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584 results on '"Gamper, Johann"'

1. An Empirical Comparison of Generative Approaches for Product Attribute-Value Identification

Author

Sabeh, Kassem, Litschko, Robert, Kacimi, Mouna, Plank, Barbara, and Gamper, Johann

Subjects
Computer Science - Computation and Language, Computer Science - Artificial Intelligence
Abstract

Product attributes are crucial for e-commerce platforms, supporting applications like search, recommendation, and question answering. The task of Product Attribute and Value Identification (PAVI) involves identifying both attributes and their values from product information. In this paper, we formulate PAVI as a generation task and provide, to the best of our knowledge, the most comprehensive evaluation of PAVI so far. We compare three different attribute-value generation (AVG) strategies based on fine-tuning encoder-decoder models on three datasets. Experiments show that end-to-end AVG approach, which is computationally efficient, outperforms other strategies. However, there are differences depending on model sizes and the underlying language model. The code to reproduce all experiments is available at: https://github.com/kassemsabeh/pavi-avg

Published
2024

3. QPAVE: A Multi-task Question Answering Approach for Fine-Grained Product Attribute Value Extraction

Author

Sabeh, Kassem, Kacimi, Mouna, Gamper, Johann, Goos, Gerhard, Series 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, Wrembel, Robert, editor, Chiusano, Silvia, editor, Kotsis, Gabriele, editor, Tjoa, A Min, editor, and Khalil, Ismail, editor

Published
2024
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4. Comparison of Measures for Characterizing the Difficulty of Time Series Classification

Author

Charane, Adam, Ceccarello, Matteo, Gamper, Johann, Goos, Gerhard, Series 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, Wrembel, Robert, editor, Chiusano, Silvia, editor, Kotsis, Gabriele, editor, Tjoa, A Min, editor, and Khalil, Ismail, editor

Published
2024
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5. Indexing Temporal Relations for Range-Duration Queries

Author

Ceccarello, Matteo, Dignös, Anton, Gamper, Johann, and Khnaisser, Christina

Subjects
Computer Science - Databases
Abstract

Temporal information plays a crucial role in many database applications, however support for queries on such data is limited. We present an index structure, termed RD-index, to support range-duration queries over interval timestamped relations, which constrain both the range of the tuples' positions on the timeline and their duration. RD-index is a grid structure in the two-dimensional space, representing the position on the timeline and the duration of timestamps, respectively. Instead of using a regular grid, we consider the data distribution for the construction of the grid in order to ensure that each grid cell contains approximately the same number of intervals. RD-index features provable bounds on the running time of all the operations, allow for a simple implementation, and supports very predictable query performance. We benchmark our solution on a variety of datasets and query workloads, investigating both the query rate and the behavior of the individual queries. The results show that RD-index performs better than the baselines on range-duration queries, for which it is explicitly designed. Furthermore, it outperforms specialized indexes also on workloads containing queries constraining either only the duration or the range.

Published
2022

6. NoSQL Schema Extraction from Temporal Conceptual Model: A Case for Cassandra

Author

Mozaffari, Maryam, Dignös, Anton, Hamrouni, Hind, Gamper, Johann, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Abelló, Alberto, editor, Vassiliadis, Panos, editor, Romero, Oscar, editor, Wrembel, Robert, editor, Bugiotti, Francesca, editor, Gamper, Johann, editor, Vargas Solar, Genoveva, editor, and Zumpano, Ester, editor

Published
2023
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8. Upper Bounding the Graph Edit Distance Based on Rings and Machine Learning

Author

Blumenthal, David B., Gamper, Johann, Bougleux, Sébastien, and Brun, Luc

Subjects
Computer Science - Data Structures and Algorithms
Abstract

The graph edit distance (GED) is a flexible distance measure which is widely used for inexact graph matching. Since its exact computation is NP-hard, heuristics are used in practice. A popular approach is to obtain upper bounds for GED via transformations to the linear sum assignment problem with error-correction (LSAPE). Typically, local structures and distances between them are employed for carrying out this transformation, but recently also machine learning techniques have been used. In this paper, we formally define a unifying framework LSAPE-GED for transformations from GED to LSAPE. We also introduce rings, a new kind of local structures designed for graphs where most information resides in the topology rather than in the node labels. Furthermore, we propose two new ring based heuristics RING and RING-ML, which instantiate LSAPE-GED using the traditional and the machine learning based approach for transforming GED to LSAPE, respectively. Extensive experiments show that using rings for upper bounding GED significantly improves the state of the art on datasets where most information resides in the graphs' topologies. This closes the gap between fast but rather inaccurate LSAPE based heuristics and more accurate but significantly slower GED algorithms based on local search.

Published
2019
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9. Snapshot Semantics for Temporal Multiset Relations (Extended Version)

Author

Dignös, Anton, Glavic, Boris, Niu, Xing, Böhlen, Michael, and Gamper, Johann

Subjects
Computer Science - Databases
Abstract

Snapshot semantics is widely used for evaluating queries over temporal data: temporal relations are seen as sequences of snapshot relations, and queries are evaluated at each snapshot. In this work, we demonstrate that current approaches for snapshot semantics over interval-timestamped multiset relations are subject to two bugs regarding snapshot aggregation and bag difference. We introduce a novel temporal data model based on K-relations that overcomes these bugs and prove it to correctly encode snapshot semantics. Furthermore, we present an efficient implementation of our model as a database middleware and demonstrate experimentally that our approach is competitive with native implementations and significantly outperforms such implementations on queries that involve aggregation., Comment: extended version of PVLDB paper

Published
2019

10. Querying Temporal Anomalies in Healthcare Information Systems and Beyond

Author

Khnaisser, Christina, Hamrouni, Hind, Blumenthal, David B., Dignös, Anton, Gamper, Johann, 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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11. What’s New in Temporal Databases?

Author

Gamper, Johann, Ceccarello, Matteo, Dignös, Anton, 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. Efficient Computation of All-Window Length Correlations

Author

Charane, Adam, Ceccarello, Matteo, Dignös, Anton, Gamper, Johann, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Ivanovic, Mirjana, editor, Kirikova, Marite, editor, and Niedrite, Laila, editor

Published
2022
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13. Finding k-Dissimilar Paths with Minimum Collective Length

Author

Chondrogiannis, Theodoros, Bouros, Panagiotis, Gamper, Johann, Leser, Ulf, and Blumenthal, David B.

Subjects
Computer Science - Data Structures and Algorithms, Computer Science - Databases
Abstract

Shortest path computation is a fundamental problem in road networks. However, in many real-world scenarios, determining solely the shortest path is not enough. In this paper, we study the problem of finding k-Dissimilar Paths with Minimum Collective Length (kDPwML), which aims at computing a set of paths from a source s to a target t such that all paths are pairwise dissimilar by at least \theta and the sum of the path lengths is minimal. We introduce an exact algorithm for the kDPwML problem, which iterates over all possible s-t paths while employing two pruning techniques to reduce the prohibitively expensive computational cost. To achieve scalability, we also define the much smaller set of the simple single-via paths, and we adapt two algorithms for kDPwML queries to iterate over this set. Our experimental analysis on real road networks shows that iterating over all paths is impractical, while iterating over the set of simple single-via paths can lead to scalable solutions with only a small trade-off in the quality of the results., Comment: Extended version of the SIGSPATIAL'18 paper under the same title

Published
2018
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19. Processing Temporal and Time Series Data: Present State and Future Challenges

Author

Gamper, Johann, Dignös, Anton, 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, Darmont, Jérôme, editor, Novikov, Boris, editor, and Wrembel, Robert, editor

Published
2020
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22. GEDLIB: A C++ Library for Graph Edit Distance Computation

Author

Blumenthal, David B., Bougleux, Sébastien, Gamper, Johann, Brun, Luc, Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Pandu Rangan, C., Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Conte, Donatello, editor, Ramel, Jean-Yves, editor, and Foggia, Pasquale, editor

Published
2019
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26. Model-Based Diagnosis with Qualitative Temporal Uncertainty

Author

Nejdl, Wolfgang and Gamper, Johann

Subjects
Computer Science - Artificial Intelligence
Abstract

In this paper we describe a framework for model-based diagnosis of dynamic systems, which extends previous work in this field by using and expressing temporal uncertainty in the form of qualitative interval relations a la Allen. Based on a logical framework extended by qualitative and quantitative temporal constraints we show how to describe behavioral models (both consistency- and abductive-based), discuss how to use abstract observations and show how abstract temporal diagnoses are computed. This yields an expressive framework, which allows the representation of complex temporal behavior allowing us to represent temporal uncertainty. Due to its abstraction capabilities computation is made independent of the number of observations and time points in a temporal setting. An example of hepatitis diagnosis is used throughout the paper., Comment: Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)

Published
2013

28. Temporal Aggregation

Author

Gamper, Johann, Böhlen, Michael H., Jensen, Christian S., Snodgrass, Richard T., Section editor, Liu, Ling, editor, and Özsu, M. Tamer, editor

Published
2018
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29. Temporal Data Management – An Overview

Author

Böhlen, Michael H., Dignös, Anton, Gamper, Johann, Jensen, Christian S., van der Aalst, Wil, Series Editor, Mylopoulos, John, Series Editor, Rosemann, Michael, Series Editor, Shaw, Michael J., Series Editor, Szyperski, Clemens, Series Editor, and Zimányi, Esteban, editor

Published
2018
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30. Ring Based Approximation of Graph Edit Distance

Author

Blumenthal, David B., Bougleux, Sébastien, Gamper, Johann, Brun, Luc, 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, Bai, Xiao, editor, Hancock, Edwin R., editor, Ho, Tin Kam, editor, Wilson, Richard C., editor, Biggio, Battista, editor, and Robles-Kelly, Antonio, editor

Published
2018
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33. New Media in the Design of a Learners' Dictionary.

Author

Gamper, Johann and Knapp, Judith

Abstract

This paper presents an interdisciplinary research project that aims at developing an electronic vocabulary acquisition system for the German and the Italian language called ELDIT (Elektronisches Lern(er)worterbuch Deutsch Italienisch). The approach for studying and practicing the vocabulary. To ensure maximum effectiveness of the learning process, modern psycholinguistic methods are supplied alongside with new media and technologies including adoptive hypermedia. The system is implemented as an adaptive hyperbook and runs on the World Wide Web. The paper is structured as follows. In the second section, the concept of learners' dictionaries is introduced. In section three, the ELDIT dictionary is described in detail. Section four provides an overview of how we intend to enlarge the basic dictionary to an adaptive vocabulary acquisition system. Section five discusses related work. (Contains 16 references.) (Author/AEF)

Published
2001

35. Sparse Prefix Sums

Author

Shekelyan, Michael, Dignös, Anton, Gamper, Johann, 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, Kirikova, Mārīte, editor, Nørvåg, Kjetil, editor, and Papadopoulos, George A., editor

Published
2017
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36. Interactive Time Series Subsequence Matching

Author

Piatov, Danila, Helmer, Sven, Gamper, Johann, 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, Kirikova, Mārīte, editor, Nørvåg, Kjetil, editor, and Papadopoulos, George A., editor

Published
2017
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37. Exact Computation of Graph Edit Distance for Uniform and Non-uniform Metric Edit Costs

Author

Blumenthal, David B., Gamper, Johann, Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Pandu Rangan, C., Editorial Board Member, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Weikum, Gerhard, Series Editor, 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, Woeginger, Gerhard, Editorial Board Member, Foggia, Pasquale, editor, Liu, Cheng-Lin, editor, and Vento, Mario, editor

Published
2017
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40. Efficient Computation of Parsimonious Temporal Aggregation

Author

Mahlknecht, Giovanni, Dignös, Anton, Gamper, Johann, 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, Tadeusz, Morzy, editor, Valduriez, Patrick, editor, and Bellatreche, Ladjel, editor

Published
2015
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41. A Robust Skip-Till-Next-Match Selection Strategy for Event Pattern Matching

Author

Cadonna, Bruno, Gamper, Johann, Böhlen, Michael H., 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, Manolopoulos, Yannis, editor, Trajcevski, Goce, editor, and Kon-Popovska, Margita, editor

Published
2014
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43. Efficient Evaluation of Ad-Hoc Range Aggregates

Author

Ammendola, Christian, Böhlen, Michael H., Gamper, Johann, 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, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Bellatreche, Ladjel, editor, and Mohania, Mukesh K., editor

Published
2013
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44. ISOGA: A System for Geographical Reachability Analysis

Author

Innerebner, Markus, Böhlen, Michael, Gamper, Johann, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Liang, Steve H. L., editor, Wang, Xin, editor, and Claramunt, Christophe, editor

Published
2013
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45. Scalable Computation of Isochrones with Network Expiration

Author

Gamper, Johann, Böhlen, Michael, Innerebner, Markus, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Ailamaki, Anastasia, editor, and Bowers, Shawn, editor

Published
2012
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47. Determining Objects within Isochrones in Spatial Network Databases

Author

Marciuska, Sarunas, Gamper, Johann, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Catania, Barbara, editor, Ivanović, Mirjana, editor, and Thalheim, Bernhard, editor

Published
2010
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48. On the Efficient Construction of Multislices from Recurrences

Author

Kasperovics, Romans, Böhlen, Michael H., Gamper, Johann, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Gertz, Michael, editor, and Ludäscher, Bertram, editor

Published
2010
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