95 research outputs found

    Experimental and Numerical Study on the Semi-Closed Loop Control of a Planar Parallel Robot Manipulator

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    This paper implements the model predictive control to fulfill the position control of a 3-DOF 3-RRR planar parallel manipulator. The research work covers experimental and numerical studies. First, an experimental hardware-in-the-loop system to control the manipulator is constructed. The manipulator is driven by three DC motors, and each motor has an encoder to measure the rotating angles of the motors. The entire system is designed as a semiclosed-loop control system. The controller receives the encoder signals as inputs to produce signals driving the motors. Secondly, the motor parameters are obtained by system identification, and the controllers are designed based on these parameters. Finally, the numerical simulations are performed by incorporating the manipulator kinematics and the motor dynamics; the results are compared with those from the experiments. Both results show that they are in good agreement at steady state. There are two main contributions in this paper. One is the application of the model predictive control to the planar parallel manipulator, and the other one is to overcome the effects of the uncertainties of the DC motors and the performance of the position control due to the dynamic behavior of the manipulator

    MENTOR: Multilingual tExt detectioN TOward leaRning by analogy

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    Text detection is frequently used in vision-based mobile robots when they need to interpret texts in their surroundings to perform a given task. For instance, delivery robots in multilingual cities need to be capable of doing multilingual text detection so that the robots can read traffic signs and road markings. Moreover, the target languages change from region to region, implying the need of efficiently re-training the models to recognize the novel/new languages. However, collecting and labeling training data for novel languages are cumbersome, and the efforts to re-train an existing/trained text detector are considerable. Even worse, such a routine would repeat whenever a novel language appears. This motivates us to propose a new problem setting for tackling the aforementioned challenges in a more efficient way: "We ask for a generalizable multilingual text detection framework to detect and identify both seen and unseen language regions inside scene images without the requirement of collecting supervised training data for unseen languages as well as model re-training". To this end, we propose "MENTOR", the first work to realize a learning strategy between zero-shot learning and few-shot learning for multilingual scene text detection.Comment: 8 pages, 4 figures, published to IROS 202

    Lasing on nonlinear localized waves in curved geometry

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    The use of geometrical constraints opens many new perspectives in photonics and in fundamental studies of nonlinear waves. By implementing surface structures in vertical cavity surface emitting lasers as manifolds for curved space, we experimentally study the impacts of geometrical constraints on nonlinear wave localization. We observe localized waves pinned to the maximal curvature in an elliptical-ring, and confirm the reduction in the localization length of waves by measuring near and far field patterns, as well as the corresponding dispersion relation. Theoretically, analyses based on a dissipative model with a parabola curve give good agreement remarkably to experimental measurement on the transition from delocalized to localized waves. The introduction of curved geometry allows to control and design lasing modes in the nonlinear regime.Comment: 6 pages, 6 figure

    The association between socioeconomic status and traditional chinese medicine use among children in Taiwan

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    <p>Abstract</p> <p>Background</p> <p>Traditional Chinese medicine (TCM) utilization is common in Asian countries. Limited studies are available on the socioeconomic status (SES) associated with TCM use among the pediatric population. We report on the association between SES and TCM use among children and adolescents in Taiwan.</p> <p>Methods</p> <p>A National Health Interview Survey was conducted in Taiwan in 2001 that included 5,971 children and adolescents. We assessed the children's SES using the head of household's education, occupation and income. This information was used to calculate pediatric SES scores, which in turn were divided into quartiles. Children and adolescents who visited TCM in the past month were defined as TCM users.</p> <p>Results</p> <p>Compared to children in the second SES quartile, children in the fourth SES quartile had a higher average number of TCM visits (0.12 vs. 0.06 visits, p = 0.027) and higher TCM use prevalence (5.0% vs. 3.6%, p = 0.024) within the past month. The adjusted odds ratio (OR) for TCM use was higher for children in the fourth SES quartile than for those in the first SES quartile (OR 1.49; 95% confidence interval [CI] 1.02-2.17). The corresponding OR was 2.17 for girls (95% CI 1.24-3.78). The highest-SES girls (aged 10-18 years) were most likely to visit TCM practices (OR 2.47; 95% CI 1.25-4.90).</p> <p>Conclusions</p> <p>Children and adolescents with high SES were more likely to use TCM and especially girls aged 10-18 years. Our findings point to the high use of complementary and alternative medicine among children and adolescents.</p

    Spintronics: Fundamentals and applications

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    Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio

    Joint Recognition of Multiple Concurrent Activities using Factorial Conditional Random Fields

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    Recognizing patterns of human activities is an important enabling technology for building intelligent home environments. Existing approaches to activity recognition often focus on mutually exclusive activities only. In reality, people routinely carry out multiple concurrent activities. It is therefore necessary to model the co-temporal relationships among activities. In this paper, we propose using Factorial Conditional Random Fields (FCRFs) for recognition of multiple concurrent activities. We designed experiments to compare our FCRFs model with Linear Chain Condition Random Fields (LCRFs) in learning and performing inference with the MIT House n data set, which contains annotated data collected from multiple sensors in a real living environment. The experimental results show that FCRFs can effectively improve the recognition accuracy up to 10 % in the presence of multiple concurrent activities. 1

    Drug reaction with eosinophilia and systemic symptoms: A drug-induced hypersensitivity syndrome with variable clinical features

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    Drug reaction with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS) involves a unique and severe adverse drug reaction. Patients present with fever, rash, lymphadenopathy, hematological abnormalities, systemic illness, and may suffer from prolonged courses. Although the precise pathogenesis of DRESS/DIHS is not fully understood, it is widely considered to be an immunological reaction to a drug or drug metabolites. In this review article, we discuss the historical aspects of nosology, variable clinical and histopathological features, advantages and disadvantages of using an international Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) and Japanese DIHS criteria, pathogenesis, treatment, and long-term sequelae of DRESS/DIHS. Early recognition of this syndrome, withdrawal of suspected culprit drugs, and adequate supportive care are mainstays of improving patient prognosis and reducing morbidities and mortality. Moreover, some DRESS/DIHS patients may develop long-term sequelae, especially autoimmune diseases and end organ failure. Physicians should be aware of these possibilities in patients after DRESS/DIHS and cautiously follow-up symptoms and laboratory tests for early detection of these sequelae

    Ante-grade intramedullary nailing for the treatment of humeral shaft metastatic bone tumor

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    Background: The surgical treatment of humeral fractures is controversial, and conservative therapy of pathologic fractures is not recommended. Materials and Methods: We performed a retrospective study of eight patients who had pathological humeral shaft fractures. All fractures were stabilized with ante-grade intramedullary nailing and wide resection of the tumor. Bone defects were filled with polymethylmethacrylate cement augmentation. Results: The mean operative time for the procedure was 160 min (range, 120-190 min), and the mean duration of hospitalization was 10.5 days (range, 5-15 days). Relief of pain was rated as good to excellent. There were no wound problems, deep infections, nerve palsies, or implant failures observed. X-ray studies demonstrated the improved stability of the humerus. Conclusion: Interlocking intramedullary nailing for pathological humeral shaft fractures provides immediate stability and can be accomplished with wide resection of tumor and bone defect augmentation with cement. Early return of functional status and pain relief greatly improved the patient′s quality of life
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