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Documents authored by Marino, Andrea


Document
On Computing the Diameter of (Weighted) Link Streams

Authors: Marco Calamai, Pierluigi Crescenzi, and Andrea Marino

Published in: LIPIcs, Volume 190, 19th International Symposium on Experimental Algorithms (SEA 2021)


Abstract
A weighted link stream is a pair (V,𝔼) comprising V, the set of nodes, and 𝔼, the list of temporal edges (u,v,t,λ), where u,v are two nodes in V, t is the starting time of the temporal edge, and λ is its travel time. By making use of this model, different notions of diameter can be defined, which refer to the following distances: earliest arrival time, latest departure time, fastest time, and shortest time. After proving that any of these diameters cannot be computed in time sub-quadratic with respect to the number of temporal edges, we propose different algorithms (inspired by the approach used for computing the diameter of graphs) which allow us to compute, in practice very efficiently, the diameter of quite large real-world weighted link stream for several definitions of the diameter. Indeed, all the proposed algorithms require very often a very low number of single source (or target) best path computations. We verify the effectiveness of our approach by means of an extensive set of experiments on real-world link streams. We also experimentally prove that the temporal version of the well-known 2-sweep technique, for computing a lower bound on the diameter of a graph, is quite effective in the case of weighted link stream, by returning very often tight bounds.

Cite as

Marco Calamai, Pierluigi Crescenzi, and Andrea Marino. On Computing the Diameter of (Weighted) Link Streams. In 19th International Symposium on Experimental Algorithms (SEA 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 190, pp. 11:1-11:21, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)


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@InProceedings{calamai_et_al:LIPIcs.SEA.2021.11,
  author =	{Calamai, Marco and Crescenzi, Pierluigi and Marino, Andrea},
  title =	{{On Computing the Diameter of (Weighted) Link Streams}},
  booktitle =	{19th International Symposium on Experimental Algorithms (SEA 2021)},
  pages =	{11:1--11:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-185-6},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{190},
  editor =	{Coudert, David and Natale, Emanuele},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SEA.2021.11},
  URN =		{urn:nbn:de:0030-drops-137836},
  doi =		{10.4230/LIPIcs.SEA.2021.11},
  annote =	{Keywords: Temporal graph, shortest path, diameter}
}
Document
Enumeration of s-d Separators in DAGs with Application to Reliability Analysis in Temporal Graphs

Authors: Alessio Conte, Pierluigi Crescenzi, Andrea Marino, and Giulia Punzi

Published in: LIPIcs, Volume 170, 45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020)


Abstract
Temporal graphs are graphs in which arcs have temporal labels, specifying at which time they can be traversed. Motivated by recent results concerning the reliability analysis of a temporal graph through the enumeration of minimal cutsets in the corresponding line graph, in this paper we attack the problem of enumerating minimal s-d separators in s-d directed acyclic graphs (in short, s-d DAGs), also known as 2-terminal DAGs or s-t digraphs. Our main result is an algorithm for enumerating all the minimal s-d separators in a DAG with O(nm) delay, where n and m are respectively the number of nodes and arcs, and the delay is the time between the output of two consecutive solutions. To this aim, we give a characterization of the minimal s-d separators in a DAG through vertex cuts of an expanded version of the DAG itself. As a consequence of our main result, we provide an algorithm for enumerating all the minimal s-d cutsets in a temporal graph with delay O(m³), where m is the number of temporal arcs.

Cite as

Alessio Conte, Pierluigi Crescenzi, Andrea Marino, and Giulia Punzi. Enumeration of s-d Separators in DAGs with Application to Reliability Analysis in Temporal Graphs. In 45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 170, pp. 25:1-25:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{conte_et_al:LIPIcs.MFCS.2020.25,
  author =	{Conte, Alessio and Crescenzi, Pierluigi and Marino, Andrea and Punzi, Giulia},
  title =	{{Enumeration of s-d Separators in DAGs with Application to Reliability Analysis in Temporal Graphs}},
  booktitle =	{45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020)},
  pages =	{25:1--25:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-159-7},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{170},
  editor =	{Esparza, Javier and Kr\'{a}l', Daniel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2020.25},
  URN =		{urn:nbn:de:0030-drops-126932},
  doi =		{10.4230/LIPIcs.MFCS.2020.25},
  annote =	{Keywords: minimal cutset, temporal graph, minimal separator, directed acyclic graph}
}
Document
Finding Structurally and Temporally Similar Trajectories in Graphs

Authors: Roberto Grossi, Andrea Marino, and Shima Moghtasedi

Published in: LIPIcs, Volume 160, 18th International Symposium on Experimental Algorithms (SEA 2020)


Abstract
The analysis of similar motions in a network provides useful information for different applications like route recommendation. We are interested in algorithms to efficiently retrieve trajectories that are similar to a given query trajectory. For this task many studies have focused on extracting the geometrical information of trajectories. In this paper we investigate the properties of trajectories moving along the paths of a network. We provide a similarity function by making use of both the temporal aspect of trajectories and the structure of the underlying network. We propose an approximation technique that offers the top-k similar trajectories with respect to a query trajectory in an efficient way with acceptable precision. We investigate our method over real-world networks, and our experimental results show the effectiveness of the proposed method.

Cite as

Roberto Grossi, Andrea Marino, and Shima Moghtasedi. Finding Structurally and Temporally Similar Trajectories in Graphs. In 18th International Symposium on Experimental Algorithms (SEA 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 160, pp. 24:1-24:13, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{grossi_et_al:LIPIcs.SEA.2020.24,
  author =	{Grossi, Roberto and Marino, Andrea and Moghtasedi, Shima},
  title =	{{Finding Structurally and Temporally Similar Trajectories in Graphs}},
  booktitle =	{18th International Symposium on Experimental Algorithms (SEA 2020)},
  pages =	{24:1--24:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-148-1},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{160},
  editor =	{Faro, Simone and Cantone, Domenico},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SEA.2020.24},
  URN =		{urn:nbn:de:0030-drops-120989},
  doi =		{10.4230/LIPIcs.SEA.2020.24},
  annote =	{Keywords: Graph trajectory, approximated similarity, top-k similarity query}
}
Document
Listing Induced Steiner Subgraphs as a Compact Way to Discover Steiner Trees in Graphs

Authors: Alessio Conte, Roberto Grossi, Mamadou Moustapha Kanté, Andrea Marino, Takeaki Uno, and Kunihiro Wasa

Published in: LIPIcs, Volume 138, 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019)


Abstract
This paper investigates induced Steiner subgraphs as a variant of the classical Steiner trees, so as to compactly represent the (exponentially many) Steiner trees sharing the same underlying induced subgraph. We prove that the enumeration of all (inclusion-minimal) induced Steiner subgraphs is harder than the well-known Hypergraph Transversal enumeration problem if the number of terminals is not fixed. When the number of terminals is fixed, we propose a polynomial delay algorithm for listing all induced Steiner subgraphs of minimum size. We also propose a polynomial delay algorithm for listing the set of minimal induced Steiner subgraphs when the number of terminals is 3.

Cite as

Alessio Conte, Roberto Grossi, Mamadou Moustapha Kanté, Andrea Marino, Takeaki Uno, and Kunihiro Wasa. Listing Induced Steiner Subgraphs as a Compact Way to Discover Steiner Trees in Graphs. In 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 138, pp. 73:1-73:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{conte_et_al:LIPIcs.MFCS.2019.73,
  author =	{Conte, Alessio and Grossi, Roberto and Kant\'{e}, Mamadou Moustapha and Marino, Andrea and Uno, Takeaki and Wasa, Kunihiro},
  title =	{{Listing Induced Steiner Subgraphs as a Compact Way to Discover Steiner Trees in Graphs}},
  booktitle =	{44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019)},
  pages =	{73:1--73:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-117-7},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{138},
  editor =	{Rossmanith, Peter and Heggernes, Pinar and Katoen, Joost-Pieter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2019.73},
  URN =		{urn:nbn:de:0030-drops-110174},
  doi =		{10.4230/LIPIcs.MFCS.2019.73},
  annote =	{Keywords: Graph algorithms, enumeration, listing and counting, Steiner trees, induced subgraphs}
}
Document
Listing Subgraphs by Cartesian Decomposition

Authors: Alessio Conte, Roberto Grossi, Andrea Marino, Romeo Rizzi, and Luca Versari

Published in: LIPIcs, Volume 117, 43rd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018)


Abstract
We investigate a decomposition technique for listing problems in graphs and set systems. It is based on the Cartesian product of some iterators, which list the solutions of simpler problems. Our ideas applies to several problems, and we illustrate one of them in depth, namely, listing all minimum spanning trees of a weighted graph G. Here iterators over the spanning trees for unweighted graphs can be obtained by a suitable modification of the listing algorithm by [Shioura et al., SICOMP 1997], and the decomposition of G is obtained by suitably partitioning its edges according to their weights. By combining these iterators in a Cartesian product scheme that employs Gray coding, we give the first algorithm which lists all minimum spanning trees of G in constant delay, where the delay is the time elapsed between any two consecutive outputs. Our solution requires polynomial preprocessing time and uses polynomial space.

Cite as

Alessio Conte, Roberto Grossi, Andrea Marino, Romeo Rizzi, and Luca Versari. Listing Subgraphs by Cartesian Decomposition. In 43rd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 117, pp. 84:1-84:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2018)


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@InProceedings{conte_et_al:LIPIcs.MFCS.2018.84,
  author =	{Conte, Alessio and Grossi, Roberto and Marino, Andrea and Rizzi, Romeo and Versari, Luca},
  title =	{{Listing Subgraphs by Cartesian Decomposition}},
  booktitle =	{43rd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018)},
  pages =	{84:1--84:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-086-6},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{117},
  editor =	{Potapov, Igor and Spirakis, Paul and Worrell, James},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2018.84},
  URN =		{urn:nbn:de:0030-drops-96666},
  doi =		{10.4230/LIPIcs.MFCS.2018.84},
  annote =	{Keywords: Graph algorithms, listing, minimum spanning trees, constant delay}
}
Document
Sublinear-Space Bounded-Delay Enumeration for Massive Network Analytics: Maximal Cliques

Authors: Alessio Conte, Roberto Grossi, Andrea Marino, and Luca Versari

Published in: LIPIcs, Volume 55, 43rd International Colloquium on Automata, Languages, and Programming (ICALP 2016)


Abstract
Due to the sheer size of real-world networks, delay and space become quite relevant measures for the cost of enumeration in network analytics. This paper presents efficient algorithms for listing maximum cliques in networks, providing the first sublinear-space bounds with guaranteed delay per enumerated clique, thus comparing favorably with the known literature.

Cite as

Alessio Conte, Roberto Grossi, Andrea Marino, and Luca Versari. Sublinear-Space Bounded-Delay Enumeration for Massive Network Analytics: Maximal Cliques. In 43rd International Colloquium on Automata, Languages, and Programming (ICALP 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 55, pp. 148:1-148:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)


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@InProceedings{conte_et_al:LIPIcs.ICALP.2016.148,
  author =	{Conte, Alessio and Grossi, Roberto and Marino, Andrea and Versari, Luca},
  title =	{{Sublinear-Space Bounded-Delay Enumeration for Massive Network Analytics: Maximal Cliques}},
  booktitle =	{43rd International Colloquium on Automata, Languages, and Programming (ICALP 2016)},
  pages =	{148:1--148:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-013-2},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{55},
  editor =	{Chatzigiannakis, Ioannis and Mitzenmacher, Michael and Rabani, Yuval and Sangiorgi, Davide},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2016.148},
  URN =		{urn:nbn:de:0030-drops-62927},
  doi =		{10.4230/LIPIcs.ICALP.2016.148},
  annote =	{Keywords: Enumeration algorithms, maximal cliques, network mining and analytics, reverse search, space efficiency}
}
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