4 resultados para contention

em Universidad Politécnica de Madrid


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Nowadays, one of the urgent issues regarding global climate change is to discuss the future of the second period of the Kyoto Protocol. However, the divergence of views and opinions among parties in the last Conference of the Parties of the United Nations Framework Convention on Climate Change, held in Durban in December 2011, is still large. One of the bones of contention is whether the emerging developing countries, like China, should make commitments and legally bind themselves to a Green House Gas (GHG) reduction target in near future. As the largest GHG emitting country, China and its energy and climate policies will play an important role in global climate change and will also significantly influence the other countries? policies and the global climate negotiation. In this paper, we review the current differences among parties in the Durban Conference, and we analyze the recent situation, barriers, and future policies in China. Finally we highlight the impact and potential effect of Clean Development Mechanisms in avoiding China?s barriers regarding climate change. Results show that China is making a great effort to mitigate climate change by establishing and reforming its energy and climate policies in order to achieve a low-carbon development. At the same time, more innovation and international collaboration is needed in China to achieve this goal.

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El presente trabajo de tesis doctoral tiene por finalidad demostrar que las decisiones de financiacin y de inversin inmobiliaria en Espaa influyen de manera determinante en la configuracin del proceso urbanstico y arquitectnico. Este planteamiento inicial obliga a formular las siguientes cuestiones: - En una primera fase, la situacin en Espaa del sector inmobiliario y su relacin con el sector financiero en el contexto de la actual crisis financiera, iniciada en el ao 2008. - Los mtodos de anlisis y seleccin de inversiones y su aplicacin a los proyectos de inversin en funcin de la naturaleza de los activos inmobiliarios. - La valoracin inmobiliaria para determinadas entidades financieras. - Caractersticas de la gestin financiera empresarial y de las empresas inmobiliarias. - El origen de fondos para financiar el proceso urbanstico y arquitectnico mediante las instituciones de inversin colectiva inmobiliaria y el mercado inmobiliario. - La regulacin actual en Espaa, a nivel estatal, del suelo como materia prima del sector inmobiliario. - La edificacin residencial y el mercado inmobiliario en el actual contexto econmico. - La posibilidad de crear en Espaa un mercado de derivados basado en activos inmobiliarios. - Cmo repercute la actividad econmica, a travs de la inversin y la financiacin, en los activos inmobiliarios, en el urbanismo y la arquitectura. Las cuestiones precedentes se resuelven de forma sistemtica y metodolgica en esta tesis doctoral estructurada en tres grandes bloques (inversin, financiacin y repercusiones en el urbanismo y la arquitectura), obteniendo una serie de respuestas reflejadas en el desarrollo del presente trabajo que se sintetizan en las siguientes lneas: - La actual crisis financiera iniciada en el ao 2008 ha provocado en Espaa el colapso del sector inmobiliario y una nueva concepcin en la naturaleza de los activos inmobiliarios. El sector inmobiliario trae causa del sector financiero, en especial del crdito bancario. - Dependencia y vinculacin del sector inmobiliario espaol de la poltica monetaria europea: la incorporacin de Espaa a la moneda nica transforma por completo el sector inmobiliario espaol. - Los mtodos de anlisis y seleccin de inversiones se conforman como instrumentos relevantes que nos permiten jerarquizar nuestros proyectos. No obstante, presentan una serie de limitaciones y dificultades de aplicacin prctica, por lo que no deben considerarse como herramientas que nos aporten una nica solucin irrefutable. - La valoracin de activos inmobiliarios se constituye en un pilar bsico que fundamenta la correcta aplicacin de los fondos. - La inversin en activos inmobiliarios puede realizarse de forma directa o indirecta. En este ltimo supuesto, con una influencia relevante de las innovaciones financieras surgidas en los ltimos aos. - Las instituciones de inversin colectiva y el mercado hipotecario constituyen instituciones fundamentales capaces de captar importantes cantidades de fondos que impulsan y financian el proceso urbanstico y arquitectnico. - El complejo y cambiante sistema jurdico espaol en materia de suelo, dificulta la implementacin de los procesos urbansticos y arquitectnicos. - Tras la crisis financiera de 2008, los activos inmobiliarios tienen un comportamiento similar a otros activos en cuanto a subidas y bajadas de precios. En el actual sistema econmico, la especulacin forma parte inherente a la naturaleza de los activos inmobiliarios. - Desde una perspectiva terica, existe la posibilidad de crear un mercado de derivados que tenga como subyacente activos de naturaleza inmobiliaria. - Sin actividad econmica, el proceso urbanstico y arquitectnico carecer finalmente de sentido y tender a desaparecer. No obstante, son las innovaciones tecnolgicas, a nivel de producto y proceso, las principales causantes del impulso de la actividad econmica. - A pesar de lo expresado en los documentos urbansticos internacionales, la transformacin del urbanismo y la arquitectura dependen principalmente de la actividad econmica y la tecnologa. En un segundo nivel, la inversin y la financiacin condicionan y definen el urbanismo y la arquitectura, incluso a nivel de proyecto si se pretende su materializacin. En base al desarrollo previo, el objetivo fundamental de esta tesis doctoral ha sido demostrar que las decisiones de financiacin y de inversin tienen una importancia capital y determinan la configuracin de los activos inmobiliario, del urbanismo y la arquitectura, por lo que deben ser tenidas en cuenta no slo en su materializacin sino incluso en la propia concepcin del proceso creativo. ABSTRACT The present dissertation aims to show that real estate financing and investment decisions in Spain play a predominant role in structuring urban development and architectural solutions. The issues addressed to support that contention include: - As a preliminary study, the situation of the real estate industry in Spain and its relationship to the financial sector in the context of the 2008 financial crisis. - The methods used to analyse and select investments and their application to investment projects, by type of real estate asset. - Appraisal of certain financial institutions real estate asset holdings. - Characteristics of financial institution and real estate company corporate management. - Sourcing funds for financing urban development and architecture through real estate investment trusts and the real estate market. - Present nation-wide regulations on landed property in Spain as a raw material for the real estate industry. - Residential building construction and the real estate market in the present economic context. - The possibility of creating a real estate asset-based derivatives market in Spain - The impact of economic activity, through investment and financing, on real estate assets, urban development and architecture. The aforementioned issues are addressed systematically and methodically in this dissertation, which is divided into three major units: investment, financing, and impact on urban development and architecture. The conclusions drawn are summarised below. - The financial crisis that began in 2008 has induced the collapse of the Spanish real estate industry and spawned a new perception of the nature of real estate assets. The real estate industry is dependent upon the financial sector, in particular on bank loans. - The Spanish real estate industry also depends on and is related to European monetary policy: Spains adherence to the single currency ushered in a thorough overhaul of its real estate industry. - Investment analysis and selection methods constitute highly suitable tools for project evaluation and ranking. Nonetheless, inasmuch as their practical implementation is subject to a series of limitations and difficulties, they should not be thought able to deliver a single irrefutable solution. - Real estate asset appraisal is a mainstay to the rightful application of funds. - Real estate asset investments can be made directly or indirectly. The latter approach is heavily influenced by the financial innovations forthcoming in recent years. - Investment trusts and the mortgage market are key institutions able to raise substantial funding, thereby driving and financing urban development and architecture. - Spains complex and changing legal provisions on land management are an obstacle to urban development and architecture. - Since the 2008 crisis, real estate assets have behaved much like other assets in terms of rising and falling prices. In the present economic context, speculation is indivisible from real estate assets. - Theoretically speaking, a derivatives market with real estate holdings as the underlying assets lies within the realm of possibility. - In the absence of economic activity, urban development and architecture are senseless pursuits and tend to disappear. Technological innovation in products and processes are the main drivers of economic activity. - Despite the opinion expressed in international papers on the subject, the transformation of urban development and architecture depend primarily on economic activity and technology. In a second dimension, investment and financing condition and define urban development and architecture, even at the design level for projects aspiring to actual construction. Pursuant to the foregoing, the primary aim of this dissertation is to show that financial and investment decisions are of cardinal importance and determine the structure of real estate assets, urban development and architecture. They must consequently be borne in mind not only in connection with implementation, but also with conceptual design and the creative process itself. I

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According to Self-determination Theory (SDT), there are only three psychological needs - competence, autonomy and relatedness - truly fundamental and essential for human being?s health and well-being, which can be satisfied by individuals while engaging in a wide variety of behaviors that may differ among individuals and be differentially manifest in different cultures. However, a number of questions have been raised about SDT?s contention that there are only those three basic psychological needs. The present study discusses the possibility that the security need should be considered as a basic need and its relation to the accepted three basic psychological needs. Using the Cultural Theory framework the degree of satisfaction of the basic needs, depending on the type of culture, is also presented.

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Esta tesis se desarrolla dentro del marco de las comunicaciones satelitales en el innovador campo de los pequeos satlites tambin llamados nanosatlites o cubesats, llamados as por su forma cubica. Estos nanosatlites se caracterizan por su bajo costo debido a que usan componentes comerciales llamados COTS (commercial off-the-shelf) y su pequeo tamao como los Cubesats 1U (10cm*10 cm*10 cm) con masa aproximada a 1 kg. Este trabajo de tesis tiene como base una iniciativa propuesta por el autor de la tesis para poner en rbita el primer satlite peruano en mi pas llamado chasqui I, actualmente puesto en rbita desde la Estacin Espacial Internacional. La experiencia de este trabajo de investigacin me llevo a proponer una constelacin de pequeos satlites llamada Waposat para dar servicio de monitoreo de sensores de calidad de agua a nivel global, escenario que es usado en esta tesis. Es ente entorno y dadas las caractersticas limitadas de los pequeos satlites, tanto en potencia como en velocidad de datos, es que propongo investigar una nueva arquitectura de comunicaciones que permita resolver en forma ptima la problemtica planteada por los nanosatlites en rbita LEO debido a su carcter disruptivo en sus comunicaciones poniendo nfasis en las capas de enlace y aplicacin. Esta tesis presenta y evala una nueva arquitectura de comunicaciones para proveer servicio a una red de sensores terrestres usando una solucin basada en DTN (Delay/Disruption Tolerant Networking) para comunicaciones espaciales. Adicionalmente, propongo un nuevo protocolo de acceso mltiple que usa una extensin del protocolo ALOHA no ranurado, el cual toma en cuenta la prioridad del trafico del Gateway (ALOHAGP) con un mecanismo de contienda adaptativo. Utiliza la realimentacin del satlite para implementar el control de la congestin y adapta dinmicamente el rendimiento efectivo del canal de una manera ptima. Asumimos un modelo de poblacin de sensores finito y una condicin de trfico saturado en el que cada sensor tiene siempre tramas que transmitir. El desempeo de la red se evalu en trminos de rendimiento efectivo, retardo y la equidad del sistema. Adems, se ha definido una capa de convergencia DTN (ALOHAGP-CL) como un subconjunto del estndar TCP-CL (Transmission Control Protocol-Convergency Layer). Esta tesis muestra que ALOHAGP/CL soporta adecuadamente el escenario DTN propuesto, sobre todo cuando se utiliza la fragmentacin reactiva. Finalmente, esta tesis investiga una transferencia ptima de mensajes DTN (Bundles) utilizando estrategias de fragmentacin proactivas para dar servicio a una red de sensores terrestres utilizando un enlace de comunicaciones satelitales que utiliza el mecanismo de acceso mltiple con prioridad en el trfico de enlace descendente (ALOHAGP). El rendimiento efectivo ha sido optimizado mediante la adaptacin de los parmetros del protocolo como una funcin del nmero actual de los sensores activos recibidos desde el satlite. Tambin, actualmente no existe un mtodo para advertir o negociar el tamao mximo de un bundle que puede ser aceptado por un agente DTN bundle en las comunicaciones por satlite tanto para el almacenamiento y la entrega, por lo que los bundles que son demasiado grandes son eliminados o demasiado pequeos son ineficientes. He caracterizado este tipo de escenario obteniendo una distribucin de probabilidad de la llegada de tramas al nanosatlite as como una distribucin de probabilidad del tiempo de visibilidad del nanosatlite, los cuales proveen una fragmentacin proactiva ptima de los DTN bundles. He encontrado que el rendimiento efectivo (goodput) de la fragmentacin proactiva alcanza un valor ligeramente inferior al de la fragmentacin reactiva. Esta contribucin permite utilizar la fragmentacin activa de forma ptima con todas sus ventajas tales como permitir implantar el modelo de seguridad de DTN y la simplicidad al implementarlo en equipos con muchas limitaciones de CPU y memoria. La implementacin de estas contribuciones se han contemplado inicialmente como parte de la carga til del nanosatlite QBito, que forma parte de la constelacin de 50 nanosatlites que se est llevando a cabo dentro del proyecto QB50. ABSTRACT This thesis is developed within the framework of satellite communications in the innovative field of small satellites also known as nanosatellites (<10 kg) or CubeSats, so called from their cubic form. These nanosatellites are characterized by their low cost because they use commercial components called COTS (commercial off-the-shelf), and their small size and mass, such as 1U Cubesats (10cm * 10cm * 10cm) with approximately 1 kg mass. This thesis is based on a proposal made by the author of the thesis to put into orbit the first Peruvian satellite in his country called Chasqui I, which was successfully launched into orbit from the International Space Station in 2014. The experience of this research work led me to propose a constellation of small satellites named Waposat to provide water quality monitoring sensors worldwide, scenario that is used in this thesis. In this scenario and given the limited features of nanosatellites, both power and data rate, I propose to investigate a new communications architecture that allows solving in an optimal manner the problems of nanosatellites in orbit LEO due to the disruptive nature of their communications by putting emphasis on the link and application layers. This thesis presents and evaluates a new communications architecture to provide services to terrestrial sensor networks using a space Delay/Disruption Tolerant Networking (DTN) based solution. In addition, I propose a new multiple access mechanism protocol based on extended unslotted ALOHA that takes into account the priority of gateway traffic, which we call ALOHA multiple access with gateway priority (ALOHAGP) with an adaptive contention mechanism. It uses satellite feedback to implement the congestion control, and to dynamically adapt the channel effective throughput in an optimal way. We assume a finite sensor population model and a saturated traffic condition where every sensor always has frames to transmit. The performance was evaluated in terms of effective throughput, delay and system fairness. In addition, a DTN convergence layer (ALOHAGP-CL) has been defined as a subset of the standard TCP-CL (Transmission Control Protocol-Convergence Layer). This thesis reveals that ALOHAGP/CL adequately supports the proposed DTN scenario, mainly when reactive fragmentation is used. Finally, this thesis investigates an optimal DTN message (bundles) transfer using proactive fragmentation strategies to give service to a ground sensor network using a nanosatellite communications link which uses a multi-access mechanism with priority in downlink traffic (ALOHAGP). The effective throughput has been optimized by adapting the protocol parameters as a function of the current number of active sensors received from satellite. Also, there is currently no method for advertising or negotiating the maximum size of a bundle which can be accepted by a bundle agent in satellite communications for storage and delivery, so that bundles which are too large can be dropped or which are too small are inefficient. We have characterized this kind of scenario obtaining a probability distribution for frame arrivals to nanosatellite and visibility time distribution that provide an optimal proactive fragmentation of DTN bundles. We have found that the proactive effective throughput (goodput) reaches a value slightly lower than reactive fragmentation approach. This contribution allows to use the proactive fragmentation optimally with all its advantages such as the incorporation of the security model of DTN and simplicity in protocol implementation for computers with many CPU and memory limitations. The implementation of these contributions was initially contemplated as part of the payload of the nanosatellite QBito, which is part of the constellation of 50 nanosatellites envisaged under the QB50 project.