41 research outputs found

    Behavior-Based Fuzzy Control for Mobile Robot Navigation

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    A new behavior-based fuzzy control method for mobile robot navigation is presented. It is based on behavioral architecture which can deal with uncertainties in unknown environments and has the ability to accommodate different behaviors. Basic behaviors are controlled by specific fuzzy logic controllers, respectively. The proposed approach qualifies for driving a robot to reach a target while avoiding obstacles in the environment. Simulation and experiments are performed to verify the correctness and feasibility of the proposed method

    Academic-practice partnerships in evidence-based nursing practice: a scoping review protocol

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    Introduction Academic-practice partnerships are a promising strategy that could strengthen the promotion and innovation of evidence-based nursing practice (EBNP). However, there is little evidence of how academic and clinical institutions and individuals should collaborate in each process of EBNP and the factors that influence academic-practice partnerships in EBNP. There is a pressing need to explore the extent of the literature on academic-practice partnerships in EBNP, as well as to classify, compare and summarise the results or opinions obtained from various types of literature to identify both existing knowledge and gaps in the research.Methods and analysis The scoping review will be conducted following the methodological guidelines provided by the JBI. The scoping review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Seven databases, including the Cochrane Library, PubMed, Web of Science, CINAHL, EMBASE, SCOPUS, Educational Resource Information Center and two Chinese databases (ie, CNKI and WANFANG DATA), will be searched. The grey literature will also be searched using the American Association of Colleges of Nursing, American Nurses Association, Open Grey, Grey Literature Report and the official website of JBI. The literature screening and data extraction will be conducted independently by two researchers. A third researcher will be involved when a consensus is needed.Ethics and dissemination Ethics approval is not required. The findings of the scoping review will be disseminated in a conference and a peer-reviewed journal.</p

    Hop: Heterogeneity-Aware Decentralized Training

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    Recent work has shown that decentralized algorithms can deliver superior performance over centralized ones in the context of machine learning. The two approaches, with the main difference residing in their distinct communication patterns, are both susceptible to performance degradation in heterogeneous environments. Although vigorous efforts have been devoted to supporting centralized algorithms against heterogeneity, little has been explored in decentralized algorithms regarding this problem. This paper proposes Hop, the first heterogeneity-aware decentralized training protocol. Based on a unique characteristic of decentralized training that we have identified, the iteration gap, we propose a queue-based synchronization mechanism that can efficiently implement backup workers and bounded staleness in the decentralized setting. To cope with deterministic slowdown, we propose skipping iterations so that the effect of slower workers is further mitigated. We build a prototype implementation of Hop on TensorFlow. The experiment results on CNN and SVM show significant speedup over standard decentralized training in heterogeneous settings

    ROS-scavenging hydrogel as protective carrier to regulate stem cells activity and promote osteointegration of 3D printed porous titanium prosthesis in osteoporosis

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    Stem cell-based therapy has drawn attention as an alternative option for promoting prosthetic osteointegration in osteoporosis by virtue of its unique characteristics. However, estrogen deficiency is the main mechanism of postmenopausal osteoporosis. Estrogen, as an effective antioxidant, deficienncy also results in the accumulation of reactive oxygen species (ROS) in the body, affecting the osteogenic differentiation of stem cells and the bone formation i osteoporosis. In this study, we prepared a ROS-scavenging hydrogel by crosslinking of epigallocatechin-3-gallate (EGCG), 3-acrylamido phenylboronic acid (APBA) and acrylamide. The engineered hydrogel can scavenge ROS efficiently, enabling it to be a cell carrier of bone marrow-derived mesenchymal stem cells (BMSCs) to protect delivered cells from ROS-mediated death and osteogenesis inhibition, favorably enhancing the tissue repair potential of stem cells. Further in vivo investigations seriously demonstrated that this ROS-scavenging hydrogel encapsulated with BMSCs can prominently promote osteointegration of 3D printed microporous titanium alloy prosthesis in osteoporosis, including scavenging accumulated ROS, inducing macrophages to polarize toward M2 phenotype, suppressing inflammatory cytokines expression, and improving osteogenesis related markers (e.g., ALP, Runx-2, COL-1, BSP, OCN, and OPN). This work provides a novel strategy for conquering the challenge of transplanted stem cells cannot fully function in the impaired microenvironment, and enhancing prosthetic osteointegration in osteoporosis

    Cooperative Search by Combining Simulated and Real Robots in a Swarm under the View of Multibody System Dynamics

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    This paper presents a new approach for cooperative search of a robot swarm. After modeling the robot, the mechanical Particle Swarm Optimization method is conducted based on physical robot properties. Benefiting from the effective localization and navigation by sensor data fusion, a mixed robot swarm which contains both simulated and real robots is then successfully used for searching a target cooperatively. With the promising results from experiments based on different scenarios, the feasibility, the interaction of real and simulated robots, the fault tolerance, and also the scalability of the proposed method are investigated

    A Chattering-Suppression Sliding Mode Controller for an Underwater Manipulator Using Time Delay Estimation

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    Underwater manipulators are pivotal in diverse applications, encompassing underwater pipeline repairs, salvage operations, and scientific sampling missions. However, attaining high-precision control mandates the establishment of precise mathematical models. Specifically, developing an accurate dynamic model for the underwater manipulator affixed to underwater robots proves exceptionally demanding, primarily attributed to the uncertainties arising from water currents and the perturbations induced by the vehicle’s motion. This paper presents a novel sliding mode controller with time delay estimation for the high-precision control of an underwater manipulator mounted on an underwater vehicle. The presented controller circumvents the requirement for an exact mathematical model of the underwater manipulator, enhancing its control precision even without detailed modeling information. Moreover, the proposed controller guarantees robustness against uncertain water flow disturbances, effectively preserving the performance of the underwater manipulator under challenging underwater conditions. The proposed controller comprises two key elements. Firstly, a time delay estimator is employed to estimate the system states using feedback from intentional time-delayed control inputs and a pre-designed matrix. Additionally, a specially designed reaching law is incorporated to reduce reaching time and prevent chattering in the sliding mode control. The controller offers several advantages, including easy implementation, insensitivity to model uncertainties, and robustness in the underwater environment. Simulations and experiments demonstrate the ability of the proposed controller to effectively mitigate disturbances, eliminate chattering, and ensure precise trajectory-tracking performance. The experiments are conducted on a fully self-developed 2-degree-of-freedom (2-DOF) underwater manipulator, showcasing the superiority of the proposed controller over other alternatives

    Dynamic Control and Disturbance Estimation of 3D Path Following for the Observation Class Underwater Remotely Operated Vehicle

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    This study addresses the question of 3D path following for the observation class underwater remotely operated vehicle. The dynamic model of the investigated remote operated vehicle is taken as a coupled multibody system composing of a flexible body and a rigid body. For precise control, the tether cable disturbance has been investigated as well via a dynamic model. Each element of the tethered cable even has been taken as an elastic body, and the waves and current disturbances have been taken into consideration. Based on the multibody system model, an adaptive backstepping sliding mode controller has been designed. To improve the controller's systematic robustness against disturbances, the sliding mode surface and adaptive control rule have been designed, too. Experiments have been performed in a tank, including the 3D path following controls of depth, heading, advance, sideway, polygon line, and spiral line. With current and wave disturbances having been taken into consideration, the tether effect has been analyzed, the efficacy and superiority of adaptive backstepping sliding mode control have been verified. It is further confirmed from the comparisons that the investigated method outperforms those S surface based controllers

    Instruments for measuring nursing research competence: a COSMIN-based scoping review

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    Abstract Aim The aim of this scoping review was to evaluate and summarise the measurement properties of nursing research competence instruments and provide a summary overview of the use of nursing research competence instruments. Background Increasing nursing research competence instruments have been developed. However, a systematic review and evaluation of nursing research competence instruments is lacking. Method This scoping review was conducted following the Joanna Briggs Institute updated methodology for scoping reviews and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Reviewers searched articles in Eight English databases and two Chinese databases between April 1st, 2022, and April 30th, 2022. An updated literature search was conducted between March 1st and March 4th, 2023. The literature screening and data extraction were conducted by two reviewers, independently. A third reviewer was involved when consensus was needed. The COnsensus-based Standards for the selection of health Measurement Instruments methodology was used to evaluate the methodological quality and measurement properties of the nursing research competence instruments. Results Ten studies involving eight nursing research competence instruments were included. None of the existing instruments have assessed all measurement properties. A total of 177 empirical studies have utilized a nursing research competence instrument with tested measurement properties. Conclusion ‘Self-evaluated Nursing Research Capacity of Questionnaire (refined)’ was identified as the most appropriate nursing research competence instrument in existing instruments. However, reviewers need to conduct further measurement properties studies on the existing nursing research competence instruments. Implications for the nursing policy This study could guide the selection of appropriate nursing research competence instruments which could help to evaluate the nursing research competence of nurses and inform the development of intervention plans to enhance nursing research competence
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