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The low Mach number limit of non-isentropic magnetohydrodynamic equations with large temperature variations in bounded domains

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Science China Mathematics 2024年第4期67卷 787-818页

作者： Min Liang Yaobin Ou school of Mathematics Renmin University of ChinaBeijing 100872China

This paper verifies the low Mach number limit of the non-isentropic compressible magnetohydrodynamic(MHD)equations with or without the magnetic diffusion in a three-dimensional bounded domain when the temperature variation is large but *** uniform estimates of strong solutions are established in a short time interval independent of the Mach number,provided that the slip boundary condition for the velocity and the Neumann boundary condition for the temperature are imposed and the initial data is well-prepared.

关键词： low Mach number limit non-isentropic compressible magnetohydrodynamic equations large temperature variations bounded domains

A Weighted Flow related to a Trudinger-Moser Functional on Closed Riemann Surface

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数学学报（英文版） 2024年第9期40卷 2244-2262页

作者： Peng Xiu YU school of Mathematics Renmin University of ChinaBeijing 100872P.R.China

In this paper,with(∑,g)being a closed Riemann surface,we analyze the possible concen-tration behavior of a heat flow related to the Trudinger-Moser *** obtain a long time existence for the *** along some sequence of times tk →+∞,we can deduce the convergence of the flow in H2(∑).Furthermore,the limit function is a critical point of the Trudinger-Moser functional under certain constraint.

关键词： 58J05 58J32 58J35 global convergence heat flow Trudinger-Moser inequality

Data-Driven Learning Control Algorithms for Unachievable Tracking Problems

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 205-218页

作者： Zeyi Zhang Hao Jiang Dong Shen Samer S.Saab the school of Mathematics Renmin University of ChinaBeijing 100872China IEEE the school of Engineering Lebanese American UniversityByblos 2038Lebanon

For unachievable tracking problems, where the system output cannot precisely track a given reference, achieving the best possible approximation for the reference trajectory becomes the objective. This study aims to investigate solutions using the Ptype learning control scheme. Initially, we demonstrate the necessity of gradient information for achieving the best ***, we propose an input-output-driven learning gain design to handle the imprecise gradients of a class of uncertain systems. However, it is discovered that the desired performance may not be attainable when faced with incomplete *** address this issue, an extended iterative learning control scheme is introduced. In this scheme, the tracking errors are modified through output data sampling, which incorporates lowmemory footprints and offers flexibility in learning gain *** input sequence is shown to converge towards the desired input, resulting in an output that is closest to the given reference in the least square sense. Numerical simulations are provided to validate the theoretical findings.

关键词： Data-driven algorithms incomplete information iterative learning control gradient information unachievable problems

Total Factor Productivity with Chinese Characteristics

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Social Sciences in China 2024年第1期45卷 54-70页

作者： Fan Xin Liu Wei school of Economics Renmin University of China

Although total factor productivity(TFP)is a common concept in mainstream Western economics,its origins are actually embedded in Marx's understanding of improving labor *** an important element of labor productivity under socialized production conditions,TFP is further reflected in the category of"socially necessary labor time"in two distinct ***-examining TFP from the perspective of Marxist political economy and incorporating it into the theoretical system of political economy of socialism with Chinese characteristics vividly illustrates the essence of"adhering to original principles,assimilating foreign concepts,and embracing a forward-looking vision"within political economy of socialism with Chinese *** practice,it is necessary to start with Marx's theory of productive labor and delineate the sectors involved in productive labor so that TFP and its fluctuations can be measured in a more relevant *** the context of the new era and the new journey,as the key to achieving high-quality economic development in China,efforts are needed to increase *** requires balancing economic factors such as the long term and short term,supply and demand,and gross quantity and structure,and promoting transformative changes in the quality,efficiency,and dynamism of economic development.

关键词： total factor productivity(TFP) technological progress technological effciency high-quality development

Omni-Channel Retailing and Firm Performance from a Customer Lifetime Value Perspective

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China Economist 2024年第3期19卷 89-103页

作者： Liu Xiangdong Mi Zhuang He Mingqin business school Renmin University of ChinaBeijing

In the digital era,retailers are keen to find out whether omni-channel retailing helps improve long-term firm *** this paper,we employ machine learning techniques on a large consumption data set in order to measure customer lifetime value(CLV)as the basis for determining long-term firm performance,and we provide an empirical analysis of the relationship between omni-channel retailing and *** results suggest that omni-channel retailing may effectively enhance *** analysis reveals that this process is influenced by heterogeneous consumer requirements and that significant differences exist in the extent to which the omni-channel transition may influence CLV depending on consumer preferences for diversity of commodities,sensitivity to the cost of contract performance,and sensitivity to warehousing ***,retailers should provide consumers with a complete portfolio of goods and services based on target consumers’heterogeneous requirements in order to increase omni-channel efficiency.

关键词： Omni-channel retailing customer lifetime value machine learning heterogeneous consumer requirements

A Theory of Digital Economy Development:An Examination of the Practice of Chinese Platforms

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Social Sciences in China 2024年第1期45卷 36-53页

作者： Huang Yanghua school of Applied Economics Renmin University of China

Grasping the development trends and patterns of the digital economy and promoting the integrated development of the digital and the real economy is a strategic choice for China's construction of new competitive *** on case studies of the growth of e-commerce,this paper develops five microeconomic propositions about the following issues:the microeconomic features of data factor that differ from traditional production factors;optimal decision-making for digital enterprises;“data+platform”architecture,data transaction governance,and digital infrastructure *** apply these theoretical propositions to enterprise innovative practices in different application scenarios such as driverless vehicles and manufacturing *** paper provides a systematic and consistent theoretical framework for analyzing platform business model innovation and accurately identifying issues of institutional construction that promote the integrated development of the digital and the real economy.

关键词： digital economy data factor data transactions data governance system real economy

Restricting Riesz-Logarithmic-Gagliardo-Lipschitz Potentials

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Acta Mathematica Sinica,English Series 2024年

作者： Xinting HU Liguang LIU school of Mathematics Renmin University of China

For s ∈ [0, 1], b ∈ R and p ∈ [1, ∞), let ■(Rn) be the logarithmic-Gagliardo-Lipschitz space, which arises as a limiting interpolation space and coincides to the classical Besov space when b = 0 and s ∈(0, 1). In this paper, the authors study restricting principles of the Riesz potential space Iα(■(Rn)) into certain Radon-Campanato space.

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A Heat Flow with Nonzero Potential for a Critical Trudinger-Moser Functional

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Acta Mathematicae Applicatae Sinica 2024年

作者： Peng-xiu YU school of Mathematics Renmin University of China

Let Ω?■2be a smooth bounded domain and H01(Ω) be the standard Sobolev space consisting of functions which vanish on?Ωand whose gradient is in L2(Ω).In this paper,we investigate critical points of the Trudinger-Mo...

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The Sequential Pricing of Ride-Hailing System with Rental Service in the Context of Fleet Electrification

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 77-105页

作者： Yaoyao Ku Peng Wu Qiang Ren Yiqing Wang business school Sichuan UniversityChengdu610065China

Surging demand and reduced capacity in the ride-hailing industry have prompted numerous ride-hailing platforms to build their own car-rental services catering to drivers who do not possess private vehicles. However, the trade-off between the ride-hailing service and the car-rental service is an important issue that is still unclear in theory. Moreover, ride-hailing platforms are transitioning towards all-electric fleets in the context of Carbon Neutrality goals and government regulations. This paper considers a ride-hailing system comprising a monopolist ride-hailing platform, an electric vehicle (EV) rental firm, and a gasoline vehicle (GV) rental firm. Furthermore, we build a stylized model to study the sequential pricing of the system. The equilibrium outcomes show the significant impact of the ride-hailing platform’s decision to continue or withdraw offering EV rental services on EV and GV drivers’ net earnings, rental prices, and wages. The ride-hailing platform providing EV rental services increases EV drivers’ net earnings but decreases the GV driver wages and rental prices. However, the EV rental service offered by the ride-hailing platform does not necessarily lead to an increased total profit for the system. The improved profitability of the system by the ride-hailing platform providing EV rental services is contingent upon lower rider prices and higher fuel costs. The ride-hailing platform’s EV rental services provision also effectively fosters the ride-hailing fleet’s electrification. Furthermore, as the number of riders increases, the ride-hailing platform should reduce the commission rate for EV drivers to maintain competitiveness and profitability.

关键词： Ride-hailing system car rental fleet electrification sequential pricing differential wage scheme