P2P systems are categorized into tree-based and mesh-based systems according to their topologies. Mesh-based systems are considered more suitable for large-scale lnternet applications, but require optimization on late...P2P systems are categorized into tree-based and mesh-based systems according to their topologies. Mesh-based systems are considered more suitable for large-scale lnternet applications, but require optimization on latency issue. This paper proposes a content subscribing mechanism （CSM） to eliminate unnecessary time delays during data relaying. A node can send content data to its neighbors as soon as it receives the data segment. No additional time is taken during the interactive stages prior to data segment transmission of streaming content. CSM consists of three steps. First, every node records its historical segments latency, and adopts gamma distribution, which possesses powerful expression ability, to express latency statistics. Second, a node predicts subscribing success ratio of every neighbor by comparing the gamma distribution parameters of the node and its neighbors before selecting a neighbor node to subscribe a data segment. The above steps would not increase latency as they are executed before the data segments are ready at the neighbor nodes. Finally, the node, which was subscribed to, sends the subscribed data segment to the subscriber immediately when it has the data segment. Experiments show that CSM significantly reduces the content data transmission latency.展开更多
Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society f...Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society for Rock Mechanics and Engineering and Wuhan University.展开更多
To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to ac...To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.展开更多
Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The ...Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The relationship between the interfacial characteristics and the dynamic compressive behavior was investigated.The results indicate that the interface characteristics of composites include interfacial diffusion and interfacial reaction,and the interfacial shear strength increases when the interfacial reaction is serious.The dynamic plastic performance are improved obviously if the suitable interface reaction occurs.The failure occurs by shear and the fibers split longitudinally if there is no interface reaction or a little reaction;in contrast,holistic failure occurs if there is too much interface reaction.展开更多
基金the National Natural Science Foundation of China (Nos. 60533090 and 60525108)the National Basic research Program (973) of China (No. 2002CB312101)+2 种基金the China-US Million Book Digital Library Project (www.cadal.zju.edu.cn)the Science and Technology Project of Zhejiang Province (Nos. 2005C13032 and 2005C11001-05)the Research Project of Education Department of Zhejiang Province (No. 20061352), China
文摘P2P systems are categorized into tree-based and mesh-based systems according to their topologies. Mesh-based systems are considered more suitable for large-scale lnternet applications, but require optimization on latency issue. This paper proposes a content subscribing mechanism （CSM） to eliminate unnecessary time delays during data relaying. A node can send content data to its neighbors as soon as it receives the data segment. No additional time is taken during the interactive stages prior to data segment transmission of streaming content. CSM consists of three steps. First, every node records its historical segments latency, and adopts gamma distribution, which possesses powerful expression ability, to express latency statistics. Second, a node predicts subscribing success ratio of every neighbor by comparing the gamma distribution parameters of the node and its neighbors before selecting a neighbor node to subscribe a data segment. The above steps would not increase latency as they are executed before the data segments are ready at the neighbor nodes. Finally, the node, which was subscribed to, sends the subscribed data segment to the subscriber immediately when it has the data segment. Experiments show that CSM significantly reduces the content data transmission latency.
文摘Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society for Rock Mechanics and Engineering and Wuhan University.
基金Supported by the National Natural Science Foundation of China Youth Fund Project(52005221)"the 13th Five-Year"National Key Research and Development Program:High-speed Planting Technology and Equipment Research and Development(2017YFD0700800)。
文摘To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.
基金Project(2005K06-G2)supported by the New Century Excellent Person Supporting Project of Ministry of Education of China
文摘Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The relationship between the interfacial characteristics and the dynamic compressive behavior was investigated.The results indicate that the interface characteristics of composites include interfacial diffusion and interfacial reaction,and the interfacial shear strength increases when the interfacial reaction is serious.The dynamic plastic performance are improved obviously if the suitable interface reaction occurs.The failure occurs by shear and the fibers split longitudinally if there is no interface reaction or a little reaction;in contrast,holistic failure occurs if there is too much interface reaction.
