5,215 research outputs found

    Distributed leader following of an active leader for linear heterogeneous multi-agent systems

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    This paper considers a leader-following problem for a group of heterogeneous linear time invariant (LTI) followers that are interacting over a directed acyclic graph. Only a subset of the followers has access to the state of the leader in specific sampling times. The dynamics of the leader that generates its sampled states is unknown to the followers. For interaction topologies in which the leader is a global sink in the graph, we propose a distributed algorithm that allows the followers to arrive at the sampled state of the leader by the time the next sample arrives. Our algorithm is a practical solution for a leader-following problem when there is no information available about the state of the leader except its instantaneous value at the sampling times. Our algorithm also allows the followers to track the sampled state of the leader with a locally chosen offset that can be time-varying. When the followers are mobile agents whose state or part of their state is their position vector, the offset mechanism can be used to enable the followers to form a transnational invariant formation about the sampled state of the leader. We prove that the control input of the followers to take them from one sampled state to the next one is minimum energy. We also show in case of the homogeneous followers, after the first sampling epoch the states and inputs of all the followers are synchronized with each other. Numerical examples demonstrate our results

    Identification of a novel nuclear export sequence of OREBP / TonEBP / NFAT5 that controls cytoplasmic localization

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    Waste reduction and recycling strategies for the in-flight services in the airline industry

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    Author name used in this publication: X. D. LiAuthor name used in this publication: S. C. Lee2002-2003 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Soil-Structure Interaction on the Response of Jacket Type Offshore Wind Turbine

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    Jacket structures are still at the early stage of their development for use in the offshore wind industry. The aim of this paper is to investigate the effect of the soil-structure interaction on the response of an offshore wind turbine with a jacket-type foundation. For this purpose, two different models of flexible foundation-the p-y model and the p-y model considering pile groups effect-are employed to compare the dynamic responses with the fixed-base model. The modal analysis and the coupled dynamic analysis are carried out under deterministic and stochastic conditions. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the loads of the offshore wind turbine structure well. It is suggested that during fatigue analysis the pile group effect should be considered for the jacket foundation.None1174Ysciescopu

    MFV Reductions of MSSM Parameter Space

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    The 100+ free parameters of the minimal supersymmetric standard model (MSSM) make it computationally difficult to compare systematically with data, motivating the study of specific parameter reductions such as the cMSSM and pMSSM. Here we instead study the reductions of parameter space implied by using minimal flavour violation (MFV) to organise the R-parity conserving MSSM, with a view towards systematically building in constraints on flavour-violating physics. Within this framework the space of parameters is reduced by expanding soft supersymmetry-breaking terms in powers of the Cabibbo angle, leading to a 24-, 30- or 42-parameter framework (which we call MSSM-24, MSSM-30, and MSSM-42 respectively), depending on the order kept in the expansion. We provide a Bayesian global fit to data of the MSSM-30 parameter set to show that this is manageable with current tools. We compare the MFV reductions to the 19-parameter pMSSM choice and show that the pMSSM is not contained as a subset. The MSSM-30 analysis favours a relatively lighter TeV-scale pseudoscalar Higgs boson and tanβ10\tan \beta \sim 10 with multi-TeV sparticles.Comment: 2nd version, minor comments and references added, accepted for publication in JHE

    Serum levels of WNT1-inducible signaling pathway protein-1 (WISP-1): a noninvasive biomarker of renal fibrosis in subjects with chronic kidney disease

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    WNT1-inducible signaling pathway protein-1 (WISP-1) is an extracellular matrix-related protein that plays multiple roles in cellular physiology and pathology. Accumulating evidence shows that WISP-1 is involved in the process underlying fibrotic diseases. However, the correlation between WISP-1 and renal fibrosis is unknown. In this study, we hypothesized that WISP-1 levels might be correlated with renal fibrosis and could be used as a noninvasive biomarker to screen for renal fibrosis in patients with chronic kidney disease (CKD). We first measured the WISP-1 expression levels using a transforming growth factor-β (TGF-β)-induced renal fibrosis tubular epithelial cell (TEC) model and a mouse model of obstructive nephropathy. We then evaluated the correlation between serum WISP-1 levels and fibrosis scores in biopsy-proven renal fibrosis of patients with CKD. Based on the findings from both in vivo and in vitro studies, the levels of WISP-1 and fibrotic parameters (collagen I, fibronectin and α-smooth muscle actin) were significantly increased in the fibrotic models. Consistently, patients with focal proliferative IgA nephropathy, focal segmental glomerular sclerosis and diabetic nephropathy displayed markedly elevated serum WISP-1 levels and fibrosis scores of renal biopsies compared with normal subjects and patients with minimal change disease (P<0.05). Importantly, the serum WISP-1 levels were positively correlated with fibrosis scores in the renal biopsies of these patients (r=0.475, P=0.0001). Thus, serum WISP-1 levels may be used as a potential noninvasive biomarker of renal fibrosis in patients with CKD.published_or_final_versio

    Patient complexity and genotype-phenotype correlations in biliary atresia: a cross-sectional analysis

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