To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunication...To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunications industry characteristics,and then classifies these indicators into the following factors:operation scale,profitability,solvency and asset management ability by factor analysis.This paper also gives the priorities of these four factors by regression analysis,of which the operation scale is the most important factor.The research results point out a clear method for the telecom operatorsto increase their EVA in order to meet the performance appraisal from State-owned Assets Supervision and Administration Commission of the State Council.展开更多
The existence of solutions for second order three-point boundary value problems with nonlinear growth at resonance is studied by using Mawhin continuation theorem. The result shows that theorem 1 and 2 at least have o...The existence of solutions for second order three-point boundary value problems with nonlinear growth at resonance is studied by using Mawhin continuation theorem. The result shows that theorem 1 and 2 at least have one solution in c1[0,1]展开更多
In this paper,we give a fixed point theorem for multi-valued composite increasing operators,in partially ordered spaces,which generalizes the results of [1]-[3] and [5]- [8].
In this paper,we give a fixed point theorem for multi-valued composite increasing operators, which generalizes the theorem of the paper [1] under not only multi-valued mappings but also single-valued mappings. And we...In this paper,we give a fixed point theorem for multi-valued composite increasing operators, which generalizes the theorem of the paper [1] under not only multi-valued mappings but also single-valued mappings. And we generalizes the corresponding results of [2]-[5].展开更多
Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound so...Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.展开更多
Hydraulic fracture is one of the key methods in well stimulation to increase production of oil and gas.Crack Opening Displacement(COD) is of great importance in this method since it is in direct relation with permeabi...Hydraulic fracture is one of the key methods in well stimulation to increase production of oil and gas.Crack Opening Displacement(COD) is of great importance in this method since it is in direct relation with permeability and production rate.In this paper COD is measured by a distinct element model which has been validated by an exact solution.A comprehensive study has been performed on confining pressure effect on COD which is neglected in the analytical solution.Numerical results showed that confining pressure considerably affects COD.A multi-parameter regression(considering effect of confining pressure,rock mass properties and fluid pressure) was performed on numerical results which resulted in an equation.The proposed equation considers the effect of confining pressure and its results are in good agreement with numerical results.展开更多
文摘To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunications industry characteristics,and then classifies these indicators into the following factors:operation scale,profitability,solvency and asset management ability by factor analysis.This paper also gives the priorities of these four factors by regression analysis,of which the operation scale is the most important factor.The research results point out a clear method for the telecom operatorsto increase their EVA in order to meet the performance appraisal from State-owned Assets Supervision and Administration Commission of the State Council.
文摘The existence of solutions for second order three-point boundary value problems with nonlinear growth at resonance is studied by using Mawhin continuation theorem. The result shows that theorem 1 and 2 at least have one solution in c1[0,1]
文摘In this paper,we give a fixed point theorem for multi-valued composite increasing operators,in partially ordered spaces,which generalizes the results of [1]-[3] and [5]- [8].
文摘In this paper,we give a fixed point theorem for multi-valued composite increasing operators, which generalizes the theorem of the paper [1] under not only multi-valued mappings but also single-valued mappings. And we generalizes the corresponding results of [2]-[5].
文摘Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.
文摘Hydraulic fracture is one of the key methods in well stimulation to increase production of oil and gas.Crack Opening Displacement(COD) is of great importance in this method since it is in direct relation with permeability and production rate.In this paper COD is measured by a distinct element model which has been validated by an exact solution.A comprehensive study has been performed on confining pressure effect on COD which is neglected in the analytical solution.Numerical results showed that confining pressure considerably affects COD.A multi-parameter regression(considering effect of confining pressure,rock mass properties and fluid pressure) was performed on numerical results which resulted in an equation.The proposed equation considers the effect of confining pressure and its results are in good agreement with numerical results.
