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
计算能力弱、存储容量小是普通物联网节点的典型特征,复杂的部署环境和不稳定的无线链路又会导致物联网网络状态频繁变化.所以,物联网中固定的传输路径无法提供高效的感知及数据传输服务.例如典型的树型路由结构中,靠近树根的节点要提...计算能力弱、存储容量小是普通物联网节点的典型特征,复杂的部署环境和不稳定的无线链路又会导致物联网网络状态频繁变化.所以,物联网中固定的传输路径无法提供高效的感知及数据传输服务.例如典型的树型路由结构中,靠近树根的节点要提供的传输任务较重,能量消耗更快,会导致整个网络部署周期变短.本文提出了一种路径可实时定义的物联网传输模型(IoT Transmission Model with Real-time Path Definition,ITRP),物联子网中所有节点将邻接关系上报给网关设备,由性能占优的有源供电网关设备来定义网络的实时路由树.网关向物联子网节点发送报文时会携带转发标签,后续转发节点只需根据标签完成报文传输,并根据上一跳信息建立其到网关的反向传输路径.ITRP模型可围绕特定的网络服务目标(节能、传输安全、带宽保障等)收集相关网络状态信息,并周期性调整路由拓扑,实现物联网传输服务的优化.实验面向能量均衡目标展开,经过10个信息采集周期,ITRP模型相对确定性路由模型能量最低节点的能耗比为44%~86%,相对自适应多径传输模型能量最低节点的能耗比为63%~86%;而且,ITRP模型只需较小的标签代价,实验环境中报文的平均标签长度不超过5比特.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.
文摘计算能力弱、存储容量小是普通物联网节点的典型特征,复杂的部署环境和不稳定的无线链路又会导致物联网网络状态频繁变化.所以,物联网中固定的传输路径无法提供高效的感知及数据传输服务.例如典型的树型路由结构中,靠近树根的节点要提供的传输任务较重,能量消耗更快,会导致整个网络部署周期变短.本文提出了一种路径可实时定义的物联网传输模型(IoT Transmission Model with Real-time Path Definition,ITRP),物联子网中所有节点将邻接关系上报给网关设备,由性能占优的有源供电网关设备来定义网络的实时路由树.网关向物联子网节点发送报文时会携带转发标签,后续转发节点只需根据标签完成报文传输,并根据上一跳信息建立其到网关的反向传输路径.ITRP模型可围绕特定的网络服务目标(节能、传输安全、带宽保障等)收集相关网络状态信息,并周期性调整路由拓扑,实现物联网传输服务的优化.实验面向能量均衡目标展开,经过10个信息采集周期,ITRP模型相对确定性路由模型能量最低节点的能耗比为44%~86%,相对自适应多径传输模型能量最低节点的能耗比为63%~86%;而且,ITRP模型只需较小的标签代价,实验环境中报文的平均标签长度不超过5比特.
