Adaptive relaying protocol multiple-input multiple-output orthogonal frequency division multiplexing systems

In wireless broadband communications, orthogonal frequency division multiplexing (OFDM) has been adopted as a promising technique to mitigate multi-path fading and provide high spectral efficiency. In addition, cooperative communication can explore spatial diversity where several users or nodes share their resources and cooperate through distributed transmission. The concatenation of the OFDM technique with relaying systems can enhance the overall performance in terms of spectral efficiency and improve robustness against the detrimental effects of fading. Hybrid relay selection is proposed to overcome the drawbacks of conventional forwarding schemes. However, exciting hybrid relay protocols may suffer some limitations when used for transmission over frequency-selective channels. The combination of cooperative protocols with OFDM systems has been extensively utilized in current wireless networks, and have become a promising solution for future high data rate broadband communication systems including 3D video transmission. This thesis covers two areas of high data rate networks. In the first part, several techniques using cooperative OFDM systems are presented including relay selection, space time block codes, resource allocation and adaptive bit and power allocation to introduce diversity. Four (4) selective OFDM relaying schemes are studied over wireless networks; selective OFDM; selective OFDMA; selective block OFDM and selective unequal block OFDM. The closed-form expression of these schemes is derived. By exploiting the broadcast nature, it is demonstrated that spatial diversity can be improved. The upper bound of outage probability for the protocols is derived. A new strategy for hybrid relay selection is proposed to improve the system performance by removing the sub-carriers that experience deep fading. The per subcarrier basis selection is considered with respect to the predefined threshold signal-to-noise ratio. The closed-form expressions of the proposed protocol in terms of bit error probability and outage probability are derived and compared with conventional hybrid relay selection. Adaptive bit and power allocation is also discussed to improve the system performance. Distributed space frequency coding applied to hybrid relay selection to obtain full spatial and full data rate transmission is explored. Two strategies, single cluster and multiple clusters, are considered for the Alamouti code at the destination by using a hybrid relay protocol. The power allocation with and without sub-carrier pairing is also investigated to mitigate the effect of multipath error propagation in frequency-selective channels. The second part of this thesis investigates the application of cooperative OFDM systems to high data rate transmission. Recently, there has been growing attention paid to 3D video transmission over broadband wireless channels. Two strategies for relay selection hybrid relay selection and first best second best are proposed to implement unequal error protection in the physical layer over error prone channels. The closed-form expressions of bit error probability and outage probability for both strategies are examined. The peak signal-to-noise ratio is presented to show the quality of reconstruction of the left and right views

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences

Saving Bones: a direct comparison of FTIR-ATR, whole bone percent nitrogen, and NIR

89th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA), Los Angeles, CA, APR 15-18, 202

La Titulización: Origen, Evolución y Regulación Actual en La U.E y en España

La tesis examina la relación entre el papel de la titulización en la crisis financiera de 2007 y la regulación de la titulización en Europa en general y en España en particular. La tesis tiene dos objetivos principales e interconectados. a) El primero es demostrar que la convergencia de la titulización y las permutas de incumplimiento crediticio en el contexto del mercado hipotecario residencial estadounidense fue un catalizador de la gran crisis financiera (en adelante, la GCF), y que esto fue posible gracias a la decisión política de rechazar radicalmente una tradición de derecho consuetudinario para tratar los derivados que tiene sus raíces en la Gran Bretaña del siglo XVIII. Para argumentar esto, la tesis rastrea el desarrollo de la titulización desde sus primeras formas europeas hasta su incorporación en instrumentos derivados altamente complejos en EE.UU. en vísperas de la GCF. También sigue la evolución jurídica coetánea de los instrumentos derivados en la tradición del Derecho Común y argumenta que fue la presión política por parte del sector bancario a finales del siglo XX la que provocó una ruptura radical en su tratamiento, y posteriormente permitió que desempeñaran un papel tan importante en la GCF. La tesis presenta el argumento de que la titulización hipotecaria fue un catalizador más que una causa primaria de la GCF, y que su papel fundamental fue el de exponer las debilidades estructurales del sistema bancario, en particular la dependencia de la financiación a corto plazo a través de acuerdos de recompra y la venta de papel comercial. Desde este punto de vista, las deficientes medidas de divulgación o la falta de "piel en el juego" en el mercado de titulización estadounidense no fueron responsables de la crisis. Más bien fue causada principalmente por una combinación de la fuerte inversión de las entidades de crédito en las cadenas de suministro de titulización integradas, junto con su dependencia de los mercados de deuda a corto plazo para la financiación. La opacidad de las estructuras de los SIV que negociaban deuda a corto plazo significó que, cuando los precios de la vivienda cayeron y los valores de alto riesgo comenzaron a incumplir en volúmenes significativos, los operadores, incapaces de determinar el contenido de los SIV, se negaron a refinanciar las obligaciones de deuda a corto plazo. Esto provocó una congelación de la oferta de crédito y supuso que las cadenas de suministro de titulización integradas no pudieran seguir financiando los productos asegurados con derivados para cuyo creación y comercialización habían sido creadas, y se vieron obligadas a absorber fuertes pérdidas en los productos altamente apalancados que ya no podían vender. b) El segundo objetivo de la tesis, que se desprende del primero, es demostrar que el cuerpo principal del Reglamento Europeo de Titulización, con su fuerte enfoque en los requisitos de divulgación y retención de riesgos y su promoción de la titulización simple, transparente y estandarizada, proporciona poco de sustancia a la titulización hipotecaria residencial española que no haya tenido ya desde sus orígenes, y que el Reglamento fue concebido como reacción a algunas de las causas percibidas de la crisis en EE. UU., en particular la creencia de que el modelo de originar para distribuir fue la causa de la crisis y que un gran número de compradores de bonos de titulización fueron incapaces de descifrar la complejidad de los instrumentos que adquirieron y, por tanto, no apreciaron plenamente los riesgos que entrañaban. Estas suposiciones son cuestionadas por las pruebas acumuladas en el texto. Conservar grandes cantidades de obligaciones de deuda colateralizada en el balance, o tener que absorber las pérdidas de los SIV que se vieron obligados a cerrar, resultaron ser unos de los mayores problemas para las entidades de crédito durante la GCF. Mientras la complejidad de los instrumentos financieros utilizados no fue en sí misma un impedimento para que los inversores profesionales sofisticados comprendieran los posibles riesgos que entrañaban los productos que adquirían, sino que la diligencia debida por parte de los compradores se suspendió a menudo en un intento frenético de cerrar las operaciones rápidamente para conseguir el mejor precio posible. La tesis se divide en cinco capítulos. El primer capítulo explica los mecanismos de titulización y el funcionamiento de los bancos en la sombra en el contexto de la financiarización de la economía estadounidense. El segundo capítulo recorre los orígenes de la técnica de la titulización, desde la cruda agricultura fiscal en el mundo antiguo hasta la primera titulización de marca privada en Estados Unidos. El tercer capítulo estudia el desarrollo de los derivados y la formación de un marco normativo en las jurisdicciones de derecho consuetudinario, primero en el Reino Unido y luego en EE.UU. El cuarto capítulo explora las formas en que la titulización actuó como catalizador y vector de la crisis financiera, exponiendo las debilidades estructurales de la economía estadounidense. El último capítulo se centra en la respuesta europea, enfocándose en dos piezas de legislación clave, el Reglamento (UE) 2017/2402 que creó un marco general para la titulización y un marco específico para la titulización simple, transparente y estandarizada, y la Ley 5/2015 que unificó la regulación dispersa de la titulización en España.The thesis examines the relationship between the role of securitisation in the financial crisis of 2007 and the regulation of securitisation in Europe in general and Spain in particular. The thesis has two principal and interconnected objectives. a) The first is to show that the convergence of securitisation and credit default swaps in the context of the U.S residential mortgage market was a catalyst for the great financial crisis (hereinafter the GFC), and that this was made possible by the political decision to radically reject a Common Law tradition of dealing with derivatives that has its roots in 18th century Britain. In order to make this argument the thesis traces the development of securitisation from its earliest European forms to its incorporation in highly complex derivative instruments in the U.S at the eve of the GFC. It also follows the cotemporaneous legal evolution of derivative instruments in the Common Law tradition and argues that it was political pressure on the part of the banking industry in the late twentieth century that caused a radical break in their treatment, and subsequently allowed them to play such a key role in the GFC. The thesis presents the case that mortgage securitisation was a catalyst rather than a primary cause of the GFC, and that its fundamental role was that of exposing structural weaknesses in the banking system, particularly the dependence on short-term funding through repurchase agreements and the sale of commercial paper. On this view, poor disclosure measures or a lack of “skin in the game” in the U.S Securitisation market were not responsible for the crisis. Rather it was primarily caused by a combination of the heavy investment of credit entities in integrated securitisation supply chains coupled with their dependence on the short-term debt markets for funding. The opaqueness of the SIV structures that traded in short-term debt meant that, when housing prices fell and subprime securities began to default in significant volumes, traders, unable to determine the content of the SIVs, refused to roll – over short term debt obligations. This caused a freeze in the supply of credit and meant that the integrated securitisation supply chains were unable to keep funding the derivative insured products they had been created to package and market, and were forced to absorb heavy losses on the highly leveraged products they could no longer sell. b) The second objective of the thesis, which follows on from the first, is to demonstrate that the main body of the European Securitisation Regulation, with its heavy focus on disclosure and risk retention requirements and its promotion of simple, transparent and standardized securitisation, provides little of substance to Spanish residential mortgage securitisation that it has not already had since its origins, and that the Regulation was conceived in reaction to some of the perceived causes of the crisis in the U.S, particularly the beliefs that the originate to distribute model was at the root of the crisis and that large numbers of buyers of securitisation notes were unable to decipher the complexity of the instruments they purchased and so did not fully appreciate the risks involved. These assumptions are challenged by the evidence accumulated in the text. Retaining large quantities of collateralized debt obligations on balance sheet, or having to absorb them from sponsored SIVs that were forced to be shut down, proved to be one of the greatest problems for credit entities during the GFC. While the complexity of the financial instruments used was not of itself an impediment for sophisticated professional investors to understand the possible risks involved in the products they purchased, but rather due diligence on the part of buyers was often suspended in a frantic attempt to close deals quickly so as to achieve the best possible price. The thesis is divided into five chapters. The first chapter explains the mechanisms of securitisation and the workings of the shadow banks within the context of the financialisation of the U.S economy. The second chapter traces the origins of the technique of securitisation, from crude tax farming in the Ancient World to the first Private Label Securitisation in the U.S. The third chapter studies the development of derivatives, and the formation of a regulatory framework in Common Law jurisdictions, first in the United Kingdom, and then in the U.S. The fourth chapter explores the ways in which securitisation acted as both a catalyst and a vector for the financial crisis, exposing the structural weaknesses of the U.S economy. The last chapter concentrates on the European response, it focuses on two keys pieces of legislation: Regulation (EU) 2017/2402 which created a general framework for securitisation and a specific framework for simple, transparent and standardised securitisation, and Law 5/2015 which unified the disperse regulation of securitisation in Spain