@article{579, abstract = {{A left-to-right maximum in a sequence of n numbers s_1, …, s_n is a number that is strictly larger than all preceding numbers. In this article we present a smoothed analysis of the number of left-to-right maxima in the presence of additive random noise. We show that for every sequence of n numbers s_i ∈ [0,1] that are perturbed by uniform noise from the interval [-ε,ε], the expected number of left-to-right maxima is Θ(&sqrt;n/ε + log n) for ε>1/n. For Gaussian noise with standard deviation σ we obtain a bound of O((log3/2 n)/σ + log n).We apply our results to the analysis of the smoothed height of binary search trees and the smoothed number of comparisons in the quicksort algorithm and prove bounds of Θ(&sqrt;n/ε + log n) and Θ(n/ε+1&sqrt;n/ε + n log n), respectively, for uniform random noise from the interval [-ε,ε]. Our results can also be applied to bound the smoothed number of points on a convex hull of points in the two-dimensional plane and to smoothed motion complexity, a concept we describe in this article. We bound how often one needs to update a data structure storing the smallest axis-aligned box enclosing a set of points moving in d-dimensional space.}}, author = {{Damerow, Valentina and Manthey, Bodo and Meyer auf der Heide, Friedhelm and Räcke, Harald and Scheideler, Christian and Sohler, Christian and Tantau, Till}}, journal = {{Transactions on Algorithms}}, number = {{3}}, pages = {{30}}, publisher = {{ACM}}, title = {{{Smoothed analysis of left-to-right maxima with applications}}}, doi = {{10.1145/2229163.2229174}}, year = {{2012}}, } @inproceedings{581, abstract = {{Nanoparticles are getting more and more in the focus of the scientic community since the potential for the development of very small particles interacting with each other and completing medical and other tasks is getting bigger year by year. In this work we introduce a distributed local algorithm for arranging a set of nanoparticles on the discrete plane into specic geometric shapes, for instance a rectangle. The concept of a particle we use can be seen as a simple mobile robot with the following restrictions: it can only view the state of robots it is physically connected to, is anonymous, has only a constant size memory, can only move by using other particles as an anchor point on which it pulls itself alongside, and it operates in Look-Compute-Move cycles. The main result of this work is the presentation of a random distributed local algorithm which transforms any given connected set of particles into a particular geometric shape. As an example we provide a version of this algorithm for forming a rectangle with an arbitrary predened aspect ratio. To the best of our knowledge this is the rst work that considers arrangement problems for these types of robots.}}, author = {{Drees, Maximilian and Hüllmann (married name: Eikel), Martina and Koutsopoulos, Andreas and Scheideler, Christian}}, booktitle = {{Proceedings of the 26th IEEE International Parallel and Distributed Processing Symposium (IPDPS)}}, pages = {{1272--1283}}, title = {{{Self-Organizing Particle Systems}}}, doi = {{10.1109/IPDPS.2012.116}}, year = {{2012}}, } @inproceedings{623, abstract = {{This paper initiates the formal study of a fundamental problem: How to efficiently allocate a shared communication medium among a set of K co-existing networks in the presence of arbitrary external interference? While most literature on medium access focuses on how to share a medium among nodes, these approaches are often either not directly applicable to co-existing networks as they would violate the independence requirement, or they yield a low throughput if applied to multiple networks. We present the randomized medium access (MAC) protocol COMAC which guarantees that a given communication channel is shared fairly among competing and independent networks, and that the available bandwidth is used efficiently. These performance guarantees hold in the presence of arbitrary external interference or even under adversarial jamming. Concretely, we show that the co-existing networks can use a Ω(ε2 min{ε, 1/poly(K)})-fraction of the non-jammed time steps for successful message transmissions, where ε is the (arbitrarily distributed) fraction of time which is not jammed.}}, author = {{Richa, Andrea W. and Scheideler, Christian and Schmid, Stefan and Zhang, Jin }}, booktitle = {{Proceedings of the 31st Annual ACM SIGACT-SIGOPS Symposium on Principles and Distributed Computing (PODC)}}, pages = {{291--300}}, title = {{{Competitive and fair throughput for co-existing networks under adversarial interference}}}, doi = {{10.1145/2332432.2332488}}, year = {{2012}}, } @inproceedings{625, abstract = {{This paper initiates the study of self-adjusting distributed data structures for networks. In particular, we present SplayNets: a binary search tree based network that is self-adjusting to routing request.We derive entropy bounds on the amortized routing cost and show that our splaying algorithm has some interesting properties.}}, author = {{Schmid, Stefan and Avin, Chen and Scheideler, Christian and Häupler, Bernhard and Lotker, Zvi}}, booktitle = {{Proceedings of the 26th International Symposium on Distributed Computing (DISC)}}, pages = {{439--440}}, title = {{{Brief Announcement: SplayNets - Towards Self-Adjusting Distributed Data Structures}}}, doi = {{10.1007/978-3-642-33651-5_47}}, year = {{2012}}, } @inproceedings{626, abstract = {{The design of ecient search structures for peer-to-peer systems has attracted a lot of attention in recent years. In this announcement we address the problem of nding the predecessor in a key set and present an ecient data structure called hashed Predecessor Patricia trie. Our hashed Predecessor Patricia trie supports PredecessorSearch(x) and Insert(x) and Delete(x) in O(log log u) hash table accesses when u is the size of the universe of the keys. That is the costs only depend on u and not the size of the data structure. One feature of our approach is that it only uses the lookup interface of the hash table and therefore hash table accesses may be realized by any distributed hash table (DHT).}}, author = {{Kniesburges, Sebastian and Scheideler, Christian}}, booktitle = {{Proceedings of the 26th International Symposium on Distributed Computing (DISC)}}, pages = {{435--436}}, title = {{{Brief Announcement: Hashed Predecessor Patricia Trie - A Data Structure for Efficient Predecessor Queries in Peer-to-Peer Systems}}}, doi = {{10.1007/978-3-642-33651-5_45}}, year = {{2012}}, } @inproceedings{632, abstract = {{Given an integer h, a graph G = (V;E) with arbitrary positive edge capacities and k pairs of vertices (s1; t1); (s2; t2); : : : ; (sk; tk), called terminals, an h-route cut is a set F µ E of edges such that after the removal of the edges in F no pair si ¡ ti is connected by h edge-disjoint paths (i.e., the connectivity of every si ¡ ti pair is at most h ¡ 1 in (V;E n F)). The h-route cut is a natural generalization of the classical cut problem for multicommodity °ows (take h = 1). The main result of this paper is an O(h722h log2 k)-approximation algorithm for the minimum h-route cut problem in the case that s1 = s2 = ¢ ¢ ¢ = sk, called the single source case. As a corollary of it we obtain an approximate duality theorem for multiroute multicom-modity °ows and cuts with a single source. This partially answers an open question posted in several previous papers dealing with cuts for multicommodity multiroute problems.}}, author = {{Kolman, Petr and Scheideler, Christian}}, booktitle = {{Proceedings of the 23th ACM SIAM Symposium on Discrete Algorithms (SODA)}}, pages = {{800--810}}, title = {{{Approximate Duality of Multicommodity Multiroute Flows and Cuts: Single Source Case}}}, doi = {{10.1137/1.9781611973099.64}}, year = {{2012}}, } @inproceedings{640, abstract = {{Small-world networks have received significant attention because of their potential as models for the interaction networks of complex systems. Specifically, neither random networks nor regular lattices seem to be an adequate framework within which to study real-world complex systems such as chemical-reaction networks, neural networks, food webs, social networks, scientific-collaboration networks, and computer networks. Small-world networks provide some desired properties like an expected polylogarithmic distance between two processes in the network, which allows routing in polylogarithmic hops by simple greedy routing, and robustness against attacks or failures. By these properties, small-world networks are possible solutions for large overlay networks comparable to structured overlay networks like CAN, Pastry, Chord, which also provide polylogarithmic routing, but due to their uniform structure, structured overlay networks are more vulnerable to attacks or failures. In this paper we bring together a randomized process converging to a small-world network and a self-stabilization process so that a small-world network is formed out of any weakly connected initial state. To the best of our knowledge this is the first distributed self-stabilization process for building a small-world network.}}, author = {{Kniesburges, Sebastian and Koutsopoulos, Andreas and Scheideler, Christian}}, booktitle = {{Proceedings of the 26th IEEE International Parallel and Distributed Processing Symposium (IPDPS)}}, pages = {{1261----1271}}, title = {{{A Self-Stabilization Process for Small-World Networks}}}, doi = {{10.1109/IPDPS.2012.115}}, year = {{2012}}, } @inproceedings{1891, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{2011 International Conference on Distributed Computing Systems, ICDCS 2011, Minneapolis, Minnesota, USA, June 20-24, 2011}}, isbn = {{978-0-7695-4364-2}}, pages = {{507----516}}, publisher = {{IEEE Computer Society}}, title = {{{Competitive and Fair Medium Access Despite Reactive Jamming}}}, doi = {{10.1109/ICDCS.2011.8}}, year = {{2011}}, } @inproceedings{1892, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{Proceedings of the 3rd ACM workshop on Wireless of the students, by the students, for the students, S3@MOBICOM 2011, Las Vegas, NV, USA, September 19 - 23, 2011}}, isbn = {{978-1-4503-0868-7}}, pages = {{33----36}}, publisher = {{ACM}}, title = {{{Towards jamming-resistant and competitive medium access in the SINR model}}}, doi = {{10.1145/2030686.2030697}}, year = {{2011}}, } @inproceedings{1893, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{Proceedings of the 12th ACM Interational Symposium on Mobile Ad Hoc Networking and Computing, MobiHoc 2011, Paris, France, May 16-20, 2011}}, isbn = {{978-1-4503-0722-2}}, pages = {{15}}, publisher = {{ACM}}, title = {{{Self-stabilizing leader election for single-hop wireless networks despite jamming}}}, doi = {{10.1145/2107502.2107522}}, year = {{2011}}, }