The virtual network embedding/mapping problem is an important issue in network virtualization in Software-Defined Networking(SDN).It is mainly concerned with mapping virtual network requests,which could be a set of SD...The virtual network embedding/mapping problem is an important issue in network virtualization in Software-Defined Networking(SDN).It is mainly concerned with mapping virtual network requests,which could be a set of SDN flows,onto a shared substrate network automatically and efficiently.Previous researches mainly focus on developing heuristic algorithms for general topology virtual network.In practice however,the virtual network is usually generated with specific topology for specific purpose.Thus,it is a challenge to optimize the heuristic algorithms with these topology information.In order to deal with this problem,we propose a topology-cognitive algorithm framework,which is composed of a guiding principle for topology algorithm developing and a compound algorithm.The compound algorithm is composed of several subalgorithms,which are optimized for specific topologies.We develop star,tree,and ring topology algorithms as examples,other subalgorithms can be easily achieved following the same framework.The simulation results show that the topology-cognitive algorithm framework is effective in developing new topology algorithms,and the developed compound algorithm greatly enhances the performance of the Revenue/Cost(R/C) ratio and the Runtime than traditional heuristic algorithms for multi-topology virtual network embedding problem.展开更多
The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network t...The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.展开更多
Advanced electromagnetic(EM)wave absorbing materials with strong absorption and broad bandwidth are important for military stealth and elimination of microwave pollution in consumers’electronics.Metal organic framewo...Advanced electromagnetic(EM)wave absorbing materials with strong absorption and broad bandwidth are important for military stealth and elimination of microwave pollution in consumers’electronics.Metal organic framework(MOF)-derived metal/carbon hybrids with ordered structure are significantly urgent in this field.In this contribution,we presented a design strategy of hollow cage-like or solid box-like magnetic/dielectric Fe/Co/C and dielectric Fe/Mn/C EM wave absorbing nanomaterials via pyrolyzing Prussian blue’s analogs with controllable topology and phase composition.The solid box-like Fe/Co/C and hollow cage-like Fe/Mn/C showed favorable absorption property with a broad effective absorption bandwidth(EAB)and a low reflection loss(RL).Especially,the EAB of 8.8 GHz at a thickness of 2.5 mm for solid box-like Fe/Co/C nanocomplex prepared at 900℃is a new record for this type of materials.The design and tuning strategy for EM wave absorbers derived from topology-controllable MOF is important for EM functional materials possessing great potential in military stealth and consumers’electronics.展开更多
Three 3D manganese-organic frameworks, Mn2(BPTC)(DMF)2(H2O)·DMF·3H2O(1), Mn2(BPTC)(bipy)(DMF)·DMF·H2O(2), and Mn2(BPTC)(phen)(DMF)·EtOH(3), have been solvothermally synthesized using 3,3′,5,5...Three 3D manganese-organic frameworks, Mn2(BPTC)(DMF)2(H2O)·DMF·3H2O(1), Mn2(BPTC)(bipy)(DMF)·DMF·H2O(2), and Mn2(BPTC)(phen)(DMF)·EtOH(3), have been solvothermally synthesized using 3,3′,5,5′-biphenyltetracarboxylic acid(H4BPTC). All complexes are characterized by PXRD, EA, IR and TG. The results show that they all bear the PtS topology with(42.84)(42.84) for the vertex symbols of the planar and tetrahedral nodes, in which the BPTC ligand is considered as a square-planar 4-connected linker, and every binuclear SBU connected to the four BPTC ligands is simplified into tetrahedral 4-connected nodes. Because the three coordination sites of one metal center of SBU are occupied by the coordinated solvent molecules, complex 1 exhibits low stability. After substituting 2,2′-bipy or 1,10-phen for two coordinated solvent molecules, complexes 2 and 3 display evidently higher structure stability. The magnetism property of complex 2 is also discussed in detail.展开更多
文摘The virtual network embedding/mapping problem is an important issue in network virtualization in Software-Defined Networking(SDN).It is mainly concerned with mapping virtual network requests,which could be a set of SDN flows,onto a shared substrate network automatically and efficiently.Previous researches mainly focus on developing heuristic algorithms for general topology virtual network.In practice however,the virtual network is usually generated with specific topology for specific purpose.Thus,it is a challenge to optimize the heuristic algorithms with these topology information.In order to deal with this problem,we propose a topology-cognitive algorithm framework,which is composed of a guiding principle for topology algorithm developing and a compound algorithm.The compound algorithm is composed of several subalgorithms,which are optimized for specific topologies.We develop star,tree,and ring topology algorithms as examples,other subalgorithms can be easily achieved following the same framework.The simulation results show that the topology-cognitive algorithm framework is effective in developing new topology algorithms,and the developed compound algorithm greatly enhances the performance of the Revenue/Cost(R/C) ratio and the Runtime than traditional heuristic algorithms for multi-topology virtual network embedding problem.
基金supported by the National High Technology Research and Development Program of China No.2014AA01A701Nature and Science Foundation of China under Grants No.61471068,61421061+2 种基金Beijing Nova Programme No.Z131101000413030International Collaboration Project No.2015DFT10160National Major Project No.2016ZX03001009-003
文摘The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.
基金This work was financially supported by the National Natural Science Foundation of China(21875190)Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars,the Natural Science Basic Research Plan in Shaanxi Province of Distinguished Young Scholar(2018JC-008)China Postdoctoral Science Foundation(2018M643724).
文摘Advanced electromagnetic(EM)wave absorbing materials with strong absorption and broad bandwidth are important for military stealth and elimination of microwave pollution in consumers’electronics.Metal organic framework(MOF)-derived metal/carbon hybrids with ordered structure are significantly urgent in this field.In this contribution,we presented a design strategy of hollow cage-like or solid box-like magnetic/dielectric Fe/Co/C and dielectric Fe/Mn/C EM wave absorbing nanomaterials via pyrolyzing Prussian blue’s analogs with controllable topology and phase composition.The solid box-like Fe/Co/C and hollow cage-like Fe/Mn/C showed favorable absorption property with a broad effective absorption bandwidth(EAB)and a low reflection loss(RL).Especially,the EAB of 8.8 GHz at a thickness of 2.5 mm for solid box-like Fe/Co/C nanocomplex prepared at 900℃is a new record for this type of materials.The design and tuning strategy for EM wave absorbers derived from topology-controllable MOF is important for EM functional materials possessing great potential in military stealth and consumers’electronics.
基金supported by the National Natural Science Foundation of China(21271117,21201179)the Special Fund for Postdoctoral Innovation Program of the Shandong Province(201202040)+4 种基金the China Postdoctoral Science Foundation(2012M 510106)a project of the Shandong Province Higher Educational Science and Technology Program(J06A55)the Shandong Provincial Natural Science Foundation(ZR2010BL011)the Shandong Natural Science Fund for Distinguished Young Scholars(BS2012CL038)the Fundamental Research Funds for the Central Universities(12CX04092A,13CX05015A)
文摘Three 3D manganese-organic frameworks, Mn2(BPTC)(DMF)2(H2O)·DMF·3H2O(1), Mn2(BPTC)(bipy)(DMF)·DMF·H2O(2), and Mn2(BPTC)(phen)(DMF)·EtOH(3), have been solvothermally synthesized using 3,3′,5,5′-biphenyltetracarboxylic acid(H4BPTC). All complexes are characterized by PXRD, EA, IR and TG. The results show that they all bear the PtS topology with(42.84)(42.84) for the vertex symbols of the planar and tetrahedral nodes, in which the BPTC ligand is considered as a square-planar 4-connected linker, and every binuclear SBU connected to the four BPTC ligands is simplified into tetrahedral 4-connected nodes. Because the three coordination sites of one metal center of SBU are occupied by the coordinated solvent molecules, complex 1 exhibits low stability. After substituting 2,2′-bipy or 1,10-phen for two coordinated solvent molecules, complexes 2 and 3 display evidently higher structure stability. The magnetism property of complex 2 is also discussed in detail.
