584 research outputs found

    Learning and Using Context on a Humanoid Robot Using Latent Dirichlet Allocation

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    2014 Joint IEEE International Conferences on Development and Learning and Epigenetic Robotics (ICDL-Epirob), Genoa, Italy, 13-16 October 2014In this work, we model context in terms of a set of concepts grounded in a robot's sensorimotor interactions with the environment. For this end, we treat context as a latent variable in Latent Dirichlet Allocation, which is widely used in computational linguistics for modeling topics in texts. The flexibility of our approach allows many-to-many relationships between objects and contexts, as well as between scenes and contexts. We use a concept web representation of the perceptions of the robot as a basis for context analysis. The detected contexts of the scene can be used for several cognitive problems. Our results demonstrate that the robot can use learned contexts to improve object recognition and planning.Scientific and Technological Research Council of Turkey (TUBiTAK

    Learning Context on a Humanoid Robot using Incremental Latent Dirichlet Allocation

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    In this article, we formalize and model context in terms of a set of concepts grounded in the sensorimotor interactions of a robot. The concepts are modeled as a web using Markov Random Field, inspired from the concept web hypothesis for representing concepts in humans. On this concept web, we treat context as a latent variable of Latent Dirichlet Allocation (LDA), which is a widely-used method in computational linguistics for modeling topics in texts. We extend the standard LDA method in order to make it incremental so that (i) it does not re-learn everything from scratch given new interactions (i.e., it is online) and (ii) it can discover and add a new context into its model when necessary. We demonstrate on the iCub platform that, partly owing to modeling context on top of the concept web, our approach is adaptive, online and robust: It is adaptive and online since it can learn and discover a new context from new interactions. It is robust since it is not affected by irrelevant stimuli and it can discover contexts after a few interactions only. Moreover, we show how to use the context learned in such a model for two important tasks: object recognition and planning.Scientific and Technological Research Council of TurkeyMarie Curie International Outgoing Fellowship titled “Towards Better Robot Manipulation: Improvement through Interaction

    Mainstreaming biodiversity for food and nutrition into policies and practice: methodologies and lessons learned from four countries

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    This paper outlines the methodology for mainstreaming biodiversity developed by the Biodiversity for Food and Nutrition Project (BFN), a multi-country initiative led by Brazil, Kenya, Sri Lanka and Turkey. BFN explored the nutritional properties of traditional and/or neglected native edible species, both wild and cultivated (including varieties and landraces), and used this knowledge to incorporate local agricultural biodiversity into national and global policy instruments that address food and nutrition security through the promotion of healthy, diversified and sustainable diets. Across the four countries, the project adopted a three-pillar approach for mainstreaming biodiversity for food and nutrition into policies and practices by: 1) Providing Evidence, 2) Influencing Policy, and 3) Raising Awareness. Case study examples from Brazil, Kenya, Turkey, and Sri Lanka demonstrate how the approach can be adapted to suit specific country contexts and how a multi-level, cross-sectoral partnership-based approach can create an enabling environment for mainstreaming biodiversity to improve nutrition

    Performance of a plastic scintillator developed using styrene monomer polymerization

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    This paper presents a newly developed plastic scintillator produced in collaboration with Turkiye Energy, Nuclear and Mineral Research Agency (TENMAK). The scintillator is manufactured using thermal polymerization of commercially available styrene monomer. The absorption spectrum of the scintillator exhibited two absorption bands at 225 nm and 340 nm, with an absorption edge observed at 410 nm. The wavelength of the emitted light was measured in the range of 400-800 nm, with a maximum intensity at 427 nm. Monoenergetic electrons from the 137Cs source were used to evaluate the characteristics of the new scintillator, particularly its light yield. As the light readout the MAPD-3NM type silicon photomultiplier array (4 x 4) with an active area of 15 x 15 mm2, assembled using single MAPDs with an active area of 3.7 x 3.7 mm2, was used. The light yield of the scintillator was determined to be 6134 photons/MeV. In addition, the efficiency of the scintillator for gamma rays with an energy of 662 keV was found to be approximately 1.8 %. A CmBe neutron source was employed to evaluate its fast neutron detection performance. However, neutron/gamma discrimination using pulse shape discrimination (charge integration) method was not observed. The results demonstrate the potential of a newly produced plastic scintillator for various applications, particularly in radiation monitoring and detection systems.Comment: 7 pages, 7 figure

    L1CAM mutation in association with X-linked hydrocephalus and Hirschsprung’s disease

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    X-linked hydrocephalus (XLH) is characterized by increased intracranial ventricle size and head circumference secondary to aqueduct of Sylvius congenital stenosis. Exceedingly rare is the concurrence of XLH and Hirschsprung’s disease (HSCR) with a theoretical incidence of 1 in 125–250 million cases. Herein, we are describing a case of a patient with concurrent XLH and HSCR. The patient was delivered via cesarean section at 37 weeks gestation and underwent uneventful ventriculoperitoneal shunt placement. As a part of a workup for constipation, we performed a rectal biopsy, which was consistent with HSCR. Genetics testing showed hemizygous for R558X hemizygous mutation in the L1CAM gene. A C → T nucleotide substitution in exon 13 resulted in replacement of an arginine codon with a stop codon, a nonsense mutation. Although it is widely accepted that HSCR represents the failure of early embryonic neural crest cells to migrate properly, the exact mechanism is not known. The association of HSCR with XLH in the presence of L1CAM mutations remains quite interesting because cell adhesion molecules are involved in the proper migration of neural components throughout the body. Additional studies are necessary to fully elucidate the relationship between XLH and HSCR in the presence of L1CAM mutations
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