In this paper,the geological condition of the right-side slope of the K114+694–K115+162 section of Yong-tai-wen Expressway is investigated and analyzed with the results showing that the strength of rock mass is the m...In this paper,the geological condition of the right-side slope of the K114+694–K115+162 section of Yong-tai-wen Expressway is investigated and analyzed with the results showing that the strength of rock mass is the main contributor to the stability of the slope.Then,two widening schemes are proposed,which are the steep slope with strong support and the gentle slope with general support schemes.The static/slope module of MIDAS GTS finite element analysis software and the strength reduction method were used to compare the two schemes.The results show that the steep slope with a strong support scheme has obvious advantages in land requisition,environmental protection,and safety and is more suitable for reconstructing and expanding the highway slope.展开更多
[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Meth...[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Methods]With the progeny of the white birch populations naturally distributed in northern China as objects,based on genetic effect analysis and comprehensive evaluation,the genetic variation,heritability and genetic gain of the growth characters in the progeny forest were systematically analyzed,by which populations or individuals with good growth vigor and strong stress resistance and adaptability were finally selected.[Results]There were extremely significant differences in the growth characters between the natural populations of white birch in northern China.The variation was the smallest in tree height,followed by crown width,and largest in DBH,and the average coefficients of variation were 20.56%,32.25%and 33.00%,respectively.The differences in characters between progeny of the same population were also extremely significant.The growth characters of white birch were more controlled by genes,and the genetic gains were larger.The heritability of tree height,DBH and crown width was 0.971,0.816 and 0.576,respectively,and the genetic gains were 15.97%,21.54%and 13.87%,respectively.[Conclusions]With the growth characters as the main evaluation indexes,taking various influencing factors into account,the Shanxi[SX]population,Hebei[HB]population and Liaoning[LN]population were selected to be excellent populations,and LN305,SX516 and HB403 were excellent individuals,which are advised to be widely used in multi-generation genetic improvement breeding.展开更多
The technological scheme of a hard rock surface mine is a multiple level production system of interdependently func-tioning elements. Selection of the optimum combination of its elements constitutes a complex multiple...The technological scheme of a hard rock surface mine is a multiple level production system of interdependently func-tioning elements. Selection of the optimum combination of its elements constitutes a complex multiple variant and criteria problem of decision making. In this paper describes the theoretical part of the method proposed for the quantitative analysis and selection of the most competent technological schemes, based on the mathematical formulations of the selection criteria of the element of each level as functions of the alternative variants of the elements of the level and its adjacent levels. It is realized in accordance to standard procedures of decision making in the formation of the economical mathematical model of the cumulative influence of levels and elements on the effectiveness of all alternative variants in their analysis and generation of a small subset of the most competent variants, which are subjected to further analysis using the criterion of reliability in the generation of the optimum technological scheme. The scientific challenge inherent in its realization constitutes a PhD research opportunity for those interested in the problems of optimization in hard rock surface mines.展开更多
Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level ...Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level and the mechanism level of conceptual design.The principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters.Then on the basis of mentioned above,the heuristic matching propagation principle (HMPP) of kinematic behaviors and its true table serves as a guide to perform mechanism types selection.Finally an application is given to indicate its practicability and effectiveness.展开更多
The development of new robot structures, in particular of parallel kinematic machines(PKM), is widely systematized by different structure synthesis methods. Recent research increasingly focuses on PKM with less than...The development of new robot structures, in particular of parallel kinematic machines(PKM), is widely systematized by different structure synthesis methods. Recent research increasingly focuses on PKM with less than six degrees of freedom(DOF). However, an overall comparison and evaluation of these structures is missing. In order to compare symmetrical PKM with three translational DOF, different evaluation criteria are used. Workspace, maximum actuation forces and velocities, power, actuator stiffness, accuracy and transmission behavior are taken into account to investigate strengths and weaknesses of the PKMs. A selection scheme based on possible configurations of translational PKM including different frame configurations is presented. Moreover, an optimization method based on a genetic algorithm is described to determine the geometric parameters of the selected PKM for an exemplary load case and a prescribed workspace. The values of the mentioned criteria are determined for all considered PKM with respect to certain boundary conditions. The distribution and spreading of these values within the prescribed workspace is presented by using box plots for each criterion. Thereby, the performance characteristics of the different structures can be compared directly. The results show that there is no "best" PKM. Further inquiries such as dynamic or stiffness analysis are necessary to extend the comparison and to finally select a PKM.展开更多
Genomic selection is more and more popular in animal and plant breeding industries all around the world, as it can be applied early in life without impacting selection candidates. The objective of this study was to br...Genomic selection is more and more popular in animal and plant breeding industries all around the world, as it can be applied early in life without impacting selection candidates. The objective of this study was to bring the advantages of genomic selection to scallop breeding. Two different genomic selection tools Mix P and gsbay were applied on genomic evaluation of simulated data and Zhikong scallop(Chlamys farreri) field data. The data were compared with genomic best linear unbiased prediction(GBLUP) method which has been applied widely. Our results showed that both Mix P and gsbay could accurately estimate single-nucleotide polymorphism(SNP) marker effects, and thereby could be applied for the analysis of genomic estimated breeding values(GEBV). In simulated data from different scenarios, the accuracy of GEBV acquired was ranged from 0.20 to 0.78 by Mix P; it was ranged from 0.21 to 0.67 by gsbay; and it was ranged from 0.21 to 0.61 by GBLUP. Estimations made by Mix P and gsbay were expected to be more reliable than those estimated by GBLUP. Predictions made by gsbay were more robust, while with Mix P the computation is much faster, especially in dealing with large-scale data. These results suggested that both algorithms implemented by Mix P and gsbay are feasible to carry out genomic selection in scallop breeding, and more genotype data will be necessary to produce genomic estimated breeding values with a higher accuracy for the industry.展开更多
China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction...China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction and expansion project of the Yinkun Expressway's Chongqing High-tech Zone to Rongchang District section,with a detailed exploration of the entire design process.Through a comprehensive analysis,the strengths and weaknesses of different plans are examined,so as to determine the optimal plan.The design chosen saves costs while effectively addressing traffic demands.Additionally,the study summarizes the valuable design insights gained from this interchange transformation,aiming to provide valuable reference for similar interchange projects in the future.展开更多
A new approach for selecting proper discretization schemes and grid size is presented. This method is based on the convection-diffusion equation and can provide insight for the Navier-Stokes equation. The approach mai...A new approach for selecting proper discretization schemes and grid size is presented. This method is based on the convection-diffusion equation and can provide insight for the Navier-Stokes equation. The approach mainly addresses two aspects, i.e., the practical accuracy of diffusion term discretization and the behavior of high wavenum- ber disturbances. Two criteria are included in this approach. First, numerical diffusion should not affect the theoretical diffusion accuracy near the length scales of interest. This is achieved by requiring numerical diffusion to be smaller than the diffusion discretization error. Second, high wavenumber modes that are.much smaller than the length scales of interest should not be amplified. These two criteria provide a range of suitable scheme combinations for convective flux and diffusive flux and an ideal interval for grid spacing. The effects of time discretization on these criteria are briefly discussed.展开更多
As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable...As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable homes.Taking the urban water system of Nantong as an example,Nantong Water Resources Bureau issued R evision of Nantong Urban Water System Planning in 2017,and put forward the construction of the"two circles,eight lakes and nine veins"water system layout,giving new vitality to the urban water system.In view of problems existing in newly excavated artificial landscape lakes,such as fragile water ecosystem,strong eutrophication trend,poor environmental sensory effect and unsatisfactory water landscape effect,it is urgent to study the in-situ water ecological restoration technique of"algae-controlling zooplankton+submerged plant community"to build a"grass-type clear water"ecosystem for artificial landscape lakes,so as to improve the water sensory index and self-purification ability and finally realize the double improvement of"sensory effect and water quality"of artificial landscape lakes.展开更多
In order to support advanced vehicular Internet-of-Things(IoT)applications,information exchanges among different vehicles are required to find efficient solutions for catering to different application requirements in ...In order to support advanced vehicular Internet-of-Things(IoT)applications,information exchanges among different vehicles are required to find efficient solutions for catering to different application requirements in complex and dynamic vehicular environments.Federated learning(FL),which is a type of distributed learning technology,has been attracting great interest in recent years as it performs knowledge exchange among different network entities without a violation of user privacy.However,client selection and networking scheme for enabling FL in dynamic vehicular environments,which determines the communication delay between FL clients and the central server that aggregates the models received from the clients,is still under-explored.In this paper,we propose an edge computing-based joint client selection and networking scheme for vehicular IoT.The proposed scheme assigns some vehicles as edge vehicles by employing a distributed approach,and uses the edge vehicles as FL clients to conduct the training of local models,which learns optimal behaviors based on the interaction with environments.The clients also work as forwarder nodes in information sharing among network entities.The client selection takes into account the vehicle velocity,vehicle distribution,and the wireless link connectivity between vehicles using a fuzzy logic algorithm,resulting in an efficient learning and networking architecture.We use computer simulations to evaluate the proposed scheme in terms of the communication overhead and the information covered in learning.展开更多
Decomposition of tasks and selection of optimal schemes are key procedures in high-end equipment development processes.However,such procedures are highly innovative,technology intensive,interdisciplinary,and multi-par...Decomposition of tasks and selection of optimal schemes are key procedures in high-end equipment development processes.However,such procedures are highly innovative,technology intensive,interdisciplinary,and multi-party engineering projects,making the decomposition and scheme selection more difficult and complicated than that in the development of ordinary equipment.In this study,we consider three factors,namely,functional structure,task granularity,and task feasibility in task decomposition of high-end equipment development.Based on the principles of systems engineering,a method of task decomposition is proposed.As for decomposition scheme selection,a method based on the superiority and inferiority ranking(SIR)method mixed information and multiple attribute decision making is proposed by considering attributes of scheme feasibility,uncertainty risk and task integration complexity.To verify the proposed method,development of a military electric vehicle is used as an example to demonstrate the calculation process.展开更多
Distributed generation (DG) is the future of energy. This technology allows the bidirectional flow of power within an electrical network. Researchers are faced with many challenges to the accurate implementation of pr...Distributed generation (DG) is the future of energy. This technology allows the bidirectional flow of power within an electrical network. Researchers are faced with many challenges to the accurate implementation of protection schemes for DG-connected distribution network. The schemes designed must satisfy the performance requirements of selectivity, reliability, and sensitivity. Most researchers opine that conventional protection schemes based on over current detection are insufficient to completely and accurately protect a DG-connected distributed power system. There are many challenges?that?need to be tackled before embarking upon the journey to successfully implement these schemes. This paper summarizes the major challenges which one can encounter while designing protection schemes for DG-connected distribution networks. Some possible solutions from the literature are also mentioned. Moreover, a suggested solution for protecting future active distribution networks is provided. It is expected that this paper will act as a benchmark for future researchers in this field to tackle the challenges related to the protection of active distribution networks.展开更多
In order to research the capacity differences of road intersections,this paper analyzed the influence factors and calculation models of various types of capacity at intersections and then obtained simplified models th...In order to research the capacity differences of road intersections,this paper analyzed the influence factors and calculation models of various types of capacity at intersections and then obtained simplified models through reasonable assumption. 2 /2,4 /2,4 /4 intersections at which saturation and forecasted traffic volume were given were taken as examples,and an appropriate type was selected through capacity comparison. This paper can give a predictive estimation of the intersection capacity and provides theoretical data for the type selection of intersections.展开更多
Selecting the optimal one from similar schemes is a paramount work in equipment design.In consideration of similarity of schemes and repetition of characteristic indices,the theory of set pair analysis(SPA)is proposed...Selecting the optimal one from similar schemes is a paramount work in equipment design.In consideration of similarity of schemes and repetition of characteristic indices,the theory of set pair analysis(SPA)is proposed,and then an optimal selection model is established.In order to improve the accuracy and flexibility,the model is modified by the contribution degree.At last,this model has been validated by an example,and the result demonstrates the method is feasible and valuable for practical usage.展开更多
The optimal selection of schemes of water transportation projects is a process of choosing a relatively optimal scheme from a number of schemes of water transportation programming and management projects, which is of ...The optimal selection of schemes of water transportation projects is a process of choosing a relatively optimal scheme from a number of schemes of water transportation programming and management projects, which is of importance in both theory and practice in water resource systems engineering. In order to achieve consistency and eliminate the dimensions of fuzzy qualitative and fuzzy quantitative evaluation indexes, to determine the weights of the indexes objectively, and to increase the differences among the comprehensive evaluation index values of water transportation project schemes, a projection pursuit method, named FPRM-PP for short, was developed in this work for selecting the optimal water transportation project scheme based on the fuzzy preference relation matrix. The research results show that FPRM-PP is intuitive and practical, the correction range of the fuzzy preference relation matrix [WTHX]A[WT] it produces is relatively small, and the result obtained is both stable and accurate; therefore FPRM-PP can be widely used in the optimal selection of different multi-factor decision-making schemes.展开更多
According to traditional card problem solving which is based on the idea of genetic algorithm(GA),a set of algorithms is designed to find final solution.For each process in genetic algorithm,including choices of fitne...According to traditional card problem solving which is based on the idea of genetic algorithm(GA),a set of algorithms is designed to find final solution.For each process in genetic algorithm,including choices of fitness function,parameters determination and coding scheme selection,classic algorithm is used to realize the various steps,and ultimately to find solution of problems.展开更多
文摘In this paper,the geological condition of the right-side slope of the K114+694–K115+162 section of Yong-tai-wen Expressway is investigated and analyzed with the results showing that the strength of rock mass is the main contributor to the stability of the slope.Then,two widening schemes are proposed,which are the steep slope with strong support and the gentle slope with general support schemes.The static/slope module of MIDAS GTS finite element analysis software and the strength reduction method were used to compare the two schemes.The results show that the steep slope with a strong support scheme has obvious advantages in land requisition,environmental protection,and safety and is more suitable for reconstructing and expanding the highway slope.
基金Supported by Heilongjiang Provincial Science and Technology Department Project(GC04B116)National Forest Tree Germplasm Resource Platform Running Service Project(2011DKA21003-02)National Forestry Public Welfare Industry Research Project(201204307-07)
文摘[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Methods]With the progeny of the white birch populations naturally distributed in northern China as objects,based on genetic effect analysis and comprehensive evaluation,the genetic variation,heritability and genetic gain of the growth characters in the progeny forest were systematically analyzed,by which populations or individuals with good growth vigor and strong stress resistance and adaptability were finally selected.[Results]There were extremely significant differences in the growth characters between the natural populations of white birch in northern China.The variation was the smallest in tree height,followed by crown width,and largest in DBH,and the average coefficients of variation were 20.56%,32.25%and 33.00%,respectively.The differences in characters between progeny of the same population were also extremely significant.The growth characters of white birch were more controlled by genes,and the genetic gains were larger.The heritability of tree height,DBH and crown width was 0.971,0.816 and 0.576,respectively,and the genetic gains were 15.97%,21.54%and 13.87%,respectively.[Conclusions]With the growth characters as the main evaluation indexes,taking various influencing factors into account,the Shanxi[SX]population,Hebei[HB]population and Liaoning[LN]population were selected to be excellent populations,and LN305,SX516 and HB403 were excellent individuals,which are advised to be widely used in multi-generation genetic improvement breeding.
文摘The technological scheme of a hard rock surface mine is a multiple level production system of interdependently func-tioning elements. Selection of the optimum combination of its elements constitutes a complex multiple variant and criteria problem of decision making. In this paper describes the theoretical part of the method proposed for the quantitative analysis and selection of the most competent technological schemes, based on the mathematical formulations of the selection criteria of the element of each level as functions of the alternative variants of the elements of the level and its adjacent levels. It is realized in accordance to standard procedures of decision making in the formation of the economical mathematical model of the cumulative influence of levels and elements on the effectiveness of all alternative variants in their analysis and generation of a small subset of the most competent variants, which are subjected to further analysis using the criterion of reliability in the generation of the optimum technological scheme. The scientific challenge inherent in its realization constitutes a PhD research opportunity for those interested in the problems of optimization in hard rock surface mines.
基金Sponsored by the Chinese National Foundation of Science Na 59875058.
文摘Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level and the mechanism level of conceptual design.The principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters.Then on the basis of mentioned above,the heuristic matching propagation principle (HMPP) of kinematic behaviors and its true table serves as a guide to perform mechanism types selection.Finally an application is given to indicate its practicability and effectiveness.
文摘The development of new robot structures, in particular of parallel kinematic machines(PKM), is widely systematized by different structure synthesis methods. Recent research increasingly focuses on PKM with less than six degrees of freedom(DOF). However, an overall comparison and evaluation of these structures is missing. In order to compare symmetrical PKM with three translational DOF, different evaluation criteria are used. Workspace, maximum actuation forces and velocities, power, actuator stiffness, accuracy and transmission behavior are taken into account to investigate strengths and weaknesses of the PKMs. A selection scheme based on possible configurations of translational PKM including different frame configurations is presented. Moreover, an optimization method based on a genetic algorithm is described to determine the geometric parameters of the selected PKM for an exemplary load case and a prescribed workspace. The values of the mentioned criteria are determined for all considered PKM with respect to certain boundary conditions. The distribution and spreading of these values within the prescribed workspace is presented by using box plots for each criterion. Thereby, the performance characteristics of the different structures can be compared directly. The results show that there is no "best" PKM. Further inquiries such as dynamic or stiffness analysis are necessary to extend the comparison and to finally select a PKM.
基金supported by the National High-Tech R&D Program (863 Program No. 2012AA10A405)the earmarked fund for Modern Agro-industry Technology Research Systemthe National Natural Science Foundation of China (No. 31302182)
文摘Genomic selection is more and more popular in animal and plant breeding industries all around the world, as it can be applied early in life without impacting selection candidates. The objective of this study was to bring the advantages of genomic selection to scallop breeding. Two different genomic selection tools Mix P and gsbay were applied on genomic evaluation of simulated data and Zhikong scallop(Chlamys farreri) field data. The data were compared with genomic best linear unbiased prediction(GBLUP) method which has been applied widely. Our results showed that both Mix P and gsbay could accurately estimate single-nucleotide polymorphism(SNP) marker effects, and thereby could be applied for the analysis of genomic estimated breeding values(GEBV). In simulated data from different scenarios, the accuracy of GEBV acquired was ranged from 0.20 to 0.78 by Mix P; it was ranged from 0.21 to 0.67 by gsbay; and it was ranged from 0.21 to 0.61 by GBLUP. Estimations made by Mix P and gsbay were expected to be more reliable than those estimated by GBLUP. Predictions made by gsbay were more robust, while with Mix P the computation is much faster, especially in dealing with large-scale data. These results suggested that both algorithms implemented by Mix P and gsbay are feasible to carry out genomic selection in scallop breeding, and more genotype data will be necessary to produce genomic estimated breeding values with a higher accuracy for the industry.
文摘China's road network consists of numerous older expressways experiencing high traffic volumes and severe congestion,necessitating urgent reconstruction and expansion efforts.This study discusses the reconstruction and expansion project of the Yinkun Expressway's Chongqing High-tech Zone to Rongchang District section,with a detailed exploration of the entire design process.Through a comprehensive analysis,the strengths and weaknesses of different plans are examined,so as to determine the optimal plan.The design chosen saves costs while effectively addressing traffic demands.Additionally,the study summarizes the valuable design insights gained from this interchange transformation,aiming to provide valuable reference for similar interchange projects in the future.
基金Project supported by the National Natural Science Foundation of China(No.11372254)
文摘A new approach for selecting proper discretization schemes and grid size is presented. This method is based on the convection-diffusion equation and can provide insight for the Navier-Stokes equation. The approach mainly addresses two aspects, i.e., the practical accuracy of diffusion term discretization and the behavior of high wavenum- ber disturbances. Two criteria are included in this approach. First, numerical diffusion should not affect the theoretical diffusion accuracy near the length scales of interest. This is achieved by requiring numerical diffusion to be smaller than the diffusion discretization error. Second, high wavenumber modes that are.much smaller than the length scales of interest should not be amplified. These two criteria provide a range of suitable scheme combinations for convective flux and diffusive flux and an ideal interval for grid spacing. The effects of time discretization on these criteria are briefly discussed.
基金Supported by Jiangsu Province Engineering Research Center of Agricultural and Rural Pollution Prevention Technology and Equipment(Sufagaigaojifa[2022]No.1103)Innovation and Entrepreneurship Incubation Program for Students in Vocational Colleges of Jiangsu Province in 2023(G-2023-1257)+3 种基金High-end Training Program for Teachers Professional Leaders in Higher Vocational Colleges of Jiangsu Province in 2023(Sugaozhipeihan[2023]No.9)General Project of Philosophy and Social Science Research in Colleges and Universities of Jiangsu Province in 2023(2023SJYB1785)Project of Nantong Science and Technology Bureau(MSZ2022176MS22022120).
文摘As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable homes.Taking the urban water system of Nantong as an example,Nantong Water Resources Bureau issued R evision of Nantong Urban Water System Planning in 2017,and put forward the construction of the"two circles,eight lakes and nine veins"water system layout,giving new vitality to the urban water system.In view of problems existing in newly excavated artificial landscape lakes,such as fragile water ecosystem,strong eutrophication trend,poor environmental sensory effect and unsatisfactory water landscape effect,it is urgent to study the in-situ water ecological restoration technique of"algae-controlling zooplankton+submerged plant community"to build a"grass-type clear water"ecosystem for artificial landscape lakes,so as to improve the water sensory index and self-purification ability and finally realize the double improvement of"sensory effect and water quality"of artificial landscape lakes.
基金This research was supported in part by the National Natural Science Foundation of China under Grant No.62062031 and 61877053in part by Inner Mongolia natural science foundation grant number 2019MS06035,and Inner Mongolia Science and Technology Major Project,China+1 种基金in part by ROIS NII Open Collaborative Research 21S0601in part by JSPS KAKENHI grant numbers 18KK0279,19H04093,20H00592,and 21H03424.
文摘In order to support advanced vehicular Internet-of-Things(IoT)applications,information exchanges among different vehicles are required to find efficient solutions for catering to different application requirements in complex and dynamic vehicular environments.Federated learning(FL),which is a type of distributed learning technology,has been attracting great interest in recent years as it performs knowledge exchange among different network entities without a violation of user privacy.However,client selection and networking scheme for enabling FL in dynamic vehicular environments,which determines the communication delay between FL clients and the central server that aggregates the models received from the clients,is still under-explored.In this paper,we propose an edge computing-based joint client selection and networking scheme for vehicular IoT.The proposed scheme assigns some vehicles as edge vehicles by employing a distributed approach,and uses the edge vehicles as FL clients to conduct the training of local models,which learns optimal behaviors based on the interaction with environments.The clients also work as forwarder nodes in information sharing among network entities.The client selection takes into account the vehicle velocity,vehicle distribution,and the wireless link connectivity between vehicles using a fuzzy logic algorithm,resulting in an efficient learning and networking architecture.We use computer simulations to evaluate the proposed scheme in terms of the communication overhead and the information covered in learning.
基金supported by the National Natural Science Foundation of China(7169023371901214)the National Key R&D Program of China(2017YFC1405005)。
文摘Decomposition of tasks and selection of optimal schemes are key procedures in high-end equipment development processes.However,such procedures are highly innovative,technology intensive,interdisciplinary,and multi-party engineering projects,making the decomposition and scheme selection more difficult and complicated than that in the development of ordinary equipment.In this study,we consider three factors,namely,functional structure,task granularity,and task feasibility in task decomposition of high-end equipment development.Based on the principles of systems engineering,a method of task decomposition is proposed.As for decomposition scheme selection,a method based on the superiority and inferiority ranking(SIR)method mixed information and multiple attribute decision making is proposed by considering attributes of scheme feasibility,uncertainty risk and task integration complexity.To verify the proposed method,development of a military electric vehicle is used as an example to demonstrate the calculation process.
文摘Distributed generation (DG) is the future of energy. This technology allows the bidirectional flow of power within an electrical network. Researchers are faced with many challenges to the accurate implementation of protection schemes for DG-connected distribution network. The schemes designed must satisfy the performance requirements of selectivity, reliability, and sensitivity. Most researchers opine that conventional protection schemes based on over current detection are insufficient to completely and accurately protect a DG-connected distributed power system. There are many challenges?that?need to be tackled before embarking upon the journey to successfully implement these schemes. This paper summarizes the major challenges which one can encounter while designing protection schemes for DG-connected distribution networks. Some possible solutions from the literature are also mentioned. Moreover, a suggested solution for protecting future active distribution networks is provided. It is expected that this paper will act as a benchmark for future researchers in this field to tackle the challenges related to the protection of active distribution networks.
基金Sponsored by the Natural Science Foundation of Heilongjiang Province ( Grant No. E2007-14)
文摘In order to research the capacity differences of road intersections,this paper analyzed the influence factors and calculation models of various types of capacity at intersections and then obtained simplified models through reasonable assumption. 2 /2,4 /2,4 /4 intersections at which saturation and forecasted traffic volume were given were taken as examples,and an appropriate type was selected through capacity comparison. This paper can give a predictive estimation of the intersection capacity and provides theoretical data for the type selection of intersections.
文摘Selecting the optimal one from similar schemes is a paramount work in equipment design.In consideration of similarity of schemes and repetition of characteristic indices,the theory of set pair analysis(SPA)is proposed,and then an optimal selection model is established.In order to improve the accuracy and flexibility,the model is modified by the contribution degree.At last,this model has been validated by an example,and the result demonstrates the method is feasible and valuable for practical usage.
基金The authors would like to acknowledge the funding support of the National Natural Science Foundation of China (Nos. 50579009, 70425001 ) the National 10th Five Year Scientific Project of China for Tackling the Key Problems (2004BA608B-02-02)the Excellence Youth Teacher Sustentation Fund Program of the Ministry of Education of China (Department of Education and Personnel [ 2002 ] 350).
文摘The optimal selection of schemes of water transportation projects is a process of choosing a relatively optimal scheme from a number of schemes of water transportation programming and management projects, which is of importance in both theory and practice in water resource systems engineering. In order to achieve consistency and eliminate the dimensions of fuzzy qualitative and fuzzy quantitative evaluation indexes, to determine the weights of the indexes objectively, and to increase the differences among the comprehensive evaluation index values of water transportation project schemes, a projection pursuit method, named FPRM-PP for short, was developed in this work for selecting the optimal water transportation project scheme based on the fuzzy preference relation matrix. The research results show that FPRM-PP is intuitive and practical, the correction range of the fuzzy preference relation matrix [WTHX]A[WT] it produces is relatively small, and the result obtained is both stable and accurate; therefore FPRM-PP can be widely used in the optimal selection of different multi-factor decision-making schemes.
文摘According to traditional card problem solving which is based on the idea of genetic algorithm(GA),a set of algorithms is designed to find final solution.For each process in genetic algorithm,including choices of fitness function,parameters determination and coding scheme selection,classic algorithm is used to realize the various steps,and ultimately to find solution of problems.