5,349 research outputs found

    Bounded perturbation resilience of extragradient-type methods and their applications

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    In this paper we study the bounded perturbation resilience of the extragradient and the subgradient extragradient methods for solving variational inequality (VI) problem in real Hilbert spaces. This is an important property of algorithms which guarantees the convergence of the scheme under summable errors, meaning that an inexact version of the methods can also be considered. Moreover, once an algorithm is proved to be bounded perturbation resilience, superiorizion can be used, and this allows flexibility in choosing the bounded perturbations in order to obtain a superior solution, as well explained in the paper. We also discuss some inertial extragradient methods. Under mild and standard assumptions of monotonicity and Lipschitz continuity of the VI's associated mapping, convergence of the perturbed extragradient and subgradient extragradient methods is proved. In addition we show that the perturbed algorithms converges at the rate of O(1/t)O(1/t). Numerical illustrations are given to demonstrate the performances of the algorithms.Comment: Accepted for publication in The Journal of Inequalities and Applications. arXiv admin note: text overlap with arXiv:1711.01936 and text overlap with arXiv:1507.07302 by other author

    A role of corazonin receptor in larval-pupal transition and pupariation in the oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

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    Corazonin (Crz) is a neuropeptide hormone, but also a neuropeptide modulator that is internally released within the CNS, and it has a widespread distribution in insects with diverse physiological functions. Here, we identified and cloned the cDNAs of Bactrocera dorsalis that encode Crz and its receptor CrzR. Mature BdCrz has 11 residues with a unique Ser11 substitution (instead of the typical Asn) and a His in the evolutionary variable position 7. The BdCrzR cDNA encodes a putative protein of 608 amino acids with 7 putative transmembrane domains, typical for the structure of G-protein-coupled receptors. When expressed in Chinese hamster ovary (CHO) cells, the BdCrzR exhibited a high sensitivity and selectivity for Crz (EC50 approximate to 52.5 nM). With qPCR, the developmental stage and tissue-specific expression profiles in B. dorsalis demonstrated that both BdCrz and BdCrzR were highly expressed in the larval stage, and BdCrzR peaked in 2-day-old 3rd-instar larvae, suggesting that the BdCrzR may play an important role in the larval-pupal transition behavior. Immunochemical localization confirmed the production of Crz in the central nervous system (CNS), specifically by a group of three neurons in the dorso-lateral protocerebrum and eight pairs of lateral neurons in the ventral nerve cord. qPCR analysis located the BdCrzR in both the CNS and epitracheal gland, containing the Inka cells. Importantly, dsRNA-BdCrzR-mediated gene-silencing caused a delay in larval-pupal transition and pupariation, and this phenomenon agreed with a delayed expression of tyrosine hydroxylase and dopa-decarboxylase genes. We speculate that CrzR-silencing blocked dopamine synthesis, resulting in the inhibition of pupariation and cuticular melanization. Finally, injection of Crz in head-ligated larvae could rescue the effects. These findings provide a new insight into the roles of Crz signaling pathway components in B. dorsalis and support an important role of CrzR in larval-pupal transition and pupariation behavior

    Eco-driving for Electric Connected Vehicles at Signalized Intersections: A Parameterized Reinforcement Learning approach

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    This paper proposes an eco-driving framework for electric connected vehicles (CVs) based on reinforcement learning (RL) to improve vehicle energy efficiency at signalized intersections. The vehicle agent is specified by integrating the model-based car-following policy, lane-changing policy, and the RL policy, to ensure safe operation of a CV. Subsequently, a Markov Decision Process (MDP) is formulated, which enables the vehicle to perform longitudinal control and lateral decisions, jointly optimizing the car-following and lane-changing behaviors of the CVs in the vicinity of intersections. Then, the hybrid action space is parameterized as a hierarchical structure and thereby trains the agents with two-dimensional motion patterns in a dynamic traffic environment. Finally, our proposed methods are evaluated in SUMO software from both a single-vehicle-based perspective and a flow-based perspective. The results show that our strategy can significantly reduce energy consumption by learning proper action schemes without any interruption of other human-driven vehicles (HDVs)

    Progressive amorphization of GeSbTe phase-change material under electron beam irradiation

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    Fast and reversible phase transitions in chalcogenide phase-change materials (PCMs), in particular, Ge-Sb-Te compounds, are not only of fundamental interests, but also make PCMs based random access memory (PRAM) a leading candidate for non-volatile memory and neuromorphic computing devices. To RESET the memory cell, crystalline Ge-Sb-Te has to undergo phase transitions firstly to a liquid state and then to an amorphous state, corresponding to an abrupt change in electrical resistance. In this work, we demonstrate a progressive amorphization process in GeSb2Te4 thin films under electron beam irradiation on transmission electron microscope (TEM). Melting is shown to be completely absent by the in situ TEM experiments. The progressive amorphization process resembles closely the cumulative crystallization process that accompanies a continuous change in electrical resistance. Our work suggests that if displacement forces can be implemented properly, it should be possible to emulate symmetric neuronal dynamics by using PCMs

    Determination and pharmacokinetic study of catechin in rat plasma by HPLC

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    AbstractA high performance liquid chromatographic method was developed and validated for the quantitative determination of catechin in rat plasma and its pharmacokinetic study after intragastric administration of Catechu and Xiongdanjiangre Wan into SD rats. Plasma samples were prepared by protein precipitation using methanol–5% aqueous zinc sulfate (70:30, v/v) as precipitant. Chromatographic separation was achieved on Hypersil C18 column (250mm×4.6mm, 10μm) with acetonitrile–water–triethylamine (6:94:0.3, v/v/v, pH 4.0±0.1, adjusted with phosphoric acid) as mobile phase, followed by a UV detection at 207nm. Good linearity was obtained over the range of 0.143–7.15mg/L of catechin, with correlation coefficient of 0.9992. The method was simple, sensitive, accurate and reproducible and has been successfully applied to the pharmacokinetic study of catechin in rat plasma

    Randomized and Efficient Authentication in Mobile Environments

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    In a mobile environment, a number of users act as a network nodes and communicate with one another to acquire location based information and services. This emerging paradigm has opened up new business opportunities and enables numerous applications such as road safety enhancement, service recommendations and mobile entertainment. A fundamental issue that impacts the success of these applications is the security and privacy concerns raised regarding the mobile users. In that, a malicious user or service provider can track the locations of a user traveled so that other malicious act can be carried out more effectively against the user. Therefore, the challenge becomes how to authenticate mobile users while preserving their actual identity and location privacy. In this work, we propose a novel randomized or privacy-preserving authentication protocol based on homomorphic encryption. The protocol allows individual users to self generate any number of authenticated identities to achieve full anonymity in mobile environment. The proposed protocol prevents users being tracked by any single party including peer users, service providers, authentication servers, and other infrastructure. Meanwhile, our protocol also provides traceability in case of any dispute. We have conducted experimental study which demonstrates the efficiency of our protocol. Another advantage of the proposed protocol is lightweight computation and storage requirement, particularly suitable for any mobile devices with limited computation power and storage space

    Biphenyl-2,2′,4,4′-tetra­carb­oxy­lic acid monohydrate

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    In the title compound, C16H10O8·H2O, the dihedral angle between the two benzene rings is 71.63 (5)°. In the crystal structure, pairs of inversion-related mol­ecules are stacked [mean inter­planar spacing = 3.5195 (18) Å], and O—H⋯O and C—H⋯O hydrogen bonds create a three-dimensional network

    Osthole induces G2/M arrest and apoptosis in lung cancer A549 cells by modulating PI3K/Akt pathway

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    <p>Abstract</p> <p>Background</p> <p>To explore the effects of Osthole on the proliferation, cell cycle and apoptosis of human lung cancer A549 cells.</p> <p>Methods</p> <p>Human lung cancer A549 cells were treated with Osthole at different concentrations. Cell proliferation was measured using the MTT assay. Cell cycle was evaluated using DNA flow cytometry analysis. Induction of apoptosis was determined by flow cytometry and fluorescent microscopy. The expressions of Cyclin B1, p-Cdc2, Bcl-2, Bax, t-Akt and p-Akt were evaluated by Western blotting.</p> <p>Results</p> <p>Osthole inhibited the growth of human lung cancer A549 cells by inducing G2/M arrest and apoptosis. Western blotting demonstrated that Osthole down-regulated the expressions of Cyclin B1, p-Cdc2 and Bcl-2 and up-regulated the expressions of Bax in A549 cells. Inhibition of PI3K/Akt signaling pathway was also observed after treating A549 cells with Osthole.</p> <p>Conclusions</p> <p>Our findings suggest that Osthole may have a therapeutic application in the treatment of human lung cancer.</p
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