Sparse 3D Point-cloud Map Upsampling and Noise Removal as a vSLAM Post-processing Step: Experimental Evaluation

The monocular vision-based simultaneous localization and mapping (vSLAM) is one of the most challenging problem in mobile robotics and computer vision. In this work we study the post-processing techniques applied to sparse 3D point-cloud maps, obtained by feature-based vSLAM algorithms. Map post-processing is split into 2 major steps: 1) noise and outlier removal and 2) upsampling. We evaluate different combinations of known algorithms for outlier removing and upsampling on datasets of real indoor and outdoor environments and identify the most promising combination. We further use it to convert a point-cloud map, obtained by the real UAV performing indoor flight to 3D voxel grid (octo-map) potentially suitable for path planning.Comment: 10 pages, 4 figures, camera-ready version of paper for "The 3rd International Conference on Interactive Collaborative Robotics (ICR 2018)

Connectionist perspectives on language learning, representation and processing.

The field of formal linguistics was founded on the premise that language is mentally represented as a deterministic symbolic grammar. While this approach has captured many important characteristics of the world\u27s languages, it has also led to a tendency to focus theoretical questions on the correct formalization of grammatical rules while also de-emphasizing the role of learning and statistics in language development and processing. In this review we present a different approach to language research that has emerged from the parallel distributed processing or \u27connectionist\u27 enterprise. In the connectionist framework, mental operations are studied by simulating learning and processing within networks of artificial neurons. With that in mind, we discuss recent progress in connectionist models of auditory word recognition, reading, morphology, and syntactic processing. We argue that connectionist models can capture many important characteristics of how language is learned, represented, and processed, as well as providing new insights about the source of these behavioral patterns. Just as importantly, the networks naturally capture irregular (non-rule-like) patterns that are common within languages, something that has been difficult to reconcile with rule-based accounts of language without positing separate mechanisms for rules and exceptions

Creation of a multiple-use recombinant inbred line population for the development of molecular markers in soft white winter wheat

Tese de doutoramento em Física (Pré-Bolonha), especialidade de Física Experimental, apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraPositron emission tomography based on resistive plate chambers (RPC-PET) has been proposed for both preclinical and clinical applications. We firstly present imaging results of needle-like and planar 22Na sources obtained with a prototype of a high-acceptance small-animal RPC-PET. The two detector modules utilized in this experiment had an effective front face of 6.4 x 6.4 cm^2 and consisted of 5 gas gaps and 6 glass electrodes with a total thickness of 5 mm. The data included lines of response (LORs) inclined up to 58º, and the depth of interaction (DOI) was accurately measured, demonstrating the parallax-free property inherent to RPC-PET. The maximum likelihood expectation-maximization (MLEM) reconstruction of the acquired data yielded an excellent and stable resolution of 0.4 mm full width at half maximum (FWHM). Concurrently, we pursued studies of a suggested whole-body single-bed RPC-PET. It has been shown by simulation that RPC-PET with an axial field-of-view (AFOV) of 2.4 m is feasible and yields an absolute sensitivity at least one order of magnitude superior to that of typical crystal-based PET scanners. In addition, RPC-PET offers an important time-of-flight (TOF) advantage and provides a potentially very-high spatial resolution at the detector level. In the second part of this work, a fully three-dimensional reconstruction algorithm capable of processing the very inclined LORs from large AFOV systems such as RPC-PET is demonstrated. It relies on the application of a TOF-based-kernel into the MLEM algorithm. With the 300 ps FWHM time resolution, already experimentally demonstrated, a rejection of 63% of the body-scattered events is obtained. We present reconstructed results from blind simulations corresponding to the anthropomorphic phantom, NCAT, with oncological lesions introduced into different locations within the human body. A comparison between 300 and 600 ps FWHM TOF reconstructed images is performed, with an increasing detectability being observed for a better TOF resolution. We finally compare issues related to image convergence speed. An alternative new approach, which consists in dividing the full-body data into nine different image regions that are reconstructed independently with graphical processing unit (GPU) assistance, provides a six times faster reconstruction compared with a GPU-based whole-body reconstruction. For a 300 ps FWHM RPC-PET scanner, this allows reaching a reconstructed image, that results from 1.6 x 10^10 annihilations within 7 minutes and upon injection of 2 mCi, just 4 minutes after the end of data acquisition. We conclude that RPC-PET is well oriented to compete with other commercial PET scanners in the global market.A tomografia por emissão de positrões baseada em detectores do tipo câmaras de placas resistivas (RPC-PET) foi proposta para aplicação em ensaios com pequenos animais e na prática clínica. Neste trabalho, apresentamos primeiramente resultados experimentais obtidos a partir de um protótipo RPC-PET de alta aceitação para pequenos animais. Foram obtidas imagens de fontes do radioisótopo 22Na, uma quase pontual e outra planar. Usámos dois módulos de detectores RPC com uma área activa de 6.4 x 6.4 cm^2 e uma espessura de 5 mm, constituída por 6 vidros empilhados e 5 espaços gasosos definidos entre eles. Os dados adquiridos incluíram linhas de coincidência (LORs) inclinadas até um ângulo de 58º, tornando essencial a medida precisa da profundidade de interacção. A identificação dos espaços gasosos onde ocorreram as avalanches permitiu demonstrar a ausência de erro de paralaxe nas medidas realizadas com o RPC-PET para pequenos animais. A partir da reconstrução dos dados processados com o algoritmo maximum likelihood expectation-maximization (MLEM), obtivemos uma resolução espacial com largura a meia altura (FWHM) de 0.4 mm, excelente e estável. Em paralelo, continuámos a estudar as potencialidades de um protótipo RPC-PET de corpo inteiro e cama única, orientado para pessoas. Já foi anteriormente demonstrado por simulação que um scanner RPC-PET com 2.4 m de campo de visão axial (AFOV) é viável e permitirá o aumento de sensibilidade de pelo menos uma ordem de grandeza em relação aos scanners PET com cristais. Duas outras virtudes do RPC-PET são a sua capacidade de medição do tempo de voo (TOF) dos fotões e a elevada resolução espacial ao nível do detector. Na segunda parte deste trabalho apresentamos um algoritmo de reconstrução, totalmente tridimensional, capaz de processar LORs muito inclinadas em sistemas com um AFOV longo, como é o caso do RPC-PET. Este algoritmo acrescenta um kernel ao algoritmo MLEM, baseado na informação de TOF. Com uma resolução temporal de 300 ps FWHM, já experimentalmente comprovada, é possível rejeitar 63% dos eventos dispersados no corpo humano. Exibimos imagens reconstruídas obtidas a partir de simulações do fantoma antropomórfico, NCAT, com lesões oncológicas situadas em diferentes locais do corpo humano. A comparação entre imagens conseguidas com resoluções temporais de 300 ps e 600 ps FWHM, permite observar uma detectabilidade acrescida associada à melhor resolução de TOF. Por último, são estudados os tempos de convergência da reconstrução. Um método inovador e alternativo, que consiste na divisão dos dados do corpo humano em nove regiões e na reconstrução independente desses dados com recurso a unidades de processamento gráfico (GPUs), permite uma reconstrução seis vezes mais rápida do que a reconstrução de corpo inteiro também com o auxílio de GPUs. A partir de dados de 1.6 x 10^10 aniquilações ocorridas durante uma aquisição de 7 minutos e para uma actividade injectada de 2 mCi, um scanner RPC-PET com uma resolução temporal de 300 ps FWHM permitirá obter uma imagem reconstruída apenas 4 minutos após o fim da aquisição. Podemos assim concluir que o RPC-PET está bem colocado para competir no mercado dos scanners PET comerciais

Psychometric properties of the Quality of Life Inventory-Disability (QI-Disability) measure

PURPOSE: Children with intellectual disability encounter daily challenges beyond those captured in current quality of life measures. This study evaluated a new parent-report measure for children with intellectual disability, the Quality of Life Inventory-Disability (QI-Disability). METHODS: QI-Disability was administered to 253 primary caregivers of children (aged 5-18 years) with intellectual disability across four diagnostic groups: Rett syndrome, Down syndrome, cerebral palsy or autism spectrum disorder. Exploratory and confirmatory factor analyses were conducted and goodness of fit of the factor structure assessed. Associations between QI-Disability scores, and diagnostic and age groups were examined with linear regression. RESULTS: Six domains were identified: physical health, positive emotions, negative emotions, social interaction, leisure and the outdoors, and independence. Goodness-of-fit statistics were satisfactory and similar for the whole sample and when the sample was split by ability to walk or talk. On 100 point scales and compared to Rett syndrome, children with Down syndrome had higher leisure and the outdoors (coefficient 10.6, 95% CI 3.4,17.8) and independence (coefficient 29.7, 95% CI 22.9, 36.5) scores, whereas children with autism spectrum disorder had lower social interaction scores (coefficient -?12.8, 95% CI -?19.3, -?6.4). Scores for positive emotions (coefficient -?6.1, 95% CI -?10.7, -?1.6) and leisure and the outdoors (coefficient 5.4, 95% CI -?10.6, -?0.1) were lower for adolescents compared with children. CONCLUSIONS: Initial evaluation suggests that QI-Disability is a reliable and valid measure of quality of life across the spectrum of intellectual disability. It has the potential to allow clearer identification of support needs and measure responsiveness to interventions

Paediatric obsessive-compulsive disorder and depressive symptoms: clinical correlates and CBT treatment outcomes.

Depression frequently co-occurs with paediatric obsessive-compulsive disorder (OCD), yet the clinical correlates and impact of depression on CBT outcomes remain unclear. The prevalence and clinical correlates of depression were examined in a paediatric specialist OCD-clinic sample (N = 295; Mean = 15 [7 - 18] years, 42 % female), using both dimensional (Beck Depression Inventory-youth; n = 261) and diagnostic (Development and Wellbeing Assessment; n = 127) measures of depression. The impact of depressive symptoms and suspected disorders on post-treatment OCD severity was examined in a sub-sample who received CBT, with or without SSRI medication (N = 100). Fifty-one per-cent of patients reported moderately or extremely elevated depressive symptoms and 26 % (95 % CI: 18 - 34) met criteria for a suspected depressive disorder. Depressive symptoms and depressive disorders were associated with worse OCD symptom severity and global functioning prior to CBT. Individuals with depression were more likely to be female, have had a psychiatric inpatient admission and less likely to be attending school (ps < 0.01). OCD and depressive symptom severity significantly decreased after CBT. Depressive symptoms and depressive disorders predicted worse post-treatment OCD severity (βs = 0.19 and 0.26, ps < 0.05) but became non-significant when controlling for pre-treatment OCD severity (βs = 0.05 and 0.13, ns). Depression is common in paediatric OCD and is associated with more severe OCD and poorer functioning. However, depression severity decreases over the course of CBT for OCD and is not independently associated with worse outcomes, supporting the recommendation for treatment as usual in the presence of depressive symptoms