366 research outputs found

    Prediction of diesel engine particulate emission during transient cycles

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    A computer model has been developed to predict diesel engine particulate emission during transients in speed and torque. The computer model consists of a quasi-steady-state engine combustion model, a dynamic engine model, and a dynamic turbocharger model. The model predictions were compared to experimentally measured particulate emissions. Particulate matter was measured under steady-state conditions, over an EPA transcient cycle, and for discrete segments of various transient cycles;The computer model accurately predicts engine air flow rate, turbocharger speed, and instantaneous engine equivalence ratio. The fuel consumption given by the model is within 3% of the experimental measurement over the transient cycle. The brake specific particulate emission during the transient cycle is also accurately predicted by the model. The predicted particulate emission is within 5% of the averaged experimental data over the EPA transient cycle

    Analysis of Maximum Threshold and Quantum Security for Fault-Tolerant Encoding and Decoding Scheme Base on Steane Code

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    Steane code is one of the most widely studied quantum error-correction codes, which is a natural choice for fault-tolerant quantum computation (FTQC). However, the original Steane code is not fault-tolerant because the CNOT gates in an encoded block may cause error propagation. In this paper, we first propose a fault-tolerant encoding and decoding scheme, which analyzes all possible errors caused by each quantum gate in an error-correction period. In this scheme, we combine the results of measuring redundant qubits with those of syndrome measurements to identify specific errors for different types of errors. But due to the error propagation, there may be cases where different errors produce the same measurement results. Therefore, we introduce the "flag qubits" scheme (providing its usage conditions) to reduce error interference as much as possible, and we consider the errors caused by the introduced quantum gates, realizing the truly fault-tolerant Steane code. Afterwards, we provide the fault-tolerant scheme of the universal quantum gate set, including fault-tolerant preparation and verification of ancillary states. This is the first time that fault tolerance has been considered for every process of FTQC. Finally, We propose an algorithm for a more accurate estimation of thresholds and optimal error-correction period selection. Our simulation results based on this entire scheme demonstrate the effectiveness of this algorithm, satisfying the threshold theorem and the currently widely recognized threshold. We analyze the relationship among the maximum threshold, concatenated levels, and quantum logical depth, showing that quantum operations play a crucial role in increasing the threshold. Furthermore, we analyze the computational theoretical limits of quantum computers from the perspectives of attack and active defense based on our FTQC scheme, thereby assessing the security of a system

    Consistency of the generalized MLE of a joint distribution function with multivariate interval-censored data

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    AbstractWong and Yu [Generalized MLE of a joint distribution function with multivariate interval-censored data, J. Multivariate Anal. 69 (1999) 155–166] discussed generalized maximum likelihood estimation of the joint distribution function of a multivariate random vector whose coordinates are subject to interval censoring. They established uniform consistency of the generalized MLE (GMLE) of the distribution function under the assumption that the random vector is independent of the censoring vector and that both of the vector distributions are discrete. We relax these assumptions and establish consistency results of the GMLE under a multivariate mixed case interval censorship model. van der Vaart and Wellner [Preservation theorems for Glivenko–Cantelli and uniform Glivenko–Cantelli class, in: E. Gine, D.M. Mason, J.A. Wellner (Eds.), High Dimensional Probability, vol. II, Birkhäuser, Boston, 2000, pp. 115–133] and Yu [Consistency of the generalized MLE with multivariate mixed case interval-censored data, Ph.D Dissertation, Binghamton University, 2000] independently proved strong consistency of the GMLE in the L1(μ)-topology, where μ is a measure derived from the joint distribution of the censoring variables. We establish strong consistency of the GMLE in the topologies of weak convergence and pointwise convergence, and eventually uniform convergence under appropriate distributional assumptions and regularity conditions

    ASYMPTOTIC DISTRIBUTIONS OF THE BUCKLEY-JAMES ESTIMATOR UNDER NONSTANDARD CONDITIONS

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    Abstract: The Buckley-James estimator (BJE) is the most appropriate extension of the least squares estimator (LSE) to the right-censored linear regression model

    Towards Top-Down Reasoning: An Explainable Multi-Agent Approach for Visual Question Answering

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    Recently, Vision Language Models (VLMs) have gained significant attention, exhibiting notable advancements across various tasks by leveraging extensive image-text paired data. However, prevailing VLMs often treat Visual Question Answering (VQA) as perception tasks, employing black-box models that overlook explicit modeling of relationships between different questions within the same visual scene. Moreover, the existing VQA methods that rely on Knowledge Bases (KBs) might frequently encounter biases from limited data and face challenges in relevant information indexing. Attempt to overcome these limitations, this paper introduces an explainable multi-agent collaboration framework by tapping into knowledge embedded in Large Language Models (LLMs) trained on extensive corpora. Inspired by human cognition, our framework uncovers latent information within the given question by employing three agents, i.e., Seeker, Responder, and Integrator, to perform a top-down reasoning process. The Seeker agent generates relevant issues related to the original question. The Responder agent, based on VLM, handles simple VQA tasks and provides candidate answers. The Integrator agent combines information from the Seeker agent and the Responder agent to produce the final VQA answer. Through the above collaboration mechanism, our framework explicitly constructs a multi-view knowledge base for a specific image scene, reasoning answers in a top-down processing manner. We extensively evaluate our method on diverse VQA datasets and VLMs, demonstrating its broad applicability and interpretability with comprehensive experimental results.Comment: 16 pages, 9 figure

    Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells

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    The evaluation of the toxicity of magnetic nanoparticles (MNPs) has attracted much attention in recent years. The current study aimed to investigate the cytotoxic effects of Fe3O4, oleic acid-coated Fe3O4 (OA-Fe3O4), and carbon-coated Fe (C-Fe) nanoparticles on human hepatoma BEL-7402 cells and the mechanisms. WST-1 assay demonstrated that the cytotoxicity of three types of MNPs was in a dose-dependent manner. G1 (Fe3O4 and OA-Fe3O4) phase and G2 (C-Fe) phase cell arrests and apoptosis induced by MNPs were detected by flow cytometry analysis. The increase in apoptosis was accompanied with the Bax over-expression, mitochondrial membrane potential decrease, and the release of cytochrome C from mitochondria into cytosol. Moreover, apoptosis was further confirmed by morphological and biochemical hallmarks, such as swollen mitochondria with lysing cristae and caspase-3 activation. Our results revealed that certain concentrations of the three types of MNPs affect BEL-7402 cells viability via cell arrest and inducing apoptosis, and the MNPs-induced apoptosis is mediated through the mitochondrial-dependent pathway. The influence potency of MNPs observed in all experiments would be: C-Fe > Fe3O4 > OA-Fe3O4

    LHPP promotes the intracellular reactive oxygen species accumulation and sensitivity of gastric cancer to cisplatin via JNK and p38 MAPK pathways

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    Background. Cisplatin is the first-line chemotherapy drug for the treatment of gastric cancer (GC) patients. However, GC patients who are resistant to cisplatin often do not benefit from it. Therefore, finding a key molecule that affects cisplatin sensitivity is expected to enhance the efficacy of cisplatin in GC treatment. Methods. The human GC cell lines SGC-7901 and BGC-823 were used. The protein chip array was used to screen the cisplatin-resistance genes from the complete response and non-complete response GC patients’ tissues, then, the differential gene expression analysis, GO function annotation analysis, and KEGG pathway enrichment analysis were performed. The GC tissue chip in the GEO database was analyzed to screen the target gene. Flow cytometry, Hoechst 33342 staining assay, Western Blot, MTT, tumor sphere formation, cell cycle, and apoptosis assays were performed to explore the effect of Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP) on the apoptosis, stemness, and reactive oxygen species (ROS) accumulation of cisplatin-resistant GC cells treated with cisplatin. In vivo, the cisplatin-resistant GC cell lines transfected with pcDNA-LHPP or si-LHPP were injected subcutaneously into mice to construct GC subcutaneous xenograft GC models. Results. Based on protein chip array and bioinformatics analysis, it was found that LHPP is the core molecule in the cisplatin resistance regulatory network in GC, and its expression is down-regulated in GC cisplatin-resistant tissues and cells. In vitro and in vivo experimental results show that the up-regulated expression of LHPP is closely related to the increase in sensitivity of GC to cisplatin. Mechanically, we found that overexpression of LHPP may inhibit the activation of the JNK and p38 MAPK pathways, promote cisplatininduced ROS accumulation, suppress stemness, and enhance the sensitivity of GC to cisplatin. Conclusions. Up-regulation of LHPP may inhibit the activation of the JNK and p38 MAPK pathways, attenuate stemness, and enhance the accumulation of intracellular ROS, thereby promoting cisplatin-mediated GC cell apoptosis and enhancing cisplatin sensitivity

    DNA barcoding and comparative RNA-Seq analysis provide new insights into leaf formation using a novel resource of high-yielding Epimedium koreanum

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    Epimedium koreanum Nakai, a well-known traditional Chinese medicinal herb, has been widely used to treat osteoporosis and sexual dysfunction for thousands of years. However, due to the decreasing population of East Asian natural resources, yearly output of Epimedium crude herb has been in low supply year by year. In this study, an unusual variety of E. koreanum was discovered in Dunhua, Jilin Province, the northernmost area where this variety was found containing 6 individuals, with three branches that had 27 leaflets, which is much more than the typical leaflet number of 9. Firstly, the novel E. koreanum varety was identified using DNA barcodes. Then, 1171 differentially expressed genes (DEGs) were discovered through parallel RNA-seq analysis between the newly discovered variety and wild type (WT) E. koreanum plant. Furthermore, the results of bioinformatics investigation revealed that 914 positively and 619 negatively correlated genes associated with the number of leaflets. Additionally, based on RNA-Seq and qRT-PCR analysis, two homologous hub TCP genes, which were commonly implicated in plant leaf development, and shown to be up regulated and down regulated in the discovered newly variety, respectively. Thus, our study discovered a novel wild resource for leaf yield rewarding medicinal Epimedium plant breeding, provided insights into the relationship between plant compound leaf formation and gene expression of TCPs transcription factors and other gene candidates, providing bases for creating high yield cultivated Epimedium variety by using further molecular selection and breeding techniques in the future
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