15 Search Results for "May, Patrick"

Document
Invited Paper
DOI: 10.4230/OASIcs.NG-RES.2024.1
HMB: Scheduling PREM-Like Real-Time Tasks at High Memory Bandwidth (Invited Paper)

Authors: Mohammadhassan Gholami Derouei, Paolo Valente, Marco Solieri, and Andrea Marongiu

Published in: OASIcs, Volume 117, Fifth Workshop on Next Generation Real-Time Embedded Systems (NG-RES 2024)

Abstract
Current homogeneous and heterogeneous computing systems reach high performance through parallelization. Yet, parallel execution of tasks entails non-trivial latency-vs-throughput issues when it comes to concurrent accesses to shared memory. In this respect, effective bandwidth regulation solutions do exist, and provide a basic mechanism to control the latency of memory accesses. Such solutions, though, are often cumbersome to deploy and to configure to guarantee both bounded latency and high utilization of the memory bandwidth. The problem is that memory latency varies non-linearly with the number and type of concurrent accesses, and the latter may in turn vary with time, often unpredictably. For this reason, previous attempts at memory regulation in scheduling solutions resulted either in poor real-time execution guarantees, or in severe underutilization of the memory bandwidth. In this paper, we outline High Memory Bandwidth (HMB), a scheduling solution that guarantees bounded response times to real-time task sets through memory regulation, while also reaching a high utilization memory bandwidth. Since the complete solution is complex, just like the problem it addresses, this preliminary work defines in full detail only the core mechanism. This mechanism builds on the notion of memory access slowdown experienced by any processor performing back-to-back memory operations; this slowdown is due to the interference generated by other processors also accessing the memory at the same time. The core mechanism assumes that each processor can tolerate a certain amount of slowdown before the timing behavior of the task(s) it is running is compromised. Each processor has a priority assigned: the higher the priority, the more stringent the timing requirements. The slowdown can be controlled by regulating with precision the maximum amount of system bandwidth each processor is allowed to use, based on its priority. The proposed mechanism finds the maximum bandwidth each processor can use such that the highest number of processors simultaneously accessing memory is found (thus avoiding memory bandwidth underutilization) while guaranteeing that the slowdown of each processor is kept within the tolerated limits.
Cite as

Mohammadhassan Gholami Derouei, Paolo Valente, Marco Solieri, and Andrea Marongiu. HMB: Scheduling PREM-Like Real-Time Tasks at High Memory Bandwidth (Invited Paper). In Fifth Workshop on Next Generation Real-Time Embedded Systems (NG-RES 2024). Open Access Series in Informatics (OASIcs), Volume 117, pp. 1:1-1:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{gholamiderouei_et_al:OASIcs.NG-RES.2024.1,
  author =	{Gholami Derouei, Mohammadhassan and Valente, Paolo and Solieri, Marco and Marongiu, Andrea},
  title =	{{HMB: Scheduling PREM-Like Real-Time Tasks at High Memory Bandwidth}},
  booktitle =	{Fifth Workshop on Next Generation Real-Time Embedded Systems (NG-RES 2024)},
  pages =	{1:1--1:18},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-313-3},
  ISSN =	{2190-6807},
  year =	{2024},
  volume =	{117},
  editor =	{Yomsi, Patrick Meumeu and Wildermann, Stefan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.NG-RES.2024.1},
  URN =		{urn:nbn:de:0030-drops-197049},
  doi =		{10.4230/OASIcs.NG-RES.2024.1},
  annote =	{Keywords: Heterogenous systems, Parallel execution, Shared memory, Bandwidth regulation, Memory access, Real-time execution, Memory bandwidth utilization, High Memory Bandwidth (HMB), Memory access slowdown, Memory interference, Memory-centric scheduling}
}
Document
RANDOM
DOI: 10.4230/LIPIcs.APPROX/RANDOM.2023.30
On Connectivity in Random Graph Models with Limited Dependencies

Authors: Johannes Lengler, Anders Martinsson, Kalina Petrova, Patrick Schnider, Raphael Steiner, Simon Weber, and Emo Welzl

Published in: LIPIcs, Volume 275, Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2023)

Abstract
For any positive edge density p, a random graph in the Erdős-Rényi G_{n,p} model is connected with non-zero probability, since all edges are mutually independent. We consider random graph models in which edges that do not share endpoints are independent while incident edges may be dependent and ask: what is the minimum probability ρ(n), such that for any distribution 𝒢 (in this model) on graphs with n vertices in which each potential edge has a marginal probability of being present at least ρ(n), a graph drawn from 𝒢 is connected with non-zero probability? As it turns out, the condition "edges that do not share endpoints are independent" needs to be clarified and the answer to the question above is sensitive to the specification. In fact, we formalize this intuitive description into a strict hierarchy of five independence conditions, which we show to have at least three different behaviors for the threshold ρ(n). For each condition, we provide upper and lower bounds for ρ(n). In the strongest condition, the coloring model (which includes, e.g., random geometric graphs), we show that ρ(n) → 2-ϕ ≈ 0.38 for n → ∞, proving a conjecture by Badakhshian, Falgas-Ravry, and Sharifzadeh. This separates the coloring models from the weaker independence conditions we consider, as there we prove that ρ(n) > 0.5-o(n). In stark contrast to the coloring model, for our weakest independence condition - pairwise independence of non-adjacent edges - we show that ρ(n) lies within O(1/n²) of the threshold 1-2/n for completely arbitrary distributions.
Cite as

Johannes Lengler, Anders Martinsson, Kalina Petrova, Patrick Schnider, Raphael Steiner, Simon Weber, and Emo Welzl. On Connectivity in Random Graph Models with Limited Dependencies. In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 275, pp. 30:1-30:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{lengler_et_al:LIPIcs.APPROX/RANDOM.2023.30,
  author =	{Lengler, Johannes and Martinsson, Anders and Petrova, Kalina and Schnider, Patrick and Steiner, Raphael and Weber, Simon and Welzl, Emo},
  title =	{{On Connectivity in Random Graph Models with Limited Dependencies}},
  booktitle =	{Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2023)},
  pages =	{30:1--30:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-296-9},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{275},
  editor =	{Megow, Nicole and Smith, Adam},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX/RANDOM.2023.30},
  URN =		{urn:nbn:de:0030-drops-188556},
  doi =		{10.4230/LIPIcs.APPROX/RANDOM.2023.30},
  annote =	{Keywords: Random Graphs, Independence, Dependency, Connectivity, Threshold, Probabilistic Method}
}
Document
DOI: 10.4230/LIPIcs.SAND.2022.10
Computing Outside the Box: Average Consensus over Dynamic Networks

Authors: Bernadette Charron-Bost and Patrick Lambein-Monette

Published in: LIPIcs, Volume 221, 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022)

Abstract
Networked systems of autonomous agents, and applications thereof, often rely on the control primitive of average consensus, where the agents are to compute the average of private initial values. To provide reliable services that are easy to deploy, average consensus should continue to operate when the network is subject to frequent and unpredictable change, and should mobilize few computational resources, so that deterministic, low powered, and anonymous agents can partake in the network. In this stringent adversarial context, we investigate the implementation of average consensus by distributed algorithms over networks with bidirectional, but potentially short-lived, communication links. Inspired by convex recurrence rules for multi-agent systems, and the Metropolis average consensus rule in particular, we design a deterministic distributed algorithm that achieves asymptotic average consensus, which we show to operate in polynomial time in a synchronous temporal model. The algorithm is easy to implement, has low space and computational complexity, and is fully distributed, requiring neither symmetry-breaking devices like unique identifiers, nor global control or knowledge of the network. In the fully decentralized model that we adopt, to our knowledge, no other distributed average consensus algorithm has a better temporal complexity. Our approach distinguishes itself from classical convex recurrence rules in that the agent’s values may sometimes leave their previous convex hull. As a consequence, our convergence bound requires a subtle analysis, despite the syntactic simplicity of our algorithm.
Cite as

Bernadette Charron-Bost and Patrick Lambein-Monette. Computing Outside the Box: Average Consensus over Dynamic Networks. In 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 221, pp. 10:1-10:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{charronbost_et_al:LIPIcs.SAND.2022.10,
  author =	{Charron-Bost, Bernadette and Lambein-Monette, Patrick},
  title =	{{Computing Outside the Box: Average Consensus over Dynamic Networks}},
  booktitle =	{1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022)},
  pages =	{10:1--10:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-224-2},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{221},
  editor =	{Aspnes, James and Michail, Othon},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.SAND.2022.10},
  URN =		{urn:nbn:de:0030-drops-159521},
  doi =		{10.4230/LIPIcs.SAND.2022.10},
  annote =	{Keywords: average consensus, dynamic networks, distributed algorithms, iterated averaging, Metropolis}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2020.39
Strategy Complexity of Parity Objectives in Countable MDPs

Authors: Stefan Kiefer, Richard Mayr, Mahsa Shirmohammadi, and Patrick Totzke

Published in: LIPIcs, Volume 171, 31st International Conference on Concurrency Theory (CONCUR 2020)

Abstract
We study countably infinite MDPs with parity objectives. Unlike in finite MDPs, optimal strategies need not exist, and may require infinite memory if they do. We provide a complete picture of the exact strategy complexity of ε-optimal strategies (and optimal strategies, where they exist) for all subclasses of parity objectives in the Mostowski hierarchy. Either MD-strategies, Markov strategies, or 1-bit Markov strategies are necessary and sufficient, depending on the number of colors, the branching degree of the MDP, and whether one considers ε-optimal or optimal strategies. In particular, 1-bit Markov strategies are necessary and sufficient for ε-optimal (resp. optimal) strategies for general parity objectives.
Cite as

Stefan Kiefer, Richard Mayr, Mahsa Shirmohammadi, and Patrick Totzke. Strategy Complexity of Parity Objectives in Countable MDPs. In 31st International Conference on Concurrency Theory (CONCUR 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 171, pp. 39:1-39:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{kiefer_et_al:LIPIcs.CONCUR.2020.39,
  author =	{Kiefer, Stefan and Mayr, Richard and Shirmohammadi, Mahsa and Totzke, Patrick},
  title =	{{Strategy Complexity of Parity Objectives in Countable MDPs}},
  booktitle =	{31st International Conference on Concurrency Theory (CONCUR 2020)},
  pages =	{39:1--39:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-160-3},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{171},
  editor =	{Konnov, Igor and Kov\'{a}cs, Laura},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2020.39},
  URN =		{urn:nbn:de:0030-drops-128513},
  doi =		{10.4230/LIPIcs.CONCUR.2020.39},
  annote =	{Keywords: Markov decision processes, Parity objectives, Levy’s zero-one law}
}
Document
Invited Talk
DOI: 10.4230/LIPIcs.ICALP.2020.3
How to Play in Infinite MDPs (Invited Talk)

Authors: Stefan Kiefer, Richard Mayr, Mahsa Shirmohammadi, Patrick Totzke, and Dominik Wojtczak

Published in: LIPIcs, Volume 168, 47th International Colloquium on Automata, Languages, and Programming (ICALP 2020)

Abstract
Markov decision processes (MDPs) are a standard model for dynamic systems that exhibit both stochastic and nondeterministic behavior. For MDPs with finite state space it is known that for a wide range of objectives there exist optimal strategies that are memoryless and deterministic. In contrast, if the state space is infinite, optimal strategies may not exist, and optimal or ε-optimal strategies may require (possibly infinite) memory. In this paper we consider qualitative objectives: reachability, safety, (co-)Büchi, and other parity objectives. We aim at giving an introduction to a collection of techniques that allow for the construction of strategies with little or no memory in countably infinite MDPs.
Cite as

Stefan Kiefer, Richard Mayr, Mahsa Shirmohammadi, Patrick Totzke, and Dominik Wojtczak. How to Play in Infinite MDPs (Invited Talk). In 47th International Colloquium on Automata, Languages, and Programming (ICALP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 168, pp. 3:1-3:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{kiefer_et_al:LIPIcs.ICALP.2020.3,
  author =	{Kiefer, Stefan and Mayr, Richard and Shirmohammadi, Mahsa and Totzke, Patrick and Wojtczak, Dominik},
  title =	{{How to Play in Infinite MDPs}},
  booktitle =	{47th International Colloquium on Automata, Languages, and Programming (ICALP 2020)},
  pages =	{3:1--3:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-138-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{168},
  editor =	{Czumaj, Artur and Dawar, Anuj and Merelli, Emanuela},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2020.3},
  URN =		{urn:nbn:de:0030-drops-124103},
  doi =		{10.4230/LIPIcs.ICALP.2020.3},
  annote =	{Keywords: Markov decision processes}
}
Document
DOI: 10.4230/LIPIcs.SWAT.2020.23
Trajectory Visibility

Authors: Patrick Eades, Ivor van der Hoog, Maarten Löffler, and Frank Staals

Published in: LIPIcs, Volume 162, 17th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2020)

Abstract
We study the problem of testing whether there exists a time at which two entities moving along different piece-wise linear trajectories among polygonal obstacles are mutually visible. We study several variants, depending on whether or not the obstacles form a simple polygon, trajectories may intersect the polygon edges, and both or only one of the entities are moving. For constant complexity trajectories contained in a simple polygon with n vertices, we provide an 𝒪(n) time algorithm to test if there is a time at which the entities can see each other. If the polygon contains holes, we present an 𝒪(n log n) algorithm. We show that this is tight. We then consider storing the obstacles in a data structure, such that queries consisting of two line segments can be efficiently answered. We show that for all variants it is possible to answer queries in sublinear time using polynomial space and preprocessing time. As a critical intermediate step, we provide an efficient solution to a problem of independent interest: preprocess a convex polygon such that we can efficiently test intersection with a quadratic curve segment. If the obstacles form a simple polygon, this allows us to answer visibility queries in 𝒪(n³/4log³ n) time using 𝒪(nlog⁵ n) space. For more general obstacles the query time is 𝒪(log^k n), for a constant but large value k, using 𝒪(n^{3k}) space. We provide more efficient solutions when one of the entities remains stationary.
Cite as

Patrick Eades, Ivor van der Hoog, Maarten Löffler, and Frank Staals. Trajectory Visibility. In 17th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 162, pp. 23:1-23:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{eades_et_al:LIPIcs.SWAT.2020.23,
  author =	{Eades, Patrick and van der Hoog, Ivor and L\"{o}ffler, Maarten and Staals, Frank},
  title =	{{Trajectory Visibility}},
  booktitle =	{17th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2020)},
  pages =	{23:1--23:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-150-4},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{162},
  editor =	{Albers, Susanne},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.SWAT.2020.23},
  URN =		{urn:nbn:de:0030-drops-122701},
  doi =		{10.4230/LIPIcs.SWAT.2020.23},
  annote =	{Keywords: trajectories, visibility, data structures, semi-algebraic range searching}
}
Document
DOI: 10.4230/DagRep.9.7.94
Secure Composition for Hardware Systems (Dagstuhl Seminar 19301)

Authors: Divya Arora, Ilia Polian, Francesco Regazzoni, and Patrick Schaumont

Published in: Dagstuhl Reports, Volume 9, Issue 7 (2020)

Abstract
The goal of the Dagstuhl Seminar 19301 ``Secure Composition for Hardware System'' was to establish a common understanding of principles and techniques that can facilitate composition and integration of hardware systems to achieve specified security guarantees. Theoretical foundations of secure composition have been laid out in the past, but they are limited to software systems. New and unique security challenges arise when a real system composed of a range of hardware components, including application-specific blocks, programmable microcontrollers, and reconfigurable fabrics, are put together. For example, these components may have different owners, different trust assumptions and may not even have a common language to describe their security properties to each other. Physical and side-channel attacks that take advantage of various physical properties to undermine a system's security objectives add another level of complexity to the secure composition problem. Moreover, practical hardware systems include software of tremendous size and complexity, and hardware-software interaction can create new security challenges. The seminar considered secure composition both from a pure hardware perspective, where multiple hardware blocks are composed in, e.g., a system on chip (SoC), and from a hardware-software perspective where hardware is integrated within a system that includes software. The seminar brought together researchers and industry practitioners from fields that have to deal with secure composition: Secure hardware architectures, hardware-oriented security, applied cryptography, test and verification of security properties. By involving industrial participants, we were able to get insights on real-world challenges, heuristics, and methodologies employed to address them and initiate a discussion towards new solutions.
Cite as

Divya Arora, Ilia Polian, Francesco Regazzoni, and Patrick Schaumont. Secure Composition for Hardware Systems (Dagstuhl Seminar 19301). In Dagstuhl Reports, Volume 9, Issue 7, pp. 94-116, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@Article{arora_et_al:DagRep.9.7.94,
  author =	{Arora, Divya and Polian, Ilia and Regazzoni, Francesco and Schaumont, Patrick},
  title =	{{Secure Composition for Hardware Systems (Dagstuhl Seminar 19301)}},
  pages =	{94--116},
  journal =	{Dagstuhl Reports},
  ISSN =	{2192-5283},
  year =	{2019},
  volume =	{9},
  number =	{7},
  editor =	{Arora, Divya and Polian, Ilia and Regazzoni, Francesco and Schaumont, Patrick},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagRep.9.7.94},
  URN =		{urn:nbn:de:0030-drops-116377},
  doi =		{10.4230/DagRep.9.7.94},
  annote =	{Keywords: Hardware, Secure composition, Security, Software}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2019.15
Timed Basic Parallel Processes

Authors: Lorenzo Clemente, Piotr Hofman, and Patrick Totzke

Published in: LIPIcs, Volume 140, 30th International Conference on Concurrency Theory (CONCUR 2019)

Abstract
Timed basic parallel processes (TBPP) extend communication-free Petri nets (aka. BPP or commutative context-free grammars) by a global notion of time. TBPP can be seen as an extension of timed automata (TA) with context-free branching rules, and as such may be used to model networks of independent timed automata with process creation. We show that the coverability and reachability problems (with unary encoded target multiplicities) are PSPACE-complete and EXPTIME-complete, respectively. For the special case of 1-clock TBPP, both are NP-complete and hence not more complex than for untimed BPP. This contrasts with known super-Ackermannian-completeness and undecidability results for general timed Petri nets. As a result of independent interest, and basis for our NP upper bounds, we show that the reachability relation of 1-clock TA can be expressed by a formula of polynomial size in the existential fragment of linear arithmetic, which improves on recent results from the literature.
Cite as

Lorenzo Clemente, Piotr Hofman, and Patrick Totzke. Timed Basic Parallel Processes. In 30th International Conference on Concurrency Theory (CONCUR 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 140, pp. 15:1-15:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{clemente_et_al:LIPIcs.CONCUR.2019.15,
  author =	{Clemente, Lorenzo and Hofman, Piotr and Totzke, Patrick},
  title =	{{Timed Basic Parallel Processes}},
  booktitle =	{30th International Conference on Concurrency Theory (CONCUR 2019)},
  pages =	{15:1--15:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-121-4},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{140},
  editor =	{Fokkink, Wan and van Glabbeek, Rob},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2019.15},
  URN =		{urn:nbn:de:0030-drops-109171},
  doi =		{10.4230/LIPIcs.CONCUR.2019.15},
  annote =	{Keywords: Timed Automata, Petri Nets}
}
Document
DOI: 10.4230/LIPIcs.STACS.2018.34
Dependences in Strategy Logic

Authors: Patrick Gardy, Patricia Bouyer, and Nicolas Markey

Published in: LIPIcs, Volume 96, 35th Symposium on Theoretical Aspects of Computer Science (STACS 2018)

Abstract
Strategy Logic (SL) is a very expressive temporal logic for specifying and verifying properties of multi-agent systems: in SL, one can quantify over strategies, assign them to agents, and express LTL properties of the resulting plays. Such a powerful framework has two drawbacks: First, model checking SL has non-elementary complexity; second, the exact semantics of SL is rather intricate, and may not correspond to what is expected. In this paper, we focus on strategy dependences in SL, by tracking how existentially-quantified strategies in a formula may (or may not) depend on other strategies selected in the formula, revisiting the approach of [Mogavero et al., Reasoning about strategies: On the model-checking problem, 2014]. We explain why elementary dependences, as defined by Mogavero et al., do not exactly capture the intended concept of behavioral strategies. We address this discrepancy by introducing timeline dependences, and exhibit a large fragment of SL for which model checking can be performed in 2-EXPTIME under this new semantics.
Cite as

Patrick Gardy, Patricia Bouyer, and Nicolas Markey. Dependences in Strategy Logic. In 35th Symposium on Theoretical Aspects of Computer Science (STACS 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 96, pp. 34:1-34:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@InProceedings{gardy_et_al:LIPIcs.STACS.2018.34,
  author =	{Gardy, Patrick and Bouyer, Patricia and Markey, Nicolas},
  title =	{{Dependences in Strategy Logic}},
  booktitle =	{35th Symposium on Theoretical Aspects of Computer Science (STACS 2018)},
  pages =	{34:1--34:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-062-0},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{96},
  editor =	{Niedermeier, Rolf and Vall\'{e}e, Brigitte},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2018.34},
  URN =		{urn:nbn:de:0030-drops-85320},
  doi =		{10.4230/LIPIcs.STACS.2018.34},
  annote =	{Keywords: strategic reasoning, strategy logic, dependences, behavioural strategies.}
}
Document
DOI: 10.4230/OASIcs.WCET.2016.6
The Variability of Application Execution Times on a Multi-Core Platform

Authors: Vincent Nélis, Patrick Meumeu Yomsi, and Luís Miguel Pinho

Published in: OASIcs, Volume 55, 16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016)

Abstract
It is a known fact that processes running concurrently on different cores in a multicore environment interfere with each other on the processor shared resources. The contention on these shared resources considerably slows down the execution on every core since sometimes the cores must stall while their requests to access the resources are being served. But by how much the execution may be slowed down due to this interference? In this paper we answer this question with numbers coming from experimentation. That is, we quantify the magnitude of the impact of the interference on the execution time by running programs taken from the TACLeBench benchmark suite, a popular benchmark suite in the real-time research community, on the first generation of Kalray manycore processor family, the MPPA-256 (the development board) that goes by the codename "Andey".
Cite as

Vincent Nélis, Patrick Meumeu Yomsi, and Luís Miguel Pinho. The Variability of Application Execution Times on a Multi-Core Platform. In 16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016). Open Access Series in Informatics (OASIcs), Volume 55, pp. 6:1-6:11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@InProceedings{nelis_et_al:OASIcs.WCET.2016.6,
  author =	{N\'{e}lis, Vincent and Yomsi, Patrick Meumeu and Pinho, Lu{\'\i}s Miguel},
  title =	{{The Variability of Application Execution Times on a Multi-Core Platform}},
  booktitle =	{16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016)},
  pages =	{6:1--6:11},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-025-5},
  ISSN =	{2190-6807},
  year =	{2016},
  volume =	{55},
  editor =	{Schoeberl, Martin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2016.6},
  URN =		{urn:nbn:de:0030-drops-68994},
  doi =		{10.4230/OASIcs.WCET.2016.6},
  annote =	{Keywords: Execution time variability, timing analysis, WCET estimates, multi-cores, many-cores}
}
Document
DOI: 10.4230/OASIcs.GCB.2012.108
Computation and Visualization of Protein Topology Graphs Including Ligand Information

Authors: Tim Schäfer, Patrick May, and Ina Koch

Published in: OASIcs, Volume 26, German Conference on Bioinformatics 2012

Abstract
Motivation: Ligand information is of great interest to understand protein function. Protein structure topology can be modeled as a graph with secondary structure elements as vertices and spatial contacts between them as edges. Meaningful representations of such graphs in 2D are required for the visual inspection, comparison and analysis of protein folds, but their automatic visualization is still challenging. We present an approach which solves this task, supports different graph types and can optionally include ligand contacts. Results: Our method extends the field of protein structure description and visualization by including ligand information. It generates a mathematically unique representation and high- quality 2D plots of the secondary structure of a protein based on a protein-ligand graph. This graph is computed from 3D atom coordinates in PDB files and the corresponding SSE assignments of the DSSP algorithm. The related software supports different notations and allows a rapid visualization of protein structures. It can also export graphs in various standard file formats so they can be used with other software. Our approach visualizes ligands in relationship to protein structure topology and thus represents a useful tool for exploring protein structures. Availability: The software is released under an open source license and available at http://www.bioinformatik.uni-frankfurt.de/ in the Software section under Visualization of Protein Ligand Graphs.
Cite as

Tim Schäfer, Patrick May, and Ina Koch. Computation and Visualization of Protein Topology Graphs Including Ligand Information. In German Conference on Bioinformatics 2012. Open Access Series in Informatics (OASIcs), Volume 26, pp. 108-118, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{schafer_et_al:OASIcs.GCB.2012.108,
  author =	{Sch\"{a}fer, Tim and May, Patrick and Koch, Ina},
  title =	{{Computation and Visualization of Protein Topology Graphs Including Ligand Information}},
  booktitle =	{German Conference on Bioinformatics 2012},
  pages =	{108--118},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-44-6},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{26},
  editor =	{B\"{o}cker, Sebastian and Hufsky, Franziska and Scheubert, Kerstin and Schleicher, Jana and Schuster, Stefan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.GCB.2012.108},
  URN =		{urn:nbn:de:0030-drops-37226},
  doi =		{10.4230/OASIcs.GCB.2012.108},
  annote =	{Keywords: protein structure, graph theory, ligand, secondary structure, protein ligang graph}
}
Document
DOI: 10.4230/LIPIcs.CSL.2012.31
Interactive Realizability for Classical Peano Arithmetic with Skolem Axioms

Authors: Federico Aschieri

Published in: LIPIcs, Volume 16, Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL (2012)

Abstract
Interactive realizability is a computational semantics of classical Arithmetic. It is based on interactive learning and was originally designed to interpret excluded middle and Skolem axioms for simple existential formulas. A realizer represents a proof/construction depending on some state, which is an approximation of some Skolem functions. The realizer interacts with the environment, which may provide a counter-proof, a counterexample invalidating the current construction of the realizer. But the realizer is always able to turn such a negative outcome into a positive information, which consists in some new piece of knowledge learned about the mentioned Skolem functions. The aim of this work is to extend Interactive realizability to a system which includes classical first-order Peano Arithmetic with Skolem axioms. For witness extraction, the learning capabilities of realizers will be exploited according to the paradigm of learning by levels. In particular, realizers of atomic formulas will be update procedures in the sense of Avigad and thus will be understood as stratified-learning algorithms.
Cite as

Federico Aschieri. Interactive Realizability for Classical Peano Arithmetic with Skolem Axioms. In Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL. Leibniz International Proceedings in Informatics (LIPIcs), Volume 16, pp. 31-45, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{aschieri:LIPIcs.CSL.2012.31,
  author =	{Aschieri, Federico},
  title =	{{Interactive Realizability for Classical Peano Arithmetic with Skolem Axioms}},
  booktitle =	{Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL},
  pages =	{31--45},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-42-2},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{16},
  editor =	{C\'{e}gielski, Patrick and Durand, Arnaud},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2012.31},
  URN =		{urn:nbn:de:0030-drops-36629},
  doi =		{10.4230/LIPIcs.CSL.2012.31},
  annote =	{Keywords: Interactive realizability, learning, classical Arithmetic, witness extraction}
}
Document
DOI: 10.4230/LIPIcs.CSL.2012.183
A Systematic Approach to Canonicity in the Classical Sequent Calculus

Authors: Kaustuv Chaudhuri, Stefan Hetzl, and Dale Miller

Published in: LIPIcs, Volume 16, Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL (2012)

Abstract
The sequent calculus is often criticized for requiring proofs to contain large amounts of low-level syntactic details that can obscure the essence of a given proof. Because each inference rule introduces only a single connective, sequent proofs can separate closely related steps-such as instantiating a block of quantifiers-by irrelevant noise. Moreover, the sequential nature of sequent proofs forces proof steps that are syntactically non-interfering and permutable to nevertheless be written in some arbitrary order. The sequent calculus thus lacks a notion of canonicity: proofs that should be considered essentially the same may not have a common syntactic form. To fix this problem, many researchers have proposed replacing the sequent calculus with proof structures that are more parallel or geometric. Proof-nets, matings, and atomic flows are examples of such revolutionary formalisms. We propose, instead, an evolutionary approach to recover canonicity within the sequent calculus, which we illustrate for classical first-order logic. The essential element of our approach is the use of a multi-focused sequent calculus as the means of abstracting away the details from classical cut-free sequent proofs. We show that, among the multi-focused proofs, the maximally multi-focused proofs that make the foci as parallel as possible are canonical. Moreover, such proofs are isomorphic to expansion proofs - a well known, minimalistic, and parallel generalization of Herbrand disjunctions - for classical first-order logic. This technique is a systematic way to recover the desired essence of any sequent proof without abandoning the sequent calculus.
Cite as

Kaustuv Chaudhuri, Stefan Hetzl, and Dale Miller. A Systematic Approach to Canonicity in the Classical Sequent Calculus. In Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL. Leibniz International Proceedings in Informatics (LIPIcs), Volume 16, pp. 183-197, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{chaudhuri_et_al:LIPIcs.CSL.2012.183,
  author =	{Chaudhuri, Kaustuv and Hetzl, Stefan and Miller, Dale},
  title =	{{A Systematic Approach to Canonicity in the Classical Sequent Calculus}},
  booktitle =	{Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL},
  pages =	{183--197},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-42-2},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{16},
  editor =	{C\'{e}gielski, Patrick and Durand, Arnaud},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2012.183},
  URN =		{urn:nbn:de:0030-drops-36723},
  doi =		{10.4230/LIPIcs.CSL.2012.183},
  annote =	{Keywords: Sequent Calculus, Canonicity, Classical Logic, Expansion Trees}
}
Document
DOI: 10.4230/LIPIcs.CSL.2012.243
Bounded Combinatory Logic

Authors: Boris Düdder, Moritz Martens, Jakob Rehof, and Pawel Urzyczyn

Published in: LIPIcs, Volume 16, Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL (2012)

Abstract
In combinatory logic one usually assumes a fixed set of basic combinators (axiom schemes), usually K and S. In this setting the set of provable formulas (inhabited types) is PSPACE-complete in simple types and undecidable in intersection types. When arbitrary sets of axiom schemes are considered, the inhabitation problem is undecidable even in simple types (this is known as Linial-Post theorem). k-bounded combinatory logic with intersection types arises from combinatory logic by imposing the bound k on the depth of types (formulae) which may be substituted for type variables in axiom schemes. We consider the inhabitation (provability) problem for k-bounded combinatory logic: Given an arbitrary set of typed combinators and a type tau, is there a combinatory term of type tau in k-bounded combinatory logic? Our main result is that the problem is (k+2)-EXPTIME complete for k-bounded combinatory logic with intersection types, for every fixed k (and hence non-elementary when k is a parameter). We also show that the problem is EXPTIME-complete for simple types, for all k. Theoretically, our results give new insight into the expressive power of intersection types. From an application perspective, our results are useful as a foundation for composition synthesis based on combinatory logic.
Cite as

Boris Düdder, Moritz Martens, Jakob Rehof, and Pawel Urzyczyn. Bounded Combinatory Logic. In Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL. Leibniz International Proceedings in Informatics (LIPIcs), Volume 16, pp. 243-258, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{dudder_et_al:LIPIcs.CSL.2012.243,
  author =	{D\"{u}dder, Boris and Martens, Moritz and Rehof, Jakob and Urzyczyn, Pawel},
  title =	{{Bounded Combinatory Logic}},
  booktitle =	{Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL},
  pages =	{243--258},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-42-2},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{16},
  editor =	{C\'{e}gielski, Patrick and Durand, Arnaud},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2012.243},
  URN =		{urn:nbn:de:0030-drops-36763},
  doi =		{10.4230/LIPIcs.CSL.2012.243},
  annote =	{Keywords: Intersection types, Inhabitation, Composition synthesis}
}
Document
DOI: 10.4230/DagSemProc.05142.3
An Architecture for Tetherless Communication

Authors: Aaditeshwar Seth, Patrick Darragh, Suihong Liang, Yunfeng Lin, and Srinivasan Keshav

Published in: Dagstuhl Seminar Proceedings, Volume 5142, Disruption Tolerant Networking (2005)

Abstract
In the emerging paradigm of tetherless computing, client applications running on small, inexpensive, and smart mobile devices maintain opportunistic wireless connectivity with back-end services running on centralized computers, enabling novel classes of applications. These applications require a communications infrastrastructure that is mobility-aware, disconnection-resilient and provides support for an opportunistic style of communiction. It should even be able to function across network partitions that may arise when end-to-end communication is not possible. We outline, design, and evaluate the implementation of an architecture that provides this functionality. we shot that it is possible for next-generation mobile devices to obtain up to 80-fold improvement over conventional mechanisms by exploiting opportunistic WiFi links, and that this benefit can be delivered as an overlay that is compatible with the current Internet.
Cite as

Aaditeshwar Seth, Patrick Darragh, Suihong Liang, Yunfeng Lin, and Srinivasan Keshav. An Architecture for Tetherless Communication. In Disruption Tolerant Networking. Dagstuhl Seminar Proceedings, Volume 5142, pp. 1-13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2005)

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@InProceedings{seth_et_al:DagSemProc.05142.3,
  author =	{Seth, Aaditeshwar and Darragh, Patrick and Liang, Suihong and Lin, Yunfeng and Keshav, Srinivasan},
  title =	{{An Architecture for Tetherless Communication}},
  booktitle =	{Disruption Tolerant Networking},
  pages =	{1--13},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2005},
  volume =	{5142},
  editor =	{Marcus Brunner and Lars Eggert and Kevin Fall and J\"{o}rg Ott and Lars Wolf},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.05142.3},
  URN =		{urn:nbn:de:0030-drops-3519},
  doi =		{10.4230/DagSemProc.05142.3},
  annote =	{Keywords: Delay tolerant networks, Opportunistic communication, Tetherless computing, Wireless, Mobile}
}
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