The large-scale online supermarket is a newly emerging online retailing mode which brings great convenience to people.Online supermarkets are characterized by having large amounts of daily orders with potentially mult...The large-scale online supermarket is a newly emerging online retailing mode which brings great convenience to people.Online supermarkets are characterized by having large amounts of daily orders with potentially multiple items,diverse delivery times,and a high order-split rate.Multiple shipments for one order caused by order splitting result in high cost and disturbance and a large number of discarded consumable packages at online retailers and customers,causing severe damage to the environment.Accordingly,research on split-order consolidation fulfilment is critical for the advancement of the practice and theory in the context of highly complex online retailing.This paper first analyzes the characteristics and the challenges associated with the split-order consolidation problem that online supermarket is confronting and summarizes the new operational process of split-order consolidation fulfilment.Then,a time–space network optimization model is built,and its corresponding solution algorithm is presented to solve the questions of where and when to consolidate the split orders.Finally,the computation results of the numerical experiments are provided to verify the effectiveness of the algorithm,and a sensitivity analysis of the relevant parameters is performed.This work highlights the effect of order consolidation processes and fulfilment methods on the order fulfilment decision-making for online supermarkets.The purpose of this article is to help pave the way for more effective online supermarket management and order implementation.展开更多
Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attracti...Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attractive design criterion for selecting fractional factorial split-plot design. In this paper, we are interested in the theoretical construction methods of the optimal fractional factorial split-plot designs under the general minimum lower order confounding criterion. We present the theoretical construction methods of optimal fractional factorial split-plot designs under general minimum lower order confounding criterion under several conditions.展开更多
A novel Time-Interleaved Analog-to-Digital Converter (TIADC) digital background calibration for the mismatches of offsets, gain errors, and timing skews based on split-ADC is proposed. Firstly, the split-ADC channels ...A novel Time-Interleaved Analog-to-Digital Converter (TIADC) digital background calibration for the mismatches of offsets, gain errors, and timing skews based on split-ADC is proposed. Firstly, the split-ADC channels in present TIADC architecture are designed to convert input signal at two different channel sampling rates so that redundant channel to facilitate pair permutation is avoided. Secondly, a high-order compensation scheme for correction of timing skew error is employed for effective calibration to preserve high-resolution when input frequency is high. Numerical simulation performed by MATLAB for a 14-bit TIADC based on 7 split-ADC channels shows that Signal-to-Noise and Distortion Ratio (SNDR) and Spurious Free Dynamic Range (SFDR) of the TIADC achieve 86.2 dBc and 106 dBc respectively after calibration with normalized input frequency near Nyquist frequency.展开更多
As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order elec...As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order electromagnetic wave equation. However, the PML boundary condition is difficult to apply in GPR Finite Element Time Domain (FETD) simulation based on the second order electromagnetic wave equation. This paper developed a non-split perfectly matched layer (NPML) boundary condition for GPR FETD simulation based on the second order electromagnetic wave equation. Taking two-dimensional TM wave equation as an example, the second order frequency domain equation of GPR was derived according to the definition of complex extending coordinate transformation. Then it transformed into time domain by means of auxiliary differential equation method, and its FETD equation is derived based on Galerkin method. On this basis, a GPR FETD forward program based on NPML boundary condition is developed. The merits of NPML boundary condition are certified by compared with wave field snapshots, signal and reflection errors of homogeneous medium model with split and non-split PML boundary conditions. The comparison demonstrated that the NPML algorithm can reduce memory occupation and improve calculation efficiency. Furthermore, numerical simulation of a complex model verifies the good absorption effects of the NPML boundary condition in complex structures.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.72071078 and 72101230).
文摘The large-scale online supermarket is a newly emerging online retailing mode which brings great convenience to people.Online supermarkets are characterized by having large amounts of daily orders with potentially multiple items,diverse delivery times,and a high order-split rate.Multiple shipments for one order caused by order splitting result in high cost and disturbance and a large number of discarded consumable packages at online retailers and customers,causing severe damage to the environment.Accordingly,research on split-order consolidation fulfilment is critical for the advancement of the practice and theory in the context of highly complex online retailing.This paper first analyzes the characteristics and the challenges associated with the split-order consolidation problem that online supermarket is confronting and summarizes the new operational process of split-order consolidation fulfilment.Then,a time–space network optimization model is built,and its corresponding solution algorithm is presented to solve the questions of where and when to consolidate the split orders.Finally,the computation results of the numerical experiments are provided to verify the effectiveness of the algorithm,and a sensitivity analysis of the relevant parameters is performed.This work highlights the effect of order consolidation processes and fulfilment methods on the order fulfilment decision-making for online supermarkets.The purpose of this article is to help pave the way for more effective online supermarket management and order implementation.
基金supported by the Natural Science Foundation of Shandong Province(Grant Nos.ZR2020MA032,ZR2022MA029)the National Natural Science Foundation of China(Grant No.72171133)the high-quality course for postgraduate education in Shandong Province《Intermediate Econometrics(Graded Teaching)》(SDYKC21137).
文摘Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attractive design criterion for selecting fractional factorial split-plot design. In this paper, we are interested in the theoretical construction methods of the optimal fractional factorial split-plot designs under the general minimum lower order confounding criterion. We present the theoretical construction methods of optimal fractional factorial split-plot designs under general minimum lower order confounding criterion under several conditions.
基金Supported by the National Natural Science Foundation of China (No. 61076026)
文摘A novel Time-Interleaved Analog-to-Digital Converter (TIADC) digital background calibration for the mismatches of offsets, gain errors, and timing skews based on split-ADC is proposed. Firstly, the split-ADC channels in present TIADC architecture are designed to convert input signal at two different channel sampling rates so that redundant channel to facilitate pair permutation is avoided. Secondly, a high-order compensation scheme for correction of timing skew error is employed for effective calibration to preserve high-resolution when input frequency is high. Numerical simulation performed by MATLAB for a 14-bit TIADC based on 7 split-ADC channels shows that Signal-to-Noise and Distortion Ratio (SNDR) and Spurious Free Dynamic Range (SFDR) of the TIADC achieve 86.2 dBc and 106 dBc respectively after calibration with normalized input frequency near Nyquist frequency.
文摘As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order electromagnetic wave equation. However, the PML boundary condition is difficult to apply in GPR Finite Element Time Domain (FETD) simulation based on the second order electromagnetic wave equation. This paper developed a non-split perfectly matched layer (NPML) boundary condition for GPR FETD simulation based on the second order electromagnetic wave equation. Taking two-dimensional TM wave equation as an example, the second order frequency domain equation of GPR was derived according to the definition of complex extending coordinate transformation. Then it transformed into time domain by means of auxiliary differential equation method, and its FETD equation is derived based on Galerkin method. On this basis, a GPR FETD forward program based on NPML boundary condition is developed. The merits of NPML boundary condition are certified by compared with wave field snapshots, signal and reflection errors of homogeneous medium model with split and non-split PML boundary conditions. The comparison demonstrated that the NPML algorithm can reduce memory occupation and improve calculation efficiency. Furthermore, numerical simulation of a complex model verifies the good absorption effects of the NPML boundary condition in complex structures.
