A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）...A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）, large （242-332 m^2） and very large （333-550 m^2） gaps, as well as under closed stands were studied eight years after-the gap creation. Soil samples were taken from three depths, 0-10, 10-20 and 20-30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters： Mg^＋2 concentration of 0-10 cm at medium gap size, bulk density of 10-20 cm at very large gap size as well as K^＋ and Ca^＋2 concentrations at 20-30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent （Sp %） at 0-10cm as well as P and Mg^＋2 at 20--30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca^＋2 at depth 0--10 cm and 10-20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.展开更多
To verify if the response by Eucalyptus clones in a single-tree plot is influenced by neighboring plants and to determine the effect of missing and/or dominated plants,seven eucalyptus trials in four Brazilian states ...To verify if the response by Eucalyptus clones in a single-tree plot is influenced by neighboring plants and to determine the effect of missing and/or dominated plants,seven eucalyptus trials in four Brazilian states were analyzed in a randomized complete block design with one plant/plot and 30 replications.Mean annual increment(MAI,m^(3)ha^(-1)per year)was determined for three-year-old clones.The influence of neighboring clones was estimated by a linear regression coefficient between the MAI of each clone/plot and the average of a clonal MAI and its eight neighbors.To determine the effect of missing and/or dominated trees,a correction between the MAI and the area available/plant was applied.Subsequent analysis considered unadjusted and adjusted data for missing and dominated trees.Estimate of accuracy and index of coincidence were used to compare the adjustments.In single-tree plots,clone performances were not influenced by neighboring plants.Experimental accuracy was not increased by any of the adjustments employed and the clone ranking was not altered,and therefore did not justify their use.展开更多
As the cornerstone of future information security,quantum key distribution(QKD)is evolving towards large-scale hybrid discrete-variable/continuous-variable(DV/CV)multi-domain quantum networks.Meanwhile,multicast-orien...As the cornerstone of future information security,quantum key distribution(QKD)is evolving towards large-scale hybrid discrete-variable/continuous-variable(DV/CV)multi-domain quantum networks.Meanwhile,multicast-oriented multi-party key negotiation is attracting increasing attention in quantum networks.However,the efficient key provision for multicast services over hybrid DV/CV multi-domain quantum networks remains challenging,due to the limited probability of service success and the inefficient utilization of key resources.Targeting these challenges,this study proposes two key-resource-aware multicast-oriented key provision strategies,namely the link distance-resource balanced key provision strategy and the maximum shared link key provision strategy.The proposed strategies are applicable to hybrid DV/CV multi-domain quantum networks,which are typically implemented by GG02-based intra-domain connections and BB84-based inter-domain connections.Furthermore,the multicast-oriented key provision model is formulated,based on which two heuristic algorithms are designed,i.e.,the shared link distance-resource(SLDR)dependent and the maximum shared link distance-resource(MSLDR)dependent multicast-oriented key provision algorithms.Simulation results verify the applicability of the designed algorithms across different multi-domain quantum networks,and demonstrate their superiority over the benchmark algorithms in terms of the success probability of multicast service requests,the number of shared links,and the key resource utilization.展开更多
Beginning with the simple introduction of socket which is the most commonly used application program interfaces in UNIX/LINUX communication domain, the concrete programming procedures to realize multicast and broadcas...Beginning with the simple introduction of socket which is the most commonly used application program interfaces in UNIX/LINUX communication domain, the concrete programming procedures to realize multicast and broadcast based on socket is provided, according to TCP/IP protocol in LINUX system. The acquiring and converting of broadcast destination address and multicast address, the setting of multicast options, the joining in and withdrawing from the multicast group, and the receiving and sending of datagram are all demonstrated in it, the related system calls and simple explication of C programming are also included.展开更多
To meet the bandwidth requirement for the multicasting data flow in ad hoc networks, a distributed on- demand bandwidth-constrained multicast routing （BCMR） protocol for wireless ad hoc networks is proposed. With th...To meet the bandwidth requirement for the multicasting data flow in ad hoc networks, a distributed on- demand bandwidth-constrained multicast routing （BCMR） protocol for wireless ad hoc networks is proposed. With this protocol, the resource reservation table of each node will record the bandwidth requirements of data flows, which access itself, its neighbor nodes and hidden nodes, and every node calculates the remaining available bandwidth by deducting the bandwidth reserved in the resource reservation table from the total available bandwidth of the node. Moreover, the BCMR searches in a distributed manner for the paths with the shortest delay conditioned by the bandwidth constraint. Simulation results demonstrate the good performance of BCMR in terms of packet delivery reliability and the delay. BCMR can meet the requirements of real time communication and can be used in the multicast applications with low mobility in wireless ad hoc networks.展开更多
文摘A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）, large （242-332 m^2） and very large （333-550 m^2） gaps, as well as under closed stands were studied eight years after-the gap creation. Soil samples were taken from three depths, 0-10, 10-20 and 20-30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters： Mg^＋2 concentration of 0-10 cm at medium gap size, bulk density of 10-20 cm at very large gap size as well as K^＋ and Ca^＋2 concentrations at 20-30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent （Sp %） at 0-10cm as well as P and Mg^＋2 at 20--30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca^＋2 at depth 0--10 cm and 10-20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.
基金This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nível Superior-Brasil(CAPES)-Finance Code 001,and by the National Council for Scientific and Technological Development(CNPq).
文摘To verify if the response by Eucalyptus clones in a single-tree plot is influenced by neighboring plants and to determine the effect of missing and/or dominated plants,seven eucalyptus trials in four Brazilian states were analyzed in a randomized complete block design with one plant/plot and 30 replications.Mean annual increment(MAI,m^(3)ha^(-1)per year)was determined for three-year-old clones.The influence of neighboring clones was estimated by a linear regression coefficient between the MAI of each clone/plot and the average of a clonal MAI and its eight neighbors.To determine the effect of missing and/or dominated trees,a correction between the MAI and the area available/plant was applied.Subsequent analysis considered unadjusted and adjusted data for missing and dominated trees.Estimate of accuracy and index of coincidence were used to compare the adjustments.In single-tree plots,clone performances were not influenced by neighboring plants.Experimental accuracy was not increased by any of the adjustments employed and the clone ranking was not altered,and therefore did not justify their use.
基金supported by the National Natural Science Foundation of China(Grant Nos.62201276,62350001,U22B2026,and 62425105)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300701)the Key R&D Program(Industry Foresight and Key Core Technologies)of Jiangsu Province(Grant No.BE2022071)。
文摘As the cornerstone of future information security,quantum key distribution(QKD)is evolving towards large-scale hybrid discrete-variable/continuous-variable(DV/CV)multi-domain quantum networks.Meanwhile,multicast-oriented multi-party key negotiation is attracting increasing attention in quantum networks.However,the efficient key provision for multicast services over hybrid DV/CV multi-domain quantum networks remains challenging,due to the limited probability of service success and the inefficient utilization of key resources.Targeting these challenges,this study proposes two key-resource-aware multicast-oriented key provision strategies,namely the link distance-resource balanced key provision strategy and the maximum shared link key provision strategy.The proposed strategies are applicable to hybrid DV/CV multi-domain quantum networks,which are typically implemented by GG02-based intra-domain connections and BB84-based inter-domain connections.Furthermore,the multicast-oriented key provision model is formulated,based on which two heuristic algorithms are designed,i.e.,the shared link distance-resource(SLDR)dependent and the maximum shared link distance-resource(MSLDR)dependent multicast-oriented key provision algorithms.Simulation results verify the applicability of the designed algorithms across different multi-domain quantum networks,and demonstrate their superiority over the benchmark algorithms in terms of the success probability of multicast service requests,the number of shared links,and the key resource utilization.
文摘Beginning with the simple introduction of socket which is the most commonly used application program interfaces in UNIX/LINUX communication domain, the concrete programming procedures to realize multicast and broadcast based on socket is provided, according to TCP/IP protocol in LINUX system. The acquiring and converting of broadcast destination address and multicast address, the setting of multicast options, the joining in and withdrawing from the multicast group, and the receiving and sending of datagram are all demonstrated in it, the related system calls and simple explication of C programming are also included.
基金The Natural Science Foundation of Zhejiang Province(No.Y1090232)
文摘To meet the bandwidth requirement for the multicasting data flow in ad hoc networks, a distributed on- demand bandwidth-constrained multicast routing （BCMR） protocol for wireless ad hoc networks is proposed. With this protocol, the resource reservation table of each node will record the bandwidth requirements of data flows, which access itself, its neighbor nodes and hidden nodes, and every node calculates the remaining available bandwidth by deducting the bandwidth reserved in the resource reservation table from the total available bandwidth of the node. Moreover, the BCMR searches in a distributed manner for the paths with the shortest delay conditioned by the bandwidth constraint. Simulation results demonstrate the good performance of BCMR in terms of packet delivery reliability and the delay. BCMR can meet the requirements of real time communication and can be used in the multicast applications with low mobility in wireless ad hoc networks.
