1,602 research outputs found

    Image segmentation for human motion analysis: methods and applications

    Get PDF
    Human motion analysis is closely connected with the development of computational techniques capable of automatically identify objects represented in image sequences, track and analyse its movement. Feature extraction is generally the first step in the study of human motion in image sequences which is strictly related to human motion modelling [1]. Next step is feature correspondence, where the problem of matching features between two consecutives image frames is addressed. Finally high level processing can be used in several applications of Computer Vision like, for instance, in the recognition of human movements, activities or poses. This work will focus in the study of image segmentation methods and applications for human motion analysis. Image segmentation methods related to human motion need to deal with several challenges such as: dynamic backgrounds, for instance when the camera is in motion; lighting conditions that can change along the image sequences; occlusion problems, when the subject does not remain inside the workspace; or image sequences with more than one subject in the workspace at the same time. It is not easy to develop methods which can deal with all thes

    Methods to automatically build Point Distribution Models for objects like hand palms and faces represented in images

    Get PDF
    In this work we developed methods to automatically extract significant points of objects like hand palms and faces represented in images that can be used to build Point Distribution Models automatically. These models are further used to segment the modelled objects in new images, through the use of Active Shape Models or Active Appearance Models. These models showed to be efficient in the segmentation of objects, but had as drawback the fact that the labelling of the landmark points was usually manually made and consequently time consuming. Thus, in this paper we describe some methods capable to extract significant points of objects like hand palms and compare the segmentation results in new images

    Modelling and segmentation of the vocal track during speech production by using deformable models in magnetic resonance images

    Get PDF
    The first and second authors would like to thank the support of the PhD grants with references SFRH/BD/28817/2006 and SFRH/PROTEC/49517/2009, respectively, from Fundação para a Ciência e Tecnol ogia (FCT). This work was partially done in the scope of the project “Methodologies to Analyze Organs from Complex Medical Images – Applications to Fema le Pelvic Cavity”, wi th reference PTDC/EEA- CRO/103320/2008, financially supported by FCT.Since ancient times, speech production has attracted particularly interest aiming at reaching a deeper understanding of the mechanisms involved by considering both morphological and speech acoustic aspects. The central anatomical aspects and the physiology of the human vocal tract are common to all individuals. However, speech production is an exceptionally complex and individualistic process. Therefore, the modelling of the mechanisms involved in speech production implies the enclosing of adequate flexibility in order to consider individual variations accurately. In this work, the shape of vocal tract in the articulation of some European Portuguese (EP) sounds is evaluated by using deformable models applied in Magnetic Resonance (MR) images. Additionally, the deformable models built are afterwards used to automatically segment the modelled vocal tract in MR images. From the imaging modalities that have been take n into consideration in order to study the vocal tract shape and articulators, Magnetic Resonance Imaging (MRI) has been the most commonly accepted. Actually, the use of MRI allows the study of the entire human vocal tract and, in addition, the quality and resolution of soft-tissues and the use of non-ionizing radiation are key advantages presented by MRI. The deformable model used, commonly known as Point Distribution Model (PDM), was built from a set of training images acquired du ring artificially sustained articulations of 21 EP sounds. In a brief review, one can assert that PDM’s are obtained by a statistical analysis done on the co-ordinates of landmark points that represent the shape to be modelled: after aligning the training shapes, a Principal Component Analysis is performed in order to obtain the model mean shape and the modes of variation relatively to this mean shap e. Combining the geometrical information of the PDM with the grey levels of the landmark points us ed in its building one can build the Active Shape Models (ASM) and the Active Appearance Models (AAM). With these enhanced models is possible to segment the modelled shape in new images in a fully automated way. From the experimental results obtained in this work, one may conclude that the PDM built could efficiently characterize the behaviour of the voca l tract shape during the production of the EP sounds studied with MRI. Furthermore, one can ve rify that the ASM and the AAM built could be used to segment the modelled vocal tract in MR images in a successful manner. Therefore, the deformable models built should be considered towards the efficient and automatic study of the vocal tract during speech production with MRI, in particular for enhanced speech production simulation and speech rehabilitation therapies.Fundação para a Ciência e Tecnologia (FCT

    Disciplinas de custos: uma análise nos cursos de Ciências Contábeis das IES do sistema ACAFE

    Get PDF
    A informação de custos, diante de um mercado de competitividade crescente, apresenta-se como uma base importante ao processo decisório, além de implicar novos paradigmas na gestão dos negócios. Desta forma, torna-se relevante o oferecimento de disciplinas de custos no Curso de Ciências Contábeis onde a contabilidade de custos e seu processo de ensino devem direcionar o aluno, a partir do estudo acadêmico, ao processo externo, ou seja, ao mercado tomador do profissional provido de conhecimento contábil.Considerando a relevância das disciplinas de custos no Curso de Ciências Contábeis das Instituições de Ensino Superior (IES), este artigo tem como objetivo verificar as congruências e divergências destas disciplinas ofertadas nos Cursos de Ciências Contábeis das universidades ligadas à Associação Catarinense das Fundações Educacionais (ACAFE). A metodologia da pesquisa consubstancia-se de um estudo exploratório, realizado por meio de levantamento, com abordagem predominantemente qualitativa. Utilizou-se para análise o conteúdo de ementa, a carga horária e a disposição das disciplinas de custos na grade curricular nestas instituições. A técnica estatística empregada foi análise de clusters. Diante deste estudo que teve como objetivo a verificação das congruências e divergências das disciplinas de custos ofertadas nos Cursos de Ciências Contábeis das instituições ligadas à ACAFE, conclui-se que estas instituições estabelecem um agrupamento predominante, mesmo que na análise isolada de algumas variáveis isto não ocorra. Os resultados da pesquisa evidenciam que na variável ementa, o cluster mais representativo apontou 9 instituições, representando o maior grupo com 56,25% do total de instituições pesquisadas. Na variável fase, 10 instituições apresentaram congruência, pois oferecem as disciplinas de custos em períodos semelhantes. Na variável carga horária, 10 instituições apresentam similaridade no oferecimento das disciplinas de custos e análise de custos com 120 h/a. Conclui-se que, num contexto geral, há um acentuado nível de congruência nas disciplinas de custos entre as universidades analisadas, apesar de divergências encontradas na análise isolada de algumas variáveis

    BioWorkbench: A High-Performance Framework for Managing and Analyzing Bioinformatics Experiments

    Get PDF
    Advances in sequencing techniques have led to exponential growth in biological data, demanding the development of large-scale bioinformatics experiments. Because these experiments are computation- and data-intensive, they require high-performance computing (HPC) techniques and can benefit from specialized technologies such as Scientific Workflow Management Systems (SWfMS) and databases. In this work, we present BioWorkbench, a framework for managing and analyzing bioinformatics experiments. This framework automatically collects provenance data, including both performance data from workflow execution and data from the scientific domain of the workflow application. Provenance data can be analyzed through a web application that abstracts a set of queries to the provenance database, simplifying access to provenance information. We evaluate BioWorkbench using three case studies: SwiftPhylo, a phylogenetic tree assembly workflow; SwiftGECKO, a comparative genomics workflow; and RASflow, a RASopathy analysis workflow. We analyze each workflow from both computational and scientific domain perspectives, by using queries to a provenance and annotation database. Some of these queries are available as a pre-built feature of the BioWorkbench web application. Through the provenance data, we show that the framework is scalable and achieves high-performance, reducing up to 98% of the case studies execution time. We also show how the application of machine learning techniques can enrich the analysis process

    Preserving the nutritional quality of crop plants under a changing climate: importance and strategies

    Get PDF
    Background: Global climate is changing more rapidly than ever, threatening plant growth and productivity while exerting considerable direct and indirect effects on the quality and quantity of plant nutrients. Scope: This review focuses on the global impact of climate change on the nutritional value of plant foods. It showcases the existing evidence linking the effects of climate change factors on crop nutrition and the concentration of nutrients in edible plant parts. It focuses on the effect of elevated CO2 (eCO2), elevated temperature (eT), salinity, waterlogging and drought stresses, and what is known regarding their direct and indirect influence on nutrient availability. Furthermore, it provides possible strategies to preserve the nutritional composition of plant foods under changing climates. Conclusions: Climate change has an impact on the accumulation of minerals and protein in crop plants, with eCO2 being the underlying factor of most of the reported changes. The effects are clearly dependent on the type, intensity and duration of the imposed stress, plant genotype and developmental stage. Strong interactions (both positive and negative) can be found between individual climatic factors and soil availability of nitrogen (N), potassium (K), iron (Fe) and phosphorous (P). The development of future interventions to ensure that the world's population has access to plentiful, safe and nutritious food may need to rely on breeding for nutrients under the context of climate change, including legumes in cropping systems, better farm management practices and utilization of microbial inoculants that enhance nutrient availability.info:eu-repo/semantics/publishedVersio

    Shortcomings of phylogenetic studies on recent radiated insular groups: a meta-analysis using Cabo Verde biodiversity

    Get PDF
    ReviewOver the previous decades, numerous studies focused on how oceanic islands have contributed to determine the phylogenetic relationships and times of origin and diversification of di erent endemic lineages. The Macaronesian Islands (i.e., Azores, Madeira, Selvagens, Canaries, and Cabo Verde), harbour biotas with exceptionally high levels of endemism. Within the region, the vascular plants and reptiles constitute two of the most important radiations. In this study we compare relevant published phylogenetic data and diversification rates retrieved within Cabo Verde endemic lineages and discuss the importance of choosing appropriate phylogeny-based methods to investigate diversification dynamics on islands. From this selective literature-based review, we summarize the software packages used in Macaronesian studies and discuss their adequacy considering the published data to obtain well-supported phylogenies in the target groups. We further debate the importance of Next Generation Sequencing (NGS), to investigate the evolutionary processes of diversification in the Macaronesian Islands. Analysis of genomic data provides phylogenetic resolution for rapidly evolving species radiations, suggesting a great potential to improve the phylogenetic signal and divergence time estimates in insular lineages. The most important Macaronesian reptile radiations provide good case-studies to compare classical phylogenetic methods with new tools, such as phylogenomics, revealing a high value for research on this hotspot areainfo:eu-repo/semantics/publishedVersio

    Relationship between seed traits and pasting and cooking behaviour in a pulse germplasm collection

    Get PDF
    Development of food products from legume flours is increasing. Seed and flour characteristics must be analysed for selection of the best screening quality traits. With this purpose, germplasm collections of faba bean (Vicia faba), chickpea (Cicer arietinum), lentil (Lens culinaris) and grass pea (Lathyrus sativus) were evaluated for their physicochemical, pasting and cooking characteristics. The accessions were grouped accordingly to several seed traits (size, shape, colour, variety and surface) that affected final viscosity, cooking time, hydration capacity and seed weight. In general, seed weight was correlated with hydration capacity. Among species, faba bean revealed higher values of pasting parameters. Cooking time was significantly negatively correlated with final viscosity (-0.298) and positively correlated with seed weight (0.601). The general variance was analysed by using principal component analysis, which allowed identification of specific accessions with important traits such as higher protein or fibre content, hydration capacity or seed weight.info:eu-repo/semantics/publishedVersio
    corecore