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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.
71

Data-Intensive Biocomputing in the Cloud

Meeramohideen Mohamed, Nabeel 25 September 2013 (has links)
Next-generation sequencing (NGS) technologies have made it possible to rapidly sequence the human genome, heralding a new era of health-care innovations based on personalized genetic information. However, these NGS technologies generate data at a rate that far outstrips Moore\'s Law. As a consequence, analyzing this exponentially increasing data deluge requires enormous computational and storage resources, resources that many life science institutions do not have access to. As such, cloud computing has emerged as an obvious, but still nascent, solution. This thesis intends to investigate and design an efficient framework for running and managing large-scale data-intensive scientific applications in the cloud. Based on the learning from our parallel implementation of a genome analysis pipeline in the cloud, we aim to provide a framework for users to run such data-intensive scientific workflows using a hybrid setup of client and cloud resources. We first present SeqInCloud, our highly scalable parallel implementation of a popular genetic variant pipeline called genome analysis toolkit (GATK), on the Windows Azure HDInsight cloud platform. Together with a parallel implementation of GATK on Hadoop, we evaluate the potential of using cloud computing for large-scale DNA analysis and present a detailed study on efficiently utilizing cloud resources for running data-intensive, life-science applications. Based on our experience from running SeqInCloud on Azure, we present CloudFlow, a feature rich workflow manager for running MapReduce-based bioinformatic pipelines utilizing both client and cloud resources. CloudFlow, built on the top of an existing MapReduce-based workflow manager called Cloudgene, provides unique features that are not offered by existing MapReduce-based workflow managers, such as enabling simultaneous use of client and cloud resources, automatic data-dependency handling between client and cloud resources, and the flexibility of implementing user-defined plugins for data transformations. In-general, we believe that our work attempts to increase the adoption of cloud resources for running data-intensive scientific workloads. / Master of Science
72

Sequence capture as a tool to understand the genomic basis for adaptation in angiosperm and gymnosperm trees

Suren, Haktan 21 June 2017 (has links)
Forest trees represent a unique group of organisms combined with ecological and economic importance. Owing to their random mating system and widespread geographical distribution, they harbor abundance genetic variation both within and among populations. Despite their importance, research in forest trees has been underrepresented majorly due to their large and complex genome and scarce funding. However, recent climate change and other associated problems such as insect outbreaks, diseases and stress related damages have urged scientists to focus more on trees. Furthermore, the advent in high-throughput sequencing technologies have allowed trees to be sequenced and used as reference genome, which provided deeper understanding between genotype and environment. Whole genome sequencing is still not possible for organisms having large genomes including most tree species, and it is still not feasible economically for population genomic studies which require sequencing hundreds of samples. To get around this problem, genomic reduction is required. Sequence capture has been one of the genomic reduction techniques enabled studying the subset of the DNA of interest. In this paper, our primary goal is to outline challenges, provide guidance about the utility of sequence capture in trees, and to leverage such data in genome-wide association analyses to find the genetic variants that underlie complex, adaptive traits in spruce and pine, as well as poplar. Results of this research will facilitate bridging the genomic information gap between trees and other organisms. Moreover, it will provide better understanding how genetic variation governs phenotype in trees, which will facilitate both marker assisted selection for improved traits as well as provide guidance to determine forest management strategies for reforestation to mitigate the effects of climate change. / Ph. D.
73

Sequenciamento e análise da variabilidade genética de vírus transmitidos por ácaros do gênero Brevipalpus no Brasil / Sequencing and analysis of the genetic variability of viruses transmitted by Brevipalpus mites in Brazil

Jesus, Camila Chabí de 20 January 2016 (has links)
Acredita-se que o Brasil é o centro de diversidade de vírus transmitidos por ácaros do gênero Brevipalpus (VTB). Alguns desses VTB infectam culturas fundamentais para o agronegócio brasileiro como citros e café, além de maracujá e de várias plantas ornamentais. Na última década os genomas de dois deles, Citrus leprosis virus C (CiLV-C) e Coffee ringspot virus (CoRSV) foram sequenciados, mas ainda é escasso o conhecimento sobre a diversidade genética e processos evolutivos envolvidos na população dessas espécies. Neste contexto, o objetivo deste trabalho foi caracterizar molecularmente novas estirpes de CiLV-C e CoRSV que infectam citros e café, respectivamente. E revelar as relações filogenéticas com espécies de VTB conhecidas, assim como avaliar a variabilidade genética da população de CiLVC no Brasil. Para o estudo de CiLV-C, 47 amostras de Citrus sinensis apresentando sintomas típicos da leprose dos citros foram coletadas em diferentes regiões do Brasil no período de 2011-2015. A presença de CiLV-C foi detectada por RT-PCR em todas as amostras coletadas e, posteriormente, foi realizado o sequenciamento de quatro regiões do genoma viral (p29, p15, RI e MP) de cada isolado. As sequências obtidas foram utilizadas no estudo de filogenia e variabilidade da população de CiLV-C no Brasil. Foi demonstrado que a população de CiLV-C apresenta uma variabilidade relativamente baixa; entretanto, foi identificada a existência de duas linhagens dentro da espécie, nomeadas Cor e SJRP. Os genomas completos de CiLV-C SJRP e também do dicorhavirus tentativo CoRSV identificado em Limeira, SP, foram obtidos mediante o sequenciamento de RNA de pequeno tamanho (siRNA). Cada sequência foi validada mediante o sequenciamento de fragmentos gerados por RT-PCR ao longo do genoma. CiLV-C SJRP apresenta cerca de 85% de identidade de nucleotídeo com o membro-tipo do gênero Cilevirus e exibe evidências de recombinação com isolados da linhagem Cor, a prevalente no território brasileiro. Globalmente, o genoma de CoRSV Limeira apresenta mais de 90% de identidade de nucleotídeo com isolado CoRSV Lavras, o que indica que ambos os isolados são membros da mesma espécie tentativa de dichorhavirus. / South America is most likely the center of diversity of Brevipalpus transmitted viruses (BTV). Some of these BTV infect major crops of the Brazilian agribusiness such as citrus and coffee. Passion fruit and several other ornamental plants are affected as well. The genome of two of these viruses, Citrus leprosis virus C (CiLV-C) and Coffee ringspot virus (CoRSV) were sequenced, but the knowledge about several molecular characteristics and processes involved in the evolution of their populations are still scarce. Thus, the objective of this study was to molecularly characterize new isolates of BTV infecting citrus and coffee, reveal the phylogenetic relationships with known species of BTV, and assess the genetic variability of the population of CiLV-C in Brazil. For CiLV-C studies, 47 samples of Citrus sinensis showing typical symptoms of leprosis were collected in different Brazilian regions during 2011-2015. The presence of CiLV-C was detected by RT-PCR in all the collected samples and four regions of the viral genome (p29, p15, IR and MP) of each isample were sequenced. It has been shown that the CiLV-C population has relatively low variability; although the existence of two lineages named Cor and SJRP were identified in this work. The complete genomes of one isolate of the lineage SJRP (CiLV-C SJRP) and that of the tentative dicorhavirus CoRSV found in Limeira, SP, were obtained by small RNA (siRNA) Sequencing. Validation was performed by sequencing fragments generated by RT-PCR using specific primers throughout the genome. CiLV-C SJRP has about 85% nucleotide identity with the genome of the type-member of the Cilevirus genus and shows evidence of recombination with isolates of the lineage Cor, which are prevalent in Brazil. CoRSV isolate Limeira has more than 90% of nucleotide identity with CoRSV Lavras, indicating that both isolates are members of the same tentative species of dichorhavirus.
74

Sequenciamento e análise da variabilidade genética de vírus transmitidos por ácaros do gênero Brevipalpus no Brasil / Sequencing and analysis of the genetic variability of viruses transmitted by Brevipalpus mites in Brazil

Camila Chabí de Jesus 20 January 2016 (has links)
Acredita-se que o Brasil é o centro de diversidade de vírus transmitidos por ácaros do gênero Brevipalpus (VTB). Alguns desses VTB infectam culturas fundamentais para o agronegócio brasileiro como citros e café, além de maracujá e de várias plantas ornamentais. Na última década os genomas de dois deles, Citrus leprosis virus C (CiLV-C) e Coffee ringspot virus (CoRSV) foram sequenciados, mas ainda é escasso o conhecimento sobre a diversidade genética e processos evolutivos envolvidos na população dessas espécies. Neste contexto, o objetivo deste trabalho foi caracterizar molecularmente novas estirpes de CiLV-C e CoRSV que infectam citros e café, respectivamente. E revelar as relações filogenéticas com espécies de VTB conhecidas, assim como avaliar a variabilidade genética da população de CiLVC no Brasil. Para o estudo de CiLV-C, 47 amostras de Citrus sinensis apresentando sintomas típicos da leprose dos citros foram coletadas em diferentes regiões do Brasil no período de 2011-2015. A presença de CiLV-C foi detectada por RT-PCR em todas as amostras coletadas e, posteriormente, foi realizado o sequenciamento de quatro regiões do genoma viral (p29, p15, RI e MP) de cada isolado. As sequências obtidas foram utilizadas no estudo de filogenia e variabilidade da população de CiLV-C no Brasil. Foi demonstrado que a população de CiLV-C apresenta uma variabilidade relativamente baixa; entretanto, foi identificada a existência de duas linhagens dentro da espécie, nomeadas Cor e SJRP. Os genomas completos de CiLV-C SJRP e também do dicorhavirus tentativo CoRSV identificado em Limeira, SP, foram obtidos mediante o sequenciamento de RNA de pequeno tamanho (siRNA). Cada sequência foi validada mediante o sequenciamento de fragmentos gerados por RT-PCR ao longo do genoma. CiLV-C SJRP apresenta cerca de 85% de identidade de nucleotídeo com o membro-tipo do gênero Cilevirus e exibe evidências de recombinação com isolados da linhagem Cor, a prevalente no território brasileiro. Globalmente, o genoma de CoRSV Limeira apresenta mais de 90% de identidade de nucleotídeo com isolado CoRSV Lavras, o que indica que ambos os isolados são membros da mesma espécie tentativa de dichorhavirus. / South America is most likely the center of diversity of Brevipalpus transmitted viruses (BTV). Some of these BTV infect major crops of the Brazilian agribusiness such as citrus and coffee. Passion fruit and several other ornamental plants are affected as well. The genome of two of these viruses, Citrus leprosis virus C (CiLV-C) and Coffee ringspot virus (CoRSV) were sequenced, but the knowledge about several molecular characteristics and processes involved in the evolution of their populations are still scarce. Thus, the objective of this study was to molecularly characterize new isolates of BTV infecting citrus and coffee, reveal the phylogenetic relationships with known species of BTV, and assess the genetic variability of the population of CiLV-C in Brazil. For CiLV-C studies, 47 samples of Citrus sinensis showing typical symptoms of leprosis were collected in different Brazilian regions during 2011-2015. The presence of CiLV-C was detected by RT-PCR in all the collected samples and four regions of the viral genome (p29, p15, IR and MP) of each isample were sequenced. It has been shown that the CiLV-C population has relatively low variability; although the existence of two lineages named Cor and SJRP were identified in this work. The complete genomes of one isolate of the lineage SJRP (CiLV-C SJRP) and that of the tentative dicorhavirus CoRSV found in Limeira, SP, were obtained by small RNA (siRNA) Sequencing. Validation was performed by sequencing fragments generated by RT-PCR using specific primers throughout the genome. CiLV-C SJRP has about 85% nucleotide identity with the genome of the type-member of the Cilevirus genus and shows evidence of recombination with isolates of the lineage Cor, which are prevalent in Brazil. CoRSV isolate Limeira has more than 90% of nucleotide identity with CoRSV Lavras, indicating that both isolates are members of the same tentative species of dichorhavirus.
75

A Security Solution on Availability for Next Generation Telecommunication Networks Management Information Systems

Wu, Ming-Yi 04 September 2009 (has links)
With the development of the internet protocol (IP) and digitization for the global telecommunication industry, the convergence rate of communications and broadcasting has been improved. According to these motives, the domestic telecommunication industry modify present commercial operation managements and combine with the communication networks, the fixed-mobile communication (FMC) networks, and the mobile communication networks into the all-internet protocol (all-IP) communication network structure based on the extended upgrade communication network system. The domestic telecommunication industry expect that the integrated heterogeneous network, including the speech data, the video data, and the communication services, which can provide the omnipresent customizable mobile communication network services and obtain the advance business opportunities in terms of the future development of digital convergence. Hence, the domestic telecommunication industry not only build the next generation network structure to satisfy their demands, but also develop the management information system (MIS) to monitor the operation of telecommunication networks for ensure the quality of communication services and achieve the development of next generation networks. A primary consideration is to assure the usability of MIS for the telecommunication industry and the customers based on the profit rates and the omnipresent mobile network services, respectively¡C However, the current status of the telecommunication industry that meet the many difficult challenges and problems to construct the next generation MIS. For examples, the all-IP-based open network structure will be used instead of the close network structure, the different generation telecommunication systems combine with the operation and maintenance information system, the information security incident, and so on. It is must to consider highly of these situations between the major links above. Otherwise, the service usability of MIS will be destroyed. In this thesis, we adopt the case study approach to analyze the MIS construction process of the domestic telecommunication operator. During the build process, the MIS construction of next generation telecommunication networks must to suffice for the flexibility, the safety, and the stabilization and need to make sure the critical mission on stable operation condition, the lower service interruption, the higher usability. The implementation of the next generation MIS, which will help support the crucial operation procedure of the conglomerate and cope with the fast variation of the market demands.
76

Towards next-generation sequencing-based identification of norovirus recognition elements and microfluidic array using phage display technology / Phage Display als Tool zur Next Generation Sequencing-basierten Identifizierung von Norovirus-Erkennungselementen und zur Entwicklung eines mikrofluidischen Arrays

Pahlke, Claudia 28 November 2017 (has links) (PDF)
Noroviruses are the major cause of acute viral gastroenteritis worldwide. Thus, rapid and reliable pathogen detection and control are crucial to avoid epidemic outbreaks. Peptides which bind to these viruses with high specificity and affinity could serve as small and stable recognition elements in biosensing applications for a point-of-care diagnostic of noroviruses. They can be identified by screening large phage display libraries using the biopanning technique. In the present study, this method was applied to identify norovirus-binding peptide motifs. For this purpose, a biopanning based on column chromatography was established, and three rounds of selections were performed. After the second round, the cosmix-plexing recombination technique was implemented to enhance the chance of obtaining peptides with very high affinity. Biopanning data evaluation was based on next-generation sequencing (NGS), to show that this innovative method can enable a detailed analysis of the complete sequence spectrum obtained during and after biopanning. Highly enriched motifs could be characterized by their large proportion of the amino acids W, K, R, N, and F. Neighbourhood analysis was exemplarily performed for selected motifs, showing that the motifs FAT, RWN, and KWF possessed the fingerprints with the largest differences relative to the original library. This thesis thus presents next-generation sequencing-based analysis tools, which could now be transferred to any other biopanning project. The identified peptide motifs represent promising candidates for a future examination of their norovirus-specific binding. A new option for testing such phage-target interactions in the context of biopanning selections was studied in the second part of the thesis. For this purpose, a phage-based microarray was developed as a miniaturized binding assay. As a prerequisite, the different immobilization behaviour of phages on positively and negatively charged surfaces was studied, and a non-contact printing technique for bacteriophages was developed. Subsequently, the interaction of phages and antibodies directed against phage coat proteins was characterized in enzyme-linked immunosorbent assays, and the protocol was successfully transferred to the non-contact printed phage spots. At the proof-of-concept level, the phage array could finally be integrated into a microfluidic setup, showing a higher signal-to-background ratio relative to the static phage array. These results point the way towards a microfluidic phage array, allowing online monitoring, automation, and parallelisation of the phage array analysis. / Noroviren gelten als Hauptursache akuter viraler Magen-Darm-Erkrankungen. Nur eine zeitnahe und verlässliche Detektion und Kontrolle dieser Pathogene kann epidemische Ausbrüche vermeiden. Um dies zu ermöglichen, könnten Peptide, die an diese Viren mit hoher Spezifität und Affinität binden, als kleine und stabile Erkennungselemente in biosensorischen Anwendungen eingesetzt werden. Solche Peptide können mithilfe der Biopanning-Technik identifiziert werden, die auf dem Screening großer Phagen-Display-Bibliotheken beruht. In der vorliegenden Arbeit wurde diese Methode genutzt, um Norovirus-bindende Peptidmotive zu identifizieren. Dazu wurde ein auf Säulenchromatographie basierendes Biopanning entwickelt und drei Selektionsrunden durchgeführt. Die Cosmix-Plexing-Rekombinationstechnik wurde nach der zweiten Runde eingesetzt, um die Wahrscheinlichkeit der Gewinnung hochaffiner Binder zu erhöhen. Die Auswertung der Biopanningdaten erfolgte mittels Hochdurchsatzsequenzierung (Next-Generation Sequencing). Es konnte gezeigt werden, dass diese innovative Methode die detailierte Analyse des kompletten Sequenzspektrums während und nach dem Biopanning ermöglicht. Stark angereicherte Motive konnten durch ihren hohen Anteil an den Aminosäuren W, K, R, N und F charakterisiert werden. Eine Nachbarschaftsanalyse wurde exemplarisch für ausgewählte Motive durchgeführt. Dabei wurden die stärksten Unterschiede im Fingerprint im Vergleich zur Ausgangsbibliothek bei den Motiven FAT, RWN und KWF gefunden. Diese Dissertation stellt damit auf Next-Generation Sequencing basierende Analysetechniken vor, die für weitere Biopanningprojekte übernommen werden können. Die identifizierten Peptidmotive könnten als vielversprechende Kandidaten zukünftig auf ihre Norovirus-spezifische Bindung hin getestet werden. Eine neue Möglichkeit, solche Phagen-Analyt-Interaktionen zu untersuchen, wurde im zweiten Teil der Dissertation untersucht. Dafür wurde als miniaturisierter Bindungsassay ein Phagen-basiertes Mikroarray entwickelt. Als Voraussetzung wurde zunächst das unterschiedliche Immobilisierungsverhalten von Bakteriophagen auf positiv und negativ geladenen Oberflächen untersucht und eine kontaktfreie Drucktechnik für Bakteriophagen etabliert. Anschließend wurde die Interaktion von Phagen und gegen sie gerichteten Antikörpern in Enzym-gekoppelten Immunadsorptionstests charakterisiert und das Protokoll erfolgreich auf die kontaktfrei gedruckten Phagenspots übertragen. Schließlich wurde erstmals die grundsätzliche Möglichkeit gezeigt, das Array in ein mikrofluidisches Setup zu integrieren, was zu einem höheren Signal-zu-Hintergrund-Verhältnis im Vergleich zum statischen Array führte. Diese Ergebnisse zeigen damit den Weg zu einem mikrofluidischen Phagen-Array auf, das sowohl die Möglichkeit des Online-Monitorings als auch der Automatisierung und Parallelisierung der Phagen-Array-Analyse bietet.
77

Nachtrag zur Veranstaltung „Keine Sackgasse: Schnelles Internet und Straßenausbau im kommunalen Fokus“

Kilian, Maike 13 June 2019 (has links)
Die Verfügbarkeit von Breitbandnetzen wird für die Sicherung und Weiterentwicklung des Wirtschafts-, Technologie- und Tourismusstandortes Sachsen immer wichtiger. Eine gute Nachricht gleich zu Beginn: Das Land Sachsen stellt seit Ende letzten Jahres Fördermittel für den Aufbau von Breitbandnetzen auch für die zukunftsfähigen Next-Generation-Access-Netze (NGA) zur Verfügung. Zuwendungsempfänger sind neben Gemeinden, Landkreisen, Verwaltungsgemeinschaften und Gemeindeverbände auch Eigenbetriebe und Zweckverbände. Das ließ viele Zuhörer auf der Informationsveranstaltung „Breitband und Straßen als kommunale Herausforderung“ am 26. März 2015 in Leipzig aufhorchen.
78

A critical appraisal of the European Commission´s policy towards regulating next generation communications networks

Briglauer, Wolfgang, Gugler, Klaus January 2012 (has links) (PDF)
Fiber-deployment of telecommunications networks is currently a great challenge for sector-specific regulators, national governments, as well as for investing operators. One of the most controversial regulatory issues in Europe (and elsewhere) is whether the emerging next generation access (NGA) infrastructure should be subjected to cost-based access regulation or whether at least a temporary removal of ex ante obligations ("regulatory holidays") should be granted. In answering this question we examine the current and foreseeable EU regulatory framework and show that it does not provide positive incentives for NGA deployment and increasing penetration rates. On the basis of an international comparison with the most recent data on NGA deployment and penetration, it appears, in turn, that deregulatory and/or state aid driven approaches targeted at the demand (subscribers) and supply side (coverage) are more promising. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
79

Efficient contracts for government intervention in promoting next generation communications networks

Briglauer, Wolfgang, Holzleitner, Christian 07 1900 (has links) (PDF)
Although the future socio-economic benefits of a new fibre-based ("next generation access", NGA) telecommunications infrastructure seem to be uncontroversial, most countries have to date only undertaken NGA investments on a small scale. Accordingly, a universal NGA coverage appears to be a rather unrealistic objective without government intervention. Indeed, many governments have already initiated diverse subsidy programs in order to stimulate NGA infrastructure deployment. We contend, however, that the current contract practice of fixing ex ante targets for network expansion is inefficient given the uncertainty about future returns on NGA infrastructure-based services and the public authorities' incomplete information about the capital costs of the network provider. This paper puts forward to delegate the choice of the network expansion to the NGA provider. Simple linear profit-sharing contracts can be designed to control the NGA provider's incentives and to put in balance the public objectives of network expansion and limitation of public expenditure. (author's abstract) / Series: Working Papers / Research Institute for Regulatory Economics
80

Formalization of a converged internet and telecommunications service environment

Blum, Niklas January 2010 (has links)
The programmable network envisioned in the 1990s within standardization and research for the Intelligent Network is currently coming into reality using IPbased Next Generation Networks (NGN) and applying Service-Oriented Architecture (SOA) principles for service creation, execution, and hosting. SOA is the foundation for both next-generation telecommunications and middleware architectures, which are rapidly converging on top of commodity transport services. Services such as triple/quadruple play, multimedia messaging, and presence are enabled by the emerging service-oriented IPMultimedia Subsystem (IMS), and allow telecommunications service providers to maintain, if not improve, their position in the marketplace. SOA becomes the de facto standard in next-generation middleware systems as the system model of choice to interconnect service consumers and providers within and between enterprises. We leverage previous research activities in overlay networking technologies along with recent advances in network abstraction, service exposure, and service creation to develop a paradigm for a service environment providing converged Internet and Telecommunications services that we call Service Broker. Such a Service Broker provides mechanisms to combine and mediate between different service paradigms from the two domains Internet/WWW and telecommunications. Furthermore, it enables the composition of services across these domains and is capable of defining and applying temporal constraints during creation and execution time. By adding network-awareness into the service fabric, such a Service Broker may also act as a next generation network-to-service element allowing the composition of crossdomain and cross-layer network and service resources. The contribution of this research is threefold: first, we analyze and classify principles and technologies from Information Technologies (IT) and telecommunications to identify and discuss issues allowing cross-domain composition in a converging service layer. Second, we discuss service composition methods allowing the creation of converged services on an abstract level; in particular, we present a formalized method for model-checking of such compositions. Finally, we propose a Service Broker architecture converging Internet and Telecom services. This environment enables cross-domain feature interaction in services through formalized obligation policies acting as constraints during service discovery, creation, and execution time. / Das programmierbare Netz, das Ende des 20. Jahrhunderts in der Standardisierung und Forschung für das Intelligente Netz entworfen wurde, wird nun Realität in einem auf das Internet Protokoll basierendem Netz der nächsten Generation (Next Generation Network). Hierfür kommen Prinzipien aus der Informationstechnologie, insbesondere aus dem Bereich dienstorientierte Architekturen (Service-Oriented Architecture / SOA) für die Diensterstellung, -ausführung und -betrieb zum Tragen. SOA bietet hierbei die theoretische Grundlage für Telekommunikationsnetze, vor allem jedoch für die dazugehörigen Dienstplattformen. Diese erlauben dem Telekommunikationsbetreiber seine Position in einem offenen Marktplatz der Dienste auszubauen. Dazu bedarf es allerdings möglichst flexibler Dienstumgebungen, die die Kooperation zwischen Dienstanbietern und Nutzern aus unterschiedlichsten Domänen durch Unterstützung geeigneter Werkzeuge und Mechanismen fördert. Im Rahmen dieser Dissertation definieren wir aufbauend auf Forschungsergebnisse im Bereich Overlay-Netze, Netzabstraktion und Zugriff auf exponierte Dienste eine Service Broker genannte Dienstumgebung für konvergente Internet- und Telekommunikationsdienste. Dieser Service Broker stellt Mechanismen für die Komposition von Diensten und Mediation zwischen unterschiedlichen Dienstparadigmen und Domänenspezifika beim Dienstaufruf zur Verfügung. Der Forschungsbeitrag dieser Arbeit findet auf unterschiedlichen Ebenen statt: Aufbauend auf einer Analyse und Klassifikation von Technologien und Paradigmen aus den Bereichen Informationstechnologie (IT) und Telekommunikation diskutieren wir die Problemstellung der Kooperation von Diensten und deren Komposition über Domänengrenzen hinweg. In einem zweiten Schritt diskutieren wir Methoden der Dienstkomposition und präsentieren eine formalisierte Methode der modellbasierten Diensterstellung. Der Schwerpunkt der Arbeit liegt auf der Spezifikation der Service Broker Dienstumgebung und einem zugrundeliegenden Informations- und Datenmodell. Diese Architektur erlaubt die Komposition und Kooperation von Diensten über Domänengrenzen hinweg, um konvergente Internet- und Telekommunikationsdienste zu realisieren. Hierfür wird ein auf Obligationspolitiken basierendes Regelsystemformalisiert, das Interaktionen zwischen Dienstmerkmalen während der Diensterstellung und -ausführung definiert.

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