Der Vortrag zeigt die Neuigkeiten in PTC Creo Simulate 3.0 auf. Zudem werden 10 "Tips & Tricks" erklärt, welche das Arbeiten effizienter machen.

Der Vortrag beschreibt die zugrunde liegende Theorie und die Softwarefunktionalität des in PTC Creo Simulate 3.0 eingeführten Kontaktmodells mit endlicher Reibung und vergleicht dieses mit den bis Creo Simulate 2.0 exklusiv verwendeten Kontaktmodellen (ideal reibungsfrei und unendlich reibungsbehaftet). An zwei Modellbeispielen (ein von zwei Bremsbacken geklemmtes Bremsschwert und ein verschraubtes Schwungrad) wird versucht, die Funktionsweise des neuen Modells zu demonstrieren. Wegen aktueller Qualitätsprobleme der Software wird die Brauchbarkeit der Kontaktmodelle für den Anwender bewertet (Stand Creo 3.0 M080 / Creo 2.0 M200) und umfangreiches Feedback an den Softwarehersteller PTC gegeben. / The presentation describes the underlying theory and software functionality of the finite friction contact model introduced with PTC Creo Simulate 3.0. It is being compared with the friction-free and infinite friction contact model used exclusively until Creo Simulate 2.0. It is being tried to demonstrate the mode of operation of the new model with help of two examples: A brake sword clamped by two brake pads and a bolted flywheel. Because of actual software quality problems, the usability of the contact model for the user is being rated (status Creo 3.0 M080 / Creo 2.0 M200). Furthermore, comprehensive feedback is given to the software developer PTC.

L'épilepsie constitue le désordre neurologique le plus fréquent après les maladies cérébrovasculaires. Bien que le contrôle des crises se fasse généralement au moyen d'anticonvulsivants, environ 30 % des patients y sont réfractaires. Pour ceux-ci, la chirurgie de l'épilepsie s'avère une option intéressante, surtout si l’imagerie par résonance magnétique (IRM) cérébrale révèle une lésion épileptogène bien délimitée. Malheureusement, près du quart des épilepsies partielles réfractaires sont dites « non lésionnelles ». Chez ces patients avec une IRM négative, la délimitation de la zone épileptogène doit alors reposer sur la mise en commun des données cliniques, électrophysiologiques (EEG de surface ou intracrânien) et fonctionnelles (tomographie à émission monophotonique ou de positrons). La faible résolution spatiale et/ou temporelle de ces outils de localisation se traduit par un taux de succès chirurgical décevant. Dans le cadre de cette thèse, nous avons exploré le potentiel de trois nouvelles techniques pouvant améliorer la localisation du foyer épileptique chez les patients avec épilepsie focale réfractaire considérés candidats potentiels à une chirurgie d’épilepsie : l’IRM à haut champ, la spectroscopie proche infrarouge (SPIR) et la magnétoencéphalographie (MEG). Dans une première étude, nous avons évalué si l’IRM de haut champ à 3 Tesla (T), présentant théoriquement un rapport signal sur bruit plus élevé que l’IRM conventionnelle à 1,5 T, pouvait permettre la détection des lésions épileptogènes subtiles qui auraient été manquées par cette dernière. Malheureusement, l’IRM 3 T n’a permis de détecter qu’un faible nombre de lésions épileptogènes supplémentaires (5,6 %) d’où la nécessité d’explorer d’autres techniques. Dans les seconde et troisième études, nous avons examiné le potentiel de la SPIR pour localiser le foyer épileptique en analysant le comportement hémodynamique au cours de crises temporales et frontales. Ces études ont montré que les crises sont associées à une augmentation significative de l’hémoglobine oxygénée (HbO) et l’hémoglobine totale au niveau de la région épileptique. Bien qu’une activation contralatérale en image miroir puisse être observée sur la majorité des crises, la latéralisation du foyer était possible dans la plupart des cas. Une augmentation surprenante de l’hémoglobine désoxygénée a parfois pu être observée suggérant qu’une hypoxie puisse survenir même lors de courtes crises focales. Dans la quatrième et dernière étude, nous avons évalué l’apport de la MEG dans l’évaluation des patients avec épilepsie focale réfractaire considérés candidats potentiels à une chirurgie. Il s’est avéré que les localisations de sources des pointes épileptiques interictales par la MEG ont eu un impact majeur sur le plan de traitement chez plus des deux tiers des sujets ainsi que sur le devenir postchirurgical au niveau du contrôle des crises. / Epilepsy is the most common chronic neurological disorder after stroke. The major form of treatment is long-term drug therapy to which approximately 30% of patients are unfortunately refractory to. Brain surgery is recommended when medication fails, especially if magnetic resonance imaging (MRI) can identify a well-defined epileptogenic lesion. Unfortunately, close to a quarter of patients have nonlesional refractory focal epilepsy. For these MRI-negative cases, identification of the epileptogenic zone rely heavily on remaining tools: clinical history, video-electroencephalography (EEG) monitoring, ictal single-photon emission computed tomography (SPECT), and a positron emission tomography (PET). Unfortunately, the limited spatial and/or temporal resolution of these localization techniques translates into poor surgical outcome rates. In this thesis, we explore three relatively novel techniques to improve the localization of the epileptic focus for patients with drug-resistant focal epilepsy who are potential candidates for epilepsy surgery: high-field 3 Tesla (T) MRI, near-infrared spectroscopy (NIRS) and magnetoencephalography (MEG). In the first study, we evaluated if high-field 3T MRI, providing a higher signal to noise ratio, could help detect subtle epileptogenic lesions missed by conventional 1.5T MRIs. Unfortunately, we show that the former was able to detect an epileptogenic lesion in only 5.6% of cases of 1.5T MRI-negative epileptic patients, emphasizing the need for additional techniques. In the second and third studies, we evaluated the potential of NIRS in localizing the epileptic focus by analyzing the hemodynamic behavior of temporal and frontal lobe seizures respectively. We show that focal seizures are associated with significant increases in oxygenated haemoglobin (HbO) and total haemoglobin (HbT) over the epileptic area. While a contralateral mirror-like activation was seen in the majority of seizures, lateralization of the epileptic focus was possible most of the time. In addition, an unexpected increase in deoxygenated haemoglobin (HbR) was noted in some seizures, suggesting possible hypoxia even during relatively brief focal seizures. In the fourth and last study, the utility of MEG in the evaluation of nonlesional drug-refractory focal epileptic patients was studied. It was found that MEG source localization of interictal epileptic spikes had an impact both on patient management for over two thirds of patients and their surgical outcome.

L'épilepsie constitue le désordre neurologique le plus fréquent après les maladies cérébrovasculaires. Bien que le contrôle des crises se fasse généralement au moyen d'anticonvulsivants, environ 30 % des patients y sont réfractaires. Pour ceux-ci, la chirurgie de l'épilepsie s'avère une option intéressante, surtout si l’imagerie par résonance magnétique (IRM) cérébrale révèle une lésion épileptogène bien délimitée. Malheureusement, près du quart des épilepsies partielles réfractaires sont dites « non lésionnelles ». Chez ces patients avec une IRM négative, la délimitation de la zone épileptogène doit alors reposer sur la mise en commun des données cliniques, électrophysiologiques (EEG de surface ou intracrânien) et fonctionnelles (tomographie à émission monophotonique ou de positrons). La faible résolution spatiale et/ou temporelle de ces outils de localisation se traduit par un taux de succès chirurgical décevant. Dans le cadre de cette thèse, nous avons exploré le potentiel de trois nouvelles techniques pouvant améliorer la localisation du foyer épileptique chez les patients avec épilepsie focale réfractaire considérés candidats potentiels à une chirurgie d’épilepsie : l’IRM à haut champ, la spectroscopie proche infrarouge (SPIR) et la magnétoencéphalographie (MEG). Dans une première étude, nous avons évalué si l’IRM de haut champ à 3 Tesla (T), présentant théoriquement un rapport signal sur bruit plus élevé que l’IRM conventionnelle à 1,5 T, pouvait permettre la détection des lésions épileptogènes subtiles qui auraient été manquées par cette dernière. Malheureusement, l’IRM 3 T n’a permis de détecter qu’un faible nombre de lésions épileptogènes supplémentaires (5,6 %) d’où la nécessité d’explorer d’autres techniques. Dans les seconde et troisième études, nous avons examiné le potentiel de la SPIR pour localiser le foyer épileptique en analysant le comportement hémodynamique au cours de crises temporales et frontales. Ces études ont montré que les crises sont associées à une augmentation significative de l’hémoglobine oxygénée (HbO) et l’hémoglobine totale au niveau de la région épileptique. Bien qu’une activation contralatérale en image miroir puisse être observée sur la majorité des crises, la latéralisation du foyer était possible dans la plupart des cas. Une augmentation surprenante de l’hémoglobine désoxygénée a parfois pu être observée suggérant qu’une hypoxie puisse survenir même lors de courtes crises focales. Dans la quatrième et dernière étude, nous avons évalué l’apport de la MEG dans l’évaluation des patients avec épilepsie focale réfractaire considérés candidats potentiels à une chirurgie. Il s’est avéré que les localisations de sources des pointes épileptiques interictales par la MEG ont eu un impact majeur sur le plan de traitement chez plus des deux tiers des sujets ainsi que sur le devenir postchirurgical au niveau du contrôle des crises. / Epilepsy is the most common chronic neurological disorder after stroke. The major form of treatment is long-term drug therapy to which approximately 30% of patients are unfortunately refractory to. Brain surgery is recommended when medication fails, especially if magnetic resonance imaging (MRI) can identify a well-defined epileptogenic lesion. Unfortunately, close to a quarter of patients have nonlesional refractory focal epilepsy. For these MRI-negative cases, identification of the epileptogenic zone rely heavily on remaining tools: clinical history, video-electroencephalography (EEG) monitoring, ictal single-photon emission computed tomography (SPECT), and a positron emission tomography (PET). Unfortunately, the limited spatial and/or temporal resolution of these localization techniques translates into poor surgical outcome rates. In this thesis, we explore three relatively novel techniques to improve the localization of the epileptic focus for patients with drug-resistant focal epilepsy who are potential candidates for epilepsy surgery: high-field 3 Tesla (T) MRI, near-infrared spectroscopy (NIRS) and magnetoencephalography (MEG). In the first study, we evaluated if high-field 3T MRI, providing a higher signal to noise ratio, could help detect subtle epileptogenic lesions missed by conventional 1.5T MRIs. Unfortunately, we show that the former was able to detect an epileptogenic lesion in only 5.6% of cases of 1.5T MRI-negative epileptic patients, emphasizing the need for additional techniques. In the second and third studies, we evaluated the potential of NIRS in localizing the epileptic focus by analyzing the hemodynamic behavior of temporal and frontal lobe seizures respectively. We show that focal seizures are associated with significant increases in oxygenated haemoglobin (HbO) and total haemoglobin (HbT) over the epileptic area. While a contralateral mirror-like activation was seen in the majority of seizures, lateralization of the epileptic focus was possible most of the time. In addition, an unexpected increase in deoxygenated haemoglobin (HbR) was noted in some seizures, suggesting possible hypoxia even during relatively brief focal seizures. In the fourth and last study, the utility of MEG in the evaluation of nonlesional drug-refractory focal epileptic patients was studied. It was found that MEG source localization of interictal epileptic spikes had an impact both on patient management for over two thirds of patients and their surgical outcome.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-09-22T13:19:07Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_InterfacesGraficasEntrada.pdf: 2071188 bytes, checksum: 57a00616df244bb00fec10e728b8a9a1 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-09-29T15:15:23Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_InterfacesGraficasEntrada.pdf: 2071188 bytes, checksum: 57a00616df244bb00fec10e728b8a9a1 (MD5) / Made available in DSpace on 2014-09-29T15:15:23Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_InterfacesGraficasEntrada.pdf: 2071188 bytes, checksum: 57a00616df244bb00fec10e728b8a9a1 (MD5) Previous issue date: 2005 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Apresentamos uma interface gráfica para o programa eGs (electrical GEOPHYSICS suíte) usado na modelagem e interpretação de dados elétricos e eletromagnéticos na exploração geofísica. Esta dissertação corresponde a parcela do programa que trata das interfaces de entrada de dados de modelos geoelétricos bi e tridimensionais e das interfaces de apresentação dos resultados da modelagem como também dos dados observados. O programa contém interfaces para criação, modificação e visualização de modelos geoelétricos bi e tridimensionais, e para apresentação da resposta do modelo através de gráficos e imagens. Este trabalho resultou num programa com diversas opções para alterar a geometria e as propriedades físicas do modelo geoelétricos e recursos de visualização para facilitar a interpretação de dados geofísicos. A interface gráfica pode ser usada para criar modelos geoelétricos dos métodos elétrico ou eletromagnético mais usados e analisar as respostas dos modelos e de dados observados em campanha de campo. O programa é suficientemente flexível de modo que novas interfaces gráficas de outros métodos elétricos e eletromagnéticos podem ser facilmente implementadas. / We present a graphic interface for the program eGs (electrical GEOPHYSICS suite) used for modeling and interpretation of electric and electromagnetic data in geophysical exploration. This master degree dissertation corresponds the portion of the program that treats the interfaces for bi and three-dimensional input data of geoelectrical models together with interfaces for the presentation of the modeling results and for the presentation of observed data as well. The program contains interfaces for creation, modification and visualization of bi and threedimensional geoelectrical models and for illustrations of the calculated results through graphs and images. This work gives a program with several options to alter the geometry and the physical properties of the geoelectrical models, including facilities for three dimensions visualization in order to help geophysical data interpretation. The graphic interfaces can be used to create geoelectrical models associated with the most used electric and electromagnetic geophysical methods and to analyze the answers obtained by numerical modeling associated with different types of observed data in field campaign. The program is sufficiently flexible so that new graphic interfaces of other electric and electromagnetic methods can be implemented easily.

Made available in DSpace on 2018-08-01T23:40:20Z (GMT). No. of bitstreams: 1 tese_10014_LARISSA SINCORÁ - DISSERTAÇÃO_VERSÃO FINAL_CAPA DURA.pdf: 2216917 bytes, checksum: 9fa69e4311823dccf2820e6e65e9abbf (MD5) Previous issue date: 2016-06-20 / CAPES / Esta dissertação foi desenvolvida com o intuito de avaliar o papel exercido pelas capabilidades analíticas organizacionais quando relacionadas à maturidade de gestão de processos de negócio e à resiliência organizacional. A motivação para o estudo, por sua vez, se insere num contexto no qual a sobrevivência e o crescimento das organizações estão ligados às suas capabilidades de efetivamente utilizar grandes volumes de dados provenientes de diferentes fontes para auxiliar em suas orientações estratégicas e operacionais, constituindo atualmente um fator crítico para o sucesso. Isto se evidencia porque diversas empresas, de diferentes segmentos de atuação, e de várias partes do mundo, têm adotado a abordagem analítica como um diferencial competitivo em suas operações com capacidade de influenciar as demais variáveis organizacionais. Por conseguinte, a partir da fundamentação teórica dos construtos, foi possível identificar seus domínios e formas de operacionalização, bem como as relações teóricas existentes, o que resultou no delineamento do modelo teórico da pesquisa e no questionário do tipo survey. Quanto ao percurso metodológico, a aplicação do questionário foi conduzida pelo IEL/FINDES (Instituto Euvaldo Lodi vinculado à Federação das Indústrias do Estado do Espírito Santo) a partir do envio de carta-convite aos informantes-chave da pesquisa, durante os meses de setembro a dezembro de 2015. Dessa maneira, a técnica de análise de dados empregada para avaliar as relações hipotetizadas e a qualidade do modelo teórico elaborado, consistiu-se na modelagem de equações estruturais, por meio do software Smart PLS-SEM 3.0, baseado no algoritmo dos mínimos quadrados parciais (PLS-SEM). Em seguida, após o tratamento dos dados, os resultados foram interpretados e discutidos, apontando para a existência de relações estatisticamente significativas e coerentes com o aporte teórico. Logo, foi possível concluir que as capabilidades analíticas organizacionais atuam como antecedentes de resiliência organizacional, bem como desempenham o papel de moderar a relação existente entre a maturidade de gestão de processos de negócio e a resiliência organizacional. Por fim, se teceu as considerações finais, contendo as limitações do estudo, as contribuições para a evolução dos temas pesquisados e as recomendações de futuras pesquisas em tópicos tangentes às respectivas temáticas investigadas. / This work was developed in order to evaluate the role played by organizational analytical capabilities as they relate to business processes management maturity and organizational resilience. The motivation for the study, in turn, is a part of a context in which the survival and growth of organizations are connected to their capabilities to effectively use large amounts of data from different sources to assist in their strategic and operational guidelines, being currently a critical success factor. It becomes clear because several companies from different segments and in various parts of the world have adopted the analytical approach as a operational competitive advantage, with the ability to influence other organizational variables. Therefore, through the theoretical foundations of the constructs were identified domains and forms of implementation, as well the existing theoretical relationships, which resulted in the delineation of the theoretical research model and the questionnaire used for the survey. As for the methodological approach, the questionnaire was conducted by IEL/FINDES (Institute Euvaldo Lodi linked to the Federation of Industries of the State Espírito Santo) from sending an invitation letter to key-informants of the research, during the months of September to December 2015. Thus, the data analysis technique used to evaluate the hypothesized relationships and the quality of the developed theoretical model consisted on structural equation modeling by using the software Smart PLS-SEM 3.0, based on the algorithm of partial least squares (PLS-SEM). Therefore, it was concluded that the organizational analytical capabilities acts as organizational resilience antecedents, as well plays the role of moderating the relationship between the business processes management maturity and organizational resilience. In addition, after data treatment, the results were analyzed and discussed, pointing to the existence of statistically significant and consistent relations with the theoretical framework. Finally, were made the final considerations, exposing the study's limitations, the contributions to the evolution of the researched topics, and future research recommendations on tangential topics related to the themes investigated.

This thesis describes digital television transition in the United States. Its goal is to introduce the way how digital television broadcasting in the United States was formed and analog broadcasting was switched off, and how these changes affected American television market and usage of broadcasting spectrum. In the first part I explain a context in which American television market has been formed and has developed until the beginning of 1990s, when the debate about digital television broadcasting commenced. Reason for a development of the new television norm was a desire to broadcast in high definition. Establishment of ATSC norm is explained in 4th chapter. Following chapter describes how digital television coverage grew and what the expenses were for viewers. The thesis then describes spectrum auctions and changes in the television market which digital television transition brought. When the transition ended need for a new debate about television emerged because current norm is becoming obsolete and did not allow broadcasting in ultra high definition. This lead to the development of ATSC 3.0 norm which allows broadcasting more programs in terrestrial television broadcasting and allows expanding terrestrial broadcasting to other mobile devices.

This dissertation thesis is focused at opportunities in real estate industry in connection with using internet based portal for real estate agencies. The thesis is based on Čestmír Kadlec's dissertation thesis which presents a methodology for creating real estate agencies portal. The main aim of this paper is to specify a concept of real estate agencies portal web pages according to methodology developed by Kadlec and evaluate required investment into development and operation the real estate agencies internet based portal. Firstly, theoretical part deals with information society, real estate market in the Czech Republic and how the evolution of information society influenced Czech real estate market in the past. Also the thesis contains description of real estate agency portals in the Czech Republic, their typology and a selection of a web portal for further analysis. The analysis of Sreality.cz contains a description of key processes and also description and fees of provided services. Practical part is focused at specification of real estate agencies web portal according to Kadlec's methodology which can be found in his dissertation thesis. Firstly, there is a description of real estate agencies portal as a system. Then there is an assessment how the proposed solutions meets the criteria specified by Kadlec, which the "ideal" web portal must have. In conclusion, the business case was prepared to Compaq the costs of development and operation of the portal and potential revenues according to competition market analysis. The outcome of the whole thesis is a recommendation whether the investment in the portal makes business sense.

The modern swedish atheism is led by Christer Sturmark, chairman of Humanisterna, the swedish humanists. In this essay I study the epistemology of Christer Sturmark to find out on what basis he makes his assumptions about knowledge, faith, belief and his view that scientism is the only way to reach real knowledge. I present a closer historical look at the research about and philosophy of epistemology in general and then I analyze Christer Sturmarks book "Tro och Vetande 3.0 - Upplysning i det 21:a århundradet" and compare the views presented in that book to historical and contemporary philopsohers and religous scholars to extract the epistemology of Christer Sturmark, as it is presented in his book. To gain a more thorough understanding of his epistemolgy, I then compare his view to the swedish churchs´view of God as omnipotent. Finally I present a conclusion about the nature of Christer Sturmarks epistemology, if it is logically consistent and how it relates to the way humans can organize their understanding of the world.

Nowadays, the digital terrestrial television (DTT) market is characterized by the high capacity needed for high definition TV services. There is a need for an efficient use of the broadcast spectrum, which requires new technologies to guarantee increased capacities. Non-Uniform Constellations (NUC) arise as one of the most innovative techniques to approach those requirements. NUCs reduce the gap between uniform Gray-labelled Quadrature Amplitude Modulation (QAM) constellations and the theoretical unconstrained Shannon limit. With these constellations, symbols are optimized in both in-phase (I) and quadrature (Q) components by means of signal geometrical shaping, considering a certain signal-to-noise ratio (SNR) and channel model. There are two types of NUC, one-dimensional and two-dimensional NUCs (1D-NUC and 2D-NUC, respectively). 1D-NUCs maintain the squared shape from QAM, but relaxing the distribution between constellation symbols in a single component, with non-uniform distance between them. These constellations provide better SNR performance than QAM, without any demapping complexity increase. 2D-NUCs also relax the square shape constraint, allowing to optimize the symbol positions in both dimensions, thus achieving higher capacity gains and lower SNR requirements. However, the use of 2D-NUCs implies a higher demapping complexity, since a 2D-demapper is needed, i.e. I and Q components cannot be separated. In this dissertation, NUCs are analyzed from both transmit and receive point of views, using either single-input single-output (SISO) or multiple-input multiple-output (MIMO) antenna configurations. In SISO transmissions, 1D-NUCs and 2D-NUCs are optimized for a wide range of SNRs and different constellation orders. The optimization of rotated 2D-NUCs is also investigated. Even though the demapping complexity is not increased, the SNR gain of these constellations is not significant. The highest rotation gain is obtained for low-order constellations and high SNRs. However, with multi-RF techniques, the SNR gain is drastically increased, since I and Q components are transmitted in different RF channels. In this thesis, multi-RF gains of NUCs with and without rotation are provided for some representative scenarios. At the receiver, two different implementation bottlenecks are explored. First, the demapping complexity of all considered constellations is analyzed. Afterwards, two complexity reduction algorithms for 2D-NUCs are proposed. Both algorithms drastically reduce the number of distances to compute. Moreover, both are finally combined in a single demapper. Quantization of NUCs is also explored in this dissertation, since LLR values and I/Q components are modified when using these constellations, compared to traditional QAM constellations. A new algorithm that is based on the optimization of the quantizer levels for a particular constellation is proposed. The use of NUCs in multi-antenna communications is also investigated. It includes the optimization in one or two antennas, the use of power imbalance, the cross-polar discrimination (XPD) between receive antennas, or the use of different demappers. Assuming different values for the parameters evaluated, new Multi-Antenna Non-Uniform Constellations (MA-NUC) are obtained by means of a particularized re-optimization process, specific for MIMO. At the receiver, an extended demapping complexity analysis is performed, where it is shown that the use of 2D-NUCs in MIMO extremely increases the demapping complexity. As an alternative, an efficient solution for 2D-NUCs and MIMO systems based on Soft-Fixed Sphere Decoding (SFSD) is proposed. The main drawback is that SFSD demappers do not work with 2D-NUCs, since they perform a Successive Interference Cancellation (SIC) step that needs to be performed in separated I and Q components. The proposed method quantifies the closest symbol using Voronoi regions and allows SFSD demappers to work. / Hoy en día, el mercado de la televisión digital terrestre (TDT) está caracterizado por la alta capacidad requerida para transmitir servicios de televisión de alta definición y el espectro disponible. Es necesario por tanto un uso eficiente del espectro radioeléctrico, el cual requiere nuevas tecnologías para garantizar mayores capacidades. Las constelaciones no-uniformes (NUC) emergen como una de las técnicas más innovadoras para abordar tales requerimientos. Las NUC reducen el espacio existente entre las constelaciones uniformes QAM y el límite teórico de Shannon. Con estas constelaciones, los símbolos se optimizan en ambas componentes fase (I) y cuadratura (Q) mediante técnicas geométricas de modelado de la señal, considerando un nivel señal a ruido (SNR) concreto y un modelo de canal específico. Hay dos tipos de NUC, unidimensionales y bidimensionales (1D-NUC y 2D-NUC, respectivamente). Las 1D-NUC mantienen la forma cuadrada de las QAM, pero permiten cambiar la distribución entre los símbolos en una componente concreta, teniendo una distancia no uniforme entre ellos. Estas constelaciones proporcionan un mejor rendimiento SNR que QAM, sin ningún incremento en la complejidad en el demapper. Las 2D-NUC también permiten cambiar la forma cuadrada de la constelación, permitiendo optimizar los símbolos en ambas dimensiones y por tanto obteniendo mayores ganancias en capacidad y menores requerimientos en SNR. Sin embargo, el uso de 2D-NUCs implica una mayor complejidad en el receptor. En esta tesis se analizan las NUC desde el punto de vista tanto de transmisión como de recepción, utilizando bien configuraciones con una antena (SISO) o con múltiples antenas (MIMO). En transmisiones SISO, se han optimizado 1D-NUCs para un rango amplio de distintas SNR y varios órdenes de constelación. También se ha investigado la optimización de 2D-NUCs rotadas. Aunque la complejidad no aumenta, la ganancia SNR de estas constelaciones no es significativa. La mayor ganancia por rotación se obtiene para bajos órdenes de constelación y altas SNR. Sin embargo, utilizando técnicas multi-RF, la ganancia aumenta drásticamente puesto que las componentes I y Q se transmiten en distintos canales RF. En esta tesis, se han estudiado varias ganancias multi-RF representativas de las NUC, con o sin rotación. En el receptor, se han identificado dos cuellos de botella diferentes en la implementación. Primero, se ha analizado la complejidad en el receptor para todas las constelaciones consideradas y, posteriormente, se proponen dos algoritmos para reducir la complejidad con 2D-NUCs. Además, los dos pueden combinarse en un único demapper. También se ha explorado la cuantización de estas constelaciones, ya que tanto los valores LLR como las componentes I/Q se ven modificados, comparando con constelaciones QAM tradicionales. Además, se ha propuesto un algoritmo que se basa en la optimización para diferentes niveles de cuantización, para una NUC concreta. Igualmente, se ha investigado en detalle el uso de NUCs en MIMO. Se ha incluido la optimización en una sola o en dos antenas, el uso de un desbalance de potencia, factores de discriminación entre antenas receptoras (XPD), o el uso de distintos demappers. Asumiendo distintos valores, se han obtenido nuevas constelaciones multi-antena (MA-NUC) gracias a un nuevo proceso de re-optimización específico para MIMO. En el receptor, se ha extendido el análisis de complejidad en el demapper, la cual se incrementa enormemente con el uso de 2D-NUCs y sistemas MIMO. Como alternativa, se propone una solución basada en el algoritmo Soft-Fixed Sphere Decoding (SFSD). El principal problema es que estos demappers no funcionan con 2D-NUCs, puesto que necesitan de un paso adicional en el que las componentes I y Q necesitan separarse. El método propuesto cuantifica el símbolo más cercano utilizando las regiones de Voronoi, permitiendo el uso de este tipo de receptor. / Actualment, el mercat de la televisió digital terrestre (TDT) està caracteritzat per l'alta capacitat requerida per a transmetre servicis de televisió d'alta definició i l'espectre disponible. És necessari per tant un ús eficient de l'espectre radioelèctric, el qual requereix noves tecnologies per a garantir majors capacitats i millors servicis. Les constel·lacions no-uniformes (NUC) emergeixen com una de les tècniques més innovadores en els sistemes de televisió de següent generació per a abordar tals requeriments. Les NUC redueixen l'espai existent entre les constel·lacions uniformes QAM i el límit teòric de Shannon. Amb estes constel·lacions, els símbols s'optimitzen en ambdós components fase (I) i quadratura (Q) per mitjà de tècniques geomètriques de modelatge del senyal, considerant un nivell senyal a soroll (SNR) concret i un model de canal específic. Hi ha dos tipus de NUC, unidimensionals i bidimensionals (1D-NUC i 2D-NUC, respectivament). 1D-NUCs mantenen la forma quadrada de les QAM, però permet canviar la distribució entre els símbols en una component concreta, tenint una distància no uniforme entre ells. Estes constel·lacions proporcionen un millor rendiment SNR que QAM, sense cap increment en la complexitat al demapper. 2D-NUC també canvien la forma quadrada de la constel·lació, permetent optimitzar els símbols en ambdós dimensions i per tant obtenint majors guanys en capacitat i menors requeriments en SNR. No obstant això, l'ús de 2D-NUCs implica una major complexitat en el receptor, ja que es necessita un demapper 2D, on les components I i Q no poden ser separades. En esta tesi s'analitzen les NUC des del punt de vista tant de transmissió com de recepció, utilitzant bé configuracions amb una antena (SISO) o amb múltiples antenes (MIMO). En transmissions SISO, s'han optimitzat 1D-NUCs, per a un rang ampli de distintes SNR i diferents ordes de constel·lació. També s'ha investigat l'optimització de 2D-NUCs rotades. Encara que la complexitat no augmenta, el guany SNR d'estes constel·lacions no és significativa. El major guany per rotació s'obté per a baixos ordes de constel·lació i altes SNR. No obstant això, utilitzant tècniques multi-RF, el guany augmenta dràsticament ja que les components I i Q es transmeten en distints canals RF. En esta tesi, s'ha estudiat el guany multi-RF de les NUC, amb o sense rotació. En el receptor, s'han identificat dos colls de botella diferents en la implementació. Primer, s'ha analitzat la complexitat en el receptor per a totes les constel·lacions considerades i, posteriorment, es proposen dos algoritmes per a reduir la complexitat amb 2D-NUCs. Ambdós algoritmes redueixen dràsticament el nombre de distàncies. A més, els dos poden combinar-se en un únic demapper. També s'ha explorat la quantització d'estes constel·lacions, ja que tant els valors LLR com les components I/Q es veuen modificats, comparant amb constel·lacions QAM tradicionals. A més, s'ha proposat un algoritme que es basa en l'optimització per a diferents nivells de quantització, per a una NUC concreta. Igualment, s'ha investigat en detall l'ús de NUCs en MIMO. S'ha inclòs l'optimització en una sola o en dos antenes, l'ús d'un desbalanç de potència, factors de discriminació entre antenes receptores (XPD), o l'ús de distints demappers. Assumint distints valors, s'han obtingut noves constel·lacions multi-antena (MA-NUC) gràcies a un nou procés de re-optimització específic per a MIMO. En el receptor, s'ha modificat l'anàlisi de complexitat al demapper, la qual s'incrementa enormement amb l'ús de 2D-NUCs i sistemes MIMO. Com a alternativa, es proposa una solució basada en l'algoritme Soft-Fixed Sphere Decoding (SFSD) . El principal problema és que estos demappers no funcionen amb 2D-NUCs, ja que necessiten d'un pas addicional en què les components I i Q necessiten separar-se. El mètode proposat quantifica el símbol més pròxim utilitzan / Fuentes Muela, M. (2017). Non-Uniform Constellations for Next-Generation Digital Terrestrial Broadcast Systems [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84743