Survivability in Time-varying Networks

Time-varying graphs are a useful model for networks with dynamic connectivity such as vehicular networks, yet, despite their great modeling power, many important features of time-varying graphs are still poorly understood. In this paper, we study the survivability properties of time-varying networks against unpredictable interruptions. We first show that the traditional definition of survivability is not effective in time-varying networks, and propose a new survivability framework. To evaluate the survivability of time-varying networks under the new framework, we propose two metrics that are analogous to MaxFlow and MinCut in static networks. We show that some fundamental survivability-related results such as Menger's Theorem only conditionally hold in time-varying networks. Then we analyze the complexity of computing the proposed metrics and develop several approximation algorithms. Finally, we conduct trace-driven simulations to demonstrate the application of our survivability framework to the robust design of a real-world bus communication network

Rough set based QoS enabled multipath source routing in MANET

The single constrained Quality of Service (QoS) routing in Mobile Ad-hoc NETwork (MANET) is disastrous in consideration of MANET characteristics, inference, collision and link failure as it maintains a single path. The QoS enabled routing yields better packet delivery and maintains consistency among nodes in the network by incorporating multi-constrained and multipath routing. The Dynamic Source Routing (DSR) is best suited source routing algorithm to maintain multipath information at the source node, but performance degrades with larger number of mobile nodes. Multi-layer mechanism should be incorporated to maintain QoS metric information spreads across multiple layers of TCP/IP protocol stack. The proposed multipath QoS enabled source routing provides balanced routing by making use of all these features. The imprecise decision making strategy called Rough Set Theory (RST) is used at destination node for decision making. The Route REQuest (RREQ) messages coming from different routes are filtered by considering the QoS metrics of each and every route by making use of RST. The Route REPly (RREP) messages are generated and delivered to the source node for filtered RREQ messages. The proposed routing algorithm will reduce load on the network by reducing number of control messages exchanged for route establishment. This will evenly distribute load among all the nodes and it also avoid the scenarios like few nodes starved for resources. Finally, multipath routing always provides alternate routing option in case of route failure

A new splitting-based displacement prediction approach for location-based services

In location-based services (LBSs), the service is provided based on the users' locations through location determination and mobility realization. Several location prediction models have been proposed to enhance and increase the relevance of the information retrieved by users of mobile information systems, but none of them studied the relationship between accuracy rate of prediction and the performance of the model in terms of consuming resources and constraints of mobile devices. Most of the current location prediction research is focused on generalized location models, where the geographic extent is divided into regular-shape cells. These models are not suitable for certain LBSs where the objectives are to compute and present on-road services. One such technique is the Prediction Location Model (PLM), which deals with inner cell structure. The PLM technique suffers from memory usage and poor accuracy. The main goal of this paper is to propose a new path prediction technique for Location-Based Services. The new approach is competitive and more efficient compared to PLM regarding measurements such as accuracy rate of location prediction and memory usage

Cost Optimization Approach for MANET using Particle Swarm Optimization

This paper present the approach require to increase the QoS of MANET network using particle swarm optimization algorithm. To improve data communication between two nodes we propose an efficient algorithm for AODV protocol using PSO where instead of suppling all default parameter with default value of AODV protocol we try to provide selective parameters with optimum value so that overall requirement of control packet get decrease that in turn result in to increase quality of service parameters of MANET. For the enhancement of reliability and reduction of cost, node speed control mechanism is implemented using PSO, The given method which is use for simulation, reduces the overall loss of data and also make transmission effective. We have also tested the performance of network by changing data rates and the speed of the node