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Schmidt, Christiane
Publications (10 of 16) Show all publications
Josefsson, B., Polishchuk, T., Polishchuk, V. & Schmidt, C. (2019). A Step Towards Remote Tower Center Deployment: Optimizing Staff Scheduling. Journal of Air Transportation, 27(3)
Open this publication in new window or tab >>A Step Towards Remote Tower Center Deployment: Optimizing Staff Scheduling
2019 (English)In: Journal of Air Transportation, E-ISSN 2380-9450, Vol. 27, no 3Article in journal (Refereed) Published
Abstract [en]

Remote tower service is one of the technological and operational solutions delivered for deployment by the Single European Sky Air Traffic Management Research Program. This new concept fundamentally changes how operators provide air traffic services as it becomes possible to control several airports from a single remote center. In such settings, an air traffic controller works at a so-called multiple position in the remote center; that is, he/she handles two or more airports from one remote tower module, that is, the controller working position. In this paper, an optimization framework is presented for traffic management at five Swedish airports that were chosen for remote operation using a remote tower center designed to serve a number of airports. The problems experienced with real airport schedules are highlighted, and optimal assignments of the airports to the remote tower modules are presented. Both scheduled traffic and special (nonscheduled) traffic at these five airports are considered.

Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics, 2019
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-161307 (URN)10.2514/1.D0125 (DOI)
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-11-04Bibliographically approved
Daescu, O., Friedrichs, S., Malik, H., Polishchuk, V. & Schmidt, C. (2019). Altitude Terrain Guarding and Guarding Uni-Monotone Polygons. Computational geometry
Open this publication in new window or tab >>Altitude Terrain Guarding and Guarding Uni-Monotone Polygons
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2019 (English)In: Computational geometry, ISSN 0925-7721, E-ISSN 1879-081XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

We present an optimal, linear-time algorithm for the following version of terrain guarding: given a 1.5D terrain and a horizontal line, place the minimum number of guards on the line to see all of the terrain. We prove that the cardinality of the minimum guard set coincides with the cardinality of a maximum number of “witnesses”, i.e., terrain points, no two of which can be seen by a single guard. We show that our results also apply to the Art Gallery problem in “monotone mountains”, i.e., x-monotone polygons with a single edge as one of the boundary chains. This means that any monotone mountain is “perfect” (its guarding number is the same as its witness number); we thus establish the first non-trivial class of perfect polygons.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Terrain Guarding Problem, Art Gallery Problem, Altitude Terrain Guarding Problem, Perfect Polygons, Monotone Polygons, Uni-monotone Polygons, Monotone Mountains
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-161302 (URN)
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2020-01-17Bibliographically approved
Peterson, A., Polishchuk, V. & Schmidt, C. (2019). Applying Geometric Thick Paths to Compute the Maximum Number of Additional Train Paths in a Railway Timetable. In: : . Paper presented at Rail Norrköping.
Open this publication in new window or tab >>Applying Geometric Thick Paths to Compute the Maximum Number of Additional Train Paths in a Railway Timetable
2019 (English)Conference paper, Published paper (Refereed)
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-161305 (URN)
Conference
Rail Norrköping
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-10-28
Sáez, R., Prats, X., Polishchuk, T., Polishchuk, V. & Schmidt, C. (2019). Automation for Separation with CDOs: Dynamic Aircraft Arrival Routes. In: : . Paper presented at ATM Seminar.
Open this publication in new window or tab >>Automation for Separation with CDOs: Dynamic Aircraft Arrival Routes
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2019 (English)Conference paper, Published paper (Refereed)
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-161304 (URN)
Conference
ATM Seminar
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-11-04
Peterson, A., Wahlborg, M., Häll, C. H., Schmidt, C., Kordnejad, B., Warg, J., . . . Lidén, T. (2019). Deliverable D 3.1: Analysis of the gap between daily timetable and operational traffic.
Open this publication in new window or tab >>Deliverable D 3.1: Analysis of the gap between daily timetable and operational traffic
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2019 (English)Report (Other academic)
Abstract [en]

Fr8Rail II/Work-Package 3 Real-time network management and improved methods for timetable planning addresses the problem to improve capacity and punctuality in the railway system by developing concepts and methods for tactical planning and operational traffic. In this report the state-of-the-art has been summarised.

The aim of the project is to:

  • Propose concepts and methods that improve the annual and short-term timetable planning.
  • Demonstrate how the proposed timetable planning concepts improve the prerequisites for real-time network management.
  • Develop methods and tools that can reduce inefficiencies in real time network management.

An important aspect is to improve the coordination between yards/terminals and the line network, and between Infrastructure Manager, Yard Managers, and freight Rail Undertakings.

We motivate our research by the current situation in Sweden, which is characterised by low on-time performance for freight trains, dense and heterogenous traffic on the major railway lines, and a rigid annual timetabling process, which is non-suitable for short-term changes. We believe that better tools for network planning and management on tactical and operational level can help to connect planning and operational processes.

Aiming for improvements of the operational traffic, there is a need for systematic development of methods applied at several planning horizons, based on both simulation and optimization techniques. Close to operation fast methods are needed, for example, based on meta-heuristics.

The maintenance planning process and improvement potential have been described. This is a new piece of the puzzle and it is important to close the gap between timetable planning and operational traffic. The different planning processes at the Infrastructure Manager, the Rail Undertakings and the Maintenance Contractors should be aligned.

When developing new approaches for computational decision-support tools for real-time network management, it is important — but very challenging — to evaluate and benchmark with existing software tools. We also observe that the research stream on computational decision-support and algorithm development for railway traffic management has not yet been sufficiently merged with the corresponding research stream focusing on aspects of human computer interaction.

Publisher
p. 88
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-163489 (URN)
Projects
Shift2Rail/Fr8Rail II
Funder
EU, Horizon 2020, H2020-S2R-CFM-IP5-01-2018
Note

Project lead: Magnus Wahlborg 

Editor: Anders Peterson

Available from: 2020-02-05 Created: 2020-02-05 Last updated: 2020-02-06Bibliographically approved
Aichholzer, O., Akitaya, H., Cheung, K., Demaine, E., Demaine, M., Fekete, S., . . . Schmidt, C. (2019). Folding Polyominoes with Holes into a Cube. In: : . Paper presented at Canadian Conference on Computational Geoemtry.
Open this publication in new window or tab >>Folding Polyominoes with Holes into a Cube
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2019 (English)Conference paper, Published paper (Refereed)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-161301 (URN)
Conference
Canadian Conference on Computational Geoemtry
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-10-28
Andersson Granberg, T., Polishchuk, T., Polishchuk, V. & Schmidt, C. (2019). Integer Programming-Based Airspace Sectorization for Terminal Maneuvering Areas with Convex Sectors. Journal of Air Transportation, 27(4)
Open this publication in new window or tab >>Integer Programming-Based Airspace Sectorization for Terminal Maneuvering Areas with Convex Sectors
2019 (English)In: Journal of Air Transportation, E-ISSN 2380-9450, Vol. 27, no 4Article in journal (Refereed) Published
Abstract [en]

In this paper an airspace sectorization framework for terminal maneuvering areas based on mixed integer programming is presented. It incorporates an airspace complexity representation, as well as various constraints on the sectors’ geometry, for example, the requirement that points demanding increased attention from air traffic controllers should lie in the sector’s interior to allow for enough time to resolve possible conflicts. The method can enforce convex sectors. In contrast to earlier integer/constraint programming approaches, which used synthesis methods with variables per elementary airspace piece that were glued together to form sectors, the integer programming formulation uses a variable per potential edge on the sector boundary. It is also the first step toward an integrated design of routes, the resulting complexity, and a sectorization. This paper presents results for Stockholm Arlanda airport and compares the integer programming results to convex sectorizations obtained by enumerating all possible topologies for a given number of sectors. This yields a proof-of-concept for the application of this highly flexible approach to terminal maneuvering areas.

Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics, 2019
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-161306 (URN)10.2514/1.D0148 (DOI)
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2020-01-08Bibliographically approved
Friedrichs, S., Polishchuk, V. & Schmidt, C. (2018). Altitude Terrain Guarding and Guarding Uni-Monotone Polygons. In: : . Paper presented at European Workshop on Computational Geometry.
Open this publication in new window or tab >>Altitude Terrain Guarding and Guarding Uni-Monotone Polygons
2018 (English)Conference paper, Published paper (Refereed)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-161309 (URN)
Conference
European Workshop on Computational Geometry
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-10-28
Cannon, S., Fai, T., Iwerks, J., Leopold, U. & Schmidt, C. (2018). Combinatorics and complexity of guarding polygons with edge and point 2-transmitters. Computational geometry, 68, 89-100
Open this publication in new window or tab >>Combinatorics and complexity of guarding polygons with edge and point 2-transmitters
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2018 (English)In: Computational geometry, ISSN 0925-7721, E-ISSN 1879-081X, Vol. 68, p. 89-100Article in journal (Refereed) Published
Abstract [en]

We consider a generalization of the classical Art Gallery Problem, where instead of a light source, the guards, called k-transmitters, model a wireless device with a signal that can pass through at most k walls. We show it is NP-hard to compute a minimum cover of point 2-transmitters, point k-transmitters, and edge 2-transmitters in a simple polygon. The point 2-transmitter result extends to orthogonal polygons. In addition, we give necessity and sufficiency results for the number of edge 2-transmitters in general, monotone, orthogonal monotone, and orthogonal polygons.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Art Gallery Problem, 2-Transmitter, k-Transmitter, NP-hardness
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-142557 (URN)10.1016/j.comgeo.2017.06.004 (DOI)000415778300008 ()2-s2.0-85020645869 (Scopus ID)
Note

Funding agencies: AMS

Available from: 2017-10-31 Created: 2017-10-31 Last updated: 2019-01-25Bibliographically approved
Wahlborg, M., Peterson, A., Gruosso, L., Schmidt, C. & Jalili, L. (2018). D3.1 – Final pre-study for an improved methodology for timetable planning including state-of-the-art and future work plan.
Open this publication in new window or tab >>D3.1 – Final pre-study for an improved methodology for timetable planning including state-of-the-art and future work plan
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2018 (English)Report (Other academic)
Alternative title[en]
D3.1 Improved timetable planning
Abstract [en]

In ARCC project work package 3, research and innovation activities have been done to identify areas with a need for improved timetable planning methods and outline how new methods can be developed and implemented.

Improved timetable planning scope were described and there was an activity to connect to other relevant Shift2Rail projects. An workshop was organised in Stockholm 2018-05-29.

State of the art in practice was described for timetable planning in Sweden, UIC 406 method and Ansaldo STS Traffic management systems. Also state of the art in algorithms was described.

Future work plan research needs areas are:

1. Understanding of various goals for timetabling and how they co-variate

2. Residual capacity

3. Connection and coordination of the planning processes

4. Connection and coordination of the yard/terminal planning and network planning

5. Integration of freight trains into the timetable, focusing on short-term and ad-hoc

6. Integration of maintenance scheduling and timetabling, at all planning stages

7. Improved decision support for handeling of deviations from timetable in operations

8. Features of planning tools, and implementation of automatized timetabling

Publisher
p. 66
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:liu:diva-160801 (URN)
Projects
Automated Rail Cargo Consortium: Rail freight automation research activities to boost levels of quality, efficiency and cost effectiveness in all areas of rail freight operations
Funder
EU, Horizon 2020, H2020 – 730813
Note

Peterson är "main editor".

Övriga författare är "Medarbetare/bidragsgivare".

Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-10-08Bibliographically approved
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