3,434 research outputs found

    A Descriptive Model of Robot Team and the Dynamic Evolution of Robot Team Cooperation

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    At present, the research on robot team cooperation is still in qualitative analysis phase and lacks the description model that can quantitatively describe the dynamical evolution of team cooperative relationships with constantly changeable task demand in Multi-robot field. First this paper whole and static describes organization model HWROM of robot team, then uses Markov course and Bayesian theorem for reference, dynamical describes the team cooperative relationships building. Finally from cooperative entity layer, ability layer and relative layer we research team formation and cooperative mechanism, and discuss how to optimize relative action sets during the evolution. The dynamic evolution model of robot team and cooperative relationships between robot teams proposed and described in this paper can not only generalize the robot team as a whole, but also depict the dynamic evolving process quantitatively. Users can also make the prediction of the cooperative relationship and the action of the robot team encountering new demands based on this model. Journal web page & a lot of robotic related papers www.ars-journal.co

    Deposition morphology of non-homogeneous debris flow and its energy characteristics

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    Non-homogeneous two-phase debris flows are widely found in the western mountainous regions of China. To investigate the characteristics of the debris flow deposition process related to the morphology and extent of the debris fan, a series of physical experiments were carried out using an experimental flume. Some useful relationships were obtained to link the flow velocity with the geometric characteristics of deposition morphology and the corresponding area or volume. Based on these, some expressions about energy dissipation process in both the transport-deposition zone and deposition zone are presented, and improved equations describing solid-liquid two-phase energy transformations in the specific deposition zone are also established. These results provide a basis for further investigating the underlying mechanisms of non-homogeneous debris flows, based upon which effective disaster control measures can be undertaken

    Experimental study on flow resistance over rigid vegetated channel

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    Vegetation is an important part of the ecological channel, and flow structure over vegetation in ecological channel is rather complex. The vegetation resistance to flow is affected by many factors, and there is still no general calculation method to express it. Thus, it is necessary to explore the mechanism of flow resistance over vegetation in open channel. In this paper, the rigid cylindrical sticks arranged in the open channel were used to simulate the stems of non-submerged vegetation in order to investigate the effects of vegetation on the flow. Through theoretical analysis and experimental verification, it shows the form drag caused by vegetation is closely related to the vortex volume created by vegetation. In addition, the total resistance of vegetated channel can be determined by two methods based on vegetation density and flow resistance partitioning, respectively, and both of them are verified by the experimental results. What\u27s more, for rigid vegetation, the drag coefficient is closely related to vegetation density, spacing between vegetation patches and the Reynolds number. The empirical formula among them was established through the experimental results

    Existence of Monotone Positive Solution of Neutral Partial Difference Equation

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    AbstractThis paper is concerned with a class of neutral partial difference equations. The conditions for the existence of monotone eventually positive solutions are established which improve and extend some of the criteria existing in the literature. Comparison theorems are also derived. Results are obtained on the existence of a monotone eventually positive solution of dual equation

    S-allylcysteine Improves Blood Flow Recovery and Prevents Ischemic Injury by Augmenting Neovasculogenesis.

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    Studies suggest that a low level of circulating human endothelial progenitor cells (EPCs) is a risk factor for ischemic injury and coronary artery disease (CAD). Consumption of S-allylcysteine (SAC) is known to prevent CAD. However, the protective effects of SAC on the ischemic injury are not yet clear. In this study, we examined whether SAC could improve blood flow recovery in ischemic tissues through EPC-mediated neovasculogenesis. The results demonstrate that SAC significantly enhances the neovasculogenesis of EPCs in vitro. The molecular mechanisms for SAC enhancement of neovasculogenesis include the activation of Akt/endothelial nitric oxide synthase signaling cascades. SAC increased the expression of c-kit, β-catenin, cyclin D1, and Cyclin-dependent kinase 4 (CDK4) proteins in EPCs. Daily intake of SAC at dosages of 0.2 and 2 mg/kg body weight significantly enhanced c-kit protein levels in vivo. We conclude that dietary consumption of SAC improves blood flow recovery and prevents ischemic injury by inducing neovasculogenesis in experimental models
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