3 Search Results for "Duarte, José"

Document
DOI: 10.4230/OASIcs.ATMOS.2023.8
Fewer Trains for Better Timetables: The Price of Fixed Line Frequencies in the Passenger-Oriented Timetabling Problem

Authors: Pedro José Correia Duarte, Marie Schmidt, Dennis Huisman, and Lucas P. Veelenturf

Published in: OASIcs, Volume 115, 23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023)

Abstract
This paper introduces the Passenger-Oriented Timetabling problem with flexible frequencies (POT-flex) in the context of railway planning problems. POT-flex aims at creating feasible railway timetables minimising total perceived passenger travel time. The contribution of the POT-flex lies in its relaxation of the generally adopted assumption that line frequencies should be a fixed part of the input. Instead, we consider flexible line frequencies, encompassing a minimum and maximum frequency per line, allowing the timetabling model to decide on optimal line frequencies to obtain better solutions using fewer train services per line. We develop a mixed-integer programming formulation for POT-flex based on the Passenger-Oriented Timetabling (POT) formulation of [Polinder et al., 2021] and compare the performance of the new formulation against the POT formulation on three instances. We find that POT-flex allows to find feasible timetables in instances containing bottlenecks, and show improvements of up to 2% on the largest instance tested. These improvements highlight the cost that fixed line frequencies can have on timetabling.
Cite as

Pedro José Correia Duarte, Marie Schmidt, Dennis Huisman, and Lucas P. Veelenturf. Fewer Trains for Better Timetables: The Price of Fixed Line Frequencies in the Passenger-Oriented Timetabling Problem. In 23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023). Open Access Series in Informatics (OASIcs), Volume 115, pp. 8:1-8:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{correiaduarte_et_al:OASIcs.ATMOS.2023.8,
  author =	{Correia Duarte, Pedro Jos\'{e} and Schmidt, Marie and Huisman, Dennis and Veelenturf, Lucas P.},
  title =	{{Fewer Trains for Better Timetables: The Price of Fixed Line Frequencies in the Passenger-Oriented Timetabling Problem}},
  booktitle =	{23rd Symposium on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2023)},
  pages =	{8:1--8:18},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-302-7},
  ISSN =	{2190-6807},
  year =	{2023},
  volume =	{115},
  editor =	{Frigioni, Daniele and Schiewe, Philine},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2023.8},
  URN =		{urn:nbn:de:0030-drops-187695},
  doi =		{10.4230/OASIcs.ATMOS.2023.8},
  annote =	{Keywords: PESP, Passenger Oriented Timetabling, Perceived Travel Time}
}
Document
DOI: 10.4230/OASIcs.SLATE.2021.7
MUAHAH: Taking the Most out of Simple Conversational Agents

Authors: Leonor Llansol, João Santos, Luís Duarte, José Santos, Mariana Gaspar, Ana Alves, Hugo Gonçalo Oliveira, and Luísa Coheur

Published in: OASIcs, Volume 94, 10th Symposium on Languages, Applications and Technologies (SLATE 2021)

Abstract
Dialog engines based on multi-agent architectures usually select a single agent, deemed to be the most suitable for a given scenario or for responding to a specific request, and disregard the answers from all of the other available agents. In this work, we present a multi-agent plug-and-play architecture that: (i) enables the integration of different agents; (ii) includes a decision maker module, responsible for selecting a suitable answer out of the responses of different agents. As usual, a single agent can be chosen to provide the final answer, but the latter can also be obtained from the responses of several agents, according to a voting scheme. We also describe three case studies in which we test several agents and decision making strategies; and show how new agents and a new decision strategy can be easily plugged in and take advantage of this platform in different ways. Experimentation also confirms that considering several agents contributes to better responses.
Cite as

Leonor Llansol, João Santos, Luís Duarte, José Santos, Mariana Gaspar, Ana Alves, Hugo Gonçalo Oliveira, and Luísa Coheur. MUAHAH: Taking the Most out of Simple Conversational Agents. In 10th Symposium on Languages, Applications and Technologies (SLATE 2021). Open Access Series in Informatics (OASIcs), Volume 94, pp. 7:1-7:12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{llansol_et_al:OASIcs.SLATE.2021.7,
  author =	{Llansol, Leonor and Santos, Jo\~{a}o and Duarte, Lu{\'\i}s and Santos, Jos\'{e} and Gaspar, Mariana and Alves, Ana and Gon\c{c}alo Oliveira, Hugo and Coheur, Lu{\'\i}sa},
  title =	{{MUAHAH: Taking the Most out of Simple Conversational Agents}},
  booktitle =	{10th Symposium on Languages, Applications and Technologies (SLATE 2021)},
  pages =	{7:1--7:12},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-202-0},
  ISSN =	{2190-6807},
  year =	{2021},
  volume =	{94},
  editor =	{Queir\'{o}s, Ricardo and Pinto, M\'{a}rio and Sim\~{o}es, Alberto and Portela, Filipe and Pereira, Maria Jo\~{a}o},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2021.7},
  URN =		{urn:nbn:de:0030-drops-144248},
  doi =		{10.4230/OASIcs.SLATE.2021.7},
  annote =	{Keywords: Dialog systems, question answering, information retrieval, multi-agent}
}
Document
Vision Paper
DOI: 10.4230/LIPIcs.COSIT.2019.6
Modeling and Representing Real-World Spatio-Temporal Data in Databases (Vision Paper)

Authors: José Moreira, José Duarte, and Paulo Dias

Published in: LIPIcs, Volume 142, 14th International Conference on Spatial Information Theory (COSIT 2019)

Abstract
Research in general-purpose spatio-temporal databases has focused mainly on the development of data models and query languages. However, since spatio-temporal data are captured as snapshots, an important research question is how to compute and represent the spatial evolution of the data between observations in databases. Current methods impose constraints to ensure data integrity, but, in some cases, these constraints do not allow the methods to obtain a natural representation of the evolution of spatio-temporal phenomena over time. This paper discusses a different approach where morphing techniques are used to represent the evolution of spatio-temporal data in databases. First, the methods proposed in the spatio-temporal databases literature are presented and their main limitations are discussed with the help of illustrative examples. Then, the paper discusses the use of morphing techniques to handle spatio-temporal data, and the requirements and the challenges that must be investigated to allow the use of these techniques in databases. Finally, a set of examples is presented to compare the approaches investigated in this work. The need for benchmarking methodologies for spatio-temporal databases is also highlighted.
Cite as

José Moreira, José Duarte, and Paulo Dias. Modeling and Representing Real-World Spatio-Temporal Data in Databases (Vision Paper). In 14th International Conference on Spatial Information Theory (COSIT 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 142, pp. 6:1-6:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{moreira_et_al:LIPIcs.COSIT.2019.6,
  author =	{Moreira, Jos\'{e} and Duarte, Jos\'{e} and Dias, Paulo},
  title =	{{Modeling and Representing Real-World Spatio-Temporal Data in Databases}},
  booktitle =	{14th International Conference on Spatial Information Theory (COSIT 2019)},
  pages =	{6:1--6:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-115-3},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{142},
  editor =	{Timpf, Sabine and Schlieder, Christoph and Kattenbeck, Markus and Ludwig, Bernd and Stewart, Kathleen},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.COSIT.2019.6},
  URN =		{urn:nbn:de:0030-drops-110984},
  doi =		{10.4230/LIPIcs.COSIT.2019.6},
  annote =	{Keywords: spatio-temporal databases, region interpolation problem, moving regions, morphing techniques}
}
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