177 research outputs found

    Implementing BERT and fine-tuned RobertA to detect AI generated news by ChatGPT

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    The abundance of information on social media has increased the necessity of accurate real-time rumour detection. Manual techniques of identifying and verifying fake news generated by AI tools are impracticable and time-consuming given the enormous volume of information generated every day. This has sparked an increase in interest in creating automated systems to find fake news on the Internet. The studies in this research demonstrate that the BERT and RobertA models with fine-tuning had the best success in detecting AI generated news. With a score of 98%, tweaked RobertA in particular showed excellent precision. In conclusion, this study has shown that neural networks can be used to identify bogus news AI generation news created by ChatGPT. The RobertA and BERT models' excellent performance indicates that these models can play a critical role in the fight against misinformation

    A Fast and Provable Algorithm for Sparse Phase Retrieval

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    We study the sparse phase retrieval problem, which aims to recover a sparse signal from a limited number of phaseless measurements. Existing algorithms for sparse phase retrieval primarily rely on first-order methods with linear convergence rate. In this paper, we propose an efficient second-order algorithm based on Newton projection, which maintains the same per-iteration computational complexity as popular first-order methods. The proposed algorithm is theoretically guaranteed to converge to the ground truth (up to a global sign) at a quadratic convergence rate after at most O(log(x/xmin))O\big(\log (\Vert \mathbf{x}^{\natural} \, \Vert /x_{\min}^{\natural})\big) iterations, provided a sample complexity of O(s2logn)O(s^2\log n), where xRn\mathbf{x}^{\natural} \in \mathbb{R}^n represents an ss-sparse ground truth signal. Numerical experiments demonstrate that our algorithm not only outperforms state-of-the-art methods in terms of achieving a significantly faster convergence rate, but also excels in attaining a higher success rate for exact signal recovery from noise-free measurements and providing enhanced signal reconstruction in noisy scenarios

    Cosmological Fisher forecasts for next-generation spectroscopic surveys

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    Next-generation spectroscopic surveys such as the MegaMapper, MUltiplexed Survey Telescope (MUST), MaunaKea Spectroscopic Explorer (MSE), and Wide Spectroscopic Telescope (WST) are foreseen to increase the number of galaxy/quasar redshifts by an order of magnitude, with hundred millions of spectra that will be measured at z>2z>2. We perform a Fisher matrix analysis for these surveys on the baryonic acoustic oscillation (BAO), the redshift-space distortion (RSD) measurement, the non-Gaussianity amplitude fNLf_{\rm NL}, and the total neutrino mass MνM_\nu. For BAO and RSD parameters, these surveys may achieve precision at sub-percent level (<0.5 per cent), representing an improvement of factor 10 w.r.t. the latest database. For NG, these surveys may reach an accuracy of σ(fNL)1\sigma(f_{\rm NL})\sim 1. They can also put a tight constraint on MνM_\nu with σ(Mν)0.02eV\sigma(M_\nu) \sim 0.02\,\rm eV if we do joint analysis with Planck and even 0.01eV 0.01\,\rm eV if combined with other data. In addition, we introduce a general survey model, to derive the cosmic volume and number density of tracers, given instrumental facilities and survey strategy. Using our Fisher formalism, we can explore (continuously) a wide range of survey observational parameters, and propose different survey strategies that optimise the cosmological constraints. Fixing the fibre number and survey duration, we show that the best strategy for fNLf_{\rm NL} and MνM_\nu measurement is to observe large volumes, despite the noise increase. However, the strategy differs for the apparent magnitude limit. Finally, we prove that increasing the fibre number improves MνM_{\nu} measurement but not significantly fNLf_{\rm NL}.Comment: 15 pages, 9 figure

    Research on dedicated rail power supply system for electric cars

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    in order to improve the endurance capacity and driving safety of electric vehicles, a special track power supply system for electric cars on expressways is studied. The working principle of the main components of the system, such as sliding contact charging track and mechanical charging arm, is simulated and analyzed by using SolidWorks software. The results show that the charging function of the contact track can provide unlimited endurance for electric vehicles, and the guidance function of the track can also ensure the safety of highspeed driving

    WaveDM: Wavelet-Based Diffusion Models for Image Restoration

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    Latest diffusion-based methods for many image restoration tasks outperform traditional models, but they encounter the long-time inference problem. To tackle it, this paper proposes a Wavelet-Based Diffusion Model (WaveDM) with an Efficient Conditional Sampling (ECS) strategy. WaveDM learns the distribution of clean images in the wavelet domain conditioned on the wavelet spectrum of degraded images after wavelet transform, which is more time-saving in each step of sampling than modeling in the spatial domain. In addition, ECS follows the same procedure as the deterministic implicit sampling in the initial sampling period and then stops to predict clean images directly, which reduces the number of total sampling steps to around 5. Evaluations on four benchmark datasets including image raindrop removal, defocus deblurring, demoir\'eing, and denoising demonstrate that WaveDM achieves state-of-the-art performance with the efficiency that is comparable to traditional one-pass methods and over 100 times faster than existing image restoration methods using vanilla diffusion models

    Short Video Activism With and on Douyin: An Innovative Repertoire of Contention for Chinese Consumers

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    This article examines consumer video activism tactics in China and their impact on Chinese consumers and society. Drawing upon 56 semistructured interviews and a case study analysis of Chinese online consumer protest in 2018, we argue that short-video-activism tactics have become an innovative repertoire of contention for Chinese consumers and Douyin, the “sister app” of TikTok, has become a real-time updated database of this repertoire. Using Douyin as a case study, we argue that it plays three key roles in mediating Chinese consumer activism: a techno-cultural construct that affords highly heterogeneous users to present everyday experiences via short videos; a multisided market that profoundly affects the tactics consumers choose to amplify their voices; and a governing entity that both moderates content for its users and simultaneously is subject to government regulations

    Growth and nutrient dynamics of transplanted Quercus variabilis seedlings as influenced by pre-hardening and fall fertilization

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    Stored nutrient reserves are closely correlated with survival and growth of transplanted seedlings. Previous studies have proven that combining pre-hardening fertilization (PF) with fall fertilization (FF) built seedling nutrient reserves more effectively; however, their effect on transplanting performance is poorly documented. We investigated the independent and interacting effects of 2 levels of PF and 4 levels of FF on seedling growth, nutrient acquisition and accumulation during different growth phases 1 year after transplanting of Blume in a nursery. High PF benefited nutrient reserves and subsequent transplanted seedling growth and tissue nutrient storage at the end of the rapid growth and hardening phases. Fall fertilization with 36 mg N increased stem dry mass and tissue nutrient content at the end of the hardening phase. At the conclusion of establishment, PF and FF showed a significant interaction for N and K uptake from soil. At the end of the rapid growth and hardening phases, high PF consistently increased nutrient uptake. Enhanced N and K uptake occurred following application of 36 mg N of FF at the end of the hardening phase. Distinct roles for PF and FF on 3 phases of transplanted seedlings demonstrated the necessity to evaluate fertilization in terms of nutrient reserves and subsequent transplanting performance in consecutive phases. Combining 100 mg N seedling during pre-hardening with 36 mg N seedling during fall yielded ideal transplanting performance for seedlings.Quercus variabilis â1â1Quercus variabili

    Symmetry breaking induced insulating electronic state in Pb9_{9}Cu(PO4_4)6_6O

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    The recent experimental claim of room-temperature ambient-pressure superconductivity in a Cu-doped lead-apatite (LK-99) has ignited substantial research interest in both experimental and theoretical domains. Previous density functional theory (DFT) calculations with the inclusion of an on-site Hubbard interaction UU consistently predict the presence of flat bands crossing the Fermi level. This is in contrast to DFT plus dynamical mean field theory calculations, which reveal the Mott insulating behavior for the stoichiometric Pb9_{9}Cu(PO4_4)6_6O compound. Nevertheless, the existing calculations are all based on the P63/mP6_3/m structure, which is argued to be not the ground-state structure. Here, we revisit the electronic structure of Pb9_{9}Cu(PO4_4)6_6O with the energetically more favorable P3ˉP\bar{3} structure, fully taking into account electronic symmetry breaking. We examine all possible configurations for Cu substituting the Pb sites. Our results show that the doped Cu atoms exhibit a preference for substituting the Pb2 sites than the Pb1 sites. In both cases, the calculated substitutional formation energies are large, indicating the difficulty in incorporating Cu at the Pb sites. We find that most of structures with Cu at the Pb2 site tend to be insulating, while the structures with both two Cu atoms at the Pb1 sites (except one configuration) are predicted to be metallic by DFT+UU calculations. However, when accounting for the electronic symmetry breaking, some Cu-doped configurations previously predicted to be metallic (including the structure studied in previous DFT+UU calculations) become insulating. Our work highlights the importance of symmetry breaking in obtaining correct electronic state for Pb9_{9}Cu(PO4_4)6_6O, thereby reconciling previous DFT+UU and DFT+DMFT calculations.Comment: 19 pages, 9 figures (including Supplementary Material

    Study of the Bus Dynamic Coscheduling Optimization Method under Urban Rail Transit Line Emergency

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    As one of the most important urban commuter transportation modes, urban rail transit (URT) has been acting as a key solution for supporting mobility needs in high-density urban areas. However, in recent years, high frequency of unexpected events has caused serious service disruptions in URT system, greatly harming passenger safety and resulting in severe traffic delays. Therefore, there is an urgent need to study emergency evacuation problem in URT. In this paper, a method of bus dynamic coscheduling is proposed and two models are built based on different evacuation destinations including URT stations and surrounding bus parking spots. A dynamic coscheduling scheme for buses can be obtained by the models. In the model solution process, a new concept—the equivalent parking spot—is proposed to transform the nonlinear model into an integer linear programming (ILP) problem. A case study is conducted to verify the feasibility of models. Also, sensitivity analysis of two vital factors is carried out to analyze their effects on the total evacuation time. The results reveal that the designed capacity of buses has a negative influence on the total evacuation time, while an increase in the number of passengers has a positive effect. Finally, some significant optimizing strategies are proposed

    Void Lensing in Cubic Galileon Gravity

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    Weak lensing studies via cosmic voids are a promising probe of Modified Gravity (MG). Excess surface mass density (ESD) is widely used as a lensing statistic in weak lensing research. In this paper, we use the ray-tracing method to study the ESD around voids in simulations based on Cubic Galileon (CG) gravity. With the compilation of N-body simulation and ray-tracing method, changes in structure formation and deflection angle resulting from MG can both be considered, making the extraction of lensing signals more realistic. We find good agreements between the measurement and theoretical prediction of ESD for CG gravity. Meanwhile, the lensing signals are much less affected by the change of the deflection angle than the change of the structure formation, indicating a good approximation of regarding ESD (statistics) as the projection of 3D dark matter density field. Finally, we demonstrate that it is impossible to distinguish CG and General Relativity in our simulation, however, in the next-generation survey, thanks to the large survey area and the increased galaxy number density, detecting the differences between these two models is possible. The methodology employed in this paper that combines N-body simulation and ray-tracing method can be a robust way to measure the lensing signals from simulations based on the MGs, and especially on that which significantly modifies the deflection angle.Comment: 14 pages, 9 figure
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