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 - 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 - 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 - GEN
AU - Kempf, Jérôme
ID - 1188
TI - Learning deterministic bandit behaviour form compositions
ER -
TY - CONF
AB - We study the classic bin packing problem in a fully-dynamic setting, where new items can arrive and old items may depart. We want algorithms with low asymptotic competitive ratio while repacking items sparingly between updates. Formally, each item i has a movement cost c_i >= 0, and we want to use alpha * OPT bins and incur a movement cost gamma * c_i, either in the worst case, or in an amortized sense, for alpha, gamma as small as possible. We call gamma the recourse of the algorithm. This is motivated by cloud storage applications, where fully-dynamic bin packing models the problem of data backup to minimize the number of disks used, as well as communication incurred in moving file backups between disks. Since the set of files changes over time, we could recompute a solution periodically from scratch, but this would give a high number of disk rewrites, incurring a high energy cost and possible wear and tear of the disks. In this work, we present optimal tradeoffs between number of bins used and number of items repacked, as well as natural extensions of the latter measure.
AU - Feldkord, Björn
AU - Feldotto, Matthias
AU - Gupta, Anupam
AU - Guruganesh, Guru
AU - Kumar, Amit
AU - Riechers, Sören
AU - Wajc, David
ED - Chatzigiannakis, Ioannis
ED - Kaklamanis, Christos
ED - Marx, Dániel
ED - Sannella, Donald
ID - 2484
SN - 1868-8969
T2 - 45th International Colloquium on Automata, Languages, and Programming (ICALP 2018)
TI - Fully-Dynamic Bin Packing with Little Repacking
VL - 107
ER -
TY - CONF
AB - While a lot of 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.
Considering crashing peers in peer-to-peer networks, it should not be taken for granted that a distributed data structure remains intact.
In this work, 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 a wide area of applications including string matching problems 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 $\mathcal{O}(\log |x|)$ hash table read accesses.
We show how to maintain the structure in a self-stabilizing way.
Our protocol assures low overhead in a legal state and a total (asymptotically optimal) memory demand of $\Theta(d)$ bits, where $d$ is the number of bits needed for storing all keys.
AU - Knollmann, Till
AU - Scheideler, Christian
ED - Izumi, Taisuke
ED - Kuznetsov, Petr
ID - 4411
KW - Self-Stabilizing
KW - Prefix Search
KW - Distributed Data Structure
T2 - Proceedings of the 20th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)
TI - A Self-Stabilizing Hashed Patricia Trie
VL - 11201
ER -
TY - THES
AU - Jung, Daniel
ID - 1209
TI - Local Strategies for Swarm Formations on a Grid
ER -
TY - CONF
AU - Feldkord, Björn
AU - Meyer auf der Heide, Friedhelm
ID - 2485
T2 - Proceedings of the 30th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)
TI - Online Facility Location with Mobile Facilities
ER -
TY - GEN
AU - Koop, Samuel
ID - 3851
TI - Congestion Games mit gewichteten Strategien
ER -
TY - CONF
AB - Routing is a challenging problem for wireless ad hoc networks, especially when the nodes are mobile and spread so widely that in most cases multiple hops are needed to route a message from one node to another. In fact, it is known that any online routing protocol has a poor performance in the worst case, in a sense that there is a distribution of nodes resulting in bad routing paths for that protocol, even if the nodes know their geographic positions and the geographic position of the destination of a message is known. The reason for that is that radio holes in the ad hoc network may require messages to take long detours in order to get to a destination, which are hard to find in an online fashion.
In this paper, we assume that the wireless ad hoc network can make limited use of long-range links provided by a global communication infrastructure like a cellular infrastructure or a satellite in order to compute an abstraction of the wireless ad hoc network that allows the messages to be sent along near-shortest paths in the ad hoc network. We present distributed algorithms that compute an abstraction of the ad hoc network in $\mathcal{O}\left(\log ^2 n\right)$ time using long-range links, which results in $c$-competitive routing paths between any two nodes of the ad hoc network for some constant $c$ if the convex hulls of the radio holes do not intersect. We also show that the storage needed for the abstraction just depends on the number and size of the radio holes in the wireless ad hoc network and is independent on the total number of nodes, and this information just has to be known to a few nodes for the routing to work.
AU - Jung, Daniel
AU - Kolb, Christina
AU - Scheideler, Christian
AU - Sundermeier, Jannik
ID - 4563
KW - greedy routing
KW - ad hoc networks
KW - convex hulls
KW - c-competitiveness
T2 - Proceedings of the 14th International Symposium on Algorithms and Experiments for Wireless Networks (ALGOSENSORS)
TI - Competitive Routing in Hybrid Communication Networks
ER -
TY - GEN
AU - Geromel, Marcel
ID - 5403
TI - Mobile Facility Leasing
ER -
TY - CONF
AB - We study a model of selfish resource allocation that seeks to incorporate dependencies among resources as they exist in in modern networked environments. Our model is inspired by utility functions with constant elasticity of substitution (CES) which is a well-studied model in economics. We consider congestion games with different aggregation functions. In particular, we study $L_p$ norms and analyze the existence and complexity of (approximate) pure Nash equilibria. Additionally, we give an almost tight characterization based on monotonicity properties to describe the set of aggregation functions that guarantee the existence of pure Nash equilibria.
AU - Feldotto, Matthias
AU - Leder, Lennart
AU - Skopalik, Alexander
ID - 112
T2 - Proceedings of the 10th International Conference on Algorithms and Complexity (CIAC)
TI - Congestion Games with Complementarities
ER -
TY - CONF
AB - In der CAD-unterstützten Entwicklung von technischen Systemen (Maschinen, Anlagen etc.) werden virtuelle Prototypen im Rahmen eines virtuellen Design-Reviews mit Hilfe eines VR-Systems gesamtheitlich betrachtet, um frühzeitig Fehler und Verbesserungsbedarf zu erkennen. Ein wichtiger Untersuchungsgegenstand ist dabei die Analyse von Transportwegen für den Materialtransport mittels Fließbändern, Förderketten oder schienenbasierten Transportsystemen. Diese Transportwege werden im VR-System animiert. Problematisch dabei ist, dass derartige Transportsysteme im zugrundeliegenden CAD-Modell in der Praxis oft nicht modelliert und nur exemplarisch angedeutet werden, da diese für die Konstruktion nicht relevant sind (z.B. der Fördergurt eines Förderbandes, oder die Kette einer Förderkette), oder die Informationen über den Verlauf bei der Konvertierung der Daten in das VR-System verloren gehen. Bei der Animation dieser Transportsysteme in einem VR-System muss der Transportweg also aufwändig, manuell nachgearbeitet werden. Das Ziel dieser Arbeit ist die Reduzierung des notwendigen manuellen Nachbearbeitungsaufwandes für das Design-Review durch eine automatische Berechnung der Animationspfade entlang eines Transportsystems. Es wird ein Algorithmus vorgestellt, der es ermöglicht mit nur geringem zeitlichem Benutzeraufwand den Animationspfad aus den reinen polygonalen dreidimensionalen Daten eines Transportsystems automatisch zu rekonstruieren.
AU - Brandt, Sascha
AU - Fischer, Matthias
ID - 16339
T2 - Wissenschaftsforum Intelligente Technische Systeme (WInTeSys) 2017
TI - Automatische Ableitung der Transportwege von Transportsystemen aus dem 3D-Polygonmodell
VL - 369
ER -
TY - CONF
AB - We consider a scheduling problem on $m$ identical processors sharing an arbitrarily divisible resource. In addition to assigning jobs to processors, the scheduler must distribute the resource among the processors (e.g., for three processors in shares of 20\%, 15\%, and 65\%) and adjust this distribution over time. Each job $j$ comes with a size $p_j \in \mathbb{R}$ and a resource requirement $r_j > 0$. Jobs do not benefit when receiving a share larger than $r_j$ of the resource. But providing them with a fraction of the resource requirement causes a linear decrease in the processing efficiency. We seek a (non-preemptive) job and resource assignment minimizing the makespan.Our main result is an efficient approximation algorithm which achieves an approximation ratio of $2 + 1/(m-2)$. It can be improved to an (asymptotic) ratio of $1 + 1/(m-1)$ if all jobs have unit size. Our algorithms also imply new results for a well-known bin packing problem with splittable items and a restricted number of allowed item parts per bin.Based upon the above solution, we also derive an approximation algorithm with similar guarantees for a setting in which we introduce so-called tasks each containing several jobs and where we are interested in the average completion time of tasks (a task is completed when all its jobs are completed).
AU - Kling, Peter
AU - Mäcker, Alexander
AU - Riechers, Sören
AU - Skopalik, Alexander
ID - 59
T2 - Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)
TI - Sharing is Caring: Multiprocessor Scheduling with a Sharable Resource
ER -
TY - CONF
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 - 66
T2 - Proceedings of the 23rd International Computing and Combinatorics Conference (COCOON)
TI - Pure Nash Equilibria in Restricted Budget Games
ER -
TY - JOUR
AU - Mäcker, Alexander
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
AU - Riechers, Sören
ID - 706
IS - 4
JF - Journal of Combinatorial Optimization
TI - Cost-efficient Scheduling on Machines from the Cloud
VL - 36
ER -
TY - CHAP
AU - Bemmann, Pascal
AU - Biermeier, Felix
AU - Bürmann, Jan
AU - Kemper, Arne
AU - Knollmann, Till
AU - Knorr, Steffen
AU - Kothe, Nils
AU - Mäcker, Alexander
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
AU - Riechers, Sören
AU - Schaefer, Johannes
AU - Sundermeier, Jannik
ID - 16461
SN - 0302-9743
T2 - Structural Information and Communication Complexity
TI - Monitoring of Domain-Related Problems in Distributed Data Streams
ER -
TY - GEN
AU - Bürmann, Jan
ID - 1080
TI - Complexity of Signalling in Routing Games under Uncertainty
ER -
TY - GEN
AU - Nachtigall, Simon
ID - 1073
TI - Sortieren dynamischer Daten
ER -
TY - CONF
AB - We study the computation of approximate pure Nash equilibria in Shapley value (SV) weighted congestion games, introduced in [19]. This class of games considers weighted congestion games in which Shapley values are used as an alternative (to proportional shares) for distributing the total cost of each resource among its users. We focus on the interesting subclass of such games with polynomial resource cost functions and present an algorithm that computes approximate pure Nash equilibria with a polynomial number of strategy updates. Since computing a single strategy update is hard, we apply sampling techniques which allow us to achieve polynomial running time. The algorithm builds on the algorithmic ideas of [7], however, to the best of our knowledge, this is the first algorithmic result on computation of approximate equilibria using other than proportional shares as player costs in this setting. We present a novel relation that approximates the Shapley value of a player by her proportional share and vice versa. As side results, we upper bound the approximate price of anarchy of such games and significantly improve the best known factor for computing approximate pure Nash equilibria in weighted congestion games of [7].
AU - Feldotto, Matthias
AU - Gairing, Martin
AU - Kotsialou, Grammateia
AU - Skopalik, Alexander
ID - 113
T2 - Proceedings of the 13th International Conference on Web and Internet Economics (WINE)
TI - Computing Approximate Pure Nash Equilibria in Shapley Value Weighted Congestion Games
ER -
TY - CONF
AU - Fischer, Matthias
AU - Jung, Daniel
AU - Meyer auf der Heide, Friedhelm
ED - Fernández Anta, Antonio
ED - Jurdzinski, Tomasz
ED - Mosteiro, Miguel A.
ED - Zhang, Yanyong
ID - 16347
T2 - Algorithms for Sensor Systems - 13th International Symposium on Algorithms and Experiments for Wireless Sensor Networks, {ALGOSENSORS}
TI - Gathering Anonymous, Oblivious Robots on a Grid
VL - 10718
ER -
TY - CONF
AB - We introduce the mobile server problem, inspired by current trends to move computational tasks from cloud structures to multiple devices close to the end user. An example for this are embedded systems in autonomous cars that communicate in order to coordinate their actions. Our model is a variant of the classical Page Migration Problem. Moreformally, we consider a mobile server holding a data page.The server can move in the Euclidean space (of arbitrary dimension). In every round, requests for data items from the page pop up at arbitrary points in the space. The requests are served, each at a cost of the distance from the requesting point and the server, and the mobile server may move, at a cost D times the distance traveled for some constant D . We assume a maximum distance m the server is allowed to move per round. We show that no online algorithm can achieve a competitive ratio independent of the length of the input sequence in this setting. Hence we augment the maximum movement distance of the online algorithms to ( 1 + δ) times the maximum distance of the offline solution. We provide a deterministic algorithm which is simple to describe and works for multiple variants of our problem. The algorithm achieves almost tight competitive ratios independent of the length of the input sequence.
AU - Feldkord, Björn
AU - Meyer auf der Heide, Friedhelm
ID - 55
T2 - Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA)
TI - The Mobile Server Problem
ER -
TY - CONF
AB - Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time.The machine requires a setup taking $s$ time units whenever it switches from processing jobs of one type to jobs of a different type.We consider the problem as an online problem where each job is only known to the scheduler as soon as it arrives and where the processing time of a job only becomes known upon its completion (non-clairvoyance).We are interested in the potential of simple ``greedy-like'' algorithms.We analyze a modification of the FIFO strategy and show its competitiveness to be $\Theta(\sqrt{n})$, which is optimal for the considered class of algorithms.For $k=2$ types it achieves a constant competitiveness.Our main insight is obtained by an analysis of the smoothed competitiveness.If processing times $p_j$ are independently perturbed to $\hat p_j = (1+X_j)p_j$, we obtain a competitiveness of $O(\sigma^{-2} \log^2 n)$ when $X_j$ is drawn from a uniform or a (truncated) normal distribution with standard deviation $\sigma$.The result proves that bad instances are fragile and ``practically'' one might expect a much better performance than given by the $\Omega(\sqrt{n})$-bound.
AU - Mäcker, Alexander
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
AU - Riechers, Sören
ID - 79
T2 - Proceedings of the 15th Workshop on Approximation and Online Algorithms (WAOA)
TI - Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup Times
VL - 10787
ER -
TY - GEN
AU - Vijayalakshmi, Vipin Ravindran
ID - 1081
TI - Bounding the Inefficiency of Equilibria in Congestion Games under Taxation
ER -
TY - GEN
AU - Pukrop, Simon
ID - 1074
TI - Robuste Optimierung in Congestion Games
ER -
TY - CONF
AU - Biermeier, Felix
AU - Feldkord, Björn
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
ID - 16348
T2 - Proceedings of the 15th Workshop on Approximation and Online Algorithms (WAOA)
TI - A Communication-Efficient Distributed Data Structure for Top-k and k-Select Queries
ER -
TY - CONF
AU - Markarian, Christine
ID - 2851
T2 - International Conference on Operations Research (OR)
TI - Leasing with Uncertainty
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 - Suess, Tim
ID - 63
JF - Journal of Scheduling
TI - Scheduling Shared Continuous Resources on Many-Cores
ER -
TY - GEN
AU - Nowack, Joshua
ID - 695
TI - On-The-Fly Konstruktion zusammenhängender Straßennetze aus gegebenen Einzelteilen
ER -
TY - CONF
AU - Feldkord, Björn
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
ID - 70
T2 - Proceedings of the 11th Annual International Conference on Combinatorial Optimization and Applications (COCOA)
TI - Price Fluctuations in Online Leasing
ER -
TY - THES
AU - Podlipyan, Pavel
ID - 703
TI - Local Algorithms for the Continuous Gathering Problem
ER -
TY - CONF
AB - Many graph problems such as maximum cut, chromatic number, hamiltonian cycle, and edge dominating set are known to be fixed-parameter tractable (FPT) when parameterized by the treewidth of the input graphs, but become W-hard with respect to the clique-width parameter. Recently, Gajarský et al. proposed a new parameter called modular-width using the notion of modular decomposition of graphs. They showed that the chromatic number problem and the partitioning into paths problem, and hence hamiltonian path and hamiltonian cycle, are FPT when parameterized by this parameter. In this paper, we study modular-width in parameterized parallel complexity and show that the weighted maximum clique problem and the maximum matching problem are fixed-parameter parallel-tractable (FPPT) when parameterized by this parameter.
AU - Abu-Khzam, Faisal N.
AU - Li, Shouwei
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
AU - Podlipyan, Pavel
ID - 82
T2 - Proceedings of the 11th International Workshop on Frontiers in Algorithmics (FAW)
TI - Modular-Width: An Auxiliary Parameter for Parameterized Parallel Complexity
ER -
TY - BOOK
AU - Gausemeier, Jürgen
AU - Bodden, Eric
AU - Dressler, Falko
AU - Dumitrescu, Roman
AU - Meyer auf der Heide, Friedhelm
AU - Scheytt, Christoph
AU - Trächtler, Ansgar
ID - 16444
TI - Wissenschaftsforum Intelligente Technische Systeme (WInTeSys)
ER -
TY - JOUR
AB - We consider an extension of the dynamic speed scaling scheduling model introduced by Yao et al.: A set of jobs, each with a release time, deadline, and workload, has to be scheduled on a single, speed-scalable processor. Both the maximum allowed speed of the processor and the energy costs may vary continuously over time. The objective is to find a feasible schedule that minimizes the total energy costs. Theoretical algorithm design for speed scaling problems often tends to discretize problems, as our tools in the discrete realm are often better developed or understood. Using the above speed scaling variant with variable, continuous maximal processor speeds and energy prices as an example, we demonstrate that a more direct approach via tools from variational calculus can not only lead to a very concise and elegant formulation and analysis, but also avoids the “explosion of variables/constraints” that often comes with discretizing. Using well-known tools from calculus of variations, we derive combinatorial optimality characteristics for our continuous problem and provide a quite concise and simple correctness proof.
AU - Antoniadis, Antonios
AU - Kling, Peter
AU - Ott, Sebastian
AU - Riechers, Sören
ID - 110
JF - Theoretical Computer Science
TI - Continuous Speed Scaling with Variability: A Simple and Direct Approach
ER -
TY - CONF
AB - Many university students struggle with motivational problems, and gamification has the potential to address these problems. However, gamification is hardly used in education, because current approaches to gamification require instructors to engage in the time-consuming preparation of their course contents for use in quizzes, mini-games and the like. Drawing on research on limited attention and present bias, we propose a "lean" approach to gamification, which relies on gamifying learning activities (rather than learning contents) and increasing their salience. In this paper, we present the app StudyNow that implements such a lean gamification approach. With this app, we aim to enable more students and instructors to benefit from the advantages of gamification.
AU - Feldotto, Matthias
AU - John, Thomas
AU - Kundisch, Dennis
AU - Hemsen, Paul
AU - Klingsieck, Katrin
AU - Skopalik, Alexander
ID - 1094
T2 - Proceedings of the 12th International Conference on Design Science Research in Information Systems and Technology (DESRIST)
TI - Making Gamification Easy for the Professor: Decoupling Game and Content with the StudyNow Mobile App
ER -
TY - CONF
AU - Podlipyan, Pavel
AU - Li, Shouwei
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
ID - 16349
T2 - Proceedings of the 13th International Symposium on Algorithms and Experiments for Wireless Networks (ALGOSENSORS)
TI - A Continuous Strategy for Collisionless Gathering
ER -
TY - THES
AU - Riechers, Sören
ID - 704
TI - Scheduling with Scarce Resources
ER -
TY - GEN
AB - We consider a swarm of $n$ autonomous mobile robots, distributed on a
2-dimensional grid. A basic task for such a swarm is the gathering process: All
robots have to gather at one (not predefined) place. A common local model for
extremely simple robots is the following: The robots do not have a common
compass, only have a constant viewing radius, are autonomous and
indistinguishable, can move at most a constant distance in each step, cannot
communicate, are oblivious and do not have flags or states. The only gathering
algorithm under this robot model, with known runtime bounds, needs
$\mathcal{O}(n^2)$ rounds and works in the Euclidean plane. The underlying time
model for the algorithm is the fully synchronous $\mathcal{FSYNC}$ model. On
the other side, in the case of the 2-dimensional grid, the only known gathering
algorithms for the same time and a similar local model additionally require a
constant memory, states and "flags" to communicate these states to neighbors in
viewing range. They gather in time $\mathcal{O}(n)$.
In this paper we contribute the (to the best of our knowledge) first
gathering algorithm on the grid that works under the same simple local model as
the above mentioned Euclidean plane strategy, i.e., without memory (oblivious),
"flags" and states. We prove its correctness and an $\mathcal{O}(n^2)$ time
bound in the fully synchronous $\mathcal{FSYNC}$ time model. This time bound
matches the time bound of the best known algorithm for the Euclidean plane
mentioned above. We say gathering is done if all robots are located within a
$2\times 2$ square, because in $\mathcal{FSYNC}$ such configurations cannot be
solved.
AU - Fischer, Matthias
AU - Jung, Daniel
AU - Meyer auf der Heide, Friedhelm
ID - 17811
T2 - arXiv:1702.03400
TI - Gathering Anonymous, Oblivious Robots on a Grid
ER -
TY - CONF
AB - Many university students struggle with motivational problems, and gamification has the potential to address these problems. However, using gamification currently is rather tedious and time-consuming for instructors because current approaches to gamification require instructors to engage in the time-consuming preparation of course contents (e.g., for quizzes or mini-games). In reply to this issue, we propose a “lean” approach to gamification, which relies on gamifying learning activities rather than learning contents. The learning activities that are gamified in the lean approach can typically be drawn from existing course syllabi (e.g., attend certain lectures, hand in assignments, read book chapters and articles). Hence, compared to existing approaches, lean gamification substantially lowers the time requirements posed on instructors for gamifying a given course. Drawing on research on limited attention and the present bias, we provide the theoretical foundation for the lean gamification approach. In addition, we present a mobile application that implements lean gamification and outline a mixed-methods study that is currently under way for evaluating whether lean gamification does indeed have the potential to increase students’ motivation. We thereby hope to allow more students and instructors to benefit from the advantages of gamification.
AU - John, Thomas
AU - Feldotto, Matthias
AU - Hemsen, Paul
AU - Klingsieck, Katrin
AU - Kundisch, Dennis
AU - Langendorf, Mike
ID - 1095
T2 - Proceedings of the 25th European Conference on Information Systems (ECIS)
TI - Towards a Lean Approach for Gamifying Education
ER -
TY - CONF
AB - To detect errors or find potential for improvement during the CAD-supported development of a complex technical system like modern industrial machines, the system’s virtual prototype can be examined in virtual reality (VR) in the context of virtual design reviews. Besides exploring the static shape of the examined system, observing the machines’ mechanics (e.g., motor-driven mechanisms) and transport routes for the material transport (e.g., via conveyor belts or chains, or rail-based transport systems) can play an equally important role in such a review. In practice it is often the case, that the relevant information about transport routes, or kinematic properties is either not consequently modeled in the CAD data or is lost during conversion processes. To significantly reduce the manual effort and costs for creating animations of the machines complex behavior with such limited input data for a design review, we present a set of algorithms to automatically determine geometrical properties of machine parts based only on their triangulated surfaces. The algorithms allow to detect the course of transport systems, the orientation of objects in 3d space, rotation axes of cylindrical objects and holes, the number of tooth of gears, as well as the tooth spacing of toothed racks. We implemented the algorithms in the VR system PADrend and applied them to animate virtual prototypes of real machines.
AU - Brandt, Sascha
AU - Fischer, Matthias
AU - Gerges, Maria
AU - Jähn, Claudius
AU - Berssenbrügge, Jan
ID - 16338
SN - 9780791858110
T2 - Volume 1: 37th Computers and Information in Engineering Conference
TI - Automatic Derivation of Geometric Properties of Components From 3D Polygon Models
VL - 1
ER -
TY - CONF
AB - We present an efficient parallel algorithm for the general Monotone Circuit Value Problem (MCVP) with n gates and an underlying graph of bounded genus k. Our algorithm generalizes a recent result by Limaye et al. who showed that MCVP with toroidal embedding (genus 1) is in NC when the input contains a toroidal embedding of the circuit. In addition to extending this result from genus 1 to any bounded genus k, and unlike the work reported by Limaye et al., we do not require a precomputed embedding to be given. Most importantly, our results imply that given a P-complete problem, it is possible to find an algorithm that makes the problem fall into NC by fixing one or more parameters. Hence, we deduce the interesting analogy: Fixed Parameter Parallelizable (FPP) is with respect to P-complete what Fixed Parameter Tractable (FPT) is with respect to NP-complete. Similar work that uses treewidth as parameter was also presented by Elberfeld et al. in [6].
AU - Abu-Khzam, Faisal N.
AU - Li, Shouwei
AU - Markarian, Christine
AU - Meyer auf der Heide, Friedhelm
AU - Podlipyan, Pavel
ID - 143
T2 - Proceedings of the 22nd International Conference on Computing and Combinatorics (COCOON)
TI - The Monotone Circuit Value Problem with Bounded Genus Is in NC
ER -
TY - CONF
AU - Li, Shouwei
AU - Meyer auf der Heide, Friedhelm
AU - Podlipyan, Pavel
ID - 16358
T2 - Algorithms for Sensor Systems, Proceedings of the 12th International Symposium on Algorithms and Experiments for Wireless Sensor Networks (ALGOSENSORS)
TI - The impact of the Gabriel subgraph of the visibility graph on the gathering of mobile autonomous robots
ER -
TY - CONF
AU - Abshoff, Sebastian
AU - Cord-Landwehr, Andreas
AU - Fischer, Matthias
AU - Jung, Daniel
AU - Meyer auf der Heide, Friedhelm
ID - 16360
T2 - Proceedings of the 30th International Parallel and Distributed Processing Symposium (IPDPS)
TI - Gathering a Closed Chain of Robots on a Grid
ER -
TY - GEN
AB - We consider a scheduling problem where machines need to be rented from the
cloud in order to process jobs. There are two types of machines available which
can be rented for machine-type dependent prices and for arbitrary durations.
However, a machine-type dependent setup time is required before a machine is
available for processing. Jobs arrive online over time, have machine-type
dependent sizes and have individual deadlines. The objective is to rent
machines and schedule jobs so as to meet all deadlines while minimizing the
rental cost.
Since we observe the slack of jobs to have a fundamental influence on the
competitiveness, we study the model when instances are parameterized by their
(minimum) slack. An instance is called to have a slack of $\beta$ if, for all
jobs, the difference between the job's release time and the latest point in
time at which it needs to be started is at least $\beta$. While for $\beta < s$
no finite competitiveness is possible, our main result is an
$O(\frac{c}{\varepsilon} + \frac{1}{\varepsilon^3})$-competitive online
algorithm for $\beta = (1+\varepsilon)s$ with $\frac{1}{s} \leq \varepsilon
\leq 1$, where $s$ and $c$ denotes the largest setup time and the cost ratio of
the machine-types, respectively. It is complemented by a lower bound of
$\Omega(\frac{c}{\varepsilon})$.
AU - Mäcker, Alexander
AU - Malatyali, Manuel
AU - Meyer auf der Heide, Friedhelm
AU - Riechers, Sören
ID - 16396
T2 - arXiv:1609.01184
TI - Cost-efficient Scheduling on Machines from the Cloud
ER -
TY - CONF
AB - In this paper we consider a strategic variant of the online facility location problem. Given is a graph in which each node serves two roles: it is a strategic client stating requests as well as a potential location for a facility. In each time step one client states a request which induces private costs equal to the distance to the closest facility. Before serving, the clients may collectively decide to open new facilities, sharing the corresponding price. Instead of optimizing the global costs, each client acts selfishly. The prices of new facilities vary between nodes and also change over time, but are always bounded by some fixed value α. Both the requests as well as the facility prices are given by an online sequence and are not known in advance.We characterize the optimal strategies of the clients and analyze their overall performance in comparison to a centralized offline solution. If all players optimize their own competitiveness, the global performance of the system is O(√α⋅α) times worse than the offline optimum. A restriction to a natural subclass of strategies improves this result to O(α). We also show that for fixed facility costs, we can find strategies such that this bound further improves to O(√α).
AU - Drees, Maximilian
AU - Feldkord, Björn
AU - Skopalik, Alexander
ID - 149
T2 - Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA)
TI - Strategic Online Facility Location
ER -
TY - GEN
ED - Dressler, Falko
ED - Meyer auf der Heide, Friedhelm
ID - 163
TI - Proceedings of the 17th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc)
ER -