Contacts between two general blocks are the fundamental problem for discontinuous analysis. There are different contact points in different block positions, and there may have infinite contact point pairs in the same ...Contacts between two general blocks are the fundamental problem for discontinuous analysis. There are different contact points in different block positions, and there may have infinite contact point pairs in the same block position. In this paper, a new concept of an entrance block for solving the contacts between two general blocks is introduced. The boundary of an entrance block is a contact cover system. Contact covers may consist of contact vectors, edges, angles or polygons. Each contact cover defines a contact point and all closed-contact points define the movements, rotations and deformations of all blocks as in real cases. Given a reference point, the concept of entrance block simplifies the contact computation in the following ways.(1) The shortest distance between two blocks can be computed by the shortest distance between the reference point and the surface of the entrance block.(2) As the reference point outside the entrance block moves onto the surface of entrance block, the first entrance takes place. This first entrance point on the entrance block surface defines the contact points and related contact locations.(3) If the reference point is already inside the entrance block, it will exit the entrance block along the shortest path. The corresponding shortest exit point on the entrance block surface defines the contact points and related contact locations. All blocks and angles here are defined by inequality equations. Algebraic operations on blocks and angles are described here. Since the blocks and angles are point sets with infinite points, the geometric computations are difficult, and therefore the geometric computations are performed by related algebraic operations.展开更多
Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the applicat...Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still exist.Due to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of terminals.Considering the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy consumption.However,the resulting optimization problem is originally nonconvex and thus,difficult to solve optimally.To tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex subproblems.Furthermore,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser terminals.Simulation results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.展开更多
The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calc...The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calculated by carbon emission flow theory.However,the calculation procedure is time-consuming,especially for a country with 500-1000 thousand nodes,making it challenging to obtain nationwide carbon emis-sions intensity precisely.Additionally,the calculation procedure requires to gather all the grid data with high classified levels from different power grid companies,which can prevent data sharing and cooperation among different companies.This paper proposes a distributed computing algorithm for indirect carbon emission that can reduce the time consumption and provide privacy protection.The core idea is to utilize the sparsity of the nodes’flow matrix of the nationwide grid to partition the computing procedure into parallel sub-procedures exe-cuted in multiple terminals.The flow and structure data of the regional grid are transformed irreversibly for pri-vacy protection,when transmitted between terminals.A 1-master-and-N-slave layout is adopted to verify the method.This algorithm is suitable for large grid compa-nies with headquarter and branches in provinces,such as the State Grid Corporation of China.展开更多
分布式能源的广泛发展使其成为电力市场的考虑重点,而传统的数据交互平台无法满足大规模分布式能源交易高效灵活、安全可靠的需求。为解决高信息处理复杂度与安全快速交易需求之间的矛盾,文中提出基于云边协同和区块链的分布式能源交易...分布式能源的广泛发展使其成为电力市场的考虑重点,而传统的数据交互平台无法满足大规模分布式能源交易高效灵活、安全可靠的需求。为解决高信息处理复杂度与安全快速交易需求之间的矛盾,文中提出基于云边协同和区块链的分布式能源交易系统架构和整体设计方案。首先设计了云计算与边缘计算协同并结合两层区块链的系统架构,利用区块链技术实现交易去中心化,提高了交易的自主高效性,利用云边协同提升海量数据的处理能力和交易系统的扩展能力。然后基于双向竞价和预测补偿设计了分布式能源的交易机制,进一步对区块链的核心共识算法进行分析,并采用改进委托权益证明(delegated proof of stake,DPoS)作为交易系统的高效率、高可靠共识算法,实现大规模分布式能源的高效可靠交易,促进分布式能源参与电网调节,提高电网稳定运行水平。最后通过应用实例验证了所提系统对大规模分布式能源交易的适应性和优越性。展开更多
This study is a digital form-finding and manual fabrication experiment in woven architectural design,with one traditional weaving style,Kagome,used to scale the craft up into an architectural-scale bamboo woven artifa...This study is a digital form-finding and manual fabrication experiment in woven architectural design,with one traditional weaving style,Kagome,used to scale the craft up into an architectural-scale bamboo woven artifact.Kagome is a trihexagonal pattern employed in traditional bamboo basketry as a triaxial weaving system,resulting in an object with a self-bracing capacity without the use of fasteners owing to its interlacing lattices.Although existing studies and tools have addressed triaxial weaving design and representation,the current consideration of the advantages of weaving with bamboo is insufficient.To address this research gap,this study develops a computational design method based on studies on bamboo basketry.This allows for the representation and exploration of design geometries using combinations of regular triangular meshes for the fabrication of Kagome woven bamboo artifacts.A full-scale mock-up was fabricated to evaluate the effectiveness of the method.The mock-up demonstrated the self-bracing properties of Kagome,but there were discrepancies between the mock-up and the design.Factors affecting bamboo weaving on an architectural scale have been identified within this study to inform future research on woven bamboo structures.展开更多
The geometry relation and the contact point-pairs detection between two three dimensional(3D) objects with arbitrary shapes are essential problems involved in discontinuous computation and computational geometry. This...The geometry relation and the contact point-pairs detection between two three dimensional(3D) objects with arbitrary shapes are essential problems involved in discontinuous computation and computational geometry. This paper reported a geometry relation judgment and contact searching algorithm based on Contact Theory. A contact cover search algorithm is proposed to find all the possible contact cover between two blocks. Two blocks can come to contact only on these covers. Each contact cover can define a possible contact point-pair between two blocks. Data structure and flow chart are provided, as well as some examples in details.Contact problems involving concave blocks or parallel planes are considered to be very difficult in past and are solved by this algorithm. The proposed algorithm is compacted and applicable to the discontinuous computation, such as robotic control, rock mass stability, dam stability etc. A 3D cutting and block searching algorithm is also proposed in this study and used to search the outer boundary of the 3D entrance block when 3D concave blocks are encountered. The 3D cutting and block searching algorithm can be also used to form the block system for jointed rock.展开更多
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2014CB047100)
文摘Contacts between two general blocks are the fundamental problem for discontinuous analysis. There are different contact points in different block positions, and there may have infinite contact point pairs in the same block position. In this paper, a new concept of an entrance block for solving the contacts between two general blocks is introduced. The boundary of an entrance block is a contact cover system. Contact covers may consist of contact vectors, edges, angles or polygons. Each contact cover defines a contact point and all closed-contact points define the movements, rotations and deformations of all blocks as in real cases. Given a reference point, the concept of entrance block simplifies the contact computation in the following ways.(1) The shortest distance between two blocks can be computed by the shortest distance between the reference point and the surface of the entrance block.(2) As the reference point outside the entrance block moves onto the surface of entrance block, the first entrance takes place. This first entrance point on the entrance block surface defines the contact points and related contact locations.(3) If the reference point is already inside the entrance block, it will exit the entrance block along the shortest path. The corresponding shortest exit point on the entrance block surface defines the contact points and related contact locations. All blocks and angles here are defined by inequality equations. Algebraic operations on blocks and angles are described here. Since the blocks and angles are point sets with infinite points, the geometric computations are difficult, and therefore the geometric computations are performed by related algebraic operations.
基金supported by the Jiangsu Provincial Key Research and Development Program(No.BE2020084-4)the National Natural Science Foundation of China(No.92067201)+2 种基金the National Natural Science Foundation of China(61871446)the Open Research Fund of Jiangsu Key Laboratory of Wireless Communications(710020017002)the Natural Science Foundation of Nanjing University of Posts and telecommunications(NY220047).
文摘Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still exist.Due to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of terminals.Considering the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy consumption.However,the resulting optimization problem is originally nonconvex and thus,difficult to solve optimally.To tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex subproblems.Furthermore,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser terminals.Simulation results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.
基金supported by the Science and Technol-ogy Project of State Grid Cooperation of China(No.5700-202290184A-1-1-ZN).
文摘The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calculated by carbon emission flow theory.However,the calculation procedure is time-consuming,especially for a country with 500-1000 thousand nodes,making it challenging to obtain nationwide carbon emis-sions intensity precisely.Additionally,the calculation procedure requires to gather all the grid data with high classified levels from different power grid companies,which can prevent data sharing and cooperation among different companies.This paper proposes a distributed computing algorithm for indirect carbon emission that can reduce the time consumption and provide privacy protection.The core idea is to utilize the sparsity of the nodes’flow matrix of the nationwide grid to partition the computing procedure into parallel sub-procedures exe-cuted in multiple terminals.The flow and structure data of the regional grid are transformed irreversibly for pri-vacy protection,when transmitted between terminals.A 1-master-and-N-slave layout is adopted to verify the method.This algorithm is suitable for large grid compa-nies with headquarter and branches in provinces,such as the State Grid Corporation of China.
文摘分布式能源的广泛发展使其成为电力市场的考虑重点,而传统的数据交互平台无法满足大规模分布式能源交易高效灵活、安全可靠的需求。为解决高信息处理复杂度与安全快速交易需求之间的矛盾,文中提出基于云边协同和区块链的分布式能源交易系统架构和整体设计方案。首先设计了云计算与边缘计算协同并结合两层区块链的系统架构,利用区块链技术实现交易去中心化,提高了交易的自主高效性,利用云边协同提升海量数据的处理能力和交易系统的扩展能力。然后基于双向竞价和预测补偿设计了分布式能源的交易机制,进一步对区块链的核心共识算法进行分析,并采用改进委托权益证明(delegated proof of stake,DPoS)作为交易系统的高效率、高可靠共识算法,实现大规模分布式能源的高效可靠交易,促进分布式能源参与电网调节,提高电网稳定运行水平。最后通过应用实例验证了所提系统对大规模分布式能源交易的适应性和优越性。
基金the Start-up Grant from the School of Architecture at The Chinese University of Hong Kong[ARC]partially by the General Research Fund[RGC Ref.No.CUHK 14617122]from the Hong Kong Research Grants Council.
文摘This study is a digital form-finding and manual fabrication experiment in woven architectural design,with one traditional weaving style,Kagome,used to scale the craft up into an architectural-scale bamboo woven artifact.Kagome is a trihexagonal pattern employed in traditional bamboo basketry as a triaxial weaving system,resulting in an object with a self-bracing capacity without the use of fasteners owing to its interlacing lattices.Although existing studies and tools have addressed triaxial weaving design and representation,the current consideration of the advantages of weaving with bamboo is insufficient.To address this research gap,this study develops a computational design method based on studies on bamboo basketry.This allows for the representation and exploration of design geometries using combinations of regular triangular meshes for the fabrication of Kagome woven bamboo artifacts.A full-scale mock-up was fabricated to evaluate the effectiveness of the method.The mock-up demonstrated the self-bracing properties of Kagome,but there were discrepancies between the mock-up and the design.Factors affecting bamboo weaving on an architectural scale have been identified within this study to inform future research on woven bamboo structures.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51479001, 41471052)the China Institute of Water Resources and Hydropower Research Research & Development Support Program(Grant Nos. GE0145B462017, GE0145B692017)
文摘The geometry relation and the contact point-pairs detection between two three dimensional(3D) objects with arbitrary shapes are essential problems involved in discontinuous computation and computational geometry. This paper reported a geometry relation judgment and contact searching algorithm based on Contact Theory. A contact cover search algorithm is proposed to find all the possible contact cover between two blocks. Two blocks can come to contact only on these covers. Each contact cover can define a possible contact point-pair between two blocks. Data structure and flow chart are provided, as well as some examples in details.Contact problems involving concave blocks or parallel planes are considered to be very difficult in past and are solved by this algorithm. The proposed algorithm is compacted and applicable to the discontinuous computation, such as robotic control, rock mass stability, dam stability etc. A 3D cutting and block searching algorithm is also proposed in this study and used to search the outer boundary of the 3D entrance block when 3D concave blocks are encountered. The 3D cutting and block searching algorithm can be also used to form the block system for jointed rock.
