30 Search Results for "Sauer, Jonas"

Volume

OASIcs, Volume 137

25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

ATMOS 2025, September 18-19, 2025, Warsaw, Poland

Editors: Jonas Sauer and Marie Schmidt

Document
Complete Volume
DOI: 10.4230/OASIcs.ATMOS.2025
OASIcs, Volume 137, ATMOS 2025, Complete Volume

Authors: Jonas Sauer and Marie Schmidt

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
OASIcs, Volume 137, ATMOS 2025, Complete Volume
Cite as

25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 1-342, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@Proceedings{sauer_et_al:OASIcs.ATMOS.2025,
  title =	{{OASIcs, Volume 137, ATMOS 2025, Complete Volume}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{1--342},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025},
  URN =		{urn:nbn:de:0030-drops-248922},
  doi =		{10.4230/OASIcs.ATMOS.2025},
  annote =	{Keywords: OASIcs, Volume 137, ATMOS 2025, Complete Volume}
}
Document
Front Matter
DOI: 10.4230/OASIcs.ATMOS.2025.0
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Jonas Sauer and Marie Schmidt

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

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

25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 0:i-0:xii, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{sauer_et_al:OASIcs.ATMOS.2025.0,
  author =	{Sauer, Jonas and Schmidt, Marie},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{0:i--0:xii},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.0},
  URN =		{urn:nbn:de:0030-drops-248915},
  doi =		{10.4230/OASIcs.ATMOS.2025.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.10
A Genetic Algorithm for Multi-Capacity Fixed-Charge Flow Network Design

Authors: Caleb Eardley, Dalton Gomez, Ryan Dupuis, Michael Papadopoulos, and Sean Yaw

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
The Multi-Capacity Fixed-Charge Network Flow (MC-FCNF) problem, a generalization of the Fixed-Charge Network Flow problem, aims to assign capacities to edges in a flow network such that a target amount of flow can be hosted at minimum cost. The cost model for both problems dictates that the fixed cost of an edge is incurred for any non-zero amount of flow hosted by that edge. This problem naturally arises in many areas including infrastructure design, transportation, telecommunications, and supply chain management. The MC-FCNF problem is NP-Hard, so solving large instances using exact techniques is impractical. This paper presents a genetic algorithm designed to quickly find high-quality flow solutions to the MC-FCNF problem. The genetic algorithm uses a novel solution representation scheme that eliminates the need to repair invalid flow solutions, which is an issue common to many other genetic algorithms for the MC-FCNF problem. The genetic algorithm’s utility is demonstrated with an evaluation using real-world CO₂ capture, transportation, and storage infrastructure design data. The evaluation results highlight the genetic algorithm’s potential for solving large-scale network design problems.
Cite as

Caleb Eardley, Dalton Gomez, Ryan Dupuis, Michael Papadopoulos, and Sean Yaw. A Genetic Algorithm for Multi-Capacity Fixed-Charge Flow Network Design. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 10:1-10:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{eardley_et_al:OASIcs.ATMOS.2025.10,
  author =	{Eardley, Caleb and Gomez, Dalton and Dupuis, Ryan and Papadopoulos, Michael and Yaw, Sean},
  title =	{{A Genetic Algorithm for Multi-Capacity Fixed-Charge Flow Network Design}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{10:1--10:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.10},
  URN =		{urn:nbn:de:0030-drops-247661},
  doi =		{10.4230/OASIcs.ATMOS.2025.10},
  annote =	{Keywords: Fixed-Charge Network Flow, Genetic Algorithm, Matheuristic, Infrastructure Design}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.13
Multi-Criteria Route Planning with Little Regret

Authors: Carina Truschel and Sabine Storandt

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
Multi-criteria route planning arises naturally in real-world navigation scenarios where users care about more than just one objective - such as minimizing travel time while also avoiding steep inclines or unpaved surfaces or toll routes. To capture the possible trade-offs between competing criteria, many algorithms compute the set of Pareto-optimal paths, which are paths that are not dominated by others with respect to the considered cost vectors. However, the number of Pareto-optimal paths can grow exponentially with the size of the input graph. This leads to significant computational overhead and results in large output sets that overwhelm users with too many alternatives. In this work, we present a technique based on the notion of regret minimization that efficiently filters the Pareto set during or after the search to a subset of specified size. Regret minimizing algorithms identify such a representative solution subset by considering how any possible user values any subset with respect to the objectives. We prove that regret-based filtering provides us with quality guarantees for the two main query types that are considered in the context of multi-criteria route planning, namely constrained shortest path queries and personalized path queries. Furthermore, we design a novel regret minimization algorithm that works for any number of criteria, is easy to implement and produces solutions with much smaller regret value than the most commonly used baseline algorithm. We carefully describe how to incorporate our regret minimization algorithm into existing route planning techniques to drastically reduce their running times and space consumption, while still returning paths that are close-to-optimal.
Cite as

Carina Truschel and Sabine Storandt. Multi-Criteria Route Planning with Little Regret. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 13:1-13:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{truschel_et_al:OASIcs.ATMOS.2025.13,
  author =	{Truschel, Carina and Storandt, Sabine},
  title =	{{Multi-Criteria Route Planning with Little Regret}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{13:1--13:20},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.13},
  URN =		{urn:nbn:de:0030-drops-247698},
  doi =		{10.4230/OASIcs.ATMOS.2025.13},
  annote =	{Keywords: Pareto-optimality, Regret minimization, Contraction Hierarchies}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.9
Speed-Aware Network Design: A Parametric Optimization Approach

Authors: Ugo Rosolia, Marc Bataillou Almagro, George Iosifidis, Martin Gross, and Georgios Paschos

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
Network design problems have been studied from the 1950s, as they can be used in a wide range of real-world applications, e.g., design of communication and transportation networks. In classical network design problems, the objective is to minimize the cost of routing the demand flow through a graph. In this paper, we introduce a generalized version of such a problem, where the objective is to tradeoff routing costs and delivery speed; we introduce the concept of speed-coverage, which is defined as the number of unique items that can be sent to destinations in less than 1-day. Speed-coverage is a function of both the network design and the inventory stored at origin nodes, e.g., an item can be delivered in 1-day if it is in-stock at an origin that can reach a destination within 24 hours. Modeling inventory is inherently complex, since inventory coverage is described by an integer function with a large number of points (exponential to the number of origin sites), each one to be evaluated using historical data. To bypass this complexity, we first leverage a parametric optimization approach, which converts the non-linear joint routing and speed-coverage optimization problem into an equivalent mixed-integer linear program. Then, we propose a sampling strategy to avoid evaluating all the points of the speed-coverage function. The proposed method is evaluated on a series of numerical tests with representative scenarios and network sizes. We show that when considering the routing costs and monetary gains resulting from speed-coverage, our approach outperforms the baseline by 8.36% on average.
Cite as

Ugo Rosolia, Marc Bataillou Almagro, George Iosifidis, Martin Gross, and Georgios Paschos. Speed-Aware Network Design: A Parametric Optimization Approach. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 9:1-9:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{rosolia_et_al:OASIcs.ATMOS.2025.9,
  author =	{Rosolia, Ugo and Almagro, Marc Bataillou and Iosifidis, George and Gross, Martin and Paschos, Georgios},
  title =	{{Speed-Aware Network Design: A Parametric Optimization Approach}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{9:1--9:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.9},
  URN =		{urn:nbn:de:0030-drops-247655},
  doi =		{10.4230/OASIcs.ATMOS.2025.9},
  annote =	{Keywords: Network Design, Transportation Networks, Mixed-Integer Programming, Speed-Coverage, Parametric Optimization}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.11
Design of Distance Tariffs in Public Transport

Authors: Philine Schiewe, Anita Schöbel, and Reena Urban

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
Setting the ticket prices is a crucial decision in public transport. Its basis, relevant for all related questions, such as dynamic prices or prices for different passenger groups, is the underlying fare strategy. Popular fare strategies are based on zones or on distances. Transitions from one fare strategy to another occur frequently, e.g., if public transport operators are joined to a larger association, or if structural decisions in a region have taken place. In this paper we report practically relevant issues when a fare structure should be changed to a distance tariff, a problem frequently arising when a ticket system based on mobile devices is introduced. We present mixed-integer linear programs for finding the parameters of a distance tariff, analyze rounding properties, and reflect how the change in revenue for the operator and the number of highly affected passengers can be controlled. Additionally, we evaluate the developed models experimentally.
Cite as

Philine Schiewe, Anita Schöbel, and Reena Urban. Design of Distance Tariffs in Public Transport. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 11:1-11:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{schiewe_et_al:OASIcs.ATMOS.2025.11,
  author =	{Schiewe, Philine and Sch\"{o}bel, Anita and Urban, Reena},
  title =	{{Design of Distance Tariffs in Public Transport}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{11:1--11:20},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.11},
  URN =		{urn:nbn:de:0030-drops-247670},
  doi =		{10.4230/OASIcs.ATMOS.2025.11},
  annote =	{Keywords: public transport, fare strategy, distance tariff}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.14
Using A* for Optimal Train Routing on Moving Block Systems

Authors: Stefan Engels and Robert Wille

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
Modern control systems based on Moving Block allow for shorter headways and higher capacity on existing railway infrastructure. At the same time, few algorithms for optimal routing on networks equipped with such modern control systems exist. Previous methods rely on Mixed Integer Linear Programming (MILP) and face a trade-off between model size and accuracy, especially considering comparably complex and nonlinear headway constraints as well as train dynamics. With this work, we propose a complementary approach based on A*. Under a reasonable and easy assumption on train driver behavior, we propose a solution encoding and state space that is flexible concerning the choice of search algorithm and the modeling detail. The applicability is showcased on a small benchmark set. The implementation is available open-source as part of the Munich Train Control Toolkit (MTCT) on GitHub at https://github.com/cda-tum/mtct.
Cite as

Stefan Engels and Robert Wille. Using A* for Optimal Train Routing on Moving Block Systems. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 14:1-14:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{engels_et_al:OASIcs.ATMOS.2025.14,
  author =	{Engels, Stefan and Wille, Robert},
  title =	{{Using A* for Optimal Train Routing on Moving Block Systems}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{14:1--14:18},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.14},
  URN =		{urn:nbn:de:0030-drops-247701},
  doi =		{10.4230/OASIcs.ATMOS.2025.14},
  annote =	{Keywords: ETCS, Train Routing, Moving Block, A*, Munich Train Control Toolkit}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.12
Separator-Based Alternative Paths in Customizable Contraction Hierarchies

Authors: Scott Bacherle, Thomas Bläsius, and Michael Zündorf

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
We propose an algorithm for computing alternatives to the shortest path in a road network, based on the speed-up technique CCH (customizable contraction hierarchy). Computing alternative paths is a well-studied problem, motivated by the fact that route-planning applications benefit from presenting different high-quality options the user can choose from. Another crucial feature of modern routing applications is the inclusion of live traffic, which requires speed-up techniques that allow efficient metric updates. Besides CCH, the other speed-up technique supporting metric updates is CRP (customizable route planning). Of the two, CCH is the more modern solution with the advantages of providing faster queries and being substantially simpler to implement efficiently. However, so far, CCH has been lacking a way of computing alternative paths. While for CRP, the commonly used plateau method for computing alternatives can be applied, this is not so straightforward for CCH. With this paper, we make CCH a viable option for alternative paths, by proposing a new separator-based approach to computing alternative paths that works hand-in-hand with the CCH data structure. With our experiments, we demonstrate that CCH can indeed be used to compute alternative paths efficiently. With this, we provide an alternative to CRP that is simpler and has lower query times.
Cite as

Scott Bacherle, Thomas Bläsius, and Michael Zündorf. Separator-Based Alternative Paths in Customizable Contraction Hierarchies. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 12:1-12:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{bacherle_et_al:OASIcs.ATMOS.2025.12,
  author =	{Bacherle, Scott and Bl\"{a}sius, Thomas and Z\"{u}ndorf, Michael},
  title =	{{Separator-Based Alternative Paths in Customizable Contraction Hierarchies}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{12:1--12:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.12},
  URN =		{urn:nbn:de:0030-drops-247685},
  doi =		{10.4230/OASIcs.ATMOS.2025.12},
  annote =	{Keywords: Alternative routes, realistic road networks, customizable contraction hierarchies, route planning, shortest paths}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.8
Refined Integer Programs and Polyhedral Results for the Target Visitation Problem

Authors: Sven Mallach

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
The Target Visitation Problem (TVP) combines the Traveling Salesman Problem and the Linear Ordering Problem, and thus serves as a natural model for route planning applications where both the travel costs and the order of the sites to visit matter. More precisely, in addition to the costs that apply for the selected links connecting two subsequently visited sites, the relative urgency of visiting one site before another is quantified and taken into account. In this article, we present refined integer linear programming formulations for the TVP, along with clarifications and extensions regarding the description of the polytopes associated with their feasible solution sets by a minimal set of linear equations and facet-defining inequalities. The practical effectiveness of exploiting the proposed improvements by means of a branch-and-cut algorithm is demonstrated in a computational study. In addition, we report the optimal values for some previously unsolved instances.
Cite as

Sven Mallach. Refined Integer Programs and Polyhedral Results for the Target Visitation Problem. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 8:1-8:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{mallach:OASIcs.ATMOS.2025.8,
  author =	{Mallach, Sven},
  title =	{{Refined Integer Programs and Polyhedral Results for the Target Visitation Problem}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{8:1--8:17},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.8},
  URN =		{urn:nbn:de:0030-drops-247647},
  doi =		{10.4230/OASIcs.ATMOS.2025.8},
  annote =	{Keywords: Route planning, Transportation, Logistics, Traveling salesman problem, Linear ordering problem, Polyhedral Combinatorics, Branch-and-cut, Integer Programming, Linear programming}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.1
The Fair Periodic Assignment Problem

Authors: Rolf Nelson van Lieshout and Bartholomeüs Theodorus Cornelis van Rossum

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
We study the periodic assignment problem, in which a set of periodically repeating tasks must be assigned to workers within a repeating schedule. The classical efficiency objective is to minimize the number of workers required to operate the schedule. We propose a 𝒪(n log n) algorithm to solve this problem. Next, we formalize a notion of fairness among workers, and impose that each worker performs the same work over time. We analyze the resulting trade-off between efficiency and fairness, showing that the price of fairness is at most one extra worker, and that such a fair solution can always be found using the Nearest Neighbor heuristic. We characterize all instances that admit a solution that is both fair and efficient, and use this result to develop a 𝒪(n log n) exact algorithm for the fair periodic assignment problem. Finally, we show that allowing aperiodic schedules never reduces the price of fairness.
Cite as

Rolf Nelson van Lieshout and Bartholomeüs Theodorus Cornelis van Rossum. The Fair Periodic Assignment Problem. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 1:1-1:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{vanlieshout_et_al:OASIcs.ATMOS.2025.1,
  author =	{van Lieshout, Rolf Nelson and van Rossum, Bartholome\"{u}s Theodorus Cornelis},
  title =	{{The Fair Periodic Assignment Problem}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{1:1--1:16},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.1},
  URN =		{urn:nbn:de:0030-drops-247574},
  doi =		{10.4230/OASIcs.ATMOS.2025.1},
  annote =	{Keywords: Cyclic scheduling, Fairness, Traveling Salesman Problem}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.2
A Geometric Approach to Integrated Periodic Timetabling and Passenger Routing

Authors: Fabian Löbel and Niels Lindner

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
We offer a geometric perspective on the problem of integrated periodic timetabling and passenger routing in public transport. Inside the space of periodic tensions, we single out those regions, where the same set of paths provides shortest passenger routes. This results in a polyhedral subdivision, which we combine with the known decomposition by polytropes. On each maximal region of the common refinement, the integrated problem is solvable in polynomial time. We transform these insights into a new geometry-driven primal heuristic, integrated tropical neighborhood search (ITNS). Computationally, we compare implementations of ITNS and the integrated (restricted) modulo network simplex algorithm on the TimPassLib benchmark set, and contribute better solutions in terms of total travel time for all but one of the twenty-five instances for which a proven optimal solution is not yet known.
Cite as

Fabian Löbel and Niels Lindner. A Geometric Approach to Integrated Periodic Timetabling and Passenger Routing. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 2:1-2:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{lobel_et_al:OASIcs.ATMOS.2025.2,
  author =	{L\"{o}bel, Fabian and Lindner, Niels},
  title =	{{A Geometric Approach to Integrated Periodic Timetabling and Passenger Routing}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{2:1--2:19},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.2},
  URN =		{urn:nbn:de:0030-drops-247580},
  doi =		{10.4230/OASIcs.ATMOS.2025.2},
  annote =	{Keywords: Periodic Timetabling, Passenger Routing, Polyhedral Complexes}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.3
Directed Temporal Tree Realization for Periodic Public Transport: Easy and Hard Cases

Authors: Julia Meusel, Matthias Müller-Hannemann, and Klaus Reinhardt

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
We study the complexity of the directed periodic temporal graph realization problem. This work is motivated by the design of periodic schedules in public transport with constraints on the quality of service. Namely, we require that the fastest path between (important) pairs of vertices is upper bounded by a specified maximum duration, encoded in an upper distance matrix D. While previous work has considered the undirected version of the problem, the application in public transport schedule design requires the flexibility to assign different departure times to the two directions of an edge. A problem instance can only be feasible if all values of the distance matrix are at least shortest path distances. However, the task of realizing exact fastest path distances in a periodic temporal graph is often too restrictive. Therefore, we introduce a minimum slack parameter k that describes a lower bound on the maximum allowed waiting time on each path. We concentrate on tree topologies and provide a full characterization of the complexity landscape with respect to the period Δ and the minimum slack parameter k, showing a sharp threshold between NP-complete cases and cases which are always realizable. We also provide hardness results for the special case of period Δ = 2 for general directed and undirected graphs.
Cite as

Julia Meusel, Matthias Müller-Hannemann, and Klaus Reinhardt. Directed Temporal Tree Realization for Periodic Public Transport: Easy and Hard Cases. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 3:1-3:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{meusel_et_al:OASIcs.ATMOS.2025.3,
  author =	{Meusel, Julia and M\"{u}ller-Hannemann, Matthias and Reinhardt, Klaus},
  title =	{{Directed Temporal Tree Realization for Periodic Public Transport: Easy and Hard Cases}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{3:1--3:22},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.3},
  URN =		{urn:nbn:de:0030-drops-247594},
  doi =		{10.4230/OASIcs.ATMOS.2025.3},
  annote =	{Keywords: Periodic timetabling, service quality, temporal graph, graph realization, complexity}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.4
Visualization of Event Graphs for Train Schedules

Authors: Johann Hartleb, Marie Schmidt, Samuel Wolf, and Alexander Wolff

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
Train timetables can be represented as event graphs, where events correspond to a train passing through a location at a certain point in time. A visual representation of an event graph is important for many applications such as dispatching and (the development of) dispatching software. A common way to represent event graphs are time-space diagrams. In such a diagram, key locations are visualized on the y-axis and time on the x-axis of a coordinate system. A train’s movement is then represented as a connected sequence of line segments in this coordinate system. This visualization allows for an easy detection of infrastructure conflicts and safety distance violations. However, time-space diagrams are usually used only to depict event graphs that are restricted to corridors, where an obvious ordering of the locations exists. In this paper, we consider the visualization of general event graphs in time-space diagrams, where the challenge is to find an ordering of the locations that produces readable drawings. We argue that this means to minimize the number of turns, i.e., the total number of changes in y-direction. To this end, we establish a connection between this problem and Maximum Betweenness. Then we develop a preprocessing strategy to reduce the instance size. We also propose a parameterized algorithm and integer linear programming formulations. We experimentally evaluate the preprocessing strategy and the integer programming formulations on a real-world dataset. Our best algorithm solves every instance in the dataset in less than a second. This suggests that turn-optimal time-space diagrams can be computed in real time.
Cite as

Johann Hartleb, Marie Schmidt, Samuel Wolf, and Alexander Wolff. Visualization of Event Graphs for Train Schedules. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 4:1-4:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{hartleb_et_al:OASIcs.ATMOS.2025.4,
  author =	{Hartleb, Johann and Schmidt, Marie and Wolf, Samuel and Wolff, Alexander},
  title =	{{Visualization of Event Graphs for Train Schedules}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{4:1--4:20},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.4},
  URN =		{urn:nbn:de:0030-drops-247607},
  doi =		{10.4230/OASIcs.ATMOS.2025.4},
  annote =	{Keywords: Graph Drawing, Event Graphs, Integer Linear Programming, Parameterized Algorithms, Treewidth}
}
Document
DOI: 10.4230/OASIcs.ATMOS.2025.5
Throughput Maximization in a Scheduling Environment with Machine-Dependent Due-Dates

Authors: Shaul Rosner and Tami Tamir

Published in: OASIcs, Volume 137, 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)

Abstract
We consider a scheduling environment in which jobs are associated with machine-dependent due-dates. This natural setting arises in systems where clients' tolerance depends on the service provider. The objective is to maximize throughput, defined as the number of non-tardy jobs. The problem exhibits significant differences from previously studied scheduling models. We analyze its computational complexity both in general and for the special case of unit-length jobs. In the unit-length setting, we provide an optimal algorithm that also extends to cases with machine-dependent release times and machine-dependent weights (i.e., rewards depending on the machine that completes the job). For jobs with different lengths, we show that even the unweighted problem without release times, with only two different lengths, specifically, for all j, p_j ∈ {1,2}, is APX-hard. To isolate the role of machine-dependent due-dates in this hardness result, we present an optimal algorithm for the case where all p_j ∈ {1,2} and due-dates are not machine-dependent. This algorithm further extends to instances with a constant number of integer processing times.
Cite as

Shaul Rosner and Tami Tamir. Throughput Maximization in a Scheduling Environment with Machine-Dependent Due-Dates. In 25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025). Open Access Series in Informatics (OASIcs), Volume 137, pp. 5:1-5:10, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{rosner_et_al:OASIcs.ATMOS.2025.5,
  author =	{Rosner, Shaul and Tamir, Tami},
  title =	{{Throughput Maximization in a Scheduling Environment with Machine-Dependent Due-Dates}},
  booktitle =	{25th Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2025)},
  pages =	{5:1--5:10},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-404-8},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{137},
  editor =	{Sauer, Jonas and Schmidt, Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2025.5},
  URN =		{urn:nbn:de:0030-drops-247616},
  doi =		{10.4230/OASIcs.ATMOS.2025.5},
  annote =	{Keywords: Scheduling, Throughput maximization, Machine-dependent due-dates, Computational Complexity}
}
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