62 research outputs found

    Marker based Thermal-Inertial Localization for Aerial Robots in Obscurant Filled Environments

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    For robotic inspection tasks in known environments fiducial markers provide a reliable and low-cost solution for robot localization. However, detection of such markers relies on the quality of RGB camera data, which degrades significantly in the presence of visual obscurants such as fog and smoke. The ability to navigate known environments in the presence of obscurants can be critical for inspection tasks especially, in the aftermath of a disaster. Addressing such a scenario, this work proposes a method for the design of fiducial markers to be used with thermal cameras for the pose estimation of aerial robots. Our low cost markers are designed to work in the long wave infrared spectrum, which is not affected by the presence of obscurants, and can be affixed to any object that has measurable temperature difference with respect to its surroundings. Furthermore, the estimated pose from the fiducial markers is fused with inertial measurements in an extended Kalman filter to remove high frequency noise and error present in the fiducial pose estimates. The proposed markers and the pose estimation method are experimentally evaluated in an obscurant filled environment using an aerial robot carrying a thermal camera.Comment: 10 pages, 5 figures, Published in International Symposium on Visual Computing 201

    Detection of Aruco Markers Using the Quadrilateral Sum Conjuncture

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    Fiducial Markers are heavily used for pose estimation in many applications from robotics to augmented reality. In this paper we present an algorithm for the detection of aruco marker at larger distance. The algorithm uses the quadrilateral sum conjecture and analyzes the sum of the cosine of the internal angles to detect squares at larger distances. Experiments conducted showed that the developed solution was able to improve the detection distance when compared to other methods that use similar marker while keeping similar pose estimation precision.publishe

    Evaluating the suitability of several AR devices and tools for industrial applications

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    In recent years, there has been an increasing interest in Industrial Augmented Reality (IAR) due to its prominent role in the ongoing revolution known as Industry 4.0. For companies and industries it is essential to evaluate carefully which of the developed AR-based technologies to adopt, and when, for tasks such as training, maintenance, assistance, and collaborative design. There is also a wide array of hardware and software alternatives on the market, characterized by a significant heterogeneity in terms of functionalities, performance and cost. With this work, our objective is to study and compare some widely available devices and Software Development Kits (SDKs) for AR by leveraging a set of evaluation criteria derived from the actual literature which have been deemed capable to qualify the above assets as suitable for industrial applications. Such criteria include the operative range, robustness, accuracy and stability. Both marker-based and marker-less solutions have been considered, in order to investigate a wide range of possible use cases

    Augmented Reality Application in Manufacturing Industry: Maintenance and Non-destructive Testing (NDT) Use Cases

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    In recent years, a structural transformation of the manufacturing industry has been occurring as a result of the digital revolution. Thus, digital tools are now systematically used throughout the entire value chain, from design to production to marketing, especially virtual and augmented reality. Therefore, the purpose of this paper is to review, through concrete use cases, the progress of these novel technologies and their use in the manufacturing industry

    Metarhizium anisopliae Pathogenesis of Mosquito Larvae: A Verdict of Accidental Death

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    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host

    Feasibility of a walking virtual reality system for rehabilitation: objective and subjective parameters

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    [EN] Background: Even though virtual reality (VR) is increasingly used in rehabilitation, the implementation of walking navigation in VR still poses a technological challenge for current motion tracking systems. Different metaphors simulate locomotion without involving real gait kinematics, which can affect presence, orientation, spatial memory and cognition, and even performance. All these factors can dissuade their use in rehabilitation. We hypothesize that a marker-based head tracking solution would allow walking in VR with high sense of presence and without causing sickness. The objectives of this study were to determine the accuracy, the jitter, and the lag of the tracking system and its elicited sickness and presence in comparison of a CAVE system. Methods: The accuracy and the jitter around the working area at three different heights and the lag of the head tracking system were analyzed. In addition, 47 healthy subjects completed a search task that involved navigation in the walking VR system and in the CAVE system. Navigation was enabled by natural locomotion in the walking VR system and through a specific device in the CAVE system. An HMD was used as display in the walking VR system. After interacting with each system, subjects rated their sickness in a seven-point scale and their presence in the Slater-Usoh-Steed Questionnaire and a modified version of the Presence Questionnaire. Results: Better performance was registered at higher heights, where accuracy was less than 0.6 cm and the jitter was about 6 mm. The lag of the system was 120 ms. Participants reported that both systems caused similar low levels of sickness (about 2.4 over 7). However, ratings showed that the walking VR system elicited higher sense of presence than the CAVE system in both the Slater-Usoh-Steed Questionnaire (17.6 +/- 0.3 vs 14.6 +/- 0.6 over 21, respectively) and the modified Presence Questionnaire (107.4 +/- 2.0 vs 93.5 +/- 3.2 over 147, respectively). Conclusions: The marker-based solution provided accurate, robust, and fast head tracking to allow navigation in the VR system by walking without causing relevant sickness and promoting higher sense of presence than CAVE systems, thus enabling natural walking in full-scale environments, which can enhance the ecological validity of VR-based rehabilitation applications.The authors wish to thank the staff of LabHuman for their support in this project, especially José Miguel Martínez and José Roda for their assistance. This study was funded in part by Ministerio de Economia y Competitividad of Spain (Project NeuroVR, TIN2013-44741-R and Project REACT, TIN2014-61975-EXP), by Ministerio de Educacion y Ciencia of Spain (Project Consolider-C, SEJ2006-14301/PSIC), and by Universitat Politecnica de Valencia (Grant PAID-10-14).Borrego, A.; Latorre Grau, J.; Llorens Rodríguez, R.; Alcañiz Raya, ML.; Noé, E. (2016). Feasibility of a walking virtual reality system for rehabilitation: objective and subjective parameters. Journal of NeuroEngineering and Rehabilitation. 13:1-9. https://doi.org/10.1186/s12984-016-0174-1S1913Lee KM. Presence. Explicated Communication Theory. 2004;14(1):27–50.Riva G. Is presence a technology issue? Some insights from cognitive sciences. Virtual Reality. 2009;13(3):159–69.Banos RM, et al. Immersion and emotion: their impact on the sense of presence. Cyberpsychol Behav. 2004;7(6):734–41.Llorens R, et al. Tracking systems for virtual rehabilitation: objective performance vs. subjective experience. A practical scenario. Sensors (Basel). 2015;15(3):6586–606.Navarro MD, et al. Validation of a low-cost virtual reality system for training street-crossing. A comparative study in healthy, neglected and non-neglected stroke individuals. Neuropsychol Rehabil. 2013;23(4):597–618.Parsons TD. Virtual reality for enhanced ecological validity and experimental control in the clinical, affective and social neurosciences. Front Hum Neurosci. 2015;9:660.Cameirao MS, et al. Neurorehabilitation using the virtual reality based Rehabilitation Gaming System: methodology, design, psychometrics, usability and validation. J Neuroeng Rehabil. 2010;7:48.Llorens R, et al. Improvement in balance using a virtual reality-based stepping exercise: a randomized controlled trial involving individuals with chronic stroke. Clin Rehabil. 2015;29(3):261–8.Llorens R, et al. Videogame-based group therapy to improve self-awareness and social skills after traumatic brain injury. J Neuroeng Rehabil. 2015;12:37.Fong KN, et al. Usability of a virtual reality environment simulating an automated teller machine for assessing and training persons with acquired brain injury. J Neuroeng Rehabil. 2010;7:19.Levin MF, Weiss PL, Keshner EA. Emergence of virtual reality as a tool for upper limb rehabilitation: incorporation of motor control and motor learning principles. Phys Ther. 2015;95(3):415–25.Llorens R, et al. Effectiveness, usability, and cost-benefit of a virtual reality-based telerehabilitation program for balance recovery after stroke: a randomized controlled trial. Arch Phys Med Rehabil. 2015;96(3):418–25. e2.Cruz-Neira C, et al. Scientists in wonderland: A report on visualization applications in the CAVE virtual reality environment. In: 1993. Proceedings IEEE 1993 Symposium on Research Frontiers in Virtual Reality. 1993.Juan MC, Perez D. Comparison of the levels of presence and anxiety in an acrophobic environment viewed via HMD or CAVE. Presence. 2009;18(3):232–48.Yang YR, et al. Virtual reality-based training improves community ambulation in individuals with stroke: a randomized controlled trial. Gait Posture. 2008;28(2):201–6.Cho KH, Lee WH. Virtual walking training program using a real-world video recording for patients with chronic stroke: a pilot study. Am J Phys Med Rehabil. 2013;92(5):371–84.Darter BJ, Wilken JM. Gait training with virtual reality-based real-time feedback: improving gait performance following transfemoral amputation. Phys Ther. 2011;91(9):1385–94.Yang S, et al. Improving balance skills in patients who had stroke through virtual reality treadmill training. Am J Phys Med Rehabil. 2011;90(12):969–78.Walker ML, et al. Virtual reality-enhanced partial body weight-supported treadmill training poststroke: feasibility and effectiveness in 6 subjects. Arch Phys Med Rehabil. 2010;91(1):115–22.Riley PO, et al. A kinematic and kinetic comparison of overground and treadmill walking in healthy subjects. Gait Posture. 2007;26(1):17–24.Alton F, et al. A kinematic comparison of overground and treadmill walking. Clin Biomech. 1998;13(6):434–40.Lee SJ, Hidler J. Biomechanics of overground vs. treadmill walking in healthy individuals. J Appl Physiol. 2008;104(3).Slater M. Measuring presence: a response to the witmer and Singer presence questionnaire. Presence. 1999;8(5):560–5.Viau A, et al. Reaching in reality and virtual reality: a comparison of movement kinematics in healthy subjects and in adults with hemiparesis. J Neuroeng Rehabil. 2004;1(1):11.Parsons TD, et al. The potential of function-led virtual environments for ecologically valid measures of executive function in experimental and clinical neuropsychology. Neuropsychol Rehabil. 2015;11:1–31. doi: 10.1080/09602011.2015.1109524 .Aravind G, Lamontagne A. Perceptual and locomotor factors affect obstacle avoidance in persons with visuospatial neglect. J Neuroeng Rehabil. 2014;11:38.Darekar A, Lamontagne A, Fung J. Dynamic clearance measure to evaluate locomotor and perceptuo-motor strategies used for obstacle circumvention in a virtual environment. Hum Mov Sci. 2015;40:359–71.Whittle MW. Chapter 4 - Methods of gait analysis. In: Whittle MW, editor. Gait analysis. Edinburgh: Butterworth-Heinemann; 2007. p. 137–75.Hodgson E, et al. WeaVR: a self-contained and wearable immersive virtual environment simulation system. Behav Res Methods. 2015;47(1):296–307.Akizuki H, et al. Effects of immersion in virtual reality on postural control. Neurosci Lett. 2005;379(1):23–6.Thies SB, et al. Comparison of linear accelerations from three measurement systems during "reach & grasp". Med Eng Phys. 2007;29(9):967–72.Fiala M. Designing highly reliable fiducial markers. IEEE Trans Pattern Anal Mach Intell. 2010;32(7):1317–24.Garrido-Jurado S, et al. Automatic generation and detection of highly reliable fiducial markers under occlusion. Pattern Recognition. 2014;47(6):2280–92.Kim K, et al. Effects of virtual environment platforms on emotional responses. Comput Methods Programs Biomed. 2014;113(3):882–93.Slater M, Steed A. A virtual presence counter. Presence. 2000;9(5):413–34.Witmer BG, Singer MJ. Measuring presence in virtual environments: a presence questionnaire. Presence Teleop Virt. 1998;7(3):225–40.Martín-Gutiérrez J, et al. Design and validation of an augmented book for spatial abilities development in engineering students. Comput Graph. 2010;34(1):77–91.Lopez-Mir F, et al. Design and validation of an augmented reality system for laparoscopic surgery in a real environment. Biomed Res Int. 2013;2013:758491.Abawi DF, Bienwald J, Dorner R. Accuracy in optical tracking with fiducial markers: an accuracy function for ARToolKit. In: Third IEEE and ACM International symposium on mixed and augmented reality, ISMAR 2004. 2004.Malbezin P, Piekarski W, Thomas BH. Measuring ARTootKit accuracy in long distance tracking experiments. In: The first IEEE International workshop augmented reality toolkit. 2002.Paquette C, Paquet N, Fung J. Aging affects coordination of rapid head motions with trunk and pelvis movements during standing and walking. Gait Posture. 2006;24(1):62–9.Graham JE, et al. Walking speed threshold for classifying walking independence in hospitalized older adults. Phys Ther. 2010;90(11):1591–7.Gorea A. A refresher of the original Bloch’s Law paper (bloch, july 1885). i-Perception. 2015;6:4.Moss JD, Muth ER. Characteristics of head-mounted displays and their effects on Simulator sickness. Hum Factors. 2011;53(3):308–19.Draper MH, et al. Effects of image scale and system time delay on Simulator sickness within head-coupled virtual environments. Hum Factors. 2001;43(1):129–46.Fujisaki W. Effects of delayed visual feedback on grooved pegboard test performance. Front Psychol. 2012;3:61.Keshner EA, et al. Augmenting sensory-motor conflict promotes adaptation of postural behaviors in a virtual environment. Conf Proc IEEE Eng Med Biol Soc. 2011;2011:1379–82.Slaboda JC, Keshner EA. Reorientation to vertical modulated by combined support surface tilt and virtual visual flow in healthy elders and adults with stroke. J Neurol. 2012;259(12):2664–72.Tossavainen T. Comparison of CAVE and HMD for visual stimulation in postural control research. Stud Health Technol Inform. 2004;98:385–7.Akiduki H, et al. Visual-vestibular conflict induced by virtual reality in humans. Neurosci Lett. 2003;340(3):197–200.Duh HBL, et al. Effects of field of view on balance in an immersive environment. In: Virtual Reality, 2001. Proceedings. IEEE. 2001.Krijn M, et al. Treatment of acrophobia in virtual reality: the role of immersion and presence. Behav Res Ther. 2004;42(2):229–39.Mania K, Chalmers A. The effects of levels of immersion on memory and presence in virtual environments: a reality centered approach. Cyberpsychol Behav. 2001;4(2):247–64.Gorini A, et al. The role of immersion and narrative in mediated presence: the virtual hospital experience. Cyberpsychol Behav Soc Netw. 2011;14(3):99–105.Fromberger P, et al. Virtual viewing time: the relationship between presence and sexual interest in androphilic and gynephilic Men. PLoS One. 2015;10(5), e0127156.Slater M, et al. Visual realism enhances realistic response in an immersive virtual environment. IEEE Comput Graph Appl. 2009;29(3):76–84.Nir-Hadad SY, et al. A virtual shopping task for the assessment of executive functions: Validity for people with stroke. Neuropsychol Rehabil. 2015;11:1–26. doi: 10.1080/09602011.2015.1109523 .Vasilyeva M, Lourenco SF. Development of spatial cognition. Wiley Interdiscip Rev Cogn Sci. 2012;3(3):349–62.Banakou D, Groten R, Slater M. Illusory ownership of a virtual child body causes overestimation of object sizes and implicit attitude changes. Proc Natl Acad Sci U S A. 2013;110(31):12846–51.Yee N, Bailenson JN, Ducheneaut N. The proteus effect: implications of transformed digital self-representation on online and offline behavior. Commun Res. 2009;36(2):285–312.Baylor AL. Promoting motivation with virtual agents and avatars: role of visual presence and appearance. Philos Trans R Soc Lond B Biol Sci. 2009;364(1535):3559–65.Clemente M, et al. Assessment of the influence of navigation control and screen size on the sense of presence in virtual reality using EEG. Expert Sys App. 2014;41(4, Part 2):1584–92.Clemente M, et al. An fMRI study to analyze neural correlates of presence during virtual reality experiences. 2013. Interacting with Computers

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

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    Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research
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