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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.
851

REDUCED ORDER MODELING ENABLED PREDICTIONS OF ADDITIVE MANUFACTURING PROCESSES

Charles Reynolds Owen (19320985) 02 August 2024 (has links)
<p dir="ltr">For additive manufacturing to be a viable method to build metal parts for industries such as nuclear, the manufactured parts must be of higher quality and have lower variation in said quality than what can be achieved today. This high variation in quality bars the techniques from being used in high safety tolerance fields, such as nuclear. If this obstacle could be overcome, the benefits of additive manufacturing would be in lower cost for complex parts, as well as the ability to design and test parts in a very short timeframe, as only the CAD model needs to be created to manufacture the part. In this study, work to achieve this lower variation of quality was approached in two ways. The first was in the development of surrogate models, utilizing machine learning, to predict the end quality of additively manufactured parts. This was done by using experimental data for the mechanical properties of built parts as outputs to be predicted, and in-situ signals captured during the manufacturing process as inputs to the model. To capture the in-situ signals, cameras were used for thermal and optical imaging, leveraging the natural layer-by-layer manufacturing method used in AM techniques. The final models were created using support vector machine and gaussian process regression machine learning algorithms, giving high correlations between the insitu signals and mechanical properties of relative density, elongation to fracture, uniform elongation, and the work hardening exponent. The second approach to this study was in the development of a reduced order model for a computer simulation of an AM build. For project, a ROM was built inside the MOOSE framework, and was developed for an AM model designed by the MOOSE team, using proper orthogonal decomposition to project the problem onto a lower dimensional subspace, using POD to design the reduced basis subspace. The ROM was able to achieve a reduction to 1% the original dimensionality of the problem, while only allowing 2-5% relative error associated with the projection.</p>
852

Assessment of polycyclic aromatic hydrocarbon (PAHs) and heavy metals in the vicinity of coal power plants in South Africa

Okedeyi, Olumuyiwa Olakunle 12 November 2013 (has links)
The distribution and potential sources of 15 polycyclic aromatic hydrocarbons (PAHs) in soils and Digitaria eriantha in the vicinity of three South African coal-fired power plants, Matla, Lethabo and Rooiwal were determined by gas chromatography–mass spectrometry. An ultrasonic assisted dispersive liquid-liquid microextraction (UA-DLLME) method was developed for the extraction of polycyclic aromatic hydrocarbon in soil, followed by determination using gas chromatography mass spectrometry. The study showed that an extraction protocol based on acetonitrile as dispersive solvent and C2H2Cl2 as extracting solvent, gave extraction efficiencies comparable to conventional soxhlet extraction for soil samples. The extraction time using ultrasonication and the volume of the extraction solvent was also investigated. Using a certified reference material soil (CRM), the extraction efficiency of UA-DLLME ranged from 64 to 86% in comparison with the Soxhlet result of 73 to 95%. In comparison with the real sample, the CRM result did not show a significant difference at 95% C.I. The UA-DLLME proved to be a convenient, rapid, cost-effective and greener sample preparation approach for the determination of PAHs in soil samples. PAH compound ratios such as phenanthrene/phenanthrene + anthracene (Phen/ Phen + Anth) were used to provide a reliable estimation of emission sources. The total PAH concentration in the soils around three power plants ranged from 9.73 to 61.24 μg g−1, a range above the Agency for Toxic Substances and Disease Registry levels of 1.0 μg g−1 for a significantly contaminated site. Calculated values of the Phen/Phen + Anth ratio were 0.48±0.08, 0.44±0.05, and 0.38+0.04 for Matla, Lethabo and Rooiwal, respectively. The flouranthene/fluoranthene + pyrene (Flan/ Flan + Pyr) levels were found to be 0.49±0.03 for Matla, 0.44±0.05 for Lethabo, and 0.53±0.08 for Rooiwal. Such values indicate a xx pyrolytic source of PAHs. Higher molecular weight PAHs (five to six rings) were predominant, suggesting coal combustion sources. The carcinogenic potency B[a]P equivalent concentration (B[a] Peq) at the three power plants ranged from 3.61 to 25.25, indicating a high carcinogenic burden. The highest (B[a] Peq) was found in samples collected around Matla power station. It can, therefore, be concluded that the soils were contaminated with PAHs originating from coal-fired power stations. Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr and Zn) were analysed in soil and the Digitaria eriantha plant around three coal power plants (Matla, Lethabo and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1835.70 ± 70 μg g-1, 0.08 ± 0.05 to 1743.90 ± 29 μg g-1 and 0.07 ± 0.04 to 1735.20 ± 91 μg g-1 at Matla, Lethabo and Rooiwal respectively. The total metal concentration in the plant (Digitaria eriantha) ranged from 0.005 ± 0.003 to 534.87 ± 43 μg g-1 at Matla, 0.002 ± 0.001 to 400.49 ± 269 μg g-1 at Lethabo and 0.002 ± 0.001 to 426.91 ± 201 μg g-1 at Rooiwal. The accumulation factor (A) of less than 1 (i.e. 0.003 to 0.37) at power plants indicates a low transfer of metal from soil to plant (excluder). The enrichment factor values obtained (2.4 – 5) indicate that the soils are moderately enriched, with the exception of Pb that had significant enrichment of 20. The Geo-accumulation Index values of metals indicate that the soils are moderately polluted (0.005 – 0.65), except for Pb that showed moderate to strong pollution (1.74 – 2.53). / Chemistry / D. Phil. (Chemistry)
853

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.
854

Assessment of polycyclic aromatic hydrocarbon (PAHs) and heavy metals in the vicinity of coal power plants in South Africa

Okedeyi, Olumuyiwa Olakunle 11 1900 (has links)
The distribution and potential sources of 15 polycyclic aromatic hydrocarbons (PAHs) in soils and Digitaria eriantha in the vicinity of three South African coal-fired power plants, Matla, Lethabo and Rooiwal were determined by gas chromatography–mass spectrometry. An ultrasonic assisted dispersive liquid-liquid microextraction (UA-DLLME) method was developed for the extraction of polycyclic aromatic hydrocarbon in soil, followed by determination using gas chromatography mass spectrometry. The study showed that an extraction protocol based on acetonitrile as dispersive solvent and C2H2Cl2 as extracting solvent, gave extraction efficiencies comparable to conventional soxhlet extraction for soil samples. The extraction time using ultrasonication and the volume of the extraction solvent was also investigated. Using a certified reference material soil (CRM), the extraction efficiency of UA-DLLME ranged from 64 to 86% in comparison with the Soxhlet result of 73 to 95%. In comparison with the real sample, the CRM result did not show a significant difference at 95% C.I. The UA-DLLME proved to be a convenient, rapid, cost-effective and greener sample preparation approach for the determination of PAHs in soil samples. PAH compound ratios such as phenanthrene/phenanthrene + anthracene (Phen/ Phen + Anth) were used to provide a reliable estimation of emission sources. The total PAH concentration in the soils around three power plants ranged from 9.73 to 61.24 μg g−1, a range above the Agency for Toxic Substances and Disease Registry levels of 1.0 μg g−1 for a significantly contaminated site. Calculated values of the Phen/Phen + Anth ratio were 0.48±0.08, 0.44±0.05, and 0.38+0.04 for Matla, Lethabo and Rooiwal, respectively. The flouranthene/fluoranthene + pyrene (Flan/ Flan + Pyr) levels were found to be 0.49±0.03 for Matla, 0.44±0.05 for Lethabo, and 0.53±0.08 for Rooiwal. Such values indicate a xx pyrolytic source of PAHs. Higher molecular weight PAHs (five to six rings) were predominant, suggesting coal combustion sources. The carcinogenic potency B[a]P equivalent concentration (B[a] Peq) at the three power plants ranged from 3.61 to 25.25, indicating a high carcinogenic burden. The highest (B[a] Peq) was found in samples collected around Matla power station. It can, therefore, be concluded that the soils were contaminated with PAHs originating from coal-fired power stations. Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr and Zn) were analysed in soil and the Digitaria eriantha plant around three coal power plants (Matla, Lethabo and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1835.70 ± 70 μg g-1, 0.08 ± 0.05 to 1743.90 ± 29 μg g-1 and 0.07 ± 0.04 to 1735.20 ± 91 μg g-1 at Matla, Lethabo and Rooiwal respectively. The total metal concentration in the plant (Digitaria eriantha) ranged from 0.005 ± 0.003 to 534.87 ± 43 μg g-1 at Matla, 0.002 ± 0.001 to 400.49 ± 269 μg g-1 at Lethabo and 0.002 ± 0.001 to 426.91 ± 201 μg g-1 at Rooiwal. The accumulation factor (A) of less than 1 (i.e. 0.003 to 0.37) at power plants indicates a low transfer of metal from soil to plant (excluder). The enrichment factor values obtained (2.4 – 5) indicate that the soils are moderately enriched, with the exception of Pb that had significant enrichment of 20. The Geo-accumulation Index values of metals indicate that the soils are moderately polluted (0.005 – 0.65), except for Pb that showed moderate to strong pollution (1.74 – 2.53). / Chemistry / D. Phil. (Chemistry)
855

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.
856

Komponent pro sémantické obohacení / Semantic Enrichment Component

Doležal, Jan January 2018 (has links)
This master's thesis describes Semantic Enrichment Component (SEC), that searches entities (e.g., persons or places) in the input text document and returns information about them. The goals of this component are to create a single interface for named entity recognition tools, to enable parallel document processing, to save memory while using the knowledge base, and to speed up access to its content. To achieve these goals, the output of the named entity recognition tools in the text was specified, the tool for storing the preprocessed knowledge base into the shared memory was implemented, and the client-server scheme was used to create the component.
857

Aspects of money laundering in South African law

Van Jaarsveld, Izelde Louise 04 1900 (has links)
Money laundering involves activities which are aimed at concealing benefits that were acquired through criminal means for the purpose of making them appear legitimately acquired. Money laundering promotes criminal activities in South Africa because it allows criminals to keep the benefits that they acquired through their criminal activities. It takes place through a variety of schemes which include the use of banks. In this sense money laundering control is based on the premise that banks must be protected from providing criminals with the means to launder the benefits of their criminal activities. The Financial Intelligence Centre Act 38 of 2001 (‘FICA’) in aggregate with the Prevention of Organised Crime Act 121 of 1998 (‘POCA’) form the backbone of South Africa’s anti-money laundering regime. Like its international counterparts FICA imposes onerous duties on banks seeing that they are most often used by criminals as conduits to launder the benefits of crime. In turn, POCA criminalises activities in relation to the benefits of crime and delineates civil proceedings aimed at forfeiting the benefits of crime to the state. This study identifies the idiosyncrasies of the South African anti-money laundering regime and forwards recommendations aimed at improving its structure. To this end nine issues in relation to money laundering control and banks are investigated. The investigation fundamentally reveals that money laundering control holds unforeseen consequences for banks. In particular, a bank that receives the benefits of crimes such as fraud or theft faces prosecution if it fails to heed FICA’s money laundering control duties, for example, the filing of a suspicious transaction report. However, if the bank files a suspicious transaction report, it may be sued in civil court by the customer for breach of contract. In addition, if the bank parted with the benefits of fraud or theft whilst suspecting that the account holder may not be entitled to payment thereof, it may be sued by the victim of fraud or theft who seeks to recover loss suffered at the hand of the fraudster or thief from the bank. Ultimately, this study illustrates that amendment of some of the provisions of South Africa’s anti-money laundering legislation should enable banks to manage the aforementioned and other unforeseen consequences of money laundering control whilst at the same time contribute to the South African anti-money laundering effort. / Criminal and Procedural Law / Mercantile Law / LL.D.
858

Aspects of money laundering in South African law

Van Jaarsveld, Izelde Louise 04 1900 (has links)
Money laundering involves activities which are aimed at concealing benefits that were acquired through criminal means for the purpose of making them appear legitimately acquired. Money laundering promotes criminal activities in South Africa because it allows criminals to keep the benefits that they acquired through their criminal activities. It takes place through a variety of schemes which include the use of banks. In this sense money laundering control is based on the premise that banks must be protected from providing criminals with the means to launder the benefits of their criminal activities. The Financial Intelligence Centre Act 38 of 2001 (‘FICA’) in aggregate with the Prevention of Organised Crime Act 121 of 1998 (‘POCA’) form the backbone of South Africa’s anti-money laundering regime. Like its international counterparts FICA imposes onerous duties on banks seeing that they are most often used by criminals as conduits to launder the benefits of crime. In turn, POCA criminalises activities in relation to the benefits of crime and delineates civil proceedings aimed at forfeiting the benefits of crime to the state. This study identifies the idiosyncrasies of the South African anti-money laundering regime and forwards recommendations aimed at improving its structure. To this end nine issues in relation to money laundering control and banks are investigated. The investigation fundamentally reveals that money laundering control holds unforeseen consequences for banks. In particular, a bank that receives the benefits of crimes such as fraud or theft faces prosecution if it fails to heed FICA’s money laundering control duties, for example, the filing of a suspicious transaction report. However, if the bank files a suspicious transaction report, it may be sued in civil court by the customer for breach of contract. In addition, if the bank parted with the benefits of fraud or theft whilst suspecting that the account holder may not be entitled to payment thereof, it may be sued by the victim of fraud or theft who seeks to recover loss suffered at the hand of the fraudster or thief from the bank. Ultimately, this study illustrates that amendment of some of the provisions of South Africa’s anti-money laundering legislation should enable banks to manage the aforementioned and other unforeseen consequences of money laundering control whilst at the same time contribute to the South African anti-money laundering effort. / Criminal and Procedural Law / Mercantile Law / LL.D.
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Legal and regulatory aspects of mobile financial services

Perlman, Leon Joseph 11 1900 (has links)
The thesis deals with the emergence of bank and non-bank entities that provide a range of unique transaction-based payment services broadly called Mobile Financial Services (MFS) to unbanked, underserved and underbanked persons via mobile phones. Models of MFS from Mobile Network Operators (MNOs), banks, combinations of MNOs and banks, and independent Mobile Financial Services Providers are covered. Provision by non-banks of ‘bank-type’ services via mobile phones has been termed ‘transformational banking’ versus the ‘additive banking’ services from banks. All involve the concept of ‘branchless banking’ whereby ‘cash-in/cash out’ services are provided through ‘agents.’ Funds for MFS payments may available through a Stored Value Product (SVP), particularly through a Stored Value Account SVP variant offered by MNOs where value is stored as a redeemable fiat- or mobile ‘airtime’-based Store of Value. The competitive, legal, technical and regulatory nature of non-bank versus bank MFS models is discussed, in particular the impact of banking, payments, money laundering, telecommunications, e-commerce and consumer protection laws. Whether funding mechanisms for SVPs may amount to deposit-taking such that entities could be engaged in the ‘business of banking’ is discussed. The continued use of ‘deposit’ as the traditional trigger for the ‘business of banking’ is investigated, alongside whether transaction and paymentcentric MFS rises to the ‘business of banking.’ An extensive evaluation of ‘money’ based on the Orthodox and Claim School economic theories is undertaken in relation to SVPs used in MFS, their legal associations and import, and whether they may be deemed ‘money’ in law. Consumer protection for MFS and payments generally through current statute, contract, and payment law and common law condictiones are found to be wanting. Possible regulatory arbitrage in relation to MFS in South African law is discussed. The legal and regulatory regimes in the European Union, Kenya and the United States of America are compared with South Africa. The need for a coordinated payments-specific law that has consumer protections, enables proportional risk-based licensing of new non-bank providers of MFS, and allows for a regulator for retail payments is recommended. The use of trust companies and trust accounts is recommended for protection of user funds. | vi / Public, Constitutional and International Law / LLD
860

Legal and regulatory aspects of mobile financial services

Perlman, Leon Joseph 11 1900 (has links)
The thesis deals with the emergence of bank and non-bank entities that provide a range of unique transaction-based payment services broadly called Mobile Financial Services (MFS) to unbanked, underserved and underbanked persons via mobile phones. Models of MFS from Mobile Network Operators (MNOs), banks, combinations of MNOs and banks, and independent Mobile Financial Services Providers are covered. Provision by non-banks of ‘bank-type’ services via mobile phones has been termed ‘transformational banking’ versus the ‘additive banking’ services from banks. All involve the concept of ‘branchless banking’ whereby ‘cash-in/cash out’ services are provided through ‘agents.’ Funds for MFS payments may available through a Stored Value Product (SVP), particularly through a Stored Value Account SVP variant offered by MNOs where value is stored as a redeemable fiat- or mobile ‘airtime’-based Store of Value. The competitive, legal, technical and regulatory nature of non-bank versus bank MFS models is discussed, in particular the impact of banking, payments, money laundering, telecommunications, e-commerce and consumer protection laws. Whether funding mechanisms for SVPs may amount to deposit-taking such that entities could be engaged in the ‘business of banking’ is discussed. The continued use of ‘deposit’ as the traditional trigger for the ‘business of banking’ is investigated, alongside whether transaction and paymentcentric MFS rises to the ‘business of banking.’ An extensive evaluation of ‘money’ based on the Orthodox and Claim School economic theories is undertaken in relation to SVPs used in MFS, their legal associations and import, and whether they may be deemed ‘money’ in law. Consumer protection for MFS and payments generally through current statute, contract, and payment law and common law condictiones are found to be wanting. Possible regulatory arbitrage in relation to MFS in South African law is discussed. The legal and regulatory regimes in the European Union, Kenya and the United States of America are compared with South Africa. The need for a coordinated payments-specific law that has consumer protections, enables proportional risk-based licensing of new non-bank providers of MFS, and allows for a regulator for retail payments is recommended. The use of trust companies and trust accounts is recommended for protection of user funds. | vi / Public, Constitutional and International Law / LL. D.

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