Wireless sensor networks are being used for various applications for collection of heterogeneous data. Hotspot problem is major issue of concern that affects the connectivity of entire network along with decreasing lifetime of network. The focus in this paper is lies on optimizing the path followed by the mobile sink for collection of data. The proposed work aims at reducing the hotspot problem and increasing the lifetime. A trained neural network is used to select the best route to be followed by mobile sink. In the proposed work, the stop points are identified which allow the communication between the nodes and the movable sink. The experimental results of the work carried out show that tour length of the sink is greatly reduced and the network lifetime (number of rounds) is increased. Increased lifetime also handles the problem of hotspots.

It is common to hear that big or small organizations are moving to cloud computing for its scalability and cost savings. But, how do you decide which cloud provider to trust? Trust is a vital factor, especially for service oriented systems in the area of Information Technology and Security. Several issues have been raised by enterprises and individuals concerning the reliability of the cloud resources. In cloud computing, trust helps the consumer to choose the service of a cloud service provider for storing and processing their sensitive information. In this paper, a methodical literature analysis of trust management and existing trust models is presented to evaluate trust based on various QoS parameters. Key research issues and future research directions in existing literature are also suggested.

In this paper, we propose an enhanced approach based on first-hand reputation with allows to detected misbehavior node in Manet. The network's security is an important challenge in this kind of networks. The main objective of the misbehaving nodes in AODV routing protocol deletes all data packets that received thus, don’t transmit to their destination. In a reputation-based system, each node overhears the activity of its neighbors (transmit and receive) in first-hand or combined with second-hand. Our approach is composed of three-phase directly monitoring, calculating reputation value and node isolation. The reputation value is enhanced by the packet dropped due to other events such as overloading of queue and node availability. The node with a negative reputation will be isolated, and an alert packet will be distributed to neighboring nodes to inform, afterwards an improved local repair is started. The simulation results show that the proposed approach can detect and isolate a malicious node, which improves the packet delivery ratio and lowest increasing in the throughput, while reducing the success rate of the misbehaving nodes.

Vehicle-to-Vehicle (V2V) communication system is a network of vehicles that communicate with each other to exchange information. The environment between vehicles affect in the signals that travel from the transmitter to the receiver, subsequently, it is important to comprehend the underlying characteristics propagation channels. This paper discusses and models some of the key metrics such as path loss, power delay profile, and delay spread at 5.2 GHz carrier frequency. The analyses are presented for two scenarios; both of the transmitter and receiver are stationary and in moving case with considering the direction of the moving and the separation between the vehicles. Likewise, a probability of a presence of some impediments in between of the vehicles with various separations is considered. The achieved results show that path loss for many types of environments may be predicted with using the presented model channel Model and location of the obstacles is sensitive to the received signals.

A micro strip-fed printed, modified hexagonal slot ultra wideband antenna with a band notch function is presented as well as investigated in this paper. The basic antenna comprises a U-shape radiating patch on one side of the substrate and ground plane with modified hexagonal slot on the other side of the substrate. Proper alignment and use of a modified hexagonal slot gives additional resonances and much wider impedance bandwidth is obtained. To create a notched band for WiMAX, symmetrical L- shape parasitic stubs are embedded in the upper edge of the modified hexagonal slot of the ground plane. The proposed antenna operates over the frequency band from 2.71 GHz to 11.73 GHz with a band rejection from 3.27-4 GHz (for WiMAX).The proposed antenna is fabricated on a FR-4 substrate having a dielectric constant of 4.4 with an overall size of 28 x 28 x 1.6mm3. Parametric studies have been conducted by changing length, width and thickness of symmetrical L- shape parasitic stubs. Simulated results are in good agreement with measured results. Designed antenna exhibits good radiation, efficiency greater than 80% within the entire ultra wideband except for WiMAX frequency.