Now showing items 229-248 of 345

    Ocean monitoring using L-Band microwave radiometry and GNSS-R 

    Valencia Domènech, Enric (Date of defense: 2012-10-17)

    The knowledge of sea surface salinity (SSS) is a key issue to understand and monitor the Earth¿s water cycle. Accurate and systematic measurement of SSS was not possible until the ESA¿s Soil Moisture and Ocean Salinity ...

    Ocean surface currents reconstruction from microwave radiometers measurements 

    González Haro, Cristina (Date of defense: 2015-05-22)

    Ocean currents are a key component to understanding many oceanic and climatic phenomena and knowledge of them is crucial for both navigation and operational applications. Therefore, a key problem in oceanography is the ...

    On the design of high-efficiency RF Doherty power amplifiers 

    Yahyavi, Mehran (Date of defense: 2016-03-18)

    Power amplifiers (PAs) are one of the most crucial elements in wireless standards becasue they are the most power hungry subsystems. These elements have to face an important issue, which is the power efficiency, a fact ...

    On the design of microwave radiometers with digital beamforming and polarization synthesis for earth observation. 

    Bosch Lluis, Xavier (Date of defense: 2011-03-30)

    Actualment, la comunitat científica ja disposa de les primeres mesures radiomètriques a banda L, polarimètriques i multi-angulars fetes de l’espai. Això és gràcies al recent llançament de la missió de la Eurepean Space ...

    On the detection of ionospheric waves, relationship with earthquakes and tsunamis 

    Yang, Heng, 1985- (Date of defense: 2019-06-11)

    The research of this thesis addresses the detection and characterization of ionospheric waves and its application to traveling ionospheric disturbances (TIDs) induced by the natural events, such as earthquakes and tsunamis. ...

    On the resource abstraction, partitioning and composition for virtual GMPLS-controlled multi-layer optical networks 

    Vilalta Cañellas, Ricard (Date of defense: 2013-12-03)

    Virtual optical networking supports the dynamic provisioning of dedicated networks over the same network infrastructure, which has received a lot of attention by network providers. The stringent network requirements (e.g., ...

    Opportunistic communications in large uncoordinated networks 

    Borràs Pino, Jordi (Date of defense: 2023-01-25)

    (English) The increase of wireless devices offering high data rate services limits the coexistence of wireless systems sharing the same resources in a given geographical area because of inter-system interference. Therefore, ...

    Optical solitons in quadratic nonlinear media and applications to all-optical switching and routing devices 

    Santos Blanco, María Concepción (Date of defense: 1998-03-02)

    Esta tesis constituye un estudio detallado y exhaustivo de las propiedades de una variedad específica de ondas ópticas solitarias. Observadas experimentalmente por primera vez en 1995, estas ondas estan formadas por un ...

    Optimal sizing and operation planning of microgrids and operation analysis of charging stations for electric vehicles 

    Zenginis, Ioannis (Date of defense: 2018-12-20)

    Energy and transportation sectors are going through major changes as a result of technological advances, depletion of fossil fuels and climate change. With regard to the energy sector, the future smart grid is expected to ...

    Optimization and generalization of lifting schemes: application to lossless image compression 

    Solé Rojals, Joel (Date of defense: 2006-06-29)

    This Ph.D. thesis dissertation addresses multi-resolution image decomposition, a key issue in signal processing that in recent years has contributed to the emergence of the JPEG2000 image compression standard. JPEG2000 ...

    Optimization of emerging extended FTTH WDM/TDM PONs and financial overall assessment 

    Chatzi, Sotiria (Date of defense: 2013-11-26)

    Optical access technology has experienced a boost in the last years, thanks to the continuously migrating multimedia services that are offered over the internet. Though the technologies used for deploying Fiber-To-The-x ...

    Optimization of positioning capabilities in wireless sensor networks : from power efficiency to medium access 

    Moragrega Estrany, Anna (Date of defense: 2016-02-04)

    In Wireless Sensor Networks (WSN), the ability of sensor nodes to know its position is an enabler for a wide variety of applications for monitoring, control, and automation. Often, sensor data is meaningful only if its ...

    Optimization of Segmentation-Based Video Sequence Coding Techniques. Application to content based functionalities 

    Morros Rubió, Josep Ramon (Date of defense: 2004-12-23)

    En aquest treball s'estudia el problema de la compressió de video utilitzant funcionalitats basades en el contingut en el marc teòric dels sistemes de codificació de seqüències de video basats en regions. Es tracten ...

    Optimized content caching strategies for multi-access edge computing (MEC)-assisted future cellular networks 

    Ayenew, Tadege Mihretu (Date of defense: 2023-11-21)

    (English) Handling the tsunami of multimedia content is a big challenge for heterogeneous cellular networks. Serving large volumes of content from the central system to end-users, through a bandwidth-limited network, at ...

    Orbital differential SAR interferometry with polarimetric data 

    Monells Miralles, Daniel (Date of defense: 2017-01-18)

    Space-borne Synthetic Aperture Radar (SAR) systems have demonstrated great effectiveness to survey wide areas, independently of the weather conditions and the day/night cycle. One of the most exploited applications is ...

    Parallel scalability of face detection in heterogeneous multithreaded architectures 

    Oro García, David (Date of defense: 2020-11-17)

    Recently, facial recognition systems have become extremely popular and deployments of this technology are now ubiquitous. Applications ranging from access control to automated surveillance of video feeds rely on facial ...

    Parametric region-based foreround segmentation in planar and multi-view sequences 

    Gallego Vila, Jaime (Date of defense: 2013-10-14)

    Foreground segmentation in video sequences is an important area of the image processing that attracts great interest among the scientist community, since it makes possible the detection of the objects that appear in the ...

    Part-based object retrieval with binary partition trees 

    Giró i Nieto, Xavier (Date of defense: 2012-05-31)

    This thesis addresses the problem of visual object retrieval, where a user formulates a query to an image database by providing one or multiple examples of an object of interest. The presented techniques aim both at finding ...

    Pau-synthetic aperture: a new instrument to test potential improvements for future interferometric radiometers 

    Ramos Pérez, Isaac (Date of defense: 2012-02-27)

    The Soil Moisture and Ocean Salinity (SMOS) mission is an Earth Explorer Opportunity mission from the European Space Agency (ESA). It was a direct response to the global observations of soil moisture and ocean salinity. ...

    Perfomance limits of spatial multiplexing mimo systems 

    García Ordoñez, Luis (Date of defense: 2009-05-06)

    Los canales multiple-input multiple-output (MIMO) proporcionan una forma abstracta y general de modelar un gran número de sistemas de comunicaciones. Los canales MIMO inalámbricos, en concreto, han despertado un gran interés ...