AODV协议在渔船超短波自组网中的仿真与分析

为了验证AODV协议在渔船超短波自组网中的可行性并研究它的工作性能,使用OPNET仿真软件,选择数据包投递率、平均时延、归一化路由开销和平均跳数这4个衡量指标对AODV路由协议进行性能评估,并通过改变网络规模和节点移动速度来分析这些参数对AODV协议工作性能的影响。仿真结果表明,AODV协议适用于渔船速度为10m/s以内且业务量较低的小型渔船超短波网络。为了提高AODV协议在此网络中的工作性能,最后还提出了改进建议。     

无线传感器网络中高效移动汇点规划算法

在带有移动汇点(MS)的无线传感器网络(WSN)数据收集应用中,采用基于代理的数据收集模式可以有效缩短MS慢速引起的数据收集延迟问题.以提高WSN数据收集的能量效率和缩短数据收集延时为目标,给出了一种MS轨道规划算法MS-TPA. MS-TPA主要包括RN竞选和MS移动规划两个阶段.剩余能量优先的RN竞选机制能够平衡网络节点的能量消耗,MS移动规划算法能够缩短数据收集的延迟问题.仿真实验验证了所提出算法的有效性.     

战场环境中基于簇的WSN生存性路由协议

当无线传感网络应用于战场环境时,复杂恶劣的网络环境以及传感节点受限的能源、内存和通信能力导致节点容易失效、遭受攻击或被俘获,从而影响侦察任务的完成。本文提出一种基于簇的生存性路由协议—SRPC,该协议通过密钥协商和身份认证等机制抵御恶意节点的攻击;并在主簇头被摧毁后启用备用簇头链将监测数据传输到基站。仿真结果表明,SRPC协议可以在均衡能耗的基础上有效抵御恶意节点的攻击,并在簇头节点遭受攻击或者被摧毁后保证数据包的可靠投递,提高了WSN在战场侦察环境中的生存能力。     

水声传感器网络中一种基于多种群萤火虫的路由协议

针对水声传感器网络的特殊性,提出一种基于多种群萤火虫的路由协议,以确保数据包在水声传感器网络各节点之间正确、高效地转发。首先构造水声传感器网络的网络模型;然后,设计3种类型的萤火虫,通过各种萤火虫之间的协同工作提高路由路径构建的自适应性并实现路由路径的选择和优化。仿真实验结果表明,与传统的水声传感器网络路由协议相比,在节点数量相同情的况下,该路由协议的数据包传送率更高,平均端到端延时更低,并且在平均数据传送率相同情况下,网络吞吐量更大。     

一种电力线载波路由远程升级方法

提出一种电力线载波路由软管理平台远程升级方法,以实现路由管理平台的安全可靠、低廉成本的远程管理.该方法设计了一套完整的通信协议和升级流程,并提出了避免盲目升级、断点续传、可靠加载维护等机制,已经在实验室和现场通过测试,实现了载波路由平台的远程实时更新,大大降低了维护成本.该方法具有一定的通用性,可以应用于电力线载波通信自动抄表领域由主站、集中器、GPRS模块、载波路由管理平台组成的系统中,可提高载波路由系统的可维护性和可扩展性.     

An ideal multi-secret sharing scheme based on MSP

A multi-secret sharing scheme is a protocol to share m arbitrarily related secrets s₁, … , s_m among a set of n participants. In this paper, we propose an ideal linear multi-secret sharing scheme, based on monotone span programs, where each subset of the set of participants may have the associated secret. Our scheme can be used to meet the security requirement in practical applications, such as secure group communication and privacy preserving data mining etc. We also prove that our proposed scheme satisfies the definition of a perfect multi-secret sharing scheme.     

Modeling discrete event scalable network systems

Scalability in simulation tools is one of the most important traits to measure performance of software. The reason is that today’s Internet is the main instance of a large-scale and highly complex system. Simulation of Internet-scale network systems has to be supported by any simulation tool. Despite this fact, many network simulators lacks support for building large models. In this work, in order to propose a new approach for scalability issue in network simulation tools, a network simulator is developed based on behavior of honeybees and high performance DEVS, modular and hierarchical system theoretic approach. A biologically-inspired discrete event modeling approach is described for studying networks’ scalability and performance traits. Since natural systems can offer important concepts for modeling network systems, key adaptive and emergent attributes of honeybees and their societal properties are incorporated into a set of simulation models that are developed using the discrete event system specification approach. Large-scale network models are simulated and evaluated to show the benefits of nature-inspired network models.     

A Newton-like finite element scheme for compressible gas flows

Semi-implicit and Newton-like finite element methods are developed for the stationary compressible Euler equations. The Galerkin discretization of the inviscid fluxes is potentially oscillatory and unstable. To suppress numerical oscillations, the spatial discretization is performed by a high-resolution finite element scheme based on algebraic flux correction. A multidimensional limiter of TVD type is employed. An important goal is the efficient computation of stationary solutions in a wide range of Mach numbers, which is a challenging task due to oscillatory correction factors associated with TVD-type flux limiters. A semi-implicit scheme is derived by a time-lagged linearization of the nonlinear residual, and a Newton-like method is obtained in the limit of infinite CFL numbers. Special emphasis is laid on the numerical treatment of weakly imposed characteristic boundary conditions. Numerical evidence for unconditional stability is presented. It is shown that the proposed approach offers higher accuracy and better convergence behavior than algorithms in which the boundary conditions are implemented in a strong sense.     

Complexity and design of QoS routing algorithms in wireless mesh networks

Quality of service (QoS) provisioning in wireless mesh networks (WMNs) is an open issue to support emerging multimedia services. In this paper, we study the problem of QoS provisioning in terms of end-to-end bandwidth allocation in WMNs. It is challenging due to interferences in the networks. We consider widely used interference models and show that except a few special cases, the problem of finding a feasible path is NP-complete under the models. We propose a k-shortest path based algorithmic framework to solve this problem. We also consider the problem of optimizing network performance by on-line dynamic routing, and adapt commonly used conventional QoS routing metrics to be used in WMNs. We find the optimal solutions for these problems through formulating them as optimization models. A model is developed to check the existence of a feasible path and another to find the optimal path for a demand; moreover, an on-line optimal QoS routing algorithm is developed. Comparing the algorithms implemented by the proposed framework with the optimization models shows that our solution can find existing feasible paths with high probability, efficiently optimizes path lengths, and has a comparable performance to the optimal QoS routing algorithm. Furthermore, our results show that contrary to wireline networks, minimizing resource consumption should be preferred over load distribution even in lightly loaded WMNs.