Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud fede...Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud federation. Data transmissions required for inter-cloud federation in the complex inter-cloud networking system are often point-to-multi points, which calls for a more effective and efficient multicast routing algorithm in complex networking systems. In this paper, we investigate the multicast routing problem in the inter-cloud context with K constraints where K ≥ 2. Unlike most of existing algorithms that are too complex to be applied in practical scenarios, a novel and fast algorithm for establishing multicast routing tree for interclouds is proposed. The proposed algorithm leverages an entropybased process to aggregate all weights into a comprehensive metric, and then uses it to search a multicast tree(MT) on the basis of the shortest path tree(SPT). We conduct complexity analysis and extensive simulations for the proposed algorithm from the approximation perspective. Both analytical and experimental results demonstrate that the algorithm is more efficient than a representative multi-constrained multicast routing algorithm in terms of both speed and accuracy, and thus we believe that the proposed algorithm is applicable to the inter-cloud environment.展开更多
A contour-parallel offset （CPO） tool-path linking algorithm is derived without toolretractions and with the largest practicability. The concept of ＂tool-path loop tree＂ （TPL-tree） providing the information on th...A contour-parallel offset （CPO） tool-path linking algorithm is derived without toolretractions and with the largest practicability. The concept of ＂tool-path loop tree＂ （TPL-tree） providing the information on the parent/child relationships among the tool-path loops （TPLs） is presented. The direction, tool-path loop, leaf/branch, layer number, and the corresponding points of the TPL-tree are introduced. By defining TPL as a vector, and by traveling throughout the tree, a CPO tool-path without tool-retractions can be derived.展开更多
A vertex subversion strategy of a graph G=(V,E) is a set of vertices S V(G) whose closed neighborhood is deleted from G . The survival subgraph is denoted by G/S . We call S a cut-strategy of G if G/S is disconnected,...A vertex subversion strategy of a graph G=(V,E) is a set of vertices S V(G) whose closed neighborhood is deleted from G . The survival subgraph is denoted by G/S . We call S a cut-strategy of G if G/S is disconnected, or is a clique, or is φ . The vertex-neighbor scattering number of G is defined to be VNS(G)=max{ω(G/S)-|S|} , where S is any cut-strategy of G , and ω(G/G) is the number of the components of G/S . It has been proved that the computing problem of this parameter is NP–complete, so we discuss the properties of vertex-neighbor-scattering number of trees in this paper.展开更多
For motion planning of concrete pump truck( CPT) with end-effector's hosepipe path, this paper sets up the mathematic model,including definition of its motion planning,description of its state in C space( configur...For motion planning of concrete pump truck( CPT) with end-effector's hosepipe path, this paper sets up the mathematic model,including definition of its motion planning,description of its state in C space( configuration space) and its path length. An advanced rapidly-exploring random trees( RRT) algorithm is proposed, in which each tracing point dispersed from the end hosepipe path can map multi-states of CPT so as to make variety of motion path of CPT. For increasing search efficiency and motion path quality,this algorithm generates any random states of CPT in certain probability to trend to the initial state or target state mapped with the end hosepipe path,and to have the least cost between this random state and its parent state. A typical case and two special cases are analyzed in which the end hosepipe paths are reciprocating linear trajectory and planar or spatial sine curves respectively. Their results verify the feasibility and validity of the proposed algorithm.展开更多
Let G be a (p,q) graph. An injective map f:V(G)→﹛±1,±2,...±p﹜is called a pair sum labeling if the induced edge function, fe:E(G)→Z-﹛0﹜defined by fe(uv)=f(u)+f(v) is one-one and fe(E(G)) is either ...Let G be a (p,q) graph. An injective map f:V(G)→﹛±1,±2,...±p﹜is called a pair sum labeling if the induced edge function, fe:E(G)→Z-﹛0﹜defined by fe(uv)=f(u)+f(v) is one-one and fe(E(G)) is either of the form {±k1,±k2,...,±kq/2} or {±k1,±k2,...,±kq-1/2}∪{kq+1/2} according as q is even or odd. A graph with a pair sum labeling is called a pair sum graph. In this paper we investigate the pair sum labeling behavior of some trees which are derived from stars and bistars. Finally, we show that all trees of order nine are pair sum graphs.展开更多
基金supported by the National Natural Science Foundation of China(61309031)
文摘Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud federation. Data transmissions required for inter-cloud federation in the complex inter-cloud networking system are often point-to-multi points, which calls for a more effective and efficient multicast routing algorithm in complex networking systems. In this paper, we investigate the multicast routing problem in the inter-cloud context with K constraints where K ≥ 2. Unlike most of existing algorithms that are too complex to be applied in practical scenarios, a novel and fast algorithm for establishing multicast routing tree for interclouds is proposed. The proposed algorithm leverages an entropybased process to aggregate all weights into a comprehensive metric, and then uses it to search a multicast tree(MT) on the basis of the shortest path tree(SPT). We conduct complexity analysis and extensive simulations for the proposed algorithm from the approximation perspective. Both analytical and experimental results demonstrate that the algorithm is more efficient than a representative multi-constrained multicast routing algorithm in terms of both speed and accuracy, and thus we believe that the proposed algorithm is applicable to the inter-cloud environment.
文摘A contour-parallel offset （CPO） tool-path linking algorithm is derived without toolretractions and with the largest practicability. The concept of ＂tool-path loop tree＂ （TPL-tree） providing the information on the parent/child relationships among the tool-path loops （TPLs） is presented. The direction, tool-path loop, leaf/branch, layer number, and the corresponding points of the TPL-tree are introduced. By defining TPL as a vector, and by traveling throughout the tree, a CPO tool-path without tool-retractions can be derived.
文摘A vertex subversion strategy of a graph G=(V,E) is a set of vertices S V(G) whose closed neighborhood is deleted from G . The survival subgraph is denoted by G/S . We call S a cut-strategy of G if G/S is disconnected, or is a clique, or is φ . The vertex-neighbor scattering number of G is defined to be VNS(G)=max{ω(G/S)-|S|} , where S is any cut-strategy of G , and ω(G/G) is the number of the components of G/S . It has been proved that the computing problem of this parameter is NP–complete, so we discuss the properties of vertex-neighbor-scattering number of trees in this paper.
基金Nature Science Foundation of Liaoning Province,China(No.201102025)Dalian Science and Technology Plan Project,China(Nos.2012A17GX122,2013A16GX111)Fundamental Research Funds for the Central Universities,China(No.DUT14ZD221)
文摘For motion planning of concrete pump truck( CPT) with end-effector's hosepipe path, this paper sets up the mathematic model,including definition of its motion planning,description of its state in C space( configuration space) and its path length. An advanced rapidly-exploring random trees( RRT) algorithm is proposed, in which each tracing point dispersed from the end hosepipe path can map multi-states of CPT so as to make variety of motion path of CPT. For increasing search efficiency and motion path quality,this algorithm generates any random states of CPT in certain probability to trend to the initial state or target state mapped with the end hosepipe path,and to have the least cost between this random state and its parent state. A typical case and two special cases are analyzed in which the end hosepipe paths are reciprocating linear trajectory and planar or spatial sine curves respectively. Their results verify the feasibility and validity of the proposed algorithm.
文摘Let G be a (p,q) graph. An injective map f:V(G)→﹛±1,±2,...±p﹜is called a pair sum labeling if the induced edge function, fe:E(G)→Z-﹛0﹜defined by fe(uv)=f(u)+f(v) is one-one and fe(E(G)) is either of the form {±k1,±k2,...,±kq/2} or {±k1,±k2,...,±kq-1/2}∪{kq+1/2} according as q is even or odd. A graph with a pair sum labeling is called a pair sum graph. In this paper we investigate the pair sum labeling behavior of some trees which are derived from stars and bistars. Finally, we show that all trees of order nine are pair sum graphs.
