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

Propagation Patterns of News on Twitter : A Study in How News Propagate Through Twitter Via the Use of Bitly Links. / Spridningsmönster hos nyheter på Twitter : En studie i hur nyheter propagerar på Twitter via Bitly-länkar.

Lundström, Linnea, Ragnarsson, Sebastian January 2018 (has links)
As so called fake news spread widely on the internet it is important to examine how they are spread, and thereby, how much of a problem they are. This thesis investigates how the spread of news articles on Twitter can be represented via a tree structure, as well as whether or not the trees have patterns that correlate to attributes such as the source of the shared news article and how many followers the original tweeter has. As part of the study a tool was built in Python 2.7 that, amongst other things, allows tracking and reconstruction of a news article's propagation on Twitter.It could be concluded that most links that are shared on Twitter propagate over a period of a few days and most retweets are made within the first twelve hours. We observe patterns suggesting that having more followers correlates to getting more retweets. Users who have few followers have to rely on their tweets being retweeted in a longer chain of users for it to reach a larger audience. Tweets that have a substantial spread often spread widely, but not especially deep. Finally, our results suggest that both the news site that created the article and the content of the article has an impact on how much it is retweeted.
2

Exploiting Linguistic and Statistical Knowledge in a Text Alignment System

Schrader, Bettina 20 February 2009 (has links)
In machine translation, the alignment of corpora has evolved into a mature research area, aimed at providing training data for statistical or example-based machine translation systems. Moreover, the alignment information can be used for a variety of other purposes, including lexicography and the induction of tools for natural language processing. The alignment techniques used for these purposes fall roughly in two separate classes: sentence alignment approaches that often combine statistical and linguistic information, and word alignment models that are dominated by the statistical machine translation paradigm. Alignment approaches that use linguistic knowledge provided by corpus annotation are rare, as are as non-statistical word alignment strategies. Furthermore, parallel corpora are typically not aligned at all text levels simultaneously. Rather, a corpus is first sentence aligned, and in a subsequent step, the alignment information is refined to go below the sentence level. In this thesis, the distinction between the two alignment classes is withdrawn. Rather, a system is introduced that can simultaneously align at the paragraph, sentence, word, and phrase level. Furthermore, linguistic as well as statistical information can be combined. This combination of alignment cues from different knowledge sources, as well as the combination of the sentence and word alignment tasks, is made possible by the development of a modular alignment platform. Its main features are that it supports different kinds of linguistic corpus annotation, and furthermore aligns a corpus hierarchically, such that sentence and word alignments are cohesive. Alignment cues are not used within a global alignment model. Rather, different sub-models can be implemented and allowed to interact. Most of the alignment modules of the system have been implemented using empirical corpus studies, aimed at showing how the most common types of corpus annotation can be exploited for the alignment task.
3

An Investigation of the ca. 2.7 Ga Late Archean Magmatic Event (LAME) in the Superior Province using 1-D Thermal Modelling

Ahmad, Seema 03 March 2010 (has links)
The Late Archean Magmatic Event (LAME), ca. 2.7 Ga, was the greatest crustal addition event in Earth history. My focus is the Superior Province of Canada, where LAME occurred ca. 2.75 – 2.65 Ga. Mantle plumes impinged on the Abitibi subprovince, where ~ 16 km regional thickness of tonalite-trondhjemite-granodiorite (TTG) melt was produced. Granites (sensu stricto) were the last magmatic phase of LAME, with a Superior-wide regional thickness of ~ 1 – 3 km. Assuming a crustal source for both TTG and granites, I use 1-D thermal models to investigate the origin of TTG in the Abitibi subprovince and that of late granites in the Superior Province. Melting curves appropriate to the source of TTG and granites are used to determine the thickness of melt produced in the models. I show that the incorporation of upward melt transfer into a standard model of lower crustal melting may increase the amount of predicted melt by ~ 1/(1-f), where f denotes the fraction of melt that is on average being extracted from the source rocks. Partitioning of heat producing elements between melt and restite reduces the amount of melt produced, but the effect is secondary compared to the increase in melt production through upward melt transfer. For the Abitibi subprovince, I show that the emplacement of a single plume coupled with the emplacement of a 12-km-thick greenstone cover can generate a maximum of ~ 9-km-thickness of TTG melt. However, the emplacement of a series of plumes, each coupled with the emplacement of a 3-km-thick greenstone cover and a 10-km-thick sill results in ~ 20-km-thickness of TTG melt. My model incorporates delamination of restitic eclogite. Finally, I show that late granites in the Superior Province may have resulted from thickening of a crust that had been “pre-heated” during earlier arc activity and that prolonged granitic magmatism observed in some areas of the Superior Province may be explained by late underthrusting of fertile source rocks into deeper and hotter regions of the crust.
4

An Investigation of the ca. 2.7 Ga Late Archean Magmatic Event (LAME) in the Superior Province using 1-D Thermal Modelling

Ahmad, Seema 03 March 2010 (has links)
The Late Archean Magmatic Event (LAME), ca. 2.7 Ga, was the greatest crustal addition event in Earth history. My focus is the Superior Province of Canada, where LAME occurred ca. 2.75 – 2.65 Ga. Mantle plumes impinged on the Abitibi subprovince, where ~ 16 km regional thickness of tonalite-trondhjemite-granodiorite (TTG) melt was produced. Granites (sensu stricto) were the last magmatic phase of LAME, with a Superior-wide regional thickness of ~ 1 – 3 km. Assuming a crustal source for both TTG and granites, I use 1-D thermal models to investigate the origin of TTG in the Abitibi subprovince and that of late granites in the Superior Province. Melting curves appropriate to the source of TTG and granites are used to determine the thickness of melt produced in the models. I show that the incorporation of upward melt transfer into a standard model of lower crustal melting may increase the amount of predicted melt by ~ 1/(1-f), where f denotes the fraction of melt that is on average being extracted from the source rocks. Partitioning of heat producing elements between melt and restite reduces the amount of melt produced, but the effect is secondary compared to the increase in melt production through upward melt transfer. For the Abitibi subprovince, I show that the emplacement of a single plume coupled with the emplacement of a 12-km-thick greenstone cover can generate a maximum of ~ 9-km-thickness of TTG melt. However, the emplacement of a series of plumes, each coupled with the emplacement of a 3-km-thick greenstone cover and a 10-km-thick sill results in ~ 20-km-thickness of TTG melt. My model incorporates delamination of restitic eclogite. Finally, I show that late granites in the Superior Province may have resulted from thickening of a crust that had been “pre-heated” during earlier arc activity and that prolonged granitic magmatism observed in some areas of the Superior Province may be explained by late underthrusting of fertile source rocks into deeper and hotter regions of the crust.
5

Systém pro sledování trajektorie objektů pohybujících se v prostoru / System for Trajectory Tracking of Objects Moving in Space

Jakubíček, Patrik January 2016 (has links)
This thesis deals with a system for tracking the trajectory of the moving object. Further, also for obtaining additional motion data and other information. Thesis focuses on flying objects. There are described all system components and way of their communication. Next, the progress of the expansion unit for measuring by the BeagleBone Black platform. Also there is described testing that took place during aerobatic gliders races, including the demonstrations of recording data and their processing.
6

Object Warehouse - Konzeption der Basis objektorientierter Management Support Systems am Beispiel von Smalltalk und dem ERP Baan

Maur, Eitel von 18 May 2001 (has links)
Die Arbeit untersucht die Realisierungsmöglichkeiten der Potenziale des objektorientierten Paradigmas im Bereich der Management Support Systems (MSS). Die Untersuchung konzentriert sich dabei auf die grundlegende Datenhaltungskomponente, das Data Warehouse (DWH) respektive Object Warehouse. Dazu wird im ersten Teil zunächst nach einer ausführlichen Analyse der Begriffslandschaft im Bereich der Management Support Systems und einer geeigneten Neudefinition und Einordnung des Data Warehouse auf den Entwicklungspfad des Data Warehouse eingegangen, bei welchem insbesondere die Anforderungen und Zielsetzungen des Data-Warehouse-Konzeptes herausgearbeitet werden. Darauf aufbauend wird ein generelles, systemunabhängiges Data-Warehouse-Konzept entwickelt und gegenüber den in der Literatur und Praxis vorherrschenden, konventionellen Konzepten bewertet. Basierend auf einer umfassenden Klassifizierung und Analyse des objektorientierten Paradigmas und seiner MSS- und DWH-spezifischen Verbesserungspotenziale erfolgt anschließend die Konzeption für ein Object Warehouse. Angesichts der erheblichen Anzahl bezüglich Konzepten und Zielsetzungen sehr unterschiedlicher Objekt-Paradigmata, muss die gleichwohl notwendige Paradigmen-Diskussion und Integration teilweise beschränkt auf den Teilaspekt der Objectbase Management Systems (OBMS) erfolgen, speziell auf solche, die die geforderten semantischen Modellierungsmöglichkeiten des Objekt-Paradigmas für den Reconciled Object Layer des Data Warehouse unterstützen. Im zweiten Teil der Arbeit werden die in konkreten Projekten gewonnenen Erkenntnisse bezüglich der Umsetzung des Object-Warehouse-Konzeptes in der Praxis vorgestellt und einer kritischen Würdigung unterzogen. Dabei werden erhebliche Diskrepanzen bezüglich der Umsetzung methodischer Konzeptionen in realen Software-Werkzeugen expliziert, was eine umfassende Umsetzung des Object-Warehouse-Konzeptes zur Zeit noch erheblich einschränkt.
7

Model-Based Exploration of Parallelism in Context of Automotive Multi-Processor Systems

Höttger, Robert Martin 15 July 2021 (has links)
This dissertation entitled ’Model-Based Exploration of Parallelism in the Context of Automotive Multi-Core Systems’ deals with the analytical investigation of different temporal relationships for automotive multi-processor systems subject to critical, embedded, real-time, distributed, and heterogeneous domain requirements. Vehicle innovation increasingly demands high-performance platforms in terms of, e.g., highly assisted or autonomous driving such that established software development processes must be examined, revised, and advanced. The goal is not to develop application software itself, but instead to improve the model-based development process, subject to numerous constraints and requirements. Model-based software development is, for example, an established process that allows systems to be analyzed and simulated in an abstracted, standardized, modular, isolated, or integrated manner. The verification of real-time behavior taking into account various constraints and modern architectures, which include graphics and heterogeneous processors as well as dedicated hardware accelerators, is one of many challenges in the real-time and automotive community. The software distribution across hardware entities and the identification of software that can be executed in parallel are crucial in the development process. Since these processes usually optimize one or more properties, they belong to the category of problems that can only be solved in polynomial time using non-deterministic methods and thus make use of (meta) heuristics for being solved. Such (meta) heuristics require sophisticated implementation and configuration, due to the properties to be optimized are usually subject to many different analyses. With the results of this dissertation, various development processes can be adjusted to modern architectures by using new and extended processes that enable future and computationally intensive vehicle applications on the one hand and improve existing processes in terms of efficiency and effectiveness on the other hand. These processes include runnable partitioning, task mapping, data allocation, and timing verification, which are addressed with the help of constraint programming, genetic algorithms, and heuristics.

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