773 research outputs found

    Robust Control Synthesis and Verification for Wire-Borne Underactuated Brachiating Robots Using Sum-of-Squares Optimization

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    Control of wire-borne underactuated brachiating robots requires a robust feedback control design that can deal with dynamic uncertainties, actuator constraints and unmeasurable states. In this paper, we develop a robust feedback control for brachiating on flexible cables, building on previous work on optimal trajectory generation and time-varying LQR controller design. We propose a novel simplified model for approximation of the flexible cable dynamics, which enables inclusion of parametric model uncertainties in the system. We then use semidefinite programming (SDP) and sum-of-squares (SOS) optimization to synthesize a time-varying feedback control with formal robustness guarantees to account for model uncertainties and unmeasurable states in the system. Through simulation, hardware experiments and comparison with a time-varying LQR controller, it is shown that the proposed robust controller results in relatively large robust backward reachable sets and is able to reliably track a pre-generated optimal trajectory and achieve the desired brachiating motion in the presence of parametric model uncertainties, actuator limits, and unobservable states.Comment: 8 pages, 12 figures, 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS

    Cable Estimation-Based Control for Wire-Borne Underactuated Brachiating Robots: A Combined Direct-Indirect Adaptive Robust Approach

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    In this paper, we present an online adaptive robust control framework for underactuated brachiating robots traversing flexible cables. Since the dynamic model of a flexible body is unknown in practice, we propose an indirect adaptive estimation scheme to approximate the unknown dynamic effects of the flexible cable as an external force with parametric uncertainties. A boundary layer-based sliding mode control is then designed to compensate for the residual unmodeled dynamics and time-varying disturbances, in which the control gain is updated by an auxiliary direct adaptive control mechanism. Stability analysis and derivation of adaptation laws are carried out through a Lyapunov approach, which formally guarantees the stability and tracking performance of the robot-cable system. Simulation experiments and comparison with a baseline controller show that the combined direct-indirect adaptive robust control framework achieves reliable tracking performance and adaptive system identification, enabling the robot to traverse flexible cables in the presence of unmodeled dynamics, parametric uncertainties and unstructured disturbances.Comment: 8 pages, 8 figures, 2020 IEEE Conference on Decision and Control (CDC

    Cigarette Smoke Extract Stimulates Rat Pulmonary Artery Smooth Muscle Cell Proliferation via PKC-PDGFB Signaling

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    Accumulating evidence suggests a direct role for cigarette smoke in pulmonary vascular remodeling, which contributes to the development of pulmonary hypertension. However, the molecular mechanisms underlying this process remain poorly understood. Platelet-derived growth factor (PDGF) is a potential mitogen and chemoattractant implicated in several biological processes, including cell survival, proliferation, and migration. In this study, we investigated the effect of cigarette smoke extract (CSE) on cell proliferation of rat pulmonary artery smooth muscle cells (rPASMCs). We found that stimulation of rPASMCs with CSE significantly increased cell proliferation and promoted cell cycle progression from G1 phase to the S and G2 phases. CSE treatment also significantly upregulated the mRNA and protein levels of PDGFB and PDGFRβ. Our study also revealed that Rottlerin, an inhibitor of PKCδ signaling, prevented CSE-induced cell proliferation, attenuated the increase of S and G2 phase populations induced by CSE treatment, and downregulated PDGFB and PDGFRβ mRNA and protein levels in rPASMCs exposed to CSE. Collectively, our data demonstrated that CSE-induced cell proliferation of rPASMCs involved upregulation of the PKCδ-PDGFB pathway

    Impacts of recent cultivation on genetic diversity pattern of a medicinal plant, Scutellaria baicalensis (Lamiaceae)

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    <p>Abstract</p> <p>Background</p> <p>Cultivation of medicinal plants is not only a means for meeting current and future demands for large volume production of plant-based drug and herbal remedies, but also a means of relieving harvest pressure on wild populations. <it>Scutellaria baicalensis </it>Georgi (Huang-qin or Chinese skullcap) is a very important medicinal plant in China. Over the past several decades, wild resource of this species has suffered rapid declines and large-scale cultivation was initiated to meet the increasing demand for its root. However, the genetic impacts of recent cultivation on <it>S. baicalensis </it>have never been evaluated. In this study, the genetic diversity and genetic structure of 28 wild and 22 cultivated populations were estimated using three polymorphic chloroplast fragments. The objectives of this study are to provide baseline data for preserving genetic resource of <it>S. baicalensis </it>and to evaluate the genetic impacts of recent cultivation on medicinal plants, which may be instructive to future cultivation projects of traditional Chinese medicinal plants.</p> <p>Results</p> <p>Thirty-two haplotypes of <it>S. baicalensis </it>(HapA-Y and Hap1-7) were identified when three chloroplast spacers were combined. These haplotypes constituted a shallow gene tree without obvious clusters for cultivated populations, suggesting multiple origins of cultivated <it>S. baicalensis</it>. Cultivated populations (<it>h</it><sub>T </sub>= 0.832) maintained comparable genetic variation with wild populations (<it>h</it><sub>T </sub>= 0.888), indicating a slight genetic bottleneck due to multiple origins of cultivation. However, a substantial amount of rare alleles (10 out of 25 haplotypes within wild populations) lost during the course of <it>S. baicalensis </it>cultivation. The genetic differentiation for cultivated group (<it>G</it><sub>ST </sub>= 0.220) was significantly lower than that of wild group (<it>G</it><sub>ST </sub>= 0.701). Isolation by distance analysis showed that the effect of geographical isolation on genetic structure was significant in wild populations (<it>r </it>= 0.4346, <it>P </it>< 0.0010), but not in cultivated populations (<it>r = </it>0.0599, <it>P </it>= 0.2710). These genetic distribution patterns suggest that a transient cultivation history and the extensive seed change among different geographical areas during the course of <it>S. baicalensis </it>cultivation.</p> <p>Conclusions</p> <p>Although cultivated <it>S. baicalensis </it>maintains comparable genetic diversity relative to wild populations, recent cultivation has still imposed profound impacts on genetic diversity patterns of the cultivated <it>S. baicalensis </it>populations, i.e., the loss of rare alleles and homogenization of cultivated populations. This study suggests that conservation-by-cultivation is an effective means for protecting genetic resources of <it>S. baicalensis</it>, however, the wild resources still need to be protected <it>in situ </it>and the evolutionary consequences of extensive seed exchange mediated by human being should be monitored carefully.</p

    a comunicação como intervenção terapêutica de enfermagem

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    Mestrado, Enfermagem de Saúde Infantil e Pediatria, 2015, Escola Superior de Enfermagem de LisboaOs cuidados centrados na família (CCF) garantem a saúde e o bem-estar da criança e família numa relação de respeito e parceria. Assim, o apoio da família torna-se essencial para que a sua participação nos cuidados à criança seja uma realidade dentro dos CCF. As competências comunicacionais dos Enfermeiros são uma componente essencial dos CCF, como elemento de ligação numa equipa multidisciplinar e cuidadora da criança/família. À medida que a sua intervenção se desenvolve com novas competências, é importante que seja dada também relevância crescente à comunicação. Assim sendo, pretende-se aprofundar a temática das vivências e respostas dos pais perante a doença aguda do filho, tendo como objeto de estudo a comunicação como intervenção terapêutica de Enfermagem. Para tal, foi utilizado como metodologia a reflexão sobre e na prática, numa abordagem do Cuidar de Jean Watson, inserido no paradigma da transformação. Ao longo da experiência de estágio em diferentes contextos pediátricos foram desenvolvidas diversas atividades relacionadas com a problemática, destacando-se a criação de um Manual de Promoção de Saúde: Estratégia de Comunicação para a Saúde, Dossier Temático: A Comunicação Terapêutica com a Família da Criança Hospitalizada, uma norma de Guia Orientador de Boas Práticas no Processo de Comunicação Terapêutica com a Criança/Família que recorre ao Serviço de Urgência, inserida no Manual de Acolhimento do mesmo. Pode-se concluir que os Enfermeiros desenvolvem a comunicação como instrumento terapêutico na relação de parceria e de ajuda com a criança/família, na relação com grupos de ajuda mútua, nos momentos de educação para a saúde a ainda na formação das equipas de saúde, sendo o binómio gestão das emoções/gestão da informação transversal no cuidado humano

    Grid Enabled Geospatial Catalogue Web Service

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    Geospatial Catalogue Web Service is a vital service for sharing and interoperating volumes of distributed heterogeneous geospatial resources, such as data, services, applications, and their replicas over the web. Based on the Grid technology and the Open Geospatial Consortium (0GC) s Catalogue Service - Web Information Model, this paper proposes a new information model for Geospatial Catalogue Web Service, named as GCWS which can securely provides Grid-based publishing, managing and querying geospatial data and services, and the transparent access to the replica data and related services under the Grid environment. This information model integrates the information model of the Grid Replica Location Service (RLS)/Monitoring & Discovery Service (MDS) with the information model of OGC Catalogue Service (CSW), and refers to the geospatial data metadata standards from IS0 19115, FGDC and NASA EOS Core System and service metadata standards from IS0 191 19 to extend itself for expressing geospatial resources. Using GCWS, any valid geospatial user, who belongs to an authorized Virtual Organization (VO), can securely publish and manage geospatial resources, especially query on-demand data in the virtual community and get back it through the data-related services which provide functions such as subsetting, reformatting, reprojection etc. This work facilitates the geospatial resources sharing and interoperating under the Grid environment, and implements geospatial resources Grid enabled and Grid technologies geospatial enabled. It 2!so makes researcher to focus on science, 2nd not cn issues with computing ability, data locztic~, processir,g and management. GCWS also is a key component for workflow-based virtual geospatial data producing
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