@article{1858, author = {{Jacob, Riko and W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Täubig, Hanjo}}, journal = {{J. ACM}}, number = {{6}}, pages = {{36:1----36:26}}, title = {{{SKIP*: A Self-Stabilizing Skip Graph}}}, doi = {{10.1145/2629695}}, year = {{2014}}, } @inproceedings{1863, author = {{Derakhshandeh, Zahra and Dolev, Shlomi and Gmyr, Robert and W. Richa, Andrea and Scheideler, Christian and Strothmann, Thim Frederik}}, booktitle = {{26th ACM Symposium on Parallelism in Algorithms and Architectures, SPAA'14, Prague, Czech Republic - June 23 - 25, 2014}}, isbn = {{978-1-4503-2821-0}}, pages = {{220----222}}, publisher = {{ACM}}, title = {{{Brief announcement: amoebot - a new model for programmable matter}}}, doi = {{10.1145/2612669.2612712}}, year = {{2014}}, } @inproceedings{446, abstract = {{This paper considers the problem of how to efficiently share a wireless medium which is subject to harsh external interference or even jamming. While this problem has already been studied intensively for simplistic single-hop or unit disk graph models, we make a leap forward and study MAC protocols for the SINR interference model (a.k.a. the physical model). We make two contributions. First, we introduce a new adversarial SINR model which captures a wide range of interference phenomena. Concretely, we consider a powerful, adaptive adversary which can jam nodes at arbitrary times and which is only limited by some energy budget. The second contribution of this paper is a distributed MAC protocol which provably achieves a constant competitive throughput in this environment: we show that, with high probability, the protocol ensures that a constant fraction of the non-blocked time periods is used for successful transmissions.}}, author = {{Ogierman, Adrian and Richa, Andrea W. and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{Proceedings of the 33rd Annual IEEE International Conference on Computer Communications (INFOCOM)}}, pages = {{2751----2759}}, title = {{{Competitive MAC under adversarial SINR}}}, doi = {{10.1109/INFOCOM.2014.6848224}}, year = {{2014}}, } @inproceedings{459, abstract = {{In this survey article, we discuss two algorithmic research areas that emerge from problems that arise when resources are offered in the cloud. The first area, online leasing, captures problems arising from the fact that resources in the cloud are not bought, but leased by cloud vendors. The second area, Distributed Storage Systems, deals with problems arising from so-called cloud federations, i.e., when several cloud providers are needed to fulfill a given task.}}, author = {{Kniesburges, Sebastian and Markarian, Christine and Meyer auf der Heide, Friedhelm and Scheideler, Christian}}, booktitle = {{Proceedings of the 21st International Colloquium on Structural Information and Communication Complexity (SIROCCO)}}, pages = {{1--13}}, title = {{{Algorithmic Aspects of Resource Management in the Cloud}}}, doi = {{10.1007/978-3-319-09620-9_1}}, year = {{2014}}, } @article{464, abstract = {{Topological self-stabilization is an important concept to build robust open distributed systems (such as peer-to-peer systems) where nodes can organize themselves into meaningful network topologies. The goal is to devise distributed algorithms where nodes forward, insert, and delete links to neighboring nodes, and that converge quickly to such a desirable topology, independently of the initial network configuration. This article proposes a new model to study the parallel convergence time. Our model sheds light on the achievable parallelism by avoiding bottlenecks of existing models that can yield a distorted picture. As a case study, we consider local graph linearization—i.e., how to build a sorted list of the nodes of a connected graph in a distributed and self-stabilizing manner. In order to study the main structure and properties of our model, we propose two variants of a most simple local linearization algorithm. For each of these variants, we present analyses of the worst-case and bestcase parallel time complexities, as well as the performance under a greedy selection of the actions to be executed. It turns out that the analysis is non-trivial despite the simple setting, and to complement our formal insights we report on our experiments which indicate that the runtimes may be better in the average case.}}, author = {{Gall, Dominik and Jacob, Riko and Richa, Andrea W. and Scheideler, Christian and Schmid, Stefan and Täubig, Hanjo }}, journal = {{Theory of Computing Systems}}, number = {{1}}, pages = {{110--135}}, publisher = {{Springer}}, title = {{{A Note on the Parallel Runtime of Self-Stabilizing Graph Linearization}}}, doi = {{10.1007/s00224-013-9504-x}}, year = {{2014}}, } @inproceedings{393, abstract = {{A fundamental problem for peer-to-peer systems is to maintain connectivity while nodes are leaving, i.e., the nodes requesting to leave the peer-to-peer system are excluded from the overlay network without affecting its connectivity. There are a number of studies for safe node exclusion if the overlay is in a well-defined state initially. Surprisingly, the problem is not formally studied yet for the case in which the overlay network is in an arbitrary initial state, i.e., when looking for a self-stabilizing solution for excluding leaving nodes. We study this problem in two variants: the Finite Departure Problem (FDP) ) and the Finite Sleep Problem (FSP). In the FDP the leaving nodes have to irrevocably decide when it is safe to leave the network, whereas in the FSP, this leaving decision does not have to be final: the nodes may resume computation if necessary. We show that there is no self-stabilizing distributed algorithm for the FDP, even in a synchronous message passing model. To allow a solution, we introduce an oracle called NIDEC and show that it is sufficient even for the asynchronous message passing model by proposing an algorithm that can solve the FDP using NIDEC. We also show that a solution to the FSP does not require an oracle.}}, author = {{Foreback, Dianne and Koutsopoulos, Andreas and Nesterenko, Mikhail and Scheideler, Christian and Strothmann, Thim Frederik}}, booktitle = {{Proceedings of the 16th International Symposium on Stabilization, Safety, and Security of Distributed Systems}}, pages = {{48----62}}, title = {{{On Stabilizing Departures in Overlay Networks}}}, doi = {{10.1007/978-3-319-11764-5_4}}, year = {{2014}}, } @inproceedings{397, abstract = {{We present a factor $14D^2$ approximation algorithm for the minimum linear arrangement problem on series-parallel graphs, where $D$ is the maximum degree in the graph. Given a suitable decomposition of the graph, our algorithm runs in time $O(|E|)$ and is very easy to implement. Its divide-and-conquer approach allows for an effective parallelization. Note that a suitable decomposition can also be computed in time $O(|E|\log{|E|})$ (or even $O(\log{|E|}\log^*{|E|})$ on an EREW PRAM using $O(|E|)$ processors). For the proof of the approximation ratio, we use a sophisticated charging method that uses techniques similar to amortized analysis in advanced data structures. On general graphs, the minimum linear arrangement problem is known to be NP-hard. To the best of our knowledge, the minimum linear arrangement problem on series-parallel graphs has not been studied before.}}, author = {{Scheideler, Christian and Eikel, Martina and Setzer, Alexander}}, booktitle = {{Proceedings of the 12th Workshop on Approximation and Online Algorithms (WAOA)}}, pages = {{168----180}}, title = {{{Minimum Linear Arrangement of Series-Parallel Graphs}}}, year = {{2014}}, } @inproceedings{412, abstract = {{In this paper we present and analyze HSkip+, a self-stabilizing overlay network for nodes with arbitrary heterogeneous bandwidths. HSkip+ has the same topology as the Skip+ graph proposed by Jacob et al. [PODC 2009] but its self-stabilization mechanism significantly outperforms the self-stabilization mechanism proposed for Skip+. Also, the nodes are now ordered according to their bandwidths and not according to their identifiers. Various other solutions have already been proposed for overlay networks with heterogeneous bandwidths, but they are not self-stabilizing. In addition to HSkip+ being self-stabilizing, its performance is on par with the best previous bounds on the time and work for joining or leaving a network of peers of logarithmic diameter and degree and arbitrary bandwidths. Also, the dilation and congestion for routing messages is on par with the best previous bounds for such networks, so that HSkip+ combines the advantages of both worlds. Our theoretical investigations are backed by simulations demonstrating that HSkip+ is indeed performing much better than Skip+ and working correctly under high churn rates.}}, author = {{Feldotto, Matthias and Scheideler, Christian and Graffi, Kalman}}, booktitle = {{Proceedings of the 14th IEEE International Conference on Peer-to-Peer Computing (P2P)}}, pages = {{1--10}}, title = {{{HSkip+: A Self-Stabilizing Overlay Network for Nodes with Heterogeneous Bandwidths}}}, doi = {{10.1109/P2P.2014.6934300}}, year = {{2014}}, } @article{1868, author = {{W. Richa, Andr{\'{e}}a and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, journal = {{Distributed Computing}}, number = {{3}}, pages = {{159----171}}, title = {{{Competitive throughput in multi-hop wireless networks despite adaptive jamming}}}, doi = {{10.1007/s00446-012-0180-x}}, year = {{2013}}, } @article{1870, author = {{Mohd Nor, Rizal and Nesterenko, Mikhail and Scheideler, Christian}}, journal = {{Theor. Comput. Sci.}}, pages = {{119----129}}, title = {{{Corona: A stabilizing deterministic message-passing skip list}}}, doi = {{10.1016/j.tcs.2012.08.029}}, year = {{2013}}, } @article{1871, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, journal = {{IEEE/ACM Trans. Netw.}}, number = {{3}}, pages = {{760----771}}, title = {{{An Efficient and Fair MAC Protocol Robust to Reactive Interference}}}, doi = {{10.1109/TNET.2012.2210241}}, year = {{2013}}, } @article{476, abstract = {{An elementary h-route ow, for an integer h 1, is a set of h edge- disjoint paths between a source and a sink, each path carrying a unit of ow, and an h-route ow is a non-negative linear combination of elementary h-routeows. An h-route cut is a set of edges whose removal decreases the maximum h-route ow between a given source-sink pair (or between every source-sink pair in the multicommodity setting) to zero. The main result of this paper is an approximate duality theorem for multicommodity h-route cuts and ows, for h 3: The size of a minimum h-route cut is at least f=h and at most O(log4 k f) where f is the size of the maximum h-routeow and k is the number of commodities. The main step towards the proof of this duality is the design and analysis of a polynomial-time approximation algorithm for the minimum h-route cut problem for h = 3 that has an approximation ratio of O(log4 k). Previously, polylogarithmic approximation was known only for h-route cuts for h 2. A key ingredient of our algorithm is a novel rounding technique that we call multilevel ball-growing. Though the proof of the duality relies on this algorithm, it is not a straightforward corollary of it as in the case of classical multicommodity ows and cuts. Similar results are shown also for the sparsest multiroute cut problem.}}, author = {{Kolman, Petr and Scheideler, Christian}}, journal = {{Theory of Computing Systems}}, number = {{2}}, pages = {{341--363}}, publisher = {{Springer}}, title = {{{Towards Duality of Multicommodity Multiroute Cuts and Flows: Multilevel Ball-Growing}}}, doi = {{10.1007/s00224-013-9454-3}}, year = {{2013}}, } @inproceedings{513, abstract = {{This paper initiates the study of self-adjusting networks (or distributed data structures) whose topologies dynamically adapt to a communication pattern $\sigma$. We present a fully decentralized self-adjusting solution called SplayNet. A SplayNet is a distributed generalization of the classic splay tree concept. It ensures short paths (which can be found using local-greedy routing) between communication partners while minimizing topological rearrangements. We derive an upper bound for the amortized communication cost of a SplayNet based on empirical entropies of $\sigma$, and show that SplayNets have several interesting convergence properties. For instance, SplayNets features a provable online optimality under special requests scenarios. We also investigate the optimal static network and prove different lower bounds for the average communication cost based on graph cuts and on the empirical entropy of the communication pattern $\sigma$. From these lower bounds it follows, e.g., that SplayNets are optimal in scenarios where the requests follow a product distribution as well. Finally, this paper shows that in contrast to the Minimum Linear Arrangement problem which is generally NP-hard, the optimal static tree network can be computed in polynomial time for any guest graph, despite the exponentially large graph family. We complement our formal analysis with a small simulation study on a Facebook graph.}}, author = {{Avin, Chen and Häupler, Bernhard and Lotker, Zvi and Scheideler, Christian and Schmid, Stefan}}, booktitle = {{Proceedings of the 27th IEEE International Parallel and Distributed Processing Symposium (IPDPS)}}, pages = {{395--406}}, title = {{{Locally Self-Adjusting Tree Networks}}}, doi = {{10.1109/IPDPS.2013.40}}, year = {{2013}}, } @inproceedings{519, abstract = {{In this work we present the first scalable distributed information system,i.e., a system with low storage overhead, that is provably robust againstDenial-of-Service (DoS) attacks by a current insider. We allow acurrent insider to have complete knowledge about the information systemand to have the power to block any \epsilon-fraction of its serversby a DoS-attack, where \epsilon can be chosen up to a constant. The taskof the system is to serve any collection of lookup requests with at most oneper non-blocked server in an efficient way despite this attack. Previously,scalable solutions were only known for DoS-attacks of past insiders, where apast insider only has complete knowledge about some past time pointt_0 of the information system. Scheideler et al. (DISC 2007, SPAA 2009) showedthat in this case it is possible to design an information system so that anyinformation that was inserted or last updated after t_0 is safe against a DoS-attack. But their constructions would not work at all for a current insider. The key idea behindour IRIS system is to make extensive use of coding. More precisely, we presenttwo alternative distributed coding strategies with an at most logarithmicstorage overhead that can handle up to a constant fraction of blocked servers.}}, author = {{Eikel, Martina and Scheideler, Christian}}, booktitle = {{Proceedings of the 25th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)}}, pages = {{119--129}}, title = {{{IRIS: A Robust Information System Against Insider DoS-Attacks}}}, doi = {{10.1145/2486159.2486186}}, year = {{2013}}, } @inproceedings{542, abstract = {{We consider the problem of managing a dynamic heterogeneous storagesystem in a distributed way so that the amount of data assigned to a hostin that system is related to its capacity. Two central problems have to be solvedfor this: (1) organizing the hosts in an overlay network with low degree and diameterso that one can efficiently check the correct distribution of the data androute between any two hosts, and (2) distributing the data among the hosts so thatthe distribution respects the capacities of the hosts and can easily be adapted asthe set of hosts or their capacities change. We present distributed protocols forthese problems that are self-stabilizing and that do not need any global knowledgeabout the system such as the number of nodes or the overall capacity of thesystem. Prior to this work no solution was known satisfying these properties.}}, author = {{Kniesburges, Sebastian and Koutsopoulos, Andreas and Scheideler, Christian}}, booktitle = {{Proceedings of the 27th International Symposium on Distributed Computing (DISC)}}, pages = {{537--549}}, title = {{{CONE-DHT: A distributed self-stabilizing algorithm for a heterogeneous storage system}}}, doi = {{10.1007/978-3-642-41527-2_37}}, year = {{2013}}, } @inproceedings{564, abstract = {{We consider the problem of resource discovery in distributed systems. In particular we give an algorithm, such that each node in a network discovers the add ress of any other node in the network. We model the knowledge of the nodes as a virtual overlay network given by a directed graph such that complete knowledge of all nodes corresponds to a complete graph in the overlay network. Although there are several solutions for resource discovery, our solution is the first that achieves worst-case optimal work for each node, i.e. the number of addresses (O(n)) or bits (O(nlogn)) a node receives or sendscoincides with the lower bound, while ensuring only a linearruntime (O(n)) on the number of rounds.}}, author = {{Kniesburges, Sebastian and Koutsopoulos, Andreas and Scheideler, Christian}}, booktitle = {{Proceedings of 20th International Colloqium on Structural Information and Communication Complexity (SIROCCO)}}, pages = {{165--176}}, title = {{{A Deterministic Worst-Case Message Complexity Optimal Solution for Resource Discovery}}}, doi = {{10.1007/978-3-319-03578-9_14}}, year = {{2013}}, } @article{1882, author = {{Dolev, Shlomi and Scheideler, Christian}}, journal = {{Theor. Comput. Sci.}}, pages = {{1}}, title = {{{Editorial for Algorithmic Aspects of Wireless Sensor Networks}}}, doi = {{10.1016/j.tcs.2012.07.012}}, year = {{2012}}, } @inproceedings{1884, author = {{Monien, Burkhard and Scheideler, Christian}}, booktitle = {{Euro-Par 2012 Parallel Processing - 18th International Conference, Euro-Par 2012, Rhodes Island, Greece, August 27-31, 2012. Proceedings}}, isbn = {{978-3-642-32819-0}}, pages = {{1----2}}, publisher = {{Springer}}, title = {{{Selfish Distributed Optimization}}}, doi = {{10.1007/978-3-642-32820-6_1}}, volume = {{7484}}, year = {{2012}}, } @article{570, abstract = {{This article studies the construction of self-stabilizing topologies for distributed systems. While recent research has focused on chain topologies where nodes need to be linearized with respect to their identiers, we explore a natural and relevant 2-dimensional generalization. In particular, we present a local self-stabilizing algorithm DStab which is based on the concept of \local Delaunay graphs" and which forwards temporary edges in greedy fashion reminiscent of compass routing. DStab constructs a Delaunay graph from any initial connected topology and in a distributed manner in time O(n3) in the worst-case; if the initial network contains the Delaunay graph, the convergence time is only O(n) rounds. DStab also ensures that individual node joins and leaves aect a small part of the network only. Such self-stabilizing Delaunay networks have interesting applications and our construction gives insights into the necessary geometric reasoning that is required for higherdimensional linearization problems.Keywords: Distributed Algorithms, Topology Control, Social Networks}}, author = {{Jacob, Riko and Ritscher, Stephan and Scheideler, Christian and Schmid, Stefan}}, journal = {{Theoretical Computer Science}}, pages = {{137--148}}, publisher = {{Elsevier}}, title = {{{Towards higher-dimensional topological self-stabilization: A distributed algorithm for Delaunay graphs}}}, doi = {{10.1016/j.tcs.2012.07.029}}, year = {{2012}}, } @article{574, abstract = {{We present Tiara — a self-stabilizing peer-to-peer network maintenance algorithm. Tiara is truly deterministic which allows it to achieve exact performance bounds. Tiara allows logarithmic searches and topology updates. It is based on a novel sparse 0-1 skip list. We then describe its extension to a ringed structure and to a skip-graph.Key words: Peer-to-peer networks, overlay networks, self-stabilization.}}, author = {{Clouser, Thomas and Nesterenko, Mikhail and Scheideler, Christian}}, journal = {{Theoretical Computer Science}}, pages = {{18--35}}, publisher = {{Elsevier}}, title = {{{Tiara: A self-stabilizing deterministic skip list and skip graph}}}, doi = {{10.1016/j.tcs.2011.12.079}}, year = {{2012}}, }