Abhishek Dhama

Contact Details

    Work:      Carl von Ossietzky Universitaet

                   Department fuer Informatik

                   26111 Oldenburg(Oldb.)

                   Germany

    Phone:    +49 (0)441 798 46 69 

    Fax:        +49 (0)441 798  27 56

    Email:      <firstname>DOT<lastname>ATinformatik.uni-oldenburg.de

 Research Interests

      I am primarily interested in:

• Self-stabilizing Systems
• Quantitative evaluation of self-stabilizing systems
• Autonomic Computing

Projects

•  Transregional Collaborative Research Center 14 AVACS

        - Dependability Engineering of Self-stabilizing Systems

          Short Description. This project is aimed at developing rigorous methods to quantify and improve the relavant properties
          of self-stabilizing systems. In order to make the design of self-stabilizing systems viable
          for non-specialists, these methods also need to be automatized to the extent possible. The
          underlying models for the analysis and re-engineering methods are Discrete time Markov chains (DTMC)
          and Discrete time Markov Processes (DTMDP).

          An inherent challenge while analysing self-stabilizing systems is the fact that the set of initial
          states is equal to the set of states. Thus, we develop abstraction schemes and semantic models to
          overcome this difficulty during the analysis. It is not possible to design a single all encompassing
          procedure for the whole class of self-stabilizing systems. Due to this reason we aim to classify the
          self-stabilizing systems according to behavior and to devise proof obligations for each sub-class of
          self-stabilizing systems. We also propose fault tolerance metrics to quantify the behavior of self-stabilizing
          systems in an implementation scenario. It is often the case, that due to lack of implementation knowledge
          a self-stabilizing system might not meet desired fault tolerance threshold. Thus, it is important to use
          this knowledge of implementation scenario to engineer the system accordingly. In scope of this project
          we use counterexamples provided by the analysis methods to re-engineer the system such that it meet its
              QoS requirements . We also intend to provide heuristics so
          that one can map state space scenarios  in a counterexample to a modification protocol to improve the  

          fault tolerance metric.

 

Publications

• Jens Oehlerking, Abhishek Dhama und Oliver Theel
  "Towards Automatic Convergence Verification of Self-stabilizing Algorithms"
  In Ted Herman and Sébastien Tixeuil (ed.): Proceedings of 7th International Symposium on Self-Stabilizing Systems (SSS), Springer, Lecture Notes in Computer Science, Vol. 3764, S. 198-213, 2005
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{OeDT:convlyp:2005,
    author = {Jens Oehlerking and Abhishek Dhama and Oliver Theel},
    title = {Towards Automatic Convergence Verification of Self-stabilizing Algorithms},
    booktitle = {Proceedings of 7th International Symposium on Self-Stabilizing Systems (SSS)},
    publisher = {Springer},
    year = {2005},
    volume = {3764},
    pages = {198--213}
  }
  

  
  
  
• Abhishek Dhama, Jens Oehlerking und Oliver Theel
  "Verification of Orbitally Self-Stabilizing Distributed Algorithms using Lyapunov Functions and Poincaré Maps"
  In Proceedings of 12th International Conference on Parallel and Distributed Systems (ICPADS), IEEE Computer Society, S. 23-30, 2006
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{DhOeTh:orbitslfstbly:2006,
    author = {Abhishek Dhama and Jens Oehlerking and Oliver Theel},
    title = {Verification of Orbitally Self-Stabilizing Distributed Algorithms using Lyapunov Functions and Poincaré Maps},
    booktitle = {Proceedings of 12th International Conference on Parallel and Distributed Systems (ICPADS)},
    publisher = {IEEE Computer Society},
    year = {2006},
    pages = {23--30}
  }
  

  
  
  
• Abhishek Dhama, Oliver Theel und Timo Warns
  "Reliability and Availability Analysis of Self-stabilizing Systems"
  In Ajoy Kumar Datta and Maria Gradinariu (ed.): Proceedings of 8th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)

  ,, Springer, Lecture Notes in Computer Science, Vol. 4280, S. 244-261, 2006
  
  [BibTeX]

  
  BibTeX:

  @inproceedings{DhTW:relsss:2006,
    author = {Abhishek Dhama and Oliver Theel and Timo Warns},
    title = {Reliability and Availability Analysis of Self-stabilizing Systems},
    booktitle = {Proceedings of 8th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)
   ,},
    publisher = {Springer},
    year = {2006},
    volume = {4280},
    pages = {244--261}
  }
  

  
  
  
• Nils Müllner, Abhishek Dhama und Oliver Theel
  "Derivation of Fault Tolerance Measures of Self-Stabilizing Algorithms by Simulation"
  In Proceedings of 41st Annual Simulation Symposium (ANSS), IEEE Computer Society, S. 183-192, 2008
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{MueDT:sim:2008,
    author = {Nils Müllner and Abhishek Dhama and Oliver Theel},
    title = {Derivation of Fault Tolerance Measures of Self-Stabilizing Algorithms by Simulation},
    booktitle = {Proceedings of 41st Annual Simulation Symposium (ANSS)},
    publisher = {IEEE Computer Society},
    year = {2008},
    pages = {183--192}
  }
  

  
  
  
• Abhishek Dhama, Oliver Theel, Pepijn Crouzen, Holger Hermanns, Ralf Wimmer und Bernd Becker
  "Dependability Engineering of Silent Self-stabilizing Systems"
  In Rachid Guerraoui and Franck Petit (ed.): Proceedings of 11th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS), Springer, Lecture Notes in Computer Science, Vol. 5873, S. 238-253, 2009
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{DT+:depengsss:2009,
    author = {Abhishek Dhama and Oliver Theel and Pepijn Crouzen and Holger Hermanns and Ralf Wimmer and
   Bernd Becker},
    title = {Dependability Engineering of Silent Self-stabilizing Systems},
    booktitle = {Proceedings of 11th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)},
    publisher = {Springer},
    year = {2009},
    volume = {5873},
    pages = {238--253}
  }
  

  
  
  
• Abhishek Dhama und Oliver Theel
  "A Tranformational Approach for Designing Scheduler-Oblivious Self-stabilizing Algorithms"
  In Shlomi Dolev, Jorge Arturo Cobb, Michael J. Fischer and Moti Yung (ed.): Proceedings of 12th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS), Springer, Lecture Notes in Computer Science, Vol. 6366, S. 80-95, 2010
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{DhTh:rankxform:2010,
    author = {Abhishek Dhama and Oliver Theel},
    title = {A Tranformational Approach for Designing Scheduler-Oblivious Self-stabilizing Algorithms},
    booktitle = {Proceedings of 12th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)},
    publisher = {Springer},
    year = {2010},
    volume = {6366},
    pages = {80--95}
  }
  

  
  
  
• Ralf Wimmer, Bettina Braitling, Bernd Becker, Ernst Moritz Hahn, Pepijn Crouzen, Holger Hermanns, Abhishek Dhama und Oliver Theel
  "Symblicit Calculation of Long-Run Averages for Concurrent Probabilistic Systems"
  In Proceedings of the 7th International Conference on Quantitative Evaluation of Systems (QEST), IEEE Computer Society, S. 27-36, 2010
  
  [BibTeX]
  
  BibTeX:

  @inproceedings{wimmer-et-al-qest-2010,
    author = {Ralf Wimmer and Bettina Braitling and Bernd Becker and Ernst Moritz Hahn and Pepijn Crouzen and Holger Hermanns and Abhishek Dhama and Oliver Theel},
    title = {Symblicit Calculation of Long-Run Averages for Concurrent Probabilistic Systems},
    booktitle = {Proceedings of the 7th International Conference on Quantitative Evaluation of Systems (QEST)},
    publisher = {IEEE Computer Society},
    year = {2010},
    pages = {27--36}
  }