3 Search Results for "Kiel, Stefan"


Document
The Edit Distance to k-Subsequence Universality

Authors: Joel D. Day, Pamela Fleischmann, Maria Kosche, Tore Koß, Florin Manea, and Stefan Siemer

Published in: LIPIcs, Volume 187, 38th International Symposium on Theoretical Aspects of Computer Science (STACS 2021)


Abstract
A word u is a subsequence of another word w if u can be obtained from w by deleting some of its letters. In the early 1970s, Imre Simon defined the relation ∼_k (called now Simon-Congruence) as follows: two words having exactly the same set of subsequences of length at most k are ∼_k-congruent. This relation was central in defining and analysing piecewise testable languages, but has found many applications in areas such as algorithmic learning theory, databases theory, or computational linguistics. Recently, it was shown that testing whether two words are ∼_k-congruent can be done in optimal linear time. Thus, it is a natural next step to ask, for two words w and u which are not ∼_k-equivalent, what is the minimal number of edit operations that we need to perform on w in order to obtain a word which is ∼_k-equivalent to u. In this paper, we consider this problem in a setting which seems interesting: when u is a k-subsequence universal word. A word u with alph(u) = Σ is called k-subsequence universal if the set of subsequences of length k of u contains all possible words of length k over Σ. As such, our results are a series of efficient algorithms computing the edit distance from w to the language of k-subsequence universal words.

Cite as

Joel D. Day, Pamela Fleischmann, Maria Kosche, Tore Koß, Florin Manea, and Stefan Siemer. The Edit Distance to k-Subsequence Universality. In 38th International Symposium on Theoretical Aspects of Computer Science (STACS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 187, pp. 25:1-25:19, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)


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@InProceedings{day_et_al:LIPIcs.STACS.2021.25,
  author =	{Day, Joel D. and Fleischmann, Pamela and Kosche, Maria and Ko{\ss}, Tore and Manea, Florin and Siemer, Stefan},
  title =	{{The Edit Distance to k-Subsequence Universality}},
  booktitle =	{38th International Symposium on Theoretical Aspects of Computer Science (STACS 2021)},
  pages =	{25:1--25:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-180-1},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{187},
  editor =	{Bl\"{a}ser, Markus and Monmege, Benjamin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2021.25},
  URN =		{urn:nbn:de:0030-drops-136705},
  doi =		{10.4230/LIPIcs.STACS.2021.25},
  annote =	{Keywords: Subsequence, Scattered factor, Subword, Universality, k-subsequence universality, Edit distance, Efficient algorithms}
}
Document
Complexity and Approximability of Parameterized MAX-CSPs

Authors: Holger Dell, Eun Jung Kim, Michael Lampis, Valia Mitsou, and Tobias Mömke

Published in: LIPIcs, Volume 43, 10th International Symposium on Parameterized and Exact Computation (IPEC 2015)


Abstract
We study the optimization version of constraint satisfaction problems (Max-CSPs) in the framework of parameterized complexity; the goal is to compute the maximum fraction of constraints that can be satisfied simultaneously. In standard CSPs, we want to decide whether this fraction equals one. The parameters we investigate are structural measures, such as the treewidth or the clique-width of the variable–constraint incidence graph of the CSP instance. We consider Max-CSPs with the constraint types AND, OR, PARITY, and MAJORITY, and with various parameters k. We attempt to fully classify them into the following three cases: 1. The exact optimum can be computed in FPT-time. 2. It is W[1]-hard to compute the exact optimum, but there is a randomized FPT approximation scheme (FPT-AS), which computes a (1-epsilon)-approximation in time f(k,epsilon) * poly(n). 3. There is no FPT-AS unless FPT=W[1]. For the corresponding standard CSPs, we establish FPT vs. W[1]-hardness results.

Cite as

Holger Dell, Eun Jung Kim, Michael Lampis, Valia Mitsou, and Tobias Mömke. Complexity and Approximability of Parameterized MAX-CSPs. In 10th International Symposium on Parameterized and Exact Computation (IPEC 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 43, pp. 294-306, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)


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@InProceedings{dell_et_al:LIPIcs.IPEC.2015.294,
  author =	{Dell, Holger and Kim, Eun Jung and Lampis, Michael and Mitsou, Valia and M\"{o}mke, Tobias},
  title =	{{Complexity and Approximability of Parameterized MAX-CSPs}},
  booktitle =	{10th International Symposium on Parameterized and Exact Computation (IPEC 2015)},
  pages =	{294--306},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-92-7},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{43},
  editor =	{Husfeldt, Thore and Kanj, Iyad},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.IPEC.2015.294},
  URN =		{urn:nbn:de:0030-drops-55910},
  doi =		{10.4230/LIPIcs.IPEC.2015.294},
  annote =	{Keywords: Approximation, Structural Parameters, Constraint Satisfaction}
}
Document
Verification and Validation for Femur Prosthesis Surgery

Authors: Ekaterina Auer, Roger Cuypers, Eva Dyllong, Stefan Kiel, and Wolfram Luther

Published in: Dagstuhl Seminar Proceedings, Volume 9471, Computer-assisted proofs - tools, methods and applications (2010)


Abstract
In this paper, we describe how verified methods we are developing in the course of the project TellHim&S (Interval Based Methods For Adaptive Hierarchical Models In Modeling And Simulation Systems) can be applied in the context of the biomechanical project PROREOP (Development of a new prognosis system to optimize patient-specific pre- operative surgical planning for the human skeletal system). On the one hand, it includes the use of verified hierarchical structures for reliable geometric modeling, object decomposition, distance computation and path planning. On the other hand, we cover such tasks as verification and validation assessment and propagation of differently described uncertainties through system models in engineering or mechanics.

Cite as

Ekaterina Auer, Roger Cuypers, Eva Dyllong, Stefan Kiel, and Wolfram Luther. Verification and Validation for Femur Prosthesis Surgery. In Computer-assisted proofs - tools, methods and applications. Dagstuhl Seminar Proceedings, Volume 9471, pp. 1-22, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2010)


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@InProceedings{auer_et_al:DagSemProc.09471.4,
  author =	{Auer, Ekaterina and Cuypers, Roger and Dyllong, Eva and Kiel, Stefan and Luther, Wolfram},
  title =	{{Verification and Validation for Femur Prosthesis Surgery}},
  booktitle =	{Computer-assisted proofs - tools, methods and applications},
  pages =	{1--22},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2010},
  volume =	{9471},
  editor =	{B. Malcolm Brown and Erich Kaltofen and Shin'ichi Oishi and Siegfried M. Rump},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.09471.4},
  URN =		{urn:nbn:de:0030-drops-25133},
  doi =		{10.4230/DagSemProc.09471.4},
  annote =	{Keywords: Graphical interface construction, superquadrics, 3D modeling, biomedical engineering}
}
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