Norbert Luttenberger - Academia.edu (original) (raw)

Papers by Norbert Luttenberger

International Journal On Advances in Software, Jun 30, 2014

Both OWL-2 and UML static class diagrams lend themselves very well for conceptual modelling of co... more Both OWL-2 and UML static class diagrams lend themselves very well for conceptual modelling of complex information systems. Both languages have their advantages. In order to benefit from the advantages and software tools of both languages, it is usually necessary to repeat the modelling process for each language. We have investigated whether and how conceptual models written in one language can be automatically transformed into models written in the other language. For this purpose we investigated differences and similarities of various model elements (such as element type, data types, relationship types) in static UML data models and OWL-2 ontologies. We provide a transformation for similar elements.

Mobile ad-hoc networks (MANETs) and especially mobile Wireless Sensor Networks (mWSNs) are embedd... more Mobile ad-hoc networks (MANETs) and especially mobile Wireless Sensor Networks (mWSNs) are embedded in the environment and therefore stand under strong influence of its specific characteristics. Beside e.g. sensor input, nodes motion patterns are supposed to be a very basic factor regarding performance. Hence simulations may need to account scenario specific mobility patterns while keeping the tradeoff related to simulation complexity in mind. This contribution proposes a graph based mobility model, designed to resemble probabilistic node movements according to real world node paths like they may be induced by road grids. The model is presented along with a real world mWSN sample deployment from which the paths are extracted and against which the simulation fine-tuned.

Adaptive bitonic sort is a well known merge-based parallel sorting algorithm. It achieves optimal... more Adaptive bitonic sort is a well known merge-based parallel sorting algorithm. It achieves optimal complexity using a complex tree-like data structure called a bitonic tree. Due to this, using adaptive bitonic sort together with other algorithms usually implies converting bitonic trees to arrays and vice versa. This makes adaptive bitonic sort inappropriate in the context of hybrid sorting algorithms where frequent switches between algorithms are performed. In this article we present a novel optimal sorting algorithm that is based on an approach similar to adaptive bitonic sort. Our approach does not use bitonic trees but uses the input array together with some additional information. Using this approach it is trivial to switch between adaptive bitonic sort and other algorithms. We present an implementation of a hybrid algorithm for GPUs based on bitonic sort and our novel algorithm. This implementation turns out to be the fastest comparison-based sorting algorithm for GPUs found in literature.

Automatisierungstechnik, 1992

Theorie für den Anwender Dr.-Ing. Norbert Luttenberger ist wissenschaftlicher Angestellter im Eur... more Theorie für den Anwender Dr.-Ing. Norbert Luttenberger ist wissenschaftlicher Angestellter im Europäischen Zentrum für Netzwerkforschung der IBM Deutschland GmbH. Hauptarbeitsfelder: Untersuchung der Leistungsfähigkeit von Kommunikationssystemen für Hochgeschwindigkeitsnetze.

Computer Communications, Apr 1, 1995

The integration of continuous presentation media like audio and video into current workstation an... more The integration of continuous presentation media like audio and video into current workstation and networking environments imposes tight timing constraints on A/V data transfer. These constraints are summarized under the term Quality of Service (QoS), which ...

Kommunikation in Verteilten Systemen, 2011

... Development Infrastructure for Distributed Embedded Systems Martin Lipphardt, Nils Glombitza,... more ... Development Infrastructure for Distributed Embedded Systems Martin Lipphardt, Nils Glombitza, Jana Neumann, Christian Werner, and ... as a Service (BaaS): Security and Performance Enhancements for the Rich Web Nils Gruschka and Luigi Lo Iacono ..... ...

Business & Information Systems Engineering, Sep 1, 2017

Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch ge... more Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen. Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in EconStor may be saved and copied for your personal and scholarly purposes. You are not to copy documents for public or commercial purposes, to exhibit the documents publicly, to make them publicly available on the internet, or to distribute or otherwise use the documents in public. If the documents have been made available under an Open Content Licence (especially Creative Commons Licences), you may exercise further usage rights as specified in the indicated licence.

Planning new railway infrastructures is a complex process. We present an approach where the forma... more Planning new railway infrastructures is a complex process. We present an approach where the formalization of expert knowledge regarding the railway domain is motivated in order to improve the planning process. By applying ontologies as a representation of railway related knowledge we are able to make the coherencies of infrastructural elements explicit. Furthermore the integration of an ontology-based rule language provides the possibility of a semi-automated integrity verification of static infrastructure and safety components. Semantical inconsistencies potentially leading to unsafe conditions regarding train operations can be spotted within this verification process. This combination of conceptualization and correlation rules tends to be applicable for the creation of a formal and consistent model of specific railway infrastructures which are to be planned.

In this case study we show how four topography-independent radio models (models not regarding ind... more In this case study we show how four topography-independent radio models (models not regarding individual obstacles in the operations area) can be "tuned" such that the outcomes of an event-driven network simulator come as close as possible to reference data obtained in a real-world radio network experiment. An evolutionary optimization process was applied to find near optimal parameter values four these models. We describe the optimization process, the error function that guides it and discuss the results.

Microprocessing and Microprogramming, Dec 1, 1986

Abstract To improve the performance of distributed systems, monitoring of communication activitie... more Abstract To improve the performance of distributed systems, monitoring of communication activities is often the first step. In this paper a VLSI-chip named Chained Reference Address Comparator (CRAC) is presented that supports the monitoring of procedure- and message-oriented communication in distributed MMC systems with shared memory. This is done by monitoring the accesses of processors to the data structures allocated in shared memory that serve communication purposes. A key capability of the CRAC chip is the program controlled address comparison technique featuring automatic generation of reference addresses from address elements dynamically acquired by the CRAC chip from the data bus of the monitored system. This so-called chained address comparison makes it possible to monitor structure accesses to dynamic data structures, having an important function for the implementation of communication mechanisms. Due to its direct attachement to the processor address/data bus it is specifically designed for MMC systems with the Intel processor 8086.

Positioning sensor nodes requires distance information to reference points. Due to resource limit... more Positioning sensor nodes requires distance information to reference points. Due to resource limitations in sensor networks, distance determination in low-cost sensor nodes without additional hardware is difficult. Known techniques such as distance estimation based on received signal strength (RSSI) are mostly inaccurate or have limitations. We propose a new method to measure the distance between a transmitting node and a receiving node using the minimal transmission power. The determined distance is more precise than RSSI, has a low variance and is therefore particularly suitable for positioning. Finally, we implemented a demonstrator application using weighted centroid localization to show the practical implementation.

Kluwer Academic Publishers eBooks, Jul 24, 2006

Though Web Services become more and more popular, not only inside closed intranets but also for i... more Though Web Services become more and more popular, not only inside closed intranets but also for inter-enterprise communications, few efforts have been made so far to secure a Web Service's availability. Existing security standards like e.g. WS-Security only address message integrity and confidentiality, and user authentication and authorization. In this article we present a system for protecting Web Services from Denial-of-Service (DoS) attacks. DoS attacks often rely on misformed andior overly long messages that engage a server in resource-consuming computations. Therefore, a suitable means to prevent such kinds of attacks is the full grammatical validation of messages by an application level gateway before forwarding them to the server. We discuss specific kinds of DoS attacks against Web Services, show how message grammars can automatically be derived from formal Web Service descriptions (written in the Web Service Description Language), and present an application level gateway solution called "Checkway" that uses these grammars to filter Web service messages. The paper closes by giving some performance figures for full grammatical validation.

A major advantage offered by Web services technologies is the ability to dynamically discover and... more A major advantage offered by Web services technologies is the ability to dynamically discover and invoke services. This ability is particularly important for operations of many applications executing in open dynamic environments. The QoS properties of the required and provided services play a significant role in dynamic discovery and invocation of services in open dynamic environments. In this paper, we discuss our approach to QoS specification and service provider selection, in the context of our work on the Dino project. The service provider selection algorithm used in Dino takes into account the relative benefit offered by a provider with respect to the requester-specified QoS criteria, and the trustworthiness of the provider. We explain our approach using an example from the automotive domain.

PIK. Praxis der Informationsverarbeitung und Kommunikation, 2013

PIK. Praxis der Informationsverarbeitung und Kommunikation, Mar 1, 2000

ZUSAMMENFASSUNG Für den Schutz der in einem Intranet betriebenen Server vor Angriffen aus dem Int... more ZUSAMMENFASSUNG Für den Schutz der in einem Intranet betriebenen Server vor Angriffen aus dem Internet und für die Aufrechterhaltung der Verfügbarkeit der entsprechenden Rechensysteme werden heute von vielen Intranet-Betreibern Firewall-Systeme eingesetzt. Firewall-Systeme lassen sich als Schutzsysteme betrachten, die den einzigen Verbindungspunkt eines Intranets zum Internet darstellen, und die jedweden ein- und ausgehenden Verkehr überwachen. Die Praxis hat gezeigt, daß sowohl die Formulierung von Überwachungsregeln für Firewall-Systeme als vor allem auch die Integration von Firewall-Funktionen und Intranet-Services komplizierte Probleme sind, die von den Netzwerkadministratoren oftmals eine sehr detaillierte Kenntnis der Funktionsweise aller eingesetzten Komponenten erfordern. In diesem Aufsatz wird ein integriertes Firewall-/Server-System vorgestellt, in dem durch die hardware- und softwaremäßige Integration von Firewall- und Server-Funktionen in einer black box der Aufbau eines Intranet erheblich vereinfacht werden kann. Das iFSS/5 bietet neben der Schutzfunktion sowohl externe Services für Benutzer aus dem Internet (z.B. einen WWW-Dienst), als auch strikt interne Dienste. Die Administration des gesamten Komplexes erfolgt über eine einheitliche, diensteorientierte graphische Benutzeroberfläche.

Instrumentation viewpoint, 2009

In this paper we present the steps followed in order to do the design of the OBSEA project websit... more In this paper we present the steps followed in order to do the design of the OBSEA project website, and also the technologies and mechanisms used to process and show the data acquired by the observatory. One of the main bases of our work plan was to take into account the destination public who the website is addressed to, both general public and scientists or engineers must find interesting contents. For the construction of this website we have used commercial programs and applications.

The ISO 19103 standard-defining rules and guidelines for conceptual modeling in the geographic do... more The ISO 19103 standard-defining rules and guidelines for conceptual modeling in the geographic domain-has deliberately chosen the Unified Modeling Language (UML) as "conceptual schema language" for geographic information systems. From today's perspective-i.e. when taking into account today's mature semantic web technology-another language might also be envisioned as language for specifying applicationoriented conceptual models, namely the Web Ontology Language OWL 2. Both language definitions refer to comparable meta-models laid down in terms of OMG's Meta Object Facility, but in contrast to UML, OWL 2 is fully built upon formal logic which allows logical reasoning on OWL 2 ontologies. In this paper, we investigate language similarities and differences by specifying and implementing the transformation on the meta-model level using the QVT transformation language.

Abstract A known weakness of Web Services is their vulner-ability to Denial of Service attacks e... more Abstract A known weakness of Web Services is their vulner-ability to Denial of Service attacks exploiting XML processing characteristics. To protect Web Services from these attacks, extended validation of SOAP messagesconsidering WS-Security and WS-SecurityPolicyis ...