Test selection is to select the test set with the least total cost or the least total number from the alternative test set on the premise of meeting the required testability indicators.The existing models and methods ...Test selection is to select the test set with the least total cost or the least total number from the alternative test set on the premise of meeting the required testability indicators.The existing models and methods are not suitable for system level test selection.The first problem is the lack of detailed data of the units’fault set and the test set,which makes it impossible to establish a traditional dependency matrix for the system level.The second problem is that the system level fault detection rate and the fault isolation rate(referred to as"two rates")are not enough to describe the fault diagnostic ability of the system level tests.An innovative dependency matrix(called combinatorial dependency matrix)composed of three submatrices is presented.The first problem is solved by simplifying the submatrix between the units’fault and the test,and the second problem is solved by establishing the system level fault detection rate,the fault isolation rate and the integrated fault detection rate(referred to as"three rates")based on the new matrix.The mathematical model of the system level test selection problem is constructed,and the binary genetic algorithm is applied to solve the problem,which achieves the goal of system level test selection.展开更多
Birefringence (polarization-related phase-shift), polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in opt...Birefringence (polarization-related phase-shift), polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers. This paper obtains a new Mueller matrix analysis, which can be used under conditions that all these three factors are existing and changing. According to our transmission model, the state of polarization (SOP) changes along an optical mierostructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results, which show the phenomena of SOP constringency, are in good agreement with previous theoretical analyses.展开更多
The paper demonstrates the possibility to enhance the damping of inter-area oscillations using Wide Area Measurement (WAM) based adaptive supervisory controller (ASC) which considers the wide-area signal transmission ...The paper demonstrates the possibility to enhance the damping of inter-area oscillations using Wide Area Measurement (WAM) based adaptive supervisory controller (ASC) which considers the wide-area signal transmission delays. The paper uses an LMI-based iterative nonlinear optimization algorithm to establish a method of designing state-feedback controllers for power systems with a time-varying delay. This method is based on the delay-dependent stabilization conditions obtained by the improved free weighting matrix (IFWM) approach. In the stabilization conditions, the upper bound of feedback signal’s transmission delays is taken into consideration. Combining theoriesof state feedback control and state observer, the ASC is designed and time-delay output feedback robust controller is realized for power system. The ASC uses the input information from Phase Measurement Units (PMUs) in the system and dispatches supplementary control signals to the available local controllers. The design of the ASC is explained in detail and its performance validated by time domain simulations on a New England test power system (NETPS).展开更多
In this paper, a lower bound of maximal dimensions of commutable matrix spaces (CMS) is given. It is found that the linear dependence of a group of one to one commutable matrices is related to whether some equations i...In this paper, a lower bound of maximal dimensions of commutable matrix spaces (CMS) is given. It is found that the linear dependence of a group of one to one commutable matrices is related to whether some equations in system can be eliminated. The corresponding relation is given. By introducing conceptions of eliminating set and eliminating index, we give an estimation of upper bound of maximal dimensions of CMS. For special cases n=5,6, the further estimation of maximal dimensions of CMS is presented.展开更多
Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmet...Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmetrical three-phase line on untransposed conditions is associated with Clarke’s matrix for error and frequency scan analyses in this paper. Error analyses are calculated for the eigenvalue diagonal elements obtained from Clarke’s matrix. The eigenvalue off-diagonal elements from the Clarke’s matrix application are compared to the correspondent exact eigenvalues. Based on the characteristic impedance and propagation function values, the frequency scan analyses show that there are great differences between the Clarke’s matrix results and the exact ones, considering frequency values from 10 kHz to 1 MHz. A correction procedure is applied obtaining two new transformation matrices. These matrices lead to good approximated results when compared to the exact ones. With the correction procedure applied to Clarke’s matrix, the relative values of the eigenvalue matrix off-diagonal element obtained from Clarke’s matrix are decreased while the frequency scan results are improved. The steps of correction procedure application are detailed, investigating the influence of each step on the obtained two new phase-mode transformation matrices.展开更多
这份报纸讨论延期依赖者的问题为有州的延期的不明确的单个系统的柔韧的 H 控制。把途径基于线性矩阵不平等(LMI ) ,我们设计一个州的反馈控制器,它保证为所有可被考虑的无常,结果的靠近环的系统是常规的,推动与 H 免费、稳定的标...这份报纸讨论延期依赖者的问题为有州的延期的不明确的单个系统的柔韧的 H 控制。把途径基于线性矩阵不平等(LMI ) ,我们设计一个州的反馈控制器,它保证为所有可被考虑的无常,结果的靠近环的系统是常规的,推动与 H 免费、稳定的标准界限限制。所有获得的结果是延期依赖者并且由不包含系统矩阵的分解的严格的 LMI 提出。数字例子证明建议方法不比存在的保守。展开更多
This paper studies the problem of stability for continuous-time systems with differentiable time-varying delays.By using the information of delay derivative,improved asymptotic stability conditions for time-delay syst...This paper studies the problem of stability for continuous-time systems with differentiable time-varying delays.By using the information of delay derivative,improved asymptotic stability conditions for time-delay systems are presented.Unlike the previous methods,the upper bound of the delay derivative is taken into consideration even if this upper bound is larger than or equal to 1.It is proved that the obtained results are less conservative than the existing ones.Meanwhile,the computational complexity of the presented stability criteria is reduced greatly since fewer decision variables are involved.Numerical examples are given to illustrate the effectiveness and less conservatism of the obtained stability conditions.展开更多
基金supported by the National Natural Science Foundation of China(51605482)the Equipment Pre-research Project(41403020101).
文摘Test selection is to select the test set with the least total cost or the least total number from the alternative test set on the premise of meeting the required testability indicators.The existing models and methods are not suitable for system level test selection.The first problem is the lack of detailed data of the units’fault set and the test set,which makes it impossible to establish a traditional dependency matrix for the system level.The second problem is that the system level fault detection rate and the fault isolation rate(referred to as"two rates")are not enough to describe the fault diagnostic ability of the system level tests.An innovative dependency matrix(called combinatorial dependency matrix)composed of three submatrices is presented.The first problem is solved by simplifying the submatrix between the units’fault and the test,and the second problem is solved by establishing the system level fault detection rate,the fault isolation rate and the integrated fault detection rate(referred to as"three rates")based on the new matrix.The mathematical model of the system level test selection problem is constructed,and the binary genetic algorithm is applied to solve the problem,which achieves the goal of system level test selection.
基金supported by the National Natural Science Foundation of China(Grants Nos.60877057 and 60907027)
文摘Birefringence (polarization-related phase-shift), polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers. This paper obtains a new Mueller matrix analysis, which can be used under conditions that all these three factors are existing and changing. According to our transmission model, the state of polarization (SOP) changes along an optical mierostructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results, which show the phenomena of SOP constringency, are in good agreement with previous theoretical analyses.
文摘The paper demonstrates the possibility to enhance the damping of inter-area oscillations using Wide Area Measurement (WAM) based adaptive supervisory controller (ASC) which considers the wide-area signal transmission delays. The paper uses an LMI-based iterative nonlinear optimization algorithm to establish a method of designing state-feedback controllers for power systems with a time-varying delay. This method is based on the delay-dependent stabilization conditions obtained by the improved free weighting matrix (IFWM) approach. In the stabilization conditions, the upper bound of feedback signal’s transmission delays is taken into consideration. Combining theoriesof state feedback control and state observer, the ASC is designed and time-delay output feedback robust controller is realized for power system. The ASC uses the input information from Phase Measurement Units (PMUs) in the system and dispatches supplementary control signals to the available local controllers. The design of the ASC is explained in detail and its performance validated by time domain simulations on a New England test power system (NETPS).
基金Supported by the Youth Mainstay Teacher Foundation of HunanProvince Educational Committee
文摘In this paper, a lower bound of maximal dimensions of commutable matrix spaces (CMS) is given. It is found that the linear dependence of a group of one to one commutable matrices is related to whether some equations in system can be eliminated. The corresponding relation is given. By introducing conceptions of eliminating set and eliminating index, we give an estimation of upper bound of maximal dimensions of CMS. For special cases n=5,6, the further estimation of maximal dimensions of CMS is presented.
文摘Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmetrical three-phase line on untransposed conditions is associated with Clarke’s matrix for error and frequency scan analyses in this paper. Error analyses are calculated for the eigenvalue diagonal elements obtained from Clarke’s matrix. The eigenvalue off-diagonal elements from the Clarke’s matrix application are compared to the correspondent exact eigenvalues. Based on the characteristic impedance and propagation function values, the frequency scan analyses show that there are great differences between the Clarke’s matrix results and the exact ones, considering frequency values from 10 kHz to 1 MHz. A correction procedure is applied obtaining two new transformation matrices. These matrices lead to good approximated results when compared to the exact ones. With the correction procedure applied to Clarke’s matrix, the relative values of the eigenvalue matrix off-diagonal element obtained from Clarke’s matrix are decreased while the frequency scan results are improved. The steps of correction procedure application are detailed, investigating the influence of each step on the obtained two new phase-mode transformation matrices.
文摘这份报纸讨论延期依赖者的问题为有州的延期的不明确的单个系统的柔韧的 H 控制。把途径基于线性矩阵不平等(LMI ) ,我们设计一个州的反馈控制器,它保证为所有可被考虑的无常,结果的靠近环的系统是常规的,推动与 H 免费、稳定的标准界限限制。所有获得的结果是延期依赖者并且由不包含系统矩阵的分解的严格的 LMI 提出。数字例子证明建议方法不比存在的保守。
基金Program for New Century Excellent Talents in University(NCET-04-0283)the Funds for Creative Research Groups of China(60521003)+3 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT0421)the State Key Program of National Natural Science Foundation of China(60534010)National Natural Science Foundatiou of China(60674021)the Funds of Ph.D.Program of Ministry of Education,China(20060145019)
文摘This paper studies the problem of stability for continuous-time systems with differentiable time-varying delays.By using the information of delay derivative,improved asymptotic stability conditions for time-delay systems are presented.Unlike the previous methods,the upper bound of the delay derivative is taken into consideration even if this upper bound is larger than or equal to 1.It is proved that the obtained results are less conservative than the existing ones.Meanwhile,the computational complexity of the presented stability criteria is reduced greatly since fewer decision variables are involved.Numerical examples are given to illustrate the effectiveness and less conservatism of the obtained stability conditions.
基金Supported by National High Technology Research and Development Program of China (863 Program) (2006AA04Z182), National Natu- ral Science Foundation of China (60736021), and National Creative Research Groups Science Foundation of China (60721062)