222 research outputs found

    Design and feasibility analysis of a novel auto hold system in hydrostatic transmission wheeled vehicle

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    Auto hold refers to vehicle’s function of automatic braking under shutdown condition and automatic relieving braking force when vehicle starts. This paper presents a concrete structure of the novel auto hold system of hydrostatic transmission wheeled vehicle, and deeply analyses the working mechanism and control method. To validate its feasibility, AMESim software is adopted to establish the simulation model of the auto hold system based on mathematical theories. By using the data of a certain comprehensive operation mode as input, the curve of braking force of the auto hold system is obtained through simulation. It can be known through analysis that the proposed auto hold system can realize rapid response and provides stable braking force under different road conditions. Finally, the feasibility of the proposed auto hold system is validated by comparing the simulation data with actual braking force required and the electronic vehicle parking technology. It turns out that the auto hold system can meet the requirements of all road conditions. Besides, it also can provide a fault tolerance range for real vehicle experiments, and it will not cause adverse impacts due to excessive parking brake force

    An optimal extension of Perelman's comparison theorem for quadrangles and its applications

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    In this paper we discuss an extension of Perelman's comparison for quadrangles. Among applications of this new comparison theorem, we study the equidistance evolution of hypersurfaces in Alexandrov spaces with non-negative curvature. We show that, in certain cases, the equidistance evolution of hypersurfaces become totally convex relative to a bigger sub-domain. An optimal extension of 2nd variational formula for geodesics by Petrunin will be derived for the case of non-negative curvature. In addition, we also introduced the generalized second fundament forms for subsets in Alexandrov spaces. Using this new notion, we will propose an approach to study two open problems in Alexandrov geometry.Comment: We corrected some inaccurate statements and definitions about development maps related to Corollary 2.4, based on Professor Stephanie Alexander's suggestion

    Compound Control of Electromagnetic Linear Actuator Based on Fuzzy Switching

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    Due to the motion control system of electromagnetic linear actuator (EMLA) is a nonlinear system with poor controllability, single control strategy has been difficult to meet the requirements of its control. A compound control strategy based on inverse system control (ISC) and proportional-integral (PI) is designed in this paper. Switching between two algorithms, which is based on the fuzzy rules, prevents the control algorithm to jitter and jump. System model is build under Matlab/Simulink to do simulation analysis. The designed controller is integrated into the system simulation model and the system software of digital signal processor (DSP) controller. Simulation and test results show that the compound control strategy using fuzzy switching rules achieves the smooth transition of two control algorithms, and the goal of any position location, and continuous adjustment in 0~4mm lift. Positioning accuracy is up to ± 0.02mm, while the response time is less than 10ms

    Coarse-grained lattice kinetic Monte Carlo simulation of systems of strongly interacting particles

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    A general approach is presented for spatially coarse-graining lattice kinetic Monte Carlo (LKMC) simulations of systems containing strongly interacting particles. While previous work has relied on approximations that are valid in the limit of weak interactions, here we show that it is possible to compute coarse-grained transition rates for strongly interacting systems without a large computational burden. A two-dimensional square lattice is employed on which a collection of (supersaturated) strongly interacting particles is allowed to reversibly evolve into clusters. A detailed analysis is presented of the various approximations applied in LKMC coarse graining, and a number of numerical closure rules are contrasted and compared. In each case, the overall cluster size distribution and individual cluster structures are used to assess the accuracy of the coarse-graining approach. The resulting closure approach is shown to provide an excellent coarse-grained representation of the systems considered in this study

    Arabidopsis Putative Deacetylase AtSRT2 Regulates Basal Defense by Suppressing PAD4, EDS5 and SID2 Expression

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    The silent information regulator protein (Sir2) and its homologs are NAD+-dependent deacetylase enzymes that play important roles in a variety of physiological processes. However, the functions of the Sir2 family in plants are poorly understood. Here, we report that Arabidopsis AtSRT2, a homolog of yeast Sir2, negatively regulates plant basal defense against the pathogen Pseudomonas syringae pv. tomato DC3000 (PstDC3000). In response to PstDC3000 infection, the expression of AtSRT2 was down-regulated in a salicylic acid (SA)-independent manner. In addition, knock-out of AtSRT2 (srt2) enhanced resistance against PstDC3000 and increased expression of pathogenesis-related gene 1 (PR1). Conversely, overexpression of AtSRT2 resulted in hypersusceptibility to PstDC3000 and impaired PR1 induction. Consistent with this phenotype, expression of PAD4, EDS5 and SID2, three essential genes in the SA biosynthesis pathway, were increased in the srt2 mutant and decreased in AtSRT2-overexpressing plants. Taken together, these results demonstrate that AtSRT2 is a negative regulator of basal defense, possibly by suppressing SA biosynthesis

    On-lattice kinetic Monte Carlo simulations of point defect aggregation in entropically influenced crystalline systems

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    An on-lattice kinetic Monte Carlo model of vacancy aggregation in crystalline silicon is parametrized using direct regression to evolution data from nonequilibrium molecular dynamics simulations. The approach bypasses the need to manually compute an energy barrier for each possible transition and leads to an excellent, robust representation of the molecular dynamics data. We show that the resulting lattice kinetic Monte Carlo model correctly captures the behavior of the real, continuous space system by properly accounting for continuous space entropic effects, which are often neglected in lattice-based models of atomistic processes. These contributions are particularly important at the high temperatures relevant to many steps in semiconductor materials processing

    The Role of Confucian Values in East Asian Development: Before and After the Financial Crisis

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    Asian Values provided a convincing cultural explanation for high economic hrowth in East Asia up until the recent economic crisis, without many of the social problems that are normally associated with rapid development, However, the Asian economic crisis has prompted a re-examination of Asian values. This paper argues that the positve aspects of Confucian values outweigh its minuses and that it is up to the East Asian economies to take steps to maximize its positive aspects, The paper also argues that its minuses and that it is up to the East Asian economies to take steps to maximize its positive aspects, The paper also argues that its Weakness coannot be entirely blamed for the Asian economic crisis and that given the overwhelming evidence of East Asia"s remarkable economic performance over a sustained period, the effects of Confucianism on economic development should not be overlooke

    Modified Logistic Regression Models Using Gene Coexpression and Clinical Features to Predict Prostate Cancer Progression

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    Predicting disease progression is one of the most challenging problems in prostate cancer research. Adding gene expression data to prediction models that are based on clinical features has been proposed to improve accuracy. In the current study, we applied a logistic regression (LR) model combining clinical features and gene co-expression data to improve the accuracy of the prediction of prostate cancer progression. The top-scoring pair (TSP) method was used to select genes for the model. The proposed models not only preserved the basic properties of the TSP algorithm but also incorporated the clinical features into the prognostic models. Based on the statistical inference with the iterative cross validation, we demonstrated that prediction LR models that included genes selected by the TSP method provided better predictions of prostate cancer progression than those using clinical variables only and/or those that included genes selected by the one-gene-at-a-time approach. Thus, we conclude that TSP selection is a useful tool for feature (and/or gene) selection to use in prognostic models and our model also provides an alternative for predicting prostate cancer progression

    Ginseng Total Saponins Reverse Corticosterone-Induced Changes in Depression-Like Behavior and Hippocampal Plasticity-Related Proteins by Interfering with GSK-3 β

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    This study aimed to explore the antidepressant mechanisms of ginseng total saponins (GTS) in the corticosterone-induced mouse depression model. In Experiment 1, GTS (50, 25, and 12.5 mg kg−1 d−1, intragastrically) were given for 3 weeks. In Experiment 2, the same doses of GTS were administrated after each corticosterone (20 mg kg−1 d−1, subcutaneously) injection for 22 days. In both experiments, mice underwent a forced swimming test and a tail suspension test on day 20 and day 21, respectively, and were sacrificed on day 22. Results of Experiment 1 revealed that GTS (50 and 25 mg kg−1 d−1) exhibited antidepressant activity and not statistically altered hippocampal protein levels of brain-derived neurotrophic factor (BDNF) and neurofilament light chain (NF-L). Results of Experiment 2 showed that GTS (50 and 25 mg kg−1 d−1) ameliorated depression-like behavior without normalizing hypercortisolism. The GTS treatments reversed the corticosterone-induced changes in mRNA levels of BDNF and NF-L, and protein levels of BDNF NF-L, phosphor-cAMP response element-binding protein (Ser133), and phosphor-glycogen synthase kinase-3β (Ser9) in the hippocampus. These findings imply that the effect of GTS on corticosterone-induced depression-like behavior may be mediated partly through interfering with hippocampal GSK-3β-CREB signaling pathway and reversing decrease of some plasticity-related proteins
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