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Documents authored by Larsen, Kim Guldstrand

Found 4 Possible Name Variants:

Larsen, Kim G.

Document
Invited Paper
DOI: 10.4230/LIPIcs.CONCUR.2019.2
Synthesis of Safe, Optimal and Compact Strategies for Stochastic Hybrid Games (Invited Paper)

Authors: Kim G. Larsen

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

Abstract
UPPAAL-Stratego is a recent branch of the verification tool UPPAAL allowing for synthesis of safe and optimal strategies for stochastic timed (hybrid) games. We describe newly developed learning methods, allowing for synthesis of significantly better strategies and with much improved convergence behaviour. Also, we describe novel use of decision trees for learning orders-of-magnitude more compact strategy representation. In both cases, the seek for optimality does not compromise safety.
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Kim G. Larsen. Synthesis of Safe, Optimal and Compact Strategies for Stochastic Hybrid Games (Invited Paper). In 30th International Conference on Concurrency Theory (CONCUR 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 140, pp. 2:1-2:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{larsen:LIPIcs.CONCUR.2019.2,
  author =	{Larsen, Kim G.},
  title =	{{Synthesis of Safe, Optimal and Compact Strategies for Stochastic Hybrid Games}},
  booktitle =	{30th International Conference on Concurrency Theory (CONCUR 2019)},
  pages =	{2:1--2:5},
  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.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2019.2},
  URN =		{urn:nbn:de:0030-drops-109048},
  doi =		{10.4230/LIPIcs.CONCUR.2019.2},
  annote =	{Keywords: Timed automata, Stochastic hybrid grame, Symbolic synthesis, Reinforcement learning, Q-learning, M-learning}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2019.9
Computing Probabilistic Bisimilarity Distances for Probabilistic Automata

Authors: Giorgio Bacci, Giovanni Bacci, Kim G. Larsen, Radu Mardare, Qiyi Tang, and Franck van Breugel

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

Abstract
The probabilistic bisimilarity distance of Deng et al. has been proposed as a robust quantitative generalization of Segala and Lynch’s probabilistic bisimilarity for probabilistic automata. In this paper, we present a novel characterization of the bisimilarity distance as the solution of a simple stochastic game. The characterization gives us an algorithm to compute the distances by applying Condon’s simple policy iteration on these games. The correctness of Condon’s approach, however, relies on the assumption that the games are stopping. Our games may be non-stopping in general, yet we are able to prove termination for this extended class of games. Already other algorithms have been proposed in the literature to compute these distances, with complexity in UP cap coUP and PPAD. Despite the theoretical relevance, these algorithms are inefficient in practice. To the best of our knowledge, our algorithm is the first practical solution. In the proofs of all the above-mentioned results, an alternative presentation of the Hausdorff distance due to Mémoli plays a central rôle.
Cite as

Giorgio Bacci, Giovanni Bacci, Kim G. Larsen, Radu Mardare, Qiyi Tang, and Franck van Breugel. Computing Probabilistic Bisimilarity Distances for Probabilistic Automata. In 30th International Conference on Concurrency Theory (CONCUR 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 140, pp. 9:1-9:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{bacci_et_al:LIPIcs.CONCUR.2019.9,
  author =	{Bacci, Giorgio and Bacci, Giovanni and Larsen, Kim G. and Mardare, Radu and Tang, Qiyi and van Breugel, Franck},
  title =	{{Computing Probabilistic Bisimilarity Distances for Probabilistic Automata}},
  booktitle =	{30th International Conference on Concurrency Theory (CONCUR 2019)},
  pages =	{9:1--9:17},
  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.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2019.9},
  URN =		{urn:nbn:de:0030-drops-109119},
  doi =		{10.4230/LIPIcs.CONCUR.2019.9},
  annote =	{Keywords: Probabilistic automata, Behavioural metrics, Simple stochastic games, Simple policy iteration algorithm}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2019.23
Partial Order Reduction for Reachability Games

Authors: Frederik Meyer Bønneland, Peter Gjøl Jensen, Kim G. Larsen, Marco Muñiz, and Jiří Srba

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

Abstract
Partial order reductions have been successfully applied to model checking of concurrent systems and practical applications of the technique show nontrivial reduction in the size of the explored state space. We present a theory of partial order reduction based on stubborn sets in the game-theoretical setting of 2-player games with reachability/safety objectives. Our stubborn reduction allows us to prune the interleaving behaviour of both players in the game, and we formally prove its correctness on the class of games played on general labelled transition systems. We then instantiate the framework to the class of weighted Petri net games with inhibitor arcs and provide its efficient implementation in the model checker TAPAAL. Finally, we evaluate our stubborn reduction on several case studies and demonstrate its efficiency.
Cite as

Frederik Meyer Bønneland, Peter Gjøl Jensen, Kim G. Larsen, Marco Muñiz, and Jiří Srba. Partial Order Reduction for Reachability Games. In 30th International Conference on Concurrency Theory (CONCUR 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 140, pp. 23:1-23:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{bnneland_et_al:LIPIcs.CONCUR.2019.23,
  author =	{B{\o}nneland, Frederik Meyer and Jensen, Peter Gj{\o}l and Larsen, Kim G. and Mu\~{n}iz, Marco and Srba, Ji\v{r}{\'\i}},
  title =	{{Partial Order Reduction for Reachability Games}},
  booktitle =	{30th International Conference on Concurrency Theory (CONCUR 2019)},
  pages =	{23:1--23:15},
  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.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2019.23},
  URN =		{urn:nbn:de:0030-drops-109251},
  doi =		{10.4230/LIPIcs.CONCUR.2019.23},
  annote =	{Keywords: Petri nets, games, synthesis, partial order reduction, stubborn sets}
}
Document
Complete Volume
DOI: 10.4230/LIPIcs.MFCS.2017
LIPIcs, Volume 83, MFCS'17, Complete Volume

Authors: Kim G. Larsen, Hans L. Bodlaender, and Jean-Francois Raskin

Published in: LIPIcs, Volume 83, 42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017)

Abstract
LIPIcs, Volume 83, MFCS'17, Complete Volume
Cite as

42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 83, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@Proceedings{larsen_et_al:LIPIcs.MFCS.2017,
  title =	{{LIPIcs, Volume 83, MFCS'17, Complete Volume}},
  booktitle =	{42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017)},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-046-0},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{83},
  editor =	{Larsen, Kim G. and Bodlaender, Hans L. and Raskin, Jean-Francois},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2017},
  URN =		{urn:nbn:de:0030-drops-82073},
  doi =		{10.4230/LIPIcs.MFCS.2017},
  annote =	{Keywords: Theory of Computation}
}
Document
Front Matter
DOI: 10.4230/LIPIcs.MFCS.2017.0
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Kim G. Larsen, Hans L. Bodlaender, and Jean-Francois Raskin

Published in: LIPIcs, Volume 83, 42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017)

Abstract
Front Matter, Table of Contents, Preface, Conference Organization
Cite as

42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 83, pp. 0:i-0:xvi, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{larsen_et_al:LIPIcs.MFCS.2017.0,
  author =	{Larsen, Kim G. and Bodlaender, Hans L. and Raskin, Jean-Francois},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017)},
  pages =	{0:i--0:xvi},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-046-0},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{83},
  editor =	{Larsen, Kim G. and Bodlaender, Hans L. and Raskin, Jean-Francois},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2017.0},
  URN =		{urn:nbn:de:0030-drops-80564},
  doi =		{10.4230/LIPIcs.MFCS.2017.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
DOI: 10.4230/LIPIcs.ICALP.2017.104
On the Metric-Based Approximate Minimization of Markov Chains

Authors: Giovanni Bacci, Giorgio Bacci, Kim G. Larsen, and Radu Mardare

Published in: LIPIcs, Volume 80, 44th International Colloquium on Automata, Languages, and Programming (ICALP 2017)

Abstract
We address the behavioral metric-based approximate minimization problem of Markov Chains (MCs), i.e., given a finite MC and a positive integer k, we are interested in finding a k-state MC of minimal distance to the original. By considering as metric the bisimilarity distance of Desharnais at al., we show that optimal approximations always exist; show that the problem can be solved as a bilinear program; and prove that its threshold problem is in PSPACE and NP-hard. Finally, we present an approach inspired by expectation maximization techniques that provides suboptimal solutions. Experiments suggest that our method gives a practical approach that outperforms the bilinear program implementation run on state-of-the-art bilinear solvers.
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Giovanni Bacci, Giorgio Bacci, Kim G. Larsen, and Radu Mardare. On the Metric-Based Approximate Minimization of Markov Chains. In 44th International Colloquium on Automata, Languages, and Programming (ICALP 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 80, pp. 104:1-104:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{bacci_et_al:LIPIcs.ICALP.2017.104,
  author =	{Bacci, Giovanni and Bacci, Giorgio and Larsen, Kim G. and Mardare, Radu},
  title =	{{On the Metric-Based Approximate Minimization of Markov Chains}},
  booktitle =	{44th International Colloquium on Automata, Languages, and Programming (ICALP 2017)},
  pages =	{104:1--104:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-041-5},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{80},
  editor =	{Chatzigiannakis, Ioannis and Indyk, Piotr and Kuhn, Fabian and Muscholl, Anca},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2017.104},
  URN =		{urn:nbn:de:0030-drops-73675},
  doi =		{10.4230/LIPIcs.ICALP.2017.104},
  annote =	{Keywords: Behavioral distances, Probabilistic Models, Automata Minimization}
}
Document
DOI: 10.4230/LIPIcs.OPODIS.2016.18
WNetKAT: A Weighted SDN Programming and Verification Language

Authors: Kim G. Larsen, Stefan Schmid, and Bingtian Xue

Published in: LIPIcs, Volume 70, 20th International Conference on Principles of Distributed Systems (OPODIS 2016)

Abstract
Programmability and verifiability lie at the heart of the software-defined networking paradigm. While OpenFlow and its match-action concept provide primitive operations to manipulate hardware configurations, over the last years, several more expressive network programming languages have been developed. This paper presents WNetKAT, the first network programming language accounting for the fact that networks are inherently weighted, and communications subject to capacity constraints (e.g., in terms of bandwidth) and costs (e.g., latency or monetary costs). WNetKAT is based on a syntactic and semantic extension of the NetKAT algebra. We demonstrate several relevant applications for WNetKAT, including cost and capacity-aware reachability, as well as quality-of-service and fairness aspects. These applications do not only apply to classic, splittable and unsplittable (s,t)-flows, but also generalize to more complex (and stateful) network functions and service chains. For example, WNetKAT allows to model flows which need to traverse certain waypoint functions, which can change the traffic rate. This paper also shows the relationship between the equivalence problem of WNetKAT and the equivalence problem of the weighted finite automata, which implies undecidability of the former. However, this paper also shows the decidability of whether an expression equals to 0, which is sufficient in many practical scenarios, and we initiate the discussion of decidable subsets of the whole language.
Cite as

Kim G. Larsen, Stefan Schmid, and Bingtian Xue. WNetKAT: A Weighted SDN Programming and Verification Language. In 20th International Conference on Principles of Distributed Systems (OPODIS 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 70, pp. 18:1-18:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{larsen_et_al:LIPIcs.OPODIS.2016.18,
  author =	{Larsen, Kim G. and Schmid, Stefan and Xue, Bingtian},
  title =	{{WNetKAT: A Weighted SDN Programming and Verification Language}},
  booktitle =	{20th International Conference on Principles of Distributed Systems (OPODIS 2016)},
  pages =	{18:1--18:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-031-6},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{70},
  editor =	{Fatourou, Panagiota and Jim\'{e}nez, Ernesto and Pedone, Fernando},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2016.18},
  URN =		{urn:nbn:de:0030-drops-70870},
  doi =		{10.4230/LIPIcs.OPODIS.2016.18},
  annote =	{Keywords: Software-Defined Networking, Verification, Reachability, Stateful Processing, Service Chains, Weighted Automata, Decidability, NetKAT}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2016.25
Probabilistic Mu-Calculus: Decidability and Complete Axiomatization

Authors: Kim G. Larsen, Radu Mardare, and Bingtian Xue

Published in: LIPIcs, Volume 65, 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)

Abstract
We introduce a version of the probabilistic mu-calculus (PMC) built on top of a probabilistic modal logic that allows encoding n-ary inequational conditions on transition probabilities. PMC extends previously studied calculi and we prove that, despite its expressiveness, it enjoys a series of good meta-properties. Firstly, we prove the decidability of satisfiability checking by establishing the small model property. An algorithm for deciding the satisfiability problem is developed. As a second major result, we provide a complete axiomatization for the alternation-free fragment of PMC. The completeness proof is innovative in many aspects combining various techniques from topology and model theory.
Cite as

Kim G. Larsen, Radu Mardare, and Bingtian Xue. Probabilistic Mu-Calculus: Decidability and Complete Axiomatization. In 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 65, pp. 25:1-25:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@InProceedings{larsen_et_al:LIPIcs.FSTTCS.2016.25,
  author =	{Larsen, Kim G. and Mardare, Radu and Xue, Bingtian},
  title =	{{Probabilistic Mu-Calculus: Decidability and Complete Axiomatization}},
  booktitle =	{36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)},
  pages =	{25:1--25:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-027-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{65},
  editor =	{Lal, Akash and Akshay, S. and Saurabh, Saket and Sen, Sandeep},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2016.25},
  URN =		{urn:nbn:de:0030-drops-68607},
  doi =		{10.4230/LIPIcs.FSTTCS.2016.25},
  annote =	{Keywords: Markov process, probabilistic modal mu-calculus, n-ary (in-)equational modalities, satisfiability, axiomatization}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2014.121
Synchronizing Words for Weighted and Timed Automata

Authors: Laurent Doyen, Line Juhl, Kim G. Larsen, Nicolas Markey, and Mahsa Shirmohammadi

Published in: LIPIcs, Volume 29, 34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014)

Abstract
The problem of synchronizing automata is concerned with the existence of a word that sends all states of the automaton to one and the same state. This problem has classically been studied for complete deterministic finite automata, with the existence problem being NLOGSPACE-complete. In this paper we consider synchronizing-word problems for weighted and timed automata. We consider the synchronization problem in several variants and combinations of these, including deterministic and non-deterministic timed and weighted automata, synchronization to unique location with possibly different clock valuations or accumulated weights, as well as synchronization with a safety condition forbidding the automaton to visit states outside a safety-set during synchronization (e.g. energy constraints). For deterministic weighted automata, the synchronization problem is proven PSPACE-complete under energy constraints, and in 3-EXPSPACE under general safety constraints. For timed automata the synchronization problems are shown to be PSPACE-complete in the deterministic case, and undecidable in the non-deterministic case.
Cite as

Laurent Doyen, Line Juhl, Kim G. Larsen, Nicolas Markey, and Mahsa Shirmohammadi. Synchronizing Words for Weighted and Timed Automata. In 34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014). Leibniz International Proceedings in Informatics (LIPIcs), Volume 29, pp. 121-132, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@InProceedings{doyen_et_al:LIPIcs.FSTTCS.2014.121,
  author =	{Doyen, Laurent and Juhl, Line and Larsen, Kim G. and Markey, Nicolas and Shirmohammadi, Mahsa},
  title =	{{Synchronizing Words for Weighted and Timed Automata}},
  booktitle =	{34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014)},
  pages =	{121--132},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-77-4},
  ISSN =	{1868-8969},
  year =	{2014},
  volume =	{29},
  editor =	{Raman, Venkatesh and Suresh, S. P.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2014.121},
  URN =		{urn:nbn:de:0030-drops-48370},
  doi =		{10.4230/LIPIcs.FSTTCS.2014.121},
  annote =	{Keywords: Synchronizing words, weighted automata, timed automata}
}
Document
DOI: 10.4230/OASIcs.SSV.2011.32
Adaptable Value-Set Analysis for Low-Level Code

Authors: Jörg Brauer, René Rydhof Hansen, Stefan Kowalewski, Kim G. Larsen, and Mads Chr. Olesen

Published in: OASIcs, Volume 24, 6th International Workshop on Systems Software Verification (2012)

Abstract
This paper presents a framework for binary code analysis that uses only SAT-based algorithms. Within the framework, incremental SAT solving is used to perform a form of weakly relational value-set analysis in a novel way, connecting the expressiveness of the value sets to computational complexity. Another key feature of our framework is that it translates the semantics of binary code into an intermediate representation. This allows for a straightforward translation of the program semantics into Boolean logic and eases the implementation efforts, too. We show that leveraging the efficiency of contemporary SAT solvers allows us to prove interesting properties about medium-sized microcontroller programs.
Cite as

Jörg Brauer, René Rydhof Hansen, Stefan Kowalewski, Kim G. Larsen, and Mads Chr. Olesen. Adaptable Value-Set Analysis for Low-Level Code. In 6th International Workshop on Systems Software Verification. Open Access Series in Informatics (OASIcs), Volume 24, pp. 32-43, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{brauer_et_al:OASIcs.SSV.2011.32,
  author =	{Brauer, J\"{o}rg and Hansen, Ren\'{e} Rydhof and Kowalewski, Stefan and Larsen, Kim G. and Olesen, Mads Chr.},
  title =	{{Adaptable Value-Set Analysis for Low-Level Code}},
  booktitle =	{6th International Workshop on Systems Software Verification},
  pages =	{32--43},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-36-1},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{24},
  editor =	{Brauer, J\"{o}rg and Roveri, Marco and Tews, Hendrik},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SSV.2011.32},
  URN =		{urn:nbn:de:0030-drops-35884},
  doi =		{10.4230/OASIcs.SSV.2011.32},
  annote =	{Keywords: Abstract interpretation, SAT solving, embedded systems}
}
Document
DOI: 10.4230/LIPIcs.CSL.2011.144
Continuous Markovian Logic - From Complete Axiomatization to the Metric Space of Formulas

Authors: Luca Cardelli, Kim G. Larsen, and Radu Mardare

Published in: LIPIcs, Volume 12, Computer Science Logic (CSL'11) - 25th International Workshop/20th Annual Conference of the EACSL (2011)

Abstract
Continuous Markovian Logic (CML) is a multimodal logic that expresses quantitative and qualitative properties of continuous-space and continuous-time labelled Markov processes (CMPs). The modalities of CML approximate the rates of the exponentially distributed random variables that characterize the duration of the labeled transitions. In this paper we present a sound and complete Hilbert-style axiomatization of CML for the CMP-semantics and prove some metaproperties including the small model property. CML characterizes stochastic bisimulation and supports the definition of a quantified extension of satisfiability relation that measures the compatibility of a model and a property. Relying on the small model property, we prove that this measure can be approximated, within a given error, by using a distance between logical formulas.
Cite as

Luca Cardelli, Kim G. Larsen, and Radu Mardare. Continuous Markovian Logic - From Complete Axiomatization to the Metric Space of Formulas. In Computer Science Logic (CSL'11) - 25th International Workshop/20th Annual Conference of the EACSL. Leibniz International Proceedings in Informatics (LIPIcs), Volume 12, pp. 144-158, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

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@InProceedings{cardelli_et_al:LIPIcs.CSL.2011.144,
  author =	{Cardelli, Luca and Larsen, Kim G. and Mardare, Radu},
  title =	{{Continuous Markovian Logic - From Complete Axiomatization to the Metric Space of Formulas}},
  booktitle =	{Computer Science Logic (CSL'11) - 25th International Workshop/20th Annual Conference of the EACSL},
  pages =	{144--158},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-32-3},
  ISSN =	{1868-8969},
  year =	{2011},
  volume =	{12},
  editor =	{Bezem, Marc},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2011.144},
  URN =		{urn:nbn:de:0030-drops-32281},
  doi =		{10.4230/LIPIcs.CSL.2011.144},
  annote =	{Keywords: probabilistic logic, axiomatization, Markov processes, metric semantics}
}
Document
DOI: 10.4230/DROPS.MEMICS.2009.2345
A Quantitative Characterization of Weighted Kripke Structures in Temporal Logic

Authors: Kim G. Larsen, Uli Fahrenberg, and Claus Thrane

Published in: OASIcs, Volume 13, Annual Doctoral Workshop on Mathematical and Engineering Methods in Computer Science (MEMICS'09) (2009)

Abstract
We extend the usual notion of Kripke Structures with a weighted transition relation, and generalize the usual Boolean satisfaction relation of CTL to a map which assigns to states and temporal formulae a real-valued distance describing the degree of satisfaction. We describe a general approach to obtaining quantitative interpretations for a generic extension of the CTL syntax, and show that, for one such interpretation, the logic is both adequate and expressive with respect to quantitative bisimulation.
Cite as

Kim G. Larsen, Uli Fahrenberg, and Claus Thrane. A Quantitative Characterization of Weighted Kripke Structures in Temporal Logic. In Annual Doctoral Workshop on Mathematical and Engineering Methods in Computer Science (MEMICS'09). Open Access Series in Informatics (OASIcs), Volume 13, pp. 10-17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)

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@InProceedings{larsen_et_al:OASIcs:2009:DROPS.MEMICS.2009.2345,
  author =	{Larsen, Kim G. and Fahrenberg, Uli and Thrane, Claus},
  title =	{{A Quantitative Characterization of Weighted Kripke Structures in Temporal Logic}},
  booktitle =	{Annual Doctoral Workshop on Mathematical and Engineering Methods in Computer Science (MEMICS'09)},
  pages =	{10--17},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-15-6},
  ISSN =	{2190-6807},
  year =	{2009},
  volume =	{13},
  editor =	{Hlinen\'{y}, Petr and Maty\'{a}\v{s}, V\'{a}clav and Vojnar, Tom\'{a}\v{s}},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DROPS.MEMICS.2009.2345},
  URN =		{urn:nbn:de:0030-drops-23454},
  doi =		{10.4230/DROPS.MEMICS.2009.2345},
  annote =	{Keywords: Quantitative analysis, Kripke structures, characteristic formulae, bisimulation distance, weighted CTL}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2009.2337
Priced Timed Automata: Theory and Tools

Authors: Kim G. Larsen

Published in: LIPIcs, Volume 4, IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (2009)

Abstract
Priced timed automata are emerging as useful formalisms for modeling and analysing a broad range of resource allocation problems. In this extended abstract, we highlight recent (un)deci\-dability results related to priced timed automata as well as point to a number of open problems.
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Kim G. Larsen. Priced Timed Automata: Theory and Tools. In IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 4, pp. 417-425, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)

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@InProceedings{larsen:LIPIcs.FSTTCS.2009.2337,
  author =	{Larsen, Kim G.},
  title =	{{Priced Timed Automata: Theory and Tools}},
  booktitle =	{IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science},
  pages =	{417--425},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-13-2},
  ISSN =	{1868-8969},
  year =	{2009},
  volume =	{4},
  editor =	{Kannan, Ravi and Narayan Kumar, K.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2009.2337},
  URN =		{urn:nbn:de:0030-drops-23374},
  doi =		{10.4230/LIPIcs.FSTTCS.2009.2337},
  annote =	{Keywords: Timed systems, optimal scheduling, priced timed automata, games, model-checking}
}
Document
DOI: 10.4230/DagSemProc.04371.3
Online Testing of Real-Time Systems Using UPPAAL: Status and Future Work

Authors: Kim G. Larsen, Marius Mikucionis, and Brian Nielsen

Published in: Dagstuhl Seminar Proceedings, Volume 4371, Perspectives of Model-Based Testing (2005)

Abstract
We present TUPPAAL --- a new tool for online black-box testing of real-time embedded systems from non-deterministic timed automata specifications. We describe a sound and complete randomized online testing algorithm, and describe how to implement it using symbolic state representation and manipulation techniques. We propose the notion of relativized timed input/output conformance as the formal implementation relation. A novelty of this relation and our testing algorithm is that they explicitly take environment assumptions into account, generate, execute and verify the result online using the UPPAAL on-the-fly model-checking tool engine. A medium size case study shows promising results in terms of error detection capability and computation performance.
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Kim G. Larsen, Marius Mikucionis, and Brian Nielsen. Online Testing of Real-Time Systems Using UPPAAL: Status and Future Work. In Perspectives of Model-Based Testing. Dagstuhl Seminar Proceedings, Volume 4371, pp. 1-21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2005)

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@InProceedings{larsen_et_al:DagSemProc.04371.3,
  author =	{Larsen, Kim G. and Mikucionis, Marius and Nielsen, Brian},
  title =	{{Online Testing of Real-Time Systems Using UPPAAL: Status and Future Work}},
  booktitle =	{Perspectives of Model-Based Testing},
  pages =	{1--21},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2005},
  volume =	{4371},
  editor =	{Ed Brinksma and Wolfgang Grieskamp and Jan Tretmans},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.04371.3},
  URN =		{urn:nbn:de:0030-drops-3269},
  doi =		{10.4230/DagSemProc.04371.3},
  annote =	{Keywords: Online testing, black-box testing, real-time systems, embedded systems, symbolic state representation, relativized timed input/output conformance, mo}
}

Larsen, Kim Guldstrand

Document
DOI: 10.4230/OASIcs.SynCoP.2015.77
Parametric Verification of Weighted Systems

Authors: Peter Christoffersen, Mikkel Hansen, Anders Mariegaard, Julian Trier Ringsmose, Kim Guldstrand Larsen, and Radu Mardare

Published in: OASIcs, Volume 44, 2nd International Workshop on Synthesis of Complex Parameters (SynCoP'15) (2015)

Abstract
This paper addresses the problem of parametric model checking for weighted transition systems. We consider transition systems labelled with linear equations over a set of parameters and we use them to provide semantics for a parametric version of weighted CTL where the until and next operators are themselves indexed with linear equations. The parameters change the model-checking problem into a problem of computing a linear system of inequalities that characterizes the parameters that guarantee the satisfiability. To address this problem, we use parametric dependency graphs (PDGs) and we propose a global update function that yields an assignment to each node in a PDG. For an iterative application of the function, we prove that a fixed point assignment to PDG nodes exists and the set of assignments constitutes a well-quasi ordering, thus ensuring that the fixed point assignment can be found after finitely many iterations. To demonstrate the utility of our technique, we have implemented a prototype tool that computes the constraints on parameters for model checking problems.
Cite as

Peter Christoffersen, Mikkel Hansen, Anders Mariegaard, Julian Trier Ringsmose, Kim Guldstrand Larsen, and Radu Mardare. Parametric Verification of Weighted Systems. In 2nd International Workshop on Synthesis of Complex Parameters (SynCoP'15). Open Access Series in Informatics (OASIcs), Volume 44, pp. 77-90, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{christoffersen_et_al:OASIcs.SynCoP.2015.77,
  author =	{Christoffersen, Peter and Hansen, Mikkel and Mariegaard, Anders and Ringsmose, Julian Trier and Larsen, Kim Guldstrand and Mardare, Radu},
  title =	{{Parametric Verification of Weighted Systems}},
  booktitle =	{2nd International Workshop on Synthesis of Complex Parameters (SynCoP'15)},
  pages =	{77--90},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-82-8},
  ISSN =	{2190-6807},
  year =	{2015},
  volume =	{44},
  editor =	{Andr\'{e}, \'{E}tienne and Frehse, Goran},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SynCoP.2015.77},
  URN =		{urn:nbn:de:0030-drops-56115},
  doi =		{10.4230/OASIcs.SynCoP.2015.77},
  annote =	{Keywords: parametric weighted transition systems, parametric weighted CTL, parametric model checking, well-quasi ordering, tool}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2015.142
Polynomial Time Decidability of Weighted Synchronization under Partial Observability

Authors: Jan Kretinsky, Kim Guldstrand Larsen, Simon Laursen, and Jiri Srba

Published in: LIPIcs, Volume 42, 26th International Conference on Concurrency Theory (CONCUR 2015)

Abstract
We consider weighted automata with both positive and negative integer weights on edges and study the problem of synchronization using adaptive strategies that may only observe whether the current weight-level is negative or nonnegative. We show that the synchronization problem is decidable in polynomial time for deterministic weighted automata.
Cite as

Jan Kretinsky, Kim Guldstrand Larsen, Simon Laursen, and Jiri Srba. Polynomial Time Decidability of Weighted Synchronization under Partial Observability. In 26th International Conference on Concurrency Theory (CONCUR 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 42, pp. 142-154, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{kretinsky_et_al:LIPIcs.CONCUR.2015.142,
  author =	{Kretinsky, Jan and Larsen, Kim Guldstrand and Laursen, Simon and Srba, Jiri},
  title =	{{Polynomial Time Decidability of Weighted Synchronization under Partial Observability}},
  booktitle =	{26th International Conference on Concurrency Theory (CONCUR 2015)},
  pages =	{142--154},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-91-0},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{42},
  editor =	{Aceto, Luca and de Frutos Escrig, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2015.142},
  URN =		{urn:nbn:de:0030-drops-53927},
  doi =		{10.4230/LIPIcs.CONCUR.2015.142},
  annote =	{Keywords: weighted automata, partial observability, synchronization, complexity}
}
Document
DOI: 10.4230/OASIcs.WCET.2010.113
METAMOC: Modular Execution Time Analysis using Model Checking

Authors: Andreas E. Dalsgaard, Mads Chr. Olesen, Martin Toft, René Rydhof Hansen, and Kim Guldstrand Larsen

Published in: OASIcs, Volume 15, 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)

Abstract
Safe and tight worst-case execution times (WCETs) are important when scheduling hard real-time systems. This paper presents METAMOC, a modular method, based on model checking and static analysis, that determines safe and tight WCETs for programs running on platforms featuring caching and pipelining. The method works by constructing a UPPAAL model of the program being analysed and annotating the model with information from an inter-procedural value analysis. The program model is then combined with a model of the hardware platform and model checked for the WCET. Through support for the platforms ARM7, ARM9 and ATMEL AVR 8-bit, the modularity and retargetability of the method are demonstrated, as only the pipeline needs to be remodelled. Hardware modelling is performed in a state-of-the-art graphical modelling environment. Experiments on the Mälardalen WCET benchmark programs show that taking caching into account yields much tighter WCETs than without modelling caches, and that METAMOC is a sufficiently fast and versatile approach for WCET analysis.
Cite as

Andreas E. Dalsgaard, Mads Chr. Olesen, Martin Toft, René Rydhof Hansen, and Kim Guldstrand Larsen. METAMOC: Modular Execution Time Analysis using Model Checking. In 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010). Open Access Series in Informatics (OASIcs), Volume 15, pp. 113-123, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{dalsgaard_et_al:OASIcs.WCET.2010.113,
  author =	{Dalsgaard, Andreas E. and Olesen, Mads Chr. and Toft, Martin and Hansen, Ren\'{e} Rydhof and Larsen, Kim Guldstrand},
  title =	{{METAMOC: Modular Execution Time Analysis using Model Checking}},
  booktitle =	{10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)},
  pages =	{113--123},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-21-7},
  ISSN =	{2190-6807},
  year =	{2010},
  volume =	{15},
  editor =	{Lisper, Bj\"{o}rn},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2010.113},
  URN =		{urn:nbn:de:0030-drops-28319},
  doi =		{10.4230/OASIcs.WCET.2010.113},
  annote =	{Keywords: WCET analysis, timed automata, model checking, UPPAAL}
}
Document
DOI: 10.4230/DagSemProc.10031.1
10031 Abstracts Collection – Quantitative Models: Expressiveness and Analysis

Authors: Christel Baier, Manfred Droste, Paul Gastin, and Kim Guldstrand Larsen

Published in: Dagstuhl Seminar Proceedings, Volume 10031, Quantitative Models: Expressiveness and Analysis (2010)

Abstract
From Jan 18 to Jan 22, 2010, the Dagstuhl Seminar 10031 ``Quantitative Models: Expressiveness and Analysis '' was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available.
Cite as

Christel Baier, Manfred Droste, Paul Gastin, and Kim Guldstrand Larsen. 10031 Abstracts Collection – Quantitative Models: Expressiveness and Analysis. In Quantitative Models: Expressiveness and Analysis. Dagstuhl Seminar Proceedings, Volume 10031, pp. 1-15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{baier_et_al:DagSemProc.10031.1,
  author =	{Baier, Christel and Droste, Manfred and Gastin, Paul and Larsen, Kim Guldstrand},
  title =	{{10031 Abstracts Collection – Quantitative Models: Expressiveness and Analysis}},
  booktitle =	{Quantitative Models: Expressiveness and Analysis},
  pages =	{1--15},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2010},
  volume =	{10031},
  editor =	{Christel Baier and Manfred Droste and Paul Gastin and Kim Guldstrand Larsen},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.10031.1},
  URN =		{urn:nbn:de:0030-drops-26839},
  doi =		{10.4230/DagSemProc.10031.1},
  annote =	{Keywords: Quantitative models, quantitative analysis, timed and hybrid systems, probabilistic systems, weighted automata}
}
Document
DOI: 10.4230/DagSemProc.10031.2
10031 Executive Summary – Quantitative Models: Expressiveness and Analysis

Authors: Christel Baier, Manfred Droste, Paul Gastin, and Kim Guldstrand Larsen

Published in: Dagstuhl Seminar Proceedings, Volume 10031, Quantitative Models: Expressiveness and Analysis (2010)

Abstract
Quantitative models and quantitative analysis in Computer Science are currently intensively studied, resulting in a revision of the foundation of Computer Science where classical yes/no answers are replaced by quantitative analyses. The potential application areas are huge, e.g., performance analysis, operational research or embedded systems. The aim of the seminar was to address three fundamental topics which are closely related: quantitative analysis of real-time and hybrid systems; probabilistic analysis and stochastic automata; weighted automata. These three areas of research have mainly evolved independently so far and the relationship between them has emerged only recently. The seminar brought together leading researchers of the three areas, with the goal of future highly productive cross-fertilizations.
Cite as

Christel Baier, Manfred Droste, Paul Gastin, and Kim Guldstrand Larsen. 10031 Executive Summary – Quantitative Models: Expressiveness and Analysis. In Quantitative Models: Expressiveness and Analysis. Dagstuhl Seminar Proceedings, Volume 10031, pp. 1-2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{baier_et_al:DagSemProc.10031.2,
  author =	{Baier, Christel and Droste, Manfred and Gastin, Paul and Larsen, Kim Guldstrand},
  title =	{{10031 Executive Summary – Quantitative Models: Expressiveness and Analysis}},
  booktitle =	{Quantitative Models: Expressiveness and Analysis},
  pages =	{1--2},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2010},
  volume =	{10031},
  editor =	{Christel Baier and Manfred Droste and Paul Gastin and Kim Guldstrand Larsen},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.10031.2},
  URN =		{urn:nbn:de:0030-drops-26824},
  doi =		{10.4230/DagSemProc.10031.2},
  annote =	{Keywords: Quantitative models, quantitative analysis, timed and hybrid systems, probabilistic systems, weighted automata}
}

Larsen, Kim S.

Document
DOI: 10.4230/LIPIcs.SWAT.2024.16
On the Online Weighted Non-Crossing Matching Problem

Authors: Joan Boyar, Shahin Kamali, Kim S. Larsen, Ali Mohammad Lavasani, Yaqiao Li, and Denis Pankratov

Published in: LIPIcs, Volume 294, 19th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2024)

Abstract
We introduce and study the weighted version of an online matching problem in the Euclidean plane with non-crossing constraints: 2n points with non-negative weights arrive online, and an algorithm can match an arriving point to one of the unmatched previously arrived points. In the vanilla model, the decision on how to match (if at all) a newly arriving point is irrevocable. The goal is to maximize the total weight of matched points under the constraint that straight-line segments corresponding to the edges of the matching do not intersect. The unweighted version of the problem was introduced in the offline setting by Atallah in 1985, and this problem became a subject of study in the online setting with and without advice in several recent papers. We observe that deterministic online algorithms cannot guarantee a non-trivial competitive ratio for the weighted problem. We study various regimes of the problem which permit non-trivial online algorithms. In particular, when weights are restricted to the interval [1, U] we give a deterministic algorithm achieving competitive ratio Ω(2^{-2√{log U}}). We also prove that deterministic online algorithms cannot achieve competitive ratio better than O (2^{-√{log U}}). Interestingly, we establish that randomization alone suffices to achieve competitive ratio 1/3 even when there are no restrictions on the weights. Additionally, if one allows an online algorithm to revoke acceptances, then one can achieve a competitive ratio ≈ 0.2862 deterministically for arbitrary weights. We also establish a lower bound on the competitive ratio of randomized algorithms in the unweighted setting, and improve the best-known bound on advice complexity to achieve a perfect matching.
Cite as

Joan Boyar, Shahin Kamali, Kim S. Larsen, Ali Mohammad Lavasani, Yaqiao Li, and Denis Pankratov. On the Online Weighted Non-Crossing Matching Problem. In 19th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 294, pp. 16:1-16:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{boyar_et_al:LIPIcs.SWAT.2024.16,
  author =	{Boyar, Joan and Kamali, Shahin and Larsen, Kim S. and Lavasani, Ali Mohammad and Li, Yaqiao and Pankratov, Denis},
  title =	{{On the Online Weighted Non-Crossing Matching Problem}},
  booktitle =	{19th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2024)},
  pages =	{16:1--16:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-318-8},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{294},
  editor =	{Bodlaender, Hans L.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SWAT.2024.16},
  URN =		{urn:nbn:de:0030-drops-200567},
  doi =		{10.4230/LIPIcs.SWAT.2024.16},
  annote =	{Keywords: Online algorithms, weighted matching problem, Euclidean plane, non-crossing constraints, competitive analysis, randomized online algorithms, online algorithms with advice, online algorithms with revoking}
}
Document
DOI: 10.4230/LIPIcs.SWAT.2022.20
Online Unit Profit Knapsack with Untrusted Predictions

Authors: Joan Boyar, Lene M. Favrholdt, and Kim S. Larsen

Published in: LIPIcs, Volume 227, 18th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2022)

Abstract
A variant of the online knapsack problem is considered in the settings of trusted and untrusted predictions. In Unit Profit Knapsack, the items have unit profit, and it is easy to find an optimal solution offline: Pack as many of the smallest items as possible into the knapsack. For Online Unit Profit Knapsack, the competitive ratio is unbounded. In contrast, previous work on online algorithms with untrusted predictions generally studied problems where an online algorithm with a constant competitive ratio is known. The prediction, possibly obtained from a machine learning source, that our algorithm uses is the average size of those smallest items that fit in the knapsack. For the prediction error in this hard online problem, we use the ratio r = a/â where a is the actual value for this average size and â is the prediction. The algorithm presented achieves a competitive ratio of 1/(2r) for r ≥ 1 and r/2 for r ≤ 1. Using an adversary technique, we show that this is optimal in some sense, giving a trade-off in the competitive ratio attainable for different values of r. Note that the result for accurate advice, r = 1, is only 1/2, but we show that no deterministic algorithm knowing the value a can achieve a competitive ratio better than (e-1)/e ≈ 0.6321 and present an algorithm with a matching upper bound. We also show that this latter algorithm attains a competitive ratio of r (e-1)/e for r ≤ 1 and (e-r)/e for 1 ≤ r < e, and no deterministic algorithm can be better for both r < 1 and 1 < r < e.
Cite as

Joan Boyar, Lene M. Favrholdt, and Kim S. Larsen. Online Unit Profit Knapsack with Untrusted Predictions. In 18th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 227, pp. 20:1-20:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{boyar_et_al:LIPIcs.SWAT.2022.20,
  author =	{Boyar, Joan and Favrholdt, Lene M. and Larsen, Kim S.},
  title =	{{Online Unit Profit Knapsack with Untrusted Predictions}},
  booktitle =	{18th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2022)},
  pages =	{20:1--20:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-236-5},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{227},
  editor =	{Czumaj, Artur and Xin, Qin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SWAT.2022.20},
  URN =		{urn:nbn:de:0030-drops-161800},
  doi =		{10.4230/LIPIcs.SWAT.2022.20},
  annote =	{Keywords: online algorithms, untrusted predictions, knapsack problem, competitive analysis}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2017.14
Flight Planning in Free Route Airspaces

Authors: Casper Kehlet Jensen, Marco Chiarandini, and Kim S. Larsen

Published in: OASIcs, Volume 59, 17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017)

Abstract
We consider the problem of finding cheapest flight routes through free route airspaces in a 2D setting. We subdivide the airspace into regions determined by a Voronoi subdivision around the points from a weather forecast. This gives rise to a regular grid of rectangular regions (quads) with every quad having an associated vector-weight that represents the wind magnitude and direction. Finding a cheapest path in this setting corresponds to finding a piece-wise linear path determined by points on the boundaries of the quads. In our solution approach, we discretize such boundaries by introducing border points and only consider segments connecting border points belonging to the same quad. While classic shortest path graph algorithms are available and applicable to the graphs originating from these border points, we design an algorithm that exploits the geometric structure of our scenario and show that this algorithm is more efficient in practice than classic graph-based algorithms. In particular, it scales better with the number of quads in the subdivision of the airspace, making it possible to find more accurate routes or to solve larger problems.
Cite as

Casper Kehlet Jensen, Marco Chiarandini, and Kim S. Larsen. Flight Planning in Free Route Airspaces. In 17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017). Open Access Series in Informatics (OASIcs), Volume 59, pp. 14:1-14:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)

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@InProceedings{jensen_et_al:OASIcs.ATMOS.2017.14,
  author =	{Jensen, Casper Kehlet and Chiarandini, Marco and Larsen, Kim S.},
  title =	{{Flight Planning in Free Route Airspaces}},
  booktitle =	{17th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2017)},
  pages =	{14:1--14:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-042-2},
  ISSN =	{2190-6807},
  year =	{2017},
  volume =	{59},
  editor =	{D'Angelo, Gianlorenzo and Dollevoet, Twan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2017.14},
  URN =		{urn:nbn:de:0030-drops-79047},
  doi =		{10.4230/OASIcs.ATMOS.2017.14},
  annote =	{Keywords: Flight planning, Geometric shortest path, Free route airspace, Vector weighted paths, Vector weighted planar subdivisions}
}
Document
DOI: 10.4230/LIPIcs.SWAT.2016.21
Online Dominating Set

Authors: Joan Boyar, Stephan J. Eidenbenz, Lene M. Favrholdt, Michal Kotrbcik, and Kim S. Larsen

Published in: LIPIcs, Volume 53, 15th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2016)

Abstract
This paper is devoted to the online dominating set problem and its variants on trees, bipartite, bounded-degree, planar, and general graphs, distinguishing between connected and not necessarily connected graphs. We believe this paper represents the first systematic study of the effect of two limitations of online algorithms: making irrevocable decisions while not knowing the future, and being incremental, i.e., having to maintain solutions to all prefixes of the input. This is quantified through competitive analyses of online algorithms against two optimal algorithms, both knowing the entire input, but only one having to be incremental. We also consider the competitive ratio of the weaker of the two optimal algorithms against the other. In most cases, we obtain tight bounds on the competitive ratios. Our results show that requiring the graphs to be presented in a connected fashion allows the online algorithms to obtain provably better solutions. Furthermore, we get detailed information regarding the significance of the necessary requirement that online algorithms be incremental. In some cases, having to be incremental fully accounts for the online algorithm's disadvantage.
Cite as

Joan Boyar, Stephan J. Eidenbenz, Lene M. Favrholdt, Michal Kotrbcik, and Kim S. Larsen. Online Dominating Set. In 15th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 53, pp. 21:1-21:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@InProceedings{boyar_et_al:LIPIcs.SWAT.2016.21,
  author =	{Boyar, Joan and Eidenbenz, Stephan J. and Favrholdt, Lene M. and Kotrbcik, Michal and Larsen, Kim S.},
  title =	{{Online Dominating Set}},
  booktitle =	{15th Scandinavian Symposium and Workshops on Algorithm Theory (SWAT 2016)},
  pages =	{21:1--21:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-011-8},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{53},
  editor =	{Pagh, Rasmus},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SWAT.2016.21},
  URN =		{urn:nbn:de:0030-drops-60434},
  doi =		{10.4230/LIPIcs.SWAT.2016.21},
  annote =	{Keywords: online algorithms, dominating set, competitive analysis, graph classes, connected graphs}
}
Document
DOI: 10.4230/LIPIcs.STACS.2014.174
Online Bin Packing with Advice

Authors: Joan Boyar, Shahin Kamali, Kim S. Larsen, and Alejandro López-Ortiz

Published in: LIPIcs, Volume 25, 31st International Symposium on Theoretical Aspects of Computer Science (STACS 2014)

Abstract
We consider the online bin packing problem under the advice complexity model where the "online constraint" is relaxed and an algorithm receives partial information about the future requests. We provide tight upper and lower bounds for the amount of advice an algorithm needs to achieve an optimal packing. We also introduce an algorithm that, when provided with log(n)+o(log(n)) bits of advice, achieves a competitive ratio of 3/2 for the general problem. This algorithm is simple and is expected to find real-world applications. We introduce another algorithm that receives 2n+o(n) bits of advice and achieves a competitive ratio of 4/3+e. Finally, we provide a lower bound argument that implies that advice of linear size is required for an algorithm to achieve a competitive ratio better than 9/8.
Cite as

Joan Boyar, Shahin Kamali, Kim S. Larsen, and Alejandro López-Ortiz. Online Bin Packing with Advice. In 31st International Symposium on Theoretical Aspects of Computer Science (STACS 2014). Leibniz International Proceedings in Informatics (LIPIcs), Volume 25, pp. 174-186, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@InProceedings{boyar_et_al:LIPIcs.STACS.2014.174,
  author =	{Boyar, Joan and Kamali, Shahin and Larsen, Kim S. and L\'{o}pez-Ortiz, Alejandro},
  title =	{{Online Bin Packing with Advice}},
  booktitle =	{31st International Symposium on Theoretical Aspects of Computer Science (STACS 2014)},
  pages =	{174--186},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-65-1},
  ISSN =	{1868-8969},
  year =	{2014},
  volume =	{25},
  editor =	{Mayr, Ernst W. and Portier, Natacha},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2014.174},
  URN =		{urn:nbn:de:0030-drops-44565},
  doi =		{10.4230/LIPIcs.STACS.2014.174},
  annote =	{Keywords: online algorithms, advice complexity, bin packing}
}

Larsen, Kim Gulstrand

Document
DOI: 10.4230/DagRep.4.1.104
Quantitative Models: Expressiveness, Analysis, and New Applications (Dagstuhl Seminar 14041)

Authors: Manfred Droste, Paul Gastin, Kim Gulstrand Larsen, and Axel Legay

Published in: Dagstuhl Reports, Volume 4, Issue 1 (2014)

Abstract
From Jan. 19 to Jan. 24, 2014, "Quantitative Models: Expressiveness, Analysis, and New Applications" was held in Schloss Dagstuhl-Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available.
Cite as

Manfred Droste, Paul Gastin, Kim Gulstrand Larsen, and Axel Legay. Quantitative Models: Expressiveness, Analysis, and New Applications (Dagstuhl Seminar 14041). In Dagstuhl Reports, Volume 4, Issue 1, pp. 104-124, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@Article{droste_et_al:DagRep.4.1.104,
  author =	{Droste, Manfred and Gastin, Paul and Larsen, Kim Gulstrand and Legay, Axel},
  title =	{{Quantitative Models: Expressiveness, Analysis, and New Applications (Dagstuhl Seminar 14041)}},
  pages =	{104--124},
  journal =	{Dagstuhl Reports},
  ISSN =	{2192-5283},
  year =	{2014},
  volume =	{4},
  number =	{1},
  editor =	{Droste, Manfred and Gastin, Paul and Larsen, Kim Gulstrand and Legay, Axel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagRep.4.1.104},
  URN =		{urn:nbn:de:0030-drops-45374},
  doi =		{10.4230/DagRep.4.1.104},
  annote =	{Keywords: quantitative models, quantitative analysis, timed and hybrid systems, probabilistic systems, weighted automata, systems biology, smart grid}
}
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