用于网络管理系统的智能轮询策略

为提高网络性能管理与故障管理的实时性和效率,研究信息收集轮询策略,提出一种基于马尔可夫链的智能轮询算法。该算法能根据被监视对象参数值的变化,动态调整轮询间隔时间。实验结果表明,与传统等时间轮询算法相比,该算法可以更准确地刻画数据变化特征,降低数据采集失真度并减小网络带宽,其效率和可靠性较高。     

一种高效的网络故障管理算法

随着网络技术的发展，如何有效地进行网络管理的问题日益突出。故障管理是网络管理的核心内容。该文通过对简单网络管理协议SNMP中管理信息传输的轮询控制方式进行了分析，提出了一种新的轮询算法，采用嵌入马尔可夫链和概率母函数的分析方法，给出了轮询算法的数学模型。通过理论计算和仿真实验验证了新的算法提高了网络故障管理的效率。     

基于SNMP的自陷的传递轮询算法

提出了一种基于SNMP网管系统的自陷的传递轮询算法TTP。该算法对传统的自陷的轮询算法进行了改进，引入了传递和分组的思想，在每个分组内部由被管设备的代理来控制轮询数据报的传递，减轻了在轮询过程中管理站的工作，有利于提高大型网络网管系统的工作效率。     

一种基于双令牌的蓝牙调度算法

调度算法是短距离无线通信技术的主要问题。蓝牙网络中使用的Round Robin (RR)轮询调度算法严重影响了系统的性能，本文针对这个问题提出了一种改进的蓝牙调度算法——双令牌随机(DTPR)轮询算法．此算法有两个重要特点：一是访问采用随机次序解决从设备之间的不公平性；二是采用优先级调度策略，对拥有令牌的主从设备对进行调度，缩短了轮询周期。并对本文提出的算法与现已提出的算法进行了仿真实验，结果表明，本文提出的算法在系统的吞吐量、传输时延和公平性方面都优于现有的其它算法。     

基于广播SNMP的网络管理并行轮询算法*

面对网络融合环境下网络规模大、分布广、设备多的实际需求,传统网络管理系统通过依次轮询设备进行数据采集存在轮询周期长、实时性低、轮询数据量多等缺点,提出了一种基于广播SNMP的数据采集并行轮询算法。该算法在轮询时,通过向每个网段发送广播SNMP数据包的方式并行轮询被管设备,减少轮询数据包的数量,减轻管理站的负担,缩短轮询周期;在接收设备回复数据包时,针对接收和处理速度不匹配的情况,采用多线程自适应并行处理环形缓存的方法,达到高速数据接收的目的。系统测试结果表明,通过广播方式的轮询可以有效缩短轮询周期,减少轮     

基于Android平台的智能家居系统设计

为了实现家居生活智能、方便等目的,提出一种基于Android平台的智能家居系统。采用内外网通信方式,使得当家庭宽带不可用时仍能通过内网实现对家居设备的控制。将用户配置信息、设备信息存在网关使得不同客户端能信息共享,实现动态添加、删除动作。采用推送而不是轮询,实时性好。客户端APP功能齐全,云计算的使用实现了外网控制,同时便于未来的系统扩展。     

融合颜色与光照信息的改进AKAZE图像匹配算法

传统AKAZE算法主要以图像的灰度信息作为输入,忽略了颜色与光照信息,且存在过多的冗余特征点。提出一种融合颜色与光照信息的改进图像匹配算法。在图像原始灰度信息中增加颜色补偿量和光照补偿量,克服传统AKAZE算法未利用颜色和光照信息来区分同名点的缺点。在特征点邻域内计算欧式距离和区域重复率以确定重叠程度较高的相邻特征点,比较相邻特征点的响应强度,将响应强度值较小的特征点作为冗余点并删除。在图像匹配后利用随机一致性算法剔除误匹配点对,通过并行运算对算法进行加速。实验结果表明,该算法可以有效识别同名点并剔除图像中的冗余点,运行效率优于SIFT和SURF等算法。     

网络安全设备故障管理中智能轮询策略的研究

为保证系统在给定故障管理带宽阈值下，仍然具有较高的故障征兆信息采集频率，该文提出了一种故障管理智能轮询算法。该算法根据故障征兆参数值的时间属性，使用离散傅立叶变换将参数值分解为不同频率的正弦函数，进而根据系统预先设定的各参数故障告警阈值，决定使用分解得到的最大或最小频率作为轮询间隔时间。最后，通过试验证明该算法具有较高的效率和可靠性。     

基于Web-Socket协议的推送数据技术在监控系统中的应用研究

软件即服务SaaS已成为一种新的软件构架。在SaaS构架下,浏览器成为应用的入口,浏览器与服务器之间采用全双工通信的需求日趋增多。在分析基于HTTP协议的AJAX轮询技术的基础上,针对AJAX轮询和AJAX长轮询技术在获取服务器更新数据方面会增加服务器计算资源负载的不足,提出和描述了采用Web-Socket协议建立全双工通信的实现方法,设计了在B/S构架模式中通信两端可主动推送数据信息的一种软件构架技术解决方案。该软件构架方案已在数据交换监控系统中得到实际应用,其中"服务器推送信息核心算法"和"任务状态管理器算法"的设计被予以详细描述。     

顺序分布式变长分组调度算法:SDMCRR

通过引入分布式思想对CRR调度算法进行改进，提出了一种基于输入排队VOQ结构的输入端口轮转和输出端口轮询的顺序分布式改进补偿轮询调度算法SDMCRR。并通过分析以及和其它轮询算法的比较，得出该算法具有单个报文调度O（1）的复杂度、较好的隔离恶意流的公平性和时延特性。     

Seamless handover supported by parallel polling and dynamic multicast group in connected WLAN micro-cells system

WLAN (Wireless Local Area Network) has been seen to be one of the promising access technologies that adapts to 4G cellular network systems in providing very high speed connection with QoS guarantee through the polling function. However, when the handover happens, the contention-based medium access mechanism which is mainly used in WLAN is invoked and introduces unbounded transmission delay due to idle time periods and retransmission because of collision during the handover. If this technique is expanded to use in a microcellular network such as connected WLAN micro-cells, contention-based mechanism, therefore, should not be used to handle the MT’s handover, especially for vehicular users who change access point every few seconds. To overcome these difficulties in handover, we introduce parallel polling scheme in dynamic LMC (Logical Macro Cell) which can reduce delays much and remove packet loss rate. LMC is a virtual single macro cell which is built on a multicast group of adjacent micro-cells. In the same LMC, polling signals are sent from every BS (base station) to give MT (mobile terminal) permission to access one of these BSs. Instead of wasting much time to contend for resources of a new BS during handover, the MT answers the polling as an acknowledgment to connect to that new BS. The polling response is controlled to multicast to all BSs of the same LMC via the core network to synchronize for the next polling cycle. LMC is controlled to dynamically change when the MT comes in a new BS to make polling signals be continuous in a new LMC. Through analytical and simulation results, we show that the parallel polling scheme can achieve no handover latency, no packet loss and maintain mobile users’ throughput stably in the high traffic load condition though it causes overhead on the neighboring cells in both of wired and wireless sections. At speeds of up to70 m/s, the MT can still maintain its stable connection. OMNeT++ simulator with INET project is used to evaluate our proposal.     

Real-time network monitoring scheme based on SNMP for dynamic information

An efficient and automated network management is required in large and complex networks since it is very difficult to manage them only with human effort. In response to this need, the Simple Network Management Protocol (SNMP) has been developed and adopted as the de facto standard. Some management information changes with time and the management station needs to monitor its value in real time. In such a case, polling is generally used in the SNMP because the management station can query agents periodically. However, the polling scheme needs both request and response messages for management information every time, which results in network traffic increase. In this paper, we suggest a real-time network monitoring method for dynamic information to reduce the network traffic in SNMP-based network management. In the proposed strategy, each agent first decides its own monitoring period. Then, the manager collects them and approves each agent's period without modification or adjusts it based on the total traffic generated by monitoring messages. After receiving a response message containing the monitoring period from the management station, each agent sends management information periodically without the request of management station. To evaluate the performance of the proposed real-time monitoring method, we implemented it and compared the network traffic and monitoring quality of the proposed scheme with the general polling method.     

基于NS-2的自适应差额IEEE 802.11 PCF轮询机制

在研究无线局域网IEEE 802.11标准点协调功能PCF(Point Coordination Function)机制不足的情况下,针对其中Round Robin轮询机制存在的QoS(Quality of Service)不能得到有效保障的问题,提出了一套自适应差额轮询调度算法解决方案,阐述了算法的核心思想,介绍了调度机制的执行过程,并且通过修改PCF源代码,在网络模拟器NS-2平台上对算法进行了脚本模拟.实验结果表明,自适应差额IEEE 802.11 PCF轮询算法比传统的Round Robin算法在端到端延迟、系统吞吐量和包延迟等QoS服务性能方面都有显著的提高.     

WSN-UAV基于FPGA的异步带优先级数据转发轮询控制系统

在林、农作物监测作业中,可通过散布无线传感器节点形成的自组织WSN收集作物环境信息。将UAV应用于分簇式WSN作为移动的数据收集节点sink时,UAV不仅需要转发各簇首节点的信息,还需转发自带传感器检测到的重要信息。为了保证UAV传感器检测信息及时转发,并进一步降低簇首节点能耗,延长WSN网络寿命,提出异步带优先级的数据转发轮询控制系统方案,应用马尔可夫链和概率母函数进行建模以分析系统性能。用自带异步读写FIFO功能的FPGA作为主控器件,基于FPGA设计该轮询系统硬件电路结构,验证了该轮询控制系统的可行性和高效性。实验结果表明,该方案能保证UAV及时转发重要数据,缩短服务延迟,提高WSN能耗效率,优化系统性能。     

无线Mesh网络中基于奖励机制的均衡传输方案

针对无线Mesh网络存在自私节点而造成的双向流量的均衡问题,提出了一种基于奖励机制的均衡传输方案。首先,推导出了每个传输访问点(TAP)的双向目标吞吐量。然后,提出一种奖励机制,通过信用币和代币支付策略来鼓励闲置TAP转发数据,同时使网关尽可能均衡地向TAP传输下行数据。在一个具有3个TAP的无线Mesh网络上仿真结果表明,该方法能够在存在自私节点情况下确保双向流量的均衡。     

Efficiency-driven selection of bandwidth request mechanism in broadband wireless access networks

To avoid collisions in WiMAX networks, the connections in Subscriber Stations (SSs) use a request–grant process to acquire transmission resources from the Base Station (BS). In accordance with the IEEE 802.16 standard, the request–grant process is accomplished using either a unicast polling method or a contention request method. In WiMAX systems, the number of bandwidth-request (BR) slots per frame is limited. Thus, to enhance the network performance, the BR slots must be used in the most efficient manner possible. In practical WiMAX systems, the offered network load varies over time, and thus the strict use of either the unicast polling method or the contention request method results in a poor utilization efficiency of the BR slots. Accordingly, the present study proposes a scheme designated as Efficiency-Driven Selection of Bandwidth Request (EDSBR), in which the request–grant mechanism is adjusted dynamically on a frame-by-frame basis in accordance with the network conditions. The performance of the proposed scheme is evaluated by simulations. The results show that EDSBR achieves a more efficient utilization of the BR slots than the unicast polling scheme or the contention request scheme, and therefore yields an improved network performance.