Browsing by Author "Segun, Popoola"

Now showing 1 - 4 of 4
  • Item
    Path Loss Predictions in the VHF and UHF Bands Within Urban Environments: Experimental Investigation of Empirical, Heuristics and Geospatial Models
    (Institute of Electrical and Electronics Engineers, 2019-06-01) Nasir, Faruk; Segun, Popoola; Bakinde, Surajudeen; Abdulkarim, Oloyede; Lukman A, Olawoyin; Mudathir, Akorede; Adulkader, Madugu; J.D, Morrow; Yinusa, Adediran
    Deep knowledge of how radio waves behave in a practical wireless channel is required for effective planning and deployment of radio access networks in urban environments. Empirical propagation models are popular for their simplicity, but they are prone to introduce high prediction errors. Different heuristic methods and geospatial approaches have been developed to further reduce path loss prediction error. However, the efficacy of these new techniques in built-up areas should be experimentally verified. In this paper, the efficiencies of empirical, heuristic, and geospatial methods for signal fading predictions in the very high frequency (VHF) and ultra-high frequency (UHF) bands in typical urban environments are evaluated and analyzed. Electromagnetic field strength measurements are performed at different test locations within four selected cities in Nigeria. The data collected are used to develop path loss models based on artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and Kriging techniques. The prediction results of the developed models are compared with those of selected empirical models and field measured data. Apart from Egli and ECC-33, the root mean squared error (RMSE) produced by all other models under investigation are considered acceptable. Specifically, the ANN and ANFIS models yielded the lowest prediction errors. However, the empirical models have the lowest standard deviation errors across all the bands. The findings of this study will help radio network engineers to achieve efficient radio coverage estimation; determine the optimal base station location; make a proper frequency allocation; select the most suitable antenna; and perform interference feasibility studies.
  • Item
    Reliability Study of Stand-alone Hybrid Renewable Energy Microgrids
    (Iran J Sci Technol Trans Electr Eng, 2018-10-18) Bakinde, Surajudeen; Faruk, Nasir; Segun, Popoola; Muhammad, Salman; Abdulkarim, Oloyede; Lukman A, Olawoyin; C.T, Calafate
    This paper proposed new indices for investigating the reliability of the microgrid at different levels. The microgrid used has been developed in DigSILENT software and is comprised of wind, solar, battery storage and a diesel generator. The software was used to observe the effect of system demand and the failure rate of each component at three indices levels. Different simulations had shown that an increase in the system demand affects average energy not supplied, EIC, and average customer curtailment index. Also, at load point, LPIC and load point energy not supply among others are sensitive to system demand. This work proposes a new approach to study the effect of network structure on the reliability of a microgrid. The proposed method employs the prioritization of component importance on microgrid configuration. The results obtained show that the contribution of components to the system’s reliability depends on the network structure. This could be used in identifying direction, priority, and upgrading and suggests the most efficient way to operate and maintain a microgrid.
  • Item
    Secure transmission in an unfriendly environment
    (Published by Elsevier BV, 2019-10-01) Lukman A, Olawoyin; Faruk, Nasir; Abdulkarim, Oloyede; Segun, Popoola; Temitayo, Adeniran; Bakinde, Surajudeen; Abdulkarim, Abubakar
    This work investigates and show the performance of destination assisted node in ensuring secure communication in a dual-hop broadcast system. The information transmission occurs between the transmitters which are assumed to be equipped with single antenna through a number of intermediate untrusted relays to the receiver in the presence of multiple passive eavesdroppers. This work assumes that there is no direct link between the transmitter and the receiver and hence, the relay node, receives either the information or noise signal at every transmission processes. Since the transmission occurs in a two-phase, the legitimate receiver is contributing a degrading noise to both the eavesdropper and relay node channels during the first phase while it receives information from the transmitter through the relay during the second phase. Simulation results are used to illustrate the performance of the proposed scheme.
  • Item
    State of the Art in Research on Optimum Design, Reliability and Control of Renewable Energy Microgrids
    (2018-10-01) Abdulkarim, Abubakar; Faruk, Nasir; Abdulkarim, Oloyede; LUkman A, Olawoyin; Segun, Popoola; Abdullateef, Ibrahim; Yinusa, Adeniran
    This paper has presented a comprehensive review in the area of microgrid from the design to implementation. The aim is to evaluate the current status, problems and research efforts toward realising functional microgrids in the power system. The expectations about microgrid are many; therefore the study is divided into three main sections. Recent advancements in the wind energy, solar energy and their future prediction are summarised. States of arts in optimum design of renewable energy microgrid are also investigated. In addition, critical literature review in the reliability analysis of microgrids consisting of renewable energy sources is also reported. Control of microgrids consisting renewable energy sources have been presented. Some examples of existing microgrids across the globe are critically reviewed. The work therefore recommends that energy planners and all stakeholders should consider environmental and regional difference in microgrids planning. Finally, future research areas and directions in these areas are highlighted.