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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dreidimensionale Analyse der Oberkiefermorphologie bei doppelseitiger Lippen-Kiefer-Gaumenspalte in der Milchgebissphase - Vergleich zwischen frühem und spätem Gaumenspaltverschluss

Wulff, Caroline 06 December 2011 (has links) (PDF)
Complete bilateral cleft lip and palate are one of the most severe forms of orofacial deformities. This is why their rehabilitation represents a special challenge to the interdisciplinary treatment team. The ideal procedure of treatment is still today an object of controversial discussions and the aim of many investigations. Especially the right moment for the repair of the hard palate is disputed. Thereby an undisturbed development of speech contrasts to an inhibition of growth because of resulting scar tissue. To evaluate the advantages and disadvantages of several treatment concepts the analysis of plaster models has been proved to be a suitable method. In this study the maxillary morphology of cleft patients with deciduous dentition was analysed following the investigations of KRAUSE (2005) that are concerning the infant situation. Thereby it was focused on the vertical development to which item only a few studies exist until now. The patients were treated following two different concepts with early or late closure of the palate respectively, which were compared. Additionally a comparison to a group of non cleft children was made. The group of investigation derived from the archive of the “Zentrum für Mund-, Kiefer-, Gesichtschirurgie” of the University of Leipzig including models of 16 patients at the average age of 4 years and 2 months of it. The therapy of all patients was done according to the same concept which included a similar closure of the lip at an average age of 5 months after an early orthodontic treatment according to HOTZ. The closure of the palate took place at the age of 10 up to 14 which was long before the time of investigation. They were compared to a reference group of 21 cleft patients of the former “Wolfgang-Rosenthal-Klinik” in Thallwitz. The average age in this group was 4 years and 8 months. These patients underwent the same procedure as well without an orthodontic treatment and with a two-phase lip closure at the age between 4 and 6 months. The repair of the palate was made only after our point of investigation. The control group of non cleft children finally originated in a collection of the former head of the orthodontic and prosthetic compartment of the University of Leipzig Prof. Dr. Kleeberg including models of 34 patients. Also these subjects had a complete deciduous dentition. However, the exact age could not be determined. All plaster casts were measured three-dimensionally with the reflex-microscope. As reference points served special points of the mucosal surface defined by ASHLEY-MONTAGU and SILLMAN as well as by MAZAHERI. To enable vertical measurements a plane of reference was constructed with the help of the tuberosity points and the half intercanine distance. The results showed clear differences between the two cleft groups as well as to the non cleft control group. Thereby it had to be discriminated between the results of the orthodontic treatment and the lip closure and those caused by the early or late repair of the palate respectively. Considering the vertical development especially the latter became obvious. So the segmental ends of the reference group showed a more pronounced cranial collapse than those of the group of investigation what is probably due to the late closure of the palate. However the premaxilla of the group of investigation was obviously more caudal situated so the incisal point showed a significant difference to the non cleft controls. On the contrary there were greater differences within the reference group regarding the vertical position of the premaxilla which was also more rotated than in the group of investigation. Probably because of the two-phase lip closure the right end of the premaxilla was more cranial located so the vertical distance between the alveolar segment and the premaxilla was greater on the left side. Furthermore the incisal point showed a greater deviation from the midline than it was in the group of investigation what is probably also due to the two-phase lip closure. The smallest deviation from the midline was found in the control group. In transversal direction there was a similar unfavorable relation between anterior and posterior arch width in both cleft groups, what became obvious with a significant smaller segmental angle than it was in the non cleft group. This was caused by a significant smaller anterior arch width in the group of investigation whereas the posterior arch width was almost normal. This was probably due to the early orthodontic treatment and the simultaneous lip closure as well as to the early palatal closure. In contrast the anterior arch width of the reference group showed hardly any differences but the posterior width was significant greater than in the control group. This development may have been caused by the late palatal repair allowing an unimpeded growth to take place. Finally the evaluation of the sagittal relations revealed a greater arch length in the cleft groups than in the control group. The greatest distance became again obvious in the reference group. For this difference was already measured in infancy one can presume that the closure of palate did not have a great influence on that development but the orthodontic treatment did. In summary it can be concluded that the time of palatal closure is mainly relevant concerning the vertical development but also in regard of the intertuberosity width. Thus the results of this study suggest a more favorable effect of an early closure of the palate. To verify these results further studies especially after palatal closure in the reference group are necessary. Furthermore a vertical measurement related to the cranium would be suitable.
2

Dreidimensionale Analyse der Oberkiefermorphologie bei doppelseitiger Lippen-Kiefer-Gaumenspalte in der Milchgebissphase - Vergleich zwischen frühem und spätem Gaumenspaltverschluss

Wulff, Caroline 12 October 2011 (has links)
Complete bilateral cleft lip and palate are one of the most severe forms of orofacial deformities. This is why their rehabilitation represents a special challenge to the interdisciplinary treatment team. The ideal procedure of treatment is still today an object of controversial discussions and the aim of many investigations. Especially the right moment for the repair of the hard palate is disputed. Thereby an undisturbed development of speech contrasts to an inhibition of growth because of resulting scar tissue. To evaluate the advantages and disadvantages of several treatment concepts the analysis of plaster models has been proved to be a suitable method. In this study the maxillary morphology of cleft patients with deciduous dentition was analysed following the investigations of KRAUSE (2005) that are concerning the infant situation. Thereby it was focused on the vertical development to which item only a few studies exist until now. The patients were treated following two different concepts with early or late closure of the palate respectively, which were compared. Additionally a comparison to a group of non cleft children was made. The group of investigation derived from the archive of the “Zentrum für Mund-, Kiefer-, Gesichtschirurgie” of the University of Leipzig including models of 16 patients at the average age of 4 years and 2 months of it. The therapy of all patients was done according to the same concept which included a similar closure of the lip at an average age of 5 months after an early orthodontic treatment according to HOTZ. The closure of the palate took place at the age of 10 up to 14 which was long before the time of investigation. They were compared to a reference group of 21 cleft patients of the former “Wolfgang-Rosenthal-Klinik” in Thallwitz. The average age in this group was 4 years and 8 months. These patients underwent the same procedure as well without an orthodontic treatment and with a two-phase lip closure at the age between 4 and 6 months. The repair of the palate was made only after our point of investigation. The control group of non cleft children finally originated in a collection of the former head of the orthodontic and prosthetic compartment of the University of Leipzig Prof. Dr. Kleeberg including models of 34 patients. Also these subjects had a complete deciduous dentition. However, the exact age could not be determined. All plaster casts were measured three-dimensionally with the reflex-microscope. As reference points served special points of the mucosal surface defined by ASHLEY-MONTAGU and SILLMAN as well as by MAZAHERI. To enable vertical measurements a plane of reference was constructed with the help of the tuberosity points and the half intercanine distance. The results showed clear differences between the two cleft groups as well as to the non cleft control group. Thereby it had to be discriminated between the results of the orthodontic treatment and the lip closure and those caused by the early or late repair of the palate respectively. Considering the vertical development especially the latter became obvious. So the segmental ends of the reference group showed a more pronounced cranial collapse than those of the group of investigation what is probably due to the late closure of the palate. However the premaxilla of the group of investigation was obviously more caudal situated so the incisal point showed a significant difference to the non cleft controls. On the contrary there were greater differences within the reference group regarding the vertical position of the premaxilla which was also more rotated than in the group of investigation. Probably because of the two-phase lip closure the right end of the premaxilla was more cranial located so the vertical distance between the alveolar segment and the premaxilla was greater on the left side. Furthermore the incisal point showed a greater deviation from the midline than it was in the group of investigation what is probably also due to the two-phase lip closure. The smallest deviation from the midline was found in the control group. In transversal direction there was a similar unfavorable relation between anterior and posterior arch width in both cleft groups, what became obvious with a significant smaller segmental angle than it was in the non cleft group. This was caused by a significant smaller anterior arch width in the group of investigation whereas the posterior arch width was almost normal. This was probably due to the early orthodontic treatment and the simultaneous lip closure as well as to the early palatal closure. In contrast the anterior arch width of the reference group showed hardly any differences but the posterior width was significant greater than in the control group. This development may have been caused by the late palatal repair allowing an unimpeded growth to take place. Finally the evaluation of the sagittal relations revealed a greater arch length in the cleft groups than in the control group. The greatest distance became again obvious in the reference group. For this difference was already measured in infancy one can presume that the closure of palate did not have a great influence on that development but the orthodontic treatment did. In summary it can be concluded that the time of palatal closure is mainly relevant concerning the vertical development but also in regard of the intertuberosity width. Thus the results of this study suggest a more favorable effect of an early closure of the palate. To verify these results further studies especially after palatal closure in the reference group are necessary. Furthermore a vertical measurement related to the cranium would be suitable.
3

Numerical Simulations of the Gravitational Geodynamo and its Time Spectrum / Numerische Simulationen des gravitationsgetriebenen Dynamos und sein zeitliches Spektrum

Tanriverdi, Vedat 28 June 2011 (has links)
No description available.
4

Untersuchung von Feldumkehrungen an einem numerischen Modell des Geodynamos / Field reversals in a numerical model of the geodynamo

Kutzner, Carsten 27 March 2003 (has links)
No description available.
5

Evolution von ontologiebasierten Mappings in den Lebenswissenschaften / Evolution of ontology-based mappings in the life sciences

Groß, Anika 19 March 2014 (has links) (PDF)
Im Bereich der Lebenswissenschaften steht eine große und wachsende Menge heterogener Datenquellen zur Verfügung, welche häufig in quellübergreifenden Analysen und Auswertungen miteinander kombiniert werden. Um eine einheitliche und strukturierte Erfassung von Wissen sowie einen formalen Austausch zwischen verschiedenen Applikationen zu erleichtern, kommen Ontologien und andere strukturierte Vokabulare zum Einsatz. Sie finden Anwendung in verschiedenen Domänen wie der Molekularbiologie oder Chemie und dienen zumeist der Annotation realer Objekte wie z.B. Gene oder Literaturquellen. Unterschiedliche Ontologien enthalten jedoch teilweise überlappendes Wissen, so dass die Bestimmung einer Abbildung (Ontologiemapping) zwischen ihnen notwendig ist. Oft ist eine manuelle Mappingerstellung zwischen großen Ontologien kaum möglich, weshalb typischerweise automatische Verfahren zu deren Abgleich (Matching) eingesetzt werden. Aufgrund neuer Forschungserkenntnisse und Nutzeranforderungen verändern sich die Ontologien kontinuierlich weiter. Die Evolution der Ontologien hat wiederum Auswirkungen auf abhängige Daten wie beispielsweise Annotations- und Ontologiemappings, welche entsprechend aktualisiert werden müssen. Im Rahmen dieser Arbeit werden neue Methoden und Algorithmen zum Umgang mit der Evolution ontologie-basierter Mappings entwickelt. Dabei wird die generische Infrastruktur GOMMA zur Verwaltung und Analyse der Evolution von Ontologien und Mappings genutzt und erweitert. Zunächst wurde eine vergleichende Analyse der Evolution von Ontologiemappings für drei Subdomänen der Lebenswissenschaften durchgeführt. Ontologien sowie Mappings unterliegen teilweise starken Änderungen, wobei die Evolutionsintensität von der untersuchten Domäne abhängt. Insgesamt zeigt sich ein deutlicher Einfluss von Ontologieänderungen auf Ontologiemappings. Dementsprechend können bestehende Mappings infolge der Weiterentwicklung von Ontologien ungültig werden, so dass sie auf aktuelle Ontologieversionen migriert werden müssen. Dabei sollte eine aufwendige Neubestimmung der Mappings vermieden werden. In dieser Arbeit werden zwei generische Algorithmen zur (semi-) automatischen Adaptierung von Ontologiemappings eingeführt. Ein Ansatz basiert auf der Komposition von Ontologiemappings, wohingegen der andere Ansatz eine individuelle Behandlung von Ontologieänderungen zur Adaptierung der Mappings erlaubt. Beide Verfahren ermöglichen die Wiederverwendung unbeeinflusster, bereits bestätigter Mappingteile und adaptieren nur die von Änderungen betroffenen Bereiche der Mappings. Eine Evaluierung für sehr große, biomedizinische Ontologien und Mappings zeigt, dass beide Verfahren qualitativ hochwertige Ergebnisse produzieren. Ähnlich zu Ontologiemappings werden auch ontologiebasierte Annotationsmappings durch Ontologieänderungen beeinflusst. Die Arbeit stellt einen generischen Ansatz zur Bewertung der Qualität von Annotationsmappings auf Basis ihrer Evolution vor. Verschiedene Qualitätsmaße erlauben die Identifikation glaubwürdiger Annotationen beispielsweise anhand ihrer Stabilität oder Herkunftsinformationen. Eine umfassende Analyse großer Annotationsdatenquellen zeigt zahlreiche Instabilitäten z.B. aufgrund temporärer Annotationslöschungen. Dementsprechend stellt sich die Frage, inwieweit die Datenevolution zu einer Veränderung von abhängigen Analyseergebnissen führen kann. Dazu werden die Auswirkungen der Ontologie- und Annotationsevolution auf sogenannte funktionale Analysen großer biologischer Datensätze untersucht. Eine Evaluierung anhand verschiedener Stabilitätsmaße erlaubt die Bewertung der Änderungsintensität der Ergebnisse und gibt Aufschluss, inwieweit Nutzer mit einer signifikanten Veränderung ihrer Ergebnisse rechnen müssen. Darüber hinaus wird GOMMA um effiziente Verfahren für das Matching sehr großer Ontologien erweitert. Diese werden u.a. für den Abgleich neuer Konzepte während der Adaptierung von Ontologiemappings benötigt. Viele der existierenden Match-Systeme skalieren nicht für das Matching besonders großer Ontologien wie sie im Bereich der Lebenswissenschaften auftreten. Ein effizienter, kompositionsbasierter Ansatz gleicht Ontologien indirekt ab, indem existierende Mappings zu Mediatorontologien wiederverwendet und miteinander kombiniert werden. Mediatorontologien enthalten wertvolles Hintergrundwissen, so dass sich die Mappingqualität im Vergleich zu einem direkten Matching verbessern kann. Zudem werden generelle Strategien für das parallele Ontologie-Matching unter Verwendung mehrerer Rechenknoten vorgestellt. Eine größenbasierte Partitionierung der Eingabeontologien verspricht eine gute Lastbalancierung und Skalierbarkeit, da kleinere Teilaufgaben des Matchings parallel verarbeitet werden können. Die Evaluierung im Rahmen der Ontology Alignment Evaluation Initiative (OAEI) vergleicht GOMMA und andere Systeme für das Matching von Ontologien in verschiedenen Domänen. GOMMA kann u.a. durch Anwendung des parallelen und kompositionsbasierten Matchings sehr gute Ergebnisse bezüglich der Effektivität und Effizienz des Matchings, insbesondere für Ontologien aus dem Bereich der Lebenswissenschaften, erreichen. / In the life sciences, there is an increasing number of heterogeneous data sources that need to be integrated and combined in comprehensive analysis tasks. Often ontologies and other structured vocabularies are used to provide a formal representation of knowledge and to facilitate data exchange between different applications. Ontologies are used in different domains like molecular biology or chemistry. One of their most important applications is the annotation of real-world objects like genes or publications. Since different ontologies can contain overlapping knowledge it is necessary to determine mappings between them (ontology mappings). A manual mapping creation can be very time-consuming or even infeasible such that (semi-) automatic ontology matching methods are typically applied. Ontologies are not static but underlie continuous modifications due to new research insights and changing user requirements. The evolution of ontologies can have impact on dependent data like annotation or ontology mappings. This thesis presents novel methods and algorithms to deal with the evolution of ontology-based mappings. Thereby the generic infrastructure GOMMA is used and extended to manage and analyze the evolution of ontologies and mappings. First, a comparative evolution analysis for ontologies and mappings from three life science domains shows heavy changes in ontologies and mappings as well as an impact of ontology changes on the mappings. Hence, existing ontology mappings can become invalid and need to be migrated to current ontology versions. Thereby an expensive redetermination of the mappings should be avoided. This thesis introduces two generic algorithms to (semi-) automatically adapt ontology mappings: (1) a composition-based adaptation relies on the principle of mapping composition, and (2) a diff-based adaptation algorithm allows for individually handling change operations to update mappings. Both approaches reuse unaffected mapping parts, and adapt only affected parts of the mappings. An evaluation for very large biomedical ontologies and mappings shows that both approaches produce ontology mappings of high quality. Similarly, ontology changes may also affect ontology-based annotation mappings. The thesis introduces a generic evaluation approach to assess the quality of annotation mappings based on their evolution. Different quality measures allow for the identification of reliable annotations, e.g., based on their stability or provenance information. A comprehensive analysis of large annotation data sources shows numerous instabilities, e.g., due to the temporary absence of annotations. Such modifications may influence results of dependent applications such as functional enrichment analyses that describe experimental data in terms of ontological groupings. The question arises to what degree ontology and annotation changes may affect such analyses. Based on different stability measures the evaluation assesses change intensities of application results and gives insights whether users need to expect significant changes of their analysis results. Moreover, GOMMA is extended by large-scale ontology matching techniques. Such techniques are useful, a.o., to match new concepts during ontology mapping adaptation. Many existing match systems do not scale for aligning very large ontologies, e.g., from the life science domain. One efficient composition-based approach indirectly computes ontology mappings by reusing and combining existing mappings to intermediate ontologies. Intermediate ontologies can contain useful background knowledge such that the mapping quality can be improved compared to a direct match approach. Moreover, the thesis introduces general strategies for matching ontologies in parallel using several computing nodes. A size-based partitioning of the input ontologies enables good load balancing and scalability since smaller match tasks can be processed in parallel. The evaluation of the Ontology Alignment Evaluation Initiative (OAEI) compares GOMMA and other systems in terms of matching ontologies from different domains. Using the parallel and composition-based matching, GOMMA can achieve very good results w.r.t. efficiency and effectiveness, especially for ontologies from the life science domain.
6

Evolution von ontologiebasierten Mappings in den Lebenswissenschaften

Groß, Anika 05 March 2014 (has links)
Im Bereich der Lebenswissenschaften steht eine große und wachsende Menge heterogener Datenquellen zur Verfügung, welche häufig in quellübergreifenden Analysen und Auswertungen miteinander kombiniert werden. Um eine einheitliche und strukturierte Erfassung von Wissen sowie einen formalen Austausch zwischen verschiedenen Applikationen zu erleichtern, kommen Ontologien und andere strukturierte Vokabulare zum Einsatz. Sie finden Anwendung in verschiedenen Domänen wie der Molekularbiologie oder Chemie und dienen zumeist der Annotation realer Objekte wie z.B. Gene oder Literaturquellen. Unterschiedliche Ontologien enthalten jedoch teilweise überlappendes Wissen, so dass die Bestimmung einer Abbildung (Ontologiemapping) zwischen ihnen notwendig ist. Oft ist eine manuelle Mappingerstellung zwischen großen Ontologien kaum möglich, weshalb typischerweise automatische Verfahren zu deren Abgleich (Matching) eingesetzt werden. Aufgrund neuer Forschungserkenntnisse und Nutzeranforderungen verändern sich die Ontologien kontinuierlich weiter. Die Evolution der Ontologien hat wiederum Auswirkungen auf abhängige Daten wie beispielsweise Annotations- und Ontologiemappings, welche entsprechend aktualisiert werden müssen. Im Rahmen dieser Arbeit werden neue Methoden und Algorithmen zum Umgang mit der Evolution ontologie-basierter Mappings entwickelt. Dabei wird die generische Infrastruktur GOMMA zur Verwaltung und Analyse der Evolution von Ontologien und Mappings genutzt und erweitert. Zunächst wurde eine vergleichende Analyse der Evolution von Ontologiemappings für drei Subdomänen der Lebenswissenschaften durchgeführt. Ontologien sowie Mappings unterliegen teilweise starken Änderungen, wobei die Evolutionsintensität von der untersuchten Domäne abhängt. Insgesamt zeigt sich ein deutlicher Einfluss von Ontologieänderungen auf Ontologiemappings. Dementsprechend können bestehende Mappings infolge der Weiterentwicklung von Ontologien ungültig werden, so dass sie auf aktuelle Ontologieversionen migriert werden müssen. Dabei sollte eine aufwendige Neubestimmung der Mappings vermieden werden. In dieser Arbeit werden zwei generische Algorithmen zur (semi-) automatischen Adaptierung von Ontologiemappings eingeführt. Ein Ansatz basiert auf der Komposition von Ontologiemappings, wohingegen der andere Ansatz eine individuelle Behandlung von Ontologieänderungen zur Adaptierung der Mappings erlaubt. Beide Verfahren ermöglichen die Wiederverwendung unbeeinflusster, bereits bestätigter Mappingteile und adaptieren nur die von Änderungen betroffenen Bereiche der Mappings. Eine Evaluierung für sehr große, biomedizinische Ontologien und Mappings zeigt, dass beide Verfahren qualitativ hochwertige Ergebnisse produzieren. Ähnlich zu Ontologiemappings werden auch ontologiebasierte Annotationsmappings durch Ontologieänderungen beeinflusst. Die Arbeit stellt einen generischen Ansatz zur Bewertung der Qualität von Annotationsmappings auf Basis ihrer Evolution vor. Verschiedene Qualitätsmaße erlauben die Identifikation glaubwürdiger Annotationen beispielsweise anhand ihrer Stabilität oder Herkunftsinformationen. Eine umfassende Analyse großer Annotationsdatenquellen zeigt zahlreiche Instabilitäten z.B. aufgrund temporärer Annotationslöschungen. Dementsprechend stellt sich die Frage, inwieweit die Datenevolution zu einer Veränderung von abhängigen Analyseergebnissen führen kann. Dazu werden die Auswirkungen der Ontologie- und Annotationsevolution auf sogenannte funktionale Analysen großer biologischer Datensätze untersucht. Eine Evaluierung anhand verschiedener Stabilitätsmaße erlaubt die Bewertung der Änderungsintensität der Ergebnisse und gibt Aufschluss, inwieweit Nutzer mit einer signifikanten Veränderung ihrer Ergebnisse rechnen müssen. Darüber hinaus wird GOMMA um effiziente Verfahren für das Matching sehr großer Ontologien erweitert. Diese werden u.a. für den Abgleich neuer Konzepte während der Adaptierung von Ontologiemappings benötigt. Viele der existierenden Match-Systeme skalieren nicht für das Matching besonders großer Ontologien wie sie im Bereich der Lebenswissenschaften auftreten. Ein effizienter, kompositionsbasierter Ansatz gleicht Ontologien indirekt ab, indem existierende Mappings zu Mediatorontologien wiederverwendet und miteinander kombiniert werden. Mediatorontologien enthalten wertvolles Hintergrundwissen, so dass sich die Mappingqualität im Vergleich zu einem direkten Matching verbessern kann. Zudem werden generelle Strategien für das parallele Ontologie-Matching unter Verwendung mehrerer Rechenknoten vorgestellt. Eine größenbasierte Partitionierung der Eingabeontologien verspricht eine gute Lastbalancierung und Skalierbarkeit, da kleinere Teilaufgaben des Matchings parallel verarbeitet werden können. Die Evaluierung im Rahmen der Ontology Alignment Evaluation Initiative (OAEI) vergleicht GOMMA und andere Systeme für das Matching von Ontologien in verschiedenen Domänen. GOMMA kann u.a. durch Anwendung des parallelen und kompositionsbasierten Matchings sehr gute Ergebnisse bezüglich der Effektivität und Effizienz des Matchings, insbesondere für Ontologien aus dem Bereich der Lebenswissenschaften, erreichen. / In the life sciences, there is an increasing number of heterogeneous data sources that need to be integrated and combined in comprehensive analysis tasks. Often ontologies and other structured vocabularies are used to provide a formal representation of knowledge and to facilitate data exchange between different applications. Ontologies are used in different domains like molecular biology or chemistry. One of their most important applications is the annotation of real-world objects like genes or publications. Since different ontologies can contain overlapping knowledge it is necessary to determine mappings between them (ontology mappings). A manual mapping creation can be very time-consuming or even infeasible such that (semi-) automatic ontology matching methods are typically applied. Ontologies are not static but underlie continuous modifications due to new research insights and changing user requirements. The evolution of ontologies can have impact on dependent data like annotation or ontology mappings. This thesis presents novel methods and algorithms to deal with the evolution of ontology-based mappings. Thereby the generic infrastructure GOMMA is used and extended to manage and analyze the evolution of ontologies and mappings. First, a comparative evolution analysis for ontologies and mappings from three life science domains shows heavy changes in ontologies and mappings as well as an impact of ontology changes on the mappings. Hence, existing ontology mappings can become invalid and need to be migrated to current ontology versions. Thereby an expensive redetermination of the mappings should be avoided. This thesis introduces two generic algorithms to (semi-) automatically adapt ontology mappings: (1) a composition-based adaptation relies on the principle of mapping composition, and (2) a diff-based adaptation algorithm allows for individually handling change operations to update mappings. Both approaches reuse unaffected mapping parts, and adapt only affected parts of the mappings. An evaluation for very large biomedical ontologies and mappings shows that both approaches produce ontology mappings of high quality. Similarly, ontology changes may also affect ontology-based annotation mappings. The thesis introduces a generic evaluation approach to assess the quality of annotation mappings based on their evolution. Different quality measures allow for the identification of reliable annotations, e.g., based on their stability or provenance information. A comprehensive analysis of large annotation data sources shows numerous instabilities, e.g., due to the temporary absence of annotations. Such modifications may influence results of dependent applications such as functional enrichment analyses that describe experimental data in terms of ontological groupings. The question arises to what degree ontology and annotation changes may affect such analyses. Based on different stability measures the evaluation assesses change intensities of application results and gives insights whether users need to expect significant changes of their analysis results. Moreover, GOMMA is extended by large-scale ontology matching techniques. Such techniques are useful, a.o., to match new concepts during ontology mapping adaptation. Many existing match systems do not scale for aligning very large ontologies, e.g., from the life science domain. One efficient composition-based approach indirectly computes ontology mappings by reusing and combining existing mappings to intermediate ontologies. Intermediate ontologies can contain useful background knowledge such that the mapping quality can be improved compared to a direct match approach. Moreover, the thesis introduces general strategies for matching ontologies in parallel using several computing nodes. A size-based partitioning of the input ontologies enables good load balancing and scalability since smaller match tasks can be processed in parallel. The evaluation of the Ontology Alignment Evaluation Initiative (OAEI) compares GOMMA and other systems in terms of matching ontologies from different domains. Using the parallel and composition-based matching, GOMMA can achieve very good results w.r.t. efficiency and effectiveness, especially for ontologies from the life science domain.

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