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497 results on '"Vassiliadis, Panos"'

1. A Conceptual Model for Data Storytelling Highlights in Business Intelligence Environments

Author

Vassiliadis, Panos, Marcel, Patrick, Outa, Faten El, Peralta, Veronika, and Gkitsakis, Dimos

Subjects
Computer Science - Databases, H.2
Abstract

We introduce a conceptual model for highlights to support data analysis and storytelling in the domain of Business Intelligence, via the automated extraction, representation, and exploitation of highlights revealing key facts that are hidden in the data with which a data analyst works. The model builds on the concepts of Holistic and Elementary Highlights, along with their context, constituents and interrelationships, whose synergy can identify internal properties, patterns and key facts in a dataset being analyzed., Comment: 16 pages, 4 figures

Published
2024

2. A declarative approach to data narration

Author

Marcel, Patrick, Peralta, Veronika, Outa, Faten El, and Vassiliadis, Panos

Subjects
Computer Science - Databases
Abstract

This vision paper lays the preliminary foundations for Data Narrative Management Systems (DNMS), systems that enable the storage, sharing, and manipulation of data narratives. We motivate the need for such formal foundations and introduce a simple logical framework inspired by the relational model. The core of this framework is a Data Narrative Manipulation Language inspired by the extended relational algebra. We illustrate its use via examples and discuss the main challenges for the implementation of this vision.

Published
2023

3. Cube Interestingness: Novelty, Relevance, Peculiarity and Surprise

Author

Gkitsakis, Dimos, Kaloudis, Spyridon, Mouselli, Eirini, Peralta, Veronika, Marcel, Patrick, and Vassiliadis, Panos

Subjects
Computer Science - Databases
Abstract

In this paper, we discuss methods to assess the interestingness of a query in an environment of data cubes. We assume a hierarchical multidimensional database, storing data cubes and level hierarchies. We start with a comprehensive review of related work in the fields of studies of human behavior and computer science. We define the interestingness of a query as a vector of scores along difference dimensions, like novelty, relevance, surprise and peculiarity and complement this definition with a taxonomy of the information that can be used to assess each of these dimensions of interestingness. We provide both syntactic (result-independent) checks and extensional (result-dependent) measures and algorithms for assessing the different dimensions of interestingness in a quantitative fashion. We also report our findings on a user study that we conducted, analyzing the significance of each dimension, its evolution over time and the behavior of the study's participants., Comment: 86 pages, 21 figures

Published
2022

4. A Cube Algebra with Comparative Operations: Containment, Overlap, Distance and Usability

Author

Vassiliadis, Panos

Subjects
Computer Science - Databases, H.2.1, H.2
Abstract

In this paper, we provide a comprehensive rigorous modeling for multidimensional spaces with hierarchically structured dimensions in several layers of abstractions and data cubes that live in such spaces. We model cube queries and their semantics and define typical OLAP operators like Selections, Roll-Up, Drill-Down, etc. The model serves as the basis to offer the main contribution of this paper which includes theorems and algorithms for being able to associate data cube queries via comparative operations that are evaluated only on the syntax of the queries involved. Specifically, these operations include: (a) foundational containment, referring to the coverage of common parts of the most detailed level of aggregation of the multidimensional space, (b/c) same-level containment and intersection, referring to the inclusion/existence of common parts of the multidimensional space in two query results of the same aggregation levels, (d) query distance, referring to being able to assess the similarity of two queries in the same multidimensional space, and, (e) cube usability, i.e., the possibility of computing a new cube from a previous one, defined at a different level of abstraction.

Published
2022

7. A Safari for Deviating GoF Pattern Definitions and Examples on the Web

Author

Zarras, Apostolos V., Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Almeida, João Paulo A., editor, Borbinha, José, editor, Guizzardi, Giancarlo, editor, Link, Sebastian, editor, and Zdravkovic, Jelena, editor

Published
2023
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9. Beyond Roll-Up's and Drill-Down's: An Intentional Analytics Model to Reinvent OLAP (long-version)

Author

Vassiliadis, Panos, Marcel, Patrick, and Rizzi, Stefano

Subjects
Computer Science - Databases
Abstract

This paper structures a novel vision for OLAP by fundamentally redefining several of the pillars on which OLAP has been based for the last 20 years. We redefine OLAP queries, in order to move to higher degrees of abstraction from roll-up's and drill-down's, and we propose a set of novel intentional OLAP operators, namely, describe, assess, explain, predict, and suggest, which express the user's need for results. We fundamentally redefine what a query answer is, and escape from the constraint that the answer is a set of tuples; on the contrary, we complement the set of tuples with models (typically, but not exclusively, results of data mining algorithms over the involved data) that concisely represent the internal structure or correlations of the data. Due to the diverse nature of the involved models, we come up (for the first time ever, to the best of our knowledge) with a unifying framework for them, that places its pillars on the extension of each data cell of a cube with information about the models that pertain to it -- practically converting the small parts that build up the models to data that annotate each cell. We exploit this data-to-model mapping to provide highlights of the data, by isolating data and models that maximize the delivery of new information to the user. We introduce a novel method for assessing the surprise that a new query result brings to the user, with respect to the information contained in previous results the user has seen via a new interestingness measure. The individual parts of our proposal are integrated in a new data model for OLAP, which we call the Intentional Analytics Model. We complement our contribution with a list of significant open problems for the community to address., Comment: Long v. of a paper submitted to Information Systems. Includes the formal specification of the Intentional Analytics Model at the Appendix

Published
2018
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10. Data Narrative Crafting via a Comprehensive and Well-Founded Process

Author

El Outa, Faten, Marcel, Patrick, Peralta, Veronika, da Silva, Raphaël, Chagnoux, Marie, Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Chiusano, Silvia, editor, Cerquitelli, Tania, editor, and Wrembel, Robert, editor

Published
2022
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12. An Integration-Oriented Ontology to Govern Evolution in Big Data Ecosystems

Author

Nadal, Sergi, Romero, Oscar, Abelló, Alberto, Vassiliadis, Panos, and Vansummeren, Stijn

Subjects
Computer Science - Databases
Abstract

Big Data architectures allow to flexibly store and process heterogeneous data, from multiple sources, in their original format. The structure of those data, commonly supplied by means of REST APIs, is continuously evolving. Thus data analysts need to adapt their analytical processes after each API release. This gets more challenging when performing an integrated or historical analysis. To cope with such complexity, in this paper, we present the Big Data Integration ontology, the core construct to govern the data integration process under schema evolution by systematically annotating it with information regarding the schema of the sources. We present a query rewriting algorithm that, using the annotated ontology, converts queries posed over the ontology to queries over the sources. To cope with syntactic evolution in the sources, we present an algorithm that semi-automatically adapts the ontology upon new releases. This guarantees ontology-mediated queries to correctly retrieve data from the most recent schema version as well as correctness in historical queries. A functional and performance evaluation on real-world APIs is performed to validate our approach., Comment: Preprint submitted to Information Systems. 35 pages

Published
2018
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15. A Study on the Effect of a Table’s Involvement in Foreign Keys to its Schema Evolution

Author

Dimolikas, Konstantinos, Zarras, Apostolos V., Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Dobbie, Gillian, editor, Frank, Ulrich, editor, Kappel, Gerti, editor, Liddle, Stephen W., editor, and Mayr, Heinrich C., editor

Published
2020
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16. Towards a Conceptual Model for Data Narratives

Author

El Outa, Faten, Francia, Matteo, Marcel, Patrick, Peralta, Veronika, Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Dobbie, Gillian, editor, Frank, Ulrich, editor, Kappel, Gerti, editor, Liddle, Stephen W., editor, and Mayr, Heinrich C., editor

Published
2020
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17. Do People Use Naming Conventions in SQL Programming?

Author

Papamichail, Aggelos, Zarras, Apostolos V., Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Chatzigeorgiou, Alexander, editor, Dondi, Riccardo, editor, Herodotou, Herodotos, editor, Kapoutsis, Christos, editor, Manolopoulos, Yannis, editor, Papadopoulos, George A., editor, and Sikora, Florian, editor

Published
2020
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18. Recommending Trips in the Archipelago of Refactorings

Author

Vartziotis, Theofanis, Zarras, Apostolos V., Tsimakis, Anastasios, Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Chatzigeorgiou, Alexander, editor, Dondi, Riccardo, editor, Herodotou, Herodotos, editor, Kapoutsis, Christos, editor, Manolopoulos, Yannis, editor, Papadopoulos, George A., editor, and Sikora, Florian, editor

Published
2020
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20. A Framework for Learning Cell Interestingness from Cube Explorations

Author

Marcel, Patrick, Peralta, Veronika, Vassiliadis, Panos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Welzer, Tatjana, editor, Eder, Johann, editor, Podgorelec, Vili, editor, and Kamišalić Latifić, Aida, editor

Published
2019
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25. RawVis: Visual Exploration over Raw Data

Author

Bikakis, Nikos, Maroulis, Stavros, Papastefanatos, George, Vassiliadis, Panos, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Benczúr, András, editor, Thalheim, Bernhard, editor, and Horváth, Tomáš, editor

Published
2018
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31. Schema Evolution and Foreign Keys: Birth, Eviction, Change and Absence

Author

Vassiliadis, Panos, Kolozoff, Michail-Romanos, Zerva, Maria, Zarras, Apostolos V., Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Mayr, Heinrich C., editor, Guizzardi, Giancarlo, editor, Ma, Hui, editor, and Pastor, Oscar, editor

Published
2017
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32. Schema Evolution and Gravitation to Rigidity: A Tale of Calmness in the Lives of Structured Data

Author

Vassiliadis, Panos, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Ouhammou, Yassine, editor, Ivanovic, Mirjana, editor, Abelló, Alberto, editor, and Bellatreche, Ladjel, editor

Published
2017
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33. Survival in Schema Evolution: Putting the Lives of Survivor and Dead Tables in Counterpoint

Author

Vassiliadis, Panos, Zarras, Apostolos V., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Dubois, Eric, editor, and Pohl, Klaus, editor

Published
2017
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34. Extraction of Embedded Queries via Static Analysis of Host Code

Author

Manousis, Petros, Zarras, Apostolos, Vassiliadis, Panos, Papastefanatos, George, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Dubois, Eric, editor, and Pohl, Klaus, editor

Published
2017
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36. Schema Evolution for Databases and Data Warehouses

Author

Manousis, Petros, Vassiliadis, Panos, Zarras, Apostolos, Papastefanatos, George, van der Aalst, Wil, Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Zimányi, Esteban, editor, and Abelló, Alberto, editor

Published
2016
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37. Keep Calm and Wait for the Spike! Insights on the Evolution of Amazon Services

Author

Zarras, Apostolos V., Vassiliadis, Panos, Dinos, Ioannis, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Nurcan, Selmin, editor, Soffer, Pnina, editor, Bajec, Marko, editor, and Eder, Johann, editor

Published
2016
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40. How is Life for a Table in an Evolving Relational Schema? Birth, Death and Everything in Between

Author

Vassiliadis, Panos, Zarras, Apostolos V., Skoulis, Ioannis, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Johannesson, Paul, editor, Lee, Mong Li, editor, Liddle, Stephen W., editor, Opdahl, Andreas L., editor, and Pastor López, Óscar, editor

Published
2015
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42. Visual Maps for Data-Intensive Ecosystems

Author

Kontogiannopoulou, Efthymia, Manousis, Petros, Vassiliadis, Panos, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Kobsa, Alfred, Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Yu, Eric, editor, Dobbie, Gillian, editor, Jarke, Matthias, editor, and Purao, Sandeep, editor

Published
2014
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43. Open-Source Databases: Within, Outside, or Beyond Lehman’s Laws of Software Evolution?

Author

Skoulis, Ioannis, Vassiliadis, Panos, Zarras, Apostolos, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Kobsa, Alfred, editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Weikum, Gerhard, editor, Jarke, Matthias, editor, Mylopoulos, John, editor, Quix, Christoph, editor, Rolland, Colette, editor, Manolopoulos, Yannis, editor, Mouratidis, Haralambos, editor, and Horkoff, Jennifer, editor

Published
2014
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