• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 4
  • 3
  • Tagged with
  • 12
  • 12
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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

Über die Bedeutung von Melodie und Rhythmus in der vorsprachlichen Entwicklung von Säuglingen unter besonderer Berücksichtigung der spezifischen Bedürfnisse von Kindern mit orofazialen Spalten - ein Beitrag zur Entwicklung geeigneter Frühförderkonzepte / On the importance of melody and rhythm in the pre-linguistic development of infants with special consideration on the specific needs of children with orofacial clefts - a contribution on the development of suitable early stimulation concepts

Dokou, Panagiota January 2007 (has links) (PDF)
In den letzten Jahren sind verschiedene Studien erschienen, die die positive Wirkung von Musik zur Frühförderung von Kindern untersucht haben. Im Sinne dieser Studien wurden auch verschiedene Therapieprogramme, die auf traditionellen musiktherapeutischen Konzepten basieren, entwickelt. Neueste Arbeiten unterstützen eine spezifische Wirkung der musikalischen Frühförderung: sie kann den Spracherwerb fördern. Säuglinge mit orofazialen Spalten arbeiten z. B. in einer Klinik in Los Angeles, USA, mit Hilfe von Musik an ihren Sprachproblemen. Die vorliegende Arbeit hatte das Ziel auf der Basis moderner Erkenntnisse der Neuro- und Kognitionswissenschaften Argumente für die positive Wirkung von musikalischer Frühförderung auf den Spracherwerb bei Kindern mit orofazialen Spalten zusammenzutragen und einen solchen Ansatz durch wissenschaftliche Ergebnisse zu begründen. Die spezifische Wirkung von Musik auf den Spracherwerb, so konnte gezeigt werden, basiert u. a. auf folgenden Befunden: a. Es existieren gemeinsame hirnphysiologische Produktions- und Verarbeitungsmechanismen von Melodie und Rhythmus in der Musik und der gesprochenen Sprache. b. Prosodische Elemente der Sprache, wie die Melodie und der Rhythmus, werden unter starker Beteiligung der rechten Hemisphäre verarbeitet. So konnte u. a. gezeigt werden, dass hirnphysiologische Reaktionen bei jungen Musikschülern (Thomanerchor) auf sprachliche Syntaxverletzungen stärker ausfallen als bei gleichaltrigen Nichtmusikern. c. Die rechte Hemisphäre, in der auch Musik verarbeitet wird, ist bei der vorsprachlichen Lautproduktion der Säuglinge die dominierende. Es gibt große Ähnlichkeiten bei der zerebralen Verarbeitung von Melodie und Rhythmus von „Säuglingssprache“ und Musik. d. Neuere hirnphysiologische Untersuchungen belegen, dass ein musikalisches Training nachweislich funktionelle Korrelate in bestimmten Gehirnregionen zeigt und eine positive Wirkung auf den Spracherwerbprozess auszuüben scheint. Es konnte gezeigt werden, dass überlappende Verarbeitungsregionen in beiden Gehirnhälften, sowohl für musikalische als auch für sprachliche Informationen verantwortlich sind. Die Ergebnisse neuer Forschungen, die eine starke Beteiligung der rechten Hemisphäre in der Verarbeitung prosodischer Charakteristiken der Sprache, wie z. B. die Melodie und der Rhythmus belegen, wurden dargestellt und die alte Ansichten über eine ausschließliche Verarbeitung sprachlicher Informationen in der linken Hemisphäre wurden widerlegt. Die Bedeutung der rechten Gehirnhälfte für die vorsprachliche Lautproduktion der Säuglinge wurde herausgearbeitet und daraus der Nutzen einer intensiven akustischen Förderung unter Anwendung speziell entwickelte Stimuli, für eine korrekte spätere Sprachentwicklung bei Kindern mit orofazialen Spalten abgeleitet. Die Auswahl der Musik sollte sich an den in der Arbeit beschriebenen musikalischen Verarbeitungsleistungen der Säuglinge orientieren, um eine individuelle und auf die Bedürfnisse jedes Säuglings mit orofazialer Spalte angepasste musikalische Stimulation zu erreichen. Diese Bedürfnisse können anhand der vorsprachlichen Entwicklungsprofile, wie sie für jeden Säugling am ZVES (Zentrum für vorsprachliche Entwicklung und Entwicklungsstörungen) erstellt werden, charakterisiert werden. Im Ergebnis der umfangreichen Literaturstudien zu allen für das gestellte Thema relevanten Aspekten und unter Verwendung der im ZVES gesammelten praktischen Erfahrungen wurde eine Forschungskonzeption zum Nachweis der Wirkung einer musikalischern Frühförderung auf den Spracherwerb erarbeitet. Für Säuglinge mit orofazialen Spalten ist eine individuelle Therapie notwendig, da sich die Kinder bezüglich ihrer individuellen Entwicklungsbedingungen stark unterschieden. / Over the last years diverse studies were published, which examined the positive effect of music on the early stimulation of children. Therefore diverse therapy programs have been developed on the basis of traditional music therapy concepts. Latest studies support a specific effect of early musical stimulation; it stimulates the language acquisition. For example in a clinic in Los Angeles (USA), infants with orofacial clefts work with the help of music on their linguistic disabilities. This study aimed to collect arguments for the positive effect of early musical stimulation on the language acquisition of children with orofacial clefts and to justify this claim through scientific results, on the basis of modern findings of the neuro and cognition sciences. The specific effect of music on the language acquisition is based on the following results: a. Common brain physiological production and processing mechanisms of melody and rhythm exist in both music and language. b. Prosodic elements of language such as melody and rhythm are being processed under strong participation of the right hemisphere. It has been shown, that the brain’s physiological reactions in young music students (Thomanerchor) to linguistic syntax violations were more intense than those of non-musicians of the same age. c. The right hemisphere, where music is also being processed, dominates the pre-linguistic tone production of infants. Great resemblances exist between the cerebral processing of melody and rhythm in “infants’ language” and music. d. New brain physiological researches verified that musical training shows evidently functional correlates in certain brain regions and therefore could have a positive effect on the language acquisition process. It has been shown, that overlapping processing regions in both hemispheres are responsible not only for musical but also for linguistic information. The results of latest scientific research which showed an intensive participation of the right hemisphere in the processing of prosodic features of language (such as melody and rhythm) were thoroughly described and the old views of the exclusive processing of linguistic information in the left hemisphere were refuted. The importance of the right hemisphere for the pre-linguistic tone production of infants has been brought out and the advantage of an intensive acoustic stimulation with the use of special developed stimuli for a correct later language acquisition development by children with orofacial clefts could also be derived through this knowledge. The selection of the musical stimuli should be based on the musical processing performance of infants (which were described in this study) so that the individual needs of each infant with cleft-lip and palate for adjusted musical stimulation can be met. These needs can be characterized on the basis of pre-linguistic development profiles, such as those that are produced for every infant at the ZVES (Center for Pre-linguistic Development and Development Disorders). As a result of extensive literature studies with aspects relevant to this theme and taking into account the practical experience accumulated at the ZVES, a research conception can be worked out as proof of the effect an early musical stimulation has on language acquisition. For the infants with orofacial clefts an individual therapy is made necessary by the specialized development conditions of these children.
2

Visuelle Gesichtswahrnehmung von unilateralen Lippen-Kiefer-Gaumenspaltpatienten und Dysgnathiepatienten mit skelettaler Klasse III im Vergleich zu einer Kontrollgruppe / Face perception in patients with unilateral cleft lip and palate and patients with severe Class III malocclusion compared to controls

Herget, Claudia January 2011 (has links) (PDF)
ZIEL: Obwohl ein Zusammenhang zwischen Gesichtsasymmetrie und fazialer Attraktivität eines Menschen zu bestehen scheint, gibt es bislang keine Studien, die einen Vergleich der Gesichtswahrnehmung durch Laien zwischen Patienten mit einseitiger Lippen-Kiefer-Gaumenspalte, einer Dysgnathie der Klasse III und einer Kontrollgruppe analysieren. PATIENTEN UND METHODE: Von 30 erwachsenen einseitigen Lippen-Kiefer-Gaumenspaltpatienten, 20 Patienten mit einer Dysgnathie der skelettaler Klasse III und 20 Erwachsenen mit einer skelettalen Klasse I wurden 3D-Gesichtsdaten mittels einem lichtoptischen System sowie standardisierte extraorale Aufnahmen angefertigt. Der objektive 3D Asymmetriegrad wurde vom Gesamtgesicht berechnet. Die subjektive Beurteilung der Attraktivität wurde von einer Beurteilergruppe, bestehend aus 100 Layen, randomisiert erfasst. ERGEBNISSE: Im Vergleich zur Kontrollgruppe wiesen die Patienten mit uLKG-Spalte und die Patienten mit einer Dysgnathie der Klasse III einen signifikant größeren fazialen Asymmetriegrad auf. Zwischen den Patienten mit uLKG-Spalte und den Patienten mit einer Dysgnathie konnte kein Unterschied in der Gesichtsasymmetrie festgestellt werden. Die subjektive Bewertung der Attraktivität zeigte, dass Patienten mit uLKG-Spalte und Patienten mit einer Dysgnathie unattraktiver auf die Beurteiler wirkten, als die Kontrollpersonen. Obwohl kein Unterschied in der fazialen Asymmetrie zwischen den Patienten mit uLKG-Spalte und den Patienten mit einer Dysgnathie bestand, wurden die Patienten mit uLKG-Spalte als signifikant weniger attraktiv bewertet. SCHLUSSFOLGERUNG: Die subjektive Beurteilung der Gesichter wird nicht nur durch das Ausmaß der Gesichtsasymmetrie beeinflusst, sondern ebenfalls durch die Lokalisation der Asymmetrie. Dies ist vor allem für den Kliniker von großer Wichtigkeit, der für eine bestmögliche operative Rekonstruktion der Nasenmorphologie bei Patienten mit uLKG-Spalte verantwortlich ist. / OBJECTIVE:Although there is principal agreement that increased facial asymmetry is associated with decreased facial attractiveness, there are no studies analysing face perception in patients with a unilateral cleft lip and palate (CLP) (uCLP) compared to orthognathic Class III patients. PATIENTS AND METHODS: To this end, three-dimensional (3D) data on the faces of 30 adults with a complete uCLP, 20 orthognathic patients with a severe skeletal Class III, and 20 adults with a skeletal Class I as a control group were generated. The 3D asymmetry of the facial soft-tissue was analysed. These data were compared with subjective ratings for attractiveness carried out by 100 laypersons. RESULTS: Compared to the controls, uCLP patients and orthognathic patients had a significantly higher facial asymmetry. No difference was found between uCLP patients and orthognathic patients. The attractiveness ratings showed that uCLP patients and orthognathic patients were rated less attractive compared to the controls. However, although there were no differences in the facial asymmetry between uCLP patients and orthognathic patients, the uCLP patients were rated significantly less attractive. CONCLUTION: This leads to the conclusion that not only the extent of asymmetry has an influence on attractiveness but also the location of asymmetry. For clinical use, these findings underline the importance of accurate as possible surgical reconstruction of the nasal morphology in uCLP patients.
3

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.
4

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.
5

Theoretische und experimentelle Untersuchung des spaltungsinduzierten Versagens von TRC Prüfkörpern

Schoene, Jens, Reisgen, Uwe, Schleser, Markus, Jeřábek, Jakub 01 December 2011 (has links) (PDF)
Bewehrungen mit einer hochmoduligen Polymertränkung erreichen im Betonbauteil Textilspannungen von über 1200 N/mm². Ab diesem Niveau wurden in Dehnkörperversuchen Längsrisse und Betonabplatzungen beobachtet. Für die Eingrenzung und Identifikation der elementaren, verantwortlichen Mechanismen weisen großformatige Dehnkörper störende Einflüsse von Randeffekten und Imperfektionen auf. Daher wurde ein neuer Versuchsaufbau entwickelt, bestehend aus einem in einen Betonquader eingebetteten Einzelroving. Die simple Herstellung und die Verlässlichkeit dieser Kategorie von Experimenten in Bezug auf die Reproduzierbarkeit und der geringen Streuung der Resultate machen sie zu einer robusten Grundlage für experimentelle Untersuchungen des Verhaltens von TRC. Die experimentell ermittelten Bruchlasten werden zunächst bezüglich ihrer Leistung diskutiert und dann die beobachteten Bruchvorgänge kategorisiert hinsichtlich kompatibler mechanischer Hypothesen für die Initiierung von Längsrissen und des Spaltversagen. / Reinforcements with a high-modulus, polymeric impregnation achieve textile tensions of 1200 N/mm² and more in concrete parts. Starting at this level longitudinal cracks and splitting were observed in tests. In order to isolate and identify the fundamental, responsible mechanisms large-scale specimen show an interfering impact of boundary effects and imperfections. Therefore a new test set-up was developed, consisting of a single roving embedded in a single concrete cuboid. The simplicity of production and reliability of this class of experiments in terms of repeatability and low scatter of results makes them a robust basis for experimental investigation of TRC behavior. The experimentally obtained strengths are discussed in terms of the performance, followed by the categorization of observed failure patterns with respect to the available mechanical hypotheses of the longitudinal crack initiation and splitting failure.
6

Graph Processing in Main-Memory Column Stores

Paradies, Marcus 29 May 2017 (has links) (PDF)
Evermore, novel and traditional business applications leverage the advantages of a graph data model, such as the offered schema flexibility and an explicit representation of relationships between entities. As a consequence, companies are confronted with the challenge of storing, manipulating, and querying terabytes of graph data for enterprise-critical applications. Although these business applications operate on graph-structured data, they still require direct access to the relational data and typically rely on an RDBMS to keep a single source of truth and access. Existing solutions performing graph operations on business-critical data either use a combination of SQL and application logic or employ a graph data management system. For the first approach, relying solely on SQL results in poor execution performance caused by the functional mismatch between typical graph operations and the relational algebra. To the worse, graph algorithms expose a tremendous variety in structure and functionality caused by their often domain-specific implementations and therefore can be hardly integrated into a database management system other than with custom coding. Since the majority of these enterprise-critical applications exclusively run on relational DBMSs, employing a specialized system for storing and processing graph data is typically not sensible. Besides the maintenance overhead for keeping the systems in sync, combining graph and relational operations is hard to realize as it requires data transfer across system boundaries. A basic ingredient of graph queries and algorithms are traversal operations and are a fundamental component of any database management system that aims at storing, manipulating, and querying graph data. Well-established graph traversal algorithms are standalone implementations relying on optimized data structures. The integration of graph traversals as an operator into a database management system requires a tight integration into the existing database environment and a development of new components, such as a graph topology-aware optimizer and accompanying graph statistics, graph-specific secondary index structures to speedup traversals, and an accompanying graph query language. In this thesis, we introduce and describe GRAPHITE, a hybrid graph-relational data management system. GRAPHITE is a performance-oriented graph data management system as part of an RDBMS allowing to seamlessly combine processing of graph data with relational data in the same system. We propose a columnar storage representation for graph data to leverage the already existing and mature data management and query processing infrastructure of relational database management systems. At the core of GRAPHITE we propose an execution engine solely based on set operations and graph traversals. Our design is driven by the observation that different graph topologies expose different algorithmic requirements to the design of a graph traversal operator. We derive two graph traversal implementations targeting the most common graph topologies and demonstrate how graph-specific statistics can be leveraged to select the optimal physical traversal operator. To accelerate graph traversals, we devise a set of graph-specific, updateable secondary index structures to improve the performance of vertex neighborhood expansion. Finally, we introduce a domain-specific language with an intuitive programming model to extend graph traversals with custom application logic at runtime. We use the LLVM compiler framework to generate efficient code that tightly integrates the user-specified application logic with our highly optimized built-in graph traversal operators. Our experimental evaluation shows that GRAPHITE can outperform native graph management systems by several orders of magnitude while providing all the features of an RDBMS, such as transaction support, backup and recovery, security and user management, effectively providing a promising alternative to specialized graph management systems that lack many of these features and require expensive data replication and maintenance processes.
7

Graph Processing in Main-Memory Column Stores

Paradies, Marcus 03 February 2017 (has links)
Evermore, novel and traditional business applications leverage the advantages of a graph data model, such as the offered schema flexibility and an explicit representation of relationships between entities. As a consequence, companies are confronted with the challenge of storing, manipulating, and querying terabytes of graph data for enterprise-critical applications. Although these business applications operate on graph-structured data, they still require direct access to the relational data and typically rely on an RDBMS to keep a single source of truth and access. Existing solutions performing graph operations on business-critical data either use a combination of SQL and application logic or employ a graph data management system. For the first approach, relying solely on SQL results in poor execution performance caused by the functional mismatch between typical graph operations and the relational algebra. To the worse, graph algorithms expose a tremendous variety in structure and functionality caused by their often domain-specific implementations and therefore can be hardly integrated into a database management system other than with custom coding. Since the majority of these enterprise-critical applications exclusively run on relational DBMSs, employing a specialized system for storing and processing graph data is typically not sensible. Besides the maintenance overhead for keeping the systems in sync, combining graph and relational operations is hard to realize as it requires data transfer across system boundaries. A basic ingredient of graph queries and algorithms are traversal operations and are a fundamental component of any database management system that aims at storing, manipulating, and querying graph data. Well-established graph traversal algorithms are standalone implementations relying on optimized data structures. The integration of graph traversals as an operator into a database management system requires a tight integration into the existing database environment and a development of new components, such as a graph topology-aware optimizer and accompanying graph statistics, graph-specific secondary index structures to speedup traversals, and an accompanying graph query language. In this thesis, we introduce and describe GRAPHITE, a hybrid graph-relational data management system. GRAPHITE is a performance-oriented graph data management system as part of an RDBMS allowing to seamlessly combine processing of graph data with relational data in the same system. We propose a columnar storage representation for graph data to leverage the already existing and mature data management and query processing infrastructure of relational database management systems. At the core of GRAPHITE we propose an execution engine solely based on set operations and graph traversals. Our design is driven by the observation that different graph topologies expose different algorithmic requirements to the design of a graph traversal operator. We derive two graph traversal implementations targeting the most common graph topologies and demonstrate how graph-specific statistics can be leveraged to select the optimal physical traversal operator. To accelerate graph traversals, we devise a set of graph-specific, updateable secondary index structures to improve the performance of vertex neighborhood expansion. Finally, we introduce a domain-specific language with an intuitive programming model to extend graph traversals with custom application logic at runtime. We use the LLVM compiler framework to generate efficient code that tightly integrates the user-specified application logic with our highly optimized built-in graph traversal operators. Our experimental evaluation shows that GRAPHITE can outperform native graph management systems by several orders of magnitude while providing all the features of an RDBMS, such as transaction support, backup and recovery, security and user management, effectively providing a promising alternative to specialized graph management systems that lack many of these features and require expensive data replication and maintenance processes.
8

Theoretische und experimentelle Untersuchung des spaltungsinduzierten Versagens von TRC Prüfkörpern

Schoene, Jens, Reisgen, Uwe, Schleser, Markus, Jeřábek, Jakub January 2011 (has links)
Bewehrungen mit einer hochmoduligen Polymertränkung erreichen im Betonbauteil Textilspannungen von über 1200 N/mm². Ab diesem Niveau wurden in Dehnkörperversuchen Längsrisse und Betonabplatzungen beobachtet. Für die Eingrenzung und Identifikation der elementaren, verantwortlichen Mechanismen weisen großformatige Dehnkörper störende Einflüsse von Randeffekten und Imperfektionen auf. Daher wurde ein neuer Versuchsaufbau entwickelt, bestehend aus einem in einen Betonquader eingebetteten Einzelroving. Die simple Herstellung und die Verlässlichkeit dieser Kategorie von Experimenten in Bezug auf die Reproduzierbarkeit und der geringen Streuung der Resultate machen sie zu einer robusten Grundlage für experimentelle Untersuchungen des Verhaltens von TRC. Die experimentell ermittelten Bruchlasten werden zunächst bezüglich ihrer Leistung diskutiert und dann die beobachteten Bruchvorgänge kategorisiert hinsichtlich kompatibler mechanischer Hypothesen für die Initiierung von Längsrissen und des Spaltversagen. / Reinforcements with a high-modulus, polymeric impregnation achieve textile tensions of 1200 N/mm² and more in concrete parts. Starting at this level longitudinal cracks and splitting were observed in tests. In order to isolate and identify the fundamental, responsible mechanisms large-scale specimen show an interfering impact of boundary effects and imperfections. Therefore a new test set-up was developed, consisting of a single roving embedded in a single concrete cuboid. The simplicity of production and reliability of this class of experiments in terms of repeatability and low scatter of results makes them a robust basis for experimental investigation of TRC behavior. The experimentally obtained strengths are discussed in terms of the performance, followed by the categorization of observed failure patterns with respect to the available mechanical hypotheses of the longitudinal crack initiation and splitting failure.
9

Synthese-Eigenschafts-Beziehungen von mikro-/mesoporösen Alumosilicaten und deren Mischphasen bei der Umsetzung von Oxygenaten

Gille, Torsten 16 June 2020 (has links)
Diese Arbeit befasst sich mit der katalytischen Umsetzung von oxygenierten Kohlenwasserstoffen in einem Strömungsrohrreaktor bei 500 °C an mikroporösem Alumosilicat ZSM-5, an dem mesoporösem Alumosilicat Al-MCM-41 sowie an deren Mischphasen. Anhand der katalytischen Untersuchungen ist es möglich, für verschiedene Anforderungen an das Produktspektrum Empfehlungen an die Eigenschaften des zu verwendeten Katalysatorsystems zu formulieren. Hierfür wurden Untersuchungen zum Einfluss relevanter Syntheseprozessparameter auf die Zusammensetzung von Al-MCM-41/ZSM-5-Mischphasen vorgenommen. Die Synthese solcher Mischphasen wurde über einen 'Zwei-Template/Ein-Schritt“-Ansatz durchgeführt, der es erlaubte, die an das Katalysatorsystem gestellten Anforderungen durch eine geeignete Wahl der Syntheseparameter zu genügen. Während der Synthese der Al-MCM-41/ZSM-5-Mischphasen beobachtet man drei sich gegenseitig beeinflussenden Vorgänge, die durch, in der wässrigen Syntheselösung vorliegende, alumosilicatische Komponenten miteinander verknüpft sind: Die Auflösung und anschließende Restrukturierung einer nicht-porösen amorphen Phase, die Auflösung und Restrukturierung einer mesoporösen Al-MCM-41-Phase und die Kristallisation einer mikroporösen ZSM-5-Phase. Durch die Erhöhung des Al-Anteils im Synthesegel werden die ZSM-5-Kristallisation verlangsamt und der Schwerpunkt des Gleichgewichts dieser drei Vorgänge für einen gegebenen Reaktionszeitpunkt in Richtung der Bildung der mesoporösen Al-MCM-41-Phase verlagert. Der Einfluss des, in das jeweilige Katalysatorsystem eingebauten Aluminiums auf die katalytische Umsetzung von Oxygenaten manifestiert sich für die beiden Alumosilicate ZSM¬ 5 und Al MCM-41 auf verschiedene Weise. Eine Erhöhung des Al-Anteils in einem mikroporösen ZSM-5-Katalysatorsystem begünstigt den Verlauf von bimolekularen Reaktionen. Dies äußert sich in einem verstärkten Auftreten von Paraffin-bildenden Raktionen wie die Wasserstoff-Transfer-Reaktionen und/oder die Carboniumionen-Spaltung sowie in einer Dominanz von Aromaten-bildenen Reaktionen wie die Cyclisierung mit anschließender Dehydrierung und Aromatisierung. Dieser Effekt kann bei einer Erhöhung des Al-Anteils in einem mesoporösen Al-MCM-41-Katalysatorsystem nur im geringen Maße beobachtet werden. Jedoch nimmt mit sinkendem Si/Al-Verhältnis in beiden Katalysatorsystemen der Anteil an Produkten mit drei oder vier Kohlenstoffatomen zu. Zudem kann dabei eine beginnende Unabhängigkeit des gebildeten Produktspektrums von der Kettenlänge und der funktionellen Gruppe des umgesetzten Oxygenats beobachtet werden.:Inhaltsverzeichnis 1 Einleitung und Problemstellung 1 2 Grundlagen 4 2.1 Hydrothermale Synthese von Alumosilicaten 4 2.1.1 WÄSSRIGE CHEMIE UND HYDROTHERMALE BEHANDLUNG VON ALUMOSILICATEN 4 2.1.2 STRUKTUR UND BILDUNGSMECHANISMUS VON AL-MCM-41 5 2.1.3 STRUKTUR UND BILDUNGSMECHANISMUS VON ZSM-5 6 2.2 Katalytische Spaltung von Kohlenwasserstoffen an Alumosilicaten 9 2.2.1 NATUR UND LOKALISIERUNG VON SÄUREZENTREN 9 2.2.2 KOHLENWASSERSTOFF-POOL-MECHANISMUS UND VERKOKUNG 10 3 Experimentelles Vorgehen und analytische Messverfahren 14 3.1 Syntheseroute zur Herstellung von Al MCM 41/ZSM 5-Mischphasen, Al MCM 41 und ZSM-5 14 3.1.1 AL MCM 41/ZSM 5 MISCHPHASEN 14 3.1.2 AL-MCM-41 17 3.1.3 ZSM-5 17 3.2 Datenerhebung und -auswertung relevanter physikalisch-chemischer und festkörperanalytischer Charakterisierungsmethoden 17 3.2.1 PULVER-RÖNTGENDIFFRAKTOMETRIE 17 3.2.2 N2-PHYSISORPTION 19 3.2.3 TEMPERATUR-PROGRAMMIERTE AMMONIAK-DESORPTION 21 3.2.4 ELEMENTARANALYSE 23 3.2.5 27AL MAS NMR 24 3.2.6 THERMOGRAVIMETRISCHE ANALYSE 25 3.3 Katalytische Austestung und Analyse der Messdaten 26 3.3.1 VERSUCHSDURCHFÜHRUNG 26 3.3.2 ANALYSE UND AUSWERTUNG KATALYTISCHER MESSDATEN 27 3.3.3 DURCHGEFÜHRTE KATALYTISCHE TESTMESSUNGEN 29 4 Untersuchungen zum Bildungsmechanismus von Al MCM 41/ZSM 5-Mischphasen 33 4.1 Mechanistische Deutung 33 4.1.1 VORBETRACHTUNG 33 4.1.2 REAKTIONSABLAUF 34 4.1.3 UNTERSUCHUNG DER MESOPOROSITÄT 39 4.1.4 MORPHOLOGISCHE BETRACHTUNG 43 4.2 Wechselwirkungen der „Beeinflussungsfaktoren“ 45 4.2.1 EFFEKT VERSCHIEDENER AUTOKLAV-TYPEN 45 4.2.2 EFFEKT DES AL-ANTEILS IM SYNTHESEGEL 48 4.2.3 SYMBIOTISCHE EINFLUSSNAHME VON ALUMINIUM UND TENSIDEN 50 5 Charakterisierung verwendeter Katalysatormaterialien 52 5.1 ZSM-5 52 5.2 Al-MCM-41 57 5.3 Physikalische Mischungen aus Al-MCM-41 und ZSM-5 60 6 Katalytisches Spalten von Oxygenaten an ZSM 5 64 6.1 Katalytisches Spalten von Alkohol-Oxygenaten an ZSM 5 in Abhängigkeit des Si/Al Verhältnisses 64 6.1.1 PRODUKTANALYSE ANHAND DER KOHLENSTOFFANZAHL IM PRODUKTMOLEKÜL 65 6.1.2 PRODUKTANALYSE ANHAND EINZELNER STOFFGRUPPEN 68 6.2 Katalytisches Spalten von Carbonyl-Oxygenaten an ZSM 5 in Abhängigkeit des Si/Al Verhältnisses 71 6.2.1 PRODUKTANALYSE ANHAND DER KOHLENSTOFFANZAHL IM PRODUKTMOLEKÜL 72 6.2.2 PRODUKTANALYSE ANHAND EINZELNER STOFFGRUPPEN 76 6.3 Ableitung eines Kohlenwasserstoff-Pool Mechanismus zur Beschreibung des katalytischen Spaltens von Oxygenaten an ZSM 5 80 6.3.1 VEREINHEITLICHUNG DES OXYGENAT FEEDS ÜBER DESSEN DEOXYGENIERUNG 81 6.3.2 ASSIMILATION KURZKETTIGER OLEFINE DURCH EINEN KATALYTISCH AKTIVEN BEREICH 83 6.3.3 EINFLUSS DES PORENSYSTEMS UND AL-ANTEILS IM KATALYSATORSYSTEMS 85 6.3.4 BESCHREIBUNG DER PRODUKTBILDUNG EINZELNER STOFFGRUPPEN IN ABHÄNGIGKEIT WESENTLICHER REAKTIONSBEDINGUNGEN 87 7 Katalytisches Spalten von Triacylglyceriden an Al MCM 41 und physikalischen Mischungen aus Al-MCM-41 und ZSM-5 92 7.1 Gegenüberstellung des katalytischen Spaltens von Ethyloctanoat an Al MCM 41 und ZSM 5 in Abhängigkeit des Si/Al Verhältnisses 92 7.2 Anwendung des Kohlenwasserstoff-Pool Mechanismus zur Beschreibung des katalytischen Spaltens von Triacylglyceriden an physikalischen Mischungen aus Al MCM-41 und ZSM-5 97 7.3 Synthese-Struktur-Wirkungsprinzip 103 8 Zusammenfassung und Ausblick 106 Literatur 112 Abbildungsverzeichnis 127 Tabellenverzeichnis 139 Abkürzungsverzeichnis 141 Anhang 142 Veröffentlichungen 165 Eidesstattliche Erklärung 168
10

Partition-based SIMD Processing and its Application to Columnar Database Systems

Hildebrandt, Juliana, Pietrzyk, Johannes, Krause, Alexander, Habich, Dirk, Lehner, Wolfgang 19 March 2024 (has links)
The Single Instruction Multiple Data (SIMD) paradigm became a core principle for optimizing query processing in columnar database systems. Until now, only the LOAD/STORE instructions are considered to be efficient enough to achieve the expected speedups, while avoiding GATHER/SCATTER is considered almost imperative. However, the GATHER instruction offers a very flexible way to populate SIMD registers with data elements coming from non-consecutive memory locations. As we will discuss within this article, the GATHER instruction can achieve the same performance as the LOAD instruction, if applied properly. To enable the proper usage, we outline a novel access pattern allowing fine-grained, partition-based SIMD implementations. Then, we apply this partition-based SIMD processing to two representative examples from columnar database systems to experimentally demonstrate the applicability and efficiency of our new access pattern.

Page generated in 0.05 seconds