RMAC: A Reliable MAC Protocol Supporting Multicast for Wireless Ad Hoc Networks

This paper presents a new reliable MAC protocol called “RMAC”supporting reliable multicast for wireless ad hoc networks. By utilizing the busy tones to realize the multicast reliability, RMAC has three novelties： （1） it uses a variablelength control frame to stipulate an order for the receivers to respond, thus solving the feedback collision problem; （2） it extends the usage of busy tone for preventing data frame collisions into the multicast scenario; and （3） it introduces a new usage of busy tone for acknowledging data frames positively. In addition, RMAC is generalized into a comprehensive MAC protocol that provides both reliable and unreliable services for all the three modes of communications： unicast, multicast, and broadcast, making it capable of supporting various upper-layer protocols. The evaluation shows that RMAC achieves high reliability with very limited overhead. RMAC is also compared with other reliable MAC protocols, showing that RMAC not only provides higher reliability but also involves lower cost.     

Internet连续媒体多播技术综述

Continuous media multicast has been an important component of many networked services such as audio-visual broadcast and video conferencing.The problems of scalability,congestion control,heterogeneity and reliability,which confront Internet continuous media multicast,are presented first,and then overview of the adaptive rate control schemes and techniques to solve these problems are stated.Finally,we discuss some treds and unsolved issues in the field.     

一种面向任务关键系统的RISC风格的协作构架

The collaborative framework for the mission and safety critical system is required to support multiple quality of service properties. A RISC style collaborative framework is provided to meet this requirement. The collaborative characters of mission and safety critical system are discussed and the reliable multicast that supports collaborative computing is discussed emphsis on.     

一类不确定Lur'e奇异系统的可靠鲁棒H_∞跟踪控制(英文)

The problem of reliable robust H_∞tracking control for a class of uncertain Lur'e singular systems is studied.A practical and general failure model of actuator and sensor is considered by using convex polytopic uncertainties to describe control surface impairment.Some sufficient conditions are presented for the case of actuator,sensor and control surface failures in terms of linear matrix inequalities (LMIs).The resultant control systems are reliable in that they guarantee closed-loop system robust stability with H_∞performance and the output tracking the reference signal without steady-state error when all control components are operational as well as when some control components experience failures.Finally,a numerical example is given to show the effectiveness of the proposed methods.     

A survey on cross-discipline of control and game

In recent years, the cross discipline of game theory and the control theory has been emerging. This paperwill survey this newly growing direction. First, the development from optimization of control systems to games consisting of multi-purpose controls is introduced, which demonstrates the close relationship between control theory and game theory. Secondly, the control-oriented game is considered. Three kinds of problems are discussed in details: i) Learning strategy in game theory, which is basically the same as the adaptive control; ii) state space approach for control systems is applied to evolutionary games; and iii)machine-human game is treated as the optimal control problem. Finally, after introducing some new results on potential games, the game-based control is studied. Three kind of control problems using potential games are investigated: i) The consensus of multi-agent systems is considered; ii) the maximization of the distributed coverage of multi-agents on a graph is discussed; and iii) the congestion control is investigated using congestion game technology. Some other game-based control problems are also briefly introduced. A prediction for the control systems in next generation is presented in conclusion.     

Quantum learning control using differential evolution with equally-mixed strategies

Learning control has been recognized as a powerful approach in quantum information technology. In this paper, we extend the application of differential evolution (DE) to design optimal control for various quantum systems. Various DE methods are introduced and analyzed, and EMSDE featuring in equally mixed strategies is employed for quantum control. Two classes of quantum control problems, including control of four-level open quantum ensembles and quantum superconducting systems, are investigated to demonstrate the performance of EMSDE for learning control of quantum systems. Numerical results verify the effectiveness of the EMSDE method for various quantum systems and show the potential for complex quantum control problems.     

Constrained optimal steady-state control for isolated traffic intersections

The steady-state or cyclic control problem for a simplified isolated traffic intersection is considered. The optimization problem for the green-red switching sequence is formulated with the help of a discrete-event max-plus model. Two steady-state control problems are formulated： optimal steady-state with green duration constraints, and optimal steady-state control with lost time. In the case when the criterion is a strictly increasing, linear function of the queue lengths, the steady-state control problems can be solved analytically. The structure of constrained optimal steady-state traffic control is revealed, and the effect of the lost time on the optimal solution is illustrated.     

基于ECN的单播流与多播流间带宽共享算法

An ECN-based implementing bandwidth-sharing algorithm for unicast and multicast flows is presented.The algorithm uses a bandwidth allocation strategy to give an incentive to multicast flows in bandwidth allocation according to algorithm of the number of receivers, and to assure the unicast flows get their bandwidth shares fairly.Provided best-effort networks, an ECN-based congestion control algorithm is used to implement differentiated service in bandwidth allocation between unicast flows and multicast flows. In implementation, we solve the problems such asreceiver‘s number estimation, the RTT estimation and compromise between convergence and stability.The simulation results show that the algorithm can implement bandwidth sharing for TCP flows and multicast flows. Atthe same time, the algorithm not only allocates more bandwidth to multicast flows, but promises TCP flows to get their fair bandwidth share.     

Algorithm of simulation time synchronization over large-scale nodes

In distributed simulation, there is no uniform physical clock. And delay cannot be estimated because of jitter. So simulation time synchronization is essential for the event consistency among nodes. This paper investigates time synchronization algorithms over large-scale distributed nodes, analyzes LBTS （lower bound time stamp） computation model described in IEEE HLA standard, and then presents a grouped LBTS model. In fact, there is a default premise for existing algorithms that controi packets must be delivered via reliable transportation. Although, a theorem of time synchronization message＇s reliability is proposed, which proves that only those control messages that constrain time advance need reliability. It breaks out the default premise for reliability. Then multicast is introduced into the transmis- sion of control messages, and algorithm MCTS （multi-node coordination time synchronization） is proposed based on multicast. MCTS not only promotes the time advance efficiency, but also reduces the occupied network bandwidth. Experiment results demonstrate that the algorithm is better than others in both time advance speed and occupied network bandwidth. Its time advance speed is about 50 times per second when there are 1000 nodes, approximately equal to that of similar systems when there are 100 nodes.     

Multicast address management and connection control based on hierarchical autonomous structure

Multicast capability,including multicast address and multicast routing mechanisms,at the network layer is necessary in order to reduce the bandwidth requirements of multiparty,multicast applications.Based on hierarchical autonomous structure in accordance with the self-organization topologies of Internet,the paper puts forward a multicast address management scheme that is shown to be robust and scalable.Connection control hierarchy(CCH) based on master/slave relationship and a simple efficient building algorithm of multi-point connection is also built.The paper also describes the normal operations of multicast address management and multi-point connection controller.Through simulation experiment,HAM CM and DDM of Multicast Address Allocation are compared.HAM integrates the merits of CM and DDM,which is efficient as a whole,robust and scalable.CCH raises the efficiency of connection control,and is highly robust,flexible and scalable.