7 Search Results for "Wagner, Stefan"


Document
Exploring Maintainability Assurance Research for Service- and Microservice-Based Systems: Directions and Differences

Authors: Justus Bogner, Adrian Weller, Stefan Wagner, and Alfred Zimmermann

Published in: OASIcs, Volume 78, Joint Post-proceedings of the First and Second International Conference on Microservices (Microservices 2017/2019)


Abstract
To ensure sustainable software maintenance and evolution, a diverse set of activities and concepts like metrics, change impact analysis, or antipattern detection can be used. Special maintainability assurance techniques have been proposed for service- and microservice-based systems, but it is difficult to get a comprehensive overview of this publication landscape. We therefore conducted a systematic literature review (SLR) to collect and categorize maintainability assurance approaches for service-oriented architecture (SOA) and microservices. Our search strategy led to the selection of 223 primary studies from 2007 to 2018 which we categorized with a threefold taxonomy: a) architectural (SOA, microservices, both), b) methodical (method or contribution of the study), and c) thematic (maintainability assurance subfield). We discuss the distribution among these categories and present different research directions as well as exemplary studies per thematic category. The primary finding of our SLR is that, while very few approaches have been suggested for microservices so far (24 of 223, ∼11%), we identified several thematic categories where existing SOA techniques could be adapted for the maintainability assurance of microservices.

Cite as

Justus Bogner, Adrian Weller, Stefan Wagner, and Alfred Zimmermann. Exploring Maintainability Assurance Research for Service- and Microservice-Based Systems: Directions and Differences. In Joint Post-proceedings of the First and Second International Conference on Microservices (Microservices 2017/2019). Open Access Series in Informatics (OASIcs), Volume 78, pp. 3:1-3:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{bogner_et_al:OASIcs.Microservices.2017-2019.3,
  author =	{Bogner, Justus and Weller, Adrian and Wagner, Stefan and Zimmermann, Alfred},
  title =	{{Exploring Maintainability Assurance Research for Service- and Microservice-Based Systems: Directions and Differences}},
  booktitle =	{Joint Post-proceedings of the First and Second International Conference on Microservices (Microservices 2017/2019)},
  pages =	{3:1--3:22},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-137-5},
  ISSN =	{2190-6807},
  year =	{2020},
  volume =	{78},
  editor =	{Cruz-Filipe, Lu{\'\i}s and Giallorenzo, Saverio and Montesi, Fabrizio and Peressotti, Marco and Rademacher, Florian and Sachweh, Sabine},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.Microservices.2017-2019.3},
  URN =		{urn:nbn:de:0030-drops-118255},
  doi =		{10.4230/OASIcs.Microservices.2017-2019.3},
  annote =	{Keywords: Maintainability, Software Evolution, Quality Assurance, Service-Based Systems, SOA, Microservices, Systematic Literature Review}
}
Document
The Crossing Tverberg Theorem

Authors: Radoslav Fulek, Bernd Gärtner, Andrey Kupavskii, Pavel Valtr, and Uli Wagner

Published in: LIPIcs, Volume 129, 35th International Symposium on Computational Geometry (SoCG 2019)


Abstract
The Tverberg theorem is one of the cornerstones of discrete geometry. It states that, given a set X of at least (d+1)(r-1)+1 points in R^d, one can find a partition X=X_1 cup ... cup X_r of X, such that the convex hulls of the X_i, i=1,...,r, all share a common point. In this paper, we prove a strengthening of this theorem that guarantees a partition which, in addition to the above, has the property that the boundaries of full-dimensional convex hulls have pairwise nonempty intersections. Possible generalizations and algorithmic aspects are also discussed. As a concrete application, we show that any n points in the plane in general position span floor[n/3] vertex-disjoint triangles that are pairwise crossing, meaning that their boundaries have pairwise nonempty intersections; this number is clearly best possible. A previous result of Alvarez-Rebollar et al. guarantees floor[n/6] pairwise crossing triangles. Our result generalizes to a result about simplices in R^d,d >=2.

Cite as

Radoslav Fulek, Bernd Gärtner, Andrey Kupavskii, Pavel Valtr, and Uli Wagner. The Crossing Tverberg Theorem. In 35th International Symposium on Computational Geometry (SoCG 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 129, pp. 38:1-38:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{fulek_et_al:LIPIcs.SoCG.2019.38,
  author =	{Fulek, Radoslav and G\"{a}rtner, Bernd and Kupavskii, Andrey and Valtr, Pavel and Wagner, Uli},
  title =	{{The Crossing Tverberg Theorem}},
  booktitle =	{35th International Symposium on Computational Geometry (SoCG 2019)},
  pages =	{38:1--38:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-104-7},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{129},
  editor =	{Barequet, Gill and Wang, Yusu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2019.38},
  URN =		{urn:nbn:de:0030-drops-104423},
  doi =		{10.4230/LIPIcs.SoCG.2019.38},
  annote =	{Keywords: Discrete geometry, Tverberg theorem, Crossing Tverberg theorem}
}
Document
Topological Self-Stabilization with Name-Passing Process Calculi

Authors: Christina Rickmann, Christoph Wagner, Uwe Nestmann, and Stefan Schmid

Published in: LIPIcs, Volume 59, 27th International Conference on Concurrency Theory (CONCUR 2016)


Abstract
Topological self-stabilization is the ability of a distributed system to have its nodes themselves establish a meaningful overlay network. Independent from the initial network topology, it converges to the desired topology via forwarding, inserting, and deleting links to neighboring nodes. We adapt a linearization algorithm, originally designed for a shared memory model, to asynchronous message-passing. We use an extended localized pi-calculus to model the algorithm and to formally prove its essential self-stabilization properties: closure and weak convergence for every arbitrary initial configuration, and strong convergence for restricted cases.

Cite as

Christina Rickmann, Christoph Wagner, Uwe Nestmann, and Stefan Schmid. Topological Self-Stabilization with Name-Passing Process Calculi. In 27th International Conference on Concurrency Theory (CONCUR 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 59, pp. 19:1-19:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{rickmann_et_al:LIPIcs.CONCUR.2016.19,
  author =	{Rickmann, Christina and Wagner, Christoph and Nestmann, Uwe and Schmid, Stefan},
  title =	{{Topological Self-Stabilization with Name-Passing Process Calculi}},
  booktitle =	{27th International Conference on Concurrency Theory (CONCUR 2016)},
  pages =	{19:1--19:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-017-0},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{59},
  editor =	{Desharnais, Jos\'{e}e and Jagadeesan, Radha},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2016.19},
  URN =		{urn:nbn:de:0030-drops-61761},
  doi =		{10.4230/LIPIcs.CONCUR.2016.19},
  annote =	{Keywords: Distributed Algorithms, Fault Tolerance, Topological Self-Stabilization, Linearization, Process Calculi}
}
Document
Delay-Robust Journeys in Timetable Networks with Minimum Expected Arrival Time

Authors: Julian Dibbelt, Ben Strasser, and Dorothea Wagner

Published in: OASIcs, Volume 42, 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2014)


Abstract
We study the problem of computing delay-robust routes in timetable networks. Instead of a single path we compute a decision graph containing all stops and trains/vehicles that might be relevant. Delays are formalized using a stochastic model. We show how to compute a decision graph that minimizes the expected arrival time while bounding the latest arrival time over all sub-paths. Finally we show how the information contained within a decision graph can compactly be represented to the user. We experimentally evaluate our algorithms and show that the running times allow for interactive usage on a realistic train network.

Cite as

Julian Dibbelt, Ben Strasser, and Dorothea Wagner. Delay-Robust Journeys in Timetable Networks with Minimum Expected Arrival Time. In 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 42, pp. 1-14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)


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@InProceedings{dibbelt_et_al:OASIcs.ATMOS.2014.1,
  author =	{Dibbelt, Julian and Strasser, Ben and Wagner, Dorothea},
  title =	{{Delay-Robust Journeys in Timetable Networks with Minimum Expected Arrival Time}},
  booktitle =	{14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{1--14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-75-0},
  ISSN =	{2190-6807},
  year =	{2014},
  volume =	{42},
  editor =	{Funke, Stefan and Mihal\'{a}k, Mat\'{u}s},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2014.1},
  URN =		{urn:nbn:de:0030-drops-47488},
  doi =		{10.4230/OASIcs.ATMOS.2014.1},
  annote =	{Keywords: Algorithms, Optimization, Delay-robustness, Route planning, Public transportation}
}
Document
Speed-Consumption Tradeoff for Electric Vehicle Route Planning

Authors: Moritz Baum, Julian Dibbelt, Lorenz Hübschle-Schneider, Thomas Pajor, and Dorothea Wagner

Published in: OASIcs, Volume 42, 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (2014)


Abstract
We study the problem of computing routes for electric vehicles (EVs) in road networks. Since their battery capacity is limited, and consumed energy per distance increases with velocity, driving the fastest route is often not desirable and may even be infeasible. On the other hand, the energy-optimal route may be too conservative in that it contains unnecessary detours or simply takes too long. In this work, we propose to use multicriteria optimization to obtain Pareto sets of routes that trade energy consumption for speed. In particular, we exploit the fact that the same road segment can be driven at different speeds within reasonable intervals. As a result, we are able to provide routes with low energy consumption that still follow major roads, such as freeways. Unfortunately, the size of the resulting Pareto sets can be too large to be practical. We therefore also propose several nontrivial techniques that can be applied on-line at query time in order to speed up computation and filter insignificant solutions from the Pareto sets. Our extensive experimental study, which uses a real-world energy consumption model, reveals that we are able to compute diverse sets of alternative routes on continental networks that closely resemble the exact Pareto set in just under a second---several orders of magnitude faster than the exhaustive algorithm.

Cite as

Moritz Baum, Julian Dibbelt, Lorenz Hübschle-Schneider, Thomas Pajor, and Dorothea Wagner. Speed-Consumption Tradeoff for Electric Vehicle Route Planning. In 14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 42, pp. 138-151, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)


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@InProceedings{baum_et_al:OASIcs.ATMOS.2014.138,
  author =	{Baum, Moritz and Dibbelt, Julian and H\"{u}bschle-Schneider, Lorenz and Pajor, Thomas and Wagner, Dorothea},
  title =	{{Speed-Consumption Tradeoff for Electric Vehicle Route Planning}},
  booktitle =	{14th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems},
  pages =	{138--151},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-75-0},
  ISSN =	{2190-6807},
  year =	{2014},
  volume =	{42},
  editor =	{Funke, Stefan and Mihal\'{a}k, Mat\'{u}s},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2014.138},
  URN =		{urn:nbn:de:0030-drops-47583},
  doi =		{10.4230/OASIcs.ATMOS.2014.138},
  annote =	{Keywords: electric vehicles, shortest paths, route planning, bicriteria optimization, algorithm engineering}
}
Document
Get started imminently: Using tutorials to accelerate learning in automated static analysis

Authors: Jan-Peter Ostberg and Stefan Wagner

Published in: OASIcs, Volume 28, 2012 Imperial College Computing Student Workshop


Abstract
Static analysis can be a valuable quality assurance technique as it can find problems by analysing the source code of a system without executing it. Getting used to a static analysis tool, however, can easily take several hours or even days. In particular, understanding the warnings issued by the tool and rooting out the false positives is time consuming. This lowers the benefits of static analysis and demotivates developers in using it. Games solve this problem by offering a tutorial. Those tutorials are integrated in the setting of the game and teach the basic mechanics of the game. Often it is possible to repeat or pick topics of interest. We transfer this pattern to static analysis lowering the initial barrier of using it as well as getting an understanding of software quality spread out to more people. In this paper we propose a research strategy starting with a piloting period in which we will gather information about the questions static analysis users have as well as hone our answers to these questions. These results will be integrated into the prototype. We will evaluate our work then by comparing the fix times of user using the original tool versus our tool.

Cite as

Jan-Peter Ostberg and Stefan Wagner. Get started imminently: Using tutorials to accelerate learning in automated static analysis. In 2012 Imperial College Computing Student Workshop. Open Access Series in Informatics (OASIcs), Volume 28, pp. 109-115, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)


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@InProceedings{ostberg_et_al:OASIcs.ICCSW.2012.109,
  author =	{Ostberg, Jan-Peter and Wagner, Stefan},
  title =	{{Get started imminently: Using tutorials to accelerate learning in automated static analysis}},
  booktitle =	{2012 Imperial College Computing Student Workshop},
  pages =	{109--115},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-48-4},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{28},
  editor =	{Jones, Andrew V.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.ICCSW.2012.109},
  URN =		{urn:nbn:de:0030-drops-37739},
  doi =		{10.4230/OASIcs.ICCSW.2012.109},
  annote =	{Keywords: static analysis, motivation, usability, empirical research, gamification}
}
Document
Deterministic boundary recongnition and topology extraction for large sensor networks

Authors: Sándor Fekete, Alexander Kröller, Dennis Pfisterer, and Stefan Fischer

Published in: Dagstuhl Seminar Proceedings, Volume 5361, Algorithmic Aspects of Large and Complex Networks (2006)


Abstract
We present a new framework for the crucial challenge of self-organization of a large sensor network. The basic scenario can be described as follows: Given a large swarm of immobile sensor nodes that have been scattered in a polygonal region, such as a street network. Nodes have no knowledge of size or shape of the environment or the position of other nodes. Moreover, they have no way of measuring coordinates, geometric distances to other nodes, or their direction. Their only way of interacting with other nodes is to send or to receive messages from any node that is within communication range. The objective is to develop algorithms and protocols that allow self-organization of the swarm into large-scale structures that reflect the structure of the street network, setting the stage for global routing, tracking and guiding algorithms. Our algorithms work in two stages: boundary recognition and topology extraction. All steps are strictly deterministic, yield fast distributed algorithms, and make no assumption on the distribution of nodes in the environment, other than sufficient density.

Cite as

Sándor Fekete, Alexander Kröller, Dennis Pfisterer, and Stefan Fischer. Deterministic boundary recongnition and topology extraction for large sensor networks. In Algorithmic Aspects of Large and Complex Networks. Dagstuhl Seminar Proceedings, Volume 5361, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2006)


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@InProceedings{fekete_et_al:DagSemProc.05361.6,
  author =	{Fekete, S\'{a}ndor and Kr\"{o}ller, Alexander and Pfisterer, Dennis and Fischer, Stefan},
  title =	{{Deterministic boundary recongnition and topology extraction for large sensor networks}},
  booktitle =	{Algorithmic Aspects of Large and Complex Networks},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2006},
  volume =	{5361},
  editor =	{Stefano Leonardi and Friedhelm Meyer auf der Heide and Dorothea Wagner},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.05361.6},
  URN =		{urn:nbn:de:0030-drops-5632},
  doi =		{10.4230/DagSemProc.05361.6},
  annote =	{Keywords: Distributed algorithms, sensor networks, boundary recognition, topology extraction}
}
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