Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining...Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.展开更多
This research explores the design and implementation of an AI-driven Single Window system for international trade,aimed at enhancing data integration,risk assessment,and decision-making processes.The study focuses on ...This research explores the design and implementation of an AI-driven Single Window system for international trade,aimed at enhancing data integration,risk assessment,and decision-making processes.The study focuses on developing a modular,scalable architec-ture that integrates various AI technologies,including machine learning and natural lan-guage processing(NLP),to address inefficiencies in existing systems.The proposed system demonstrates improvements in customs clearance efficiency,risk detection accuracy,and supply chain management.Through detailed case studies,the effectiveness of the AI-driven Single Window system is evaluated,highlighting its impact on port management,interna-tional logistics,and overall trade facilitation.The findings suggest that the integration of AI into Single Window systems can lead to significant advancements in trade efficiency,transparency,and stakeholder collaboration.展开更多
This paper explores the role of Artificial Intelligence(AI)in enhancing trade facilitation through its integration with Single Window Systems(SWS).It investigates how AI tech-nologies such as machine learning,natural ...This paper explores the role of Artificial Intelligence(AI)in enhancing trade facilitation through its integration with Single Window Systems(SWS).It investigates how AI tech-nologies such as machine learning,natural language processing,and predictive analytics can improve the efficiency and effectiveness of trade processes.Case studies of Singapore and Australia are analyzed to highlight successful AI applications and key lessons learned.The study discusses the benefits,including increased efficiency,reduced costs,enhanced accuracy,and improved user experience,alongside the challenges posed by technical com-plexities,legal and ethical considerations,and resistance to change.The paper also pro-vides policy implications and recommendations for governments,international organiza-tions,and private sector stakeholders.Future research directions emphasize emerging AI technologies like AI-driven blockchain and advanced NLP,and their potential long-term impacts on global trade dynamics.展开更多
Compared to fixed virtual window algorithm(FVWA),the dynamic virtual window algorithm(DVWA)determines the length of each virtual container according to the sizes of goods of each order,which saves space of virtual con...Compared to fixed virtual window algorithm(FVWA),the dynamic virtual window algorithm(DVWA)determines the length of each virtual container according to the sizes of goods of each order,which saves space of virtual containers and improves the picking efficiency.However,the interval of consecutive goods caused by dispensers on conveyor can not be eliminated by DVWA,which limits a further improvement of picking efficiency.In order to solve this problem,a compressible virtual window algorithm(CVWA)is presented.It not only inherits the merit of DVWA but also compresses the length of virtual containers without congestion of order accumulation by advancing the beginning time of order picking and reasonably coordinating the pace of order accumulation.The simulation result proves that the picking efficiency of automated sorting system is greatly improved by CVWA.展开更多
This paper describes a method for building hot snapshot copy based on windows-file system （HSCF）. The architecture and running mechanism of HSCF are discussed after giving a comparison with other on-line backup tecb...This paper describes a method for building hot snapshot copy based on windows-file system （HSCF）. The architecture and running mechanism of HSCF are discussed after giving a comparison with other on-line backup tecbnology. HSCF, based on a file system filter driver, protects computer data and ensures their integrity and consistency with following three steps： access to open files, synchronization and copy on-write. Its strategies for improving system performance are analyzed including priority setting, incremental snapshot and load balance. HSCF is a new kind of snapshot technology to solve the data integrity and consistency problem in online backup, which is different from other storage-level snapshot and Open File Solution.展开更多
The periodic window is researched by means of the symbolic dynamics and formal language.Firstly,the proper sampling period is taken and the orbital points of periodic motion are obtained through Poincar6 mapping.Secon...The periodic window is researched by means of the symbolic dynamics and formal language.Firstly,the proper sampling period is taken and the orbital points of periodic motion are obtained through Poincar6 mapping.Secondly,according to the method of symbolic dynamics of one-dimensional discrete mapping,the symbolic sequence describing the periodic orbit is obtained.Finally,based on the symbolic sequence,the corresponding model of minimal finite automation is constructed and the entropy is obtained by calculating the maximal eigenvalue of Stefan matrix.The results show that the orbits in periodic windows can be strictly marked by using the method of symbolic dynamics,thus a foundation for control of switching between target orbits is provided.展开更多
The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is propose...The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is proposed.This combination absorbs the merits of the two algorithms in solutions construction and optimization separately.In order to improve the efficiency of the insertion procedure,a nearest neighbor selection(NNS)mechanism,an insertion local search procedure and a local optimization procedure are specified in detail.And in order to find a balance between good scouting performance and fast convergence rate,an adaptive pheromone updating strategy is proposed in the MTAS.Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW)benchmark instances and the TDVRPTW instances,and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.展开更多
The optical windows used in aircrafts protect their imaging sensors from environmental effects. Considering the imaging performance, flat surfaces are traditionally used in the design of optical windows. For aircrafts...The optical windows used in aircrafts protect their imaging sensors from environmental effects. Considering the imaging performance, flat surfaces are traditionally used in the design of optical windows. For aircrafts operating at high speeds, the optical windows should be relatively aerodynamic, but a flat optical window may introduce unacceptably high drag to the airframes. The linear scanning infrared sensors used in aircrafts with, respectively, a flat window, a spherical window and a toric window in front of the aircraft sensors are designed and compared. Simulation results show that the optical design using a toric surface has the integrated advantages of field of regard, aerodynamic drag, narcissus effect, and imaging performance, so the optical window with a toric surface is demonstrated to be suited for this application.展开更多
A fusion algorithm is proposed to enhance the search speed of an ant colony system(ACS)for the global path planning and overcome the challenges of the local path planning in an unmanned aerial vehicle(UAV).The ACS sea...A fusion algorithm is proposed to enhance the search speed of an ant colony system(ACS)for the global path planning and overcome the challenges of the local path planning in an unmanned aerial vehicle(UAV).The ACS search efficiency is enhanced by adopting a 16-direction 24-neighborhood search way,a safety grid search way,and an elite hybrid strategy to accelerate global convergence.Quadratic planning is performed using the moving average(MA)method.The fusion algorithm incorporates a dynamic window approach(DWA)to deal with the local path planning,sets a retracement mechanism,and adjusts the evaluation function accordingly.Experimental results in two environments demonstrate that the improved ant colony system(IACS)achieves superior planning efficiency.Additionally,the optimized dynamic window approach(ODWA)demonstrates its ability to handle multiple dynamic situations.Overall,the fusion optimization algorithm can accomplish the mixed path planning effectively.展开更多
Principal component analysis(PCA)has been already employed for fault detection of air conditioning systems.The sliding window,which is composed of some parameters satisfying with thermal load balance,can select the ta...Principal component analysis(PCA)has been already employed for fault detection of air conditioning systems.The sliding window,which is composed of some parameters satisfying with thermal load balance,can select the target historical fault-free reference data as the template which is similar to the current snapshot data.The size of sliding window is usually given according to empirical values,while the influence of different sizes of sliding windows on fault detection of an air conditioning system is not further studied.The air conditioning system is a dynamic response process,and the operating parameters change with the change of the load,while the response of the controller is delayed.In a variable air volume(VAV)air conditioning system controlled by the total air volume method,in order to ensure sufficient response time,30 data points are selected first,and then their multiples are selected.Three different sizes of sliding windows with 30,60 and 90 data points are applied to compare the fault detection effect in this paper.The results show that if the size of the sliding window is 60 data points,the average fault-free detection ratio is 80.17%in fault-free testing days,and the average fault detection ratio is 88.47%in faulty testing days.展开更多
This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time ...This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time division duplex(TDD). The system makes use of the same setup as has been used in previous studies of SCFD, but unlike these previous systems, the new system uses water-filling to maximize the spectral efficiency of the uplink channel. The concept of a free window is introduced to the duplex model for measuring, intuitively, the effective bandwidth of the bi-directional communication. The capacity gain is calculated and numerical results show the advantage of the proposed system over that of conventional TDD.展开更多
基金funded on the one hand by Agence de l'Innovation de Défense(AID)grant reference number 2021650044on the other hand by Ecole Centrale de Nantes。
文摘Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.
文摘This research explores the design and implementation of an AI-driven Single Window system for international trade,aimed at enhancing data integration,risk assessment,and decision-making processes.The study focuses on developing a modular,scalable architec-ture that integrates various AI technologies,including machine learning and natural lan-guage processing(NLP),to address inefficiencies in existing systems.The proposed system demonstrates improvements in customs clearance efficiency,risk detection accuracy,and supply chain management.Through detailed case studies,the effectiveness of the AI-driven Single Window system is evaluated,highlighting its impact on port management,interna-tional logistics,and overall trade facilitation.The findings suggest that the integration of AI into Single Window systems can lead to significant advancements in trade efficiency,transparency,and stakeholder collaboration.
文摘This paper explores the role of Artificial Intelligence(AI)in enhancing trade facilitation through its integration with Single Window Systems(SWS).It investigates how AI tech-nologies such as machine learning,natural language processing,and predictive analytics can improve the efficiency and effectiveness of trade processes.Case studies of Singapore and Australia are analyzed to highlight successful AI applications and key lessons learned.The study discusses the benefits,including increased efficiency,reduced costs,enhanced accuracy,and improved user experience,alongside the challenges posed by technical com-plexities,legal and ethical considerations,and resistance to change.The paper also pro-vides policy implications and recommendations for governments,international organiza-tions,and private sector stakeholders.Future research directions emphasize emerging AI technologies like AI-driven blockchain and advanced NLP,and their potential long-term impacts on global trade dynamics.
基金National Natural Science Foundation of China(No.50175064)
文摘Compared to fixed virtual window algorithm(FVWA),the dynamic virtual window algorithm(DVWA)determines the length of each virtual container according to the sizes of goods of each order,which saves space of virtual containers and improves the picking efficiency.However,the interval of consecutive goods caused by dispensers on conveyor can not be eliminated by DVWA,which limits a further improvement of picking efficiency.In order to solve this problem,a compressible virtual window algorithm(CVWA)is presented.It not only inherits the merit of DVWA but also compresses the length of virtual containers without congestion of order accumulation by advancing the beginning time of order picking and reasonably coordinating the pace of order accumulation.The simulation result proves that the picking efficiency of automated sorting system is greatly improved by CVWA.
基金Supported by the National Natural Science Foun-dation of China (60473023) National Innovation Foundation forSmall Technology Based Firms(04C26214201280)
文摘This paper describes a method for building hot snapshot copy based on windows-file system （HSCF）. The architecture and running mechanism of HSCF are discussed after giving a comparison with other on-line backup tecbnology. HSCF, based on a file system filter driver, protects computer data and ensures their integrity and consistency with following three steps： access to open files, synchronization and copy on-write. Its strategies for improving system performance are analyzed including priority setting, incremental snapshot and load balance. HSCF is a new kind of snapshot technology to solve the data integrity and consistency problem in online backup, which is different from other storage-level snapshot and Open File Solution.
基金This project is supported by National Natural Science Foundation of China(No.50075070).
文摘The periodic window is researched by means of the symbolic dynamics and formal language.Firstly,the proper sampling period is taken and the orbital points of periodic motion are obtained through Poincar6 mapping.Secondly,according to the method of symbolic dynamics of one-dimensional discrete mapping,the symbolic sequence describing the periodic orbit is obtained.Finally,based on the symbolic sequence,the corresponding model of minimal finite automation is constructed and the entropy is obtained by calculating the maximal eigenvalue of Stefan matrix.The results show that the orbits in periodic windows can be strictly marked by using the method of symbolic dynamics,thus a foundation for control of switching between target orbits is provided.
文摘The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is proposed.This combination absorbs the merits of the two algorithms in solutions construction and optimization separately.In order to improve the efficiency of the insertion procedure,a nearest neighbor selection(NNS)mechanism,an insertion local search procedure and a local optimization procedure are specified in detail.And in order to find a balance between good scouting performance and fast convergence rate,an adaptive pheromone updating strategy is proposed in the MTAS.Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW)benchmark instances and the TDVRPTW instances,and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.
文摘The optical windows used in aircrafts protect their imaging sensors from environmental effects. Considering the imaging performance, flat surfaces are traditionally used in the design of optical windows. For aircrafts operating at high speeds, the optical windows should be relatively aerodynamic, but a flat optical window may introduce unacceptably high drag to the airframes. The linear scanning infrared sensors used in aircrafts with, respectively, a flat window, a spherical window and a toric window in front of the aircraft sensors are designed and compared. Simulation results show that the optical design using a toric surface has the integrated advantages of field of regard, aerodynamic drag, narcissus effect, and imaging performance, so the optical window with a toric surface is demonstrated to be suited for this application.
基金National Natural Science Foundation of China(No.62241503)Natural Science Foundation of Shanghai,China(No.22ZR1401400)。
文摘A fusion algorithm is proposed to enhance the search speed of an ant colony system(ACS)for the global path planning and overcome the challenges of the local path planning in an unmanned aerial vehicle(UAV).The ACS search efficiency is enhanced by adopting a 16-direction 24-neighborhood search way,a safety grid search way,and an elite hybrid strategy to accelerate global convergence.Quadratic planning is performed using the moving average(MA)method.The fusion algorithm incorporates a dynamic window approach(DWA)to deal with the local path planning,sets a retracement mechanism,and adjusts the evaluation function accordingly.Experimental results in two environments demonstrate that the improved ant colony system(IACS)achieves superior planning efficiency.Additionally,the optimized dynamic window approach(ODWA)demonstrates its ability to handle multiple dynamic situations.Overall,the fusion optimization algorithm can accomplish the mixed path planning effectively.
基金Fundamental Research Funds for the Central Universities of Ministry of Education of China。
文摘Principal component analysis(PCA)has been already employed for fault detection of air conditioning systems.The sliding window,which is composed of some parameters satisfying with thermal load balance,can select the target historical fault-free reference data as the template which is similar to the current snapshot data.The size of sliding window is usually given according to empirical values,while the influence of different sizes of sliding windows on fault detection of an air conditioning system is not further studied.The air conditioning system is a dynamic response process,and the operating parameters change with the change of the load,while the response of the controller is delayed.In a variable air volume(VAV)air conditioning system controlled by the total air volume method,in order to ensure sufficient response time,30 data points are selected first,and then their multiples are selected.Three different sizes of sliding windows with 30,60 and 90 data points are applied to compare the fault detection effect in this paper.The results show that if the size of the sliding window is 60 data points,the average fault-free detection ratio is 80.17%in fault-free testing days,and the average fault detection ratio is 88.47%in faulty testing days.
基金supported by the HongKong, Macao and Taiwan Science & Technology Cooperation Program of China (Grant no. 2015DFT10170)the Beijing Higher Education Young Elite Teacher Project
文摘This paper studies the capacity issues of a wireless communication system that implements single channel full duplex(SCFD) communication at the base station(BS), thereby the mobile stations share the channel via time division duplex(TDD). The system makes use of the same setup as has been used in previous studies of SCFD, but unlike these previous systems, the new system uses water-filling to maximize the spectral efficiency of the uplink channel. The concept of a free window is introduced to the duplex model for measuring, intuitively, the effective bandwidth of the bi-directional communication. The capacity gain is calculated and numerical results show the advantage of the proposed system over that of conventional TDD.
