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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.
41

Daily pattern recognition of dynamic origin-destination matrices using clustering and kernel principal component analysis / Daglig mönsterigenkänning av dynamiska Origin-Destination-matriser med hjälp av clustering och kernel principal component analysis

Dong, Zhiwu January 2021 (has links)
Origin-Destination (OD) matrix plays an important role in traffic management and urban planning. However, the OD estimation demands large data collection which has been done in past mostly by surveys with numerous limitations. With the development of communication technology and artificial intelligence technology, the transportation industry experiences new opportunities and challenges. Sensors bring big data characterized by 4V (Volume, Variety, Velocity, Value) to the transportation domain. This allows traffic practitioners to receive data covering large-scale areas and long time periods, even several years of data. At the same time, the introduction of artificial intelligence technology provides new opportunities and challenges in processing massive data. Advances from computer science have also brought revolutionary advancements in the field of transportation. All these new advances and technologies enable large data collection that can be used for extracting and estimating dynamic OD matrices for small time intervals and long time periods.Using Stockholm as the focus of the case study, this thesis estimates dynamic OD matrices covering data collected from the tolls located around Stockholm municipality. These dynamic OD matrices are used to analyze the day-to-day characteristics of the traffic flow that goes through Stockholm. In other words, the typical day-types of traffic through the city center are identified and studied in this work. This study analyzes the data collected by 58 sensors around Stockholm containing nearly 100 million vehicle observations (12GB).Furthermore, we consider and study the effects of dimensionality reduction on the revealing of most common day-types by clustering. The considered dimensionality reduction techniques are Principal Component Analysis (PCA) and its variant Kernel PCA (KPCA). The results reveal that dimensionality reduction significantly drops computational costs while resulting in reasonable day-types. Day-type clusters reveal expected as unexpected patterns and thus could have potential in traffic management, urban planning, and designing the strategy for congestion tax. / Origin-Destination (OD) -matrisen spelar en viktig roll i trafikledning och stadsplanering. Emellertid kräver OD-uppskattningen stor datainsamling, vilket har gjorts tidigare mest genom enkäter med många begränsningar. Med utvecklingen av kommunikationsteknik och artificiell intelligens upplever transportindustrin nya möjligheter och utmaningar. Sensorer ger stor data som kännetecknas av 4V (på engelska, volym, variation, hastighet, värde) till transportdomänen. Detta gör det möjligt för trafikutövare att ta emot data som täcker storskaliga områden och långa tidsperioder, till och med flera års data. Samtidigt ger introduktionen av artificiell intelligens teknik nya möjligheter och utmaningar i behandlingen av massiva data. Datavetenskapens framsteg har också lett till revolutionära framsteg inom transportområdet. Alla dessa nya framsteg och tekniker möjliggör stor datainsamling som kan användas för att extrahera och uppskatta dynamiska OD-matriser under små tidsintervall och långa tidsperioder.Genom att använda Stockholm som fokus för fallstudien uppskattar denna avhandling dynamiska OD-matriser som täcker data som samlats in från vägtullarna runt Stockholms kommun. Dessa dynamiska OD-matriser används för att analysera de dagliga egenskaperna hos trafikflödet i Stockholm genom stadens centrum. Med andra ord känns igen och studeras de typiska dagtyperna av trafik genom stadens centrum i detta arbete. Denna studie analyserar data som samlats in av 58 sensorer runt Stockholm som innehåller nästan 100 miljoner fordonsobservationer (12 GB)Dessutom överväger och studerar vi effekterna av dimensioneringsreduktion på avslöjandet av de vanligaste dagtyperna genom kluster. De betraktade dimensioneringsreduktionsteknikerna är Principal Component Analysis (PCA) och dess variant Kernel PCA (KPCA). Resultaten avslöjar att dimensioneringsreduktion avsevärt minskar beräkningskostnaderna, samtidigt som det ger rimliga dagtyper. Dagstyp kluster avslöjar förväntade som oväntade mönster och därmed kan ha potential i trafikledning, stadsplanering och utformning av strategin för trängselskatt.
42

Adhesion of the rapeseed pathogen Verticillium longisporum to its host Brassica napus: Uncovering adhesion genes and the evolutionary origin of the fungus / Die Adhäsion der Raps Erreger Verticillium longisporum seinen Wirt Brassica napus: Aufdeckung Adhäsion Genen und der evolutionären Ursprung des Pilzes

Tran, Van Tuan 02 May 2011 (has links)
No description available.
43

Origin and evolution of ureilite vein metal - Fe, Ni, Co and Ni-isotope systematics of ureilite vein metal and ureilite silicates

Gabriel, Aron David 30 October 2009 (has links)
No description available.
44

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

Tanriverdi, Vedat 28 June 2011 (has links)
No description available.
45

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

Kutzner, Carsten 27 March 2003 (has links)
No description available.
46

The Planck Constant and the Origin of Mass due to a Higher Order Casimir Effect

Baumgärtel, C., Tajmar, Martin 10 July 2018 (has links) (PDF)
The Planck constant is one of the most important constants in nature, as it describes the world governed by quantum mechanics. However, it cannot be derived from other natural constants. We present a model from which it is possible to derive this constant without any free parameters. This is done utilizing the force between two oscillating electric dipoles described by an extension of Weber electrodynamics, based on a gravitational model by Assis. This leads not only to gravitational forces between the particles but also to a newly found Casimir-type attraction. We can use these forces to calculate the maximum point mass of this model which is equal to the Planck mass and derive the quantum of action. The result hints to a connection of quantum effects like the Casimir force and the Planck constant with gravitational ones and the origin of mass itself.
47

Ursprungsmächte bei Cheikh Anta Diop und Nietzsche

Boa, Thiémélé Léon January 2001 (has links)
Zwischen Nietzsche und Cheikh Anta Diop gibt es wenige Verbindungen. Nietzsche gilt inzwischen unbezweifelbar als Philosoph, während bei Cheikh Anta Diop diese Anerkennung noch aussteht. Der eine ist ein in Deutschland geborener Europäer (1844-1900), der andere ein im Senegal geborener Afrikaner (1923-1986). Beide waren der Antike zugewandt und fanden darin Kraft für ihre Hoffnungen. Der eine stützte sich auf das antike Griechenland und der andere auf das antike Ägypten, beide forderten damit die Wissenschaftlergemeinschaft ihrer Zeit heraus und erschütterten die Wissensordnung ihrer Zeit. Absichtlich provokativ haben sie auf eine unsichere Zukunft gesetzt. Beide haben sie Grenzen des Wissens und Grenzen der Politik überschritten. Im folgenden sollen die Ähnlichkeiten der unzeitgemäßen Denkformen beider Denker im Vordergrund stehen. Für Cheikh Anta Diop und Nietzsche steht fest, dass wir unserer Existenz durch den historischen Sinn einen Wert geben. Der eine lädt uns ein, in der Erforschung der pharaonischen Ursprünge die Zielrichtung einer Konstruktion der afrikanischen Zukunft zu finden, was der Haltung von Nietzsche ähnelt, der das dekadente Europa seiner Zeit dazu aufrief, sich aus der griechischen Seele als seinem eigentlichen Sein zu erneuern. Beide Denker haben die Macht der Erinnerung thematisiert, Ursprünge und große Anfänge herausgehoben.
48

The Planck Constant and the Origin of Mass due to a Higher Order Casimir Effect

Baumgärtel, C., Tajmar, Martin 10 July 2018 (has links)
The Planck constant is one of the most important constants in nature, as it describes the world governed by quantum mechanics. However, it cannot be derived from other natural constants. We present a model from which it is possible to derive this constant without any free parameters. This is done utilizing the force between two oscillating electric dipoles described by an extension of Weber electrodynamics, based on a gravitational model by Assis. This leads not only to gravitational forces between the particles but also to a newly found Casimir-type attraction. We can use these forces to calculate the maximum point mass of this model which is equal to the Planck mass and derive the quantum of action. The result hints to a connection of quantum effects like the Casimir force and the Planck constant with gravitational ones and the origin of mass itself.
49

Barnets rätt till sina föräldrar : En kritisk rättsdogmatisk analys av rättsligt föräldraskap i relation till Barnkonventionen / The child’s right to his/her parents : A legal dogmatic analysis of legal parenthood in relation to the convention on the rights of the child

Jeppson, Veronica January 2019 (has links)
The Convention on the rights of the child (CRC) stipulates a set of rights for all children and declares that all national legislation should be in compliance with the convention. The CRC states that the best interests of the child shall be of primary consideration in all actions concerning children; that every child has the right to protection of their family relations as well as the right to know about its parents. The purpose of this study is to investigate how well does the Swedish regulation of establishing legal parenthood comply with the child’s family oriented rights stipulated by the CRC. The study uses a critical legal dogmatic method and is analysed from a theory of the best interests of the child principle. The result shows that the Swedish law strongly protects the child’s right to know about his/her genetic origin. However, the findings illustrate that the mentioned right is often seen as synonymous for what is best for the child, and therefore leaves no space for questioning other aspects that may affect the child’s well-being. Furthermore the results demonstrate that the Swedish family law mainly protects hetero normative families where none of the parents has changed their legal gender. The further away from this norm that the child’s family is, the more complicated it is to establish legal parenthood and therefor harder to protect the child’s right to its family relations. The paper argues that the Swedish family law hence leaves little space for what could be seen as the best interest of a specific child in a specific context, and by doing so diverges from the CRC which advocates contextually when analysing what is best for the child. The paper concludes that a more flexible law where the best interests of the child can be taken into account in greater extent could secure the rights of the child more effectively.
50

Analyse epileptischer Aktivität anhand intrinsischer optischer Signale und elektrophysiologischer Methoden in vitro nach Status epilepticus in vivo

Elsner, Mark Michael 28 October 2004 (has links)
Eine wichtige Folge des Status epilepticus ist die Entwicklung einer chronischen Epilepsie. Die genauen Mechanismen und die Kinetik der Epileptogenese sind weitestgehend unklar. Ziel der vorliegenden Arbeit war ein besseres Verständnis des Prozesses durch die In-vitro-Analyse von Lokalisation und Kinetik funktioneller Folgen des Status epilepticus in vivo. In kombinierten Hippokampus-entorhinaler Kortex Hirnschnittpräparaten von Wistar-Ratten nach elektrisch induziertem selbsterhaltendem Status epilepticus (self-sustaining status epilepticus, SSSE) wurden im Niedrig-Magnesium-Modell anfallsartige Ereignisse (AE) ausgelöst und untersucht. Die In-vitro-Analyse der AE wurde eine, vier und acht Wochen nach SSSE durchgeführt. Um das räumliche Verhalten der epileptischen Aktivität beurteilen zu können, wurde die Messung des extrazellulären Feldpotenzials mit der Analyse intrinsischer optischer Signale kombiniert. Im Verlauf nach SSSE kam es zu einer Latenzverkürzung bis zum Auftreten epileptischer Aktivität und zu einer Zunahme der AE-Frequenz. Vier und acht Wochen nach SSSE stieg der Anteil der AE mit großflächigem Ursprung signifikant an. Im Verlauf nach SSSE wurden außerdem zunehmend diskontinuierliche Ausbreitungsmuster der Anfallsaktivität beobachtet. Acht Wochen nach SSSE zeigten 50% der Präparate zudem eine zeitlich und räumlich von den AE unabhängige, hochfrequente Aktivität im Gyrus dentatus. Zusammenfassend wurden eine Latenzverkürzung und eine Zunahme der AE-Frequenz als Hinweise für eine gesteigerte Exzitabilität des Hirngewebes nach SSSE gesehen. Neben dem großflächigen Ursprung deutet auch die Zunahme diskontinuierlicher Ausbreitungsmuster auf eine gesteigerte Synchronizität des neuronalen Netzwerkes nach SSSE hin. Die autonome Aktivität im Gyrus dentatus spricht dafür, dass die in vorangegangenen Studien beschriebenen strukturellen Änderungen in dieser Region mit einer veränderten Funktionalität einhergehen. / The development of chronic epilepsy is a serious consequence of Status epilepticus. Little is known about the mechanisms and kinetic of the epileptogenic process. The aim of this md-thesis was the analysis of localisation and kinetic of functional deficits in vitro after Status epilepticus in vivo. Using the Low-Magnesium-Model, seizure-like events (SLE) were induced in combined hippocampal-entorhinal cortex slices of wistar rats after electrically induced self-sustaining Status epilepticus (SSSE). One, four and eight weeks after SSSE the in-vitro-analysis of SLE was performed. In order to determine onset and spread-pattern of epileptic activity, the measurement of the extracellular field-potential was combined with the imaging of intrinsic optical signals (IOS). In the time course after SSSE there was a reduction of the latency to onset of seizure activity and an increase of the SLE-frequency. Four and eight weeks after SSSE a significant increase of SLE with regional onset was found. In Addition, there was an increase of non-contiguous propagation of seizure activity. Eight weeks after SSSE 50% of the brain-slices showed autonomous high-frequent activity in the dentate gyrus. In conclusion a reduction of the latency to onset of seizure activity and an increase of the SLE-frequency were found. These changes are indicators of increased excitability after SSSE. Other than the regional onset, the non-contiguous spread-pattern also indicates increased synchronicity of the neuronal network after SSSE. The autonomous activity in the dentate Gyrus shows, that the previously described structural changes in this region lead to functional deficits.

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