4,180 research outputs found

    Polarization entangled state measurement on a chip

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    The emerging strategy to overcome the limitations of bulk quantum optics consists of taking advantage of the robustness and compactness achievable by the integrated waveguide technology. Here we report the realization of a directional coupler, fabricated by femtosecond laser waveguide writing, acting as an integrated beam splitter able to support polarization encoded qubits. This maskless and single step technique allows to realize circular transverse waveguide profiles able to support the propagation of Gaussian modes with any polarization state. Using this device, we demonstrate the quantum interference with polarization entangled states and singlet state projection.Comment: Revtex, 5+2 pages (with supplementary information), 4+1 figure

    A vision-based teleoperation system for robotic systems

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    Despite advances in robotic perception are increasing autonomous capabilities, human intelligence is still considered a necessity in unstructured or unpredictable environments. Hence, also according to the Industry 4.0 paradigm, humans and robots are encouraged to achieve mutual Human-Robot Interaction (HRI). HRI can be physical (pHRI) or not, depending on the assigned task. For example, when the robot is constrained in a dangerous environment or must handle hazardous materials, pHRI is not recommended. In these cases, robot teleoperation may be necessary. A teleoperation system concerns with the exploration and exploitation of spaces where the user presence is not allowed. Therefore, the operator needs to move the robot remotely. Although plenty of human-machine interfaces for teleoperation have been developed considering a mechanical device, vision-based interfaces do not require physical contact with external devices. This grants a more natural and intuitive interaction, which is reflected in task performance. Our proposed system is a novel robot teleoperation system that exploits RGB cameras, which are easy to use and commonly available on the market at a reduced price. A ROS-based framework has been developed to supply hand tracking and hand-gesture recognition features, exploiting the OpenPose software based on the Deep Learning framework Caffe. This, in combination with the ease of availability of an RGB camera, leads the framework to be strongly open-source-oriented and highly replicable on all ROS-based platforms. It is worth noting that the system does not include the Z-axis control in this first version. This is due to the high precision and sensitivity required to robustly control the third axis, a precision that 3D vision systems are not able to provide unless very expensive devices are adopted. Our aim is to further develop the system to include the third axis control in a future release

    A gesture-based robot program building software

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    With the advent of intelligent systems, industrial workstations and working areas have undergone a revolution. The increased need for automation is satisfied using high-performance industrial robots in fully automated workstations. In the manufacturing industry, sophisticated tasks still require human intervention in completely manual workstations, even if at a slower production rate. To improve the efficiency of manual workstations, Collaborative Robots (Co-Bots) have been designed as part of the Industry 4.0 paradigm. These robots collaborate with humans in safe environments to support the workers in their tasks, thus achieving higher production rates compared to completely manual workstations. The key factor is that their adoption relieves humans from stressful and heavy operations, decreasing job-related health issues. The drawback of Co-Bots stands in their design: to work side-by-side with humans they must guarantee safety; thus, they have very strict limitations on their forces and velocities, which limits their efficiency, especially when performing non-trivial tasks. To overcome these limitations, our idea is to design Meta-Collaborative workstations (MCWs), where the robot can operate behind a safety cage, either physical or virtual, and the operator can interact with the robot, either industrial or Collaborative, by means of the same communication channel. Our proposed system has been developed to easily build robot programs purposely designed for MCWs, based on (i) the recognition of hand gestures (using a vision-based communication channel) and (ii) ROS to carry out communication with the robot

    Evaluation of the disciplinary competences of the students of the Bachelor's degree in Nursing at 'Sapienza' University of Rome through the TECO: A cross-sectional study

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    The objective of the study is to evaluate whether the TECO-D is a useful tool for measuring the skills acquired by students during three years of the nursing bachelor's degree course at the 'Sapienza' University of Rome. The sample was recruited between January and April 2018. The distribution of the scores for the TECO-D shows an increasing average (standard deviation) from 177.3 ± 28 in the first year up to 214.1 ± 18.5 for graduating students. The test is comprehensive by sampling all relevant disciplines in a curriculum, usually determined by a fixed blueprint. The evaluation of the single macro areas showed statistically significant data reflecting increasing knowledge regarding the progression of the skills. Because of this, we can say that the TECO-D is a great tool for determining student's knowledge in order to evaluate study programs

    Engineering a C-Phase quantum gate: optical design and experimental realization

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    A two qubit quantum gate, namely the C-Phase, has been realized by exploiting the longitudinal momentum (i.e. the optical path) degree of freedom of a single photon. The experimental setup used to engineer this quantum gate represents an advanced version of the high stability closed-loop interferometric setup adopted to generate and characterize 2-photon 4-qubit Phased Dicke states. Some experimental results, dealing with the characterization of multipartite entanglement of the Phased Dicke states are also discussed in detail.Comment: accepted for publication on EPJ

    Validation of a smart mirror for gesture recognition in gym training performed by a vision-based deep learning system

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    This paper illustrates the development and validation of a smart mirror for sports training. The application is based on the skeletonization algorithm MediaPipe and runs on an embedded device Nvidia Jetson Nano equipped with two fisheye cameras. The software has been evaluated considering the exercise biceps curl. The elbow angle has been measured by both MediaPipe and the motion capture system BTS (ground truth), and the resulting values have been compared to determine angle uncertainty, residual errors, and intra-subject and inter-subject repeatability. The uncertainty of the joints’ estimation and the quality of the image captured by the cameras reflect on the final uncertainty of the indicator over time, highlighting the areas of improvement for further development

    Photoproduction of h_c

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    Using the NRQCD factorization formalism, we calculate the total cross section for the photoproduction of h_c mesons. We include color-octet and color-singlet mechanisms as well as next-to-leading order perturbative QCD corrections. The theoretical prediction depends on two nonperturbative matrix elements that are not well determined from existing data on charmonium production. For reasonable values of these matrix elements, the cross section is large enough that the h_c may be observable at the E831 experiment and at the HERA experiments.Comment: Revtex file 8 pages, 1 figure. Macros needed: epsf,floats,rotate Minor typos changed, and reference added. Version to be published in Phys.Rev.

    Differences in osteoimmunological biomarkers predictive of psoriatic arthritis among a large Italian cohort of psoriatic patients

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    (1) Background: In literature it is reported that 20\u201330% of psoriatic patients evolve to psoriatic arthritis over time. Currently, no specific biochemical markers can either predict progression to psoriatic arthritis or response to therapies. This study aimed to identify osteoimmunological markers applicable to clinical practice, giving a quantitative tool for evaluating pathological status and, eventually, to provide prognostic support in diagnosis. (2) Methods: Soluble (serum) bone and cartilage markers were quantified in 50 patients with only psoriasis, 50 psoriatic patients with psoriatic arthritis, and 20 healthy controls by means of multiplex and enzyme-linked immunoassays. (3) Results: Differences in the concentrations of matrix metalloproteases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), receptor activator of nuclear factor kappa-B-ligand (RANK-L), procollagen type I N propeptide (PINP), C-terminal telopeptide of type I collagen (CTx-I), dickkopf-related protein 1 (DKK1), and sclerostin (SOST) distinguished healthy controls from psoriasis and psoriatic arthritis patients. We found that MMP2, MMP12, MMP13, TIMP2, and TIMP4 distinguished psoriasis from psoriatic arthritis patients undergoing a systemic treatment, with a good diagnostic accuracy (Area under the ROC Curve (AUC) > 0.7). Then, chitinase-3-like protein 1 (CHI3L1) and MMP10 distinguished psoriasis from psoriatic arthritis not undergoing systemic therapy and, in the presence of onychopathy, MMP8 levels were higher in psoriasis than in psoriatic arthritis. However, in these latter cases, the diagnostic accuracy of the identified biomarkers was low (0.5 < AUC < 0.7). (4) Conclusions. By highlighting never exploited differences, the wide osteoimmunological biomarkers panel provides a novel clue to the development of diagnostic paths in psoriasis and psoriasis-associated arthropathic disease

    The Origin of Separable States and Separability Criteria from Entanglement-breaking Channels

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    In this paper, we show that an arbitrary separable state can be the output of a certain entanglement-breaking channel corresponding exactly to the input of a maximally entangled state. A necessary and sufficient separability criterion and some sufficient separability criteria from entanglement-breaking channels are given.Comment: EBCs with trace-preserving and EBCs without trace-preserving are separately discusse
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