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Predicting impact strength of perforated targets using artificial neural networks trained on FEM-generated datasets

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Defence Technology（防务技术） 2024年第2期32卷 32-44页

作者： Nikita Kazarinov Aleksandr Khvorov Saint Petersburg State University Saint Petersburg 199034Russia Higher school of economics Saint Petersburg 190121Russia

The paper considers application of artificial neural networks(ANNs)for fast numerical evaluation of a residual impactor velocity for a family of perforated PMMA(Polymethylmethacrylate)*** ANN models were trained using sets of numerical results on impact of PMMA plates obtained via dynamic FEM coupled with incubation time fracture *** developed approach makes it possible to evaluate the impact strength of a particular target configuration without complicated FEM calculations which require considerable computational ***,it is shown that the ANN models are able to predict results for the configurations which cannot be processed using the developed FEM routine due to numerical instabilities and errors:the trained neural network uses information from successful computations to obtain results for the problematic cases.A simple static problem of a perforated plate deformation is discussed prior to the impact problem and preferable ANN architectures are presented for both *** insight into the perforation pattern optimization using a genetic algorithm coupled with the ANN is also made and optimized perforation patterns which theoretically enhance the target impact strength are constructed.

关键词： Machine learning Impact Dynamic fracture FEM Mesh distortion Optimization

Collateral Monetary Policy,Regional Financial Development,and Nonfinancial Firms'Shadow Banking Activities

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China & World Economy 2024年第5期32卷 166-196页

作者： Chao Yuan Hai Jiang Jiawen Ren Nikos Kapitsinis school of Finance Guangdong University of Finance and EconomicsChina Department of Finance School of EconomicsJinan UniversityChina University of Copenhagen Denmark

The disparity in credit access between large firms and small and medium-sized enterprises contributes to the prevalence of shadow banking activities,where large,nonfinancial firms with high credit ratings have become new financial *** activities vary geographically and are afected significantly by collateral monetary *** paper examines the effect of collateral monetary policy,its reform,and regional financial development characteristics on large firms'shadow banking activities,with a focus on the medium-term lending facility(MLF),the primary collateral monetary policy instrument in *** results indicate that the MLF encouraged large firms'shadow banking ***,the MLF reform in 2018 mitigated this effect by broadening the range of acceptable *** financial development,such as a higher number of bank branches around firms,facilitated large firms'shadow banking activities and amplified the MLF's stimulating *** contrast,regional advancements in digital finance and market development limited both shadow banking activities and MLF's impact.

关键词： collateral monetary policy financial geography medium-term lending facilities shadow banking

Sliced Average Variance Estimation for Tensor Data

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 630-655页

作者： Chuan-quan LI Pei-wen XIAO Chao YING Xiao-hui LIU school of Statistics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and economics Jiangxi University of Finance and EconomicsNanchang 330013China Biostatistics and Medical Informatics University of Wisconsin MadisonMadison 53726USA

Tensor data have been widely used in many fields,e.g.,modern biomedical imaging,chemometrics,and economics,but often suffer from some common issues as in high dimensional *** to find their low-dimensional latent structure has been of great interest for *** this end,we develop two efficient tensor sufficient dimension reduction methods based on the sliced average variance estimation(SAVE)to estimate the corresponding dimension reduction *** first one,entitled tensor sliced average variance estimation(TSAVE),works well when the response is discrete or takes finite values,but is not■consistent for continuous response;the second one,named bias-correction tensor sliced average variance estimation(CTSAVE),is a de-biased version of the TSAVE *** asymptotic properties of both methods are derived under mild *** and real data examples are also provided to show the superiority of the efficiency of the developed methods.

关键词： tensor data sliced average variance estimation sufficient dimension reduction central subspace

High-dimensional robust inference for censored linear models

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Science China Mathematics 2024年第4期67卷 891-918页

作者： Jiayu Huang Yuanshan Wu school of Mathematics and Statistics Wuhan UniversityWuhan 430072China school of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073China

Due to the direct statistical interpretation,censored linear regression offers a valuable complement to the Cox proportional hazards regression in survival *** propose a rank-based high-dimensional inference for censored linear regression without imposing any moment condition on the model *** develop a theory of the high-dimensional U-statistic,circumvent challenges stemming from the non-smoothness of the loss function,and establish the convergence rate of the regularized estimator and the asymptotic normality of the resulting de-biased estimator as well as the consistency of the asymptotic variance *** censoring can be viewed as a way of trimming,it strengthens the robustness of the rank-based high-dimensional inference,particularly for the heavy-tailed model error or the outlier in the presence of the *** evaluate the finite-sample performance of the proposed method via extensive simulation studies and demonstrate its utility by applying it to a subcohort study from The Cancer Genome Atlas(TCGA).

关键词： censoring mechanism heavy-tailed distribution non-smooth loss function outlier rank regression

Value-added Tax and Leverage:Evidence from China's Value-added Tax Rate Reform

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China & World Economy 2024年第2期32卷 200-234页

作者： Hongsheng Fang Lexin Zhao Xiufen Liu school of economics and Institute for Fiscal Big-Data and PolicyZhejiang UniversityChina school of economics Zhejiang UniversityChina school of Business Hangzhou City UniversityChina

This paper uses China's value-added tax(VAT)rate reform as a quasi-natural experiment to identify the impacts of VAT rate shocks on corporate financial *** results indicate that the reform reduced corporate total leverage *** was a decrease in short-term leverage,but long-term leverage showed no significant *** results remained robust across a series of robustness *** analysis shows that increasing profitability and improving cash flows acted as intermediary channels for the reform's impact on *** reform also contributed to the mitigation of the asset–liability mismatch problem and the reduction of debt risk,while having no apparent impact on corporate ***,enterprises with more elastic demand and those with lower intermediate input ratios were affected most by the deleveraging effect of the VAT rate *** study suggests how the VAT rate cut shaped corporate capital *** thus helps to explain the economic consequences of VAT rate shocks.

关键词： asset-liability ratio capital structure tax reduction VAT rate reform

Central environmental protection inspection and carbon emission reduction: A tripartite evolutionary game model from the perspective of carbon neutrality

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Petroleum Science 2024年第3期21卷 2139-2153页

作者： Zhen-Hua Zhang Dan Ling Qin-Xin Yang Yan-Chao Feng Jing Xiu school of economics Lanzhou UniversityLanzhou 730000GansuChina Institute of Green Finance Lanzhou UniversityLanzhou 730000GansuChina school of Management Lanzhou UniversityLanzhou 730000GansuChina school of Business Zhengzhou UniversityZhengzhou 450001HenanChina Institute of economics Jilin Academy of Social SciencesChangchun130033JilinChina

Since the carbon neutrality target was proposed,many countries have been facing severe challenges to carbon emission reduction *** study is conducted using a tripartite evolutionary game model to explore the impact of the central environmental protection inspection(CEPI)on driving carbon emission reduction,and to study what factors influence the strategic choices of each party and how they interact with each *** research results suggest that local governments and manufacturing enterprises would choose strategies that are beneficial to carbon reduction when CEPI *** the initial willingness of all parties increases 20%,50%—80%,the time spent for the whole system to achieve stability decreases from 100%,60%—30%.The evolutionary result of“thorough inspection,regulation implementation,low-carbon management”is the best strategy for the tripartite evolutionary ***,the smaller the cost and the larger the benefit,the greater the likelihood of the three-party game stability strategy *** study has important guiding significance for other developing countries to promote carbon emission reduction by environmental policy.

关键词： Central environmental protection inspection Local government Manufacturing enterprise Tripartite evolutionary game Carbon emission reduction

Asymptotic normality of error density estimator in stationary and explosive autoregressive models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 140-158页

作者： WU Shi-peng YANG Wen-zhi GAO Min HU Shu-he school of Mathematical Sciences&school of Big Data and Statistics Anhui UniversityHefei 230601China school of Statistics Shanxi University of Finance and EconomicsTaiyuan030006China

In this paper,we consider the limit distribution of the error density function estima-tor in the rst-order autoregressive models with negatively associated and positively associated random *** mild regularity assumptions,some asymptotic normality results of the residual density estimator are obtained when the autoregressive models are stationary process and explosive *** order to illustrate these results,some simulations such as con dence intervals and mean integrated square errors are provided in this *** shows that the residual density estimator can replace the density\estimator"which contains errors.

关键词： explosive autoregressive models residual density estimator asymptotic distribution association sequence

Factor Price Distortion,Technological Innovation,and High-Quality Economic Development

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Frontiers of economics in China-Selected Publications from Chinese Universities 2024年第1期19卷 91-105页

作者： WANG Xiaoyun school of Accounting Dongbei University of Finance and EconomicsDalian 116025China school of Accounting Dalian University of Finance and EconomicsDalian 116622China

The entropy method is used to measure the high-quality economic development levels of 30 provinces(autonomous regions,municipalities)in China from 2011 to 2020,and the impacts of factor price distortion,technological innovation,and their interaction terms on high-quality economic development are analyzed based on Tobit *** results show that highquality economic development of 30 provinces(autonomous regions,municipalities)in China is on the rise;factor price distortion has an inhibitory effect on high-quality economic development,while technological innovation has a promoting effect on high-quality economic development,and both of them have a lag effect;technological innovation level can help alleviate the negative impact of factor price distortion on high-quality economic development;and sub-regional research shows that the inhibitory effect of factor price distortion on highquality economic development in the east is significantly higher than that in the central and western regions,but the positive effect of technological innovation and the interaction terms between the two on high-quality economic development is significantly lower than that in the central and western ***,it is proposed to optimize top-level design for the two-wheel drive for high-quality economic development,strengthen the primary role of enterprises in innovation to promote high-quality economic development,and optimize the market-oriented allocation of factors to improve the efficiency of resource allocation.

关键词： factor price distortion technological innovation high-quality economic development entropymethod

A new evolutional model for institutional field knowledge flow network

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Journal of Data and Information Science 2024年第1期9卷 101-123页

作者： Jinzhong Guo Kai Wang Xueqin Liao Xiaoling Liu school of Information Management Xinjiang University of Finance and EconomicsUrumqiChina

Purpose:This paper aims to address the limitations in existing research on the evolution of knowledge flow networks by proposing a meso-level institutional field knowledge flow network evolution model(IKM).The purpose is to simulate the construction process of a knowledge flow network using knowledge organizations as units and to investigate its effectiveness in replicating institutional field knowledge flow ***/Methodology/Approach:The IKM model enhances the preferential attachment and growth observed in scale-free BA networks,while incorporating three adjustment parameters to simulate the selection of connection targets and the types of nodes involved in the network evolution process Using the PageRank algorithm to calculate the significance of nodes within the knowledge flow *** compare its performance,the BA and DMS models are also employed for simulating the *** coefficient analysis is conducted on the simulated networks generated by the IKM,BA and DMS models,as well as on the actual ***:The research findings demonstrate that the IKM model outperforms the BA and DMS models in replicating the institutional field knowledge flow *** provides comprehensive insights into the evolution mechanism of knowledge flow networks in the scientific research *** model also exhibits potential applicability to other knowledge networks that involve knowledge organizations as node *** Limitations:This study has some ***,it primarily focuses on the evolution of knowledge flow networks within the field of physics,neglecting other ***,the analysis is based on a specific set of data,which may limit the generalizability of the *** research could address these limitations by exploring knowledge flow networks in diverse fields and utilizing broader *** Implications:The proposed IKM model offers practical implications for the construction and analysis of knowledge

关键词： Knowledge flow networks Evolutionary mechanism BA model Knowledge units