We propose a boundary value correction method for the Brezzi-Douglas-Marini mixed finite element discretization of the Darcy flow with non-homogeneous Neumann boundary condition on 2D curved domains.The discretization...We propose a boundary value correction method for the Brezzi-Douglas-Marini mixed finite element discretization of the Darcy flow with non-homogeneous Neumann boundary condition on 2D curved domains.The discretization is defined on a body-fitted triangular mesh,i.e.the boundary nodes of the mesh lie on the curved physical boundary.However,the boundary edges of the triangular mesh,which are straight,may not coincide with the curved physical boundary.A boundary value correction technique is then designed to transform the Neumann boundary condition from the physical boundary to the boundary of the triangular mesh.One advantage of the boundary value correction method is that it avoids using curved mesh elements and thus reduces the complexity of implementation.We prove that the proposed method reaches optimal convergence for arbitrary order discretizations.Supporting numerical results are presented.展开更多
Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic...Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic seismic records in the process of calibration of the horizon.Through the analysis of the process and properties of the production of the RG line,in the processing of seismic data,it is indicated that the position of the synthetic data of seismic records is not located at the beginning of the RG line.Rather,it must be at the time point of the seismic profile at the elevation of a datum position of the static value of less than the datum plane.Both the RG line and the elevation static correction value line can easily be seen by computerizing the calculated value of the elevation static correction of the datum plane relating to the seismic section and plotting it on the seismic section.To achieve a good calibration with the synthetic seismogram,it is possible to set the starting point of the synthetic seismogram on the elevation static correction value line that is situated at the place of the Common Mid-Point(CMP).In the current paper,a systematic overview of methods and safety procedures for establishing the seismic interpretation work area and horizon calibration in seismic interpretation has been reviewed,which will form an effective guide towards seismic interpretation under the complicated surface conditions in the Bai Cheng west region.展开更多
By applying methods of investment appraisal, this paper offers a financial approach for determining the optimal level of segment-specific marketing activities and market development under the conditions of imperfect m...By applying methods of investment appraisal, this paper offers a financial approach for determining the optimal level of segment-specific marketing activities and market development under the conditions of imperfect markets and uncertainty. Within the scope of marketing planning and controlling, the model is suited to optimizing an enterprise＇s market activities and taking interdependencies between market segments, production, and investments into account. Applying duality theory of linear programming allows for identifying the income determinants and deriving formulas for a correct valuation by using （corrected） net present values （NPVs）. Under certain conditions, they can also be used to easily evaluate and financially interpret the effects of parameter changes. The author uses sensitivity analysis to support these findings and to obtain more information on the effects of these determinants.展开更多
The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless ...The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.12171244.
文摘We propose a boundary value correction method for the Brezzi-Douglas-Marini mixed finite element discretization of the Darcy flow with non-homogeneous Neumann boundary condition on 2D curved domains.The discretization is defined on a body-fitted triangular mesh,i.e.the boundary nodes of the mesh lie on the curved physical boundary.However,the boundary edges of the triangular mesh,which are straight,may not coincide with the curved physical boundary.A boundary value correction technique is then designed to transform the Neumann boundary condition from the physical boundary to the boundary of the triangular mesh.One advantage of the boundary value correction method is that it avoids using curved mesh elements and thus reduces the complexity of implementation.We prove that the proposed method reaches optimal convergence for arbitrary order discretizations.Supporting numerical results are presented.
文摘Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic seismic records in the process of calibration of the horizon.Through the analysis of the process and properties of the production of the RG line,in the processing of seismic data,it is indicated that the position of the synthetic data of seismic records is not located at the beginning of the RG line.Rather,it must be at the time point of the seismic profile at the elevation of a datum position of the static value of less than the datum plane.Both the RG line and the elevation static correction value line can easily be seen by computerizing the calculated value of the elevation static correction of the datum plane relating to the seismic section and plotting it on the seismic section.To achieve a good calibration with the synthetic seismogram,it is possible to set the starting point of the synthetic seismogram on the elevation static correction value line that is situated at the place of the Common Mid-Point(CMP).In the current paper,a systematic overview of methods and safety procedures for establishing the seismic interpretation work area and horizon calibration in seismic interpretation has been reviewed,which will form an effective guide towards seismic interpretation under the complicated surface conditions in the Bai Cheng west region.
文摘By applying methods of investment appraisal, this paper offers a financial approach for determining the optimal level of segment-specific marketing activities and market development under the conditions of imperfect markets and uncertainty. Within the scope of marketing planning and controlling, the model is suited to optimizing an enterprise＇s market activities and taking interdependencies between market segments, production, and investments into account. Applying duality theory of linear programming allows for identifying the income determinants and deriving formulas for a correct valuation by using （corrected） net present values （NPVs）. Under certain conditions, they can also be used to easily evaluate and financially interpret the effects of parameter changes. The author uses sensitivity analysis to support these findings and to obtain more information on the effects of these determinants.
文摘The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.
