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Dr.-Ing. André Herms

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Veröffentlichungen

Publish/Subscribe Middleware für Selbstorganisierende Drahtlose Multi-Hop-Netzwerke
André Herms and Michael Schulze, Workshop über Selbstorganisierende, Adaptive, Kontextsensitive verteilte Systeme, Wiesbaden, Germany, March, 2008
[abstract] [BibTeX]

Das Routing in Wireless Mesh Networks hat einen dynamischen und selbstorganisierenden Charakter. Allerdings erfolgt die Kommunikation auf Anwendungsebene adressbasiert, was eine statische Zuordnung von Kommunikationspartnern erfordert. Dies wirkt der dynamischen Struktur leider entgegen. In dieser Arbeit beschreiben wir die Verbindung der Publish/Subscribe-Middleware COSMIC mit dem Routing-Protokoll AWDS. Durch Verwendung von COSMIC können Anwendungen inhaltsbasiert kommunizieren und sind nicht mehr auf die Kenntnis von Adressen angewiesen. Es wird das Konzept beschrieben und mittels Simulation und realen Messungen evaluiert. Hierbei zeigen wir, dass Wireless Mesh Networks geeignet sind, um in einer P/S-Infrastruktur eingesetzt zu werden.
@inproceedings{cite:Herms2008a,
  author = {Herms, Andr{\'e} and Schulze, Michael},
  title = {Publish/Subscribe Middleware f{\"u}r Selbstorganisierende Drahtlose Multi-Hop-Netzwerke},
  booktitle = {{Workshop über Selbstorganisierende, Adaptive, Kontextsensitive verteilte Systeme}},
  year = {2008},
  url = {http://www.self-org.info/saks/2008/herms.pdf}
}

An Integrated Approach for Reliability and Dependability of Wireless Mesh Networks
Georg Lukas, André Herms, Svilen Ivanov, and Edgar Nett, 13th IEEE Workshop on Dependable Parallel, Distributed and Network-Centric Systems DPDNS '08, 2008
[abstract] [BibTeX]

Wireless Mesh Networks (WMNs) are gaining popularity in many application areas because of their low cost and high flexibility. Technically, a WMN forms a distributed network-centric system which aims to provide communication services to the application layer, but has no built-in dependability provisions. To make the network dependable, many problems have to be solved on different layers. With this paper, we describe our ongoing work to provide an integrated solution to increase the dependability of WMNs. Our approach combines network coverage planning on the physical layer, bandwidth management on the link layer and live network monitoring to improve the reliability, availability and maintainability of a WMN. We provide fine-grained means to improve the predictability of the network components, thus making the WMN more dependable. In this paper, we present first results of our work, and describe how they are interleaved.
@inproceedings{cite:LHIN2008,
  author = {Georg Lukas and Andr\'e Herms and Svilen Ivanov and Edgar Nett},
  title = {An Integrated Approach for Reliability and Dependability of Wireless Mesh Networks},
  booktitle = {13th IEEE Workshop on Dependable Parallel, Distributed and Network-Centric Systems DPDNS '08},
  year = {2008},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2008/dependable_wmn_camera_ready.pdf}
}

Real-Time Mesh Networks for Industrial Applications
André Herms, Edgar Nett, and Stefan Schemmer, Proceedings of 17th International Federation of Automatic Control World Congress (IFAC'08), Seoul, Korea, July 6-11, 2008
[abstract] [BibTeX]

Wireless LANs (IEEE 802.11) are increasingly used in industrial applications. They reduce cabling costs, increase flexibility and enable mobile applications for maintenance or logistics tasks. Mesh networks provide a self-configuring and -healing wireless backbone for large scale deployments (e.g. in process automation). This paper presents a routing algorithm which provides QoS in wireless mesh networks, thus leveraging their use in industrial applications. It allows reserving bandwidth for real-time flows based on measurements of the physically available bandwidth. Thus it fully utilizes the bandwidth while still preventing congestion. Simulation results demonstrate the reliability of the algorithm and its advantage over previous works.
@inproceedings{cite:Herms2008b,
  author = {Herms, Andr{\'e} and Nett, Edgar and Schemmer, Stefan},
  title = {Real-Time Mesh Networks for Industrial Applications},
  booktitle = {Proceedings of 17th International Federation of Automatic Control World Congress (IFAC'08)},
  year = {2008}
}

Preventing Admission Failures of Bandwidth Reservation in Wireless Mesh Networks
Andre Herms and Georg Lukas, Proceedings of Workshop on Radio Resource Management in Wireless Mesh Networks in The 6th ACS/IEEE International Conference on Computer Systenms and Applications (AICCSA'08), Qatar, April, 2008
[abstract] [BibTeX]

Quality of Service for wireless mesh networks is an often requested feature for various kinds of applications. A common approach is the hop-by-hop reservation of bandwidth for individual routes. In this paper we address the problems of the reservation on a single hop. In previous works we used simulation studies to show that various existing approaches suffer from inconsistencies that lead to admission failures. In this paper, we discuss the reasons for these failures and present a protocol for preventing them. This allows to significantly increase the reliability of established communication links in WMNs.
@inproceedings{cite:Herms2008,
  author = {Andre Herms and Georg Lukas},
  title = {Preventing Admission Failures of Bandwidth Reservation in Wireless Mesh Networks},
  booktitle = {Proceedings of Workshop on Radio Resource Management in Wireless Mesh Networks in The 6th ACS/IEEE International Conference on Computer Systenms and Applications (AICCSA'08)},
  year = {2008},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2008/RRMinMesh_2_Herms.pdf}
}

Heuristic constructive algorithms for open shop scheduling to minimize mean flow time
Heidemarie Bräsel, André Herms, Marc Mörig, Thomas Tautenhahn, Jan Tusch, and Frank Werner, European Journal of Operational Research volume 189, pp. 856-870, September, 2008
[abstract] [BibTeX]

In this paper, we consider the problem of scheduling n jobs on m machines in an open shop environment so that the sum of completion times or mean flow time becomes minimal. For this strongly NP-hard problem, we develop and discuss different constructive heuristic algorithms. Extensive computational results are presented for problems with up to 50 jobs and 50 machines, respectively. The quality of the solutions is evaluated by a lower bound for the corresponding preemptive open shop problem and by an alternative estimate of mean flow time. We observe that the recommendation of an appropriate constructive algorithm strongly depends on the ratio n/m.
@article{cite:Brasel2008,
  author = {Heidemarie Br{\"a}sel and Andr{\'e} Herms and Marc M{\"o}rig and Thomas Tautenhahn and Jan Tusch and Frank Werner},
  title = {Heuristic constructive algorithms for open shop scheduling to minimize mean flow time},
  journal = {European Journal of Operational Research},
  year = {2008},
  volume = {189},
  number = {3},
  pages = {856--870},
  doi = {doi:10.1016/j.ejor.2007.02.057}
}

Exploiting Publish/Subscribe Communication in Wireless Mesh Networks for Industrial Scenarios
André Herms, Michael Schulze, Jörg Kaiser, and Edgar Nett, Emerging Technologies in Factory Automation (ETFA '08), Proceedings of, pp. 1-8, Hamburg, Germany, September, 2008
[BibTeX] 

@inproceedings{cite:Herms2008c,
  author = {Andr{\'e} Herms and Michael Schulze and J{\"o}rg Kaiser and Edgar Nett},
  title = {Exploiting Publish/Subscribe Communication in Wireless Mesh Networks for Industrial Scenarios},
  booktitle = {Emerging Technologies in Factory Automation (ETFA '08), Proceedings of},
  year = {2008},
  pages = {1--8}
}

Feedback-controlled WLAN: Achieving Channel-Availability in Mesh Networks
Svilen Ivanov, Andre Herms, Edgar Nett, Daniel Mahrenholz, and Stefan Schemmer, 7th IEEE International Symposium on Network Computing and Applications (IEEE NCA08), 10 - 12 July, Cambridge, MA USA, 2008
[BibTeX] 

@inproceedings{Ivanov2008a,
  author = {Svilen Ivanov and Andre Herms and Edgar Nett and Daniel Mahrenholz and Stefan Schemmer},
  title = {Feedback-controlled WLAN: Achieving Channel-Availability in Mesh Networks},
  booktitle = {7th IEEE International Symposium on Network Computing and Applications (IEEE NCA08), 10 - 12 July, Cambridge, MA USA},
  year = {2008}
}

Experimental Validation of the ns-2 Wireless Model using Simulation, Emulation, and Real Network
Svilen Ivanov, André Herms, and Georg Lukas, Proceedings of the 4th Workshop on Mobile Ad-Hoc Networks (WMAN'07), pp. 433 - 444, Feb. 26. - March 2., 2007
[abstract] [BibTeX]

Wireless network research in the last years is often based on simulation.Ns-2 is a widely used wireless network simulation tool for this purpose.However, there are no published results about the accuracy of the ns-2 wireless model in the literature so far. In this paper we present a validation of the wireless model of ns-2 done by comparing the network characteristics of a simulated, an emulated, and a real wireless network. In order to show only the relevant differences, we have calibrated the radio propagation model of ns-2 to the real network and have used the same routing protocol implementation and the same application data traffic in all the compared networks. The results show that the packet delivery ratios, the connectivity graphs,and the packet latencies are represented in the model with an average error of 0.3 10 and 57% respectively. Based on these results we conclude that the packet delivery ratios, and network topologies are accurately represented in ns-2, once the simulation parameters are properly adjusted. The accuracy of the packet latencies is lower and therefore statements about latencies in the real network based on the simulation results have a lower validity. Based on these results we provide recommendations for future development of the ns-2.
@inproceedings{cite:Ivanov2007,
  author = {Svilen Ivanov and Andr\'e Herms and Georg Lukas},
  title = {Experimental Validation of the ns-2 Wireless Model using Simulation, Emulation, and Real Network},
  booktitle = {Proceedings of the 4th Workshop on Mobile Ad-Hoc Networks (WMAN'07)},
  publisher = {VDE Verlag},
  year = {2007},
  pages = {433 -- 444},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2007/wman07magdeburg.pdf}
}

Measurement-Based Detection of Interfering Neighbors for QoS in Wireless Mesh Networks
André Herms, Georg Lukas, and Svilen Ivanov, 16th IST Mobile and Wireless Communications Summit 2007, Proceedings of, 2007
[abstract] [BibTeX]

Communication in wireless mesh networks based on the IEEE~802.11 WLAN standard is mainly governed by the carrier sensing based medium access. Knowledge about, which nodes influence each other, can improve the performance and is essential for QoS provision in terms of bandwidth guarantees. However, until now only approximations for the determination of station in carrier sense range are used. We present an exact solution by measuring the carrier sense in static wireless mesh networks. Simulation studies and measurements are done that verify the correctness of the protocol and reveal some significant properties of the carrier sense. It is shown that the carrier sense relation is neither strict nor symmetric in the general case, in opposite to the assumptions normally found in literature. We further conclude that for evaluation better simulation models are required that match these properties.
@inproceedings{cite:Herms2007,
  author = {Andr\'e Herms and Georg Lukas and Svilen Ivanov},
  title = {Measurement-Based Detection of Interfering Neighbors for QoS in Wireless Mesh Networks},
  booktitle = {16th IST Mobile and Wireless Communications Summit 2007, Proceedings of},
  year = {2007},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2007/interf-mobilesummit2007.pdf},
  doi = {10.1109/ISTMWC.2007.4299081}
}

Interval based Off-Line Clock Synchronization for Wireless Mesh Networks
Georg Lukas, André Herms, and Daniel Mahrenholz, Proceedings of the International Symposium on Computer Performance, Modeling, Measurements, and Evaluation volume 35, 2007
[abstract] [BibTeX]

Wireless mesh networks suffer from various problems like congestion or packet collisions. To identify and overcome these problems an exact global view of the communication is required. However, it is not possible to observe the whole network from a single location. Instead, a distributed monitoring is necessary, which has to include clock synchronization. We present a new interval-based algorithm for the off-line synchronization of passively monitored network events. It calculates the worst-case time interval for every event on a global clock, while considering inaccuracies caused by processing jitter and non-uniform clock drifts. The experimental evaluation on a live mesh network shows an accuracy of better than $130µs$ over a four-hop distance, which is below the minimum transmission time of data packets. Thereby, our algorithm creates a highly precise global view of the network, which allows a detailed diagnosis of wireless mesh networks.
@inproceedings{cite:Perf2007,
  author = {Georg Lukas AND Andr\'e Herms AND Daniel Mahrenholz},
  title = {Interval based Off-Line Clock Synchronization for Wireless Mesh Networks},
  booktitle = {Proceedings of the International Symposium on Computer Performance, Modeling, Measurements, and Evaluation},
  publisher = {ACM},
  year = {2007},
  volume = {35},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2007/2007_performance-offlinesync.pdf}
}

A Pragmatic Approach for QoS in Wireless Multihop Networks
André Herms and Georg Lukas, International Conference on Wireless Information Networks and Systems -- WinsSys '07, Proceedings of, Bacelona, Spain, 2007
[abstract] [BibTeX]

In this paper we present a QoS routing protocol for IEEE-802.11 based mesh networks.The main challenge for providing QoS in terms of bandwidth and latency is that the medium is shared between all nodes in close range, which complicates reservation of medium time. Furthermore, the use of standard compliant hardware components requires an integration of the existing medium access mechanism, which is designed for best-effort communication only. A cluster-based structure is used for representing the local domains of the shared medium and allowing reservation of medium time. On top of this reservation an optimistic reactive algorithm is used for discovery and reservation of routes that fulfil the application specified QoS requirements. Simulation results are presented that prove the correctness of this approach.
@inproceedings{cite:Herms2007a,
  author = {Andr\'e Herms and Georg Lukas},
  title = {A Pragmatic Approach for {QoS} in Wireless Multihop Networks},
  booktitle = {International Conference on Wireless Information Networks and Systems -- {WinsSys} '07, Proceedings of},
  year = {2007},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2007/qos_clusters.pdf}
}

Echtzeitfähigkeit für Mesh-Netzwerke in der Automatisierung
André Herms, Stefan Schemmer, and Georg Lukas, Proceedings of SPS/IPC/DRIVES, Elektrische Automatisierung, Systeme und Komponenten '07, Nurenberg, Germany, November, 2007
[BibTeX] 

@inproceedings{cite:Herms2007b,
  author = {Andr{\'e} Herms and Stefan Schemmer and Georg Lukas},
  title = {{Echtzeitfähigkeit für Mesh-Netzwerke in der Automatisierung}},
  booktitle = {Proceedings of {SPS/IPC/DRIVES, Elektrische Automatisierung, Systeme und Komponenten} '07},
  year = {2007},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2007/sps2007-schemmer_v1.pdf}
}

Precise Admission Control for Bandwidth Reservation in Wireless Mesh Networks
André Herms, Svilen Ivanov, and Georg Lukas, Proceedings of 4th Intl. Conference on Mobile Ad-Hoc and Sensor Networks MASS'07, Pisa, Italy, October, 2007
[BibTeX] 

@inproceedings{cite:Herms2007c,
  author = {Andr\'e Herms and Svilen Ivanov and Georg Lukas},
  title = {Precise Admission Control for Bandwidth Reservation in Wireless Mesh Networks},
  booktitle = {Proceedings of 4th Intl. Conference on Mobile Ad-Hoc and Sensor Networks {MASS'07}},
  year = {2007}
}

Realism in Design and Evaluation of Wireless Routing Protocols
André Herms, Georg Lukas, and Svilen Ivanov, Proceedings of First international Workshop on Mobile Services and Personalized Environments (MSPE'06) volume P-102, pp. 57-70, Aachen, Germany, November, 2006
[abstract] [BibTeX]

In this paper we consider the problem of reliable communication in wireless routing protocols. Many routing protocols for wireless networks use assumptions, that are known to be invalid in this special kind of networks. These shortcomings are not detected in the protocol evaluation, because common simulation tools are also based on these assumptions. In this paper we present a more realistic simulation model and a simple way of enabling existing protocols to handle real conditions of wireless propagation. A proof-of-concept implementation is presented and evaluated using simulation and measurements in a real and emulated network.
@inproceedings{cite:awds06,
  author = {Andr\'e Herms and Georg Lukas and Svilen Ivanov},
  title = {Realism in Design and Evaluation of Wireless Routing Protocols},
  booktitle = {Proceedings of First international Workshop on Mobile Services and Personalized Environments (MSPE'06)},
  year = {2006},
  volume = {P-102},
  pages = {57--70},
  url = {http://ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2006/awds-mspe.pdf}
}

A comparison of heuristics for mean flow time open shop scheduling
Heidemarie Bräsel, André Herms, Marc Mörig, Thomas Tautenhahn, Jan Tusch, Frank Werner, and Per Willenius, 12th IFAC Symposium on Information Control Problems in Manufacturing, Proceedings of volume 12, 2006
[BibTeX] 

@inproceedings{cite:Brasel2006,
  author = {Heidemarie Br{\"a}sel and Andr{\'e} Herms and Marc M{\"o}rig and Thomas Tautenhahn and Jan Tusch and Frank Werner and Per Willenius},
  title = {A comparison of heuristics for mean flow time open shop scheduling},
  booktitle = {12th IFAC Symposium on Information Control Problems in Manufacturing, Proceedings of},
  year = {2006},
  volume = {12},
  number = {1}
}

Unified Development and Deployment of Network Protocols
André Herms and Daniel Mahrenholz, Proceedings of MeshNets Workshop in conjunction with First International Conference on Wireless Internet (WICON), Budapest, Hungary, July, 2005
[abstract] [BibTeX]

In this paper we describe GEA- an interface that enables the development of event-driven network protocols, their testing in a simulated network and deployment using a single, unmodified code. Normally testing and deployment requires separated implementations which results in a significant development and maintenance overhead. This is due to the different APIs of the underlying systems. As a solution to this problem we propose a common, generic event based interface called GEA. We present its design principles and show by example how to implement a network protocols with it. Finally we compare the execution of the protocol implementation in both environments to show the effectiveness of our approach.
@inproceedings{cite:Herms2005,
  author = {Andr\'e Herms and Daniel Mahrenholz},
  title = {Unified Development and Deployment of Network Protocols},
  booktitle = {Proceedings of MeshNets Workshop in conjunction with First International Conference on Wireless Internet (WICON)},
  year = {2005},
  url = {http://www-ivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/pdf/2005/gea.pdf}
}

Flexible Handling of System Software for Mobile Robots by using a Module Loader Concept
André Herms, Richard Bade, and Manfred Deutscher-Tiemann, Proceedings of Mechatronics & Robotics 2004, Aachen, Germany, September 13 - 15, 2004
[abstract] [BibTeX]

This paper describes the module loader concept. We successfully used this for the development of system software for our mobile robots. The module loader allows for organizing the software in modules. These can be loaded and removed at runtime. We describe how this is done. Additionally we give some examples on how to use the concept. Exemplified on our robot platforms we describe how to design and implement a modular system architecture.
@inproceedings{cite:Herms2004a,
  author = {Andr\'e Herms and Richard Bade and Manfred Deutscher-Tiemann},
  title = {Flexible Handling of System Software for Mobile Robots by using a Module Loader Concept},
  booktitle = {Proceedings of Mechatronics \& Robotics 2004},
  year = {2004},
  url = {http://www-ivs.cs.uni-magdeburg.de/EuK/mitarbeiter/ribade/mechrob2004_bade_deutscher_herms.pdf}
}

Motion Planning for a Legged Vehicle Based on Optical Sensor Information.
André Herms, Richard Bade, and Thomas Ihme, In Proceedings of CLAWAR 2004. 7th International Conference on Climbing and Walking Robots, pp. 971-979, Madrid, Spain, September, 2004
[abstract] [BibTeX]

This paper describes the motion planning for a walking robot based on environment information. The planning algorithm is based on random sampling. The environment information are generated by a stereo vision algorithm that has been modified to meet real-time requirements.
@inproceedings{cite:Herms2004,
  author = {Andr\'e Herms and Richard Bade and Thomas Ihme},
  title = {Motion Planning for a Legged Vehicle Based on Optical Sensor Information.},
  booktitle = {In Proceedings of CLAWAR 2004. 7th International Conference on Climbing and Walking Robots},
  year = {2004},
  pages = {971--979},
  url = {http://www-ivs.cs.uni-magdeburg.de/EuK/mitarbeiter/ribade/clawar2004_bade_herms_ihme.pdf},
  doi = {10.1007/3-540-29461-9}
}