Search Results

Documents authored by Ugarte, Martín

Document
DOI: 10.4230/LIPIcs.ICDT.2020.15
On the Expressiveness of Languages for Complex Event Recognition

Authors: Alejandro Grez, Cristian Riveros, Martín Ugarte, and Stijn Vansummeren

Published in: LIPIcs, Volume 155, 23rd International Conference on Database Theory (ICDT 2020)

Abstract
Complex Event Recognition (CER for short) has recently gained attention as a mechanism for detecting patterns in streams of continuously arriving event data. Numerous CER systems and languages have been proposed in the literature, commonly based on combining operations from regular expressions (sequencing, iteration, and disjunction) and relational algebra (e.g., joins and filters). While these languages are naturally first-order, meaning that variables can only bind single elements, they also provide capabilities for filtering sets of events that occur inside iterative patterns; for example requiring sequences of numbers to be increasing. Unfortunately, these type of filters usually present ad-hoc syntax and under-defined semantics, precisely because variables cannot bind sets of events. As a result, CER languages that provide filtering of sequences commonly lack rigorous semantics and their expressive power is not understood. In this paper we embark on two tasks: First, to define a denotational semantics for CER that naturally allows to bind and filter sets of events; and second, to compare the expressive power of this semantics with that of CER languages that only allow for binding single events. Concretely, we introduce Set-Oriented Complex Event Logic (SO-CEL for short), a variation of the CER language introduced in [Grez et al., 2019] in which all variables bind to sets of matched events. We then compare SO-CEL with CEL, the CER language of [Grez et al., 2019] where variables bind single events. We show that they are equivalent in expressive power when restricted to unary predicates but, surprisingly, incomparable in general. Nevertheless, we show that if we restrict to sets of binary predicates, then SO-CEL is strictly more expressive than CEL. To get a better understanding of the expressive power, computational capabilities, and limitations of SO-CEL, we also investigate the relationship between SO-CEL and Complex Event Automata (CEA), a natural computational model for CER languages. We define a property on CEA called the *-property and show that, under unary predicates, SO-CEL captures precisely the subclass of CEA that satisfy this property. Finally, we identify the operations that SO-CEL is lacking to characterize CEA and introduce a natural extension of the language that captures the complete class of CEA under unary predicates.
Cite as

Alejandro Grez, Cristian Riveros, Martín Ugarte, and Stijn Vansummeren. On the Expressiveness of Languages for Complex Event Recognition. In 23rd International Conference on Database Theory (ICDT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 155, pp. 15:1-15:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{grez_et_al:LIPIcs.ICDT.2020.15,
  author =	{Grez, Alejandro and Riveros, Cristian and Ugarte, Mart{\'\i}n and Vansummeren, Stijn},
  title =	{{On the Expressiveness of Languages for Complex Event Recognition}},
  booktitle =	{23rd International Conference on Database Theory (ICDT 2020)},
  pages =	{15:1--15:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-139-9},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{155},
  editor =	{Lutz, Carsten and Jung, Jean Christoph},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2020.15},
  URN =		{urn:nbn:de:0030-drops-119390},
  doi =		{10.4230/LIPIcs.ICDT.2020.15},
  annote =	{Keywords: Query languages, Complex Event Recognition, Logics, Automata theory}
}
Document
DOI: 10.4230/LIPIcs.STACS.2020.54
Cryptocurrency Mining Games with Economic Discount and Decreasing Rewards

Authors: Marcelo Arenas, Juan Reutter, Etienne Toussaint, Martín Ugarte, Francisco Vial, and Domagoj Vrgoč

Published in: LIPIcs, Volume 154, 37th International Symposium on Theoretical Aspects of Computer Science (STACS 2020)

Abstract
In the consensus protocols used in most cryptocurrencies, participants called miners must find valid blocks of transactions and append them to a shared tree-like data structure. Ideally, the rules of the protocol should ensure that miners maximize their gains if they follow a default strategy, which consists on appending blocks only to the longest branch of the tree, called the blockchain. Our goal is to understand under which circumstances are miners encouraged to follow the default strategy. Unfortunately, most of the existing models work with simplified payoff functions, without considering the possibility that rewards decrease over time because of the game rules (like in Bitcoin), nor integrating the fact that a miner naturally prefers to be paid earlier than later (the economic concept of discount). In order to integrate these factors, we consider a more general model where issues such as economic discount and decreasing rewards can be set as parameters of an infinite stochastic game. In this model, we study the limit situation in which a miner does not receive a full reward for a block if it stops being in the blockchain. We show that if rewards are not decreasing, then miners do not have incentives to create new branches, no matter how high their computational power is. On the other hand, when working with decreasing rewards similar to those in Bitcoin, we show that miners have an incentive to create such branches. Nevertheless, this incentive only occurs when a miner controls a proportion of the computational power which is close to half of the computational power of the entire network.
Cite as

Marcelo Arenas, Juan Reutter, Etienne Toussaint, Martín Ugarte, Francisco Vial, and Domagoj Vrgoč. Cryptocurrency Mining Games with Economic Discount and Decreasing Rewards. In 37th International Symposium on Theoretical Aspects of Computer Science (STACS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 154, pp. 54:1-54:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{arenas_et_al:LIPIcs.STACS.2020.54,
  author =	{Arenas, Marcelo and Reutter, Juan and Toussaint, Etienne and Ugarte, Mart{\'\i}n and Vial, Francisco and Vrgo\v{c}, Domagoj},
  title =	{{Cryptocurrency Mining Games with Economic Discount and Decreasing Rewards}},
  booktitle =	{37th International Symposium on Theoretical Aspects of Computer Science (STACS 2020)},
  pages =	{54:1--54:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-140-5},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{154},
  editor =	{Paul, Christophe and Bl\"{a}ser, Markus},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2020.54},
  URN =		{urn:nbn:de:0030-drops-119150},
  doi =		{10.4230/LIPIcs.STACS.2020.54},
  annote =	{Keywords: cryptocurrency, game theory, cryptomining, economic discount, decreasing rewards}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2019.5
A Formal Framework for Complex Event Processing

Authors: Alejandro Grez, Cristian Riveros, and Martín Ugarte

Published in: LIPIcs, Volume 127, 22nd International Conference on Database Theory (ICDT 2019)

Abstract
Complex Event Processing (CEP) has emerged as the unifying field for technologies that require processing and correlating distributed data sources in real-time. CEP finds applications in diverse domains, which has resulted in a large number of proposals for expressing and processing complex events. However, existing CEP languages lack from a clear semantics, making them hard to understand and generalize. Moreover, there are no general techniques for evaluating CEP query languages with clear performance guarantees. In this paper we embark on the task of giving a rigorous and efficient framework to CEP. We propose a formal language for specifying complex events, called CEL, that contains the main features used in the literature and has a denotational and compositional semantics. We also formalize the so-called selection strategies, which had only been presented as by-design extensions to existing frameworks. With a well-defined semantics at hand, we discuss how to efficiently process complex events by evaluating CEL formulas with unary filters. We start by studying the syntactical properties of CEL and propose rewriting optimization techniques for simplifying the evaluation of formulas. Then, we introduce a formal computational model for CEP, called complex event automata (CEA), and study how to compile CEL formulas with unary filters into CEA. Furthermore, we provide efficient algorithms for evaluating CEA over event streams using constant time per event followed by constant-delay enumeration of the results. Finally, we gather the main results of this work to present an efficient and declarative framework for CEP.
Cite as

Alejandro Grez, Cristian Riveros, and Martín Ugarte. A Formal Framework for Complex Event Processing. In 22nd International Conference on Database Theory (ICDT 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 127, pp. 5:1-5:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

Copy BibTex To Clipboard

@InProceedings{grez_et_al:LIPIcs.ICDT.2019.5,
  author =	{Grez, Alejandro and Riveros, Cristian and Ugarte, Mart{\'\i}n},
  title =	{{A Formal Framework for Complex Event Processing}},
  booktitle =	{22nd International Conference on Database Theory (ICDT 2019)},
  pages =	{5:1--5:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-101-6},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{127},
  editor =	{Barcelo, Pablo and Calautti, Marco},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2019.5},
  URN =		{urn:nbn:de:0030-drops-103079},
  doi =		{10.4230/LIPIcs.ICDT.2019.5},
  annote =	{Keywords: Complex event processing, streaming evaluation, constant delay enumeration}
}
Document
Complete Volume
DOI: 10.4230/LIPIcs.ICDT.2015
LIPIcs, Volume 31, ICDT'15, Complete Volume

Authors: Marcelo Arenas and Martín Ugarte

Published in: LIPIcs, Volume 31, 18th International Conference on Database Theory (ICDT 2015)

Abstract
LIPIcs, Volume 31, ICDT'15, Complete Volume
Cite as

18th International Conference on Database Theory (ICDT 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 31, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

Copy BibTex To Clipboard

@Proceedings{arenas_et_al:LIPIcs.ICDT.2015,
  title =	{{LIPIcs, Volume 31, ICDT'15, Complete Volume}},
  booktitle =	{18th International Conference on Database Theory (ICDT 2015)},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-79-8},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{31},
  editor =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2015},
  URN =		{urn:nbn:de:0030-drops-50077},
  doi =		{10.4230/LIPIcs.ICDT.2015},
  annote =	{Keywords: Database Management, Normal forms, Schema and subschema, Query languages, Query processing, Relational databases, Distributed databases, Heterogeneous Databases, Online Information Services, Miscellaneous – Privacy, Office Automation: Workflow management, Performance Analysis and Design Aids: Formal}
}
Document
Front Matter
DOI: 10.4230/LIPIcs.ICDT.2015.i
Title, Table of Contents, Preface, ICDT 2015 Test of Time Award, Organization, External Reviewers, List of Authors

Authors: Marcelo Arenas and Martín Ugarte

Published in: LIPIcs, Volume 31, 18th International Conference on Database Theory (ICDT 2015)

Abstract
Title, Table of Contents, Preface, ICDT 2015 Test of Time Award, Organization, External Reviewers, List of Authors
Cite as

18th International Conference on Database Theory (ICDT 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 31, pp. i-xvi, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

Copy BibTex To Clipboard

@InProceedings{arenas_et_al:LIPIcs.ICDT.2015.i,
  author =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  title =	{{Title, Table of Contents, Preface, ICDT 2015 Test of Time Award, Organization, External Reviewers, List of Authors}},
  booktitle =	{18th International Conference on Database Theory (ICDT 2015)},
  pages =	{i--xvi},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-79-8},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{31},
  editor =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2015.i},
  URN =		{urn:nbn:de:0030-drops-50002},
  doi =		{10.4230/LIPIcs.ICDT.2015.i},
  annote =	{Keywords: Title, Table of Contents, Preface, ICDT 2015 Test of Time Award, Organization, External Reviewers, List of Authors}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2015.212
CONSTRUCT Queries in SPARQL

Authors: Egor V. Kostylev, Juan L. Reutter, and Martín Ugarte

Published in: LIPIcs, Volume 31, 18th International Conference on Database Theory (ICDT 2015)

Abstract
SPARQL has become the most popular language for querying RDF datasets, the standard data model for representing information in the Web. This query language has received a good deal of attention in the last few years: two versions of W3C standards have been issued, several SPARQL query engines have been deployed, and important theoretical foundations have been laid. However, many fundamental aspects of SPARQL queries are not yet fully understood. To this end, it is crucial to understand the correspondence between SPARQL and well-developed frameworks like relational algebra or first order logic. But one of the main obstacles on the way to such understanding is the fact that the well-studied fragments of SPARQL do not produce RDF as output. In this paper we embark on the study of SPARQL CONSTRUCT queries, that is, queries which output RDF graphs. This class of queries takes rightful place in the standards and implementations, but contrary to SELECT queries, it has not yet attracted a worth-while theoretical research. Under this framework we are able to establish a strong connection between SPARQL and well-known logical and database formalisms. In particular, the fragment which does not allow for blank nodes in output templates corresponds to first order queries, its well-designed sub-fragment corresponds to positive first order queries, and the general language can be re-stated as a data exchange setting. These correspondences allow us to conclude that the general language is not composable, but the aforementioned blank-free fragments are. Finally, we enrich SPARQL with a recursion operator and establish fundamental properties of this extension.
Cite as

Egor V. Kostylev, Juan L. Reutter, and Martín Ugarte. CONSTRUCT Queries in SPARQL. In 18th International Conference on Database Theory (ICDT 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 31, pp. 212-229, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

Copy BibTex To Clipboard

@InProceedings{kostylev_et_al:LIPIcs.ICDT.2015.212,
  author =	{Kostylev, Egor V. and Reutter, Juan L. and Ugarte, Mart{\'\i}n},
  title =	{{CONSTRUCT Queries in SPARQL}},
  booktitle =	{18th International Conference on Database Theory (ICDT 2015)},
  pages =	{212--229},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-79-8},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{31},
  editor =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2015.212},
  URN =		{urn:nbn:de:0030-drops-49866},
  doi =		{10.4230/LIPIcs.ICDT.2015.212},
  annote =	{Keywords: RDF, SPARQL, Query Languages}
}
Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail
© 2023-2024 Schloss Dagstuhl – LZI GmbH About DROPS Imprint Privacy Contact