Prediction of Speech Quality Based on Resilient Backpropagation Artificial Neural Network

The paper presents a system for monitoring and assessment the speech quality in the IP telephony infrastructures using modular probes. The probes are placed at key nodes in the network where aggregating packet loss data. The system dynamically measures speech quality and results are collected on a central server. For data analysis we applied four-state Markov model for modeling the impact of network impairments on speech quality, afterwards, the resilient back propagation (Rprop) algorithm was used to train a neural network. Information about the speech quality are displayed in the form of automatically generated graphs and tables. The proposed solution has been tested with selected codecs and further generalizes the already presented concepts of the speech quality estimation in the IP environment.

     

PEAL: Power Efficient and Adaptive Latency Hierarchical Routing Protocol for Cluster-Based WSN

In wireless sensor networks, one of the most important constraints is the low power consumption requirement. For that reason, several hierarchical or cluster-based routing methods have been proposed to provide an efficient way to save energy during communication. However, their main challenge is to have efficient mechanisms to achieve the trade-off between increasing the network lifetime and accomplishing acceptable transmission latency. In this paper, we propose a novel protocol for cluster-based wireless sensor networks called PEAL (Power Efficient and Adaptive Latency). Our simulation results show that PEAL can extend the network lifetime about 47% compared to the classic protocol LEACH (Low-Energy Adaptive Clustering Hierarchy) and introduces an acceptable transmission latency compared to the energy conservation gain.     

Cybersecurity Issues in Wireless Sensor Networks: Current Challenges and Solutions

The spectrum is a scarce resource and shall be used efficiently. It is observed that fixed spectrum allocation techniques, currently in use, may not be able to accommodate increased number of users trying simultaneously to access the network. Researches suggest that this problem of spectrum scarcity can be addressed by cognitive radio networks; which permits the dynamic use of spectrum. One of the basic requirements of dynamic spectrum access in cognitive radio network is spectrum handoff. There is an associated issue with frequent spectrum handoffs and that is of the ping-pong ect. The ping-pong ect is caused due to the motion of mobile users between the adjacent cells, thus, initiating unnecessary spectrum handoffs. The purpose of this study is to develop and analyse a system that has the ability to perform cient decision about the execution of spectrum handoffs and in turn reduce the chances of ping-pong ect. Therefore, a fuzzy logic based system has been developed in a cognitive radio WLAN and UMTS environment and handoff is investigated between primary and secondary users. Our proposed hybrid system uses a two-stage fuzzy logic controller to reduce the number of ping-pong handoffs. In the rst stage, the system is designed to control the power of SU and to avoid any interference to PU. In the second stage, the system is designed to take the decision to execute handoff.