• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 2
  • 1
  • Tagged with
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

DESIGN, DEVELOPMENT AND EVALUATION OF AN ADAPTIVE AND STANDARDIZED RTP/RTCP-BASED IDMS SOLUTION

Montagut Climent, Mario Alberto 31 March 2015 (has links)
Nowadays, we are witnessing a transition from physical togetherness towards networked togetherness around media content. Novel forms of shared media experiences are gaining momentum, allowing geographically distributed users to concurrently consume the same media content while socially interacting (e.g., via text, audio or video chat). Relevant use cases are, for example, Social TV, networked games and multi-party conferencing. However, realizing enjoyable shared media services faces many challenges. In particular, a key technological enabler is the concurrent synchronization of the media playout across multiple locations, which is known as Inter-Destination Multimedia Synchronization (IDMS). This PhD thesis presents an inter-operable, adaptive and accurate IDMS solution, based on extending the capabilities of RTP/RTCP standard protocols (RFC 3550). Concretely, two new RTCP messages for IDMS have been defined to carry out the necessary information to achieve IDMS. Such RTCP extensions have been standardized within the IETF, in RFC 7272. In addition, novel standard-compliant Early Event-Driven (EED) RTCP feedback reporting mechanisms have been also designed to enhance the performance in terms of interactivity, flexibility, dynamism and accuracy when performing IDMS. The designed IDMS solution makes use of globally synchronized clocks (e.g., using NTP) and can adopt different (centralized and distributed) architectural schemes to exchange the RTCP messages for IDMS. This allows efficiently providing IDMS in a variety of networked scenarios and applications, with different requirements (e.g., interactivity, scalability, robustness…) and available resources (e.g., bandwidth, latency, multicast support…). Likewise, various monitoring and control algorithms, such as dynamic strategies for selecting the reference timing to synchronize with, and fault tolerance mechanisms, have been added. Moreover, the proposed IDMS solution includes a novel Adaptive Media Playout (AMP) technique, which aims to smoothly adjust the media playout rate, within perceptually tolerable ranges, every time an asynchrony threshold is exceeded. Prototypes of the IDMS solution have been implemented in both a simulation and in real media framework. The evaluation tests prove the consistent behavior and the satisfactory performance of each one of the designed components (e.g.,protocols, architectural schemes, master selection policies, adjustment techniques…). Likewise, comparison results between the different developed alternatives for such components are also provided. In general, the obtained results demonstrate the ability of this RTP/RTCP-based IDMS solution to concurrently and independently maintain an overall synchronization status (within allowable limits) in different logical groups of users, while avoiding annoying playout discontinuities and hardly increasing the computation and traffic load. / Montagut Climent, MA. (2015). DESIGN, DEVELOPMENT AND EVALUATION OF AN ADAPTIVE AND STANDARDIZED RTP/RTCP-BASED IDMS SOLUTION [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48549 / TESIS / Premios Extraordinarios de tesis doctorales
2

Preparação e caracterização de um material de referência de peixe / Preparation and characterization of the fish reference material

Ulrich, João Cristiano 01 March 2011 (has links)
Os materiais de referência certificados (MRCs) desempenham importante papel na obtenção de resultados de medições rastreáveis ao Sistema Internacional de Unidades (SI), por meio de uma cadeia contínua de comparações. Dessa forma, a demanda por novos materiais de referência certificados (MRC) aumenta a cada dia em todas as áreas do conhecimento. A disponibilidade de materiais de referência, principalmente no Brasil, ainda é incipiente, face a demanda que excede em muito a variedade disponível desses materiais. Entre as diversas áreas carentes de materiais de referência, destaca-se a área de alimentos pela importância desses produtos na balança comercial do país. A certificação de produtos alimentícios, destinados tanto para exportação como para o consumo interno, requer metodologias de análise que ofereçam resultados precisos e exatos a fim de assegurar a qualidade do produto. Este trabalho descreve a produção e certificação de um material de referência na matriz peixe em mercúrio e metilmercúrio. O estudo reúne desde a etapa de seleção do material, preparação, desenvolvimento dos estudos de homogeneidade e estabilidade e a caracterização. A certificação foi realizada por meio de medições utilizando duas técnicas analíticas, a Espectrofotometria de Absorção Atômica (AAS) com sistema de injeção em fluxo e geração de vapor frio (FIA-CV-AAS) e a Diluição Isotópica aplicada a Espectrometria de Massas (IDMS), sendo este um método primário. Neste trabalho as normas da série ISO 30 (ABNT 3034) e ISO Guide 35 foram utilizadas como base para a preparação e caracterização do material. Para o cálculo de incertezas foi utilizado o GUM e o guia Eurachem. Como resultado, foi produzido e certificado um lote do material em relação ao teor de mercúrio (Hg = 0,271±0,057 μg g-1) e metilmercúrio (MeHg = 0,245±0,038 μg g-1), além de valores informativos de chumbo e arsênio. / The certified reference materials (CRMs) play an important role in obtaining measurement results traceable to the International System of Units, through an unbroken chain of comparisons. Thus, the demand for new certified reference materials (CRMs) increases every day in all areas of knowledge. The availability of reference materials, mainly in Brazil is still incipient, given that the demand far exceeds the available variety of these materials. The amount of certified reference materials available in the country is insufficient to meet the need of the scientific community and demands for development of new methodologies. Among the many areas in need of reference materials, we highlight the importance for the food trade balance for these products within the country. The certification of food products, intended both for export and for domestic consumption, requires analysis methods that provide precise and accurate results to ensure product quality. This paper describes the preparation and certification of a reference material in the fish matrix in mercury and methylmercury. The study brings together since the stage of material selection, preparation, development of homogeneity and stability studies and characterization. The certification was performed by means of measurements using two analytical techniques, flow injection analysis - cold vapor atomic absorption spectrometry (FIA-CV-AAS) and isotope dilution applied to mass spectrometry (IDMS), which is a primary method. In this work the standards of the ISO 30 (ABNT 30-34) and ISO Guide 35 was used as the basis for the preparation and characterization of the material. For the calculation of uncertainties was used the GUM and Eurachem guide. As a result, was produced and certified a lot of material in relation to the concentration of mercury (Hg = 0.271 ± 0.057 mg g-1) and methylmercury (MeHg = 0.245 ± 0.038 mg g-1), and informational values of lead and arsenic .
3

Preparação e caracterização de um material de referência de peixe / Preparation and characterization of the fish reference material

João Cristiano Ulrich 01 March 2011 (has links)
Os materiais de referência certificados (MRCs) desempenham importante papel na obtenção de resultados de medições rastreáveis ao Sistema Internacional de Unidades (SI), por meio de uma cadeia contínua de comparações. Dessa forma, a demanda por novos materiais de referência certificados (MRC) aumenta a cada dia em todas as áreas do conhecimento. A disponibilidade de materiais de referência, principalmente no Brasil, ainda é incipiente, face a demanda que excede em muito a variedade disponível desses materiais. Entre as diversas áreas carentes de materiais de referência, destaca-se a área de alimentos pela importância desses produtos na balança comercial do país. A certificação de produtos alimentícios, destinados tanto para exportação como para o consumo interno, requer metodologias de análise que ofereçam resultados precisos e exatos a fim de assegurar a qualidade do produto. Este trabalho descreve a produção e certificação de um material de referência na matriz peixe em mercúrio e metilmercúrio. O estudo reúne desde a etapa de seleção do material, preparação, desenvolvimento dos estudos de homogeneidade e estabilidade e a caracterização. A certificação foi realizada por meio de medições utilizando duas técnicas analíticas, a Espectrofotometria de Absorção Atômica (AAS) com sistema de injeção em fluxo e geração de vapor frio (FIA-CV-AAS) e a Diluição Isotópica aplicada a Espectrometria de Massas (IDMS), sendo este um método primário. Neste trabalho as normas da série ISO 30 (ABNT 3034) e ISO Guide 35 foram utilizadas como base para a preparação e caracterização do material. Para o cálculo de incertezas foi utilizado o GUM e o guia Eurachem. Como resultado, foi produzido e certificado um lote do material em relação ao teor de mercúrio (Hg = 0,271±0,057 μg g-1) e metilmercúrio (MeHg = 0,245±0,038 μg g-1), além de valores informativos de chumbo e arsênio. / The certified reference materials (CRMs) play an important role in obtaining measurement results traceable to the International System of Units, through an unbroken chain of comparisons. Thus, the demand for new certified reference materials (CRMs) increases every day in all areas of knowledge. The availability of reference materials, mainly in Brazil is still incipient, given that the demand far exceeds the available variety of these materials. The amount of certified reference materials available in the country is insufficient to meet the need of the scientific community and demands for development of new methodologies. Among the many areas in need of reference materials, we highlight the importance for the food trade balance for these products within the country. The certification of food products, intended both for export and for domestic consumption, requires analysis methods that provide precise and accurate results to ensure product quality. This paper describes the preparation and certification of a reference material in the fish matrix in mercury and methylmercury. The study brings together since the stage of material selection, preparation, development of homogeneity and stability studies and characterization. The certification was performed by means of measurements using two analytical techniques, flow injection analysis - cold vapor atomic absorption spectrometry (FIA-CV-AAS) and isotope dilution applied to mass spectrometry (IDMS), which is a primary method. In this work the standards of the ISO 30 (ABNT 30-34) and ISO Guide 35 was used as the basis for the preparation and characterization of the material. For the calculation of uncertainties was used the GUM and Eurachem guide. As a result, was produced and certified a lot of material in relation to the concentration of mercury (Hg = 0.271 ± 0.057 mg g-1) and methylmercury (MeHg = 0.245 ± 0.038 mg g-1), and informational values of lead and arsenic .
4

Novel Solid-Phase Extraction Techniques for Biological and Environmental Analysis Using Isotope Dilution Mass Spectrometry

Boggess, Andrew 18 May 2016 (has links)
Awareness and study of the ways in which the environment can interact with the personal genetics and epigenetics of an individual has grown substantially in recent years, resulting in the field of Exposomics. In an era of increasingly personalized medicine, novel techniques are necessary to ensure the accurate and sensitivity measurement of clinically and environmentally relevant molecules in biological and environmental samples. Addressing existing shortcomings cited in literature, methods were developed and optimized for the extraction, separation, mass analysis, and quantification of a suite of environmental organic pollutants in both biological and environmental samples, with the primary objective of improving accuracy, increasing sensitivity, and reducing sample and reagent consumption. The secondary objective of this research was the production of validated methods capable of inter-laboratory method transfer with minimal training required in the receiving laboratory. Two novel methods have been developed, optimized, validated, and applied to collaborative environmental research. These novel methods represented a demonstrative improvement upon existing methods in both analytical quality and capability for inter-laboratory method transfer. Both developed methods were utilized in two collaborative clinical research studies investigating the impact of environmentally-sources agents on children diagnosed with autism spectrum disorders (ASD). The high-quality data obtained in these studies yielded results that may have provided valuable insight into the development and maintenance of autism spectrum disorders. These novel methods allowed for the discovery of a first-of-its-kind variable in the children with ASD, compared with controls. This variable was statistically predictive for the probability of an individual being diagnosed with the most behaviorally severe autism disorder, with a statistically significant overall model fit. This novel analytical method was then expanded in breadth through application to industrial and municipal wastewater to aid in updating EPA Method 625 for wastewater analysis. Applying this novel method to wastewater produced data of higher analytical quality, in both accuracy and precision, compared with all other collaborative laboratories. The methods developed in this work for the quantification of organic molecules implicated in environmental human health in biological and environmental samples have significantly improved analytically upon existing methods and have yielded clinically relevant findings in collaborative clinical research studies. / Bayer School of Natural and Environmental Sciences; / Chemistry and Biochemistry / PhD; / Dissertation;
5

Development and Application of IDMS Based Procedure for total Sulphur in Copper Metals and Its Alloys

Phukphatthanachai, Pranee 05 April 2019 (has links)
Bei der Schwefelquantifizierung in Kupfer und anderen reinen Metallen zeigte sich in der Vergangenheit eine mangelnde SI-Rückführung und zusätzlich inkonsistente Ergebnisse, wenn verschiedene Methoden verglichen wurden. Um diesen Mangel zu beheben ist ein Referenzverfahren erforderlich, welches SI-rückführbare Werte mit einem zuverlässigen Unsicherheitsbudget ermöglicht. In dieser Studie wurde ein entsprechendes Referenzverfahren zur Quantifizierung von Gesamtschwefel in Kupfer basierend auf der induktiv gekoppelten Plasma-Massenspektrometrie und der Isotopenverdünnungsanalyse (ICP-IDMS) entwickelt. Um diese Probleme zu lösen wurde mit Hilfe der Ionenaustauschchromatographie ein Schwefel-Matrix-Trennverfahren entwickelt. Dieses Trennverfahren wurde mit ICP-IDMS kombiniert, um Schwierigkeiten mit der Kalibrierung zu lösen und fehlende metrologische Konzepte einzuführen. So wurden die in diesem Projekt erzielten IDMS-Messwerte für die Kalibrierung von GDMS und LA-ICP-MS verwendet, beides Verfahren die im industriellen Einsatz üblich sind. Dadurch konnten mit beiden Routineverfahren zuverlässige Ergebnisse erzeilt warden, die zudem auf SI rückführbar sind. Darüber hinaus wurde ein auf der LA-ICP-IDMS basierendes Verfahren entwickelt, um den Probenvorbereitungsschritt von ICP-IDMS mit Schwefel-Matrix-Trennung zu reduzieren. Die Vorteile dieser Methode sind ein geringerer Arbeits- und Zeitaufwand, die SI- Rückführung der Messergebnisse und eine für LA-ICP-MS vergleichsweise hohe Genauigkeit. Die Schlüsselrolle hierbei spielte der innovative Einsatz von Polyethylenfritten als Trägermaterial der aufgelösten Probe. Dadurch war die Quantifizierung von Schwefel in Kupferproben mittels LA-ICP-IDMS möglich. Die wesentlichen Parameter wie Absorptionseffizienz der Fritten und Matrixeffekt wurden untersucht. Das entwickelte Verfahren konnte mit Hilfe der ICP-IDMS vollständig validiert werden. / Sulphur quantification in copper and other pure metals in the past revealed a lack of SI-traceability and also showed inconsistent results, when different methods are compared. Therefore, a reference procedure is required to enable SI-traceable measurement results accompanied by a sound uncertainty budget. In this study, such a procedure was developed for the quantification of total sulphur in copper using inductively coupled plasma-isotope dilution mass spectrometry (ICP-IDMS). For solving these problems ion exchange chromatography was applied, and a sulphur-matrix separation procedure was developed. This procedure was combined with ICP-IDMS to solve difficulties with the calibration and to realize metrological concepts. An application of the IDMS procedure was realized by using the measurement results of specific copper samples values for calibrating glow discharge mass spectrometry (GDMS) and laser ablation ICP-MS (LA-ICP-MS). Both techniques are considered routine techniques. Thus, they could provide reliable results which are traceable to the SI. Additionally, a procedure based on LA-ICP-IDMS was developed to significantly reduce the sample preparation step of ICP-IDMS with sulphur-matrix separation. This procedure is less laborious and the measurement results are still SI traceable and offer a comparatively high accuracy for LA-ICP-MS. Key for this development was the innovative application of polyethylene frits as support material for the dissolved sample. Thus, the quantification of sulphur in copper samples by LA-ICP-IDMS could be realized. The essential parameters are investigated such as the absorption efficiency of the frit and matrix effects. The developed procedure was fully validated by means of the ICP-IDMS results.
6

Especificación, implementación y evaluación de soluciones de sincronización multimedia híbrida (broadcast/broadband) e inter-destinatario para posibilitar nuevas experiencias televisivas enriquecidas, personalizadas, inmersivas y compartidas.

Marfil Reguero, Daniel 05 September 2022 (has links)
[ES] Actualmente, existe una gran variedad de tecnologías de distribución de contenidos multimedia, de dispositivos de consumo, así como de tipos de contenidos. En cuanto a tecnologías de distribución, dichos contenidos se pueden enviar bien a través de redes broadcast, como las redes DVB, o bien a través de redes broadband, como las redes IP (por ejemplo, a través de Internet). La coordinación y convergencia entre los dos tipos de tecnologías para distribuir contenidos relacionados ofrece un gran potencial a los proveedores de contenidos, así como grandes beneficios a los consumidores (una prueba de ello es el estándar Hybrid Broadcast Broadband TV o HbbTV). Sin embargo, la recepción de contenidos relacionados procedentes de diferentes redes híbridas (broadcast/broadband) conlleva una variabilidad de retardos significativa, por lo que se deben superar una serie de retos importantes, como, por ejemplo, la necesidad de mecanismos que garanticen un consumo sincronizado de dichos contenidos, bien en un mismo dispositivo o bien en distintos dispositivos (locales o remotos). Se han especificado, implementado y evaluado soluciones de sincronización de los procesos de reproducción de contenidos híbridos (prevenientes de redes broadcast y/o broadband) tanto en entornos multidispositivo, entre dispositivos locales (Inter-Device Synchronization o IDES), como en entornos multiusuario, entre destinatarios distribuidos en red (Inter-Destination Media Synchronization o IDMS), incluyendo la sincronización de efectos multisensoriales. Se ha diseñado e implementado una plataforma extremo-a-extremo para la generación, distribución (adaptativa) y consumo de contenidos híbridos relacionados, tanto en un mismo dispositivo como en múltiples dispositivos locales (por ejemplo, escenario multipantalla) o remotos (por ejemplo, TV Social). Se han generado y preparado contenidos multimedia tradicionales (2D) y omnidireccionales (360), enriquecidos con efectos multisensoriales que mejoran el grado de realismo y la inmersividad de los usuarios. La plataforma es compatible con el estándar HbbTV y, además, incluye soluciones eficientes para aspectos clave que no están especificados en dicho estándar, pero que son necesarios para la implementación satisfactoria de servicios de TV híbridos y multidispositivo en la misma, como, por ejemplo: la necesidad de un buffer para el contenido broadcast (existente y opcional hasta la especificación HbbTV 2.0.2); mecanismos de señalización, asociación y descripción de contenido disponible y relacionado con el contenido principal; mecanismos de coordinación e interacción entre los dispositivos de consumo; o soluciones de sincronización para alinear en el tiempo el consumo de contenidos de forma satisfactoria. Los resultados obtenidos en la evaluación realizada muestran que el nivel de sincronización adquirido entre los procesos de reproducción de los diversos tipos de contenido disponibles a través de distintas tecnologías de transmisión alcanza unos valores suficientes para proporcionar al usuario un consumo con un nivel de asincronías imperceptible. Dicha precisión alcanzada ha resultado en una QoE para el consumidor muy satisfactoria, ofreciéndole al mismo un completo ecosistema de consumo de contenidos que incluye tanto contenido multimedia tradicional, como contenido omnidireccional y mulsemedia. / [CA] Actualment, hi ha una gran varietat de tecnologies de distribució de contingut multimèdia, dispositius de consum, així com tipus de contingut. Pel que fa a les tecnologies de distribució, aquest contingut es pot lliurar a través de xarxes de difusió, com ara xarxes DVB, o a través de xarxes de banda ampla, com les xarxes IP (per exemple, a través d'Internet). La coordinació i convergència entre els dos tipus de tecnologies per distribuir continguts relacionats ofereix un gran potencial als proveïdors de continguts, així com grans beneficis per als consumidors (una prova d'això és l'estàndard Hybrid Broadcast Broadband TV o HbbTV). Tanmateix, la recepció de continguts relacionats des de diferents xarxes híbrides (emissió/banda ampla) comporta una important variabilitat de retard, per la qual cosa s'han de superar una sèrie de reptes importants, com la necessitat de mecanismes que garanteixin el consum sincronitzat d'aquests continguts, ja siga en el mateix dispositiu. o en diferents dispositius (locals o remots). S'han especificat, implementat i evaluat solucions de sincronització per a processos de reproducció de continguts híbrids (xarxes de broadcast i/o de banda ampla) tant en entorns multidispositiu, entre dispositius locals (Inter-Device Synchronization o IDES), com en entorns IDMS (Inter-Destination Media Synchronization o IDMS), incloent la sincronització d'efectes multisensorials. S'ha dissenyat i implementat una plataforma d'extrem a extrem per a la generació, distribució (adaptativa) i consum de contingut híbrid relacionat, tant en un sol dispositiu com en múltiples locals (p. ex., escenari multipantalla) o remots (p. ex., Social TV). dispositius. S'han generat i preparat contingut multimèdia tradicional (2D) i omnidireccional (360), enriquit amb efectes multisensorials que milloren el grau de realisme i immersivitat dels usuaris. La plataforma és compatible amb l'estàndard HbbTV i, a més, inclou solucions eficients per a aspectes clau que no s'especifiquen en aquest estàndard, però que són necessaris per a la implantació amb èxit de serveis de televisió híbrids i multidispositiu en el mateix, com ara: la necessitat per a un buffer per a continguts de difusió (existent i opcional fins a HbbTV 2. 0.2); mecanismes de senyalització, associació i descripció dels continguts disponibles i relacionats amb el contingut principal; mecanismes de coordinació i interacció entre dispositius de consum; o solucions de sincronització per alinear en el temps el consum de continguts de manera satisfactòria. Els resultats obtinguts en l'avaluació realitzada mostren que el nivell de sincronització adquirit entre els processos de reproducció dels diferents tipus de continguts disponibles a través de diferents tecnologies de transmissió assoleix valors suficients per proporcionar a l'usuari un consum amb un nivell d'asincronies imperceptibles. La precisió aconseguida ha donat com a resultat una QoE molt satisfactòria per al consumidor, oferint-li un ecosistema complet de consum de continguts que inclou tant contingut multimèdia tradicional com contingut omnidireccional i mulsemedia. / [EN] Currently, there is a wide variety of multimedia content distribution technologies, consumer devices, as well as types of content. In terms of distribution technologies, such content can be delivered either over broadcast networks, such as DVB networks, or over broadband networks, such as IP networks (e.g. over the Internet). The coordination and convergence between the two types of technologies to distribute related content offers great potential to content providers, as well as great benefits to consumers (a proof of this is the Hybrid Broadcast Broadband TV or HbbTV standard). However, the reception of related content from different hybrid networks (broadcast/broadband) entails significant delay variability, so a number of important challenges must be overcome, such as the need for mechanisms to ensure synchronized consumption of such content, either on the same device or on different devices (local or remote). We have specified, implemented and evaluated synchronization solutions for hybrid content playback processes (broadcast and/or broadband networks) both in multi-device environments, between local devices (Inter-Device Synchronization or IDES), and in multi-user environments, between distributed network recipients (Inter-Destination Media Synchronization or IDMS), including the synchronization of multi-sensory effects. An end-to-end platform has been designed and implemented for the generation, distribution (adaptive) and consumption of related hybrid content, both on a single device and on multiple local (e.g., multiscreen scenario) or remote (e.g., Social TV) devices. Traditional (2D) and omnidirectional (360) multimedia content has been generated and prepared, enriched with multisensory effects that enhance the degree of realism and immersiveness for users. The platform is compatible with the HbbTV standard and, in addition, includes efficient solutions for key aspects that are not specified in that standard, but are necessary for the successful implementation of hybrid and multi-device TV services on it, such as: the need for a buffer for broadcast content (existing and optional up to the HbbTV 2. 0.2); mechanisms for signaling, association and description of content available and related to the main content; coordination and interaction mechanisms between consumption devices; or synchronization solutions to align in time the consumption of content in a satisfactory way. The results obtained in the evaluation carried out show that the level of synchronization acquired between the reproduction processes of the different types of content available through different transmission technologies reaches sufficient values to provide the user with a consumption with an imperceptible level of asynchronies. The accuracy achieved has resulted in a very satisfactory QoE for the consumer, offering him a complete content consumption ecosystem that includes traditional multimedia content as well as omnidirectional and mulsemedia content. / Marfil Reguero, D. (2022). Especificación, implementación y evaluación de soluciones de sincronización multimedia híbrida (broadcast/broadband) e inter-destinatario para posibilitar nuevas experiencias televisivas enriquecidas, personalizadas, inmersivas y compartidas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185746 / TESIS

Page generated in 0.039 seconds