High rate space time code with linear decoding complexity for multiple transmitting antennas

The multipath nature of the wireless channel, results in a superposition of the signals of each path at the receiver. This can lead to either constructive or destructive interference. Strong destructive interference is frequently referred to as deep fade and may result in temporary failure of communication due to the severe drop in the channel\u27s signal-to-noise ratio (SNR). To avoid this situation, signal diversity might be introduced. When having more than one antenna at the transmitter and / or receiver, forming a Multiple-Input Multiple-Output (MIMO) channel, spatial diversity can be employed to overcome the fading problem. Space time block codes (STBC) have been shown to be used well with the MIMO channel. Each type of STBC is designed to optimize a different criteria such as rate and diversity, while other characteristics of the code are its error performance and decoding computational complexity. The Orthogonal STBC (OSTBC) family of codes is known to achieve full diversity as well as very simple implementation of the Maximum Likelihood (ML) decoder. However, it was proven that, with complex symbol constellation one cannot achieve a full rate code when the number of transmitting antennas is larger than two. Quasi OSTBC are codes with full rate but with the penalty of more complex decoding, and in general does not achieve full diversity. In this work, new techniques for OSTBC transmission / decoding are explored, such that a full rate code can be transmitted and decoded with linear complexity. The Row Elimination Method (REM) for OSTBC transmission is introduced, which basically involves the transmission of only part of the original OSTBC codeword, resulting in a full rate code termed Semi-Orthogonal STBC (SSTBC). Novel decoding scheme is presented, such that the SSTBC decoding computational complexity remains linear although the transmitted codeword is not orthogonal anymore. A new OSTBC, that complies with the new scheme\u27s requirements, is presented for any number of transmit antennas. The performance of the new scheme is studied under various settings, such as system with limited feedback and multiple antennas at the receiver. The general decoding techniques presented for STBC, assume perfect channel knowledge at the receiver. It was shown, that the performance of any STBC system is severely degraded due to partial channel state information, results from imperfect channel estimation. To minimize the performance loss, one may lengthen the training sequences used for the channel estimation which, inevitably, results in some rate loss. In addition, complex decoding schemes can be used at the receiver to jointly decode the data while enhancing the channel estimation. It is suggested in this work to apply adaptive techniques to mitigate the performance loss without the penalty of additional rate loss or complex decoding. Namely, the bootstrap algorithm is used to further refine the received signals, resulting in better effective rate and performance in the presence of channel estimation errors. Modified implementations for the bootstrap\u27s weights calculation method are also presented, to improve the convergence rate of the algorithm, as well as to maintain a very low computational burden

Chemometric Approaches for Systems Biology

The present Ph.D. thesis is devoted to study, develop and apply approaches commonly used in chemometrics to the emerging field of systems biology. Existing procedures and new methods are applied to solve research and industrial questions in different multidisciplinary teams. The methodologies developed in this document will enrich the plethora of procedures employed within omic sciences to understand biological organisms and will improve processes in biotechnological industries integrating biological knowledge at different levels and exploiting the software packages derived from the thesis. This dissertation is structured in four parts. The first block describes the framework in which the contributions presented here are based. The objectives of the two research projects related to this thesis are highlighted and the specific topics addressed in this document via conference presentations and research articles are introduced. A comprehensive description of omic sciences and their relationships within the systems biology paradigm is given in this part, jointly with a review of the most applied multivariate methods in chemometrics, on which the novel approaches proposed here are founded. The second part addresses many problems of data understanding within metabolomics, fluxomics, proteomics and genomics. Different alternatives are proposed in this block to understand flux data in steady state conditions. Some are based on applications of multivariate methods previously applied in other chemometrics areas. Others are novel approaches based on a bilinear decomposition using elemental metabolic pathways, from which a GNU licensed toolbox is made freely available for the scientific community. As well, a framework for metabolic data understanding is proposed for non-steady state data, using the same bilinear decomposition proposed for steady state data, but modelling the dynamics of the experiments using novel two and three-way data analysis procedures. Also, the relationships between different omic levels are assessed in this part integrating different sources of information of plant viruses in data fusion models. Finally, an example of interaction between organisms, oranges and fungi, is studied via multivariate image analysis techniques, with future application in food industries. The third block of this thesis is a thoroughly study of different missing data problems related to chemometrics, systems biology and industrial bioprocesses. In the theoretical chapters of this part, new algorithms to obtain multivariate exploratory and regression models in the presence of missing data are proposed, which serve also as preprocessing steps of any other methodology used by practitioners. Regarding applications, this block explores the reconstruction of networks in omic sciences when missing and faulty measurements appear in databases, and how calibration models between near infrared instruments can be transferred, avoiding costs and time-consuming full recalibrations in bioindustries and research laboratories. Finally, another software package, including a graphical user interface, is made freely available for missing data imputation purposes. The last part discusses the relevance of this dissertation for research and biotechnology, including proposals deserving future research.Esta tesis doctoral se centra en el estudio, desarrollo y aplicación de técnicas quimiométricas en el emergente campo de la biología de sistemas. Procedimientos comúnmente utilizados y métodos nuevos se aplican para resolver preguntas de investigación en distintos equipos multidisciplinares, tanto del ámbito académico como del industrial. Las metodologías desarrolladas en este documento enriquecen la plétora de técnicas utilizadas en las ciencias ómicas para entender el funcionamiento de organismos biológicos y mejoran los procesos en la industria biotecnológica, integrando conocimiento biológico a diferentes niveles y explotando los paquetes de software derivados de esta tesis. Esta disertación se estructura en cuatro partes. El primer bloque describe el marco en el cual se articulan las contribuciones aquí presentadas. En él se esbozan los objetivos de los dos proyectos de investigación relacionados con esta tesis. Asimismo, se introducen los temas específicos desarrollados en este documento mediante presentaciones en conferencias y artículos de investigación. En esta parte figura una descripción exhaustiva de las ciencias ómicas y sus interrelaciones en el paradigma de la biología de sistemas, junto con una revisión de los métodos multivariantes más aplicados en quimiometría, que suponen las pilares sobre los que se asientan los nuevos procedimientos aquí propuestos. La segunda parte se centra en resolver problemas dentro de metabolómica, fluxómica, proteómica y genómica a partir del análisis de datos. Para ello se proponen varias alternativas para comprender a grandes rasgos los datos de flujos metabólicos en estado estacionario. Algunas de ellas están basadas en la aplicación de métodos multivariantes propuestos con anterioridad, mientras que otras son técnicas nuevas basadas en descomposiciones bilineales utilizando rutas metabólicas elementales. A partir de éstas se ha desarrollado software de libre acceso para la comunidad científica. A su vez, en esta tesis se propone un marco para analizar datos metabólicos en estado no estacionario. Para ello se adapta el enfoque tradicional para sistemas en estado estacionario, modelando las dinámicas de los experimentos empleando análisis de datos de dos y tres vías. En esta parte de la tesis también se establecen relaciones entre los distintos niveles ómicos, integrando diferentes fuentes de información en modelos de fusión de datos. Finalmente, se estudia la interacción entre organismos, como naranjas y hongos, mediante el análisis multivariante de imágenes, con futuras aplicaciones a la industria alimentaria. El tercer bloque de esta tesis representa un estudio a fondo de diferentes problemas relacionados con datos faltantes en quimiometría, biología de sistemas y en la industria de bioprocesos. En los capítulos más teóricos de esta parte, se proponen nuevos algoritmos para ajustar modelos multivariantes, tanto exploratorios como de regresión, en presencia de datos faltantes. Estos algoritmos sirven además como estrategias de preprocesado de los datos antes del uso de cualquier otro método. Respecto a las aplicaciones, en este bloque se explora la reconstrucción de redes en ciencias ómicas cuando aparecen valores faltantes o atípicos en las bases de datos. Una segunda aplicación de esta parte es la transferencia de modelos de calibración entre instrumentos de infrarrojo cercano, evitando así costosas re-calibraciones en bioindustrias y laboratorios de investigación. Finalmente, se propone un paquete software que incluye una interfaz amigable, disponible de forma gratuita para imputación de datos faltantes. En la última parte, se discuten los aspectos más relevantes de esta tesis para la investigación y la biotecnología, incluyendo líneas futuras de trabajo.Aquesta tesi doctoral es centra en l'estudi, desenvolupament, i aplicació de tècniques quimiomètriques en l'emergent camp de la biologia de sistemes. Procediments comúnment utilizats i mètodes nous s'apliquen per a resoldre preguntes d'investigació en diferents equips multidisciplinars, tant en l'àmbit acadèmic com en l'industrial. Les metodologies desenvolupades en aquest document enriquixen la plétora de tècniques utilitzades en les ciències òmiques per a entendre el funcionament d'organismes biològics i milloren els processos en la indústria biotecnològica, integrant coneixement biològic a distints nivells i explotant els paquets de software derivats d'aquesta tesi. Aquesta dissertació s'estructura en quatre parts. El primer bloc descriu el marc en el qual s'articulen les contribucions ací presentades. En ell s'esbossen els objectius dels dos projectes d'investigació relacionats amb aquesta tesi. Així mateix, s'introduixen els temes específics desenvolupats en aquest document mitjançant presentacions en conferències i articles d'investigació. En aquesta part figura una descripació exhaustiva de les ciències òmiques i les seues interrelacions en el paradigma de la biologia de sistemes, junt amb una revisió dels mètodes multivariants més aplicats en quimiometria, que supossen els pilars sobre els quals s'assenten els nous procediments ací proposats. La segona part es centra en resoldre problemes dins de la metabolòmica, fluxòmica, proteòmica i genòmica a partir de l'anàlisi de dades. Per a això es proposen diverses alternatives per a compendre a grans trets les dades de fluxos metabòlics en estat estacionari. Algunes d'elles estàn basades en l'aplicació de mètodes multivariants propostos amb anterioritat, mentre que altres són tècniques noves basades en descomposicions bilineals utilizant rutes metabòliques elementals. A partir d'aquestes s'ha desenvolupat software de lliure accés per a la comunitat científica. Al seu torn, en aquesta tesi es proposa un marc per a analitzar dades metabòliques en estat no estacionari. Per a això s'adapta l'enfocament tradicional per a sistemes en estat estacionari, modelant les dinàmiques dels experiments utilizant anàlisi de dades de dues i tres vies. En aquesta part de la tesi també s'establixen relacions entre els distints nivells òmics, integrant diferents fonts d'informació en models de fusió de dades. Finalment, s'estudia la interacció entre organismes, com taronges i fongs, mitjançant l'anàlisi multivariant d'imatges, amb futures aplicacions a la indústria alimentària. El tercer bloc d'aquesta tesi representa un estudi a fons de diferents problemes relacionats amb dades faltants en quimiometria, biologia de sistemes i en la indústria de bioprocessos. En els capítols més teòrics d'aquesta part, es proposen nous algoritmes per a ajustar models multivariants, tant exploratoris com de regressió, en presencia de dades faltants. Aquests algoritmes servixen ademés com a estratègies de preprocessat de dades abans de l'ús de qualsevol altre mètode. Respecte a les aplicacions, en aquest bloc s'explora la reconstrucció de xarxes en ciències òmiques quan apareixen valors faltants o atípics en les bases de dades. Una segona aplicació d'aquesta part es la transferència de models de calibració entre instruments d'infrarroig proper, evitant així costoses re-calibracions en bioindústries i laboratoris d'investigació. Finalment, es proposa un paquet software que inclou una interfície amigable, disponible de forma gratuïta per a imputació de dades faltants. En l'última part, es discutixen els aspectes més rellevants d'aquesta tesi per a la investigació i la biotecnologia, incloent línies futures de treball.Folch Fortuny, A. (2016). Chemometric Approaches for Systems Biology [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/77148TESISPremios Extraordinarios de tesis doctorale

Automatic image annotation and object detection

We live in the midst of the information era, during which organising and indexing information more effectively is a matter of essential importance. With the fast development of digital imagery, how to search images - a rich form of information - more efficiently by their content has become one of the biggest challenges. Content-based image retrieval (CBIR) has been the traditional and dominant technique for searching images for decades. However, not until recently have researchers started to realise some vital problems existing in CBIR systems. One of the most important is perhaps what people call the \textit{semantic gap}, which refers to the gap between the information that can be extracted from images and the interpretation of the images for humans. As an attempt to bridge the semantic gap, automatic image annotation has been gaining more and more attentions in recent years. This thesis aims to explore a number of different approaches to automatic image annotation and some related issues. It begins with an introduction into different techniques for image description, which forms the foundation of the research on image auto-annotation. The thesis then goes on to give an in-depth examination of some of the quality issues of the data-set used for evaluating auto-annotation systems. A series of approaches to auto-annotation are presented in the follow-up chapters. Firstly, we describe an approach that incorporates the salient based image representation into a statistical model for better annotation performance. Secondly, we explore the use of non-negative matrix factorisation (NMF), a matrix decomposition tehcnique, for two tasks; object class detection and automatic annotation of images. The results imply that NMF is a promising sub-space technique for these purposes. Finally, we propose a model named the image based feature space (IBFS) model for linking image regions and keywords, and for image auto-annotation. Both image regions and keywords are mapped into the same space in which their relationships can be measured. The idea of multiple segmentations is then implemented in the model, and better results are achieved than using a single segmentation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Polymorph selection in continuous, reactive, rate-based, precipitation systems

Many materials are capable of organizing into multiple distinct solid phases, each exhibiting a unique set of material properties (e.g., mechanical, optical, electronic, catalytic, etc.). This material property diversity implies that a specific solid form or structure is typically preferred for a specific application. Thus, directing and controlling solid form during crystallization processes is a fundamental solid state engineering challenge. Here, for the first time, a general procedure is presented for designing continuous crystallizers that produce polymorphically pure crystal distributions of a preferred polymorph regardless of that polymorph's relative thermodynamic stability. The design rules were generated by developing and analyzing a multi-polymorph mixed suspension mixed product removal precipitator model, and they have been corroborated both by experimental data generated in our lab and by all of the applicable data in the published literature. These rules were developed to build understanding and aid in the process design of two sustainable energy technologies: carbon capture and utilization as structural materials (CCUSM) and methane pyrolysis (MP). Studying these processes also required the development of new models for calculating interphase mass transport in concentrated, electrolytic, reacting solutions and for describing the reactive transport that occurs in methane pyrolysis membrane reactors. The development and analysis of these models and a thermodynamic minimum energetic cost assessment of a wider set of sustainable energy technologies are also included in the dissertation

Convex reconstruction from structured measurements

Convex signal reconstruction is the art of solving ill-posed inverse problems via convex optimization. It is applicable to a great number of problems from engineering, signal analysis, quantum mechanics and many more. The most prominent example is compressed sensing, where one aims at reconstructing sparse vectors from an under-determined set of linear measurements. In many cases, one can prove rigorous performance guarantees for these convex algorithms. The combination of practical importance and theoretical tractability has directed a significant amount of attention to this young field of applied mathematics. However, rigorous proofs are usually only available for certain "generic cases"---for instance situations, where all measurements are represented by random Gaussian vectors. The focus of this thesis is to overcome this drawback by devising mathematical proof techniques can be applied to more "structured" measurements. Here, structure can have various meanings. E.g. it could refer to the type of measurements that occur in a given concrete application. Or, more abstractly, structure in the sense that a measurement ensemble is small and exhibits rich geometric features. The main focus of this thesis is phase retrieval: The problem of inferring phase information from amplitude measurements. This task is ubiquitous in, for instance, in crystallography, astronomy and diffraction imaging. Throughout this project, a series of increasingly better convex reconstruction guarantees have been established. On the one hand, we improved results for certain measurement models that mimic typical experimental setups in diffraction imaging. On the other hand, we identified spherical t-designs as a general purpose tool for the derandomization of data recovery schemes. Loosely speaking, a t-design is a finite configuration of vectors that is "evenly distributed" in the sense that it reproduces the first 2t moments of the uniform measure. Such configurations have been studied, for instance, in algebraic combinatorics, coding theory, and quantum information. We have shown that already spherical 4-designs allow for proving close-to-optimal convex reconstruction guarantees for phase retrieval. The success of this program depends on explicit constructions of spherical t-designs. In this regard, we have studied the design properties of stabilizer states. These are configurations of vectors that feature prominently in quantum information theory. Mathematically, they can be related to objects in discrete symplectic vector spaces---a structure we use heavily. We have shown that these vectors form a spherical 3-design and are, in some sense, close to a spherical 4-design. Putting these efforts together, we establish tight bounds on phase retrieval from stabilizer measurements. While working on the derandomization of phase retrieval, I obtained a number of results on other convex signal reconstruction problems. These include compressed sensing from anisotropic measurements, non-negative compressed sensing in the presence of noise and identifying improved convex regularizers for low rank matrix reconstruction. Going even further, the mathematical methods I used to tackle ill-posed inverse problems can be applied to a plethora of problems from quantum information theory. In particular, the causal structure behind Bell inequalities, new ways to compare experiments to fault-tolerance thresholds in quantum error correction, a novel benchmark for quantum state tomography via Bayesian estimation, and the task of distinguishing quantum states

On Cohomological Algebras in Supersymmetric Quantum Field Theories

In this thesis we compute certain supersymmetric subsectors of the algebra of observables in some QFTs and demonstrate an application of such computation in checking an instance of Holographic duality. Computing the algebra of observables beyond perturbative approximation in weakly coupled field theories is far from a tractable problem. In some special, yet interesting large classes of supersymmetric theories, supersymmetry can be used to extract exact nonperturbative information about certain subsets of observables. This is an old idea which we advance in this thesis by introducing new techniques of computations, computing certain observalbes for the first time, and reproducing earlier results about some other observables. We also propose a new toy model of holographic duality involving topological/holomorphic theories, demonstrating the power of exact computations in supersymmetric subsectors. To be more specific, the subject of this thesis includes the following: 1. Computing the algebra of chiral and twisted chiral operators in 2d N=(2,2) theories -- while these algebras were previously known, we demonstrate how they can be computed using relatively modern techniques of supersymmetric localization. 2. Computing the chiral rings of 4d N=2 SCFTs -- we compute this algebra for the first time. We use the same method of supersymmetric localization that we use in the 2d case. 3. Computing the algebra of operators on a defect in the topological 2d BF theory, along with its holographic dual. This is a new toy model of holographic duality set in the world of 6d topological string theory. We also argue that this setup is in fact a certain supersymmetric subsector of the holographic duality involving 4d N=4 SYM theory and its 10d supergravity dual -- both involving some defects. In order to be able to discuss these different theories in different dimensions with different symmetries without sounding disparate and ad hoc, we employ the language of cohomological algebra. Since this is perhaps not a language most commonly used in the standard physics literature, we would like to emphasize that this is not a novel idea, it is merely a convenient thematic and linguistic umbrella that covers all the topics of this thesis. In the BV formulation of a QFT, the algebra of observables is presented as the cohomology algebra of a certain complex consisting of fields and anti-fields. In this language restriction to supersymmetric subsectors correspond to modifying the BV differential by the addition of the relevant supersymmetry generator. We simply refer to this modification as reduction to cohomology (with respect to the choice of supersymmetry)

Surface wave interferometry

This thesis concerns the application of seismic interferometry to surface waves. Seismic interferometry is the process by which the wavefield between two recording locations is estimated, resulting in new recordings at one location as if a source had been placed at the other. Thus, in surface-wave interferometry, surface waves propagating between two receiver locations are estimated as if one receiver had recorded the response due to a source of surface-wave energy at the other receiver. In global and engineering seismology new surface-wave responses can allow for imaging of the subsurface, and in exploration seismology it has been proposed that these new surface-wave responses can allow for the prediction and removal of socalled ground-roll (surface waves that are treated as noise). This thesis presents a detailed analysis of surface-wave interferometry: using a combination of modelling studies, real-data studies, and theoretical analyses the processes involved in the application of interferometry to complex (both multi-mode and scattered) surface waves are revealed. These analyses identify why surface waves are often dominant in the application of interferometry, where errors may be introduced in the application of surface-wave interferometry, and how interferometry may be processed in such a way as to minimise those (and other) errors. This allows for the proposal of new data-processing strategies in the application of seismic interferometry to surface waves, potentially resulting in improved surface-wave estimates. Much of the work in this thesis focuses on the use of seismic interferometry to predict and subtract surface waves in land-seismic exploration surveys. Using insights from the presented analyses it is shown that seismic surface waves can be successfully predicted and removed from land-seismic data using an interferometric approach. However, the work in this thesis is not only limited to applications in exploration seismology. In addition to the ground-roll removal method, improved estimates of higher-mode and scattered surfaces waves may allow for more advanced imaging algorithms to be used in conjunction with seismic interferometry. Also, as a consequence of the analysis presented a Generalized Optical Theorem for Surface Waves is derived. This highlights a link between seismic interferometry and the optical theorem and may allow for further application of optical theorems in seismology