This paper proposes the use of the flexible tolerance method(FTM) modified with adaptive Nelder–Mead parameters and barrier to solve constrained optimization problems. The problems used to analyze the performance of ...This paper proposes the use of the flexible tolerance method(FTM) modified with adaptive Nelder–Mead parameters and barrier to solve constrained optimization problems. The problems used to analyze the performance of the methods were taken from G-Suite functions, and the methods with the best performance were applied in mass integration problems. Four methods were proposed:(1) flexible tolerance method(FTM) using adaptive parameters(FTMA),(2) flexible tolerance method with scaling(FTMS) and with adaptive parameters(FTMAS),(3) FTMS including the barrier modification(MFTMS) and(4) MFTMS hybridized with PSO(MFTMS-PSO). The success rates of these methods were 100%(MFTMS), 85%(MFTMS-PSO), 40%(FTMAS) and 30%(FTMA).Numerical experiments indicated that the MFTMS could efficiently and reliably improve the accuracy of global optima. In mass integration, the method was able, from current process situation, to reach the optimum process configuration that includes integration issues, which was not possible using FTM in its standard formulation. The hybridization of FTMS with PSO(without barrier), FTMS-PSO, was also able to solve mass integration problems efficiently.展开更多
In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is a...In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is affected by more than one mining panel, traditional PIM parameter inversion model is difficult to ensure the reliability of the results due to the complexity of rock movement. With crossover,mutation and selection operators, GA can perform a global optimization search and has high computation efficiency. Compared with the pattern search algorithm, the fitness function can avoid falling into local minima traps. GA reduces the risk of local minima traps which improves the accuracy and reliability with the mutation mechanism. Application at Xuehu colliery shows that GA can be used to inverse the PIM parameters for multi-panel surface movement observation, and reliable results can be obtained. The research provides a new way for back-analysis of PIM parameters for mining subsidence under complex conditions.展开更多
In this paper,an integrated guidance and control approach is presented to improve the performance of the missile interception.The approach includes damping augmented system with attitude rate feedback to decrease the ...In this paper,an integrated guidance and control approach is presented to improve the performance of the missile interception.The approach includes damping augmented system with attitude rate feedback to decrease the oscillation during the homing phase for missiles with low damping.In addition,physical constraints,which can affect the performance of the missile interception,such as acceleration limit,seeker’s look angle,and look angle rate constraints are considered.The integrated guidance and control problem is formulated as a convex quadratic optimization problem with equality and inequality constraints,and the solution is obtained by a primal–dual interior point method.The performance of the proposed method is verified through several numerical examples.展开更多
Current machining studies have reported effects of prevalent and common factors,while ultra⁃high finish requires holistic approach to identify all factors and investigate their effects on machining of hard to machine ...Current machining studies have reported effects of prevalent and common factors,while ultra⁃high finish requires holistic approach to identify all factors and investigate their effects on machining of hard to machine materials.In this work,a less investigated yet important factor,roughness of the uncut surface,was studied,and its effects on the individual response,i.e.,surface finish of the machined part,were found to be significant.AISI 316,which is mainly applied in strategic areas,was selected and three effective turning factors,cutting speed(A),feed rate(B),and roughness of the uncut surface(C)on three output responses including surface roughness of the machined surface(Ra),microhardness(HV),and material removal rate(MRR),were reported.Further,single response optimization of the individual output response and multi⁃response optimization of all the three responses were carried out.Taguchi L9 orthogonal array based signal⁃to⁃noise(S/N)ratio method was used for individual response optimization,and grey relational analysis(GRA)was employed for multi⁃response optimization.Effects of the process factors on the output responses were evaluated through inclusive statistical analyses.The individual response optimization revealed that there was a considerable effect of roughness of the uncut surface on the machining performance.Results of the GRA illustrated that the speed during the cutting process and the feed rate had substantial trace on the surface integrity(indicated by Ra and HV)and production rate(indicated by MRR),while roughness of the uncut surface did not have a significant effect.展开更多
Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of ...Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of MOC, in the context of lEGS's optimal scheduling. Specifically, the proposed method enables flexible temporal step sizes without sacrificing accuracy, significantly reducing non-convergence due to numerical oscillations. The effectiveness of the proposed method is validated through case studies in different simulation settings.展开更多
A PID parameters tuning and optimization method for a turbine engine based on the simplex search method was proposed. Taking time delay of combustion and actuator into account, a simulation model of a PID control syst...A PID parameters tuning and optimization method for a turbine engine based on the simplex search method was proposed. Taking time delay of combustion and actuator into account, a simulation model of a PID control system for a turbine engine was developed. A performance index based on the integral of absolute error （IAE） was given as an objective function of optimization. In order to avoid the sensitivity that resulted from the initial values of the simplex search method, the traditional Ziegler-Nichols method was used to tune PID parameters to obtain the initial values at first, then the simplex search method was applied to optimize PID parameters for the turbine engine. Simulation results indicate that the simplex search method is a reasonable and effective method for PID controller parameters tuning and optimization.展开更多
A strategy is proposed based on the stochastic averaging method for quasi non- integrable Hamiltonian systems and the stochastic dynamical programming principle.The pro- posed strategy can be used to design nonlinear ...A strategy is proposed based on the stochastic averaging method for quasi non- integrable Hamiltonian systems and the stochastic dynamical programming principle.The pro- posed strategy can be used to design nonlinear stochastic optimal control to minimize the response of quasi non-integrable Hamiltonian systems subject to Gaussian white noise excitation.By using the stochastic averaging method for quasi non-integrable Hamiltonian systems the equations of motion of a controlled quasi non-integrable Hamiltonian system is reduced to a one-dimensional av- eraged It stochastic differential equation.By using the stochastic dynamical programming princi- ple the dynamical programming equation for minimizing the response of the system is formulated. The optimal control law is derived from the dynamical programming equation and the bounded control constraints.The response of optimally controlled systems is predicted through solving the FPK equation associated with It stochastic differential equation.An example is worked out in detail to illustrate the application of the control strategy proposed.展开更多
Traditional topology optimization methods often introduce weak artificial material to mimic voids to avoid the singularity of the global stiffness matrix and carry out topology optimization with a fixed finite element...Traditional topology optimization methods often introduce weak artificial material to mimic voids to avoid the singularity of the global stiffness matrix and carry out topology optimization with a fixed finite element(FE)mesh.This treatment,however,may not only increase the computational cost for structural analysis but also lead to unfavorable numerical instabilities,especially when large deformations and dynamic/buckling behaviors are involved.In the present work,a new meshless moving morphable component-based method(ML-MMC),which structural analysis is carried out only on the solid region occupied by components,is proposed.In this approach,the coupling of discrete components is achieved through the adaptively constructed influence domain of the meshless shape function.Therefore,the singularity problem of the stiffness matrix can be naturally avoided without introducing weak artificial material.Compared with traditional methods,the number of degrees of freedoms(DOFs)can be reduced substantially under this treatment.The effectiveness of the proposed approach is also illustrated by some representative examples.展开更多
The penalty function method of continuum shape optimization and its sensitivity analysis technique are presented. A relatively simple integrated shape optimization system is developed and used to optimize the design o...The penalty function method of continuum shape optimization and its sensitivity analysis technique are presented. A relatively simple integrated shape optimization system is developed and used to optimize the design of the inner frame shape of a three-axis test table. The result shows that the method converges well, and the system is stable and reliable.展开更多
Legal terms is widely used in varied law-related activities.However,it can be easily found that it is the professionalism of legal language that have results into the appearance of its discourse hegemony and the socia...Legal terms is widely used in varied law-related activities.However,it can be easily found that it is the professionalism of legal language that have results into the appearance of its discourse hegemony and the social integration function regarding the nature of law’s social command and dispute settlement mechanism at large.Therefore,there is a need to analyze the operation of legal language and its whole influence upon individuals and certain human groups to figure out the means of improvement and optimization to better serve the Chinese rule of legal modernization drive plus the facilitation of social harmony.展开更多
电-气综合能源系统(integrated energy system,IES)的发展有助于提高能源效率并支撑可持续能源转型。电力网络和天然气网络通常隶属于不同的运营主体,这制约了IES的能源利用效率和多能互济协同。在此背景下,提出一种各能源子系统独立优...电-气综合能源系统(integrated energy system,IES)的发展有助于提高能源效率并支撑可持续能源转型。电力网络和天然气网络通常隶属于不同的运营主体,这制约了IES的能源利用效率和多能互济协同。在此背景下,提出一种各能源子系统独立优化的分布式最优调度方法。建立了电力网络潮流约束、天然气网络管网约束、电-气耦合约束下的IES集中式控制模型,并利用凸松弛技术和大M法对非凸约束进行了转化;基于交替方向乘子法(alternating direction method of multipliers,ADMM)对集中式控制模型进行解耦,使其转化为电力网络和天然气网络独立优化的分布式协同控制模型,并给出了电-气IES分布式控制方法的实施流程;用算例系统对所提方法的可行性和有效性做了验证。展开更多
基金CAPES(Coordenacao de Aperfeicoamento de Pessoal de Nível Superior)CNPq(Conselho Nacional de Desenvolvimento Científico e Tecnológico,grant number 161464/2013-0)for financial support.
文摘This paper proposes the use of the flexible tolerance method(FTM) modified with adaptive Nelder–Mead parameters and barrier to solve constrained optimization problems. The problems used to analyze the performance of the methods were taken from G-Suite functions, and the methods with the best performance were applied in mass integration problems. Four methods were proposed:(1) flexible tolerance method(FTM) using adaptive parameters(FTMA),(2) flexible tolerance method with scaling(FTMS) and with adaptive parameters(FTMAS),(3) FTMS including the barrier modification(MFTMS) and(4) MFTMS hybridized with PSO(MFTMS-PSO). The success rates of these methods were 100%(MFTMS), 85%(MFTMS-PSO), 40%(FTMAS) and 30%(FTMA).Numerical experiments indicated that the MFTMS could efficiently and reliably improve the accuracy of global optima. In mass integration, the method was able, from current process situation, to reach the optimum process configuration that includes integration issues, which was not possible using FTM in its standard formulation. The hybridization of FTMS with PSO(without barrier), FTMS-PSO, was also able to solve mass integration problems efficiently.
基金provided by the National Natural Science Foundation of China(No.51404272)the Hunan Province Key Laboratory of Coal Resources Clean-Utilization and Mine Environment Protection(No.E21224)
文摘In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is affected by more than one mining panel, traditional PIM parameter inversion model is difficult to ensure the reliability of the results due to the complexity of rock movement. With crossover,mutation and selection operators, GA can perform a global optimization search and has high computation efficiency. Compared with the pattern search algorithm, the fitness function can avoid falling into local minima traps. GA reduces the risk of local minima traps which improves the accuracy and reliability with the mutation mechanism. Application at Xuehu colliery shows that GA can be used to inverse the PIM parameters for multi-panel surface movement observation, and reliable results can be obtained. The research provides a new way for back-analysis of PIM parameters for mining subsidence under complex conditions.
文摘In this paper,an integrated guidance and control approach is presented to improve the performance of the missile interception.The approach includes damping augmented system with attitude rate feedback to decrease the oscillation during the homing phase for missiles with low damping.In addition,physical constraints,which can affect the performance of the missile interception,such as acceleration limit,seeker’s look angle,and look angle rate constraints are considered.The integrated guidance and control problem is formulated as a convex quadratic optimization problem with equality and inequality constraints,and the solution is obtained by a primal–dual interior point method.The performance of the proposed method is verified through several numerical examples.
文摘Current machining studies have reported effects of prevalent and common factors,while ultra⁃high finish requires holistic approach to identify all factors and investigate their effects on machining of hard to machine materials.In this work,a less investigated yet important factor,roughness of the uncut surface,was studied,and its effects on the individual response,i.e.,surface finish of the machined part,were found to be significant.AISI 316,which is mainly applied in strategic areas,was selected and three effective turning factors,cutting speed(A),feed rate(B),and roughness of the uncut surface(C)on three output responses including surface roughness of the machined surface(Ra),microhardness(HV),and material removal rate(MRR),were reported.Further,single response optimization of the individual output response and multi⁃response optimization of all the three responses were carried out.Taguchi L9 orthogonal array based signal⁃to⁃noise(S/N)ratio method was used for individual response optimization,and grey relational analysis(GRA)was employed for multi⁃response optimization.Effects of the process factors on the output responses were evaluated through inclusive statistical analyses.The individual response optimization revealed that there was a considerable effect of roughness of the uncut surface on the machining performance.Results of the GRA illustrated that the speed during the cutting process and the feed rate had substantial trace on the surface integrity(indicated by Ra and HV)and production rate(indicated by MRR),while roughness of the uncut surface did not have a significant effect.
文摘Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of MOC, in the context of lEGS's optimal scheduling. Specifically, the proposed method enables flexible temporal step sizes without sacrificing accuracy, significantly reducing non-convergence due to numerical oscillations. The effectiveness of the proposed method is validated through case studies in different simulation settings.
文摘A PID parameters tuning and optimization method for a turbine engine based on the simplex search method was proposed. Taking time delay of combustion and actuator into account, a simulation model of a PID control system for a turbine engine was developed. A performance index based on the integral of absolute error （IAE） was given as an objective function of optimization. In order to avoid the sensitivity that resulted from the initial values of the simplex search method, the traditional Ziegler-Nichols method was used to tune PID parameters to obtain the initial values at first, then the simplex search method was applied to optimize PID parameters for the turbine engine. Simulation results indicate that the simplex search method is a reasonable and effective method for PID controller parameters tuning and optimization.
基金Project supported by the National Natural Science Foundation of China(No.19972059).
文摘A strategy is proposed based on the stochastic averaging method for quasi non- integrable Hamiltonian systems and the stochastic dynamical programming principle.The pro- posed strategy can be used to design nonlinear stochastic optimal control to minimize the response of quasi non-integrable Hamiltonian systems subject to Gaussian white noise excitation.By using the stochastic averaging method for quasi non-integrable Hamiltonian systems the equations of motion of a controlled quasi non-integrable Hamiltonian system is reduced to a one-dimensional av- eraged It stochastic differential equation.By using the stochastic dynamical programming princi- ple the dynamical programming equation for minimizing the response of the system is formulated. The optimal control law is derived from the dynamical programming equation and the bounded control constraints.The response of optimally controlled systems is predicted through solving the FPK equation associated with It stochastic differential equation.An example is worked out in detail to illustrate the application of the control strategy proposed.
基金supported by the National Natural Science Foundation(Grant Nos.11821202,11732004,12002077 and 12002073)the National Key Research and Development Plan(Grant No.2020YFB1709401)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.DUT21-RC(3)076 and DUT20RC(3)020)the Doctoral Scientific Research Foundation of Liaoning Province(Grant No.2021-BS-063)111 Project(Grant No.B14013).
文摘Traditional topology optimization methods often introduce weak artificial material to mimic voids to avoid the singularity of the global stiffness matrix and carry out topology optimization with a fixed finite element(FE)mesh.This treatment,however,may not only increase the computational cost for structural analysis but also lead to unfavorable numerical instabilities,especially when large deformations and dynamic/buckling behaviors are involved.In the present work,a new meshless moving morphable component-based method(ML-MMC),which structural analysis is carried out only on the solid region occupied by components,is proposed.In this approach,the coupling of discrete components is achieved through the adaptively constructed influence domain of the meshless shape function.Therefore,the singularity problem of the stiffness matrix can be naturally avoided without introducing weak artificial material.Compared with traditional methods,the number of degrees of freedoms(DOFs)can be reduced substantially under this treatment.The effectiveness of the proposed approach is also illustrated by some representative examples.
文摘The penalty function method of continuum shape optimization and its sensitivity analysis technique are presented. A relatively simple integrated shape optimization system is developed and used to optimize the design of the inner frame shape of a three-axis test table. The result shows that the method converges well, and the system is stable and reliable.
文摘Legal terms is widely used in varied law-related activities.However,it can be easily found that it is the professionalism of legal language that have results into the appearance of its discourse hegemony and the social integration function regarding the nature of law’s social command and dispute settlement mechanism at large.Therefore,there is a need to analyze the operation of legal language and its whole influence upon individuals and certain human groups to figure out the means of improvement and optimization to better serve the Chinese rule of legal modernization drive plus the facilitation of social harmony.
文摘电-气综合能源系统(integrated energy system,IES)的发展有助于提高能源效率并支撑可持续能源转型。电力网络和天然气网络通常隶属于不同的运营主体,这制约了IES的能源利用效率和多能互济协同。在此背景下,提出一种各能源子系统独立优化的分布式最优调度方法。建立了电力网络潮流约束、天然气网络管网约束、电-气耦合约束下的IES集中式控制模型,并利用凸松弛技术和大M法对非凸约束进行了转化;基于交替方向乘子法(alternating direction method of multipliers,ADMM)对集中式控制模型进行解耦,使其转化为电力网络和天然气网络独立优化的分布式协同控制模型,并给出了电-气IES分布式控制方法的实施流程;用算例系统对所提方法的可行性和有效性做了验证。
