Publish/Subscribe middleware is getting more and more attentions for its feature of loose *** some scenarios,Subscribersof a topic need not all the information belonging to that topic, but only those of interest. To f...
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Publish/Subscribe middleware is getting more and more attentions for its feature of loose *** some scenarios,Subscribersof a topic need not all the information belonging to that topic, but only those of interest. To fulfill this requirement,some kind of information selection mechanism is needed. In this paper, a filter-based information selection mechanism is proposed, which is compliant with OMG DDS specification. Then it is implemented in a publish/subscribe middleware prototype *** the mechanism, a publish/subscribe middleware can use the compiler generated by Flex&Bison to compile the filtering rules of the users,which are conform to SQL-like syntax,and generate the filtering syntax *** the subscriber side, when receiving a sample, the middleware substitute the values of the sample into the corresponding positions in the filtering syntax tree. By traversing the tree, the middleware makes the filtering decision. Experiment results reveal that the proposed mechanism is effective.
The existence of selfish nodes seriously affects the routing performance of opportunistic networks (OppNet). To protect the OppNet against the nodes' selfish behavior, a credit-based selfish nodes detection mechan...
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The existence of selfish nodes seriously affects the routing performance of opportunistic networks (OppNet). To protect the OppNet against the nodes' selfish behavior, a credit-based selfish nodes detection mechanism was proposed to make it possible to keep away from such nodes during the process of message forwarding. The mechanism leverages 2-ACK messages to observe the nodes' behavior. Then the credit value was calculated based on the observation information and accordingly acts as the metric to distinguish the selfish nodes. Simulation results show that, when coupled with various routing algorithms, the mechanism could detect selfish nodes out accurately, and improve network performance effectively in terms of delivery rate and traffic load.
In event-driven wireless sensor networks, many redundant packets flow from monitored sites through the network and to the sink, resulting in a typical funnel effect which affects event reliability, negatively. Taking ...
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In event-driven wireless sensor networks, many redundant packets flow from monitored sites through the network and to the sink, resulting in a typical funnel effect which affects event reliability, negatively. Taking this transport property into account, a differentiated priority queue management scheme is presented, in which the packets with same event identification are prioritized according to their arrival sequence, and scheduled differentially. The queue model, packet prioritization strategy and event table maintaining methods are examined in detail. Simulation results show that the queue management scheme can improve event reliability of event-driven sensor networks in terms of event detection ratio, accuracy ratio, and event delay efficiently.
The research was on the influence of transmission distance respectively on energy consumption and transmission rate in wireless sensor network. The views of traditional work on this impact was not so precise, which wa...
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The research was on the influence of transmission distance respectively on energy consumption and transmission rate in wireless sensor network. The views of traditional work on this impact was not so precise, which was essential to the performance of WSN. The sensor node used, experimental environment and design have been introduced;Then the packet loss ratio for different transmission distance have been examined experimentally, and their functional relation by fitting the experimental data have been acquired;finally, considering packet retransmission based on that conclusion at the same time, focused on the variance of energy cost and transmission rate with distance. The main contribution is to acquire the quantitative effect evaluation of one-hop transmission distance and performance in WSN.
The flow and congestion control methods based on one-shot game model with non-cooperative game theory can explain the non-cooperative behavior of Internet ***,the low effciency of equilibrium solutions affects their *...
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The flow and congestion control methods based on one-shot game model with non-cooperative game theory can explain the non-cooperative behavior of Internet ***,the low effciency of equilibrium solutions affects their *** the behavior of flow and congestion control based on infinitely repeated game models is addressed;the repeated and infinitely repeated flow and congestion control game model is presented; the existence and optimization of the Nash equilibrium point are proved;the discount factor in repeated game is discussed;the punishment and threat strategy to users'misbehavior is studied in N-users infinitely flow control game;the punishment restrictive method of users'behavior is designed in infinitely and finitely games;finally,a flow control algorithm based on repeated game,FCAR,is provided based on the conclusions of repeated game *** results of experiment and simulation show that FCAR algorithm could regularize and restrict users' misbehavior *** algorithm can also make non-cooperative Internet users achieve cooperation in order to optimize the utility of the whole flow and congestion control system.
Considering that intravenous in blood infusion, usually applied without a proper control of the progress and velocity under unreliable manual monitoring practice, is the most popular and frequent clinical activity thr...
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Service composition was the core problem of service computing, the validity and reliability of service composition had become the premise of service execution. A method was presented which utilizes the finite state ma...
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Service composition was the core problem of service computing, the validity and reliability of service composition had become the premise of service execution. A method was presented which utilizes the finite state machine (FSM) to model the business process's state transitions, and described the required properties with Alloy language. Then, Alloy model was used to formalize the service FSM and the required properties of the system. Finally, Alloy Analyzer was used to verify the model that whether the required properties were satisfied. It is shown that the method of Alloy-based verification of the service composition is of good feasibility.
Vehicular Ad hoc networks (VANET) consists of several vehicular nodes and uses 802.11p protocol for communication. Because of its unique characteristics, such as fast speed, serious Doppler effect, large node number e...
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While the traditional Web, Email and other Internet applications are still used large-scale, Internet applications, such as typical P2P resource sharing, streaming, games, instant messaging and other new applications ...
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Broadcast is a hot topic in wireless sensor network research. The main challenges are from network instability and complexity of communication collision. Currently, the broadcast protocols for sensor network focus on ...
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