Abm Shawkat Ali

Energy-Efficient Wireless MAC Protocols for Railway Monitoring Applications

Recent advances in wireless sensor networking (WSN) techniques have encouraged interest in the development of vehicle health monitoring (VHM) systems. These have the potential for use in the monitoring of railway signaling systems and rail tracks. Energy efficiency is one of the most important design factors for the WSNs as the typical sensor nodes are equipped with limited power batteries. In earlier research, an energy-efficient cluster-based adaptive time-division multiple-access (TDMA) medium-access-control (MAC) protocol, named EA-TDMA, has been developed by the authors for the purpose of communication between the sensors placed in a railway wagon. This paper proposes another new protocol, named E-BMA, which achieves even better energy efficiency for low and medium traffic by minimizing the idle time during the contention period. In addition to railway applications, the EA-TDMA and E-BMA protocols are suitable for generic wireless data communication purposes. Both analytical and simulation results for the energy consumption of TDMA, EA-TDMA, BMA, and E-BMA have been presented in this paper to demonstrate the superiority of the EA-TDMA and E-BMA protocols.

Prospects of solar energy in Australia

Today, more than 80% of energy is produced from fossil fuels that pollute the air and surrounding environments each and every day, creating global warming. Therefore it is time to think about alternative sources of energy to build a climate friendly environment. In contrast to fossil fuels, renewable energy offers alternative sources of energy which are in general pollution free, unlimited, and environmentally sustainable. This paper presents a feasibility study undertaken to investigate the prospects of solar energy for the climate similar to Australia so as to further investigate the impacts of renewable energy sources in existing and future smart power systems. The monthly average global solar radiation has been collected for twenty-one locations in Australia from the National Aeronautics and Space Administration (NASA). Hybrid Optimisation Model for Electric Renewable (HOMER), and Renewable-energy and Energy-efficient Technologies (RETScreen) computer tools were used to perform comparative analysis of solar energy with diesel and hybrid systems. Initially, total net present cost (NPC), cost of energy (COE) and the renewable fraction (RF) were measured as performances metrics to compare the performances of different systems. For better optimisation, the model has been refined with a sensitivity analysis which explores performance variations due to solar irradiation and electricity prices. Finally, a statistical analysis was conducted to select the best potential places in Australia that produce maximum solar energy.

Experimental and simulation study of the impact of increased photovoltaic integration with the grid

The abundance, availability, and climate-friendly characteristics of solar photovoltaic (PV) energy encourage nations around the globe to adopt it to assist in overcoming global warming as well as build a sustainable society for the future. The intermittent nature of solar energy generation and the associated power electronic inverters with connected consumer loads creates a number of potential challenges in integrating large-scale PV into the grid that affects power quality of the distribution networks. This paper investigates the impacts of varying PV integration into the grid through experimental and simulation studies. Initially, several experiments were conducted with varying PV penetration and load conditions using the Renewable Energy Integration Facility at CSIRO, Newcastle, Australia. Later, a simulation model was developed that mimics the experimental facility used at CSIRO to investigate the adverse impacts on integrating large-scale PV into the grid using the power system simulation software PSS Sincal. Experimental and simulation analyses clearly indicate that integration of PV into the grid causes power quality issues such as voltage instability, harmonic injection, and low power factor into the networks and the level of these impacts increases with the increase of PV penetration.

Non-Linearity Effects of an OFDM-ROF Link Employing RF Amplifier and EAM

In this paper, a close agreement between a developed analytical model and an experimental case is presented to analyze non-linearity effects in terms of adjacent channel power ratio (ACPR) for OFDM signal fed RF amplifier integrated with radio over fibre (RoF) link.