1,480 research outputs found

    Object segmentation in depth maps with one user click and a synthetically trained fully convolutional network

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    With more and more household objects built on planned obsolescence and consumed by a fast-growing population, hazardous waste recycling has become a critical challenge. Given the large variability of household waste, current recycling platforms mostly rely on human operators to analyze the scene, typically composed of many object instances piled up in bulk. Helping them by robotizing the unitary extraction is a key challenge to speed up this tedious process. Whereas supervised deep learning has proven very efficient for such object-level scene understanding, e.g., generic object detection and segmentation in everyday scenes, it however requires large sets of per-pixel labeled images, that are hardly available for numerous application contexts, including industrial robotics. We thus propose a step towards a practical interactive application for generating an object-oriented robotic grasp, requiring as inputs only one depth map of the scene and one user click on the next object to extract. More precisely, we address in this paper the middle issue of object seg-mentation in top views of piles of bulk objects given a pixel location, namely seed, provided interactively by a human operator. We propose a twofold framework for generating edge-driven instance segments. First, we repurpose a state-of-the-art fully convolutional object contour detector for seed-based instance segmentation by introducing the notion of edge-mask duality with a novel patch-free and contour-oriented loss function. Second, we train one model using only synthetic scenes, instead of manually labeled training data. Our experimental results show that considering edge-mask duality for training an encoder-decoder network, as we suggest, outperforms a state-of-the-art patch-based network in the present application context.Comment: This is a pre-print of an article published in Human Friendly Robotics, 10th International Workshop, Springer Proceedings in Advanced Robotics, vol 7. The final authenticated version is available online at: https://doi.org/10.1007/978-3-319-89327-3\_16, Springer Proceedings in Advanced Robotics, Siciliano Bruno, Khatib Oussama, In press, Human Friendly Robotics, 10th International Workshop,

    An Intelligent Multicriteria Model for Diagnosing Dementia in People Infected with Human Immunodeficiency Virus

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    Hybrid models to detect dementia based on Machine Learning can provide accurate diagnoses in individuals with neurological disorders and cognitive complications caused by Human Immunodeficiency Virus (HIV) infection. This study proposes a hybrid approach, using Machine Learning algorithms associated with the multicriteria method of Verbal Decision Analysis (VDA). Dementia, which affects many HIV-infected individuals, refers to neurodevelopmental and mental disorders. Some manuals standardize the information used in the correct detection of neurological disorders with cognitive complications. Among the most common manuals used are the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) of the American Psychiatric Association and the International Classification of Diseases, 10th edition (ICD-10)—both published byWorld Health Organization (WHO). The model is designed to explore the predictive of specific data. Furthermore, a well-defined database data set improves and optimizes the diagnostic models sought in the research.info:eu-repo/semantics/publishedVersio

    Detection of RHDV strains in the Iberian hare (Lepus granatensis): earliest evidence of rabbit lagovirus cross-species infection

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.Rabbit hemorrhagic disease virus (RHDV) is a highly lethal Lagovirus, family Caliciviridae, that threatens European rabbits (Oryctolagus cuniculus). Although a related virus severely affects hares, cross-species infection was only recently described for new variant RHDV in Cape hares (Lepus capensis mediterraneus). We sequenced two strains from dead Iberian hares (Lepus granatensis) collected in the 1990s in Portugal. Clinical signs were compatible with a Lagovirus infection. Phylogenetic analysis of the complete capsid gene positioned them in the RHDV genogroup that circulated on the Iberian Peninsula at that time. This is the earliest evidence of RHDV affecting a species other than European rabbits.This work was supported by FCT (Fundação para a Ciência e a Tecnologia; research project ref.: FCT-ANR/BIABIC/0043/2012). FCT also supported the doctoral grants of AML and AP (refs.: SFRH/BD/78738/2011 and SFRH/BD/71252/2010) and the FCT Investigator grant of JA (ref.: IF/01396/2013). “Genomics Applied To Genetic Resources” co-financed by North Portugal Regional Operational Programme 2007/2013 (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF), also supported this work.Peer Reviewe

    Functional characterization and evolution ofPTH/PTHrP receptors: insights from the chicken

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    The parathyroid hormone (PTH)-family consists of a group of structurally related factors that regulate calcium and bone homeostasis and are also involved in development of organs such as the heart, mammary gland and immune system. They interact with specific members of family 2 B1 G-protein coupled receptors (GPCRs), which have been characterised in teleosts and mammals. Two PTH/PTHrP receptors, PTH1R and PTH2R exist in mammals and in teleost fish a further receptor PTH3R has also been identified. Recently in chicken, PTH-family members involved in calcium transport were characterized and specific PTHRs are suggested to exist although they have not yet been isolated or functionally characterized. The aim of this study is to further explore the evolution and function of the vertebrate PTH/PTHrP system through the isolation, phylogenetic analysis and functional characterization of the chicken receptors. Results Two PTHRs were isolated in chicken and sequence comparison and phylogenetic analysis indicate that the chicken receptors correspond to PTH1R and PTH3R, which emerged prior to the teleost/tetrapod divergence since they are present in cartilaginous fish. The vertebrate PTH2R receptor and its ligand TIP39 have been lost from bird genomes. Chicken PTH1R and PTH3R have a divergent and widespread tissue expression and are also evident in very early embryonic stages of development. Receptor stimulation studies using HEK293 cells stably expressing the chicken PTH1R and PTH3R and monitoring cAMP production revealed they are activated by chicken 1–34 N-terminal PTH-family peptides in a dose dependent manner. PTH-L and PTHrP were the most effective peptides in activating PTH1R (EC50 = 7.7 nM and EC50 = 22.7 nM, respectively). In contrast, PTH-L (100 nM) produced a small cAMP accumulation on activation of PTH3R but PTHrP and PTH (EC50 = 2.5 nM and EC50 = 22.1 nM, respectively) readily activated the receptor. PTHrP also stimulated intracellular Ca2+ accumulation on activation of PTH1R but not PTH3R. Conclusion Two PTHR homologues of the vertebrate PTH1R and PTH3R were isolated and functionally characterized in chicken. Their distinct pattern of expression during embryo development and in adult tissues, together with their ligand preference, suggests that they have acquired specific functions, which have contributed to their maintenance in the genome. PTH2R and its activating ligand, TIP39, are absent from bird genomes. Nonetheless identification of putative PTH2R and TIP39 in the genome of an ancient agnathan, lamprey, suggests the PTH/PTHrP ligand and receptor family was already present in an early basal paraphyletic group of vertebrates and during the vertebrate radiation diverged via gene/genome duplication and deletion events. Knowledge of the role PTH/PTHrP system in early vertebrates will help to establish evolution of function.Peer Reviewe

    Chaos in the square billiard with a modified reflection law

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    The purpose of this paper is to study the dynamics of a square billiard with a non-standard reflection law such that the angle of reflection of the particle is a linear contraction of the angle of incidence. We present numerical and analytical arguments that the nonwandering set of this billiard decomposes into three invariant sets, a parabolic attractor, a chaotic attractor and a set consisting of several horseshoes. This scenario implies the positivity of the topological entropy of the billiard, a property that is in sharp contrast with the integrability of the square billiard with the standard reflection law.Comment: 17 figure

    Hybrid model for early identification post-Covid-19 sequelae

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    Artificial Intelligence techniques based on Machine Learning algorithms, Neural Networks and Naïve Bayes can optimise the diagnostic process of the SARS-CoV-2 or Covid-19. The most significant help of these techniques is analysing data recorded by health professionals when treating patients with this disease. Health professionals' more specific focus is due to the reduction in the number of observable signs and symptoms, ranging from an acute respiratory condition to severe pneumonia, showing an efficient form of attribute engineering. It is important to note that the clinical diagnosis can vary from asymptomatic to extremely harsh conditions. About 80% of patients with Covid-19 may be asymptomatic or have few symptoms. Approximately 20% of the detected cases require hospital care because they have difficulty breathing, of which about 5% may require ventilatory support in the Intensive Care Unit. Also, the present study proposes a hybrid approach model, structured in the composition of Artificial Intelligence techniques, using Machine Learning algorithms, associated with multicriteria methods of decision support based on the Verbal Decision Analysis methodology, aiming at the discovery of knowledge, as well as exploring the predictive power of specific data in this study, to optimise the diagnostic models of Covid-19. Thus, the model will provide greater accuracy to the diagnosis sought through clinical observation.info:eu-repo/semantics/publishedVersio

    Application of chitosan-based coatings on frozen salmon - Sensory assessment and retail simulation approach

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    GLUPOR 12 - 12nd International Meeting of the Portuguese Carbohydrate Chemistry GroupDue to an increase in fish consumption over the past years , in comb ination with the perishable nature of fish , the fish industry has given an added focus on the improvement of the currently used fish preservation techniques. Chitosan coatings may add improvements to the traditional water glazing , name ly in physical and ant i- microbial protection , allowing for shelf life extension. Nevertheless , during retail storage , frozen fish products can suffer temperature variations that lead to a decrease in quality. These temperature var iations can be caused by a multitude of reasons , some of which are easy to control , while others are due to unforeseen circumstances . In either case , thermal stress can often affect frozen fish products and this effect is of considerable importance . This work was meant to determ ine the influence of chitosan coatings in the organoleptic characteristics of salmon as well as report a strategy to help mitigate the effects of thermal stress of frozen fish samples .A 15 g/L chitosan solution was applied on frozen salmon samples through dipping at a temperature of 8 °C, wi th a dipping time of 10 s; water glazing was applied as blank treatment at 0.5 °C, with a dipping time of 40 s. Some of the samples were submitted to retail- simulated thermal stress conditions (i. e. a temperature variation of -15 °C to -5 °C was enforced ), and studied during a 70-days long experiment , while others were used to assess the sensory properties of chitosan coat ings on Atlantic salmon (Sa/mo salar) and were compared with uncoated and water glazed samples over a six-month storage period at -18 °C. Retail simulation samples were tested for variations in pH , coat i ng loss and color , while samples used for sensory analys is were evaluated by a sensory panel (frozen , frozen+thawed and frozen +thawed+cooked samples were assessed ,) regarding its organolept ic properties , and textural analysis , by means of a TPA (texture profile analys is ). Samples analys is common to both exper iments were microbiological stabi lity, assessed through TVC (ISO 4833-1 :2013 standard) , and chemical stability , determined as TVB-N (N P 2930 :2009 standard ). Through coating loss, it was possible to verify that chitosan coatings offer better protect ion, with water glazed samples becoming virtually unprotected after the evaluation period, with losses of more than 80 % of its glazing , while chitosan coated samples maintained 50 % of its coating. Extrapolat i ng this data to complete loss of water glazing shows an increase in shel f life of at le ast 26 % in chitosan coated samples. No significant changes between samples were obtained in the other parameters assessed . The anti-m icrobial effect of chitosan was confirmed through TVC which showed a reduction in microbial counts in chitosan coated samp les , whi le while TVB-N results showed to remain stable , for both experiments . The proven anti - microbial effect of chitosan coated samples in conjunction with a slower coating loss leads to an expected increase in shelf life , even in unforeseen circumstances of temperature change in retail transportation. Textural results from the TPA analysis showed no significant differences between different coatings. Results of the trained panel indicated that for frozen samples ch itosan was the preferred choice , while no significant differences existed between chitosan -coated and glazed samples in thawed and cooked samples. Flavor diffu sion from the chitosan coating to the samples was assessed by Principal Component Analysis and no correlation between coating type and sample flavor could be established , meaning that no chitosan flavor was detected by the panellists.Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/044691/2013 unit and COMPETE 2020 (POCl-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norteinfo:eu-repo/semantics/publishedVersio

    Have the cake and eat it: optimizing nondestructive DNA metabarcoding of macroinvertebrate samples for freshwater biomonitoring

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    Resource ArticleDNA metabarcoding can contribute to improving cost‐effectiveness and accuracy of biological assessments of aquatic ecosystems, but significant optimization and standardization efforts are still required to mainstream its application into biomonitoring programmes. In assessments based on freshwater macroinvertebrates, a key challenge is that DNA is often extracted from cleaned, sorted and homogenized bulk samples, which is time‐consuming and may be incompatible with sample preservation requirements of regulatory agencies. Here, we optimize and evaluate metabarcoding procedures based on DNA recovered from 96% ethanol used to preserve field samples and thus including potential PCR inhibitors and nontarget organisms. We sampled macroinvertebrates at five sites and subsampled the preservative ethanol at 1 to 14 days thereafter. DNA was extracted using column‐based enzymatic (TISSUE) or mechanic (SOIL) protocols, or with a new magnetic‐based enzymatic protocol (BEAD), and a 313‐bp COI fragment was amplified. Metabarcoding detected at least 200 macroinvertebrate taxa, including most taxa detected through morphology and for which there was a reference barcode. Better results were obtained with BEAD than SOIL or TISSUE, and with subsamples taken 7–14 than 1–7 days after sampling, in terms of DNA concentration and integrity, taxa diversity and matching between metabarcoding and morphology. Most variation in community composition was explained by differences among sites, with small but significant contributions of subsampling day and extraction method, and negligible contributions of extraction and PCR replication. Our methods enhance reliability of preservative ethanol as a potential source of DNA for macroinvertebrate metabarcoding, with a strong potential application in freshwater biomonitoringinfo:eu-repo/semantics/publishedVersio
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