Mobile ad hoc networks (MANET) are collections of self-organizing mobile nodes with dynamic topologies and have no fixed infrastructure. MANET do not have centralized administration, here nodes act as both host as well as router and communicate by forwarding packets for each other in multi hop way, because of the fundamental characteristics like, the open medium, dynamic network topology,lack of centralized monitoring and management these networks are particularly vulnerable to various types of attacks. One of the routing protocol being used for wireless network is Ad hoc on demand distance vector (AODV).Black hole is one of the attack that is launched on AODV. In this attack, the attacker claims the shortest route to the destination and hinders the communication by dropping all the packets. In this paper, a new solution against the Black Hole attack is proposed. This paper demonstrates a timer based detection approach for identifying black hole node. In network layer we proposed a Timer based method to overhear the next node action. The simulation results using EXata-Cyber shows that in a dynamic network most of the malicious nodes can be detected and that results in an improved packet delivery ratio.

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Nowadays, optical fiber sensors are playing an important role in bio-sensing applications. Depending on the applications, suitable types of fiber sensors have been produced timely. The aim of these sensors is to provide better sensitivity and high detection capabilities. Thereafter, these tri-core fibers can be applied to sense various substances like salinity, glucose, stress, and temperature. This kind of sensing PCF was introduced by Philip Russell in 1991. In 1996, his group declared the first example of working PCF. Due to their unique properties, such types of fibers showed more impact in sensing applications and widely used in high compact sensitivity aids like temperature sensors, magnetic field sensors, pressure sensors, stress monitoring devices, and seawater salinity sensors. Apart from these sensing devices, the photonic crystal fibers-based sensors have been widely used in social terms and society-based applications. It includes various designs of single channel, semi channel, and multi channel sensors along with different materials. For example, the detection of glucose in human blood and stress level of human beings can be easily detected with such types of tri-core PCF. It is being found that sensitivity of glucose is observed at 19,007.17 nm/RIU with the use of sensor-based PCF. This sensitivity can be further increased by using Sagnac interferometer along with sensor-based PCF. With this, the sensitivity so observed is 22,120 nm/RIU.

This paper presents the results related to performance evaluation of 4-stage multiuser detector for asynchronous DS-CDMA system. To meet the real-time requirements for asynchronous multiuser detection, a bit streaming, parallel interference cancellation (PIC) cascade architecture is used. An asynchronous multiuser detection involves block-based computations and matrix inversions. The paper covers iterative-based suboptimal schemes that have been used to decrease the computational complexity, eliminate the need for matrix inversions, decreases the execution time, reduces the memory requirements by making use of joint estimation and detection process that gives better performance than the independent parameter estimation method. The stages of the iteration are cascaded and bits processed in a streaming fashion. The simulation has been carried out for asynchronous DS-CDMA system by varying two parameters, i.e., number of users and number of stages. The simulation results exhibit that system gives better performance at 3rd stage and the number of users decrease with increase in signal to noise ratio (SNR).