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Im Juni 2018 sprach der britische Journalist und Redakteur Gary Younge vom „Guardian“ mit Interessierten unter anderem über Waffengewalt in Amerika. Bildinformationen anzeigen
Bei wissenschaftlichen Kolloquien steht der direkte Austausch im Fokus. Bildinformationen anzeigen
An der Universität Paderborn finden in allen Bereichen und zu vielfältigen Themen Kolloquien statt. Bildinformationen anzeigen
Weitere Informationen zu aktuellen Kolloquien und Terminen gibt es im Veranstaltungskalender auf der Webseite der Universität Paderborn. Bildinformationen anzeigen

Wissenschaftliches Kolloquium

Im Juni 2018 sprach der britische Journalist und Redakteur Gary Younge vom „Guardian“ mit Interessierten unter anderem über Waffengewalt in Amerika.

Foto: Universität Paderborn, Adelheid Rutenburges

Wissenschaftliches Kolloquium

Bei wissenschaftlichen Kolloquien steht der direkte Austausch im Fokus.

Foto: Universität Paderborn, Adelheid Rutenburges

Wissenschaftliches Kolloquium

An der Universität Paderborn finden in allen Bereichen und zu vielfältigen Themen Kolloquien statt.

Foto: Universität Paderborn, Adelheid Rutenburges

Wissenschaftliches Kolloquium

Weitere Informationen zu aktuellen Kolloquien und Terminen gibt es im Veranstaltungskalender auf der Webseite der Universität Paderborn.

Foto: Universität Paderborn, Adelheid Rutenburges

Michael Feldmann

Kontakt
Profil
Publikationen
 Michael Feldmann

Theorie verteilter Systeme

Wissenschaftlicher Mitarbeiter

Telefon:
+49 5251 60-6722
Fax:
+49 5251 60-6697
Büro:
F2.403
Besucher:
Fürstenallee 11
33102 Paderborn
Postanschrift:
Warburger Str. 100
33098 Paderborn

Sonderforschungsbereich 901

Wissenschaftlicher Mitarbeiter

Lehre
  • WS 10/11: Übungen für "Technische Informatik für Ingenieure"
  • WS 11/12: Übungen für "Technische Informatik für Ingenieure"
  • WS 12/13: Übungen für "Grundlagen der Programmierung für Maschinenbauer"
  • WS 13/14: Übungen für "Grundlagen der Programmierung für Maschinenbauer"
  • WS 14/15: Übungen für "Grundlagen der Programmierung für Maschinenbauer"
  • SS 2016: Übungen für "Datenstrukturen und Algorithmen"
  • WS16/17: Übungen für "Grundlagen der Programmierung I"
  • WS17/18: Übungen für "Programmierung"

Liste im Research Information System öffnen

2018

Self-stabilizing Overlays for high-dimensional Monotonic Searchability

M. Feldmann, C. Kolb, C. Scheideler, in: Proceedings of the 20th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS), Springer, Cham, 2018, pp. 16-31

We extend the concept of monotonic searchability~\cite{DBLP:conf/opodis/ScheidelerSS15}~\cite{DBLP:conf/wdag/ScheidelerSS16} for self-stabilizing systems from one to multiple dimensions. A system is self-stabilizing if it can recover to a legitimate state from any initial illegal state. These kind of systems are most often used in distributed applications. Monotonic searchability provides guarantees when searching for nodes while the recovery process is going on. More precisely, if a search request started at some node $u$ succeeds in reaching its destination $v$, then all future search requests from $u$ to $v$ succeed as well. Although there already exists a self-stabilizing protocol for a two-dimensional topology~\cite{DBLP:journals/tcs/JacobRSS12} and an universal approach for monotonic searchability~\cite{DBLP:conf/wdag/ScheidelerSS16}, it is not clear how both of these concepts fit together effectively. The latter concept even comes with some restrictive assumptions on messages, which is not the case for our protocol. We propose a simple novel protocol for a self-stabilizing two-dimensional quadtree that satisfies monotonic searchability. Our protocol can easily be extended to higher dimensions and offers routing in $\mathcal O(\log n)$ hops for any search request.


Self-Stabilizing Supervised Publish-Subscribe Systems

M. Feldmann, C. Kolb, C. Scheideler, T.F. Strothmann, in: Proceedings of the 32nd IEEE International Parallel & Distributed Processing Symposium (IPDPS), IEEE, 2018

In this paper we present two major results: First, we introduce the first self-stabilizing version of a supervised overlay network (as introduced in~\cite{DBLP:conf/ispan/KothapalliS05}) by presenting a self-stabilizing supervised skip ring. Secondly, we show how to use the self-stabilizing supervised skip ring to construct an efficient self-stabilizing publish-subscribe system. That is, in addition to stabilizing the overlay network, every subscriber of a topic will eventually know all of the publications that have been issued so far for that topic. The communication work needed to processes a subscribe or unsubscribe operation is just a constant in a legitimate state, and the communication work of checking whether the system is still in a legitimate state is just a constant on expectation for the supervisor as well as any process in the system.


Skueue: A Scalable and Sequentially Consistent Distributed Queue

M. Feldmann, C. Scheideler, A. Setzer, in: Proceedings of the 32nd IEEE International Parallel & Distributed Processing Symposium (IPDPS), IEEE, 2018

We propose a distributed protocol for a queue, called Skueue, which spreads its data fairly onto multiple processes, avoiding bottlenecks in high throughput scenarios. Skueuecan be used in highly dynamic environments, through the addition of join and leave requests to the standard queue operations enqueue and dequeue. Furthermore Skueue satisfies sequential consistency in the asynchronous message passing model. Scalability is achieved by aggregating multiple requests to a batch, which can then be processed in a distributed fashion without hurting the queue semantics. Operations in Skueue need a logarithmic number of rounds w.h.p. until they are processed, even under a high rate of incoming requests.


2017

A Self-Stabilizing General De Bruijn Graph

M. Feldmann, C. Scheideler, in: Proceedings of the 19th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS), Springer, Cham, 2017, pp. 250-264

Searching for other participants is one of the most important operations in a distributed system.We are interested in topologies in which it is possible to route a packet in a fixed number of hops until it arrives at its destination.Given a constant $d$, this paper introduces a new self-stabilizing protocol for the $q$-ary $d$-dimensional de Bruijn graph ($q = \sqrt[d]{n}$) that is able to route any search request in at most $d$ hops w.h.p., while significantly lowering the node degree compared to the clique: We require nodes to have a degree of $\mathcal O(\sqrt[d]{n})$, which is asymptotically optimal for a fixed diameter $d$.The protocol keeps the expected amount of edge redirections per node in $\mathcal O(\sqrt[d]{n})$, when the number of nodes in the system increases by factor $2^d$.The number of messages that are periodically sent out by nodes is constant.


2015


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