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19 results on '"Köpcke, Hanna"'

1. Construction of Knowledge Graphs: State and Challenges

Author

Hofer, Marvin, Obraczka, Daniel, Saeedi, Alieh, Köpcke, Hanna, and Rahm, Erhard

Subjects
Computer Science - Artificial Intelligence, Computer Science - Databases, Computer Science - Machine Learning
Abstract

With knowledge graphs (KGs) at the center of numerous applications such as recommender systems and question answering, the need for generalized pipelines to construct and continuously update such KGs is increasing. While the individual steps that are necessary to create KGs from unstructured (e.g. text) and structured data sources (e.g. databases) are mostly well-researched for their one-shot execution, their adoption for incremental KG updates and the interplay of the individual steps have hardly been investigated in a systematic manner so far. In this work, we first discuss the main graph models for KGs and introduce the major requirement for future KG construction pipelines. Next, we provide an overview of the necessary steps to build high-quality KGs, including cross-cutting topics such as metadata management, ontology development, and quality assurance. We then evaluate the state of the art of KG construction w.r.t the introduced requirements for specific popular KGs as well as some recent tools and strategies for KG construction. Finally, we identify areas in need of further research and improvement., Comment: 51 pages, 5 figures, 4 tables, 328 references

Published
2023
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2. Construction of Knowledge Graphs: Current State and Challenges.

Author

Hofer, Marvin, Obraczka, Daniel, Saeedi, Alieh, Köpcke, Hanna, and Rahm, Erhard

Subjects
KNOWLEDGE graphs, DATA integration, RECOMMENDER systems, DATA science, QUALITY assurance
Abstract

With Knowledge Graphs (KGs) at the center of numerous applications such as recommender systems and question-answering, the need for generalized pipelines to construct and continuously update such KGs is increasing. While the individual steps that are necessary to create KGs from unstructured sources (e.g., text) and structured data sources (e.g., databases) are mostly well researched for their one-shot execution, their adoption for incremental KG updates and the interplay of the individual steps have hardly been investigated in a systematic manner so far. In this work, we first discuss the main graph models for KGs and introduce the major requirements for future KG construction pipelines. Next, we provide an overview of the necessary steps to build high-quality KGs, including cross-cutting topics such as metadata management, ontology development, and quality assurance. We then evaluate the state of the art of KG construction with respect to the introduced requirements for specific popular KGs, as well as some recent tools and strategies for KG construction. Finally, we identify areas in need of further research and improvement. [ABSTRACT FROM AUTHOR]

Published
2024
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3. Data Partitioning for Parallel Entity Matching

Author

Kirsten, Toralf, Kolb, Lars, Hartung, Michael, Groß, Anika, Köpcke, Hanna, and Rahm, Erhard

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, H.3.4
Abstract

Entity matching is an important and difficult step for integrating web data. To reduce the typically high execution time for matching we investigate how we can perform entity matching in parallel on a distributed infrastructure. We propose different strategies to partition the input data and generate multiple match tasks that can be independently executed. One of our strategies supports both, blocking to reduce the search space for matching and parallel matching to improve efficiency. Special attention is given to the number and size of data partitions as they impact the overall communication overhead and memory requirements of individual match tasks. We have developed a service-based distributed infrastructure for the parallel execution of match workflows. We evaluate our approach in detail for different match strategies for matching real-world product data of different web shops. We also consider caching of in-put entities and affinity-based scheduling of match tasks., Comment: 11 pages

Published
2010

5. Features for Learning Local Patterns in Time-Stamped Data

Author

Morik, Katharina, Köpcke, Hanna, 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, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Morik, Katharina, editor, Boulicaut, Jean-François, editor, and Siebes, Arno, editor

Published
2005
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6. Analysing Customer Churn in Insurance Data – A Case Study

Author

Morik, Katharina, Köpcke, Hanna, 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, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Boulicaut, Jean-François, editor, Esposito, Floriana, editor, Giannotti, Fosca, editor, and Pedreschi, Dino, editor

Published
2004
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8. Analyse für die Zitierungshäufigkeit für die Datenbankkonferenz BTW

Author

Köpcke, Hanna and Rahm, Erhard

Subjects
ddc:004, Informatik, Datenbanksysteme
Abstract

Anhand von Zitierungszahlen wird oftmals versucht, die Bedeutung von wissenschaftlichen Publikationen, Zeitschriften oder ganzer Forschungsinstitute zu evaluieren. Ein häufig verwendeter Indikator für die Bedeutung einer Zeitschrift ist beispielsweise der »Impaktfaktor« [Amin & Mabe 2000]. Impaktfaktoren für zahlreiche wissenschaftliche Zeitschriften werden jährlich durch Thomson ISI im Journal Citation Report (JCR) veröffentlicht. Forschungsergebnisse aus dem Informatikbereich »Datenbanken« werden allerdings hauptsächlich auf Konferenzen veröffentlicht, die nicht von den JCR-Zitierungsdatenbanken erfasst werden. In einer kürzlich durchgeführten Auswertung [Rahm & Thor 2005] zeigten wir, dass Publikationen in den international führenden Datenbankkonferenzen SIGMOD und VLDB deutlich häufiger als Veröffentlichungen in den führenden Zeitschriften TODS und VLDB Journal zitiert werden. Für den deutschsprachigen Bereich fehlen solche Analysen bisher. Wir stellen deshalb in dieser Arbeit die Ergebnisse einer Zitationsanalyse für die Datenbanktagungsreihe BTW vor. Die BTW ist die bedeutendste Tagung zu Datenbanken und deren Anwendungen im deutschsprachigen Raum. Sie wird seit 1985 alle zwei Jahre durchgeführt. Die Abkürzung »BTW« stand bis 2001 für »Datenbanksysteme in Büro, Technik und Wissenschaft«; seit der 10. BTW-Tagung 2003 in Leipzig lautet die Tagungsbezeichnung »Datenbanksysteme für Business, Technologie und Web«. Wir evaluieren in unserer Analyse alle Publikationen, die im Rahmen der BTW in den Jahren 1985 bis 2003 erschienen sind. Die Analyse basiert auf einer Integration und Bereinigung von Daten der Quellen DBLP und Google Scholar. Der Beitrag ist wie folgt gegliedert: Abschnitt 2 informiert über die Datenquellen und die Durchführung der Analyse. Die Ergebnisse der Analyse werden in Abschnitt 3 präsentiert.

Published
2007

10. Training Selection for Tuning Entity Matching

Author

Köpcke, Hanna, Rahm, Erhard, Köpcke, Hanna, and Rahm, Erhard

Abstract

Entity matching is a crucial and difficult task for data integration. An effective solution strategy typically has to combine several techniques and to find suitable settings for critical configuration parameters such as similarity thresholds. Supervised (training-based) approaches promise to reduce the manual work for determining (learning) effective strategies for entity matching. However, they critically depend on training data selection which is a difficult problem that has so far mostly been addressed manually by human experts. In this paper we propose a training-based framework called STEM for entity matching and present different generic methods for automatically selecting training data to combine and configure several matching techniques. We evaluate the proposed methods for different match tasks and small- and medium-sized training sets.

Published
2008

11. Entwicklung eines Data Warehouses zur Durchführung von Zitierungsanalysen

Author

Köpcke, Hanna, Rahm, Erhard, Universität Leipzig, Schnerwitzki, Tino, Köpcke, Hanna, Rahm, Erhard, Universität Leipzig, and Schnerwitzki, Tino

Abstract

In vergangenen Publikationen wurden bereits verschiedene Zitierungsanalysen durchgeführt. Jedoch stets auf unterschiedlichen Datenquellen, was einen direkten Vergleich der jeweiligen Ergebnisse verhindert. Ziel dieser Arbeit soll es sein, eine Grundlage zur flexiblen Durchführung von Zitierungsanalysen zu schaffen. Durch die Entwicklung eines Data Warehouses sollen verschiedene Datenquellen integriert und konsolidiert werden, um eine Vielfalt von Analyseperspektiven und Berechnungsverfahren auf einem einheitlichen Datenbestand zu ermöglichen. Dabei wird insbesondere auf die Besonderheiten bei der Nutzung von Webdatenquellen, als wie verschiedene Methoden zur Datenbereinigung eingegangen.

Published
2008

18. Features for Learning Local Patterns in Time-Stamped Data.

Author

Boulicaut, Jean-François, Siebes, Arno, Morik, Katharina, and Köpcke, Hanna

Abstract

Time-stamped data occur frequently in real-world databases. The goal of analysing time-stamped data is very often to find a small group of objects (customers, machine parts,...) which is important for the business at hand. In contrast, the majority of objects obey well-known rules and is not of interest for the analysis. In terms of a classification task, the small group means that there are very few positive examples and within them, there is some sort of a structure such that the small group differs significantly from the majority. We may consider such a learning task learning a local pattern. Depending on the goal of the data analysis, different aspects of time are relevant, e.g., the particular date, the duration of a certain state, or the number of different states. From the given data, we may generate features that allow us to express the aspect of interest. Here, we investigate the aspect of state change and its representation for learning local patterns in time-stamped data. Besides a simple Boolean representation indicating a change, we use frequency features from information retrieval. We transfer Joachim's theory for text classification to our task and investigate its fit to local pattern learning. The approach has been implemented within the MiningMart system and was successfully applied to real-world insurance data. [ABSTRACT FROM AUTHOR]

Published
2005
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19. Entwicklung eines Data Warehouses zur Durchführung von Zitierungsanalysen

Author

Schnerwitzki, Tino, Köpcke, Hanna, Rahm, Erhard, and Universität Leipzig

Subjects
ddc:000, Citation analysis, Datawarehousing, Datenintegration, Webdaten,Zitierungsanalyse
Abstract

In vergangenen Publikationen wurden bereits verschiedene Zitierungsanalysen durchgeführt. Jedoch stets auf unterschiedlichen Datenquellen, was einen direkten Vergleich der jeweiligen Ergebnisse verhindert. Ziel dieser Arbeit soll es sein, eine Grundlage zur flexiblen Durchführung von Zitierungsanalysen zu schaffen. Durch die Entwicklung eines Data Warehouses sollen verschiedene Datenquellen integriert und konsolidiert werden, um eine Vielfalt von Analyseperspektiven und Berechnungsverfahren auf einem einheitlichen Datenbestand zu ermöglichen. Dabei wird insbesondere auf die Besonderheiten bei der Nutzung von Webdatenquellen, als wie verschiedene Methoden zur Datenbereinigung eingegangen.

Published
2008

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