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Auflistung nach Autor:in "Nebel, Wolfgang"

1 - 8 von 8
  • Konferenzbeitrag
    A Data Center Simulation Framework Based on an Ontological Foundation
    (Proceedings of the 28th Conference on Environmental Informatics - Informatics for Environmental Protection, Sustainable Development and Risk Management, 2014) Memari, Ammar; Vornberger, Jan; Marx Gómez, Jorge; Nebel, Wolfgang
    The IT-for-Green project aims at developing the next generation of Corporate Environmental Management Information Systems (CEMIS). Green IT being one important aspect of this, the ITfor- Green project seeks to support the analysis of a given data center situation and to support the simulation of alternative architectures to find ways to increase energy efficiency. To facilitate this, we develop a data center simulation framework, designed to be part of a larger CEMIS platform. This is achieved through a focus on flexibility, high interoperability and open standards. Flexibility is especially achieved by building the framework on top of an underlying data center ontology. This ontological approach allows us to derive many components of the framework from a single source, maintaining the ability to quickly adapt to future requirements.
  • Zeitschriftenartikel
    Abstraction NBTI model
    (it - Information Technology: Vol. 63, No. 4, 2021) Adolf, Stephan; Nebel, Wolfgang
    Negative Bias Temperature Instability (NBTI) is one of the major transistor aging effects, possibly leading to timing failures during run-time of a system. Thus one is interested in predicting this effect during design time. In this work an Abstraction NBTI model is introduced reducing the state space of trap-based NBTI models using two abstraction parameters, applying a state transformation to incorporate variable stress conditions. This transformation is faster than traditional approaches. Currently the conversion into estimated threshold voltage damages is a very time consuming process.
  • Konferenzbeitrag
    Expansion of Data Center’s Energetic Degrees of Freedom to Employ Green Energy Sources
    (Proceedings of the 28th Conference on Environmental Informatics - Informatics for Environmental Protection, Sustainable Development and Risk Management, 2014) Janacek, Stefan; Nebel, Wolfgang
    Rising power consumption of data centers is a topic of great concern and therefore several power saving technologies exist. This paper describes the idea of a data center overall power saving and controlling strategy, allowing the data center to enter optimized minimum power states but also to control its own power consumption to apply demand response management. Therefore, the degrees of freedom a virtualized data center has are modelled and the methodology used to control its energy state is described, taking into account the IT hardware like servers and network gear as well as the influence of cooling devices and power distribution devices. In the paper, we describe our models used for our simulations, the methodology and the power saving potential of our system. We formulate the problem to control the data center’s power consumption by applying different consolidation strategies as an extended bin packing optimization problem, where virtual machines must be packed on a specific number of servers. External constraints like the time-flexibility of the solution and the influence on supporting devices are applied by using cost functions. We present a greedy solver for this problem and show first results and the potential of the entire approach.
  • Zeitschriftenartikel
    Green IT: Ein Thema für die Wirtschaftsinformatik?
    (Wirtschaftsinformatik: Vol. 53, No. 4, 2011) Loos, Peter; Nebel, Wolfgang; Marx Gómez, Jorge; Hasan, Helen; Watson, Richard T.; Brocke, Jan; Seidel, Stefan; Recker, Jan
  • Konferenzbeitrag
    Green-IT - Opportunities and challenges
    (Informatik 2009 – Im Focus das Leben, 2009) Nebel, Wolfgang
  • Konferenzbeitrag
    Kommunikationsgetriebene Hardware-/Software Partitionierung eines Netzwerkprotokoll-Stacks auf einer SoC Plattform
    (Informatk 2005. Informatik Live! Band 1, 2005) Grüttner, Kim; Beth, Carsten; Nebel, Wolfgang
    Dieses Paper beschreibt eine Untersuchung verschiedener HW/SW-Partitionierungen am Beispiel des LonTalk®-Protokollstacks. Ausgehend von einer maximalen Softwareimplementierung wird einerseits eine Verlagerung der Funktionalität von Softin Hardware, andererseits eine Veränderung der HW/SW-Schnittstelle und der Kommunikations-Architektur untersucht. Zur Evaluation wurde ein Altera Excalibur mit einem ARM9-Prozessorkern und integriertem FPGA benutzt.
  • Konferenzbeitrag
    OOCOSIM - Eine objekt-orientierte Co-Designmethode für eingebettete Hardware/Softwaresysteme
    (Informatik 2005 – Informatik Live! Band 2, 2005) Oppenheimer, Frank; Kersten, Michael; Nebel, Wolfgang
    Die steigende Komplexität von eingebetteten Systemen und die daraus resultierenden Designprobleme unterstreichen die Notwendigkeit von verbesserten Entwurfsmethoden. Dieser Artikel präsentiert eine objekt-orientierte Entwurfsmethode namens OOCOSIM, die diese Probleme adressiert. Für die Analyse bietet sie die graphische Notation namens HRT-HOOD+. Diese Beschreibungsform ermöglicht den Überblick und die Analyse von komplexen HW/SW-Systemen. Darüber hinaus wurde untersucht, inwieweit UML geeignet ist, die Beschränkungen von HRT-HOOD+ zu überwinden. Zur Überprüfung des Verhaltens der Systemmodelle wurde ein Konzept zur zeitsynchronen Co-Simulation entwickelt.
  • Konferenzbeitrag