@inproceedings{10586,
abstract = {We consider the problem of transforming a given graph G_s into a desired graph G_t by applying a minimum number of primitives from a particular set of local graph transformation primitives. These primitives are local in the sense that each node can apply them based on local knowledge and by affecting only its 1-neighborhood. Although the specific set of primitives we consider makes it possible to transform any (weakly) connected graph into any other (weakly) connected graph consisting of the same nodes, they cannot disconnect the graph or introduce new nodes into the graph, making them ideal in the context of supervised overlay network transformations. We prove that computing a minimum sequence of primitive applications (even centralized) for arbitrary G_s and G_t is NP-hard, which we conjecture to hold for any set of local graph transformation primitives satisfying the aforementioned properties. On the other hand, we show that this problem admits a polynomial time algorithm with a constant approximation ratio.},
author = {Scheideler, Christian and Setzer, Alexander},
booktitle = {Proceedings of the 46th International Colloquium on Automata, Languages, and Programming},
keyword = {Graphs transformations, NP-hardness, approximation algorithms},
location = {Patras, Greece},
pages = {150:1----150:14},
publisher = {Dagstuhl Publishing},
title = {{On the Complexity of Local Graph Transformations}},
doi = {10.4230/LIPICS.ICALP.2019.150},
volume = {132},
year = {2019},
}
@inproceedings{7636,
abstract = {Self-stabilizing overlay networks have the advantage of being able to recover from illegal states and faults.
However, the majority of these networks cannot give any guarantees on their functionality while the recovery process is going on.
We are especially interested in searchability, i.e., the functionality that search messages for a specific node are answered successfully if a node exists in the network.
In this paper we investigate overlay networks that ensure the maintenance of monotonic searchability while the self-stabilization is going on.
More precisely, once a search message from node u to another node v is successfully delivered, all future search messages from u to v succeed as well.
We extend the existing research by focusing on skip graphs and present a solution for two scenarios: (i) the goal topology is a super graph of the perfect skip graph and (ii) the goal topology is exactly the perfect skip graph.
},
author = {Luo, Linghui and Scheideler, Christian and Strothmann, Thim Frederik},
booktitle = {Proceedings of the 2019 IEEE 33rd International Parallel and Distributed Processing Symposium (IPDPS '19)},
location = {Rio de Janeiro, Brazil},
title = {{MultiSkipGraph: A Self-stabilizing Overlay Network that Maintains Monotonic Searchability}},
year = {2019},
}
@inproceedings{13182,
abstract = {We consider congestion control in peer-to-peer distributed systems.
The problem can be reduced to the following scenario: Consider a set $V$ of $n$ peers (called \emph{clients} in this paper) that want to send messages to a fixed common peer (called \emph{server} in this paper).
We assume that each client $v \in V$ sends a message with probability $p(v) \in [0,1)$ and the server has a capacity of $\sigma \in \mathbb{N}$, i.e., it can recieve at most $\sigma$ messages per round and excess messages are dropped.
The server can modify these probabilities when clients send messages.
Ideally, we wish to converge to a state with $\sum p(v) = \sigma$ and $p(v) = p(w)$ for all $v,w \in V$.
We propose a \emph{loosely} self-stabilizing protocol with a slightly relaxed legitimate state.
Our protocol lets the system converge from \emph{any} initial state to a state where $\sum p(v) \in \left[\sigma \pm \epsilon\right]$ and $|p(v)-p(w)| \in O(\frac{1}{n})$.
This property is then maintained for $\Omega(n^{\mathfrak{c}})$ rounds in expectation.
In particular, the initial client probabilities and server variables are not necessarily well-defined, i.e., they may have arbitrary values.
Our protocol uses only $O(W + \log n)$ bits of memory where $W$ is length of node identifiers, making it very lightweight.
Finally we state a lower bound on the convergence time an see that our protocol performs asymptotically optimal (up to some polylogarithmic factor).
},
author = {Feldmann, Michael and Götte, Thorsten and Scheideler, Christian},
booktitle = {Proceedings of the 21st International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)},
pages = {149--164},
publisher = {Springer, Cham},
title = {{A Loosely Self-stabilizing Protocol for Randomized Congestion Control with Logarithmic Memory}},
doi = {https://doi.org/10.1007/978-3-030-34992-9_13},
year = {2019},
}
@inproceedings{12944,
author = {Götte, Thorsten and Hinnenthal, Kristian and Scheideler, Christian},
booktitle = {Structural Information and Communication Complexity},
title = {{Faster Construction of Overlay Networks}},
doi = {10.1007/978-3-030-24922-9_18},
year = {2019},
}
@inproceedings{14539,
author = {Castenow, Jannik and Kolb, Christina and Scheideler, Christian},
booktitle = {Proceedings of the 26th International Colloquium on Structural Information and Communication Complexity (SIROCCO)},
location = {L'Aquila, Italy},
pages = {345--348},
title = {{A Bounding Box Overlay for Competitive Routing in Hybrid Communication Networks}},
doi = {10.1007/978-3-030-24922-9\_26},
year = {2019},
}
@inproceedings{8534,
abstract = {We propose two protocols for distributed priority queues (denoted by 'heap' for simplicity in this paper) called SKEAP and SEAP. SKEAP realizes a distributed heap for a constant amount of priorities and SEAP one for an arbitrary amount. Both protocols build on an overlay, which induces an aggregation tree on which heap operations are aggregated in batches, ensuring that our protocols scale even for a high rate of incoming requests. As part of SEAP we provide a novel distributed protocol for the k-selection problem that runs in time O(log n) w.h.p. SKEAP guarantees sequential consistency for its heap operations, while SEAP guarantees serializability. SKEAP and SEAP provide logarithmic runtimes w.h.p. on all their operations.
SKEAP and SEAP provide logarithmic runtimes w.h.p. on all their operations with SEAP having to use only O(log n) bit messages.},
author = {Feldmann, Michael and Scheideler, Christian},
booktitle = {Proceedings of the 31st ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)},
pages = {287----296},
publisher = {ACM},
title = {{Skeap & Seap: Scalable Distributed Priority Queues for Constant and Arbitrary Priorities}},
doi = {10.1145/3323165.3323193},
year = {2019},
}
@inbook{9599,
author = {Daymude, Joshua J. and Hinnenthal, Kristian and Richa, Andréa W. and Scheideler, Christian},
booktitle = {Distributed Computing by Mobile Entities, Current Research in Moving and Computing.},
pages = {615--681},
publisher = {Springer, Cham},
title = {{Computing by Programmable Particles}},
doi = {https://doi.org/10.1007/978-3-030-11072-7_22},
year = {2019},
}
@inproceedings{3422,
abstract = {We study the consensus problem in a synchronous distributed system of n nodes under an adaptive adversary that has a slightly outdated view of the system and can block all incoming and outgoing communication of a constant fraction of the nodes in each round. Motivated by a result of Ben-Or and Bar-Joseph (1998), showing that any consensus algorithm that is resilient against a linear number of crash faults requires $\tilde \Omega(\sqrt n)$ rounds in an n-node network against an adaptive adversary, we consider a late adaptive adversary, who has full knowledge of the network state at the beginning of the previous round and unlimited computational power, but is oblivious to the current state of the nodes.
Our main contributions are randomized distributed algorithms that achieve consensus with high probability among all except a small constant fraction of the nodes (i.e., "almost-everywhere'') against a late adaptive adversary who can block up to ε n$ nodes in each round, for a small constant ε >0$. Our first protocol achieves binary almost-everywhere consensus and also guarantees a decision on the majority input value, thus ensuring plurality consensus. We also present an algorithm that achieves the same time complexity for multi-value consensus. Both of our algorithms succeed in $O(log n)$ rounds with high probability, thus showing an exponential gap to the $\tilde\Omega(\sqrt n)$ lower bound of Ben-Or and Bar-Joseph for strongly adaptive crash-failure adversaries, which can be strengthened to $\Omega(n)$ when allowing the adversary to block nodes instead of permanently crashing them. Our algorithms are scalable to large systems as each node contacts only an (amortized) constant number of peers in each communication round. We show that our algorithms are optimal up to constant (resp.\ sub-logarithmic) factors by proving that every almost-everywhere consensus protocol takes $\Omega(log_d n)$ rounds in the worst case, where d is an upper bound on the number of communication requests initiated per node in each round. We complement our theoretical results with an experimental evaluation of the binary almost-everywhere consensus protocol revealing a short convergence time even against an adversary blocking a large fraction of nodes.},
author = {Robinson, Peter and Scheideler, Christian and Setzer, Alexander},
booktitle = {Proceedings of the 30th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)},
isbn = {978-1-4503-5799-9/18/07},
keyword = {distributed consensus, randomized algorithm, adaptive adversary, complexity lower bound},
location = {Wien},
title = {{Breaking the $\tilde\Omega(\sqrt{n})$ Barrier: Fast Consensus under a Late Adversary}},
doi = {10.1145/3210377.3210399},
year = {2018},
}
@inproceedings{5764,
author = {Gmyr, Robert and Hinnenthal, Kristian and Kostitsyna, Irina and Kuhn, Fabian and Rudolph, Dorian and Scheideler, Christian and Strothmann, Thim Frederik},
booktitle = {Proceedings of the 24th International Conference on DNA Computing and Molecular Programming},
pages = {122--138},
publisher = {Springer International Publishing},
title = {{Forming Tile Shapes with Simple Robots}},
doi = {10.1007/978-3-030-00030-1_8},
year = {2018},
}
@inproceedings{5985,
author = {Scheideler, Christian},
booktitle = {Proceedings of the 2018 Workshop on Theory and Practice for Integrated Cloud, Fog and Edge Computing Paradigms, TOPIC@PODC 2018, Egham, United Kingdom, July 27, 2018},
pages = {1--2},
title = {{Relays: Towards a Link Layer for Robust and Secure Fog Computing}},
doi = {10.1145/3229774.3229781},
year = {2018},
}