In feeder automation transformation there are difficulties in equipment and location selection.To help with this,an optimal layout model of feeder automation equipment oriented to the type of fault detection and local...In feeder automation transformation there are difficulties in equipment and location selection.To help with this,an optimal layout model of feeder automation equipment oriented to the type of fault detection and local action is pro-posed.It analyzes the coordination relationship of the three most common types of automation equipment,i.e.,fault indicator,over-current trip switch and non-voltage trip switch in the fault handling process,and the explicit expres-sions of power outage time caused by a fault on different layouts of the above three types of equipment are given.Given constraints of power supply reliability and the goal of minimizing the sum of equipment-related capital invest-ment and power interruption cost,a mixed-integer quadratic programming model for optimal layout is established,in which the functional failure probability of equipment is linearized using the 3δprinciple in statistics.Finally,the basic characteristics of the proposed model are illustrated by different scenarios on the IEEE RBTS-BUS6 system.It can not only take into account fault location and fault isolation to enhance user power consumption perception,but also can guide precise investment to improve the operational quality and efficiency of a power company.展开更多
An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past decades.However,few papers systematically review these researches.By analyzing existing lit...An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past decades.However,few papers systematically review these researches.By analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods applied.The process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout optimization.This paper makes a review of the fixture layout for thin-walled parts according to these three steps.First,two different kinds of optimization objectives are introduced.Researchers usually consider in-plane variations or out-of-plane deformations when designing objectives.Then,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based methods.Several common methods are discussed respectively.After that,optimization algorithms are reviewed systematically.There are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic algorithms.Finally,discussions on the current situation are provided.The research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization algorithms.Also,a new research point for fixture layout optimization is discussed.This paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.展开更多
The spacecraequipment layout optimization design(SELOD)problems with complicated performance con-straints and diversity are studied in this paper.The previous literature uses the gradient-based algorithm to obtain op...The spacecraequipment layout optimization design(SELOD)problems with complicated performance con-straints and diversity are studied in this paper.The previous literature uses the gradient-based algorithm to obtain optimized non-overlap layout schemes from randomly initialized cases eectively.However,these local optimal solutions are too dicult to jump out of their current relative geometry relationships,signicantly limiting their further improvement in performance indicators.Therefore,considering the geometric diversity of layout schemes is put forward to alleviate this limitation.First,similarity measures,including modied cosine similarity and gaussian kernel function similarity,are introduced into the layout optimization process.Then the optimization produces a set of feasible layout candidates with the most remarkable dierence in geometric distribution and the most representative schemes are sampled.Finally,these feasible geometric solutions are used as initial solutions to optimize the physical performance indicators of the spacecra,and diversied layout schemes of spacecraequipment are generated for the engineering practice.The validity and eectiveness of the proposed methodology are demonstrated by two SELOD applications.展开更多
Wind energy has been widely applied in power generation to alleviate climate problems.The wind turbine layout of a wind farm is a primary factor of impacting power conversion efficiency due to the wake effect that red...Wind energy has been widely applied in power generation to alleviate climate problems.The wind turbine layout of a wind farm is a primary factor of impacting power conversion efficiency due to the wake effect that reduces the power outputs of wind turbines located in downstream.Wind farm layout optimization(WFLO)aims to reduce the wake effect for maximizing the power outputs of the wind farm.Nevertheless,the wake effect among wind turbines increases significantly as the number of wind turbines increases in the wind farm,which severely affect power conversion efficiency.Conventional heuristic algorithms suffer from issues of low solution quality and local optimum for large-scale WFLO under complex wind scenarios.Thus,a chaotic local search-based genetic learning particle swarm optimizer(CGPSO)is proposed to optimize large-scale WFLO problems.CGPSO is tested on four larger-scale wind farms under four complex wind scenarios and compares with eight state-of-the-art algorithms.The experiment results indicate that CGPSO significantly outperforms its competitors in terms of performance,stability,and robustness.To be specific,a success and failure memories-based selection is proposed to choose a chaotic map for chaotic search local.It improves the solution quality.The parameter and search pattern of chaotic local search are also analyzed for WFLO problems.展开更多
Urban park is one of the few green spaces that retain natural traces and are easy for the elderly to reach,and it has become the main place for the elderly to carry out leisure,entertainment,physical fi tness and inte...Urban park is one of the few green spaces that retain natural traces and are easy for the elderly to reach,and it has become the main place for the elderly to carry out leisure,entertainment,physical fi tness and interpersonal activities.The reasonable layout of urban parks is of great signifi cance to improve the quality of life of the elderly in old age.In this article,using the network analysis method in ArcGIS software,the accessibility of urban parks in Xihu District of Nanchang City based on elderly walking was evaluated and analyzed,and three strategies for optimizing the layout of the urban parks were proposed,including increasing the number of urban parks,improving the urban traffic network,and strengthening urban greenway planning and construction.The research results can provide reference for the optimal layout of urban parks in Xihu District,Nanchang City,so that the urban parks can better meet the outdoor leisure needs of the elderly,and the elderly’s sense of well-being and gain is enhanced.展开更多
Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,Chi...Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.展开更多
This paper investigates the validity and shortcomings of the existing analytical solution for the ultimate bearing capacity of a pile embedded in a rock mass using the modified HoekeBrown failure criterion.Although th...This paper investigates the validity and shortcomings of the existing analytical solution for the ultimate bearing capacity of a pile embedded in a rock mass using the modified HoekeBrown failure criterion.Although this criterion is considered a reference value for empirical and numerical calculations,some limitations of its basic simplifications have not been clarified yet.This research compares the analytical results obtained from the novel discontinuity layout optimization(DLO)method and the numerical solutions from the finite difference method(FDM).The limitations of the analytical solution are considered by comparing different DLO failure modes,thus allowing for the first time a critical evaluation of its scope and conditioning for implementation.Errors of up to 40%in the bearing capacity and unrealistic failure modes are the main issues in the analytical solution.The main aspects of the DLO method are also analyzed with an emphasis on the linearization of the rock failure criterion and the accuracy resulting from the discretization size.The analysis demonstrates DLO as a very efficient and accurate tool to address the pile tip bearing capacity,presenting considerable advantages over other methods.展开更多
A hot primary-air pipe system is the bridge connecting an air-preheater with a coal mill in power generation stations.The effective geometrical configuration of the pipe network greatly affects the air flow distributi...A hot primary-air pipe system is the bridge connecting an air-preheater with a coal mill in power generation stations.The effective geometrical configuration of the pipe network greatly affects the air flow distribution and consequently influences the safe and economic operation of milling systems in power stations.In order to improve the properties of the air flow,in the present work the SIMPLEC method is used to simulate numerically the flow field for the original layout of the system.As a result,the internal mechanisms influencing the uneven pressure drop in each branch are explored and three optimization schemes are proposed accordingly.The numerical results indicate that,for the original layout,the local pressure drop of the tee section accounts for approximately 74%of the total drop of the system,with other pressure drops depending on the specific branch considered.It is shown that after optimization,a roughly balanced flow resistance and flow rate can be obtained.Compared with the original layout,the pressure drop relating to different branches is significantly reduced.展开更多
The delimitation of urban development boundaries plays an important role in optimizing the nation land space.“Double evaluation”is one of the important means to study and predict the scale of new construction land i...The delimitation of urban development boundaries plays an important role in optimizing the nation land space.“Double evaluation”is one of the important means to study and predict the scale of new construction land in the future and to determine the spatial distribution of urban construction land.This study combines the“double evaluation”with the FLUS(Future Land-Use Simulation)model to study the delimitation of the urban development boundary of Yichang.The results show that:(1)the“double evaluation”method comprehensively considers the carrying capacity of the resource environmental bear and the suitability of urban development;(2)the FLUS model can better couple the“double evaluation”method for Land Use/Land Cover(LULC)suitability evaluation,Land Use/land Cover Change(LUCC)simulation and urban development boundary delineation,and the overall accuracy of the simulation reaches 96%;(3)according to the requirements of relevant national policies,this study divides the urban development boundary of the study area into concentrated construction areas,elastic development areas and special purpose areas.This function-based division can meet the requirements of urban flexible development,ecological protection and urban safety.This research combines the FLUS model,which is widely used in the simulation of LUCC,with the double evaluation method used in China’s new round of land and space planning to obtain the result of the urban development boundary.This result is consistent with the existing plan of the study area.展开更多
As the first step of the fire/gas-detection systems of floating production storage and offloading(FPSO)units is to iden-tify leakage accidents,gas detectors play an important role in controlling the leakage risk.To im...As the first step of the fire/gas-detection systems of floating production storage and offloading(FPSO)units is to iden-tify leakage accidents,gas detectors play an important role in controlling the leakage risk.To improve the leakage scenario detection rate and reduce the cumulative risk value,this paper presents an optimization method of the gas detector placement.The probability density distribution and cumulative probability density distribution of the leakage source variables and environmental variables were calculated based on the Offshore Reliability Data and the statistical data of the relevant leakage variables.A potential leakage sce-nario set was constructed using Latin hypercube sampling.The typical FPSO leakage scenarios were analyzed through computational fluid dynamics(CFD),and the impacts of different parameters on the leakage were addressed.A series of detectors was deployed according to the simulation results.The minimization of the product of effective detection time and gas leakage volume was the risk optimization objective,and the location and number of detectors were taken as decision variables.A greedy extraction heuristic algo-rithm was used to solve the optimization problem.The results show that the optimized placement had a better monitoring effect on the leakage scenario.展开更多
Stiffened plates or shells are widely used in engineering structures as primary or secondary load-bearing components.How to design the layout and sizes of the stiffeners is of great significance for structural lightwe...Stiffened plates or shells are widely used in engineering structures as primary or secondary load-bearing components.How to design the layout and sizes of the stiffeners is of great significance for structural lightweight.In this work,a new topology optimization method for simultaneously optimizing the layout and cross-section topology of the stiffeners is developed to solve this issue.The stilfeners and base plates are modeled by the beam and shell elements,respectively,significantly reducing the computational cost.The Giavotto beam theory,instead of the widely employed Euler or Timoshenko beam theory,is applied to model the stiffeners for considering the warping deformation in evaluating the section stiffness of the beam.A multi-scale topology optimization model is established by simultaneously optimizing the layout of the beam and the topology of the cross-section.The design space is significantly expanded by optimizing these two types of design variables.Several numerical examples are applied to illustrate the validity and effectiveness of the proposed method.The results show that the proposed two-scale optimization approach can generate better designs than the single-scale method.展开更多
This paper presents a developed meta-heuristic algorithm to optimize the shear walls of tall reinforced concrete buildings.These types of walls are considered as lateral resistant elements.In this paper,Quantum Charge...This paper presents a developed meta-heuristic algorithm to optimize the shear walls of tall reinforced concrete buildings.These types of walls are considered as lateral resistant elements.In this paper,Quantum Charged System Search(QCSS)algorithm is presented as a new optimization method and used to improve the convergence capability of the original Charged System Search.The cost of tall building is taken as the objective function.Since the design of the lateral system plays a major role in the performance of the tall buildings,this paper proposes a unique computational technique that,unlike available works,focuses on structural efficiency or architectural design.This technique considers both structural and architectural requirements such as minimum structural costs,torsional effects,flexural and shear resistance,lateral deflection,openings and accessibility.The robustness of the new algorithm is demonstrated by comparing the outcomes of the QCSS with those of its standard algorithm.展开更多
The fluctuation of wind power brings great challenges to the secure,stable,and cost-efficient operation of the power system.Because of the time-correlation of wind speed and the wake effect of wind turbines,the layout...The fluctuation of wind power brings great challenges to the secure,stable,and cost-efficient operation of the power system.Because of the time-correlation of wind speed and the wake effect of wind turbines,the layout of wind farm has a significant impact on the wind power sequential fluctuation.In order to reduce the fluctuation of wind power and improve the operation security with lower operating cost,a bi-objective layout optimization model for multiple wind farms considering the sequential fluctuation of wind power is proposed in this paper.The goal is to determine the optimal installed capacity of wind farms and the location of wind turbines.The proposed model maximizes the energy production and minimizes the fluctuation of wind power simultaneously.To improve the accuracy of wind speed estimation and hence the power calculation,the timeshifting of wind speed between the wind tower and turbines’locations is also considered.A uniform design based two-stage genetic algorithm is developed for the solution of the proposed model.Case studies demonstrate the effectiveness of this proposed model.展开更多
This paper explores the influence of the State Capital Investing and Operating Company(SCIOC)pilot reform on SOE bailout using a staggered differencein-differences model.Based on a sample of listed SOEs during 2011-20...This paper explores the influence of the State Capital Investing and Operating Company(SCIOC)pilot reform on SOE bailout using a staggered differencein-differences model.Based on a sample of listed SOEs during 2011-2018,we find that when the real controllers of listed SOEs enter the list of SCIOCs,soft budget constraints are alleviated and listed subsidiaries are less likely to become distressed.Mechanism tests indicate that SCIOCs help distressed firms through exiting the market,reducing bank loans,enhancing corporate governance,and improving operating efficiency.Heterogeneity tests show that the effect of SCIOC establishment is more significant in central and western regions,in public welfare and special function industries,for central SCIOCs,for state capital investing companies,when firms are organized in more layers,and for firms that engage in M&As.The empirical results show that the implementation of SCIOCs benefits both micro-enterprise development and state capital layout optimization.展开更多
Smart morphing wing, which is equipped with smart materials and able to change structural geometry adaptively, can further improve aerodynamic efficiency of aircraft. This paper presents a new integrated layout and to...Smart morphing wing, which is equipped with smart materials and able to change structural geometry adaptively, can further improve aerodynamic efficiency of aircraft. This paper presents a new integrated layout and topology optimization design for morphing wing driven by shape memory alloys(SMAs). By simultaneously optimizing the layout of smart actuators and topology of wing substrate, the ultimately determined configuration can achieve smooth, continuous and accurate geometric shape changes. In addition, aerodynamic analysis is carried out to compare smart morphing wing with traditional hinged airfoil. Finally, the optimized smart wing structure is constructed and tested to demonstrate and verify the morphing functionality. Application setbacks are also pointed out for further investigation.展开更多
Climate change within the urban contexts is a crisis that cities are confronting globally.This issue poses numerous negative consequences such as thermal discomfort and increased energy usage within the building secto...Climate change within the urban contexts is a crisis that cities are confronting globally.This issue poses numerous negative consequences such as thermal discomfort and increased energy usage within the building sector.This is especially the case in Western Sydney,Australia,where the average maximum temperature has risen by 7—8℃ within the past 30 years.This increase in temperature is highly concerning,since this region is witnessing rapid urban and infrastructural development and is proposed as the third-largest economy of Australia.Temperature changes in this region will also result in considerably increasing the electricity used for cooling purposes.This paper presents a parametric approach driven multi-objective optimization methodology to discover optimum design solution based on the urban microclimate and cooling energy demand of multi-functional buildings within this urban context.Mitigation measures including a range of design factors at both building(typology and window to wall ratio)and urban scales(aspect ratio and urban grid rotation)are further suggested for developing context sensitive optimum urban layouts.The resultant solutions indicate an improvement in urban thermal comfort,cooling and heating energy use by up to 25.85%,72.76%,and 93.67%,respectively.展开更多
The accurate estimation of the end-effector’s pose in large operating spaces is the key for the mobile manipulator to realize efficient manufacturing of large and complex components.We propose a novel pose tracking m...The accurate estimation of the end-effector’s pose in large operating spaces is the key for the mobile manipulator to realize efficient manufacturing of large and complex components.We propose a novel pose tracking method in large-range using visual fiducial markers,and further propose the layout optimization method for the encoded fiducial markers.A metric named orientational dilution of precision(ODOP)is proposed to evaluate the magnification of the pose estimation error compared with the measurement error of the coded fiducial markers.The distribution pattern of the coded markers is analyzed based on ODOP,and the square-shaped layout is determined to be a satisfactory distribution pattern for the minimum positioning unit of markers,and the side length of the square-shaped layout is further selected.The simulations and experiments prove the effectiveness of the ODOP index.Finally,the square-shaped layout and the designed distribution density for positioning coded markers are adopted to realize the high-precision measurement of large components by the mobile manipulator.展开更多
A collage is a composite artwork made from the spatial layout of multiple pictures on a canvas,collected from the Internet or user photographs.Collages,usually made by skilled artists,involve a complex manual process,...A collage is a composite artwork made from the spatial layout of multiple pictures on a canvas,collected from the Internet or user photographs.Collages,usually made by skilled artists,involve a complex manual process,especially when searching for component pictures and adjusting their spatial layout to meet artistic requirements.In this paper,we present a visual perception driven method for automatically synthesizing visually pleasing collages.Unlike previous works,we focus on how to design a collage layout which not only provides easy access to the theme of the overall image,but also conforms to human visual perception.To achieve this goal,we formulate the generation of collages as a mapping problem:given a canvas image,first,compute a saliency map for it and a vector field for each sub-region of it.Second,using a divide-and-conquer strategy,generate a series of patch sets from the canvas image,where the salient map and the vector field are used to determine each patch’s size and direction respectively.Third,construct a Gestalt-based energy function to choose the most visually pleasing and orderly patch set as the final layout.Finally,using a semantic-color metric,map the picture set to the patch set to generate the final collage.Extensive experimental and user study results show that this method can generate visual pleasing collages.展开更多
Structure Data Layout Optimization(SDLO)is a prevailing compiler optimization technique to improve cache efficiency.Structure transformation is a critical step for SDLO.Diversity of transformation methods and existenc...Structure Data Layout Optimization(SDLO)is a prevailing compiler optimization technique to improve cache efficiency.Structure transformation is a critical step for SDLO.Diversity of transformation methods and existence of complex data types are major challenges for structure transformation.We have designed and implemented STrans,a well-defined system which provides controllable and comprehensive functionality on structure transformation.Compared to known systems,it has less limitation on data types for transformation.In this paper we give formal definition of the approach STrans transforms data types.We have also designed Transformation Specification Language,a mini language to configure how to transform structures,which can be either manually tuned or generated by compiler.STrans supports three kinds of transformation methods,i.e.,splitting,peeling,and pool-splitting,and works well on different combinations of compound data types.STrans is the transformation system used in ASLOP and is well tested for all benchmarks for ASLOP.展开更多
This paper proposes an efficient PSP-based model for cross-coupled metal-oxide-semiconductor field-effect transistors(MOSFETs) with optimized layout in the voltage controlled oscillator(VCO).The model employs a PSP ch...This paper proposes an efficient PSP-based model for cross-coupled metal-oxide-semiconductor field-effect transistors(MOSFETs) with optimized layout in the voltage controlled oscillator(VCO).The model employs a PSP charge model to characterize the bias-dependent extrinsic capacitance instead of numerical functions with strong non-linearity.The simulation convergence is greatly improved by this method.An original scheme is developed to extract the parameters of the PSP charge model based on S-parameters measurement.The interconnection parasitics of the cross-coupled MOSFETs are modeled based on vector fitting.The model is verified with an LC VCO design,and exhibits excellent convergence during simulation.The results show improvements as high as 60.5% and 61.8% in simulation efficiency and accuracy,respectively,indicating that the proposed model better characterizes optimized cross-coupled MOSFETs in advanced radio frequency(RF) circuit design.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51777067).
文摘In feeder automation transformation there are difficulties in equipment and location selection.To help with this,an optimal layout model of feeder automation equipment oriented to the type of fault detection and local action is pro-posed.It analyzes the coordination relationship of the three most common types of automation equipment,i.e.,fault indicator,over-current trip switch and non-voltage trip switch in the fault handling process,and the explicit expres-sions of power outage time caused by a fault on different layouts of the above three types of equipment are given.Given constraints of power supply reliability and the goal of minimizing the sum of equipment-related capital invest-ment and power interruption cost,a mixed-integer quadratic programming model for optimal layout is established,in which the functional failure probability of equipment is linearized using the 3δprinciple in statistics.Finally,the basic characteristics of the proposed model are illustrated by different scenarios on the IEEE RBTS-BUS6 system.It can not only take into account fault location and fault isolation to enhance user power consumption perception,but also can guide precise investment to improve the operational quality and efficiency of a power company.
基金Supported by National Natural Science Foundation of China(Grant No.52005371)Shanghai Municipal Natural Science Foundation of China(Grant No.22ZR1463900)+1 种基金Fundamental Research Funds for the Central Universities of China(Grant No.22120220649)State Key Laboratory of Mechanical System and Vibration of China(Grant No.MSV202318).
文摘An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past decades.However,few papers systematically review these researches.By analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods applied.The process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout optimization.This paper makes a review of the fixture layout for thin-walled parts according to these three steps.First,two different kinds of optimization objectives are introduced.Researchers usually consider in-plane variations or out-of-plane deformations when designing objectives.Then,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based methods.Several common methods are discussed respectively.After that,optimization algorithms are reviewed systematically.There are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic algorithms.Finally,discussions on the current situation are provided.The research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization algorithms.Also,a new research point for fixture layout optimization is discussed.This paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.
基金supported by Aerospace Frontier Inspiration Project (Grant No.KY0505072113) from College of Aerospace Science and Engineering,NUDT,which are gratefully acknowledged by the authors.
文摘The spacecraequipment layout optimization design(SELOD)problems with complicated performance con-straints and diversity are studied in this paper.The previous literature uses the gradient-based algorithm to obtain optimized non-overlap layout schemes from randomly initialized cases eectively.However,these local optimal solutions are too dicult to jump out of their current relative geometry relationships,signicantly limiting their further improvement in performance indicators.Therefore,considering the geometric diversity of layout schemes is put forward to alleviate this limitation.First,similarity measures,including modied cosine similarity and gaussian kernel function similarity,are introduced into the layout optimization process.Then the optimization produces a set of feasible layout candidates with the most remarkable dierence in geometric distribution and the most representative schemes are sampled.Finally,these feasible geometric solutions are used as initial solutions to optimize the physical performance indicators of the spacecra,and diversied layout schemes of spacecraequipment are generated for the engineering practice.The validity and eectiveness of the proposed methodology are demonstrated by two SELOD applications.
基金partially supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI(JP22H03643)Japan Science and Technology Agency(JST)Support for Pioneering Research Initiated by the Next Generation(SPRING)(JPMJSP2145)JST through the Establishment of University Fellowships towards the Creation of Science Technology Innovation(JPMJFS2115)。
文摘Wind energy has been widely applied in power generation to alleviate climate problems.The wind turbine layout of a wind farm is a primary factor of impacting power conversion efficiency due to the wake effect that reduces the power outputs of wind turbines located in downstream.Wind farm layout optimization(WFLO)aims to reduce the wake effect for maximizing the power outputs of the wind farm.Nevertheless,the wake effect among wind turbines increases significantly as the number of wind turbines increases in the wind farm,which severely affect power conversion efficiency.Conventional heuristic algorithms suffer from issues of low solution quality and local optimum for large-scale WFLO under complex wind scenarios.Thus,a chaotic local search-based genetic learning particle swarm optimizer(CGPSO)is proposed to optimize large-scale WFLO problems.CGPSO is tested on four larger-scale wind farms under four complex wind scenarios and compares with eight state-of-the-art algorithms.The experiment results indicate that CGPSO significantly outperforms its competitors in terms of performance,stability,and robustness.To be specific,a success and failure memories-based selection is proposed to choose a chaotic map for chaotic search local.It improves the solution quality.The parameter and search pattern of chaotic local search are also analyzed for WFLO problems.
基金General Project of Humanities and Social Science Research of Ministry of Education,China(16YJC760073)Social Science Planning Project of Jiangxi Province(18YS07)+1 种基金Humanities and Social Science Research Project for Colleges and Universities in Jiangxi Province(YS1531)Innovation and Entrepreneurship Training Program for Undergraduates in Jiangxi Agricultural University(S202010410015).
文摘Urban park is one of the few green spaces that retain natural traces and are easy for the elderly to reach,and it has become the main place for the elderly to carry out leisure,entertainment,physical fi tness and interpersonal activities.The reasonable layout of urban parks is of great signifi cance to improve the quality of life of the elderly in old age.In this article,using the network analysis method in ArcGIS software,the accessibility of urban parks in Xihu District of Nanchang City based on elderly walking was evaluated and analyzed,and three strategies for optimizing the layout of the urban parks were proposed,including increasing the number of urban parks,improving the urban traffic network,and strengthening urban greenway planning and construction.The research results can provide reference for the optimal layout of urban parks in Xihu District,Nanchang City,so that the urban parks can better meet the outdoor leisure needs of the elderly,and the elderly’s sense of well-being and gain is enhanced.
文摘Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.
文摘This paper investigates the validity and shortcomings of the existing analytical solution for the ultimate bearing capacity of a pile embedded in a rock mass using the modified HoekeBrown failure criterion.Although this criterion is considered a reference value for empirical and numerical calculations,some limitations of its basic simplifications have not been clarified yet.This research compares the analytical results obtained from the novel discontinuity layout optimization(DLO)method and the numerical solutions from the finite difference method(FDM).The limitations of the analytical solution are considered by comparing different DLO failure modes,thus allowing for the first time a critical evaluation of its scope and conditioning for implementation.Errors of up to 40%in the bearing capacity and unrealistic failure modes are the main issues in the analytical solution.The main aspects of the DLO method are also analyzed with an emphasis on the linearization of the rock failure criterion and the accuracy resulting from the discretization size.The analysis demonstrates DLO as a very efficient and accurate tool to address the pile tip bearing capacity,presenting considerable advantages over other methods.
文摘A hot primary-air pipe system is the bridge connecting an air-preheater with a coal mill in power generation stations.The effective geometrical configuration of the pipe network greatly affects the air flow distribution and consequently influences the safe and economic operation of milling systems in power stations.In order to improve the properties of the air flow,in the present work the SIMPLEC method is used to simulate numerically the flow field for the original layout of the system.As a result,the internal mechanisms influencing the uneven pressure drop in each branch are explored and three optimization schemes are proposed accordingly.The numerical results indicate that,for the original layout,the local pressure drop of the tee section accounts for approximately 74%of the total drop of the system,with other pressure drops depending on the specific branch considered.It is shown that after optimization,a roughly balanced flow resistance and flow rate can be obtained.Compared with the original layout,the pressure drop relating to different branches is significantly reduced.
基金Natural Science Foundation of Hubei Province(No.2021CFB402)Key Laboratory of National Geographic Census and Monitoring,Ministry of Natural Resources(No.2020NGCMZD03)。
文摘The delimitation of urban development boundaries plays an important role in optimizing the nation land space.“Double evaluation”is one of the important means to study and predict the scale of new construction land in the future and to determine the spatial distribution of urban construction land.This study combines the“double evaluation”with the FLUS(Future Land-Use Simulation)model to study the delimitation of the urban development boundary of Yichang.The results show that:(1)the“double evaluation”method comprehensively considers the carrying capacity of the resource environmental bear and the suitability of urban development;(2)the FLUS model can better couple the“double evaluation”method for Land Use/Land Cover(LULC)suitability evaluation,Land Use/land Cover Change(LUCC)simulation and urban development boundary delineation,and the overall accuracy of the simulation reaches 96%;(3)according to the requirements of relevant national policies,this study divides the urban development boundary of the study area into concentrated construction areas,elastic development areas and special purpose areas.This function-based division can meet the requirements of urban flexible development,ecological protection and urban safety.This research combines the FLUS model,which is widely used in the simulation of LUCC,with the double evaluation method used in China’s new round of land and space planning to obtain the result of the urban development boundary.This result is consistent with the existing plan of the study area.
基金support of the Fundamen-tal Research Funds for the Central Universities(No.3072021CF0101)the‘Integration Software of Offshore Float-ing Platform Engineering Design(No.2016YFC0302900)’from the Ministry of Science and Technology of China,and the Project of Development of Floating Offshore Wind Turbine Risk Assessment Software Project,funded by the International S&T Cooperation Program of China(No.2013DFE73060).
文摘As the first step of the fire/gas-detection systems of floating production storage and offloading(FPSO)units is to iden-tify leakage accidents,gas detectors play an important role in controlling the leakage risk.To improve the leakage scenario detection rate and reduce the cumulative risk value,this paper presents an optimization method of the gas detector placement.The probability density distribution and cumulative probability density distribution of the leakage source variables and environmental variables were calculated based on the Offshore Reliability Data and the statistical data of the relevant leakage variables.A potential leakage sce-nario set was constructed using Latin hypercube sampling.The typical FPSO leakage scenarios were analyzed through computational fluid dynamics(CFD),and the impacts of different parameters on the leakage were addressed.A series of detectors was deployed according to the simulation results.The minimization of the product of effective detection time and gas leakage volume was the risk optimization objective,and the location and number of detectors were taken as decision variables.A greedy extraction heuristic algo-rithm was used to solve the optimization problem.The results show that the optimized placement had a better monitoring effect on the leakage scenario.
基金The authors gratefully acknowledge the financial support to this work from the National Natural Science Foundation of China(Grants 11802164 and U1808215)Shandong Provincial Natural Science Foundation(Grant ZR2019BEE005)the project funded by China Postdoctoral Science Foundation.
文摘Stiffened plates or shells are widely used in engineering structures as primary or secondary load-bearing components.How to design the layout and sizes of the stiffeners is of great significance for structural lightweight.In this work,a new topology optimization method for simultaneously optimizing the layout and cross-section topology of the stiffeners is developed to solve this issue.The stilfeners and base plates are modeled by the beam and shell elements,respectively,significantly reducing the computational cost.The Giavotto beam theory,instead of the widely employed Euler or Timoshenko beam theory,is applied to model the stiffeners for considering the warping deformation in evaluating the section stiffness of the beam.A multi-scale topology optimization model is established by simultaneously optimizing the layout of the beam and the topology of the cross-section.The design space is significantly expanded by optimizing these two types of design variables.Several numerical examples are applied to illustrate the validity and effectiveness of the proposed method.The results show that the proposed two-scale optimization approach can generate better designs than the single-scale method.
文摘This paper presents a developed meta-heuristic algorithm to optimize the shear walls of tall reinforced concrete buildings.These types of walls are considered as lateral resistant elements.In this paper,Quantum Charged System Search(QCSS)algorithm is presented as a new optimization method and used to improve the convergence capability of the original Charged System Search.The cost of tall building is taken as the objective function.Since the design of the lateral system plays a major role in the performance of the tall buildings,this paper proposes a unique computational technique that,unlike available works,focuses on structural efficiency or architectural design.This technique considers both structural and architectural requirements such as minimum structural costs,torsional effects,flexural and shear resistance,lateral deflection,openings and accessibility.The robustness of the new algorithm is demonstrated by comparing the outcomes of the QCSS with those of its standard algorithm.
基金supported by the National Natural Science Foundation of China(No.51377178,51607051)Anhui Provincial Natural Science Foundation(No.1908085QE237,2108085UD08)Visiting Scholarship of State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University)(2007DA105127).
文摘The fluctuation of wind power brings great challenges to the secure,stable,and cost-efficient operation of the power system.Because of the time-correlation of wind speed and the wake effect of wind turbines,the layout of wind farm has a significant impact on the wind power sequential fluctuation.In order to reduce the fluctuation of wind power and improve the operation security with lower operating cost,a bi-objective layout optimization model for multiple wind farms considering the sequential fluctuation of wind power is proposed in this paper.The goal is to determine the optimal installed capacity of wind farms and the location of wind turbines.The proposed model maximizes the energy production and minimizes the fluctuation of wind power simultaneously.To improve the accuracy of wind speed estimation and hence the power calculation,the timeshifting of wind speed between the wind tower and turbines’locations is also considered.A uniform design based two-stage genetic algorithm is developed for the solution of the proposed model.Case studies demonstrate the effectiveness of this proposed model.
基金supported by the Project of the Institute for State-Owned Enterprises,Tsinghua University(Research on the Improvement of State-Owned Capital Distribution based on the perspective of the State Capital Investing and Operating Company,No.iSOEYB202212)the Key Project of the National Natural Science Foundation of China(No.71790603)
文摘This paper explores the influence of the State Capital Investing and Operating Company(SCIOC)pilot reform on SOE bailout using a staggered differencein-differences model.Based on a sample of listed SOEs during 2011-2018,we find that when the real controllers of listed SOEs enter the list of SCIOCs,soft budget constraints are alleviated and listed subsidiaries are less likely to become distressed.Mechanism tests indicate that SCIOCs help distressed firms through exiting the market,reducing bank loans,enhancing corporate governance,and improving operating efficiency.Heterogeneity tests show that the effect of SCIOC establishment is more significant in central and western regions,in public welfare and special function industries,for central SCIOCs,for state capital investing companies,when firms are organized in more layers,and for firms that engage in M&As.The empirical results show that the implementation of SCIOCs benefits both micro-enterprise development and state capital layout optimization.
基金supported by National Natural Science Foundation of China (Nos. 11802243 and 11902258)Natural Science Foundation of Shaanxi Province (No. 2019JQ-176)+1 种基金Key Project of NSFC (Nos. 51790171, 51761145111 and 51735005)NSFC for Excellent Young Scholars (No. 11722219)。
文摘Smart morphing wing, which is equipped with smart materials and able to change structural geometry adaptively, can further improve aerodynamic efficiency of aircraft. This paper presents a new integrated layout and topology optimization design for morphing wing driven by shape memory alloys(SMAs). By simultaneously optimizing the layout of smart actuators and topology of wing substrate, the ultimately determined configuration can achieve smooth, continuous and accurate geometric shape changes. In addition, aerodynamic analysis is carried out to compare smart morphing wing with traditional hinged airfoil. Finally, the optimized smart wing structure is constructed and tested to demonstrate and verify the morphing functionality. Application setbacks are also pointed out for further investigation.
文摘Climate change within the urban contexts is a crisis that cities are confronting globally.This issue poses numerous negative consequences such as thermal discomfort and increased energy usage within the building sector.This is especially the case in Western Sydney,Australia,where the average maximum temperature has risen by 7—8℃ within the past 30 years.This increase in temperature is highly concerning,since this region is witnessing rapid urban and infrastructural development and is proposed as the third-largest economy of Australia.Temperature changes in this region will also result in considerably increasing the electricity used for cooling purposes.This paper presents a parametric approach driven multi-objective optimization methodology to discover optimum design solution based on the urban microclimate and cooling energy demand of multi-functional buildings within this urban context.Mitigation measures including a range of design factors at both building(typology and window to wall ratio)and urban scales(aspect ratio and urban grid rotation)are further suggested for developing context sensitive optimum urban layouts.The resultant solutions indicate an improvement in urban thermal comfort,cooling and heating energy use by up to 25.85%,72.76%,and 93.67%,respectively.
基金supported in part by the National Key Research and Development Program of China(Grant No.2017YFB1301504)the National Natural Science Foundation of China(Grant Nos.91748204,91948301 and 51905183)the China Postdoctoral Science Foundation(Grant No.2018M642820).
文摘The accurate estimation of the end-effector’s pose in large operating spaces is the key for the mobile manipulator to realize efficient manufacturing of large and complex components.We propose a novel pose tracking method in large-range using visual fiducial markers,and further propose the layout optimization method for the encoded fiducial markers.A metric named orientational dilution of precision(ODOP)is proposed to evaluate the magnification of the pose estimation error compared with the measurement error of the coded fiducial markers.The distribution pattern of the coded markers is analyzed based on ODOP,and the square-shaped layout is determined to be a satisfactory distribution pattern for the minimum positioning unit of markers,and the side length of the square-shaped layout is further selected.The simulations and experiments prove the effectiveness of the ODOP index.Finally,the square-shaped layout and the designed distribution density for positioning coded markers are adopted to realize the high-precision measurement of large components by the mobile manipulator.
基金supported by the National Natural Science Foundation of China(No.61772440)the Aeronautical Science Foundation of China(No.20165168007)Science and Technology of Electrooptic Control Laboratory.
文摘A collage is a composite artwork made from the spatial layout of multiple pictures on a canvas,collected from the Internet or user photographs.Collages,usually made by skilled artists,involve a complex manual process,especially when searching for component pictures and adjusting their spatial layout to meet artistic requirements.In this paper,we present a visual perception driven method for automatically synthesizing visually pleasing collages.Unlike previous works,we focus on how to design a collage layout which not only provides easy access to the theme of the overall image,but also conforms to human visual perception.To achieve this goal,we formulate the generation of collages as a mapping problem:given a canvas image,first,compute a saliency map for it and a vector field for each sub-region of it.Second,using a divide-and-conquer strategy,generate a series of patch sets from the canvas image,where the salient map and the vector field are used to determine each patch’s size and direction respectively.Third,construct a Gestalt-based energy function to choose the most visually pleasing and orderly patch set as the final layout.Finally,using a semantic-color metric,map the picture set to the patch set to generate the final collage.Extensive experimental and user study results show that this method can generate visual pleasing collages.
基金supported by the National Natural Science Foundation of China(No.61133006)the National High-Tech Research and Development(863)Program of China(No.2012AA010901)
文摘Structure Data Layout Optimization(SDLO)is a prevailing compiler optimization technique to improve cache efficiency.Structure transformation is a critical step for SDLO.Diversity of transformation methods and existence of complex data types are major challenges for structure transformation.We have designed and implemented STrans,a well-defined system which provides controllable and comprehensive functionality on structure transformation.Compared to known systems,it has less limitation on data types for transformation.In this paper we give formal definition of the approach STrans transforms data types.We have also designed Transformation Specification Language,a mini language to configure how to transform structures,which can be either manually tuned or generated by compiler.STrans supports three kinds of transformation methods,i.e.,splitting,peeling,and pool-splitting,and works well on different combinations of compound data types.STrans is the transformation system used in ASLOP and is well tested for all benchmarks for ASLOP.
基金Project supported by the National Basic Research Program (973) of China (No. 2010CB327403)the National Natural Science Foundation of China (Nos. 61001066 and 61102027)
文摘This paper proposes an efficient PSP-based model for cross-coupled metal-oxide-semiconductor field-effect transistors(MOSFETs) with optimized layout in the voltage controlled oscillator(VCO).The model employs a PSP charge model to characterize the bias-dependent extrinsic capacitance instead of numerical functions with strong non-linearity.The simulation convergence is greatly improved by this method.An original scheme is developed to extract the parameters of the PSP charge model based on S-parameters measurement.The interconnection parasitics of the cross-coupled MOSFETs are modeled based on vector fitting.The model is verified with an LC VCO design,and exhibits excellent convergence during simulation.The results show improvements as high as 60.5% and 61.8% in simulation efficiency and accuracy,respectively,indicating that the proposed model better characterizes optimized cross-coupled MOSFETs in advanced radio frequency(RF) circuit design.
