8 Search Results for "Henriques, Rui"

Document
DOI: 10.4230/LIPIcs.STACS.2026.26
Approximate Cartesian Tree Matching with Substitutions

Authors: Panagiotis Charalampopoulos, Jonas Ellert, and Manal Mohamed

Published in: LIPIcs, Volume 364, 43rd International Symposium on Theoretical Aspects of Computer Science (STACS 2026)

Abstract
The Cartesian tree of a sequence captures the relative order of the sequence’s elements. In recent years, Cartesian tree matching has attracted considerable attention, particularly due to its applications in time series analysis. Consider a text T of length n and a pattern P of length m. In the exact Cartesian tree matching problem, the task is to find all length-m fragments of T whose Cartesian tree coincides with the Cartesian tree CT(P) of the pattern. Although the exact version of the problem can be solved in linear time [Park et al., TCS 2020], it remains rather restrictive; for example, it is not robust to outliers in the pattern. To overcome this limitation, we consider the approximate setting, where the goal is to identify all fragments of T that are close to some string whose Cartesian tree matches CT(P). In this work, we quantify closeness via the widely used Hamming distance metric. For a given integer parameter k > 0, we present an algorithm that computes all fragments of T that are at Hamming distance at most k from a string whose Cartesian tree matches CT(P). Our algorithm runs in time 𝒪(n √m ⋅ k^{2.5}) for k ≤ m^{1/5} and in time 𝒪(nk⁵) for k ≥ m^{1/5}, thereby improving upon the state-of-the-art 𝒪(nmk)-time algorithm of Kim and Han [TCS 2025] in the regime k = o(m^{1/4}). On the way to our solution, we develop a toolbox of independent interest. First, we introduce a new notion of periodicity in Cartesian trees. Then, we lift multiple well-known combinatorial and algorithmic results for string matching and periodicity in strings to Cartesian tree matching and periodicity in Cartesian trees.
Cite as

Panagiotis Charalampopoulos, Jonas Ellert, and Manal Mohamed. Approximate Cartesian Tree Matching with Substitutions. In 43rd International Symposium on Theoretical Aspects of Computer Science (STACS 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 364, pp. 26:1-26:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

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@InProceedings{charalampopoulos_et_al:LIPIcs.STACS.2026.26,
  author =	{Charalampopoulos, Panagiotis and Ellert, Jonas and Mohamed, Manal},
  title =	{{Approximate Cartesian Tree Matching with Substitutions}},
  booktitle =	{43rd International Symposium on Theoretical Aspects of Computer Science (STACS 2026)},
  pages =	{26:1--26:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-412-3},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{364},
  editor =	{Mahajan, Meena and Manea, Florin and McIver, Annabelle and Thắng, Nguy\~{ê}n Kim},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2026.26},
  URN =		{urn:nbn:de:0030-drops-255151},
  doi =		{10.4230/LIPIcs.STACS.2026.26},
  annote =	{Keywords: Cartesian tree, Hamming distance, approximate pattern matching}
}
Document
DOI: 10.4230/OASIcs.SLATE.2021.15
NetLangEd, A Web Editor to Support Online Comment Annotation

Authors: Rui Rodrigues, Cristiana Araújo, and Pedro Rangel Henriques

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

Abstract
This paper focuses on the scientific areas of Digital Humanities, Social Networks and Inappropriate Social Discourse. The main objective of this research project is the development of an editor that allows researchers in the human and social sciences or psychologists to add their reflections or ideas out coming from reading and analyzing posts and comments of an online corpus . In the present context, the editor is being integrated with the analysis tools available in the NetLang platform. NetLangEd, in addition to allowing the three basic operations of adding, editing and removing annotations, will also offer mechanisms to manage, organize, view and locate annotations, all of which will be performed in an easy, fast and user-friendly way.
Cite as

Rui Rodrigues, Cristiana Araújo, and Pedro Rangel Henriques. NetLangEd, A Web Editor to Support Online Comment Annotation. In 10th Symposium on Languages, Applications and Technologies (SLATE 2021). Open Access Series in Informatics (OASIcs), Volume 94, pp. 15:1-15:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{rodrigues_et_al:OASIcs.SLATE.2021.15,
  author =	{Rodrigues, Rui and Ara\'{u}jo, Cristiana and Henriques, Pedro Rangel},
  title =	{{NetLangEd, A Web Editor to Support Online Comment Annotation}},
  booktitle =	{10th Symposium on Languages, Applications and Technologies (SLATE 2021)},
  pages =	{15:1--15:16},
  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.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2021.15},
  URN =		{urn:nbn:de:0030-drops-144325},
  doi =		{10.4230/OASIcs.SLATE.2021.15},
  annote =	{Keywords: Online Annotation tool, Document Markup System, Text Editor, Discourse Analysis}
}
Document
DOI: 10.4230/OASIcs.ICPEC.2021.4
Melodic - Teaching Computational Thinking to Visually Impaired Kids

Authors: Rui Costa, Cristiana Araújo, and Pedro Rangel Henriques

Published in: OASIcs, Volume 91, Second International Computer Programming Education Conference (ICPEC 2021)

Abstract
This paper presents a proposal, called Melodic, to develop Computational Thinking skills in kids with special educational needs, in this case blindness. The aim of this research is to characterize the subject and identify what are the current most used and best practises to teach this different way of Thinking to kids under those circumstances. In this paper more technical aspects are discussed, such as the architecture for the proposed application in order to accomplish the project goals. Melodic was carefully designed to have an intuitive interface for blind people and a seamless workflow, combining tactile hardware, and QR Code technology with a sound based output.
Cite as

Rui Costa, Cristiana Araújo, and Pedro Rangel Henriques. Melodic - Teaching Computational Thinking to Visually Impaired Kids. In Second International Computer Programming Education Conference (ICPEC 2021). Open Access Series in Informatics (OASIcs), Volume 91, pp. 4:1-4:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{costa_et_al:OASIcs.ICPEC.2021.4,
  author =	{Costa, Rui and Ara\'{u}jo, Cristiana and Henriques, Pedro Rangel},
  title =	{{Melodic - Teaching Computational Thinking to Visually Impaired Kids}},
  booktitle =	{Second International Computer Programming Education Conference (ICPEC 2021)},
  pages =	{4:1--4:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-194-8},
  ISSN =	{2190-6807},
  year =	{2021},
  volume =	{91},
  editor =	{Henriques, Pedro Rangel and Portela, Filipe and Queir\'{o}s, Ricardo and Sim\~{o}es, Alberto},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICPEC.2021.4},
  URN =		{urn:nbn:de:0030-drops-142205},
  doi =		{10.4230/OASIcs.ICPEC.2021.4},
  annote =	{Keywords: Computational Thinking, Visual Impaired Students Education, Teaching through Music, Learning Resource}
}
Document
DOI: 10.4230/OASIcs.ICPEC.2021.9
Moopec: A Tool for Creating Programming Problems

Authors: Rui C. Mendes

Published in: OASIcs, Volume 91, Second International Computer Programming Education Conference (ICPEC 2021)

Abstract
This paper presents a tool called Mooshak ProblEm Creator (Moopec) for facilitating the creation of programming exercises for a web-based multi-site programming contest system called Mooshak [Leal and Silva, 2003]. Users only need to create a text file for specifying all the information concerning problems including their description, tests and user feedback. This tool provides ways of automating most tasks involved in creating problems in Mooshak and, consequently, increases teachers' productivity. Moopec allows instructors to quickly create problem sets by simply editing a text file. Moopec is implemented in Python and is available at https://github.com/rcm/mooshak_problem_creator.
Cite as

Rui C. Mendes. Moopec: A Tool for Creating Programming Problems. In Second International Computer Programming Education Conference (ICPEC 2021). Open Access Series in Informatics (OASIcs), Volume 91, pp. 9:1-9:7, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{mendes:OASIcs.ICPEC.2021.9,
  author =	{Mendes, Rui C.},
  title =	{{Moopec: A Tool for Creating Programming Problems}},
  booktitle =	{Second International Computer Programming Education Conference (ICPEC 2021)},
  pages =	{9:1--9:7},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-194-8},
  ISSN =	{2190-6807},
  year =	{2021},
  volume =	{91},
  editor =	{Henriques, Pedro Rangel and Portela, Filipe and Queir\'{o}s, Ricardo and Sim\~{o}es, Alberto},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICPEC.2021.9},
  URN =		{urn:nbn:de:0030-drops-142253},
  doi =		{10.4230/OASIcs.ICPEC.2021.9},
  annote =	{Keywords: Automatic Program Assessment, Batch Generation, Testing}
}
Document
Short Paper
DOI: 10.4230/OASIcs.ICPEC.2021.13
A Teaching Assistant for the C Language (Short Paper)

Authors: Rui C. Mendes and José João Almeida

Published in: OASIcs, Volume 91, Second International Computer Programming Education Conference (ICPEC 2021)

Abstract
We introduce a C tutor that can help instructors manage classes with many students learning to program in C. Nowadays, it is easy to evaluate code but it is hard to provide good feedback. We introduce a tool to help instructors provide students with feedback concerning their implementation and documentation for honing their programming skills. This tool is implemented in Python and is available at https://github.com/rcm/C_teaching_assistant.
Cite as

Rui C. Mendes and José João Almeida. A Teaching Assistant for the C Language (Short Paper). In Second International Computer Programming Education Conference (ICPEC 2021). Open Access Series in Informatics (OASIcs), Volume 91, pp. 13:1-13:8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{mendes_et_al:OASIcs.ICPEC.2021.13,
  author =	{Mendes, Rui C. and Almeida, Jos\'{e} Jo\~{a}o},
  title =	{{A Teaching Assistant for the C Language}},
  booktitle =	{Second International Computer Programming Education Conference (ICPEC 2021)},
  pages =	{13:1--13:8},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-194-8},
  ISSN =	{2190-6807},
  year =	{2021},
  volume =	{91},
  editor =	{Henriques, Pedro Rangel and Portela, Filipe and Queir\'{o}s, Ricardo and Sim\~{o}es, Alberto},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICPEC.2021.13},
  URN =		{urn:nbn:de:0030-drops-142296},
  doi =		{10.4230/OASIcs.ICPEC.2021.13},
  annote =	{Keywords: Software metrics, Documentation extractor, Domain specific language, Query language, Report generation}
}
Document
DOI: 10.4230/OASIcs.SLATE.2018.5
eOS: The Exercise Operating System

Authors: Rui Mendes and José João Almeida

Published in: OASIcs, Volume 62, 7th Symposium on Languages, Applications and Technologies (SLATE 2018)

Abstract
We present an architecture for a system for creating, adapting and evaluating programming exercises for students. The system is capable of generating exercise skeletons, automatically creating inputs and outputs, provide a way of creating a large number of exercises programmatically and allowing students to solve them while giving them feedback. Furthermore, it allows the creation of special comparators that can check whether the output of a given submission is equivalent to the expected one or simply check whether the above mentioned output corresponds to a correct solution.
Cite as

Rui Mendes and José João Almeida. eOS: The Exercise Operating System. In 7th Symposium on Languages, Applications and Technologies (SLATE 2018). Open Access Series in Informatics (OASIcs), Volume 62, pp. 5:1-5:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@InProceedings{mendes_et_al:OASIcs.SLATE.2018.5,
  author =	{Mendes, Rui and Almeida, Jos\'{e} Jo\~{a}o},
  title =	{{eOS: The Exercise Operating System}},
  booktitle =	{7th Symposium on Languages, Applications and Technologies (SLATE 2018)},
  pages =	{5:1--5:13},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-072-9},
  ISSN =	{2190-6807},
  year =	{2018},
  volume =	{62},
  editor =	{Henriques, Pedro Rangel and Leal, Jos\'{e} Paulo and Leit\~{a}o, Ant\'{o}nio Menezes and Guinovart, Xavier G\'{o}mez},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2018.5},
  URN =		{urn:nbn:de:0030-drops-92630},
  doi =		{10.4230/OASIcs.SLATE.2018.5},
  annote =	{Keywords: domain specific language, code generation, automatic evaluation, testing}
}
Document
DOI: 10.4230/OASIcs.SLATE.2018.12
ASAPP 2.0: Advancing the state-of-the-art of semantic textual similarity for Portuguese

Authors: Ana Alves, Hugo Gonçalo Oliveira, Ricardo Rodrigues, and Rui Encarnação

Published in: OASIcs, Volume 62, 7th Symposium on Languages, Applications and Technologies (SLATE 2018)

Abstract
Semantic Textual Similarity (STS) aims at computing the proximity of meaning transmitted by two sentences. In 2016, the ASSIN shared task targeted STS in Portuguese and released training and test collections. This paper describes the development of ASAPP, a system that participated in ASSIN, but has been improved since then, and now achieves the best results in this task. ASAPP learns a STS function from a broad range of lexical, syntactic, semantic and distributional features. This paper describes the features used in the current version of ASAPP, and how they are exploited in a regression algorithm to achieve the best published results for ASSIN to date, in both European and Brazilian Portuguese.
Cite as

Ana Alves, Hugo Gonçalo Oliveira, Ricardo Rodrigues, and Rui Encarnação. ASAPP 2.0: Advancing the state-of-the-art of semantic textual similarity for Portuguese. In 7th Symposium on Languages, Applications and Technologies (SLATE 2018). Open Access Series in Informatics (OASIcs), Volume 62, pp. 12:1-12:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@InProceedings{alves_et_al:OASIcs.SLATE.2018.12,
  author =	{Alves, Ana and Gon\c{c}alo Oliveira, Hugo and Rodrigues, Ricardo and Encarna\c{c}\~{a}o, Rui},
  title =	{{ASAPP 2.0: Advancing the state-of-the-art of semantic textual similarity for Portuguese}},
  booktitle =	{7th Symposium on Languages, Applications and Technologies (SLATE 2018)},
  pages =	{12:1--12:17},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-072-9},
  ISSN =	{2190-6807},
  year =	{2018},
  volume =	{62},
  editor =	{Henriques, Pedro Rangel and Leal, Jos\'{e} Paulo and Leit\~{a}o, Ant\'{o}nio Menezes and Guinovart, Xavier G\'{o}mez},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.SLATE.2018.12},
  URN =		{urn:nbn:de:0030-drops-92709},
  doi =		{10.4230/OASIcs.SLATE.2018.12},
  annote =	{Keywords: natural language processing, semantic textual similarity, semantic relations, word embeddings, character n-grams, supervised machine learning}
}
Document
DOI: 10.4230/LIPIcs.CPM.2018.2
Order-Preserving Pattern Matching Indeterminate Strings

Authors: Rui Henriques, Alexandre P. Francisco, Luís M. S. Russo, and Hideo Bannai

Published in: LIPIcs, Volume 105, 29th Annual Symposium on Combinatorial Pattern Matching (CPM 2018)

Abstract
Given an indeterminate string pattern p and an indeterminate string text t, the problem of order-preserving pattern matching with character uncertainties (muOPPM) is to find all substrings of t that satisfy one of the possible orderings defined by p. When the text and pattern are determinate strings, we are in the presence of the well-studied exact order-preserving pattern matching (OPPM) problem with diverse applications on time series analysis. Despite its relevance, the exact OPPM problem suffers from two major drawbacks: 1) the inability to deal with indetermination in the text, thus preventing the analysis of noisy time series; and 2) the inability to deal with indetermination in the pattern, thus imposing the strict satisfaction of the orders among all pattern positions. In this paper, we provide the first polynomial algorithms to answer the muOPPM problem when: 1) indetermination is observed on the pattern or text; and 2) indetermination is observed on both the pattern and the text and given by uncertainties between pairs of characters. First, given two strings with the same length m and O(r) uncertain characters per string position, we show that the muOPPM problem can be solved in O(mr lg r) time when one string is indeterminate and r in N^+ and in O(m^2) time when both strings are indeterminate and r=2. Second, given an indeterminate text string of length n, we show that muOPPM can be efficiently solved in polynomial time and linear space.
Cite as

Rui Henriques, Alexandre P. Francisco, Luís M. S. Russo, and Hideo Bannai. Order-Preserving Pattern Matching Indeterminate Strings. In 29th Annual Symposium on Combinatorial Pattern Matching (CPM 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 105, pp. 2:1-2:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@InProceedings{henriques_et_al:LIPIcs.CPM.2018.2,
  author =	{Henriques, Rui and Francisco, Alexandre P. and Russo, Lu{\'\i}s M. S. and Bannai, Hideo},
  title =	{{Order-Preserving Pattern Matching Indeterminate Strings}},
  booktitle =	{29th Annual Symposium on Combinatorial Pattern Matching (CPM 2018)},
  pages =	{2:1--2:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-074-3},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{105},
  editor =	{Navarro, Gonzalo and Sankoff, David and Zhu, Binhai},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CPM.2018.2},
  URN =		{urn:nbn:de:0030-drops-87087},
  doi =		{10.4230/LIPIcs.CPM.2018.2},
  annote =	{Keywords: Order-preserving pattern matching, Indeterminate string analysis, Generic pattern matching, Satisfiability}
}
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