TY - JOUR
AU - Feldkord, Björn
AU - Knollmann, Till
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
ID - 20683
JF - Theory of Computing Systems
TI - Managing Multiple Mobile Resources
ER -
TY - CONF
AU - Bienkowski, Marcin
AU - Feldkord, Björn
AU - Schmidt, Pawel
ID - 20817
T2 - Proceedings of the 38th Symposium on Theoretical Aspects of Computer Science (STACS)
TI - A Nearly Optimal Deterministic Online Algorithm for Non-Metric Facility Location
ER -
TY - JOUR
AB - While many research in distributed computing has covered solutions for self-stabilizing computing and topologies, there is far less work on self-stabilization for distributed data structures. However, when peers in peer-to-peer networks crash, a distributed data structure may not remain intact. We present a self-stabilizing protocol for a distributed data structure called the Hashed Patricia Trie (Kniesburges and Scheideler WALCOM'11) that enables efficient prefix search on a set of keys. The data structure has many applications while offering low overhead and efficient operations when embedded on top of a Distributed Hash Table. Especially, longest prefix matching for x can be done in O(log |x|) hash table read accesses. We show how to maintain the structure in a self-stabilizing way, while assuring a low overhead in a legal state and an asymptotically optimal memory demand of O(d) bits, where d is the number of bits needed for storing all keys.
AU - Knollmann, Till
AU - Scheideler, Christian
ID - 21096
JF - Information and Computation
SN - 0890-5401
TI - A self-stabilizing Hashed Patricia Trie
ER -
TY - CONF
AB - We consider a natural extension to the metric uncapacitated Facility Location Problem (FLP) in which requests ask for different commodities out of a finite set \( S \) of commodities.
Ravi and Sinha (SODA 2004) introduced the model as the \emph{Multi-Commodity Facility Location Problem} (MFLP) and considered it an offline optimization problem.
The model itself is similar to the FLP: i.e., requests are located at points of a finite metric space and the task of an algorithm is to construct facilities and assign requests to facilities while minimizing the construction cost and the sum over all assignment distances.
In addition, requests and facilities are heterogeneous; they request or offer multiple commodities out of $S$.
A request has to be connected to a set of facilities jointly offering the commodities demanded by it.
In comparison to the FLP, an algorithm has to decide not only if and where to place facilities, but also which commodities to offer at each.
To the best of our knowledge we are the first to study the problem in its online variant in which requests, their positions and their commodities are not known beforehand but revealed over time.
We present results regarding the competitive ratio.
On the one hand, we show that heterogeneity influences the competitive ratio by developing a lower bound on the competitive ratio for any randomized online algorithm of \( \Omega ( \sqrt{|S|} + \frac{\log n}{\log \log n} ) \) that already holds for simple line metrics.
Here, \( n \) is the number of requests.
On the other side, we establish a deterministic \( \mathcal{O}(\sqrt{|S|} \cdot \log n) \)-competitive algorithm and a randomized \( \mathcal{O}(\sqrt{|S|} \cdot \frac{\log n}{\log \log n} ) \)-competitive algorithm.
Further, we show that when considering a more special class of cost functions for the construction cost of a facility, the competitive ratio decreases given by our deterministic algorithm depending on the function.
AU - Castenow, Jannik
AU - Feldkord, Björn
AU - Knollmann, Till
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
ID - 17370
KW - Online Multi-Commodity Facility Location
KW - Competitive Ratio
KW - Online Optimization
KW - Facility Location Problem
SN - 9781450369350
T2 - Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures
TI - The Online Multi-Commodity Facility Location Problem
ER -
TY - CONF
AU - Castenow, Jannik
AU - Kling, Peter
AU - Knollmann, Till
AU - Meyer auf der Heide, Friedhelm
ID - 17371
SN - 9781450369350
T2 - Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures
TI - Brief Announcement: A Discrete and Continuous Study of the Max-Chain-Formation Problem: Slow Down to Speed up
ER -
TY - CONF
AU - Pukrop, Simon
AU - Mäcker, Alexander
AU - Meyer auf der Heide, Friedhelm
ID - 13868
T2 - Proceedings of the 46th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM)
TI - Approximating Weighted Completion Time for Order Scheduling with Setup Times
ER -
TY - THES
AU - Feldkord, Björn
ID - 15631
TI - Mobile Resource Allocation
ER -
TY - CONF
AB - Let G = (V,E) be an undirected graph on n vertices with non-negative capacities on its edges. The mincut sensitivity problem for the insertion of an edge is defined as follows. Build a compact data structure for G and a given set S ⊆ V of vertices that, on receiving any edge (x,y) ∈ S×S of positive capacity as query input, can efficiently report the set of all pairs from S× S whose mincut value increases upon insertion of the edge (x,y) to G. The only result that exists for this problem is for a single pair of vertices (Picard and Queyranne, Mathematical Programming Study, 13 (1980), 8-16). We present the following results for the single source and the all-pairs versions of this problem.
1) Single source: Given any designated source vertex s, there exists a data structure of size 𝒪(|S|) that can output all those vertices from S whose mincut value to s increases upon insertion of any given edge. The time taken by the data structure to answer any query is 𝒪(|S|).
2) All-pairs: There exists an 𝒪(|S|²) size data structure that can output all those pairs of vertices from S× S whose mincut value gets increased upon insertion of any given edge. The time taken by the data structure to answer any query is 𝒪(k), where k is the number of pairs of vertices whose mincut increases.
For both these versions, we also address the problem of reporting the values of the mincuts upon insertion of any given edge. To derive our results, we use interesting insights into the nearest and the farthest mincuts for a pair of vertices. In addition, a crucial result, that we establish and use in our data structures, is that there exists a directed acyclic graph of 𝒪(n) size that compactly stores the farthest mincuts from all vertices of V to a designated vertex s in the graph. We believe that this result is of independent interest, especially, because it also complements a previously existing result by Hariharan et al. (STOC 2007) that the nearest mincuts from all vertices of V to s is a laminar family, and hence, can be stored compactly in a tree of 𝒪(n) size.
AU - Baswana, Surender
AU - Gupta, Shiv
AU - Knollmann, Till
ED - Grandoni, Fabrizio
ED - Herman, Grzegorz
ED - Sanders, Peter
ID - 20159
KW - Mincut
KW - Sensitivity
KW - Data Structure
SN - 1868-8969
T2 - 28th Annual European Symposium on Algorithms (ESA 2020)
TI - Mincut Sensitivity Data Structures for the Insertion of an Edge
VL - 173
ER -
TY - CONF
AB - In this work, we initiate the research about the Gathering problem for robots
with limited viewing range in the three-dimensional Euclidean space. In the
Gathering problem, a set of initially scattered robots is required to gather at
the same position. The robots' capabilities are very restricted -- they do not
agree on any coordinate system or compass, have a limited viewing range, have
no memory of the past and cannot communicate. We study the problem in two
different time models, in FSYNC (fully synchronized discrete rounds) and the
continuous time model. For FSYNC, we introduce the 3D-Go-To-The-Center-strategy
and prove a runtime of $\Theta(n^2)$ that matches the currently best runtime
bound for the same model in the Euclidean plane [SPAA'11]. Our main result is
the generalization of contracting strategies (continuous time) from
[Algosensors'17] to three dimensions. In contracting strategies, every robot
that is located on the global convex hull of all robots' positions moves with
full speed towards the inside of the convex hull. We prove a runtime bound of
$O(\Delta \cdot n^{3/2})$ for any three-dimensional contracting strategy, where
$\Delta$ denotes the diameter of the initial configuration. This comes up to a
factor of $\sqrt{n}$ close to the lower bound of $\Omega (\Delta \cdot n)$
which is already true in two dimensions. In general, it might be hard for
robots with limited viewing range to decide whether they are located on the
global convex hull and which movement maintains the connectivity of the swarm,
rendering the design of concrete contracting strategies a challenging task. We
prove that the continuous variant of 3D-Go-To-The-Center is contracting and
keeps the swarm connected. Moreover, we give a simple design criterion for
three-dimensional contracting strategies that maintains the connectivity of the
swarm and introduce an exemplary strategy based on this criterion.
AU - Braun, Michael
AU - Castenow, Jannik
AU - Meyer auf der Heide, Friedhelm
ID - 16968
T2 - Proceedings of the 27th Conference on Structural Information and Communication Complexity (SIROCCO)
TI - Local Gathering of Mobile Robots in Three Dimensions
ER -
TY - CONF
AU - Castenow, Jannik
AU - Harbig, Jonas
AU - Jung, Daniel
AU - Knollmann, Till
AU - Meyer auf der Heide, Friedhelm
ED - Devismes, Stéphane
ED - Mittal, Neeraj
ID - 20185
SN - 978-3-030-64347-8
T2 - Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings
TI - Brief Announcement: Gathering in Linear Time: A Closed Chain of Disoriented & Luminous Robots with Limited Visibility
VL - 12514
ER -
TY - JOUR
AU - Karl, Holger
AU - Kundisch, Dennis
AU - Meyer auf der Heide, Friedhelm
AU - Wehrheim, Heike
ID - 13770
IS - 6
JF - Business & Information Systems Engineering
TI - A Case for a New IT Ecosystem: On-The-Fly Computing
VL - 62
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 - JOUR
AU - Castenow, Jannik
AU - Fischer, Matthias
AU - Harbig, Jonas
AU - Jung, Daniel
AU - Meyer auf der Heide, Friedhelm
ID - 16299
JF - Theoretical Computer Science
SN - 0304-3975
TI - Gathering Anonymous, Oblivious Robots on a Grid
VL - 815
ER -
TY - CONF
AB - Most existing robot formation problems seek a target formation of a certain
minimal and, thus, efficient structure. Examples include the Gathering
and the Chain-Formation problem. In this work, we study formation problems that
try to reach a maximal structure, supporting for example an efficient
coverage in exploration scenarios. A recent example is the NASA Shapeshifter
project, which describes how the robots form a relay chain along which gathered
data from extraterrestrial cave explorations may be sent to a home base.
As a first step towards understanding such maximization tasks, we introduce
and study the Max-Chain-Formation problem, where $n$ robots are ordered along a
winding, potentially self-intersecting chain and must form a connected,
straight line of maximal length connecting its two endpoints. We propose and
analyze strategies in a discrete and in a continuous time model. In the
discrete case, we give a complete analysis if all robots are initially
collinear, showing that the worst-case time to reach an
$\varepsilon$-approximation is upper bounded by $\mathcal{O}(n^2 \cdot \log
(n/\varepsilon))$ and lower bounded by $\Omega(n^2 \cdot~\log
(1/\varepsilon))$. If one endpoint of the chain remains stationary, this result
can be extended to the non-collinear case. If both endpoints move, we identify
a family of instances whose runtime is unbounded. For the continuous model, we
give a strategy with an optimal runtime bound of $\Theta(n)$. Avoiding an
unbounded runtime similar to the discrete case relies crucially on a
counter-intuitive aspect of the strategy: slowing down the endpoints while all
other robots move at full speed. Surprisingly, we can show that a similar trick
does not work in the discrete model.
AU - Castenow, Jannik
AU - Kling, Peter
AU - Knollmann, Till
AU - Meyer auf der Heide, Friedhelm
ED - Devismes , Stéphane
ED - Mittal, Neeraj
ID - 19899
SN - 978-3-030-64347-8
T2 - Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings
TI - A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up
VL - 12514
ER -
TY - CONF
AU - Feldkord, Björn
AU - Knollmann, Till
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
ID - 12870
T2 - Proceedings of the 17th Workshop on Approximation and Online Algorithms (WAOA)
TI - Managing Multiple Mobile Resources
ER -
TY - JOUR
AU - Feldkord, Björn
AU - Meyer auf der Heide, Friedhelm
ID - 13873
IS - 3
JF - ACM Transactions on Parallel Computing (TOPC)
TI - The Mobile Server Problem
VL - 6
ER -
TY - GEN
AB - We present a technique for rendering highly complex 3D scenes in real-time by
generating uniformly distributed points on the scene's visible surfaces. The
technique is applicable to a wide range of scene types, like scenes directly
based on complex and detailed CAD data consisting of billions of polygons (in
contrast to scenes handcrafted solely for visualization). This allows to
visualize such scenes smoothly even in VR on a HMD with good image quality,
while maintaining the necessary frame-rates. In contrast to other point based
rendering methods, we place points in an approximated blue noise distribution
only on visible surfaces and store them in a highly GPU efficient data
structure, allowing to progressively refine the number of rendered points to
maximize the image quality for a given target frame rate. Our evaluation shows
that scenes consisting of a high amount of polygons can be rendered with
interactive frame rates with good visual quality on standard hardware.
AU - Brandt, Sascha
AU - Jähn, Claudius
AU - Fischer, Matthias
AU - Meyer auf der Heide, Friedhelm
ID - 16341
T2 - arXiv:1904.08225
TI - Rendering of Complex Heterogenous Scenes using Progressive Blue Surfels
ER -
TY - THES
AB - This thesis investigates approximate pure Nash equilibria in different game-theoretic models. In such an outcome, no player can improve her objective by more than a given factor through a deviation to another strategy. In the first part, we investigate two variants of Congestion Games in which the existence of pure Nash equilibria is guaranteed through a potential function argument. However, the computation of such equilibria might be hard. We construct and analyze approximation algorithms that enable the computation of states with low approximation factors in polynomial time. To show their guarantees we use sub games among players, bound the potential function values of arbitrary states and exploit a connection between Shapley and proportional cost shares. Furthermore, we apply and analyze sampling techniques for the computation of approximate Shapley values in different settings. In the second part, we concentrate on the existence of approximate pure Nash equilibria in games in which no pure Nash equilibria exist in general. In the model of Coevolving Opinion Formation Games, we bound the approximation guarantees for natural states nearly independent of the specific definition of the players' neighborhoods by applying a concept of virtual costs. For the special case of only one influential neighbor, we even show lower approximation factors for a natural strategy. Then, we investigate a two-sided Facility Location Game among facilities and clients on a line with an objective function consisting of distance and load. We show tight bounds on the approximation factor for settings with three facilities and infinitely many clients. For the general scenario with an arbitrary number of facilities, we bound the approximation factor for two promising candidates, namely facilities that are uniformly distributed and which are paired.
AU - Feldotto, Matthias
ID - 8080
TI - Approximate Pure Nash Equilibria in Congestion, Opinion Formation and Facility Location Games
ER -
TY - CONF
AB - Competing firms tend to select similar locations for their stores. This phenomenon, called the principle of minimum differentiation, was captured by Hotelling with a landmark model of spatial competition but is still the object of an ongoing scientific debate. Although consistently observed in practice, many more realistic variants of Hotelling's model fail to support minimum differentiation or do not have pure equilibria at all. In particular, it was recently proven for a generalized model which incorporates negative network externalities and which contains Hotelling's model and classical selfish load balancing as special cases, that the unique equilibria do not adhere to minimum differentiation. Furthermore, it was shown that for a significant parameter range pure equilibria do not exist. We derive a sharp contrast to these previous results by investigating Hotelling's model with negative network externalities from an entirely new angle: approximate pure subgame perfect equilibria. This approach allows us to prove analytically and via agent-based simulations that approximate equilibria having good approximation guarantees and that adhere to minimum differentiation exist for the full parameter range of the model. Moreover, we show that the obtained approximate equilibria have high social welfare.
AU - Feldotto, Matthias
AU - Lenzner, Pascal
AU - Molitor, Louise
AU - Skopalik, Alexander
ID - 10281
T2 - Proceedings of the 18th International Conference on Autonomous Agents and MultiAgent Systems
TI - From Hotelling to Load Balancing: Approximation and the Principle of Minimum Differentiation
ER -
TY - JOUR
AU - Meyer auf der Heide, Friedhelm
ID - 13937
IS - 2
JF - Mathematische Semesterberichte
TI - Paul Curzon, Peter W. McOwan: Computational Thinking; Die Welt des algorithmischen Denkens – in Spielen, Zaubertricks und Rätseln
VL - 66
ER -
TY - THES
AU - Malatyali, Manuel
ID - 18975
TI - Big Data: Sublinear Algorithms for Distributed Data Streams
ER -
TY - GEN
AU - Pukrop, Simon
ID - 10344
TI - Scheduling Algorithms for Multi-Operation Jobs with Setups on a Single Machine
ER -
TY - CONF
AB - Resolving distributed attacks benefits from collaboration between networks. We present three approaches for the same multi-domain defensive action that can be applied in such an alliance: 1) Counteract Everywhere, 2) Minimize Countermeasures, and 3) Minimize Propagation. First, we provide a formula to compute efficiency of a defense; then we use this formula to compute the efficiency of the approaches under various circumstances. Finally, we discuss how task execution order and timing influence defense efficiency. Our results show that the Minimize Propagation approach is the most efficient method when defending against the chosen attack.
AU - Koning, Ralph
AU - Polevoy, Gleb
AU - Meijer, Lydia
AU - de Laat, Cees
AU - Grosso, Paola
ID - 17667
KW - computer network security
KW - multinetwork environments
KW - multidomain defensive action
KW - task execution order
KW - timing influence defense efficiency
KW - distributed attacks
KW - collaborative security defence approach
KW - minimize propagation approach
KW - minimize countermeasure approach
KW - counteract everywhere approach
KW - Conferences
KW - Cloud computing
KW - Computer crime
KW - Edge computing
KW - Security
KW - Defense Approaches
KW - Multi-Domain Defense
KW - Collaborative Defense
KW - Defense Algorithms
KW - Computer Networks
SN - null
T2 - 2019 6th IEEE International Conference on Cyber Security and Cloud Computing (CSCloud)/ 2019 5th IEEE International Conference on Edge Computing and Scalable Cloud (EdgeCom)
TI - Approaches for Collaborative Security Defences in Multi Network Environments
ER -
TY - CONF
AU - Jansen, Klaus
AU - Maack, Marten
AU - Mäcker, Alexander
ID - 8866
T2 - Proceedings of the 33rd IEEE International Parallel and Distributed Processing Symposium (IPDPS)
TI - Scheduling on (Un-)Related Machines with Setup Times
ER -
TY - CHAP
AU - Kling, Peter
AU - Meyer auf der Heide, Friedhelm
ID - 13939
T2 - Distributed Computing by Mobile Entities, Current Research in Moving and Computing
TI - Continuous Protocols for Swarm Robotics
VL - 11340
ER -
TY - CONF
AB - We characterise the set of dominant strategy incentive compatible (DSIC), strongly budget balanced (SBB), and ex-post individually rational (IR) mechanisms for the multi-unit bilateral trade setting. In such a setting there is a single buyer and a single seller who holds a finite number k of identical items. The mechanism has to decide how many units of the item are transferred from the seller to the buyer and how much money is transferred from the buyer to the seller. We consider two classes of valuation functions for the buyer and seller: Valuations that are increasing in the number of units in possession, and the more specific class of valuations that are increasing and submodular.
Furthermore, we present some approximation results about the performance of certain such mechanisms, in terms of social welfare: For increasing submodular valuation functions, we show the existence of a deterministic 2-approximation mechanism and a randomised e/(1-e) approximation mechanism, matching the best known bounds for the single-item setting.
AU - Lazos, Philip
AU - Goldberg, Paul
AU - Skopalik, Alexander
AU - Gerstgrasser, Matthias
AU - de Keijzer, Bart
ID - 5471
T2 - Proceedings of the Thirty-Third AAAI Conference on Artificial Intelligence (AAAI)
TI - Multi-unit Bilateral Trade
ER -
TY - JOUR
AU - Abu-Khzam, Faisal N.
AU - Li, Shouwei
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
AU - Podlipyan, Pavel
ID - 13946
JF - Theoretical Computer Science
TI - Efficient parallel algorithms for parameterized problems
VL - 786
ER -
TY - CONF
AU - Castenow, Jannik
AU - Kolb, Christina
AU - Scheideler, Christian
ID - 14539
T2 - Proceedings of the 26th International Colloquium on Structural Information and Communication Complexity (SIROCCO)
TI - A Bounding Box Overlay for Competitive Routing in Hybrid Communication Networks
ER -
TY - CONF
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
ID - 13942
T2 - Proceedings of the 8th International Conference on Operations Research and Enterprise Systems
TI - Online Algorithms for Leasing Vertex Cover and Leasing Non-metric Facility Location
ER -
TY - CONF
AU - Baswana, Surender
AU - Gupta, Shiv
AU - Tulsyan, Ayush
ID - 17432
T2 - 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019)
TI - Fault Tolerant and Fully Dynamic DFS in Undirected Graphs: Simple Yet Efficient
ER -
TY - THES
AU - Mäcker, Alexander
ID - 14851
TI - On Scheduling with Setup Times
ER -
TY - JOUR
AB - In software engineering, the imprecise requirements of a user are transformed to a formal requirements specification during the requirements elicitation process. This process is usually guided by requirements engineers interviewing the user. We want to partially automate this first step of the software engineering process in order to enable users to specify a desired software system on their own. With our approach, users are only asked to provide exemplary behavioral descriptions. The problem of synthesizing a requirements specification from examples can partially be reduced to the problem of grammatical inference, to which we apply an active coevolutionary learning approach. However, this approach would usually require many feedback queries to be sent to the user. In this work, we extend and generalize our active learning approach to receive knowledge from multiple oracles, also known as proactive learning. The ‘user oracle’ represents input received from the user and the ‘knowledge oracle’ represents available, formalized domain knowledge. We call our two-oracle approach the ‘first apply knowledge then query’ (FAKT/Q) algorithm. We compare FAKT/Q to the active learning approach and provide an extensive benchmark evaluation. As result we find that the number of required user queries is reduced and the inference process is sped up significantly. Finally, with so-called On-The-Fly Markets, we present a motivation and an application of our approach where such knowledge is available.
AU - Wever, Marcel Dominik
AU - van Rooijen, Lorijn
AU - Hamann, Heiko
ID - 15025
JF - Evolutionary Computation
TI - Multi-Oracle Coevolutionary Learning of Requirements Specifications from Examples in On-The-Fly Markets
ER -
TY - CONF
AU - Meyer auf der Heide, Friedhelm
AU - Schaefer, Johannes Sebastian
ID - 7570
SN - 9781450357999
T2 - Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA '18
TI - Brief Announcement: Communication in Systems of Home Based Mobile Agents
ER -
TY - GEN
AU - Kolpaczki, Patrick Irenäus
ID - 5404
TI - Online Algorithmen für das k-Page Migration Problem
ER -
TY - JOUR
AB - Software Defined Networks (SDN) and Network Function Virtualisation (NFV) provide the basis for autonomous response and mitigation against attacks on networked computer infrastructures. We propose a new framework that uses SDNs and NFV to achieve this goal: Secure Autonomous Response Network (SARNET). In a SARNET, an agent running a control loop constantly assesses the security state of the network by means of observables. The agent reacts to and resolves security problems, while learning from its previous decisions. Two main metrics govern the decision process in a SARNET: impact and efficiency; these metrics can be used to compare and evaluate countermeasures and are the building blocks for self-learning SARNETs that exhibit autonomous response. In this paper we present the software implementation of the SARNET framework, evaluate it in a real-life network and discuss the tradeoffs between parameters used by the SARNET agent and the efficiency of its actions.
AU - Koning, R.
AU - de Graaff, B.
AU - Polevoy, Gleb
AU - Meijer, R.
AU - de Laat, C.
AU - Grosso, P.
ID - 17666
JF - Future Generation Computer Systems
KW - Software defined networks
KW - Network function virtualization
KW - Cyber attacks
KW - Cyber security
KW - Defense efficiency
KW - Overlay networks
SN - 0167-739X
TI - Measuring the efficiency of SDN mitigations against attacks on computer infrastructures
ER -
TY - GEN
AU - Kemper, Arne
ID - 1186
TI - Pure Nash Equilibria in Robust Congestion Games via Potential Functions
ER -
TY - JOUR
AB - In budget games, players compete over resources with finite budgets. For every resource, a player has a specific demand and as a strategy, he chooses a subset of resources. If the total demand on a resource does not exceed its budget, the utility of each player who chose that resource equals his demand. Otherwise, the budget is shared proportionally. In the general case, pure Nash equilibria (NE) do not exist for such games. In this paper, we consider the natural classes of singleton and matroid budget games with additional constraints and show that for each, pure NE can be guaranteed. In addition, we introduce a lexicographical potential function to prove that every matroid budget game has an approximate pure NE which depends on the largest ratio between the different demands of each individual player.
AU - Drees, Maximilian
AU - Feldotto, Matthias
AU - Riechers, Sören
AU - Skopalik, Alexander
ID - 1369
JF - Journal of Combinatorial Optimization
SN - 1382-6905
TI - Pure Nash equilibria in restricted budget games
ER -
TY - CHAP
AU - Feldkord, Björn
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
ID - 16392
SN - 0302-9743
T2 - Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications
TI - A Dynamic Distributed Data Structure for Top-k and k-Select Queries
ER -
TY - CONF
AB - We consider a market where final products or services are compositions of a number of basic services. Users are asked to evaluate the quality of the composed product after purchase. The quality of the basic service influences the performance of the composed services but cannot be observed directly. The question we pose is whether it is possible to use user evaluations on composed services to assess the quality of basic services. We discuss how to combine aggregation of evaluations across users and disaggregation of information on composed services to derive valuations for the single components. As a solution we propose to use the (weighted) average as aggregation device in connection with the Shapley value as disaggregation method, since this combination fulfills natural requirements in our context. In addition, we address some occurring computational issues: We give an approximate solution concept using only a limited number of evaluations which guarantees nearly optimal results with reduced running time. Lastly, we show that a slightly modified Shapley value and the weighted average are still applicable if the evaluation profiles are incomplete.
AU - Feldotto, Matthias
AU - Haake, Claus-Jochen
AU - Skopalik, Alexander
AU - Stroh-Maraun, Nadja
ID - 2831
SN - 978-1-4503-5916-0
T2 - Proceedings of the 13th Workshop on Economics of Networks, Systems and Computation (NetEcon 2018)
TI - Disaggregating User Evaluations Using the Shapley Value
ER -
TY - JOUR
AU - Li, Shouwei
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
ID - 2848
IS - 5
JF - Algorithmica
TI - Towards Flexible Demands in Online Leasing Problems.
VL - 80
ER -
TY - CONF
AB - We present a peer-to-peer network that supports the efficient processing of orthogonal range queries $R=\bigtimes_{i=1}^{d}[a_i,\,b_i]$ in a $d$-dimensional point space.\\
The network is the same for each dimension, namely a distance halving network like the one introduced by Naor and Wieder (ACM TALG'07).
We show how to execute such range queries using $\mathcal{O}\left(2^{d'}d\,\log m + d\,|R|\right)$ hops (and the same number of messages) in total. Here $[m]^d$ is the ground set, $|R|$ is the size and $d'$ the dimension of the queried range.
Furthermore, if the peers form a distributed network, the query can be answered in $\mathcal{O}\left(d\,\log m + d\,\sum_{i=1}^{d}(b_i-a_i+1)\right)$ communication rounds.
Our algorithms are based on a mapping of the Hilbert Curve through $[m]^d$ to the peers.
AU - Benter, Markus
AU - Knollmann, Till
AU - Meyer auf der Heide, Friedhelm
AU - Setzer, Alexander
AU - Sundermeier, Jannik
ID - 4375
KW - Distributed Storage
KW - Multi-Dimensional Range Queries
KW - Peer-to-Peer
KW - Hilbert Curve
T2 - Proceedings of the 4th International Symposium on Algorithmic Aspects of Cloud Computing (ALGOCLOUD)
TI - A Peer-to-Peer based Cloud Storage supporting orthogonal Range Queries of arbitrary Dimension
ER -
TY - CONF
AU - Hamann, Heiko
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
AU - Wahby, Mostafa
ID - 2850
T2 - Ninth International Conference on Fun with Algorithms (FUN)
TI - Pick, Pack, & Survive: Charging Robots in a Modern Warehouse based on Online Connected Dominating Sets
ER -
TY - GEN
AB - We introduce the \emph{Online Connected Dominating Set Leasing} problem
(OCDSL) in which we are given an undirected connected graph $G = (V, E)$, a set
$\mathcal{L}$ of lease types each characterized by a duration and cost, and a
sequence of subsets of $V$ arriving over time. A node can be leased using lease
type $l$ for cost $c_l$ and remains active for time $d_l$. The adversary gives
in each step $t$ a subset of nodes that need to be dominated by a connected
subgraph consisting of nodes active at time $t$. The goal is to minimize the
total leasing costs. OCDSL contains the \emph{Parking Permit
Problem}~\cite{PPP} as a special subcase and generalizes the classical offline
\emph{Connected Dominating Set} problem~\cite{Guha1998}. It has an $\Omega(\log
^2 n + \log |\mathcal{L}|)$ randomized lower bound resulting from lower bounds
for the \emph{Parking Permit Problem} and the \emph{Online Set Cover}
problem~\cite{Alon:2003:OSC:780542.780558,Korman}, where $|\mathcal{L}|$ is the
number of available lease types and $n$ is the number of nodes in the input
graph. We give a randomized $\mathcal{O}(\log ^2 n + \log |\mathcal{L}| \log
n)$-competitive algorithm for OCDSL. We also give a deterministic algorithm for
a variant of OCDSL in which the dominating subgraph need not be connected, the
\emph{Online Dominating Set Leasing} problem. The latter is based on a simple
primal-dual approach and has an $\mathcal{O}(|\mathcal{L}| \cdot
\Delta)$-competitive ratio, where $\Delta$ is the maximum degree of the input
graph.
AU - Markarian, Christine
ID - 19978
T2 - arXiv:1805.02994
TI - Online Connected Dominating Set Leasing
ER -
TY - CONF
AU - Jung, Daniel
AU - Kolb, Christina
AU - Scheideler, Christian
AU - Sundermeier, Jannik
ID - 4565
SN - 9781450357999
T2 - Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures (SPAA)
TI - Brief Announcement: Competitive Routing in Hybrid Communication Networks
ER -
TY - GEN
AU - Nachtigall, Marcel
ID - 1187
TI - Scenario-driven Strategy Analysis in a n-player Composition Game Model
ER -
TY - JOUR
AU - Abu-Khzam, Faisal N.
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
AU - Schubert, Michael
ID - 2849
JF - Theory of Computing Systems
TI - Approximation and Heuristic Algorithms for Computing Backbones in Asymmetric Ad-hoc Networks
ER -
TY - JOUR
AU - König, Jürgen
AU - Mäcker, Alexander
AU - Meyer auf der Heide, Friedhelm
AU - Riechers, Sören
ID - 3551
IS - 4
JF - Journal of Combinatorial Optimization
TI - Scheduling with interjob communication on parallel processors
VL - 36
ER -
TY - JOUR
AB - We study a new class of games which generalizes congestion games andits bottleneck variant. We introduce congestion games with mixed objectives to modelnetwork scenarios in which players seek to optimize for latency and bandwidths alike.We characterize the (non-)existence of pure Nash equilibria (PNE), the convergenceof improvement dynamics, the quality of equilibria and show the complexity of thedecision problem. For games that do not possess PNE we give bounds on the approx-imation ratio of approximate pure Nash equilibria.
AU - Feldotto, Matthias
AU - Leder, Lennart
AU - Skopalik, Alexander
ID - 669
IS - 4
JF - Journal of Combinatorial Optimization
SN - 1382-6905
TI - Congestion games with mixed objectives
VL - 36
ER -
TY - JOUR
AU - Althaus, Ernst
AU - Brinkmann, Andre
AU - Kling, Peter
AU - Meyer auf der Heide, Friedhelm
AU - Nagel, Lars
AU - Riechers, Sören
AU - Sgall, Jiri
AU - Süß, Tim
ID - 63
IS - 1
JF - Journal of Scheduling
TI - Scheduling Shared Continuous Resources on Many-Cores
VL - 21
ER -
TY - CONF
AB - Consider mitigating the effects of denial of service or of malicious traffic in networks by deleting edges. Edge deletion reduces the DoS or the number of the malicious flows, but it also inadvertently removes some of the desired flows. To model this important problem, we formulate two problems: (1) remove all the undesirable flows while minimizing the damage to the desirable ones and (2) balance removing the undesirable flows and not removing too many of the desirable flows. We prove these problems are equivalent to important theoretical problems, thereby being important not only practically but also theoretically, and very hard to approximate in a general network. We employ reductions to nonetheless approximate the problem and also provide a greedy approximation. When the network is a tree, the problems are still MAX SNP-hard, but we provide a greedy-based 2l-approximation algorithm, where l is the longest desirable flow. We also provide an algorithm, approximating the first and the second problem within {\$}{\$}2 {\backslash}sqrt{\{} 2{\backslash}left| E {\backslash}right| {\}}{\$}{\$}and {\$}{\$}2 {\backslash}sqrt{\{}2 ({\backslash}left| E {\backslash}right| + {\backslash}left| {\backslash}text {\{}undesirable flows{\}} {\backslash}right| ){\}}{\$}{\$}, respectively, where E is the set of the edges of the network. We also provide a fixed-parameter tractable (FPT) algorithm. Finally, if the tree has a root such that every flow in the tree flows on the path from the root to a leaf, we solve the problem exactly using dynamic programming.
AU - Polevoy, Gleb
AU - Trajanovski, Stojan
AU - Grosso, Paola
AU - de Laat, Cees
ED - Kim, Donghyun
ED - Uma, R. N.
ED - Zelikovsky, Alexander
ID - 17651
KW - flow
KW - Red-Blue Set Cover
KW - Positive-Negative Partial Set Cover
KW - approximation
KW - tree
KW - MAX SNP-hard
KW - root
KW - leaf
KW - dynamic programming
KW - FPT
SN - 978-3-030-04651-4
T2 - Combinatorial Optimization and Applications
TI - Removing Undesirable Flows by Edge Deletion
ER -