Finding Best Matching Community for Common Nodes in Mobile Social Networks

The increase of mobile data users has created traffic congestion in current cellular networks. Due to this, mobile network providers have been facing difficulty in delivering the best services for customers. Since, detecting community in mobile social network is a valuable technique to leverage the downlink traffic congestion by enhancing local communications within the community, it attracts the attention of many researchers. Therefore, developing an algorithm, which detects community, plays a key role in mobile social network. In this paper, first, we proposed external density metrics to detect mobile social network. External density is defined as the ratio of outgoing links to total links of the community. Second, method to find the best group for common node is proposed. Therefore, an external density algorithm, makes a fair partition by grouping common nodes to a community with relatively higher external density. As a result, the overall modularity value of the network has increased. Third, the proposed algorithm is evaluated. Hence, the evaluation results confirm that our proposed approach has demonstrated good performance improvements than traditional methods.

     

MANET中基于邻居节点的重传控制算法

针对移动Ad Hoc网络传统重传机制存在的局限性,提出了一种新的重传控制算法(EX-TCGM),利用传输路径上的邻居节点传输丢失的数据包,使得路由上的任何节点都能够重传,并从理论上对该算法的有效性进行了分析.通过计算机仿真,并与按需距离矢量路由协议(AODV)、机会路由协议(ExOR)和分组移动传输控制方法(TCGM)进行了性能对比和分析,证明了EX-TCMG的有效性.     

Mobile Target Positioning Using Refining Distance Measurements with Inaccurate Anchor Nodes in Chain-Type Wireless Sensor Networks

As a class of long and narrow structures widely exist such as the river, road, mine tunnel, pipe, chain-type wireless sensor networks (CWSN) can be applied to monitor these environments. The accurate position estimation is a key technology for the mobile target in CWSN. This paper proposes an innovative positioning method to estimate the position of mobile target. Firstly, wireless signals can be affected by measurement noises, coordinate errors of anchor nodes, and chain scene structure. Kernel canonical correlation analysis is applied to analyze the correlation coefficients of these nonlinear wireless signal sets. Secondly, we search out two maximum correlative sets of wireless signals and integrate them into a set of optimal wireless signals. Thirdly, the uncertainty coordinate of anchor node is modeled and the position of mobile target is estimated under measurement and geometry constraints. Furthermore, we simulate the proposed method for mobile target, in comparison with the weighted least squares (WLS) and CHAN methods. Estimation results indicate that the proposed method can refine distance measurement accuracy and perform better positioning performance than WLS and CHAN methods, when we vary the conditions of TDOA/AOA measurement errors, anchor nodes coordinate errors, and anchor nodes spacing distance. Finally, the actual positioning experiments are implemented in a corridor, which show that the practical estimation results are similar to the simulation results.     

Incorporating Data from Multiple Sensors for Localizing Nodes in Mobile Ad Hoc Networks

The ad hoc network localization problem deals with estimating the geographical location of all nodes in an ad hoc network, focusing on those nodes that do not have a direct way (for example, GPS) to determine their own location. Proposed solutions to the ad hoc localization problem (AHLP) assume that nodes are capable of measuring received signal strength indication (RSSI) and/or are able to do coarse (sectoring) or fine signal angle-of-arrival (AoA) measurements. Existing algorithms exploit different aspects of such sensory data to provide either better localization accuracy or higher localization coverage. However, there is a need for a framework that could benefit from the interactions of nodes with mixed types of sensors. In this paper, we study the behavior of RSSI and AoA sensory data in the context of AHLP by using both geometric analysis and computer simulations. We show which type of sensor is better suited for which type of network scenario. We study how nodes using either, both, or none of these sensors could coexist in the same localization framework. We then provide a general particle-filtering framework, the first of its kind, that allows heterogeneity in the types of sensory data to solve the localization problem. We show that, when compared to localization scenarios where only one type of sensor is used, our framework provides significantly better localization results. Furthermore, our framework provides not only a location estimate for each nonanchor, but also an implicit confidence measure as to how accurate this estimate is. This confidence measure enables nodes to further improve on their location estimates using a local, iterative one-hop simple message exchange without having to rely on synchronized multiphase operations like in traditional multilateration methods.     

GUIDE-gradient: A Guiding Algorithm for Mobile Nodes in WLAN and Ad-hoc Networks

Whereas there is a lot of work related to finding the location of users in WLAN and ad-hoc networks, guiding users in these networks remains mostly an unexplored area of research. In this paper we present the concept of node-to-node guidance and introduce a method that can be used to implement it. This method relies on the computation of a local gradient in the neighborhood of the moving node. We named this protocol GUIDE-gradient, which is a GPS-free and infrastructure-free node-to-node guiding system. In this paper we also discuss how the guiding algorithm can be generalized to node-to-node guidance in multihop ad-hoc networks.     

Trust Based Intrusion Detection Technique to Detect Selfish Nodes in Mobile Ad Hoc Networks

The applications and protocols conceived for mobile ad hoc networks rely on the assumption of cooperation amongst the mobile nodes because of lacking infrastructure. All nodes have to spend their precious resources (e.g. battery power, memory, computational power, and network bandwidth) for routing and packet forwarding operations for other nodes, in a cooperative way in the network. However, there are some nodes that may intentionally turn themselves to behave selfishly in order to conserve their valuable resources. The selfish behaviour of such nodes drastically reduces the desired degree of cooperation amongst the mobile nodes. Over the course of time, the non-cooperative activities of, such selfish nodes would paralyze the normal functioning of the whole network. Therefore, these types of nodes should be detected and isolated from the network, as soon as they begin to exhibit their selfish behaviour. In this paper, a dynamic trust based intrusion detection technique is presented to detect and isolate the selfish nodes from the network, where the direct trust degree based on direct communication interactions and indirect (recommended) trust degree based on the neighbours’ recommendations are taking into account to accurately judge the selfishness nature of the nodes. The results obtained throughout the simulation experiments clearly show the feasibility and effectiveness of the proposed intrusion detection technique.     

Capacity Scaling in Ad Hoc Networks With Heterogeneous Mobile Nodes: The Super-Critical Regime

We analyze the capacity scaling laws of mobile ad hoc networks comprising heterogeneous nodes and spatial inhomogeneities. Most of previous work relies on the assumption that nodes are identical and uniformly visit the entire network space. Experimental data, however, show that the mobility pattern of individual nodes is usually restricted over the area, while the overall node density is often largely inhomogeneous due to the presence of node concentration points. In this paper we introduce a general class of mobile networks which incorporates both restricted mobility and inhomogeneous node density, and describe a methodology to compute the asymptotic throughput achievable in these networks by the store-carry-forward communication paradigm. We show how the analysis can be mapped, under mild assumptions, into a Maximum Concurrent Flow (MCF) problem over an associated Generalized Random Geometric Graph (GRGG). Moreover, we propose an asymptotically optimal scheduling and routing scheme that achieves the maximum network capacity.     

信号强度和运动向量结合的无线传感器网络移动节点定位

无线传感器网络的定位是近年来无线传感器网络研究的重要课题.本文首先介绍了无线传感器网络的来源、重要性以及无线传感器网络定位的分类.然后提出了一种全新定位算法,信号强度和运动向量结合的无线传感器网络移动节点定位,简称SSMV算法,在外围布置四个锚节点,得用信号强度和未知节点在运动中向量的变化,对锚节点在内的未知节点进行定位,并对该算法进行了仿真和总结.通过与凸规划法进行比较,仿真结果表明,该算法有更高的定位精度.     

A Fast Formation Flocking Scheme for a Group of Interactive Distributed Mobile Nodes in Autonomous Networks

Ubi-Com promises to provide a diversity of services at anytime and anyplace. The mobile nodes are envisioned to cooperate freely and move on a plane with the help of the efficient control and distributed coordination strategies. To achieve this goal, mobile nodes group communications in Ubi-Com is becoming increasing important and challenging. In this paper, we focus on the formation flocking in a group of autonomous mobile nodes. In the scenario, there are two kinds of nodes: the leader node and the follower nodes. The follower nodes are required to follow the leader node wherever it goes (following), while keeping a particular formation they are given in input (flocking). A novel scheme is proposed on the basis of the relative motion theory. Extensive theoretical analysis and simulation results have demonstrated that this scheme provides the follower nodes an efficient and timely method to follow the leader with the shortest path and the shortest time. In addition, the reported scheme is scalable in the sense that the processing load in each node is not increasing with more nodes in a group.     

用移动IP实现移动Ad hoc网与Internet的互联

移动IP是一种简单可扩展的全球Internet移动解决方案。本文介绍了移动IP和移动Ad hoc网络的融合技术,以实现移动Ad hoc网络与Internet的互联。     

Collaborative Polling based Routing Security Scheme to Mitigate the Colluding Misbehaving Nodes in Mobile Ad Hoc Networks

The recent advancements in the field of wireless communications makes the mobile devices to communicate with each other in a self organized manner without relying on stable infrastructure. It requires cooperation between the mobile devices in order to find routes between them when the nodes are not in the communication range of each other. The misbehaving node comes into existence due to scarcely available resources such as battery, bandwidth and computational power. When the nodes collude to misbehave then it further makes the routing process difficult due to frequent network partitioning and it also degrades the overall network throughput. This paper proposes a Collaborative Polling based Routing Security Scheme to detect and isolate the colluding misbehaving nodes in mobile ad hoc networks. The proposed system employs a timeout approach to detect the active neighbors in the neighborhood before monitoring the transmissions which involves it. It ensures that the false detection of a good node as a bad one has been greatly reduced which in turn decreases the send buffer drop because of the availability of alternate routes. The simulation result shows that the measured parameters such as packet drop ratio and malicious drop has been reduced due to the efficient detection and isolation of misbehaving nodes. This paper also presents an analytical and simulation results of the impact of node misbehavior.     

Spread-Spectrum Mobile Radio with Variable-Bit-Rate Speech Transmission

We describe a digital mobile radio system in which users experiencing poor transmission reduce the number of bits per second used for speech coding from 32000 to 28000. They do so in a manner that greatly reduces the binary error rate. The reduced error rate more than compensates for increased quantization noise. We predict two statistics of user satisfaction in a mobile radio service area: POW, the percentage of users experiencing poor or worse transmission, and GOB, the percentage good or better. In a typical environment the maximum number of users that can operate within a 20 MHz band with POW ≤ 5 percent is 137, compared to 91 users when everyone transmits 32 kbits/s. The modulation technique is FH-FSK (frequency hopped, frequency shift keying) and the digital code is embedded ADPCM (adaptive differential pulse code modulation), in the mobile radio service area, signal strength depends on distance from mobile unit to a central base station. There is slow (shadow) fading due to terrain and building variations and rapid (Rayleigh) fading due to multipath propagation. To predict user satisfaction we have combined three different analyses: 1) a theory of FH-FSK, 2) a theory of the signal-to-noise ratio statistics in mobile radio service areas, and 3) a model, based on computer simulations and subjective testing data, of the dependence of subjective speech quality on ADPCM transmission rate and binary error rate.     

Identification of Key Nodes in Microblog Networks

A microblog is a service typically offered by online social networks, such as Twitter and Facebook. From the perspective of information dissemination, we define the concept behind a spreading matrix. A new WeiboRank algorithm for identification of key nodes in microblog networks is proposed, taking into account parameters such as a user's direct appeal, a user's influence region, and a user's global influence power. To investigate how measures for ranking influential users in a network correlate, we compare the relative influence ranks of the top 20 microblog users of a university network. The proposed algorithm is compared with other algorithms — PageRank, Betweeness Centrality, Closeness Centrality, Out‐degree — using a new tweets propagation model — the Ignorants‐Spreaders‐Rejecters model. Comparison results show that key nodes obtained from the WeiboRank algorithm have a wider transmission range and better influence.     

Speech and Video Telephony Quality Characterization and Prediction of Live Contemporary Mobile Communication Networks

Quality of Service (QoS) characterization and prediction is of utmost importance in contemporary operating cellular communications networks. Measurements data of speech and video telephony have been collected using modern experimental equipment. More specifically, key performance indicators of radio, speech and video quality are evoked. The objective of our study is to critically investigate the performance of speech and video telephony at live cellular networks correlating significant QoS parameters from radio and the service side. Simple non-linear regression models are also proposed for speech and video quality prediction. Finally, the paper represents the splendid positive influences of the continuous performance evaluation for the optimization of the mobile networks. There are also briefly given guidelines for mobile networks benchmarking.     

SDN技术及其在移动通信网中的应用

提出移动分组域网关控制面进一步分离以及面向用户和业务的智能路由两种在移动核心网引入软件定义网络(SDN)技术的思路,对移动分组域架构的演进展开了进一步思考;分析了数据中心内部和跨数据中心网络中可能的SDN应用场景,预测了SDN短期应用的可能性;分析了网络服务虚拟化的应用场景和关键技术.     

OTN承载以太网业务方式的探讨

以太网技术的应用正在由局域网延伸到城域网甚至广域网中,相应的以太网带宽也逐渐增加,40 GE/100 GE标准都已在进行讨论.本文首先简单介绍了OTN技术,然后讨论并比较了已有GE/10 GE业务映射到0TN净荷中的可行方式及未来出现的40 GE/100 GE业务映射到OTN净荷中的可能方式.     

An Analytical Model for Wireless Sensor Networks with Sleeping Nodes

We consider a wireless sensor network whose nodes may enter the so-called sleep mode, corresponding to low power consumption and reduced operational capabilities. We develop a Markov model of the network representing: 1) the behavior of a single sensor as well as the dynamics of the entire network, 2) the channel contention among sensors, and 3) the data routing through the network. We use this model to evaluate the system performance in terms of energy consumption; network capacity, and data delivery delay. Analytical results present a very good matching with simulation results for a large variety of system scenarios, showing the accuracy of our approach