Computation-based approaches in design have emerged in the last decades and rapidly became popular among architects and other designers.Design professionals and researchers adopted different terminologies to address t...Computation-based approaches in design have emerged in the last decades and rapidly became popular among architects and other designers.Design professionals and researchers adopted different terminologies to address these approaches.However,some terms are used ambiguously and inconsistently,and different terms are commonly used to express the same concept.This paper discusses computational design(CD)and proposes an improved and sound taxonomy for a set of key CD terms,namely,parametric,generative,and algorithmic design,based on an extensive literature review from which different definitions by various authors were collected,analyzed,and compared.展开更多
Many Beijing Siheyuan,a type of Chinese vernacular housing with significant cultural value,have been lost in recent years.Preserving the few remaining has become a necessity,but many contemporary architects lack an un...Many Beijing Siheyuan,a type of Chinese vernacular housing with significant cultural value,have been lost in recent years.Preserving the few remaining has become a necessity,but many contemporary architects lack an understanding of their design principles.Based on a historical analysis deriving from Fengshui theory,the Gongchens Zuofa Zeli ancient construction manual,and craftsmen's experience,this paper describes a parametric algorithm capable of producing Siheyuan variants within a 4D CAD environment which by transforming the original design principles into an algorithm contributes to an understanding of Siheyuan typology and their preservation.This algorithm was implemented in a virtual scripting environment to generate accurate virtual counterparts of historical orextant Siheyuan houses revealing the tacit computational rules underlying traditional Chinese architecture.展开更多
Architectural representation encompasses the means used to describe architectural entities.This discipline has long been under constant change due to architects’everpresent desire for innovation.Algorithmic design(AD...Architectural representation encompasses the means used to describe architectural entities.This discipline has long been under constant change due to architects’everpresent desire for innovation.Algorithmic design(AD)is currently making its way into the plethora of representation methods that integrate the architect’s day-to-day work tools.However,it provides its fair share of controversy and hardship as it goes.This paper assesses whether AD is suitable as a representation method for architectural design by making a systematic analysis of this medium as a contemporary representation method.Specifically,we investigate(1)its birth and evolution as a means of representation,(2)the characteristics that make it simultaneously appealing and off-putting to the architectural community,(3)the influence of technological evolution and education on its proliferation,and(4)its capacity to represent design problems in comparison to the currently predominant means of digital architectural representation,that is,computer-aided drafting and building information modeling.展开更多
This paper reforms the shortcomings and difficulties in the teaching process of the“Algorithm Design and Analysis”course.The knowledge graph optimizes the teaching content,abandons the traditional teaching method,ca...This paper reforms the shortcomings and difficulties in the teaching process of the“Algorithm Design and Analysis”course.The knowledge graph optimizes the teaching content,abandons the traditional teaching method,captures the direction of talent demand,adjusts the class time allocation,reorganizes the assessment method,focuses on practical hands-on ability,and designs a multistage teaching quality evaluation system to promote the overall improvement of teaching quality.The practice of course reform has proven that the“Algorithm Design and Analysis”course has achieved good teaching results after a series of teaching reform measures.展开更多
“Algorithm Design and Analysis”is not only one of the important courses in the undergraduate teaching of computer science and technology but also a key part of computer professional skills.In recent years,with the r...“Algorithm Design and Analysis”is not only one of the important courses in the undergraduate teaching of computer science and technology but also a key part of computer professional skills.In recent years,with the rise and widespread application of big language models,many teaching reform plans have been produced to promote the quality and efficiency of teaching.This paper studies how to refer to software development professional skills standards,investigates the knowledge points of“Algorithm Design and Analysis”courses in other educational institutions,uses cutting-edge core technology big language models to drive the improvement of teaching evaluation methods,improves teaching efficiency,and carries out reforms and practices in teaching content for undergraduate students in computer science.展开更多
A design approach is presented in this paper for underactuation in robotic finger mechanisms. The characters of underactuated finger mechanisms are introduced as based on linkage and spring systems. The feature of sel...A design approach is presented in this paper for underactuation in robotic finger mechanisms. The characters of underactuated finger mechanisms are introduced as based on linkage and spring systems. The feature of self-adaptive enveloping grasp by underactuated finger mechanisms is discussed with feasible in grasping unknown objects. The design problem of robotic fingers is analyzed by looking at many aspects for an optimal functionality. Design problems and requirements for underactuated mechanisms are formulated as related to human-like robotic fingers. In particular, characteristics of finger mechanisms are analyzed and optimality criteria are summarized with the aim to formulate a general design algorithm. A general multi-objective optimization design approach is applied as based on a suitable optimization problem by using suitable expressions of optimality criteria. An example is illustrated as an improvement of finger mechanism in Laboratory of Robotics and Mechatronics （LARM） Hand. Results of design outputs and grasp simulations are reported with the aim to show the practical feasibility of the proposed concepts and computations.展开更多
Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorith...Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorithm so as to exploit special features of the hardware and avoid associated architecture shortcomings. This paper presents an investigation into the analysis and design mechanisms that will lead to reduction in the execution time in implementing real-time control algorithms. The proposed mechanisms are exemplified by means of one algorithm, which demonstrates their applicability to real-time applications. An active vibration control （AVC） algorithm for a flexible beam system simulated using the finite difference （FD） method is considered to demonstrate the effectiveness of the proposed methods. A comparative performance evaluation of the proposed design mechanisms is presented and discussed through a set of experiments.展开更多
Advanced engineering systems, like aircraft, are defined by tens or even hundreds of design variables. Building an accurate surrogate model for use in such high-dimensional optimization problems is a difficult task ow...Advanced engineering systems, like aircraft, are defined by tens or even hundreds of design variables. Building an accurate surrogate model for use in such high-dimensional optimization problems is a difficult task owing to the curse of dimensionality. This paper presents a new algorithm to reduce the size of a design space to a smaller region of interest allowing a more accurate surrogate model to be generated. The framework requires a set of models of different physical or numerical fidelities. The low-fidelity （LF） model provides physics-based approximation of the high-fidelity （HF） model at a fraction of the computational cost. It is also instrumental in identifying the small region of interest in the design space that encloses the high-fidelity optimum. A surrogate model is then constructed to match the low-fidelity model to the high-fidelity model in the identified region of interest. The optimization process is managed by an update strategy to prevent convergence to false optima. The algorithm is applied on mathematical problems and a two-dimen-sional aerodynamic shape optimization problem in a variable-fidelity context. Results obtained are in excellent agreement with high-fidelity results, even with lower-fidelity flow solvers, while showing up to 39% time savings.展开更多
The plow of the submarine plowing trencher is one of the main functional mechanisms, and its optimization is very important. The design parameters play a very significant role in determining the requirements of the to...The plow of the submarine plowing trencher is one of the main functional mechanisms, and its optimization is very important. The design parameters play a very significant role in determining the requirements of the towing force of a vessel. A multi-objective genetic algorithm based on analytical models of the plow surface has been examined and applied in efforts to obtain optimal design of the plow. For a specific soil condition, the draft force and moldboard surface area which are the key parameters in the working process of the plow are optimized by finding the corresponding optimal values of the plow blade penetration angle and two surface angles of the main cutting blade of the plow. Parameters such as the moldboard side angle of deviation, moldboard lift angle, angular variation of the tangent line, and the spanning length are also analyzed with respect to the force of the moldboard surface along soil flow direction. Results show that the optimized plow has an improved plow performance. The draft forces of the main cutting blade and the moldboard are 10.6% and 7%, respectively, less than the original design. The standard deviation of Gaussian curvature of moldboard is lowered by 64.5%, which implies that the smoothness of the optimized moldboard surface is much greater than the original.展开更多
K-mer can be used for the description of biological sequences and k-mer distribution is a tool for solving sequences analysis problems in bioinformatics.We can use k-mer vector as a representation method of the k-mer ...K-mer can be used for the description of biological sequences and k-mer distribution is a tool for solving sequences analysis problems in bioinformatics.We can use k-mer vector as a representation method of the k-mer distribution of the biological sequence.Problems,such as similarity calculations or sequence assembly,can be described in the k-mer vector space.It helps us to identify new features of an old sequence-based problem in bioinformatics and develop new algorithms using the concepts and methods from linear space theory.In this study,we defined the k-mer vector space for the generalized biological sequences.The meaning of corresponding vector operations is explained in the biological context.We presented the vector/matrix form of several widely seen sequence-based problems,including read quantification,sequence assembly,and pattern detection problem.Its advantages and disadvantages are discussed.Also,we implement a tool for the sequence assembly problem based on the concepts of k-mer vector methods.It shows the practicability and convenience of this algorithm design strategy.展开更多
The neutron supermirror is an important neutron optical device that can significantly improve the efficiency of neutron transport in neutron guides and has been widely used in research neutron sources.Three types of a...The neutron supermirror is an important neutron optical device that can significantly improve the efficiency of neutron transport in neutron guides and has been widely used in research neutron sources.Three types of algorithms,including approximately ten algorithms,have been developed for designing high-efficiency supermirror structures.In addition to its applications in neutron guides,in recent years,the use of neutron supermirrors in neutronfocusing mirrors has been proposed to advance the development of neutron scattering and neutron imaging instruments,especially those at compact neutron sources.In this new application scenario,the performance of supermirrors strongly affects the instrument performance;therefore,a careful evaluation of the design algorithms is needed.In this study,we examine two issues:the effect of nonuniform film thickness distribution on a curved substrate and the effect of the specific neutron intensity distribution on the performance of neutron supermirrors designed using existing algorithms.The effect of film thickness nonuniformity is found to be relatively insignificant,whereas the effect of the neutron intensity distribution over Q(where Q is the magnitude of the scattering vector of incident neutrons)is considerable.Selection diagrams that show the best design algorithm under different conditions are obtained from these results.When the intensity distribution is not considered,empirical algorithms can obtain the highest average reflectivity,whereas discrete algorithms perform best when the intensity distribution is taken into account.The reasons for the differences in performance between algorithms are also discussed.These findings provide a reference for selecting design algorithms for supermirrors for use in neutron optical devices with unique geometries and can be very helpful for improving the performance of focusing supermirror-based instruments.展开更多
The purpose of computer-aided design of new adaptive pulsed arc technologies of welding is: to de- sign optimum algorithms of pulsed control over main energy parameters of welding.It permits:to in- crease welding ...The purpose of computer-aided design of new adaptive pulsed arc technologies of welding is: to de- sign optimum algorithms of pulsed control over main energy parameters of welding.It permits:to in- crease welding productivity, to stabilize the welding regime, to control weld formation,taking into ac- count its spatial position, to proveal specie strength of the welded and coatings. Computer- aided design reduces the time of development of new pulsed arc technology:provides the optimization of technological referes according to the operating conditions of welded joints,the prediction of the ser- vice life of the welds.The developed methodology of computer-aided design of advanced technologies, models, original software, adaptive algorithms of pulsed control, and spend equipment permits to regulate penetration,the weld shape, the sizes of heat - affected zone; to predict sired properties and quality of welded joints.展开更多
Obtaining the optimal values of the parameters for th e design of a required mould and the operation of the moulding process are diffi cult, this is due to the complexity of product geometry and the variation of pla s...Obtaining the optimal values of the parameters for th e design of a required mould and the operation of the moulding process are diffi cult, this is due to the complexity of product geometry and the variation of pla stic material properties. The typical parameters for the mould design and mouldi ng process are melt flow length, injection pressure, holding pressure, back pres sure, injection speed, melt temperature, mould temperature, clamping force, inje ction time, holding time and cooling time. This paper discusses the difficulties of using the current computer aided optimization methods to acquire the values of the parameters. A method that is based on the concept of genetic algorithm is proposed to overcome the difficulties. The proposed method describes in details on how to attain the optimal values of the parameters form a given product geom etry.展开更多
In order to shorten the design period, the paper describes a new optimization strategy for computationally expensive design optimization of turbomachinery, combined with design of experiment (DOE), response surface mo...In order to shorten the design period, the paper describes a new optimization strategy for computationally expensive design optimization of turbomachinery, combined with design of experiment (DOE), response surface models (RSM), genetic algorithm (GA) and a 3-D Navier-Stokes solver(Numeca Fine). Data points for response evaluations were selected by improved distributed hypercube sampling (IHS) and the 3-D Navier-Stokes analysis was carried out at these sample points. The quadratic response surface model was used to approximate the relationships between the design variables and flow parameters. To maximize the adiabatic efficiency, the genetic algorithm was applied to the response surface model to perform global optimization to achieve the optimum design of NASA Stage 35. An optimum leading edge line was found, which produced a new 3-D rotor blade combined with sweep and lean, and a new stator one with skew. It is concluded that the proposed strategy can provide a reliable method for design optimization of turbomachinery blades at reasonable computing cost.展开更多
The design of roof frame is one of the most important parts of LNG tank design.In China,however,the calculation of roof frame system of extra-large LNG tanks is currently faced with a series of problems.For example,th...The design of roof frame is one of the most important parts of LNG tank design.In China,however,the calculation of roof frame system of extra-large LNG tanks is currently faced with a series of problems.For example,there is no united yardstick on buckling characteristic value,the calculation is based on many assumptions,and the calculation is inconsistent with domestic specifications and stipulations.In view of these problems,the material non-linearity and structural non-linearity were introduced and the initial defect was taken into consideration.Then,the large non-linear finite element calculation software ABAQUS was adopted to carry out modeling on the roof frame and liner system of extra-large LNG tanks and calculate and analyze the force applied on them and their stability.Finally,a complete set of design algorithm for the roof frame and liner system of extra-large LNG tanks was established and applied to the design of a certain LNG tank(20×10^(4)m^(3))in China.It is indicated that this design algorithm can simulate the actual situations accurately.This design algorithm is structurally composed of shell units and beam units,and it is connected in the pattern of common node.Besides,force calculation is conducted in 10 operational modes and the buckling calculation in 7 operational modes,including all operational modes in the construction process of roof frame and liner system of LNG tanks.It is also revealed that the maximum stress on the roof frame is 125.7 MPa,that on the liner is 101.4 MPa and the minimum safety coefficient used for buckling calculation is 2.57.Under this system,the force and stability of the roof frame of LNG tanks are satisfactory.The research results can be used as reference for relevant design and calculation.展开更多
Considering the essential and influential role of centrifugal compressors in a wide range of industries makes most of engineers research and study on design and optimization of centrifugal compressors. Centrifugal com...Considering the essential and influential role of centrifugal compressors in a wide range of industries makes most of engineers research and study on design and optimization of centrifugal compressors. Centrifugal compressors are the key to part ofoil, gas and petrochemical industries as well as gas pipeline transports. Since complete 3D design of the compressor consumes a considerable amount of time, most of active companies in the field, are profoundly interested in obtaining a design outline before taking any further steps in designing the entire machine. In this paper, a numerical algorithm, named ACDA （adapted compressor design algorithm） for fast and accurate preliminary design of centrifugal compressor is presented. The design procedure is obtained under real gas behavior, using an appropriate equation of state. Starting from impeller inlet, the procedure is continued on by resulting in numerical calculation for other sections including impeller exit, volute and exit diffuser. Clearly, in any step suitable correction factors are employed in order to conclude in precise numerical results. Finally, the achieved design result is compared with available reference data.展开更多
Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optic...Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks（i.e., target detection and tracking）. We then propose a new non-dominated sorting genetic algorithm（NSGA） to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.展开更多
As society confronts increasingly complex demands and the growing need for carbon-neutral architecture,AI-driven design methodologies are evolving rapidly.However,the lack of a unified integration platform in the desi...As society confronts increasingly complex demands and the growing need for carbon-neutral architecture,AI-driven design methodologies are evolving rapidly.However,the lack of a unified integration platform in the design process continues to hinder AI’s integration into real-world workflows.To address this challenge,we introduce ArchiWeb,a web-based platform specifically built to support AI-driven processes in early-stage architectural design.ArchiWeb transforms architectural representation and problem formulation by utilizing lightweight data protocols and a modular algorithmic network within an interactive web environment.Through its cloud-native,open-architecture framework,ArchiWeb enables deeper integration of AI technologies while accelerating the accumulation,sharing,and reuse of design knowledge across projects and disciplines.Ultimately,ArchiWeb aims to drive architectural design toward greater intelligence,efficiency,and sustainability-supporting the transition to data-informed,computationally enabled,and environmentally responsible design practices.展开更多
The product family design problem solved by evolutionary algorithms is discussed. A successful product family design method should achieve an optimal tradeoff among a set of competing objectives, which involves maximi...The product family design problem solved by evolutionary algorithms is discussed. A successful product family design method should achieve an optimal tradeoff among a set of competing objectives, which involves maximizing commonality across the family of products and optimizing the performances of each product in the family. A 2-level chromosome structured genetic algorithm （2LCGA） is proposed to solve this class of problems and its performance is analyzed in comparing its results with those obtained with other methods. By interpreting the chromosome as a 2-level linear structure, the variable commonality genetic algorithm （GA） is constructed to vary the amount of platform commonality and automatically searches across varying levels of commonality for the platform while trying to resolve the tradeoff between commonality and individual product performance within the product family during optimization process. By incorporating a commonality assessing index to the problem formulation, the 2LCGA optimize the product platform and its corresponding family of products in a single stage, which can yield improvements in the overall performance of the product family compared with two-stage approaches （the first stage involves determining the best settings for the platform variables and values of unique variables are found for each product in the second stage）. The scope of the algorithm is also expanded by introducing a classification mechanism to allow mul- tiple platforms to be considered during product family optimization, offering opportunities for superior overall design by more efficacious tradeoffs between commonality and performance. The effectiveness of 2LCGA is demonstrated through the design of a family of universal electric motors and comparison against previous results.展开更多
Data center networks may comprise tens or hundreds of thousands of nodes,and,naturally,suffer from frequent software and hardware failures as well as link congestions.Packets are routed along the shortest paths with s...Data center networks may comprise tens or hundreds of thousands of nodes,and,naturally,suffer from frequent software and hardware failures as well as link congestions.Packets are routed along the shortest paths with sufficient resources to facilitate efficient network utilization and minimize delays.In such dynamic networks,links frequently fail or get congested,making the recalculation of the shortest paths a computationally intensive problem.Various routing protocols were proposed to overcome this problem by focusing on network utilization rather than speed.Surprisingly,the design of fast shortest-path algorithms for data centers was largely neglected,though they are universal components of routing protocols.Moreover,parallelization techniques were mostly deployed for random network topologies,and not for regular topologies that are often found in data centers.The aim of this paper is to improve scalability and reduce the time required for the shortest-path calculation in data center networks by parallelization on general-purpose hardware.We propose a novel algorithm that parallelizes edge relaxations as a faster and more scalable solution for popular data center topologies.展开更多
基金This work was supported by national funds through Fundacao para a Ciencia-a Tecnologia(FCT)with references UID/CEC/50021/2019 and PTDC/ART-DAQ/31061/2017by the PhD grants under contract of FCT with references SFRH/BD/128628/2017 and SFRH/BD/98658/2013,and by the PhD grant under contract of University of Lisbon(UL),Instituto Superior Tecnico(IST)and the research unit Investigacao-Inovacao em Engenharia Civil para a Sustentabilidade(CERIS).
文摘Computation-based approaches in design have emerged in the last decades and rapidly became popular among architects and other designers.Design professionals and researchers adopted different terminologies to address these approaches.However,some terms are used ambiguously and inconsistently,and different terms are commonly used to express the same concept.This paper discusses computational design(CD)and proposes an improved and sound taxonomy for a set of key CD terms,namely,parametric,generative,and algorithmic design,based on an extensive literature review from which different definitions by various authors were collected,analyzed,and compared.
基金supported by the funding from The China Scholarship Council(No.201708510109).
文摘Many Beijing Siheyuan,a type of Chinese vernacular housing with significant cultural value,have been lost in recent years.Preserving the few remaining has become a necessity,but many contemporary architects lack an understanding of their design principles.Based on a historical analysis deriving from Fengshui theory,the Gongchens Zuofa Zeli ancient construction manual,and craftsmen's experience,this paper describes a parametric algorithm capable of producing Siheyuan variants within a 4D CAD environment which by transforming the original design principles into an algorithm contributes to an understanding of Siheyuan typology and their preservation.This algorithm was implemented in a virtual scripting environment to generate accurate virtual counterparts of historical orextant Siheyuan houses revealing the tacit computational rules underlying traditional Chinese architecture.
基金This work was supported by national funds through Fundacao para a Ciencia e a Tecnologia(FCT)(references UIDB/50021/2020,PTDC/ART-DAQ/31061/2017)PhD grants under contract of FCT(grant numbers SFRH/BD/128628/2017,DFA/BD/4682/2020).
文摘Architectural representation encompasses the means used to describe architectural entities.This discipline has long been under constant change due to architects’everpresent desire for innovation.Algorithmic design(AD)is currently making its way into the plethora of representation methods that integrate the architect’s day-to-day work tools.However,it provides its fair share of controversy and hardship as it goes.This paper assesses whether AD is suitable as a representation method for architectural design by making a systematic analysis of this medium as a contemporary representation method.Specifically,we investigate(1)its birth and evolution as a means of representation,(2)the characteristics that make it simultaneously appealing and off-putting to the architectural community,(3)the influence of technological evolution and education on its proliferation,and(4)its capacity to represent design problems in comparison to the currently predominant means of digital architectural representation,that is,computer-aided drafting and building information modeling.
基金supported by Harbin Engineering University’s 2021 Education Reform Project“How to Make Computer Theory Teaching Serve Employment”(Grant No.JG2021B0609).
文摘This paper reforms the shortcomings and difficulties in the teaching process of the“Algorithm Design and Analysis”course.The knowledge graph optimizes the teaching content,abandons the traditional teaching method,captures the direction of talent demand,adjusts the class time allocation,reorganizes the assessment method,focuses on practical hands-on ability,and designs a multistage teaching quality evaluation system to promote the overall improvement of teaching quality.The practice of course reform has proven that the“Algorithm Design and Analysis”course has achieved good teaching results after a series of teaching reform measures.
基金supported by Harbin Engineering University’s 2021 Education Reform Project“How to Make Computer Theory Teaching Serve Employment”(Grant No.JG2021B0609).
文摘“Algorithm Design and Analysis”is not only one of the important courses in the undergraduate teaching of computer science and technology but also a key part of computer professional skills.In recent years,with the rise and widespread application of big language models,many teaching reform plans have been produced to promote the quality and efficiency of teaching.This paper studies how to refer to software development professional skills standards,investigates the knowledge points of“Algorithm Design and Analysis”courses in other educational institutions,uses cutting-edge core technology big language models to drive the improvement of teaching evaluation methods,improves teaching efficiency,and carries out reforms and practices in teaching content for undergraduate students in computer science.
基金supported by Key International S&T Cooperation Project (Grant No. 2008DFA81280)Part of this work has been developed within the project No.27 of the Italy-China program 2006–2009+1 种基金A joined study of first author at Laboratory of Robotics and Mechatronics (LARM) during 2007–2008 has been supported by state scholarship program of China Scholarship Council (CSC)Innovation Foundation of Beijing University of Aeronautics and Astronautics (BUAA) for PhD Graduates
文摘A design approach is presented in this paper for underactuation in robotic finger mechanisms. The characters of underactuated finger mechanisms are introduced as based on linkage and spring systems. The feature of self-adaptive enveloping grasp by underactuated finger mechanisms is discussed with feasible in grasping unknown objects. The design problem of robotic fingers is analyzed by looking at many aspects for an optimal functionality. Design problems and requirements for underactuated mechanisms are formulated as related to human-like robotic fingers. In particular, characteristics of finger mechanisms are analyzed and optimality criteria are summarized with the aim to formulate a general design algorithm. A general multi-objective optimization design approach is applied as based on a suitable optimization problem by using suitable expressions of optimality criteria. An example is illustrated as an improvement of finger mechanism in Laboratory of Robotics and Mechatronics （LARM） Hand. Results of design outputs and grasp simulations are reported with the aim to show the practical feasibility of the proposed concepts and computations.
文摘Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorithm so as to exploit special features of the hardware and avoid associated architecture shortcomings. This paper presents an investigation into the analysis and design mechanisms that will lead to reduction in the execution time in implementing real-time control algorithms. The proposed mechanisms are exemplified by means of one algorithm, which demonstrates their applicability to real-time applications. An active vibration control （AVC） algorithm for a flexible beam system simulated using the finite difference （FD） method is considered to demonstrate the effectiveness of the proposed methods. A comparative performance evaluation of the proposed design mechanisms is presented and discussed through a set of experiments.
文摘Advanced engineering systems, like aircraft, are defined by tens or even hundreds of design variables. Building an accurate surrogate model for use in such high-dimensional optimization problems is a difficult task owing to the curse of dimensionality. This paper presents a new algorithm to reduce the size of a design space to a smaller region of interest allowing a more accurate surrogate model to be generated. The framework requires a set of models of different physical or numerical fidelities. The low-fidelity （LF） model provides physics-based approximation of the high-fidelity （HF） model at a fraction of the computational cost. It is also instrumental in identifying the small region of interest in the design space that encloses the high-fidelity optimum. A surrogate model is then constructed to match the low-fidelity model to the high-fidelity model in the identified region of interest. The optimization process is managed by an update strategy to prevent convergence to false optima. The algorithm is applied on mathematical problems and a two-dimen-sional aerodynamic shape optimization problem in a variable-fidelity context. Results obtained are in excellent agreement with high-fidelity results, even with lower-fidelity flow solvers, while showing up to 39% time savings.
基金Supported the National Natural Science Foundation of China （No. 51179040） Natural Science Foundation of Heilongjiang Province （No. E200904）
文摘The plow of the submarine plowing trencher is one of the main functional mechanisms, and its optimization is very important. The design parameters play a very significant role in determining the requirements of the towing force of a vessel. A multi-objective genetic algorithm based on analytical models of the plow surface has been examined and applied in efforts to obtain optimal design of the plow. For a specific soil condition, the draft force and moldboard surface area which are the key parameters in the working process of the plow are optimized by finding the corresponding optimal values of the plow blade penetration angle and two surface angles of the main cutting blade of the plow. Parameters such as the moldboard side angle of deviation, moldboard lift angle, angular variation of the tangent line, and the spanning length are also analyzed with respect to the force of the moldboard surface along soil flow direction. Results show that the optimized plow has an improved plow performance. The draft forces of the main cutting blade and the moldboard are 10.6% and 7%, respectively, less than the original design. The standard deviation of Gaussian curvature of moldboard is lowered by 64.5%, which implies that the smoothness of the optimized moldboard surface is much greater than the original.
基金the National Natural Science Foundation of China(11771393,11632015)the Natural Sci-ence Foundation of Zhejiang Province,China(LZ14A010002).
文摘K-mer can be used for the description of biological sequences and k-mer distribution is a tool for solving sequences analysis problems in bioinformatics.We can use k-mer vector as a representation method of the k-mer distribution of the biological sequence.Problems,such as similarity calculations or sequence assembly,can be described in the k-mer vector space.It helps us to identify new features of an old sequence-based problem in bioinformatics and develop new algorithms using the concepts and methods from linear space theory.In this study,we defined the k-mer vector space for the generalized biological sequences.The meaning of corresponding vector operations is explained in the biological context.We presented the vector/matrix form of several widely seen sequence-based problems,including read quantification,sequence assembly,and pattern detection problem.Its advantages and disadvantages are discussed.Also,we implement a tool for the sequence assembly problem based on the concepts of k-mer vector methods.It shows the practicability and convenience of this algorithm design strategy.
基金supported by the National Natural Science Foundation of China (Nos. 12027810 and 11322548)
文摘The neutron supermirror is an important neutron optical device that can significantly improve the efficiency of neutron transport in neutron guides and has been widely used in research neutron sources.Three types of algorithms,including approximately ten algorithms,have been developed for designing high-efficiency supermirror structures.In addition to its applications in neutron guides,in recent years,the use of neutron supermirrors in neutronfocusing mirrors has been proposed to advance the development of neutron scattering and neutron imaging instruments,especially those at compact neutron sources.In this new application scenario,the performance of supermirrors strongly affects the instrument performance;therefore,a careful evaluation of the design algorithms is needed.In this study,we examine two issues:the effect of nonuniform film thickness distribution on a curved substrate and the effect of the specific neutron intensity distribution on the performance of neutron supermirrors designed using existing algorithms.The effect of film thickness nonuniformity is found to be relatively insignificant,whereas the effect of the neutron intensity distribution over Q(where Q is the magnitude of the scattering vector of incident neutrons)is considerable.Selection diagrams that show the best design algorithm under different conditions are obtained from these results.When the intensity distribution is not considered,empirical algorithms can obtain the highest average reflectivity,whereas discrete algorithms perform best when the intensity distribution is taken into account.The reasons for the differences in performance between algorithms are also discussed.These findings provide a reference for selecting design algorithms for supermirrors for use in neutron optical devices with unique geometries and can be very helpful for improving the performance of focusing supermirror-based instruments.
文摘The purpose of computer-aided design of new adaptive pulsed arc technologies of welding is: to de- sign optimum algorithms of pulsed control over main energy parameters of welding.It permits:to in- crease welding productivity, to stabilize the welding regime, to control weld formation,taking into ac- count its spatial position, to proveal specie strength of the welded and coatings. Computer- aided design reduces the time of development of new pulsed arc technology:provides the optimization of technological referes according to the operating conditions of welded joints,the prediction of the ser- vice life of the welds.The developed methodology of computer-aided design of advanced technologies, models, original software, adaptive algorithms of pulsed control, and spend equipment permits to regulate penetration,the weld shape, the sizes of heat - affected zone; to predict sired properties and quality of welded joints.
文摘Obtaining the optimal values of the parameters for th e design of a required mould and the operation of the moulding process are diffi cult, this is due to the complexity of product geometry and the variation of pla stic material properties. The typical parameters for the mould design and mouldi ng process are melt flow length, injection pressure, holding pressure, back pres sure, injection speed, melt temperature, mould temperature, clamping force, inje ction time, holding time and cooling time. This paper discusses the difficulties of using the current computer aided optimization methods to acquire the values of the parameters. A method that is based on the concept of genetic algorithm is proposed to overcome the difficulties. The proposed method describes in details on how to attain the optimal values of the parameters form a given product geom etry.
文摘In order to shorten the design period, the paper describes a new optimization strategy for computationally expensive design optimization of turbomachinery, combined with design of experiment (DOE), response surface models (RSM), genetic algorithm (GA) and a 3-D Navier-Stokes solver(Numeca Fine). Data points for response evaluations were selected by improved distributed hypercube sampling (IHS) and the 3-D Navier-Stokes analysis was carried out at these sample points. The quadratic response surface model was used to approximate the relationships between the design variables and flow parameters. To maximize the adiabatic efficiency, the genetic algorithm was applied to the response surface model to perform global optimization to achieve the optimum design of NASA Stage 35. An optimum leading edge line was found, which produced a new 3-D rotor blade combined with sweep and lean, and a new stator one with skew. It is concluded that the proposed strategy can provide a reliable method for design optimization of turbomachinery blades at reasonable computing cost.
基金Project supported by the Special and Significant Project of China National Offshore Oil Corporation“Study on the design of full-containment large LNG storage tank and engineering applications”(No.:CNOOC-KJ125ZDXM14QD-04QD11).
文摘The design of roof frame is one of the most important parts of LNG tank design.In China,however,the calculation of roof frame system of extra-large LNG tanks is currently faced with a series of problems.For example,there is no united yardstick on buckling characteristic value,the calculation is based on many assumptions,and the calculation is inconsistent with domestic specifications and stipulations.In view of these problems,the material non-linearity and structural non-linearity were introduced and the initial defect was taken into consideration.Then,the large non-linear finite element calculation software ABAQUS was adopted to carry out modeling on the roof frame and liner system of extra-large LNG tanks and calculate and analyze the force applied on them and their stability.Finally,a complete set of design algorithm for the roof frame and liner system of extra-large LNG tanks was established and applied to the design of a certain LNG tank(20×10^(4)m^(3))in China.It is indicated that this design algorithm can simulate the actual situations accurately.This design algorithm is structurally composed of shell units and beam units,and it is connected in the pattern of common node.Besides,force calculation is conducted in 10 operational modes and the buckling calculation in 7 operational modes,including all operational modes in the construction process of roof frame and liner system of LNG tanks.It is also revealed that the maximum stress on the roof frame is 125.7 MPa,that on the liner is 101.4 MPa and the minimum safety coefficient used for buckling calculation is 2.57.Under this system,the force and stability of the roof frame of LNG tanks are satisfactory.The research results can be used as reference for relevant design and calculation.
文摘Considering the essential and influential role of centrifugal compressors in a wide range of industries makes most of engineers research and study on design and optimization of centrifugal compressors. Centrifugal compressors are the key to part ofoil, gas and petrochemical industries as well as gas pipeline transports. Since complete 3D design of the compressor consumes a considerable amount of time, most of active companies in the field, are profoundly interested in obtaining a design outline before taking any further steps in designing the entire machine. In this paper, a numerical algorithm, named ACDA （adapted compressor design algorithm） for fast and accurate preliminary design of centrifugal compressor is presented. The design procedure is obtained under real gas behavior, using an appropriate equation of state. Starting from impeller inlet, the procedure is continued on by resulting in numerical calculation for other sections including impeller exit, volute and exit diffuser. Clearly, in any step suitable correction factors are employed in order to conclude in precise numerical results. Finally, the achieved design result is compared with available reference data.
文摘Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks（i.e., target detection and tracking）. We then propose a new non-dominated sorting genetic algorithm（NSGA） to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.
基金funded by the National Natural Science Foundation of China(No.52378008)Postgraduate Research Innovation Program of Jiangsu Province(No.KYCX22_0189).
文摘As society confronts increasingly complex demands and the growing need for carbon-neutral architecture,AI-driven design methodologies are evolving rapidly.However,the lack of a unified integration platform in the design process continues to hinder AI’s integration into real-world workflows.To address this challenge,we introduce ArchiWeb,a web-based platform specifically built to support AI-driven processes in early-stage architectural design.ArchiWeb transforms architectural representation and problem formulation by utilizing lightweight data protocols and a modular algorithmic network within an interactive web environment.Through its cloud-native,open-architecture framework,ArchiWeb enables deeper integration of AI technologies while accelerating the accumulation,sharing,and reuse of design knowledge across projects and disciplines.Ultimately,ArchiWeb aims to drive architectural design toward greater intelligence,efficiency,and sustainability-supporting the transition to data-informed,computationally enabled,and environmentally responsible design practices.
基金This project is supported by National Natural Science Foundation of China(No.70471022,No.70501021)the Joint Research Scheme of National Natural Science Foundation of China(No,70418013) Hong Kong Research Grant Council,China(No.N_HKUST625/04).
文摘The product family design problem solved by evolutionary algorithms is discussed. A successful product family design method should achieve an optimal tradeoff among a set of competing objectives, which involves maximizing commonality across the family of products and optimizing the performances of each product in the family. A 2-level chromosome structured genetic algorithm （2LCGA） is proposed to solve this class of problems and its performance is analyzed in comparing its results with those obtained with other methods. By interpreting the chromosome as a 2-level linear structure, the variable commonality genetic algorithm （GA） is constructed to vary the amount of platform commonality and automatically searches across varying levels of commonality for the platform while trying to resolve the tradeoff between commonality and individual product performance within the product family during optimization process. By incorporating a commonality assessing index to the problem formulation, the 2LCGA optimize the product platform and its corresponding family of products in a single stage, which can yield improvements in the overall performance of the product family compared with two-stage approaches （the first stage involves determining the best settings for the platform variables and values of unique variables are found for each product in the second stage）. The scope of the algorithm is also expanded by introducing a classification mechanism to allow mul- tiple platforms to be considered during product family optimization, offering opportunities for superior overall design by more efficacious tradeoffs between commonality and performance. The effectiveness of 2LCGA is demonstrated through the design of a family of universal electric motors and comparison against previous results.
基金This work was supported by the Serbian Ministry of Science and Education(project TR-32022)by companies Telekom Srbija and Informatika.
文摘Data center networks may comprise tens or hundreds of thousands of nodes,and,naturally,suffer from frequent software and hardware failures as well as link congestions.Packets are routed along the shortest paths with sufficient resources to facilitate efficient network utilization and minimize delays.In such dynamic networks,links frequently fail or get congested,making the recalculation of the shortest paths a computationally intensive problem.Various routing protocols were proposed to overcome this problem by focusing on network utilization rather than speed.Surprisingly,the design of fast shortest-path algorithms for data centers was largely neglected,though they are universal components of routing protocols.Moreover,parallelization techniques were mostly deployed for random network topologies,and not for regular topologies that are often found in data centers.The aim of this paper is to improve scalability and reduce the time required for the shortest-path calculation in data center networks by parallelization on general-purpose hardware.We propose a novel algorithm that parallelizes edge relaxations as a faster and more scalable solution for popular data center topologies.
