A Vehicular Ad-Hoc Networks (VANETs) is the technology that uses moving cars as nodes in a network to create a mobile network. VANETs turn every participating car into a wireless router, allowing cars of each other to connect and create a network with a wide range. VANETs are developed for enhancing the driving safety and comfort of automotive users. The VANETs can provide wide variety of service such as Intelligent Transportation System (ITS) e.g. safety applications. Many of safety applications built in VANETs are required real-time communication with high reliability. One of the main challenges is to avoid degradation of communication channels in dense traffic network. Many of studies suggested that appropriate congestion control algorithms are essential to provide efficient operation of the network. However, most of congestion control algorithms are not really applicable to event-driven safety messages. In this paper we propose congestion control algorithm as solution to prevent congestion in VANETs environment. We propose a complete validation method and analyse the performance of our congestion control algorithms for event-driven safety messages in difference congested scenarios. The effectiveness of the proposed congestion control algorithm is evaluated through the simulation using Veins simulator.

By considering the security flaws in cryptographic hash functions, any commitment scheme designed straight through hash function usage in general terms is insecure. In this paper, we develop a general fuzzy commitment scheme called an ordinary fuzzy commitment scheme (OFCS), in which many fuzzy commitment schemes with variety complexity assumptions is constructed. The scheme is provably statistical hiding (the advisory gets almost no statistically advantages about the secret message). The efficiency of our scheme offers different security assurance, and the trusted third party is not involved in the exchange of commitment.
The characteristic of our scheme makes it useful for biometrics systems. If the biometrics template is compromised, then there is no way to use it directly again even in secure biometrics systems. This paper combines biometrics and OFCS to achieve biometric protection scheme using smart cards with renewability of protected biometrics template property.

Mobile Ad hoc Network (MANET) is a collection of mobile users without any support of fixed infrastructure. The nodes in these networks have several constraints such as transmission power, bandwidth and processing capability. In addition to it an important parameter of interest is the residual battery power of the nodes. Conventional routing schemes do not take this aspect into consideration. Therefore this paper proposes a routing strategy that takes this aspect into consideration by modifying the Route Request (RREQ) packet of the Ad hoc On demand Distance Vector (AODV) routing protocol. The protocol chooses a threshold below which a node is not allowed to relay data/control packets. The results show a remarkable improvement in the value of Packet Delivery Ratio (PDR), throughput and at the same time the network lifetime is not affected.

In this paper, we focus on the network topological design for providing Quality of Service (QoS) in Next Generation Network (NGN) and propose an effective Ant Colony Optimization (ACO) algorithm to solve the capacitated minimum spanning tree (cMTS) problem in dynamic environment. To improve QoS of communication network with considering the network provisioning capability and dynamic environment, we formulate this problem with minimizing the communication cost (as a kind of performance measures for network's QoS). Our objective functions are determined by pheromone matrix of ants satisfies capacity constraints to find good approximate solutions of cMST problems. Numerical experiments show that our algorithm have achieved much better than recent researches.

There is an increasing research interest in solving routing problems in Wireless Sensor Networks (WSN) and most of the existing routing protocols for WSN consider homogeneous nodes wherein, all sensor nodes have the same capabilities in terms of sensing, communication and computation capabilities. However, deployment of a homogeneous sensor network may suffer from poor performance. In this paper, we present a novel QoS routing scheme that adaptively learns an optimal routing strategy, depending on multiple optimization goals. We base our approach on Ant Colony Optimization (ACO) technique which is insensitive to initial setting, thus ideal in the context of WHSNs. The key feature of the protocol is its ability to meet diverse QoS requirements posed by different kinds of traffic generated due to heterogeneous nature of nodes thus maximizing network performance and utilization. Experimental results suggest a significant gain in the performance of proposed protocol over AODV protocol.

In this paper, we propose a network model with energy heterogeneity. This model is general enough in the sense that it can describe 1-level, 2-level, and 3-level heterogeneity. The proposed model is characterized by a parameter whose lower and upper bounds are determined. For 1-level heterogeneity, the value of parameter is zero and, for 2-level heterogeneity, its value is (√5-1)/2. For 3-level of heterogeneity, the value of parameter varies between its lower bound and upper bound. The lower bound is determined from the energy levels of different node types, whereas the upper bound is given by (√5-1)/2. As value of parameter decreases from upper bound towards the lower bound, the network lifetime increases. Furthermore, as the level of heterogeneity increases, the network lifetime increases.

Wireless networks, in particular Mobile Ad hoc Networks (MANETs) have revolutionized the field of networking with increasing number of their commercial and military applications. Security on the other hand, is now an essential requirement for these applications. However, the limitations of the dynamic, infrastructure-less nature of MANETs impose major difficulties in establishing a secure framework suitable for such services. Security for MANETs is a dynamic area of research. Most of the traditional routing protocols proposed for MANETs are focused on routing only not on the security aspects. As in traditional wired networks, wireless networks also require security. Unlike the wired networks, where dedicated routers, servers control the network, in MANETs nodes act both as terminals and also as routers for other nodes. A popular mechanism to satisfy the security requirements is the Group Key Management in which the group key is to be shared by each group communication participant. But to establish and manage the group key efficiently imposes new challenges – especially in infrastructure less MANETs. The basic needs of such networks require that the group key schemes must demonstrate not only high performance but also fault-tolerance.

Wireless Sensor Networks (WSNs) incorporate smart antennas for information propagation to offer connected coverage with reduced interference. This paper presents an omni directional antenna assisted scheme for WSNs to reduce network redundancy besides offering connected coverage. The directivity of an omni directional antenna outfitted on a sink node is exploited to reduce network redundancy and at the same time the connectivity of sensor nodes with the sink node is retained. The relationship between lobe count, beam width, rotation angle and directivity of an omni directional antenna in context of sensor networks is also discussed. Simulation results show a significant reduction in overall network redundancy if the rotation angle of the omni directional antenna fitted on the sink node is minimized from 360° to 30°.