The use of antennas in various fields and applications is gaining much importance because of their growing advancements and numerous facilities. Due to their vast advantages, now wearable antennas are used in fields of personal healthcare, entertainment, military and many others. For the fabrication of wearable antennas, many aspects need special consideration in order to manufacture a safe system for the user. As the applications of wireless body centric communication with antennas has a great variability, so enhancements are made in the systems by integrating reconfigurable antennas in it. These antennas work better than the single installed antennas because of their adjustable parameters thus increasing the performance of whole system. This paper provides an overview of the existing antennas and their applications, in order to better understand ways in which the limitations associated with wearable antennas could be overcome in the future. Certain design challenges which occur during the fabrication of wearable antennas like safety, cost and tolerance in addition to the recent advancements in this field are discussed. Designing a particular antenna for body area network mainly depends upon the application of the user and the place of installation. To build a review about the reconfigurable antenna for body centric communication, 15 papers from the last 6 years are consulted which fall under the domain of wearable antennas. There is still a margin of improvement in this field and better technologies will be introduced in coming years which include precision medicine.

Spectrum Sensing (SS) is a critical operation in a Cognitive Radio (CR) network to identify spectrum hole thereby preventing licensed users from harmful interference for improving spectrum utilization. However, multipath effects in wireless channel such as multipath fading, shadowing and receiver uncertainty affect the sensing accuracy of CR resulting to high Probability of Missing (PM) that causes interference to Primary User (PU). Maximal Ratio Combining (MRC) technique which was one of the techniques used to solve this problem suffers hardware complexity resulting in high Sensing Time (ST). Therefore, in this paper, modification of MRC technique is carried out to reduce hardware complexity of conventional MRC thereby reducing ST. The modified technique consists of ‘L’ Secondary User (SU) antennas that received the multiple copies of Primary User (PU) signals over Nakagami-m fading channel. The received PU signals are made to passed through separate channel estimator and co-phased to avoid signal cancellation before been summed up. The resultant signa is then made to passed through single RF chain and MF. Output of MF is then used as input to Energy Detector (ED) to obtain the energy of the received signal. The obtained energy is compared with the set threshold to determine the status of spectrum. The modified MRC technique is incorporated with simulation model which consists of PU transmitter that processes the randomly generated data through some signal processing techniques for transmission. Mathematical expression of Probability of False Alarm (PFA) for the modified MRC technique is derived and used to set the thresholds at PFA of 0.01 and 0.05. The modified model is evaluated using PM, Probability of Detection (PD) and PT to determine the performance. The results obtained revealed that modified MRC gives higher PD, lower PM and PT values when compared with conventional MRC.

In this paper, the design and development of wideband microwave pyramidal absorbers for semi anechoic chambers has been presented. This work is carried out with the goal of simulating and fabricating the microwave absorber using conventional and newest material such as polyurethane to save the budget cost with security and reliability. The simulation of absorber is performed via Computer Simulation Technology (CST) for the microwave frequencies 1 GHz to 20 GHz. The outcomes of simulation proved good absorbing efficiency and better RCS reduction compared to traditional microwave absorber. The reflection level is less than -30 to -10 dB over the desired frequency range of 1 GHz ~ 20 GHz.

Multi-stage attacks are attacks executed in phases where each phase of the attack solely relies on the completion of the preceding phase.  These attacks are so intelligently designed that they are able to elude detection from most network instruction detection systems and they are capable of penetrating sophisticated defenses.  In this paper, we proposed and simulated a Bayesian Belief Network Model to predict Multi-stage Attacks with Malicious IP.  The model was designed using Bayes Server and tested with data collected from cyber security repository.  The model had a 99% prediction accuracy. 

This article investigates on developing a methodology for statistical channel modeling for 60 GHz Wireless Local Area Network (WLAN) system. The most significant characteristics of indoor 60 GHz propagation channels such as large scale propagation path loss, quasi-optical propagation nature, reflection, diffraction, shadowing effect, clustering nature of the channel, effective impact of polarization and necessity of steerable directional antennas are taken into account. This research work has focused on modeling of the 60 GHz WLAN system to estimate the RMS delay spread (RDS) considering both directional and non-directional antennas for residential indoor environment. RDS is a measure of communication channel delay and estimates fading characteristics. Multipath effects and channel deep-fade can be alleviated by minimizing the channel RDS. This research work analyses the RDS characteristics of a living room environment considering two different indoor channel model approaches. Here, the IEEE 802.11ad living room channel model and the Saleh-Valenzuela       (S-V) model are considered while developing channel impulse response as well as RDS. The investigations show that highly directional steerable antennas can effectively reduce the channel delay spread. A comparative study between the IEEE 802.11ad and the S-V models has also been performed in the later section.