigen Transaktionskosten, die im Rahmen des Online-Bankings anfallen. Allerdings sind in der letzten Zeit Online-Banking-Systeme wegen massiver Sicherheitsprobleme in Verruf geraten. Gerade Systeme, die auf PIN und TAN basieren, weisen eine Reihe von Sicherheits- und Akzeptanzproblemen auf. Die Probleme im Online-Banking basieren zu einem nicht unerheblichen Anteil darauf, dass den Benutzern im Internet ein ausgeprägtes Sicherheitsbewusstsein fehlt. PIN und TAN stellen abstrakte Konstrukte zur Authentifizierung und Autorisierung dar, deren potentielles Missbrauchspotential den Benutzern oftmals nicht bewusst ist. Dieser Beitrag beschreibt einen Ansatz, die eigenhändige Unterschrift als Ergänzung oder Ersatz für Authentifizierung und Autorisierung im Online-Banking einzusetzen. Das Leisten einer Unterschrift ist dem Benutzer als Form der Autorisierung und Erklärung des Einverständnisses bekannt und die potentiellen Risiken bewusst. Weiterhin wird in diesem Beitrag ein Prototyp vorgestellt, der den Einsatz der eigenhändigen Unterschrift im Online-Banking realisiert. Teile der Arbeit entstanden mit Unterstützung des E-Finance Lab e.V., Frankfurt am Main (http://www.efinancelab.de).

Reference No.: 2006-17

Turczyk, L.; Heckmann, O.; Berbner, R.; Steinmetz, R. (2006)

A Formal Approach to Information Lifecycle Management

In: IRMA 2006, Washington, USA; Washington

Category: Proceedings

Reference No.: 2006-16

2005

Turczyk, L.; Gostner, R.; Berbner, R.; Heckmann, O.; Steinmetz, R. (2005)

Analyse von Datei-Zugriffen zur Potentialermittlung für Information Lifecycle Management

In: KOM Technical Report 01/2005

Category: Working papers

Reference No.: 2005-348

Mauthe, A.; Heckmann, O. (2005)

Peer-to-Peer and GRID Computing

In: Networking and Electronic Commerce Research Conference (NAEC 2005); Lake Garda, Italy

Category: Proceedings

Reference No.: 2005-322

Darlagiannis, V.; Mauthe, A.; Heckmann, O.; Liebau, N.; Steinmetz, R. (2005)

Asymmetric Incentives in Peer-to-Peer Systems

In: Proceedings of AMCIS 2005

Category: Proceedings

Reference No.: 2005-320

Birck, H.; Heckmann, O.; Steinmetz, R. (2005)

The Two-Step P2P Simulation Approach

In: Journal of Communication Software and Systems (JCOMSS)

Category: Publications in scientific journals

Reference No.: 2005-319

Fidler, M.; Heckmann, O.; Steinmetz, R. (2005)

Preserving the Independence of Flows in General Topologies Using Turn-Prohibition

In: Proceedings of IWQoS 2005, pages 193-205; Passau, Germany

Category: Proceedings

Reference No.: 2005-219

Berbner, R.; Heckmann, O.; Steinmetz, R. (2005)

Management of Service-oriented Architectures (SoA) within the E-Finance Industry

In: EFL Quarterly; Frankfurt am Main

Category: Miscellaneous

Reference No.: 2005-215

Heckmann, O.; Schmitt, J. (2005)

Best-Effort versus Reservations Revisited

In: Proceedings of IWQoS 2005, pages 151-163; Passau, Germany

Category: Proceedings

Reference No.: 2005-214

Heckmann, O.; Liebau, N.; Darlagiannis, V.; Bock, A.; Mauthe, A.; Steinmetz, R. (2005)

A Peer-to-Peer Content Distribution Network

In: From Integrated Publication and Information Systems to Information and Knowledge Environments: Essays Dedicated to Erich J. Neuhold on the Occasion of His 65th Birthday, volume 3379 of Lecture Notes in Computer Science, pages 69-78. Springer-Verlag GmbH,

Category: Chapter in book

Reference No.: 2005-213

Darlagiannis, V.; Liebau, N.; Heckmann, O.; Mauthe, A.; Steinmetz, R. (2005)

Caching Indices for Efficient Lookup in Structured Overlay Networks

In: Proceedings of Fourth International Workshop on Agents and Peer-to-Peer Computing, Springer

Category: Publications in scientific journals

Reference No.: 2005-212

Berbner, R.; Heckmann, O.; Steinmetz, R. (2005)

An Architecture for a QoS driven composition of Web Service based Workflows

In: Networking and Electronic Commerce Research Conference (NAEC 2005); Lake Garda, Italy

Category: Proceedings

Abstract

In times of globalisation and internationalisation enterprises have to establish flexible business processes to react to dynamically changing markets and to satisfy sophisticated customers. IT architectures that support the integration of legacy systems as well as the collaboration with business partners are a key success factor for flexible business processes. Thus, we present an approach to support flexible business processes by the means of a Service-oriented Architecture (SoA). Web Services as a realization of a Service-oriented Architecture gain more and more in importance to implement business processes. We address Quality of Service (QoS) as crucial for a sustainable success of Web Service based workflows. Thus, we designed and implemented a Web Service architecture with comprehensive QoS support. The selection of a particular Web Service depends on its QoS properties that must be guaranteed in Service Level Agreements (SLAs). The compliance with such SLAs is monitored by a component of the architecture as well.

Reference No.: 2005-81

Berbner, R.; Heckmann, O.; Mauthe, A.; Steinmetz, R. (2005)

Eine Dienstgüte unterstützende Web-Service-Architektur für flexible Geschäftsprozesse

In: WIRTSCHAFTSINFORMATIK 47 (2005) 4

Category: Publications in scientific journals [Password Protected Download] (Please contact the author)

Abstract

Webservices as a technology to enable distributed business processes gain in importance. However, the support of Quality of Service (QoS) is crucial in this context. Thus, we present an integrated Webservice architecture with comprehensive QoS support. The architecture we introduce in this paper supports the assessment of Webservices to assure that only Webservices will be used in critical business processes that satisfy the requirements defined by the user. The selection and execution of a certain Webservice depends on its QoS-properties that must be guaranteed in Service Level Agreements (SLAs). The compliance with SLAs is monitored by the system as well. Furthermore we introduce a prototypical implementation of our Webservice architecture.

Reference No.: 2005-80

2004

Birck, H.; Heckmann, O.; Mauthe, A.; Steinmetz, R. (2004)

Analysis of Overlay Networks at Message- and Packet-Level

In: Technical Report KOM-TR-2004-03

Category: Working papers

Reference No.: 2004-219

Heckmann, O. (2004)

A System-oriented Approach to Efficiency and Quality of Service for Internet Service Providers

Category: Dissertation thesis

Reference No.: 2004-174

Birck, H.; Heckmann, O.; Mauthe, A.; Steinmetz, R. (2004)

The Two-Step Overlay Network Simulation Approach

In: Proceedings of SoftCOM; Split (Croatia)

Category: Proceedings

Reference No.: 2004-173