81 research outputs found

    Modeling and simulation of equivalent second-order pendulum model of casting crane based on liquid slosh

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    Because the load of the foundry crane is the molten metal of high temperature liquid, the liquid in the load will produce different amplitude sloshing during the operation process, showing a complex solid-liquid coupling phenomenon. The conventional modeling method of treating the load as a solid can no longer meet the control requirements. In order to solve this problem, the equivalent second-order pendulum model of liquid sloshing is established in this paper. On this basis, the dynamic equation of casting bridge crane is derived by Lagrange method. Then a sliding mode variable structure controller is designed and simulated. The experimental results verify the dynamic characteristics and effectiveness of the nonlinear model, and realize the precise positioning of the trolley and the effective anti-swing of the load

    CD13 Inhibition Enhances Cytotoxic Effect of Chemotherapy Agents

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    Multidrug resistance (MDR) of hepatocellular carcinoma is a serious problem. Although CD13 is a biomarker in human liver cancer stem cells, the relationship between CD13 and MDR remains uncertain. This study uses liver cancer cell model to understand the role of CD13 in enhancing the cytotoxic effect of chemotherapy agents. Cytotoxic agents can induce CD13 expression. CD13 inhibitor, bestatin, enhances the antitumor effect of cytotoxic agents. Meanwhile, CD13-targeting siRNA and neutralizing antibody can enhance the cytotoxic effect of 5-fluorouracil (5FU). CD13 overexpression increases cell survival upon cytotoxic agents treatment, while the knockdown of CD13 causes hypersensitivity of cells to cytotoxic agents treatment. Mechanistically, the inhibition of CD13 leads to the increase of cellular reactive oxygen species (ROS). BC-02 is a novel mutual prodrug (hybrid drug) of bestatin and 5FU. Notably, BC-02 can inhibit cellular activity in both parental and drug-resistant cells, accompanied with significantly increased ROS level. Moreover, the survival time of Kunming mice bearing H22 cells under BC-02 treatment is comparable to the capecitabine treatment at maximum dosage. These data implicate a therapeutic method to reverse MDR by targeting CD13, and indicate that BC-02 is a potent antitumor compound

    A new paradigm for multiple description video coding

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    Multiple description coding (MDC) is a source coding technique that exploits path diversity to combat packet losses over error-prone channels. In this thesis, we proposed a novel drift-free multi-state MDC method. At the encoder side, the original video is compressed into multiple independently decodable H.263 streams, each with its own coding structure and prediction process, such that if one stream is lost, the other stream can still be used to produce video with acceptable quality. At the decoder side, each description is considered as a noisy observation of the original video. A minimum mean-square error (MMSE) based joint reconstruction algorithm is proposed to combine the descriptions. The experimental results show that the proposed algorithm has high coding efficiency, yet with strong error resilience

    MicroRNAs: Game Changers in the Regulation of α-Synuclein in Parkinson’s Disease

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    Parkinson’s disease (PD) is the second most common neurodegenerative disorder. Its neuropathological hallmarks include neuronal loss in the substantia nigra pars compacta (SNpc) and the presence of Lewy bodies containing aggregates of α-synuclein (α-syn). An imbalance between the rates of α-syn synthesis, aggregation, and clearance can result in abnormal α-syn levels and contribute to the pathogenesis of PD. MicroRNAs (miRNAs) are endogenous single-stranded noncoding RNAs (∼22 nucleotides) that have recently emerged as key posttranscriptional regulators of gene expression. In this review, we summarize the functions of miRNAs that directly target α-syn. We also review miRNAs that indirectly impact α-syn levels or toxicity through different pathways, including those involved in the clearance of α-syn and neuroinflammation

    Optimal mean-variance reinsurance with common shock dependence

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    We consider the optimal proportional reinsurance problem for an insurer with two dependent classes of insurance business, where the two claim number processes are correlated through a common shock component. Using the technique of stochastic linear–quadratic control theory and the Hamilton–Jacobi–Bellman equation, we derive the explicit expressions for the optimal reinsurance strategies and value function, and present the verification theorem within the framework of the viscosity solution. Furthermore, we extend the results in the linear–quadratic setting to the mean–variance problem, and obtain an efficient strategy and frontier. Some numerical examples are given to show the impact of model parameters on the efficient frontier. doi:10.1017/S144618111600016

    An Encoder-Embedded Video Denoising Filter Based On The Temporal LMMSE Estimator

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    Noise not only degrades the visual quality of video contents, but also significantly affects the coding efficiency. Based on the temporal linear minimum mean square error (LMMSE) estimator, an innovative denoising filter is proposed in this paper. The proposed filter only requires simple operations manipulating on the individual residue coefficients and can be seamlessly integrated into video encoders. Compared to traditional filter-encoder cascaded scheme, embedding the proposed filter into the video encoder can save a large amount of computation. The experimental results show that with the proposed filter embedded, both the noise suppression capability and the coding efficiency of the video encoder can be dramatically improved. Furthermore, as a purely temporal filter, it can well preserve the fine details of video contents and satisfactory visual quality can be achieved. 1

    On the security of multimedia encryption schemes based on multiple Huffman table (MHT)

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    This paper addresses the security issues of the multimedia encryption schemes based on multiple Huffman table (M-HT). A detailed analysis of known-plaintext attack is presented to show that the Huffman tables used for encryption should be carefully selected to avoid the weak keys problem. Further, we propose an efficient chosen-plaintext attack on the basic MHT method as well as the enhanced scheme inserting random bits. We also show that random rotation in partitioned bit stream cannot essentially improve the security

    Security Analysis of Multimedia Encryption Schemes Based on Multiple Huffman Table

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    This letter addresses the security issues of the multimedia encryption schemes using multiple Huffman table (MHT). A known-plaintext attack is presented to show that the MHTs used for encryption should be carefully selected to avoid the weak keys problem. We then propose chosen-plaintext attacks on the basic MHT algorithm as well as the enhanced scheme with random bit insertion. In addition, we suggest two empirical criteria for Huffman table selection, based on which we can simplify the stream cipher integrated scheme, while ensuring a high level of security

    Temporal Video Denoising Based on Multihypothesis Motion Compensation

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    Denoising module. is required by any practical video processing systems. Most existing denoising schemes are spatio-temporal filters which operate on data over three dimensions. However, to limit the number of inputs, these filters only utilize one reference frame and cannot fully exploit temporal correlation. In this paper, a recursive temporal denoising filter named multihypothesis motion compensated filter (MHMCF) is proposed. To fully exploit temporal correlation, MHMCF performs motion estimation in a number of reference frames to construct multiple hypotheses (temporal predictions) of the current pixel. These hypotheses are combined by weighted averaging to suppress noise and estimate the actual current pixel value. Based on the multihypothesis motion compensated residue model presented in this paper, we investigate the efficiency of MHMCF, and some numerical evaluations are revealed. Experimental results show that MHMCF demonstrates quite good denoising performance while the inputs are much fewer than spatio-temporal filters. Moreover, as a purely temporal filter, it can well preserve spatial details and achieve satisfactory visual quality

    Exact symbol error rate for variable length codes over binary symmetric channel

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    In this paper, we analyze the error recovery performance of variable length codes (VLCs) transmitted over binary symmetric channel (BSC). Simple expressions for the exact mean symbol error rate (MSER) and the exact variance of symbol error rate (VSER) for any crossover probability p, are presented. We also prove that the mean error propagation length (MEPL) derived for single bit inversion error case is a scaled value of MSER when p, tends to zero. Comparisons with simulations demonstrate the accuracy of the MSER and VSER expressions
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