为了提高多目标粒子群优化算法解的分布性,文中提出了一种自适应分解式多目标粒子群优化算法(Adaptive Multiobjective Particle Swarm Optimization based on Decomposed Archive,AMOPSO-DA).首先,设计了一种基于优化解空间分布信息的...为了提高多目标粒子群优化算法解的分布性,文中提出了一种自适应分解式多目标粒子群优化算法(Adaptive Multiobjective Particle Swarm Optimization based on Decomposed Archive,AMOPSO-DA).首先,设计了一种基于优化解空间分布信息的外部档案更新策略,有效提升了AMOPSO-DA的空间搜索能力;其次,提出了一种基于粒子进化方向信息的飞行参数调整方法,有效平衡了AMOPSO-DA的探索和开发能力.最后,将提出的AMOPSO-DA应用于多目标优化问题,实验结果表明,文中提出的AMOPSO-DA能够获得分布性较好的优化解.展开更多
With the rapid load increase in some countries such as China, power grids are becoming more strongly interconnected, and the differences between peak and valley loads are also increasing. As a result, some bulk power ...With the rapid load increase in some countries such as China, power grids are becoming more strongly interconnected, and the differences between peak and valley loads are also increasing. As a result, some bulk power systems are facing high voltage limit violations during light-load periods. This paper proposes to utilize transmission switching(TS) to eliminate voltage violations. The TS problem is formed as a mixed-integer nonlinear program(MINLP) with AC power flow constraints and binary variables. The proposed MINLP problem is non-deterministic polynomial hard.To efficiently solve the problem, a decomposition approach is developed. This approach decomposes the original problem into a mixedinteger linear programming master problem and an AC optimal power flow slave problem that is used to check the AC feasibility. Prevention of islanding is also taken into consideration to ensure the feasibility of the TS results.The modified IEEE 39-bus and IEEE 57-bus test systems are used to demonstrate the applicability and effectiveness of the proposed method.展开更多
Retrofitting a historic building under different national goals involves multiple objectives,constraints,and numerous potential measures and packages,therefore it is time-consuming and challenging during the early des...Retrofitting a historic building under different national goals involves multiple objectives,constraints,and numerous potential measures and packages,therefore it is time-consuming and challenging during the early design stage.This study introduces a systematic retrofitting approach that incorporates standard measures for the building envelope(walls,windows,roof),as well as the heating,cooling,and lighting systems.Three retrofit objectives are delineated based on prevailing Chinese standards.The retrofit measures function as genes to optimize energy-savings,carbon emissions,and net present value(NPV)by employing a log-additive decomposition approach through energy simulation techniques and NSGA-II,yielding 185,163,and 8 solutions.Subsequently,a weighted sum method is proposed to derive optimal solutions across multiple scenarios.The framework is applied to a courtyard building in Nanjing,China,and the outcomes of the implementation are scrutinized to ascertain the optimal retrofit package under various scenarios.Through this retrofit,energy consumption can be diminished by up to 63.62%,resulting in an NPV growth of 151.84%,and maximum rate of 60.48%carbon reduction.These three result values not only indicate that the optimal values are achieved in these three aspects of energy saving,carbon reduction and economy,but also show the possibility of possible equilibrium in this multi-objective optimization problem.The framework proposed in this study effectively addresses the multi-objective optimization challenge in building renovation by employing a reliable optimization algorithm with a computationally efficient reduced-order model.It provides valuable insights and recommendations for optimizing energy retrofit strategies and meeting various performance objectives.展开更多
The performance of Ce-OMS-2 catalysts was improved by tuning the fill percentage in the hydrothermal synthesis process to increase the oxygen vacancy density.The Ce-OMS-2 samples were prepared with different fill perc...The performance of Ce-OMS-2 catalysts was improved by tuning the fill percentage in the hydrothermal synthesis process to increase the oxygen vacancy density.The Ce-OMS-2 samples were prepared with different fill percentages by means of a hydrothermal approach(i.e.80%,70%,50%and 30%).Ce-OMS-2 with 80%fill percentage(Ce-OMS-2-80%)showed ozone conversion of 97%,and a lifetime experiment carried out for more than20 days showed that the activity of the catalyst still remained satisfactorily high(91%).For Ce-OMS-2-80%,Mn ions in the framework as well as K ions in the tunnel sites were replaced by Ce^4+,while for the others only Mn ions were replaced.O2-TPD and H2-TPR measurements proved that the Ce-OMS-2-80%catalyst possessed the greatest number of mobile surface oxygen species.XPS and XAFS showed that increasing the fill percentage can reduce the AOS of Mn and augment the amount of oxygen vacancies.The active sites,which accelerate the elimination of O3,can be enriched by increasing the oxygen vacancies.These findings indicate that increasing ozone removal can be achieved by tuning the fill percentage in the hydrothermal synthesis process.展开更多
It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria v...It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria vector. A composition mechanism is used to evaluate the object as a whole at the top level. The problem is solved by the method of nested scalar convolutions of vector-valued criteria. The methodology of the problem solving is based on the complementarity principle by N. Bohr and the theorem of incompleteness by K. G?del. An example is presented that helps the reader digest some of the intricacies in the methodology.展开更多
Parallel implementation of algorithm of numerical solution of Navier-Stokes equations for large eddy simulation (LES) of turbulence is presented in this research. The Dynamic Smagorinsky model is applied for sub-grid ...Parallel implementation of algorithm of numerical solution of Navier-Stokes equations for large eddy simulation (LES) of turbulence is presented in this research. The Dynamic Smagorinsky model is applied for sub-grid simulation of turbulence. The numerical algorithm was worked out using a scheme of splitting on physical parameters. At the first stage it is supposed that carrying over movement amount takes place only due to convection and diffusion. Intermediate field of velocity is determined by method of fractional steps by using Thomas algorithm (tridiaginal matrix algorithm). At the second stage found intermediate field of velocity is used for determination of the field of pressure. Three dimensional Poisson equation for the field of pressure is solved using upper relaxation method. Moreover various ways of geometrical decomposition for parallel numerical solution of three dimensional Poisson equations are investigated.展开更多
Previous work studied a production system including multiple stations (or workshops) consisting of an entry station, a set of workstations, an exit station, and a central station, which could be arranged in any confi...Previous work studied a production system including multiple stations (or workshops) consisting of an entry station, a set of workstations, an exit station, and a central station, which could be arranged in any configuration. The central station was introduced into the production system to relax the environment. In this paper, the central station is eliminated. The entry station and all workstations have limited local buffers. A workstation can choose either a buffer or a kanban mechanism to control its work-in-process (WIP). The production system was modeled as a queueing network with blocking in a general configuration. A symmetrical decomposition approach was developed to analyze the production system. The simulation result shows that the decomposition approach works well. Comparison of the new production systems with modified production systems having a common buffer shows that the key for implementing just-in-time production systems is to reduce the uncertainty.展开更多
Calculation of eigen-solutions plays an important role in the small signal stability analysis of power systems.In this paper,a novel approach based on matrix perturbation theory is proposed for the calculation of eige...Calculation of eigen-solutions plays an important role in the small signal stability analysis of power systems.In this paper,a novel approach based on matrix perturbation theory is proposed for the calculation of eigen-solutions in a perturbed system.Rigorous theoretical analysis is conducted on the solution of distinct,multiple,and close eigen-solutions,respectively,under perturbations of parameters.The computational flowchart of the unified solution of eigen-solutions is then proposed,aimed toward obtaining eigen-solutions of a perturbed system directly with algebraic formulas without solving an eigenvalue problem repeatedly.Finally,the effectiveness of the matrix perturbation based approach for eigen-solutions’calculation in power systems is verified by numerical examples on a two-area four-machine system.展开更多
文摘为了提高多目标粒子群优化算法解的分布性,文中提出了一种自适应分解式多目标粒子群优化算法(Adaptive Multiobjective Particle Swarm Optimization based on Decomposed Archive,AMOPSO-DA).首先,设计了一种基于优化解空间分布信息的外部档案更新策略,有效提升了AMOPSO-DA的空间搜索能力;其次,提出了一种基于粒子进化方向信息的飞行参数调整方法,有效平衡了AMOPSO-DA的探索和开发能力.最后,将提出的AMOPSO-DA应用于多目标优化问题,实验结果表明,文中提出的AMOPSO-DA能够获得分布性较好的优化解.
文摘With the rapid load increase in some countries such as China, power grids are becoming more strongly interconnected, and the differences between peak and valley loads are also increasing. As a result, some bulk power systems are facing high voltage limit violations during light-load periods. This paper proposes to utilize transmission switching(TS) to eliminate voltage violations. The TS problem is formed as a mixed-integer nonlinear program(MINLP) with AC power flow constraints and binary variables. The proposed MINLP problem is non-deterministic polynomial hard.To efficiently solve the problem, a decomposition approach is developed. This approach decomposes the original problem into a mixedinteger linear programming master problem and an AC optimal power flow slave problem that is used to check the AC feasibility. Prevention of islanding is also taken into consideration to ensure the feasibility of the TS results.The modified IEEE 39-bus and IEEE 57-bus test systems are used to demonstrate the applicability and effectiveness of the proposed method.
基金the National Key R&D Program-Strategic Scientific and Technological Innovation Cooperation(#2022YFE0208600)National Science and Foundation of China(#52208011)+1 种基金the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(HZQB-KCZYB-2020083)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_0034).
文摘Retrofitting a historic building under different national goals involves multiple objectives,constraints,and numerous potential measures and packages,therefore it is time-consuming and challenging during the early design stage.This study introduces a systematic retrofitting approach that incorporates standard measures for the building envelope(walls,windows,roof),as well as the heating,cooling,and lighting systems.Three retrofit objectives are delineated based on prevailing Chinese standards.The retrofit measures function as genes to optimize energy-savings,carbon emissions,and net present value(NPV)by employing a log-additive decomposition approach through energy simulation techniques and NSGA-II,yielding 185,163,and 8 solutions.Subsequently,a weighted sum method is proposed to derive optimal solutions across multiple scenarios.The framework is applied to a courtyard building in Nanjing,China,and the outcomes of the implementation are scrutinized to ascertain the optimal retrofit package under various scenarios.Through this retrofit,energy consumption can be diminished by up to 63.62%,resulting in an NPV growth of 151.84%,and maximum rate of 60.48%carbon reduction.These three result values not only indicate that the optimal values are achieved in these three aspects of energy saving,carbon reduction and economy,but also show the possibility of possible equilibrium in this multi-objective optimization problem.The framework proposed in this study effectively addresses the multi-objective optimization challenge in building renovation by employing a reliable optimization algorithm with a computationally efficient reduced-order model.It provides valuable insights and recommendations for optimizing energy retrofit strategies and meeting various performance objectives.
基金supported by the National Key R&D Program of China(Nos.2016YFC0207104,2017YFC0211802,and2016YFC0209305)the National Natural Science Foundation of China(NSFC)(No.21876191)+1 种基金the Youth Innovation Promotion Association,CAS(No.2017064)the Science and Technology Project of the Education Department of Jiangxi Province(No.GJJ151258)
文摘The performance of Ce-OMS-2 catalysts was improved by tuning the fill percentage in the hydrothermal synthesis process to increase the oxygen vacancy density.The Ce-OMS-2 samples were prepared with different fill percentages by means of a hydrothermal approach(i.e.80%,70%,50%and 30%).Ce-OMS-2 with 80%fill percentage(Ce-OMS-2-80%)showed ozone conversion of 97%,and a lifetime experiment carried out for more than20 days showed that the activity of the catalyst still remained satisfactorily high(91%).For Ce-OMS-2-80%,Mn ions in the framework as well as K ions in the tunnel sites were replaced by Ce^4+,while for the others only Mn ions were replaced.O2-TPD and H2-TPR measurements proved that the Ce-OMS-2-80%catalyst possessed the greatest number of mobile surface oxygen species.XPS and XAFS showed that increasing the fill percentage can reduce the AOS of Mn and augment the amount of oxygen vacancies.The active sites,which accelerate the elimination of O3,can be enriched by increasing the oxygen vacancies.These findings indicate that increasing ozone removal can be achieved by tuning the fill percentage in the hydrothermal synthesis process.
文摘It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria vector. A composition mechanism is used to evaluate the object as a whole at the top level. The problem is solved by the method of nested scalar convolutions of vector-valued criteria. The methodology of the problem solving is based on the complementarity principle by N. Bohr and the theorem of incompleteness by K. G?del. An example is presented that helps the reader digest some of the intricacies in the methodology.
文摘Parallel implementation of algorithm of numerical solution of Navier-Stokes equations for large eddy simulation (LES) of turbulence is presented in this research. The Dynamic Smagorinsky model is applied for sub-grid simulation of turbulence. The numerical algorithm was worked out using a scheme of splitting on physical parameters. At the first stage it is supposed that carrying over movement amount takes place only due to convection and diffusion. Intermediate field of velocity is determined by method of fractional steps by using Thomas algorithm (tridiaginal matrix algorithm). At the second stage found intermediate field of velocity is used for determination of the field of pressure. Three dimensional Poisson equation for the field of pressure is solved using upper relaxation method. Moreover various ways of geometrical decomposition for parallel numerical solution of three dimensional Poisson equations are investigated.
基金Supported by the National Natural Science Foundationof China(No. 79930 0 70)
文摘Previous work studied a production system including multiple stations (or workshops) consisting of an entry station, a set of workstations, an exit station, and a central station, which could be arranged in any configuration. The central station was introduced into the production system to relax the environment. In this paper, the central station is eliminated. The entry station and all workstations have limited local buffers. A workstation can choose either a buffer or a kanban mechanism to control its work-in-process (WIP). The production system was modeled as a queueing network with blocking in a general configuration. A symmetrical decomposition approach was developed to analyze the production system. The simulation result shows that the decomposition approach works well. Comparison of the new production systems with modified production systems having a common buffer shows that the key for implementing just-in-time production systems is to reduce the uncertainty.
基金supported in part by the National Science Foundation of United States(NSF)(Grant No.0844707)in part by the International S&T Cooperation Program of China(ISTCP)(Grant No.2013DFA60930)
文摘Calculation of eigen-solutions plays an important role in the small signal stability analysis of power systems.In this paper,a novel approach based on matrix perturbation theory is proposed for the calculation of eigen-solutions in a perturbed system.Rigorous theoretical analysis is conducted on the solution of distinct,multiple,and close eigen-solutions,respectively,under perturbations of parameters.The computational flowchart of the unified solution of eigen-solutions is then proposed,aimed toward obtaining eigen-solutions of a perturbed system directly with algebraic formulas without solving an eigenvalue problem repeatedly.Finally,the effectiveness of the matrix perturbation based approach for eigen-solutions’calculation in power systems is verified by numerical examples on a two-area four-machine system.
