In this paper,a differential scheme is proposed for reconfigurable intelligent surface(RIS)assisted spatial modulation,which is referred to as RISDSM,to eliminate the need for channel state information(CSI)at the rece...In this paper,a differential scheme is proposed for reconfigurable intelligent surface(RIS)assisted spatial modulation,which is referred to as RISDSM,to eliminate the need for channel state information(CSI)at the receiver.The proposed scheme is an improvement over the current differential modulation scheme used in RIS-based systems,as it avoids the high-order matrix calculation and improves the spectral efficiency.A mathematical framework is developed to determine the theoretical average bit error probability(ABEP)of the system using RIS-DSM.The detection complexity of the proposed RIS-DSM scheme is extremely low through the simplification.Finally,simulations results demonstrate that the proposed RIS-DSM scheme can deliver satisfactory error performance even in low signal-to-noise ratio environments.展开更多
In this paper, based on the idea of El-Mistikawy and Werle[1] we construct a difference scheme for a singularly perturbed self-adjoint ordinary differential equation in conservation form. We prove that it is a uniform...In this paper, based on the idea of El-Mistikawy and Werle[1] we construct a difference scheme for a singularly perturbed self-adjoint ordinary differential equation in conservation form. We prove that it is a uniformly convergent second order scheme.展开更多
The second-order backward differential formula(BDF2)and the scalar auxiliary variable(SAV)approach are applied to con‐struct the linearly energy stable numerical scheme with the variable time steps for the epitaxial ...The second-order backward differential formula(BDF2)and the scalar auxiliary variable(SAV)approach are applied to con‐struct the linearly energy stable numerical scheme with the variable time steps for the epitaxial thin film growth models.Under the stepratio condition 0<τ_(n)/τ_(n-1)<4.864,the modified energy dissipation law is proven at the discrete levels with regardless of time step size.Nu‐merical experiments are presented to demonstrate the accuracy and efficiency of the proposed numerical scheme.展开更多
As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, t...As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, the most scientific and effective method is chain-system differential analysis and the most short-cutting method is the method of net annual value, to select the NA V maximum scheme.展开更多
The limitation of fault currents from converter based distributed generators(CBDGs)in hybrid AC/DC islanded microgrids poses a significant challenge for microgrid protection.This paper presents a novel interharmonic c...The limitation of fault currents from converter based distributed generators(CBDGs)in hybrid AC/DC islanded microgrids poses a significant challenge for microgrid protection.This paper presents a novel interharmonic current differential protection scheme for the AC side of hybrid AC/DC islanded microgrids supplied by CBDGs.During faults,the proposed scheme exploits the varying interharmonic components of the currents at both terminals of the faulted line,arise due to variations in the droop-based no-load frequency limits of the interlinking converters(ICs)and the CBDGs.By leveraging these variations,the scheme effectively detects and isolates internal faults within the AC sub-grid,enhancing system reliability.The effectiveness of the suggested scheme is assessed using an enhanced IEEE33-bus hybrid AC/DC microgrid modelled in PSCAD/EMTDC,demonstrating its ability to reliably detect and isolate faults under various operating conditions.Additionally,the scheme is further evaluated using a real-time hardware-in-the-loop experimental setup implemented on an RTDS platform,validating its practical applicability.The simulation and experimental results validate that the presented protection scheme accurately discriminates between normal and faulty conditions across various fault locations,types,and resistance values.This discrimination is achieved without requiring high-bandwidth communication,overcoming a key limitation of existing protection schemes and improving feasibility in real-world deployments.展开更多
In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see add...In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see additive extrapolation method before. This new method has a great advantage over additive extrapolation method because it keeps group property. If this method is used to construct higher order schemes from lower symplectic schemes, the higher order ones are also symplectic. First we introduce the concept of adjoint methods and some of their properties. We show that there is a self-adjoint scheme corresponding to every method. With this self-adjoint scheme of lower order, we can construct higher order schemes by multiplicative extrapolation method, which can be used to construct even much higher order schemes. Obviously this constructing process can be continued to get methods of arbitrary even order.展开更多
In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drop...In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drops the head of the contending burst only if the overlapping region of the two bursts is less than the whole contending burst size, otherwise drops the whole contending burst. In order to have a better support of differentiated service, a new burst assembly policy, namely, Priority-based proportional mixed burst assembly, is proposed. Simulation results show that the proposed scheme performs very well in terms of performance metrics such as the times of contention and packet loss probability.展开更多
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, t...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.展开更多
基金supported by National Natural Science Foundation of China(No.61801106).
文摘In this paper,a differential scheme is proposed for reconfigurable intelligent surface(RIS)assisted spatial modulation,which is referred to as RISDSM,to eliminate the need for channel state information(CSI)at the receiver.The proposed scheme is an improvement over the current differential modulation scheme used in RIS-based systems,as it avoids the high-order matrix calculation and improves the spectral efficiency.A mathematical framework is developed to determine the theoretical average bit error probability(ABEP)of the system using RIS-DSM.The detection complexity of the proposed RIS-DSM scheme is extremely low through the simplification.Finally,simulations results demonstrate that the proposed RIS-DSM scheme can deliver satisfactory error performance even in low signal-to-noise ratio environments.
文摘In this paper, based on the idea of El-Mistikawy and Werle[1] we construct a difference scheme for a singularly perturbed self-adjoint ordinary differential equation in conservation form. We prove that it is a uniformly convergent second order scheme.
文摘The second-order backward differential formula(BDF2)and the scalar auxiliary variable(SAV)approach are applied to con‐struct the linearly energy stable numerical scheme with the variable time steps for the epitaxial thin film growth models.Under the stepratio condition 0<τ_(n)/τ_(n-1)<4.864,the modified energy dissipation law is proven at the discrete levels with regardless of time step size.Nu‐merical experiments are presented to demonstrate the accuracy and efficiency of the proposed numerical scheme.
文摘As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, the most scientific and effective method is chain-system differential analysis and the most short-cutting method is the method of net annual value, to select the NA V maximum scheme.
基金supported by the ASPIRE Virtual Research Institute Program,Advanced Technology Research Council(No.VRI20-07),UAE.
文摘The limitation of fault currents from converter based distributed generators(CBDGs)in hybrid AC/DC islanded microgrids poses a significant challenge for microgrid protection.This paper presents a novel interharmonic current differential protection scheme for the AC side of hybrid AC/DC islanded microgrids supplied by CBDGs.During faults,the proposed scheme exploits the varying interharmonic components of the currents at both terminals of the faulted line,arise due to variations in the droop-based no-load frequency limits of the interlinking converters(ICs)and the CBDGs.By leveraging these variations,the scheme effectively detects and isolates internal faults within the AC sub-grid,enhancing system reliability.The effectiveness of the suggested scheme is assessed using an enhanced IEEE33-bus hybrid AC/DC microgrid modelled in PSCAD/EMTDC,demonstrating its ability to reliably detect and isolate faults under various operating conditions.Additionally,the scheme is further evaluated using a real-time hardware-in-the-loop experimental setup implemented on an RTDS platform,validating its practical applicability.The simulation and experimental results validate that the presented protection scheme accurately discriminates between normal and faulty conditions across various fault locations,types,and resistance values.This discrimination is achieved without requiring high-bandwidth communication,overcoming a key limitation of existing protection schemes and improving feasibility in real-world deployments.
文摘In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see additive extrapolation method before. This new method has a great advantage over additive extrapolation method because it keeps group property. If this method is used to construct higher order schemes from lower symplectic schemes, the higher order ones are also symplectic. First we introduce the concept of adjoint methods and some of their properties. We show that there is a self-adjoint scheme corresponding to every method. With this self-adjoint scheme of lower order, we can construct higher order schemes by multiplicative extrapolation method, which can be used to construct even much higher order schemes. Obviously this constructing process can be continued to get methods of arbitrary even order.
基金This work was partially supported by the National Natural Science Foundation of China under Grant No. 69990540.
文摘In this letter, we analyze the drawback of tail-dropping contention resolution in optical burst switched networks. Once contention occurs, we adopt modified head-dropping policy to resolve contention. This policy drops the head of the contending burst only if the overlapping region of the two bursts is less than the whole contending burst size, otherwise drops the whole contending burst. In order to have a better support of differentiated service, a new burst assembly policy, namely, Priority-based proportional mixed burst assembly, is proposed. Simulation results show that the proposed scheme performs very well in terms of performance metrics such as the times of contention and packet loss probability.
基金the National Natural Science Foundation of China(NSFC),under Grant No.71871151.The authors thank the anonymous referees and editors for their valuable comments that significantly contributed towards improving the quality of the paper.
文摘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.
