Dipl.-Ing.-Inf. Timo Lindhorst

Former Assistant

Otto-von-Guericke-University Magdeburg

| 2015 | 2014 | 2013 | 2011 | 2010 | 2009 | 2008 |

2015

Timo Lindhorst, Edgar Nett
Dependable communication for mobile robots in industrialwireless mesh networks
In: Cooperative Robots and Sensor Networks 2015. - Cham [u.a.] : Springer International Publ., S. 207-227 - (Studies in Computational Intelligence; 604) ; ISBN: 978-3-319-18299-5 DOI: 10.1007/978-3-319-18299-5_10
http://www.springerprofessional.de/010---dependable-communication-for-mobile-robots-in-industrial-wireless-mesh-networks/5739414.html
Mobile robots inevitably require a wireless network for communication. Wireless mesh networks (WMNs) allow for increased flexibility and an easy integration of mobile robots. Hence, they are well suited for present and future cyber-physical industrial applications. The high dependability requirements of that application domain, however, issue particular challenges to the communication network, especially regarding the mobility of stations. In this chapter, we present various approaches and mechanisms to provide dependable communication for mobile robots in industrial WMNs. These comprise different cross-layer techniques to allow for seamless mobility and an admission control that explicitly considers station mobility to avoid network overload. Evaluation results are gathered by both simulation and real-world experiments while case-studies supplement the results. The outcome is a network architecture that allows for seamless communication even for mission-critical applications on mobile robots.

2014

Timo Lindhorst, Burkhard Weseloh, Edgar Nett
Dependable Admission Control for Mission-Critical Mobile Applications in Wireless Mesh Networks
Proceedings of the 33rd IEEE Symposium on Reliable Distributed Systems
Wireless Mesh Networks (WMNs) provide a promising foundation for a flexible
and reliable communication infrastructure in industrial environments. Meeting
the QoS demands of industrial applications, though, requires the deployment of
an admission control to avoid network overload. The presence of mobile
stations, however, causes dynamics within the network that severely impacts
the available capacity. For instance, if a communication route switches from
one to two hops, twice the resources are consumed due to self-interference. To
neither jeopardize QoS guarantees nor having to cancel present flows, our
dependable admission control scheme foresees and considers those dynamics
during resource reservation to handle station mobility.
We describe a highly dependable approach and further propose an estimation
method that improves network efficiency. The evaluation results show that our
novel approach allows for a dependable admission control even in presence of
mobile stations and thus enables the network to provide a new class of
guarantee for mission-critical mobile applications.
@InProceedings{srds14,
  Title                    = {Dependable Admission Control for Mission-Critical Mobile Applications in Wireless Mesh Networks},
  Author                   = {Timo Lindhorst and Burkhard Weseloh and Edgar Nett},
  Booktitle                = {Proceedings of the 33rd IEEE Symposium on Reliable Distributed Systems},
  Year                     = {2014},
  note = {to appear},
}
Timo Lindhorst, Burkhard Weseloh, Edgar Nett
Maintaining Dependable Communication Service for Mobile Stations in Wireless Mesh Networks by Tracking Capacity Demands
Proceedings of the 28th IEEE International Parallel & Distributed Processing Symposium
Wireless Mesh Networks (WMNs) provide a promising foundation for a flexible
and reliable communication infrastructure in industrial environments. Meeting
the QoS demands of industrial applications, though, requires the deployment of
an admission control to avoid network overload. The presence of mobile
stations, however, causes dynamics within the network that severely impacts
the available capacity. For instance, if a communication route switches from
one to two hops, twice the resources are consumed due to self-interference. To
neither jeopardize QoS guarantees nor having to cancel present flows, our
dependable admission control scheme foresees and considers those dynamics
during resource reservation to handle station mobility.
We describe a highly dependable approach and further propose an estimation
method that improves network efficiency. The evaluation results show that our
novel approach allows for a dependable admission control even in presence of
mobile stations.
@InProceedings{Lindhorst14dpdns,
  Title                    = {Maintaining Dependable Communication Service for Mobile Stations in Wireless Mesh Networks by Tracking Capacity Demands},
  Author                   = {Timo Lindhorst and Burkhard Weseloh and Edgar Nett},
  Booktitle                = {Proceedings of the 28th IEEE International Parallel \& Distributed Processing Symposium},
  Year                     = {2014},
  Publisher                = {IEEE}
}

2013

Timo Lindhorst, Georg Lukas, Edgar Nett
Wireless Mesh Network Infrastructure for Industrial Applications - A Case Study of Tele-operated Mobile Robots
18th IEEE International Conference on Emerging Technologies and Factory Automation, September 10-13, 2013 Cagliary, Italy
The deployment of wireless communication networks in industrial facilities allows for increased flexibility and seamless integration of mobile participants. Time-critical control applications are generally realized with dedicated wireless sensor networks while common WLAN infrastructure networks allow high-throughput best-effort communication. To provide high-capacity communication as well as real-time service quality, we developed and implemented a Wireless Mesh Network (WMN) infrastructure for industrial applications. An example application that requires these properties is the video-based tele-operation of a mobile robot, which we present as case study in this work. It shows the applicability of our infrastructure as well as the necessity of its comprised components.
@INPROCEEDINGS{Lindhorst13,
  author = {Timo Lindhorst, Georg Lukas and Edgar Nett},
  title = {Wireless Mesh Network Infrastructure for Industrial Applications
        - A Case Study of Tele-operated Mobile Robots},
  booktitle = {18th IEEE International Conference on Emerging Technologies \& Factory
        Automation (ETFA)},
  year = {2013},
  file = {:Lindhorst13.pdf:PDF},
  owner = {timo},
  timestamp = {2013.09.18}
}
Frank Engelhardt, Timo Lindhorst, Edgar Nett
Tolerating Packet Losses in Wireless Mesh Networks
2013 IEEE 27th International Symposium on Parallel & Distributed Processing Workshops and PhD Forum, 20-24 May 2013, Boston (MA) USA
Wireless Mesh Networks (WMNs) provide a promising foundation for a flexible and reliable communication infrastructure in industrial environments. Meeting the QoS demands of real-time applications, though, requires the deployment of various advanced mechanisms. Compared to wired networks, applications face higher packet loss rates in wireless networks due to the inherent unreliability of wireless communication. Furthermore, if mobile stations are involved, links that fail due to node movement frequently cause packet losses. In this paper, we present an approach to tolerate those specific losses by locally recovering lost packets and transiently re-routing them over an alternative path. The evaluation in real-world experiments shows that we can completely prevent packet loss without significantly increasing the end-to-end latency. This allows the deployment of WMNs for real-time applications without explicitly considering the increased error-proneness of wireless communication and station mobility.

2011

Timo Lindhorst, Georg Lukas and Edgar Nett
Modeling Medium Utilization for Admission Control in Industrial Wireless Mesh Networks
In Proceedings of the 30th IEEE International Symposium on Reliable Distributed Systems, October 4-7, 2011. Madrid, Spain
@inproceedings{Lukas2011srds,
  author = {Georg Lukas and Timo Lindhorst and Edgar Nett},
  title = {Modeling Medium Utilization for Admission Control in Industrial Wireless Mesh Networks},
  booktitle = {IEEE International Symposium on Reliable Distributed Systems},
  publisher = {IEEE},
  year = {2011}
}
Frank Engelhardt, Timo Lindhorst and Ansgar Bredenfeld
Umsetzung eines Online-SLAM-Verfahrens auf der Roboterplattform VolksBot-Lab
In Virtuelle Instrumente in der Praxis 2011, Messtechnik Automatisierung Begleitband zum 16. VIP-Kongress, 24.-25. Oktober 2011, VDE Verlag.
Kurzfassung
Die Fähigkeit eines autonomen mobilen Roboters, während der Fahrt seine Umgebung zu kartieren, eröffnet ihm ein weites Spektrum von Anwendungen. In dieser Arbeit wird ein Online-SLAM-Verfahren präsentiert, das auf dem cRIO-Echtzeitsystem des Roboters VolksBot-Lab lauffähig ist und bei Indoor-Szenarien sowohl im Zeitverhalten als auch in der Kartenqualität sehr zuverlässige Ergebnisse liefert. Das Robotersystem kommt derzeit im Rahmen einer Lehrveranstaltung der Universität Magdeburg zum Einsatz.

Abstract
The ability of an autonomous mobile robot to explore and map its environment during operation opens a variety of applications. In this paper we present an online-SLAM solution, which runs on the cRIO realtime controller of the robot VolksBot-Lab. It provides reliable results in both its map quality and timing behavior concerning indoor scenarios. The robot is currently used within the scope of a student project at the University of Magdeburg.
@inproceedings{VIP2011,
  author = {Frank Engelhardt and Timo Lindhorst and Ansgar Bredenfeld},
  title = {{Umsetzung eines Online-SLAM-Verfahrens auf der Roboterplattform VolksBot-Lab}},
  booktitle = {{Virtuelle Instrumente in der Praxis 2011}},
  publisher = {VDE Verlag},
  year = {2011},
  month = {September}
}

2010

Timo Lindhorst, Georg Lukas, Edgar Nett, and Michael Mock
Data-mining-based Link Failure Detection for Wireless Mesh Networks
In Proceedings of the 29th IEEE International Symposium on Reliable Distributed Systems, 31 October - 4 November, 2010, New Delhi, India
Mobile robot applications operating in wireless environments require fast detection of link failures in order to enable fast repair. In previous work, we have shown that cross-layer failure detection can reduce failure detection latency significantly. In particular, we monitor the behavior of the WLAN MAC layer to predict failures on the link layer. In this paper, we investigate data mining techniques to determine which parameters, i.e., the events, or combination and timing of events, occurring on the MAC layer most probably lead to link failures. Our results show, that the parameters revealed with the data mining approach produce similar or even more accurate failure predictions than achieved so far.
@inproceedings{Lindhorst2010-srds,
  author = {Timo Lindhorst and Georg Lukas and Edgar Nett and Michael Mock},
  title = {Data-mining-based Link Failure Detection for Wireless Mesh Networks},
  booktitle = {IEEE International Symposium on Reliable Distributed Systems},
  publisher = {IEEE},
  year = {2010},
  month = {November}
}
Ansgar Bredenfeld, Manuela Kanneberg, Timo Lindhorst, and Edgar Nett
Im Praxistest
In A&D Vorsprung Automation, November 2010, München, pp. 120-122
Die Universität Magdeburg bietet Informatikstudenten die Möglichkeit, in Software-Projekten die Theorie in die Praxis umzusetzen. Das Projekt Teamrobotik vermittelte so anhand von mobilen VolksBot-RT3-Robotern unter anderem Erfahrungen im Bereich Bildverarbeitung, Navigation und Hinderniserkennung.
@article{praxistestAD,
  author = {Ansgar Bredenfeld and Timo Lindhorst and Manuela Kanneberg and Edgar Nett},
  title = {Im Praxistest},
  journal = {A\&D Vorsprung Automation},
  year = {2010},
  volume = {November},
  pages = {120-122}
}
Timo Lindhorst, Georg Lukas, and Edgar Nett
Modeling Fast Link Failure Detection for Dependable Wireless Mesh Networks
In Proceedings of the 9th IEEE International Symposium on Network Computing and Applications, 15 - 17 July, 2010, Cambridge, MA, USA
Wireless Mesh Networks (WMN) provide a flexible and inexpensive way to expand network applications to mobile entities. However, high communication reliability demands can not be met by regular WMNs due to mobility and inherent properties of wireless communication. Failing links are common events which impose a major challenge for providing a dependable communication service. By the use of suitable cross-layer models, we provide a timely detection of failed links without compromising the network stability. It is shown that the packet loss caused by a link failure can be reduced from a time-dependent value to at most four consecutive packets. For a typical control application this means an improvement by a factor of 100. In addition to an empirical evaluation we demonstrate the applicability of the mechanism by utilizing it in a real-world WMN to allow the tele-operation of a mobile robot.
@inproceedings{Lindhorst2010,
  author = {Timo Lindhorst and Georg Lukas and Edgar Nett},
  title = {Modeling Fast Link Failure Detection for Dependable Wireless Mesh Networks},
  booktitle = {IEEE International Symposium on Network Computing and Applications},
  publisher = {IEEE},
  year = {2010},
  month = {July},
  doi = {http://doi.ieeecomputersociety.org/10.1109/NCA.2010.13}
}
Timo Lindhorst, Manuela Kanneberg, Edgar Nett and Ansgar Bredenfeld
VolksBot mit CompactRIO und LabVIEW - Erfahrungen aus der Lehrveranstaltung "Teamrobotik"
15. Technologie- und Anwenderkongress VIP 2010 - „Virtuelle Instrumente in der Praxis“ ; 27.-28. Oktober 2010, Fürstenfeld bei München, Germany
@inproceedings{VIP2010,
  author = {Ansgar Bredenfeld and Timo Lindhorst and Manuela Kanneberg and Edgar Nett},
  title = {VolksBot mit CompactRIO und LabVIEW - Erfahrungen aus der Lehrveranstaltungsreihe "Teamrobotik"},
  booktitle = {Virtuelle Instrumente in der Praxis 2010},
  publisher = {VDE Verlag},
  year = {2010},
  month = {October}
}

2009

Timo Lindhorst
Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken
In Informatik aktuell: Software-intensive verteilte Echtzeitsysteme - Echtzeit 2009, Wolfgang A. Halang, Peter Holleczek (Hrsg.);
Fachtagung des GI/GMA - Fachausschusses Echtzeitsysteme, Boppard, November 19-20, 2009;
ISBN 978-3-642-04782-4, Springer-Verlag
Drahtlose Mesh-Netzwerke (WMNs) bilden aufgrund ihrer Selbstorganisation ein flexibles Kommunikationssystem. Bei der Erkennung einzelner Verbindungsausfälle, die bei der Integration mobiler Teilnehmer unvermeidbar sind, ist bei aktuellen Routingprotokollen die Kommunikation jedoch für mehrere Sekunden unterbrochen. In dieser Arbeit wird gezeigt, wie durch Nutzung von Informationen aus der MAC-Schicht ein Ausfall frühzeitig erkannt und dadurch die Anzahl der Paketverluste von mehreren Hundert auf maximal vier reduziert werden kann. Hierdurch wird die Zuverlässigkeit und Verfügbarkeit von WMNs erhöht und ihr Einsatz für Echtzeit-Anwendungen ermöglicht.
@inproceedings{cite:xalf-boppard09,
  author = {Timo Lindhorst},
  title = {Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken},
  booktitle = {Software-intensive verteilte Echtzeitsysteme - Echtzeit 2009},
  publisher = {Springer},
  year = {2009},
  month = {November},
  pages = {67 ff.}
}
Timo Lindhorst
Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken
Diplomarbeit, Otto-von-Guericke-Universität Magdeburg, Februar, 2009.
@mastersthesis{xalf-thesis,
  author = {Lindhorst, Timo},
  title = {Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken},
  school = {Otto-von-Guericke-Universität Magdeburg},
  year = {2009},
  month = {Februar},
  type = {Diplomarbeit}
}

2008

Timo Lindhorst, André Herms, Michael Schulze
Einsatz einer Echtzeit-Publish/Subscribe-Kommunikation für die Teleoperation mobiler Roboter
In Informatik aktuell: Aktuelle Anwendungen in Technik und Wirtschaft - Echtzeit 2008, Wolfgang A. Halang, Peter Holleczek (Hrsg.);
Fachtagung des GI/GMA - Fachausschusses Echtzeitsysteme, Boppard, November 27-28, 2008;
ISBN 978-3-540-85323-7, Springer-Verlag
In der Telerobotik werden mobile Roboter über ein Kommunikationsnetz durch einen Operator ferngesteuert. Um interaktiv zu operieren, müssen Daten in beide Richtungen in Echtzeit kommuniziert werden. Zusätzlich ist eine hohe Ausfallsicherheit des Systems zu gewährleisten. Diese Arbeit beschreibt die Umsetzung eines solchen Szenarios unter Verwendung einer Echtzeit-Publish/Subscribe-Kommunikation. Ein drahtloses Mesh-Netzwerk erfüllt durch redundante Verbindungen die Anforderungen an die Kommunikation. Eine Publish/Subscribe-Middleware ermöglicht eine inhaltsbasierte Kommunikation und erlaubt dadurch eine hohe Flexibilität der Teilnehmer. Durch die modulare Software-Architektur der Applikationen entsteht ein verteiltes System, in dem mobile Roboter durch netzwerktransparente Kommunikation gesteuert werden.