Tourists,as the main beneficiary of historical block protection and tourism development,are considered qualified to speak on the matter of the preservation of space quality and regional characteristics.The study estab...Tourists,as the main beneficiary of historical block protection and tourism development,are considered qualified to speak on the matter of the preservation of space quality and regional characteristics.The study established a questionnaire using semantic analysis to investigate and evaluate tourists’ perspective of various spatial elements in Beijing’s three historical blocks.Factor analysis and IPA method was introduced to explore how various spatial elements affected the overall environmental perception of tourists.Based on the relative importance of spatial elements,suggestions for optimizing the space of historical blocks were proposed.The study found that:①The overall evaluation of various spatial elements of the historical block was relatively positive,and only the "environmental atmosphere" was closer to the negative evaluation,indicating that most tourists think the environment was too noisy;②All spatial elements can be classified into three indicators:"visual experience","street form" and "perception of regional characteristics";③Landscape planting and space interface needed to be improved first,followed by ground pavement,traffic organization,and advertisement signboard.The research provides a theoretical foundation for reducing the damage caused by improper tourism development behaviors,further improving the spatial quality of historical blocks,and enhancing tourists’ satisfaction of the historical environment.展开更多
Considering the defects of conventional optimization methods, a novel optimization algorithm is introduced in this paper. Target space partitioning method is used in this algorithm to solve multi-objective optimizatio...Considering the defects of conventional optimization methods, a novel optimization algorithm is introduced in this paper. Target space partitioning method is used in this algorithm to solve multi-objective optimization problem, thus achieve the coherent solution which can meet the requirements of all target functions, and improve the population's overall evolution level. The algorithm which guarantees diversity preservation and fast convergence to the Pareto set is applied to structural optimization problems. The empirical analysis supports the algorithm and gives an example with program.展开更多
Concepts for a virtual 3D space and a hyper-sphere are proposed and the formulae for determining the computable nodes of the mesh are derived.Then a new optimization design method('Virtual Mesh Method'or V.M.M...Concepts for a virtual 3D space and a hyper-sphere are proposed and the formulae for determining the computable nodes of the mesh are derived.Then a new optimization design method('Virtual Mesh Method'or V.M.M)is developed.Three examples are given,showing that the method proposed is especially suitable for the optimized design of complex structures,and that the global approximate optimal solution can be searched with remarkably reduced computational work.展开更多
Underground space resources are important for the purposes of urban sustainable development and are a significant means by which to realize three-dimensional urban development.A reasonable and scientific evaluation of...Underground space resources are important for the purposes of urban sustainable development and are a significant means by which to realize three-dimensional urban development.A reasonable and scientific evaluation of underground space resources is the foundation for the rational use of land resources and urban planning.On the basis of the geological conditions used by preceding researchers,this study adds the analysis of two influencing factors of social and economic value,alongside existing facilities and protection needs.The evaluation index is quantified and the comprehensive quality evaluation system of underground space resources is constructed.Finally,taking the Nanshan District of Shenzhen as an example,the evaluation of underground space resources is carried out.The results show that for shallow underground space,the comprehensive quality of underground space resources development in Nanshan District is generally high.Nantou,Nanshan and Yuehai streets are recommended as areas to actively develop underground space,whereas the Qianhai and Houhai areas are recommended to be used with caution in the development and construction of their underground space.In addition,this study also provides a reference for the purposes of underground space planning in the Nanshan district of Shenzhen.展开更多
In this paper, we propose a retrospective filter trust region algorithm for unconstrained optimization, which is based on the framework of the retrospective trust region method and associated with the technique of the...In this paper, we propose a retrospective filter trust region algorithm for unconstrained optimization, which is based on the framework of the retrospective trust region method and associated with the technique of the multi-dimensional filter. The new algorithm gives a good estimation of trust region radius, relaxes the condition of accepting a trial step for the usual trust region methods. Under reasonable assumptions, we analyze the global convergence of the new method and report the preliminary results of numerical tests. We compare the results with those of the basic trust region algorithm, the filter trust region algorithm and the retrospective trust region algorithm, which shows the effectiveness of the new algorithm.展开更多
When designing modern cellular networks, it is challenging to account for many contradictory criteria and constantly changing external conditions of the networks (e.g., traffic). We need to solve multicriteria problem...When designing modern cellular networks, it is challenging to account for many contradictory criteria and constantly changing external conditions of the networks (e.g., traffic). We need to solve multicriteria problems with high-dimensional vectors of parameters. A prerequisite to solution of these problems is correct determination of the feasible solution set, which is directly related to the statement of optimization problem. This is a major challenge in all multicriteria engineering optimization problems and represents significant difficulties for the expert. In this paper, we show how to define the feasible solution set for cellular network optimal design problems and thus answer the fundamental question of where to search for optimal solutions in such problems. We use the Parameter Space Investigation (PSI) method implemented in the Multicriteria Optimization and Vector Identification (MOVI) software system and apply it to a mathematical model of cellular network. In addition to developing methodology for stating and solving the problem of multicriteria optimization of cellular network, we have found that 1) defining the feasible solution set is directly related to the correct statement of the optimization problem, 2) once the feasible solution set has been determined, the criteria convolution can be applied to find the optimal solution in the feasible solution set, 3) it is possible to perform online tuning of the cellular network parameters.展开更多
Through the analysis of the overall landscape,revetments and roads and plant landscape,10 evaluation factors were determined.The comprehensive evaluation model for the campus space of Anhui Xinhua University was const...Through the analysis of the overall landscape,revetments and roads and plant landscape,10 evaluation factors were determined.The comprehensive evaluation model for the campus space of Anhui Xinhua University was constructed by analytic hierarchy process(AHP).The results showed that revetment safety,road convenience,plant disease resistance and campus activity space were important factors affecting the spatial form planning of campus.Through the comparative analysis of the collected data,optimization suggestions were put forward to provide a basis for the establishment of“people-oriented”campus open space system.展开更多
Non-contact debris removal methods are fuel-efficient in a single operation compared to contact-based strategies as spacecraft don’t need to match debris velocity.To comprehensively analyze this scheme,maneuvering sc...Non-contact debris removal methods are fuel-efficient in a single operation compared to contact-based strategies as spacecraft don’t need to match debris velocity.To comprehensively analyze this scheme,maneuvering schemes for maximum debris removal with minimum fuel consumption,including task assignment,sequence planning,and trajectory planning,must be formulated.The coupling between variables’dimensions and optimization results in task assignment poses challenges,as debris removal is repetitive and uncertain,leading to a vast search space.This paper proposes a novel Greedy Randomized Adaptive Search Procedure with Large Neighborhood and Crossover Mechanisms(GRASP-LNCM)to address this problem.The hybrid dynamic iteration mechanism improves computational efficiency and enhances the optimality of results.The model innovatively considers unsuccessful single removal by using a quantitative method to assess removal percentage.In addition,to improve the efficiency of sequence and trajectory planning,a Suboptimal Search Algorithm(SSA)based on the Lambert property and accelerated Multi-Revolution Lambert Problem(MRLP)solving strategy is established.Finally,a real Iridium-33 debris removal mission is studied.The simulation demonstrates that the proposed algorithm achieves state-of-the-art performance in several typical scenarios.Compared to the contact-based scheme,the new one is simpler,saving more fuel under certain conditions.展开更多
This paper delineates a conventional buck converter controlled by optimized PID controller where Genetic Algorithm (GA) is employed with a view to enhancing the performance by analyzing the performance parameters. Gen...This paper delineates a conventional buck converter controlled by optimized PID controller where Genetic Algorithm (GA) is employed with a view to enhancing the performance by analyzing the performance parameters. Genetic Algorithm is a probabilistic search algorithm which is substantially used as an optimization technique in power electronics. A bunch of modifications have already been introduced to enhance the performance depending upon the applications. However, in this paper, modified genetic algorithm has been used in order to tune the key parameters in the converter. Hence, an analysis is carried out where the performance of the converter is illustrated in terms of rise time, settling time and percentage of overshoot by deploying GA based PID controller and the overall comparative study is presented. Responses of the overall system are accumulated through rigorous simulation in MATLAB environment.展开更多
Due to operational or physical considerations, standard factorial and response surface method （RSM） design of experiments （DOE） often prove to be unsuitable. In such cases a computer-generated statistically-optima...Due to operational or physical considerations, standard factorial and response surface method （RSM） design of experiments （DOE） often prove to be unsuitable. In such cases a computer-generated statistically-optimal design fills the breech. This article explores vital mathematical properties for evaluating alternative designs with a focus on what is really important for industrial experimenters. To assess ＂goodness of design＂ such evaluations must consider the model choice, specific optimality criteria （in particular D and I）, precision of estimation based on the fraction of design space （FDS）, the number of runs to achieve required precision, lack-of-fit testing, and so forth. With a focus on RSM, all these issues are considered at a practical level, keeping engineers and scientists in mind. This brings to the forefront such considerations as subject-matter knowledge from first principles and experience, factor choice and the feasibility of the experiment design.展开更多
It is necessary to decrease the weight of space satellites, while maintaining their stiffness. To achieve this weight reduction, many structures, such as honeycomb and isogrid, have been reported in the literature. In...It is necessary to decrease the weight of space satellites, while maintaining their stiffness. To achieve this weight reduction, many structures, such as honeycomb and isogrid, have been reported in the literature. In this paper, the diamond rib method, a mechanical design method for improving the stiffness of structures, is introduced. By applying this method to a small space satellite, we propose a new structure called the “Diamond Rib Structure”. This structure significantly improves the ability to withstand the vibrational disturbances in a rocket fairing.展开更多
When horizontal well staged cluster fracturing is applied in shale gas reservoirs,the cluster spacing is essential to fracturing performance.If the cluster spacing is too small,the stimulated area between major fractu...When horizontal well staged cluster fracturing is applied in shale gas reservoirs,the cluster spacing is essential to fracturing performance.If the cluster spacing is too small,the stimulated area between major fractures will be overlapped,and the efficiency of fracturing stimulation will be decreased.If the cluster spacing is too large,the area between major fractures cannot be stimulated completely and reservoir recovery extent will be adversely impacted.At present,cluster spacing design is mainly based on the static model with the potential reservoir stimulation area as the target,and there is no cluster spacing design method in accordance with the actual fracturing process and targets dynamic stimulated reservoir volume(SRV).In this paper,a dynamic SRV calculation model for cluster fracture propagation was established by analyzing the coupling mechanisms among fracture propagation,fracturingfluid loss and stress.Then,the cluster spacing was optimized to reach the target of the optimal SRVs.This model was applied for validation on site in the Jiaoshiba shale gasfield in the Fuling area of the Sichuan Basin.The key geological engineering parameters influencing the optimal cluster spacing intervals were analyzed.The reference charts for the optimal cluster spacing design were prepared based on the geological characteristics of south and north blocks in the Jiaoshiba shale gasfield.It is concluded that the cluster spacing optimal design method proposed in this paper is of great significance in overcoming the blindness in current cluster perforation design and guiding the optimal design of volume fracturing in shale gas reservoirs.展开更多
This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than ...This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than the null space step for the most cases,the proposed algorithm computes null steps more often than range space step. Moreover,the new algorithm is based on the reduced Hessian SQP method. Global convergence ofthe proposed algorithm is proved. The effectiveness of the method is demonstrated bysome numerical examples.展开更多
基金Sponsored by Key Project of National Social Science Foundation of China(19CZS065)Key Research and Development Program of Hainan Province(ZDYF2019231).
文摘Tourists,as the main beneficiary of historical block protection and tourism development,are considered qualified to speak on the matter of the preservation of space quality and regional characteristics.The study established a questionnaire using semantic analysis to investigate and evaluate tourists’ perspective of various spatial elements in Beijing’s three historical blocks.Factor analysis and IPA method was introduced to explore how various spatial elements affected the overall environmental perception of tourists.Based on the relative importance of spatial elements,suggestions for optimizing the space of historical blocks were proposed.The study found that:①The overall evaluation of various spatial elements of the historical block was relatively positive,and only the "environmental atmosphere" was closer to the negative evaluation,indicating that most tourists think the environment was too noisy;②All spatial elements can be classified into three indicators:"visual experience","street form" and "perception of regional characteristics";③Landscape planting and space interface needed to be improved first,followed by ground pavement,traffic organization,and advertisement signboard.The research provides a theoretical foundation for reducing the damage caused by improper tourism development behaviors,further improving the spatial quality of historical blocks,and enhancing tourists’ satisfaction of the historical environment.
基金National Natural Science Foundations of China (No. 60970004, No. 60743010)Natural Science Foundation of ShandongProvince, China (No. Z2008G02)
文摘Considering the defects of conventional optimization methods, a novel optimization algorithm is introduced in this paper. Target space partitioning method is used in this algorithm to solve multi-objective optimization problem, thus achieve the coherent solution which can meet the requirements of all target functions, and improve the population's overall evolution level. The algorithm which guarantees diversity preservation and fast convergence to the Pareto set is applied to structural optimization problems. The empirical analysis supports the algorithm and gives an example with program.
基金Project supported by the Natural Science Foundation of Henan Province,China(No.0311010400).
文摘Concepts for a virtual 3D space and a hyper-sphere are proposed and the formulae for determining the computable nodes of the mesh are derived.Then a new optimization design method('Virtual Mesh Method'or V.M.M)is developed.Three examples are given,showing that the method proposed is especially suitable for the optimized design of complex structures,and that the global approximate optimal solution can be searched with remarkably reduced computational work.
基金The project of the Chinese Geological Survey'Survey of geothermal resources in the northern branch of Luoxiao Mountains'(Grant No.DD20221677-2)the special funds for basic scientific research business'Research on dome structure and circulation mechanism of annular hot spring chain'(Grant No.JKY202004)funded this research project。
文摘Underground space resources are important for the purposes of urban sustainable development and are a significant means by which to realize three-dimensional urban development.A reasonable and scientific evaluation of underground space resources is the foundation for the rational use of land resources and urban planning.On the basis of the geological conditions used by preceding researchers,this study adds the analysis of two influencing factors of social and economic value,alongside existing facilities and protection needs.The evaluation index is quantified and the comprehensive quality evaluation system of underground space resources is constructed.Finally,taking the Nanshan District of Shenzhen as an example,the evaluation of underground space resources is carried out.The results show that for shallow underground space,the comprehensive quality of underground space resources development in Nanshan District is generally high.Nantou,Nanshan and Yuehai streets are recommended as areas to actively develop underground space,whereas the Qianhai and Houhai areas are recommended to be used with caution in the development and construction of their underground space.In addition,this study also provides a reference for the purposes of underground space planning in the Nanshan district of Shenzhen.
文摘In this paper, we propose a retrospective filter trust region algorithm for unconstrained optimization, which is based on the framework of the retrospective trust region method and associated with the technique of the multi-dimensional filter. The new algorithm gives a good estimation of trust region radius, relaxes the condition of accepting a trial step for the usual trust region methods. Under reasonable assumptions, we analyze the global convergence of the new method and report the preliminary results of numerical tests. We compare the results with those of the basic trust region algorithm, the filter trust region algorithm and the retrospective trust region algorithm, which shows the effectiveness of the new algorithm.
文摘When designing modern cellular networks, it is challenging to account for many contradictory criteria and constantly changing external conditions of the networks (e.g., traffic). We need to solve multicriteria problems with high-dimensional vectors of parameters. A prerequisite to solution of these problems is correct determination of the feasible solution set, which is directly related to the statement of optimization problem. This is a major challenge in all multicriteria engineering optimization problems and represents significant difficulties for the expert. In this paper, we show how to define the feasible solution set for cellular network optimal design problems and thus answer the fundamental question of where to search for optimal solutions in such problems. We use the Parameter Space Investigation (PSI) method implemented in the Multicriteria Optimization and Vector Identification (MOVI) software system and apply it to a mathematical model of cellular network. In addition to developing methodology for stating and solving the problem of multicriteria optimization of cellular network, we have found that 1) defining the feasible solution set is directly related to the correct statement of the optimization problem, 2) once the feasible solution set has been determined, the criteria convolution can be applied to find the optimal solution in the feasible solution set, 3) it is possible to perform online tuning of the cellular network parameters.
基金by National Undergraduate Innovation Training Program of Anhui Xinhua University in 2022(202212216012)Provincial Undergraduate Innovation Training Program of Anhui Xinhua University in 2021(AH202112216119)+1 种基金Key Research Project of Natural Science in Colleges and Universities of Anhui Province(2023AH051816)General Teaching Research Project of Anhui Province(2022jyxm665).
文摘Through the analysis of the overall landscape,revetments and roads and plant landscape,10 evaluation factors were determined.The comprehensive evaluation model for the campus space of Anhui Xinhua University was constructed by analytic hierarchy process(AHP).The results showed that revetment safety,road convenience,plant disease resistance and campus activity space were important factors affecting the spatial form planning of campus.Through the comparative analysis of the collected data,optimization suggestions were put forward to provide a basis for the establishment of“people-oriented”campus open space system.
基金co-supported by the National Natural Science Foundation of China(Nos.U23B6001,62273118,12150008)the Fundamental Research Funds for the Central Universities,China(No.2023FRFK02043)+1 种基金the Natural Science Foundation of Heilongjiang Province,China(No.LH2022F023)China Aerospace Science and Technology Corporation Youth Talent Support Program.
文摘Non-contact debris removal methods are fuel-efficient in a single operation compared to contact-based strategies as spacecraft don’t need to match debris velocity.To comprehensively analyze this scheme,maneuvering schemes for maximum debris removal with minimum fuel consumption,including task assignment,sequence planning,and trajectory planning,must be formulated.The coupling between variables’dimensions and optimization results in task assignment poses challenges,as debris removal is repetitive and uncertain,leading to a vast search space.This paper proposes a novel Greedy Randomized Adaptive Search Procedure with Large Neighborhood and Crossover Mechanisms(GRASP-LNCM)to address this problem.The hybrid dynamic iteration mechanism improves computational efficiency and enhances the optimality of results.The model innovatively considers unsuccessful single removal by using a quantitative method to assess removal percentage.In addition,to improve the efficiency of sequence and trajectory planning,a Suboptimal Search Algorithm(SSA)based on the Lambert property and accelerated Multi-Revolution Lambert Problem(MRLP)solving strategy is established.Finally,a real Iridium-33 debris removal mission is studied.The simulation demonstrates that the proposed algorithm achieves state-of-the-art performance in several typical scenarios.Compared to the contact-based scheme,the new one is simpler,saving more fuel under certain conditions.
文摘This paper delineates a conventional buck converter controlled by optimized PID controller where Genetic Algorithm (GA) is employed with a view to enhancing the performance by analyzing the performance parameters. Genetic Algorithm is a probabilistic search algorithm which is substantially used as an optimization technique in power electronics. A bunch of modifications have already been introduced to enhance the performance depending upon the applications. However, in this paper, modified genetic algorithm has been used in order to tune the key parameters in the converter. Hence, an analysis is carried out where the performance of the converter is illustrated in terms of rise time, settling time and percentage of overshoot by deploying GA based PID controller and the overall comparative study is presented. Responses of the overall system are accumulated through rigorous simulation in MATLAB environment.
文摘Due to operational or physical considerations, standard factorial and response surface method （RSM） design of experiments （DOE） often prove to be unsuitable. In such cases a computer-generated statistically-optimal design fills the breech. This article explores vital mathematical properties for evaluating alternative designs with a focus on what is really important for industrial experimenters. To assess ＂goodness of design＂ such evaluations must consider the model choice, specific optimality criteria （in particular D and I）, precision of estimation based on the fraction of design space （FDS）, the number of runs to achieve required precision, lack-of-fit testing, and so forth. With a focus on RSM, all these issues are considered at a practical level, keeping engineers and scientists in mind. This brings to the forefront such considerations as subject-matter knowledge from first principles and experience, factor choice and the feasibility of the experiment design.
文摘It is necessary to decrease the weight of space satellites, while maintaining their stiffness. To achieve this weight reduction, many structures, such as honeycomb and isogrid, have been reported in the literature. In this paper, the diamond rib method, a mechanical design method for improving the stiffness of structures, is introduced. By applying this method to a small space satellite, we propose a new structure called the “Diamond Rib Structure”. This structure significantly improves the ability to withstand the vibrational disturbances in a rocket fairing.
基金Project supported by the National Natural Science Foundation for Young Scientists of China(No.51404204)National Science and Technology Major Project(No.2016ZX05060)Sinopec Research Project(No.31400026-16-ZC0607-0013).
文摘When horizontal well staged cluster fracturing is applied in shale gas reservoirs,the cluster spacing is essential to fracturing performance.If the cluster spacing is too small,the stimulated area between major fractures will be overlapped,and the efficiency of fracturing stimulation will be decreased.If the cluster spacing is too large,the area between major fractures cannot be stimulated completely and reservoir recovery extent will be adversely impacted.At present,cluster spacing design is mainly based on the static model with the potential reservoir stimulation area as the target,and there is no cluster spacing design method in accordance with the actual fracturing process and targets dynamic stimulated reservoir volume(SRV).In this paper,a dynamic SRV calculation model for cluster fracture propagation was established by analyzing the coupling mechanisms among fracture propagation,fracturingfluid loss and stress.Then,the cluster spacing was optimized to reach the target of the optimal SRVs.This model was applied for validation on site in the Jiaoshiba shale gasfield in the Fuling area of the Sichuan Basin.The key geological engineering parameters influencing the optimal cluster spacing intervals were analyzed.The reference charts for the optimal cluster spacing design were prepared based on the geological characteristics of south and north blocks in the Jiaoshiba shale gasfield.It is concluded that the cluster spacing optimal design method proposed in this paper is of great significance in overcoming the blindness in current cluster perforation design and guiding the optimal design of volume fracturing in shale gas reservoirs.
基金This research is partly supported by the Hunan Provincial Natural Science Foundtion of China and Hunan Provincial Education Foundation of China 02B021
文摘This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than the null space step for the most cases,the proposed algorithm computes null steps more often than range space step. Moreover,the new algorithm is based on the reduced Hessian SQP method. Global convergence ofthe proposed algorithm is proved. The effectiveness of the method is demonstrated bysome numerical examples.
