MapReduce is a popular program- ming model for processing large-scale datasets in a distributed environment and is a funda- mental component of current cloud comput- ing and big data applications. In this paper, a hea...MapReduce is a popular program- ming model for processing large-scale datasets in a distributed environment and is a funda- mental component of current cloud comput- ing and big data applications. In this paper, a heartbeat mechanism for MapReduce Task Scheduler using Dynamic Calibration （HMTS- DC） is proposed to address the unbalanced node computation capacity problem in a het- erogeneous MapReduce environment. HMTS- DC uses two mechanisms to dynamically adapt and balance tasks assigned to each com- pute node： 1） using heartbeat to dynamically estimate the capacity of the compute nodes, and 2） using data locality of replicated data blocks to reduce data transfer between nodes. With the first mechanism, based on the heart- beats received during the early state of the job, the task scheduler can dynamically estimate the computational capacity of each node. Us- ing the second mechanism, unprocessed Tasks local to each compute node are reassigned and reserved to allow nodes with greater capacities to reserve more local tasks than their weaker counterparts. Experimental results show that HMTS-DC performs better than Hadoop and Dynamic Data Placement Strategy （DDP） in a dynamic environment. Furthermore, an en- hanced HMTS-DC （EHMTS-DC） is proposed bv incorporatin historical data. In contrastto the ＂slow start＂ property of HMTS-DC, EHMTS-DC relies on the historical computation capacity of the slave machines. The experimental results show that EHMTS-DC outperforms HMTS-DC in a dynamic environment.展开更多
An ad hoc network is a group of wireless mobile computers(or nodes),in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range.Beca...An ad hoc network is a group of wireless mobile computers(or nodes),in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range.Because of node mobility and power limitations,the network topology changes frequently.Routing protocol plays an important role in the ad hoc network.A recent trend in ad hoc network routing is the reactive on-demand philosophy where routes are established only when required.As an optimization for the current Dynamic Source Routing Protocol,a secure and pragmatic routes selection scheme based on Reputation Systems was proposed.We design the Secure and Pragmatic Routing protocol and implement simulation models using GloMoSim.Simulation results show that the Secure and Pragmatic Routing protocol provides better experimental results on packet delivery ratio,power consumption and system throughput than Dynamic Source Routing Protocol.展开更多
To accurately track computer viruses,an overlay network that monitors the activities of viruses is constructed.Identifying and locating nodes infected by virus on network is achieved by a naming system in which a node...To accurately track computer viruses,an overlay network that monitors the activities of viruses is constructed.Identifying and locating nodes infected by virus on network is achieved by a naming system in which a node in the network is mapped to a unique serial number of the hard-drive.By carefully monitoring and recording sensitive communication between local system and remote nodes on the network,and suspicious operations on files that originate from remote nodes and entered via some form of file transfer,activities of viruses in both local and network level are recorded and ready for future analysis.These data can also be used in analysis of the mechanism of a computer virus as well as its spreading mode and pattern.展开更多
文摘MapReduce is a popular program- ming model for processing large-scale datasets in a distributed environment and is a funda- mental component of current cloud comput- ing and big data applications. In this paper, a heartbeat mechanism for MapReduce Task Scheduler using Dynamic Calibration （HMTS- DC） is proposed to address the unbalanced node computation capacity problem in a het- erogeneous MapReduce environment. HMTS- DC uses two mechanisms to dynamically adapt and balance tasks assigned to each com- pute node： 1） using heartbeat to dynamically estimate the capacity of the compute nodes, and 2） using data locality of replicated data blocks to reduce data transfer between nodes. With the first mechanism, based on the heart- beats received during the early state of the job, the task scheduler can dynamically estimate the computational capacity of each node. Us- ing the second mechanism, unprocessed Tasks local to each compute node are reassigned and reserved to allow nodes with greater capacities to reserve more local tasks than their weaker counterparts. Experimental results show that HMTS-DC performs better than Hadoop and Dynamic Data Placement Strategy （DDP） in a dynamic environment. Furthermore, an en- hanced HMTS-DC （EHMTS-DC） is proposed bv incorporatin historical data. In contrastto the ＂slow start＂ property of HMTS-DC, EHMTS-DC relies on the historical computation capacity of the slave machines. The experimental results show that EHMTS-DC outperforms HMTS-DC in a dynamic environment.
基金The National Natural Science Foundation of China (No.60403027)
文摘An ad hoc network is a group of wireless mobile computers(or nodes),in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range.Because of node mobility and power limitations,the network topology changes frequently.Routing protocol plays an important role in the ad hoc network.A recent trend in ad hoc network routing is the reactive on-demand philosophy where routes are established only when required.As an optimization for the current Dynamic Source Routing Protocol,a secure and pragmatic routes selection scheme based on Reputation Systems was proposed.We design the Secure and Pragmatic Routing protocol and implement simulation models using GloMoSim.Simulation results show that the Secure and Pragmatic Routing protocol provides better experimental results on packet delivery ratio,power consumption and system throughput than Dynamic Source Routing Protocol.
基金Project is supported by the National Nature Science Foundation of China(Grant No.60672142,60772053,90304005)New architecture and technology for the Internet information sharing,The relation and Countermeasure of Application Layer Behavior and Collective Performance of Internet,Forecast of Traffic Model on Internet+1 种基金Supported by National Basic Research Program of China,(Grant No.2007CB307100,Project No.2007CB307105)The Theory of Mobility and Sensor Network under The Integrated Network and the Universal Ap-plicable Service System
文摘To accurately track computer viruses,an overlay network that monitors the activities of viruses is constructed.Identifying and locating nodes infected by virus on network is achieved by a naming system in which a node in the network is mapped to a unique serial number of the hard-drive.By carefully monitoring and recording sensitive communication between local system and remote nodes on the network,and suspicious operations on files that originate from remote nodes and entered via some form of file transfer,activities of viruses in both local and network level are recorded and ready for future analysis.These data can also be used in analysis of the mechanism of a computer virus as well as its spreading mode and pattern.
