TY - CONF AU - Hinnenthal, Kristian AU - Scheideler, Christian AU - Struijs, Martijn ID - 13652 T2 - 33rd International Symposium on Distributed Computing (DISC 2019) TI - Fast Distributed Algorithms for LP-Type Problems of Low Dimension ER - TY - CONF AU - Augustine, John AU - Hinnenthal, Kristian AU - Kuhn, Fabian AU - Scheideler, Christian AU - Schneider, Philipp ED - Chawla, Shuchi ID - 27051 T2 - Proceedings of the 2020 ACM-SIAM Symposium on Discrete Algorithms, SODA 2020, Salt Lake City, UT, USA, January 5-8, 2020 TI - Shortest Paths in a Hybrid Network Model ER - TY - JOUR AU - Gmyr, Robert AU - Hinnenthal, Kristian AU - Kostitsyna, Irina AU - Kuhn, Fabian AU - Rudolph, Dorian AU - Scheideler, Christian AU - Strothmann, Thim ID - 17808 IS - 2 JF - Nat. Comput. TI - Forming tile shapes with simple robots VL - 19 ER - TY - CONF AB - We consider the problem of computing shortest paths in \emph{hybrid networks}, in which nodes can make use of different communication modes. For example, mobile phones may use ad-hoc connections via Bluetooth or Wi-Fi in addition to the cellular network to solve tasks more efficiently. Like in this case, the different communication modes may differ considerably in range, bandwidth, and flexibility. We build upon the model of Augustine et al. [SODA '20], which captures these differences by a \emph{local} and a \emph{global} mode. Specifically, the local edges model a fixed communication network in which $O(1)$ messages of size $O(\log n)$ can be sent over every edge in each synchronous round. The global edges form a clique, but nodes are only allowed to send and receive a total of at most $O(\log n)$ messages over global edges, which restricts the nodes to use these edges only very sparsely. We demonstrate the power of hybrid networks by presenting algorithms to compute Single-Source Shortest Paths and the diameter very efficiently in \emph{sparse graphs}. Specifically, we present exact $O(\log n)$ time algorithms for cactus graphs (i.e., graphs in which each edge is contained in at most one cycle), and $3$-approximations for graphs that have at most $n + O(n^{1/3})$ edges and arboricity $O(\log n)$. For these graph classes, our algorithms provide exponentially faster solutions than the best known algorithms for general graphs in this model. Beyond shortest paths, we also provide a variety of useful tools and techniques for hybrid networks, which may be of independent interest. AU - Feldmann, Michael AU - Hinnenthal, Kristian AU - Scheideler, Christian ID - 20755 T2 - Proceedings of the 24th International Conference on Principles of Distributed Systems (OPODIS) TI - Fast Hybrid Network Algorithms for Shortest Paths in Sparse Graphs ER - TY - JOUR AB - The maintenance of efficient and robust overlay networks is one of the most fundamental and reoccurring themes in networking. This paper presents a survey of state-of-the-art algorithms to design and repair overlay networks in a distributed manner. In particular, we discuss basic algorithmic primitives to preserve connectivity, review algorithms for the fundamental problem of graph linearization, and then survey self-stabilizing algorithms for metric and scalable topologies. We also identify open problems and avenues for future research. AU - Feldmann, Michael AU - Scheideler, Christian AU - Schmid, Stefan ID - 16902 JF - ACM Computing Surveys TI - Survey on Algorithms for Self-Stabilizing Overlay Networks ER - TY - CONF AB - We consider the clock synchronization problem in the (discrete) beeping model: Given a network of $n$ nodes with each node having a clock value $\delta(v) \in \{0,\ldots T-1\}$, the goal is to synchronize the clock values of all nodes such that they have the same value in any round. As is standard in clock synchronization, we assume \emph{arbitrary activations} for all nodes, i.e., the nodes start their protocol at an arbitrary round (not limited to $\{0,\ldots,T-1\}$). We give an asymptotically optimal algorithm that runs in $4D + \Bigl\lfloor \frac{D}{\lfloor T/4 \rfloor} \Bigr \rfloor \cdot (T \mod 4) = O(D)$ rounds, where $D$ is the diameter of the network. Once all nodes are in sync, they beep at the same round every $T$ rounds. The algorithm drastically improves on the $O(T D)$-bound of \cite{firefly_sync} (where $T$ is required to be at least $4n$, so the bound is no better than $O(nD)$). Our algorithm is very simple as nodes only have to maintain $3$ bits in addition to the $\lceil \log T \rceil$ bits needed to maintain the clock. Furthermore we investigate the complexity of \emph{self-stabilizing} solutions for the clock synchronization problem: We first show lower bounds of $\Omega(\max\{T,n\})$ rounds on the runtime and $\Omega(\log(\max\{T,n\}))$ bits of memory required for any such protocol. Afterwards we present a protocol that runs in $O(\max\{T,n\})$ rounds using at most $O(\log(\max\{T,n\}))$ bits at each node, which is asymptotically optimal with regards to both, runtime and memory requirements. AU - Feldmann, Michael AU - Khazraei, Ardalan AU - Scheideler, Christian ID - 16903 T2 - Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - Time- and Space-Optimal Discrete Clock Synchronization in the Beeping Model ER - TY - CONF AU - Castenow, Jannik AU - Kolb, Christina AU - Scheideler, Christian ID - 15169 T2 - Proceedings of the 21st International Conference on Distributed Computing and Networking (ICDCN) TI - A Bounding Box Overlay for Competitive Routing in Hybrid Communication Networks ER - TY - CONF AU - Daymude, Joshua J. AU - Gmyr, Robert AU - Hinnenthal, Kristian AU - Kostitsyna, Irina AU - Scheideler, Christian AU - Richa, Andréa W. ID - 16346 SN - 9781450377515 T2 - Proceedings of the 21st International Conference on Distributed Computing and Networking TI - Convex Hull Formation for Programmable Matter ER - TY - CONF AU - Dolev, Shlomi AU - Prasadh Narayanan, Ram AU - Scheideler, Christian AU - Schindelhauer, Christian ED - Galluccio, Laura ED - Mitra, Urbashi ED - Magarini, Maurizio ED - Abada, Sergi ED - Taynnan Barros, Michael ED - Krishnaswamy, Bhuvana ID - 25105 T2 - NANOCOM '21: The Eighth Annual ACM International Conference on Nanoscale Computing and Communication, Virtual Event, Italy, September 7 - 9, 2021 TI - Logarithmic Time MIMO Based Self-Stabilizing Clock Synchronization ER - TY - CONF AU - Feldmann, Michael AU - Padalkin, Andreas AU - Scheideler, Christian AU - Dolev, Shlomi ED - Johnen, Colette ED - Michael Schiller, Elad ED - Schmid, Stefan ID - 28917 T2 - Stabilization, Safety, and Security of Distributed Systems - 23rd International Symposium, (SSS) 2021, Virtual Event, November 17-20, 2021, Proceedings TI - Coordinating Amoebots via Reconfigurable Circuits VL - 13046 ER - TY - CONF AU - Dolev, Shlomi AU - Prasadh Narayanan, Ram AU - Scheideler, Christian AU - Schindelhauer, Christian ED - Galluccio, Laura ED - Mitra, Urbashi ED - Magarini, Maurizio ED - Abada, Sergi ED - Taynnan Barros, Michael ED - Krishnaswamy, Bhuvana ID - 27048 T2 - NANOCOM '21: The Eighth Annual ACM International Conference on Nanoscale Computing and Communication, Virtual Event, Italy, September 7 - 9, 2021 TI - Logarithmic Time MIMO Based Self-Stabilizing Clock Synchronization ER - TY - CONF AU - J. Daymude, Joshua AU - W. Richa, Andrea AU - Scheideler, Christian ED - Gilbert, Seth ID - 27050 T2 - 35th International Symposium on Distributed Computing, DISC 2021, October 4-8, 2021, Freiburg, Germany (Virtual Conference) TI - The Canonical Amoebot Model: Algorithms and Concurrency Control VL - 209 ER - TY - CONF AB - We show how to construct an overlay network of constant degree and diameter $O(\log n)$ in time $O(\log n)$ starting from an arbitrary weakly connected graph. We assume a synchronous communication network in which nodes can send messages to nodes they know the identifier of and establish new connections by sending node identifiers. If the initial network's graph is weakly connected and has constant degree, then our algorithm constructs the desired topology with each node sending and receiving only $O(\log n)$ messages in each round in time $O(\log n)$, w.h.p., which beats the currently best $O(\log^{3/2} n)$ time algorithm of [Götte et al., SIROCCO'19]. Since the problem cannot be solved faster than by using pointer jumping for $O(\log n)$ rounds (which would even require each node to communicate $\Omega(n)$ bits), our algorithm is asymptotically optimal. We achieve this speedup by using short random walks to repeatedly establish random connections between the nodes that quickly reduce the conductance of the graph using an observation of [Kwok and Lau, APPROX'14]. Additionally, we show how our algorithm can be used to efficiently solve graph problems in \emph{hybrid networks} [Augustine et al., SODA'20]. Motivated by the idea that nodes possess two different modes of communication, we assume that communication of the \emph{initial} edges is unrestricted. In contrast, only polylogarithmically many messages can be communicated over edges that have been established throughout an algorithm's execution. For an (undirected) graph $G$ with arbitrary degree, we show how to compute connected components, a spanning tree, and biconnected components in time $O(\log n)$, w.h.p. Furthermore, we show how to compute an MIS in time $O(\log d + \log \log n)$, w.h.p., where $d$ is the initial degree of $G$. AU - Götte, Thorsten AU - Hinnenthal, Kristian AU - Scheideler, Christian AU - Werthmann, Julian ED - Censor-Hillel, Keren ID - 22283 T2 - Proc. of the 40th ACM Symposium on Principles of Distributed Computing (PODC '21) TI - Time-Optimal Construction of Overlays ER - TY - CONF AU - Coy, Sam AU - Czumaj, Artur AU - Feldmann, Michael AU - Hinnenthal, Kristian AU - Kuhn, Fabian AU - Scheideler, Christian AU - Schneider, Philipp AU - Struijs, Martijn ED - Bramas, Quentin ED - Gramoli, Vincent ED - Milani, Alessia ID - 30217 T2 - 25th International Conference on Principles of Distributed Systems, OPODIS 2021, December 13-15, 2021, Strasbourg, France TI - Near-Shortest Path Routing in Hybrid Communication Networks VL - 217 ER - TY - CHAP AU - Götte, Thorsten AU - Kolb, Christina AU - Scheideler, Christian AU - Werthmann, Julian ID - 26888 SN - 0302-9743 T2 - Algorithms for Sensor Systems (ALGOSENSORS '21) TI - Beep-And-Sleep: Message and Energy Efficient Set Cover ER - TY - JOUR AU - Feldmann, Michael AU - Padalkin, Andreas AU - Scheideler, Christian AU - Dolev, Shlomi ID - 31060 IS - 4 JF - J. Comput. Biol. TI - Coordinating Amoebots via Reconfigurable Circuits VL - 29 ER - TY - CONF AU - Padalkin, Andreas AU - Scheideler, Christian AU - Warner, Daniel ED - Ouldridge, Thomas E. ED - Wickham, Shelley F. J. ID - 32602 SN - 1868-8969 T2 - 28th International Conference on DNA Computing and Molecular Programming (DNA 28) TI - The Structural Power of Reconfigurable Circuits in the Amoebot Model VL - 238 ER - TY - CONF AU - Kostitsyna, Irina AU - Scheideler, Christian AU - Warner, Daniel ED - Ouldridge, Thomas E. ED - Wickham, Shelley F. J. ID - 32603 SN - 1868-8969 T2 - 28th International Conference on DNA Computing and Molecular Programming (DNA 28) TI - Fault-Tolerant Shape Formation in the Amoebot Model VL - 238 ER - TY - CONF AU - Daymude, Joshua J. AU - Richa, Andréa W. AU - Scheideler, Christian ED - Aspnes, James ED - Michail, Othon ID - 33230 T2 - 1st Symposium on Algorithmic Foundations of Dynamic Networks, SAND 2022, March 28-30, 2022, Virtual Conference TI - Local Mutual Exclusion for Dynamic, Anonymous, Bounded Memory Message Passing Systems VL - 221 ER - TY - CONF AU - Götte, Thorsten AU - Scheideler, Christian ED - Agrawal, Kunal ED - Lee, I-Ting Angelina ID - 33240 T2 - SPAA ’22: 34th ACM Symposium on Parallelism in Algorithms and Architectures, Philadelphia, PA, USA, July 11 - 14, 2022 TI - Brief Announcement: The (Limited) Power of Multiple Identities: Asynchronous Byzantine Reliable Broadcast with Improved Resilience through Collusion ER -