Multistatic Tracking with the Maximum Likelihood Probabilistic Multi-Hypothesis Tracker

Multistatic sonar tracking is a difficult proposition. The ocean environment typically features very complex propagation conditions, causing low target probabilities of detection and high clutter levels. Additionally, most sonar targets are relatively low speed, which makes it difficult to use Doppler (if available) to separate target returns from clutter returns. The Maximum Likelihood Probabilistic Data Association Tracker (ML-PDA) and the Maximum Likelihood Probabilistic Multi-Hypothesis Tracker (ML-PMHT) --- a similar algorithm to ML-PDA --- can be implemented as effective multistatic trackers. This dissertation will develop a tracking framework for these algorithms. This framework will focus mainly on ML-PMHT, which has an inherent advantage in that its log-likelihood ratio (LLR) has a simple multitarget formulation, which allows it to be implemented as a true multitarget tracker. First, this multitarget LLR will be implemented for ML-PMHT, which will give it superior performance over ML-PDA for instances where multiple targets are closely spaced with similar motion dynamics. Next, the performance of ML-PMHT will be compared when it is applied in Cartesian measurement space and in delay-bearing measurement space, where the measurement covariance is more accurately represented. Following this, a maneuver-model parameterization will be introduced that will allow ML-PDA and ML-PMHT to follow sharply maneuvering targets; their previous straight-line parameterization only allowed them to follow moderately maneuvering targets. Finally, a novel method of determining a tracking threshold for ML-PMHT will be developed by applying extreme value theory to the probabilistic properties of the clutter. This will also be done with target measurements, which will allow the issue of trackability for ML-PMHT to be explored. Probabilistic expressions for the maximum values of the LLR surface caused by both clutter and the target will be developed, which will allow for the determination of target trackability in any given scenario

Bayesian Methods in the Search for MH370

Probability theor

Bayesian Methods in the Search for MH370

Probability theor

Proof-of-Concept

Biometry is an area in great expansion and is considered as possible solution to cases where high authentication parameters are required. Although this area is quite advanced in theoretical terms, using it in practical terms still carries some problems. The systems available still depend on a high cooperation level to achieve acceptable performance levels, which was the backdrop to the development of the following project. By studying the state of the art, we propose the creation of a new and less cooperative biometric system that reaches acceptable performance levels.A constante necessidade de parâmetros mais elevados de segurança, nomeadamente ao nível de autenticação, leva ao estudo biometria como possível solução. Actualmente os mecanismos existentes nesta área tem por base o conhecimento de algo que se sabe ”password” ou algo que se possui ”codigo Pin”. Contudo este tipo de informação é facilmente corrompida ou contornada. Desta forma a biometria é vista como uma solução mais robusta, pois garante que a autenticação seja feita com base em medidas físicas ou compartimentais que definem algo que a pessoa é ou faz (”who you are” ou ”what you do”). Sendo a biometria uma solução bastante promissora na autenticação de indivíduos, é cada vez mais comum o aparecimento de novos sistemas biométricos. Estes sistemas recorrem a medidas físicas ou comportamentais, de forma a possibilitar uma autenticação (reconhecimento) com um grau de certeza bastante considerável. O reconhecimento com base no movimento do corpo humano (gait), feições da face ou padrões estruturais da íris, são alguns exemplos de fontes de informação em que os sistemas actuais se podem basear. Contudo, e apesar de provarem um bom desempenho no papel de agentes de reconhecimento autónomo, ainda estão muito dependentes a nível de cooperação exigida. Tendo isto em conta, e tudo o que já existe no ramo do reconhecimento biometrico, esta área está a dar passos no sentido de tornar os seus métodos o menos cooperativos poss??veis. Possibilitando deste modo alargar os seus objectivos para além da mera autenticação em ambientes controlados, para casos de vigilância e controlo em ambientes não cooperativos (e.g. motins, assaltos, aeroportos). É nesta perspectiva que o seguinte projecto surge. Através do estudo do estado da arte, pretende provar que é possível criar um sistema capaz de agir perante ambientes menos cooperativos, sendo capaz de detectar e reconhecer uma pessoa que se apresente ao seu alcance.O sistema proposto PAIRS (Periocular and Iris Recognition Systema) tal como nome indica, efectua o reconhecimento através de informação extraída da íris e da região periocular (região circundante aos olhos). O sistema é construído com base em quatro etapas: captura de dados, pré-processamento, extração de características e reconhecimento. Na etapa de captura de dados, foi montado um dispositivo de aquisição de imagens com alta resolução com a capacidade de capturar no espectro NIR (Near-Infra-Red). A captura de imagens neste espectro tem como principal linha de conta, o favorecimento do reconhecimento através da íris, visto que a captura de imagens sobre o espectro visível seria mais sensível a variações da luz ambiente. Posteriormente a etapa de pré-processamento implementada, incorpora todos os módulos do sistema responsáveis pela detecção do utilizador, avaliação de qualidade de imagem e segmentação da íris. O modulo de detecção é responsável pelo desencadear de todo o processo, uma vez que esta é responsável pela verificação da exist?ncia de um pessoa em cena. Verificada a sua exist?ncia, são localizadas as regiões de interesse correspondentes ? íris e ao periocular, sendo também verificada a qualidade com que estas foram adquiridas. Concluídas estas etapas, a íris do olho esquerdo é segmentada e normalizada. Posteriormente e com base em vários descritores, é extraída a informação biométrica das regiões de interesse encontradas, e é criado um vector de características biométricas. Por fim, é efectuada a comparação dos dados biometricos recolhidos, com os já armazenados na base de dados, possibilitando a criação de uma lista com os níveis de semelhança em termos biometricos, obtendo assim um resposta final do sistema. Concluída a implementação do sistema, foi adquirido um conjunto de imagens capturadas através do sistema implementado, com a participação de um grupo de voluntários. Este conjunto de imagens permitiu efectuar alguns testes de desempenho, verificar e afinar alguns parâmetros, e proceder a optimização das componentes de extração de características e reconhecimento do sistema. Analisados os resultados foi possível provar que o sistema proposto tem a capacidade de exercer as suas funções perante condições menos cooperativas

Cross-Spectral Full and Partial Face Recognition: Preprocessing, Feature Extraction and Matching

Cross-spectral face recognition remains a challenge in the area of biometrics. The problem arises from some real-world application scenarios such as surveillance at night time or in harsh environments, where traditional face recognition techniques are not suitable or limited due to usage of imagery obtained in the visible light spectrum. This motivates the study conducted in the dissertation which focuses on matching infrared facial images against visible light images. The study outspreads from aspects of face recognition such as preprocessing to feature extraction and to matching.;We address the problem of cross-spectral face recognition by proposing several new operators and algorithms based on advanced concepts such as composite operators, multi-level data fusion, image quality parity, and levels of measurement. To be specific, we experiment and fuse several popular individual operators to construct a higher-performed compound operator named GWLH which exhibits complementary advantages of involved individual operators. We also combine a Gaussian function with LBP, generalized LBP, WLD and/or HOG and modify them into multi-lobe operators with smoothed neighborhood to have a new type of operators named Composite Multi-Lobe Descriptors. We further design a novel operator termed Gabor Multi-Levels of Measurement based on the theory of levels of measurements, which benefits from taking into consideration the complementary edge and feature information at different levels of measurements.;The issue of image quality disparity is also studied in the dissertation due to its common occurrence in cross-spectral face recognition tasks. By bringing the quality of heterogeneous imagery closer to each other, we successfully achieve an improvement in the recognition performance. We further study the problem of cross-spectral recognition using partial face since it is also a common problem in practical usage. We begin with matching heterogeneous periocular regions and generalize the topic by considering all three facial regions defined in both a characteristic way and a mixture way.;In the experiments we employ datasets which include all the sub-bands within the infrared spectrum: near-infrared, short-wave infrared, mid-wave infrared, and long-wave infrared. Different standoff distances varying from short to intermediate and long are considered too. Our methods are compared with other popular or state-of-the-art methods and are proven to be advantageous

Millimeter-Wave Beam Scattering by Edge Turbulence in Magnetically-Confined Plasmas

High-power millimeter-waves (mmw) in the electron cyclotron range of frequencies are extensively used in fusion devices. They have become essential for a number of applications ranging from plasma heating and current drive to core confinement preservation. In ITER, 24 MW of power are planned to be injected through the equatorial launcher to perform bulk plasma heating and current drive; and through the upper-launcher, mainly to stabilize neo-classical tearing mode (NTM) and prevent plasma disruption. The narrowness of the power deposition is a key feature of NTM stabilization and thus a key requirement for the upper-launcher beam in ITER. Recent calculations have estimated that, because of the long path of the upper-launcher beam in ITER, electron density fluctuations associated with the turbulence in the edge of the plasma could be responsible for a broadening of the mmw-beam, possibly deteriorating NTM stabilization efficiency. In this thesis we investigate mmw-scattering by plasma turbulence experimentally and numerically. In the first part of this thesis, millimeter-wave scattering by plasma turbulence is investigated in the simple magnetized toroidal configuration, which turbulence is known to exhibit universal properties of the turbulence present at the edge of tokamaks. Scattering experiments run on both the TORPEX device and the Tokamak à Configuration variable (TCV) reveal that field-aligned elongated structures of enhanced electron density (blobs) are responsible for fluctuations of the transmitted mmw-power. Using conditional sampling on Langmuir probe measurements, we show that blobs can either increase the locally measured mmw-power or decrease it, depending on their location. In the case of the TORPEX experiments, experimental 2D-time imaging of the electron density from the HEXTIP-U array of Langmuir probes is used to run full-wave simulations of the mmw-beam propagation. The full-wave simulations are found in agreement with the experiments and reveal that blobs have a defocusing effect on the mmw-beam in their wake, leading to local changes in the mmw-power. In the second part of this thesis, mmw-wave scattering is investigated in L-mode confined TCV plasmas. A transmission diagnostic is installed to measured the mmw-power from the X3 beam reaching the floor of the vessel after propagation in the plasma. A set of wall-embedded Langmuir probes located in the inner-wall of the TCV vessel is used to perform conditional sampling on the detected mmw-power signal and identify the effect of blobs present in the scrape-off layer on the mmw-transmission. Similar results to those found in TORPEX are observed: Blobs located in the upper-part of the scrape-off layer are responsible for changes in the transmitted power which can be either positive or negative depending on the blob location. The effect of a blob on the mmw-transmission is investigated numerically. Conditional sampling is performed on the turbulence data from GBS to reconstruct the time-resolved 2D evolution of the electron density in the scrape-off layer associated with the propagation of a blob in TCV. The time-evolution of the detected mmw-power associated with the blob propagation from the full-wave simulations is successfully compared to the experiment. The numerical simulations show that negative fluctuations of the electron density preceding the blob focus the mmw-beam and the blob defocuses the mmw-beam, resulting in partial variations of the mmw-power. Finally, a combination of simulations run with WKBeam and experimental measurements demonstrate that the mmw-beam is 50% broader in TCV due to the edge turbulence than the predicted mmw-beam after propagation in a non-turbulent plasma

Ultra-fast YBa2Cu3O7−xYBa_2Cu_3O_{7-x} direct detectors for the THz frequency range

For the analysis and optimization of the picosecond pulsed terahertz radiation generated by electron storage rings or other pulsed sources, ultra-fast detectors are required which are able to resolve picosecond dynamic processes directly in the time domain. In this book, a new direct terahertz detector technology based on the high-temperature superconductor YBa2Cu3O7-x has been developed which opens new routes in the analysis of picosecond time-domain processes with a wide dynamic range

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties

Performance analysis of multimodal biometric fusion

Biometrics is constantly evolving technology which has been widely used in many official and commercial identification applications. In fact in recent years biometric-based authentication techniques received more attention due to increased concerns in security. Most biometric systems that are currently in use typically employ a single biometric trait. Such systems are called unibiometric systems. Despite considerable advances in recent years, there are still challenges in authentication based on a single biometric trait, such as noisy data, restricted degree of freedom, intra-class variability, non-universality, spoof attack and unacceptable error rates. Some of the challenges can be handled by designing a multimodal biometric system. Multimodal biometric systems are those which utilize or are capable of utilizing, more than one physiological or behavioural characteristic for enrolment, verification, or identification. In this thesis, we propose a novel fusion approach at a hybrid level between iris and online signature traits. Online signature and iris authentication techniques have been employed in a range of biometric applications. Besides improving the accuracy, the fusion of both of the biometrics has several advantages such as increasing population coverage, deterring spoofing activities and reducing enrolment failure. In this doctoral dissertation, we make a first attempt to combine online signature and iris biometrics. We principally explore the fusion of iris and online signature biometrics and their potential application as biometric identifiers. To address this issue, investigations is carried out into the relative performance of several statistical data fusion techniques for integrating the information in both unimodal and multimodal biometrics. We compare the results of the multimodal approach with the results of the individual online signature and iris authentication approaches. This dissertation describes research into the feature and decision fusion levels in multimodal biometrics.State of Kuwait – The Public Authority of Applied Education and Trainin

Albumin-Based Drug Delivery Systems

Albumin is playing an increasing role as a versatile, biodegradable drug carrier in clinical theranostics. By applying different techniques, smart drug-delivery systems can be developed from albumin in order to improve drug delivery of different active pharmaceutical ingredients, even small-molecule drugs, peptides or enzymes. Principally, three drug delivery technologies can be distinguished for binding small-molecule or peptide drugs through the charged amino acids, carboxyl, and amino groups of albumin: physical or covalent binding of the drug to albumin through a ligand- or protein-binding group, the fusion of drug with albumin or the encapsulation of drugs into albumin nanoparticles. The accumulation of albumin in inflamed tissues and solid tumours forms the rationale for developing albumin-based drug delivery systems for targeted drug delivery. Besides tumour therapy, albumin-based drug delivery systems can be successfully applied as anti-inflammatory and anti-thrombotic coating for medical devices. The development and optimization of albumin nanoparticles may also be a rational and promising tool for conventional or alternative administration routes in order to improve therapy. This collection provides an overview of the significant scientific research works in this field, which may inspire researchers towards further development and utilization of these smart drug delivery systems