Department of Electrical and Computer Engieering

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Electromagnetic Scattering Computation Methods for very Small Spheroidal Dust Particles: Theory and Applications
(2013) Musa, Abdulwaheed
This paper discusses the effect of propagation of electromagnetic waves through a cloud of very small particles. The size of these particles is normally less than 0.2 mm in radius, much smaller than the microwave wavelength; therefore it is possible to avoid laborious computation by using approximations. In this work we have checked the Rayleigh theory (Rayleigh scatterer) against a full solution of Maxwell’s main equations through a Point Matching Technique (PMT). The agreement between Rayleigh approximations and PMT for these very small particles is found to be good. These results have been used in quantifying some telecommunication channel impairments.
Electromagnetic Waves Propagation in Dust Storms at Millimeter Wave Band
(2013) Musa, Abdulwaheed
The effects of dust storms on propagation of electromagnetic wave at millimeter wave band are investigated. The propagation at millimeter wave band is affected by dust particles by way of signal attenuation. Formula for evaluating the wave attenuation at higher frequencies in a dusty medium is therefore developed in this work. The formula is based on the complex forward scattering amplitude of spherical dust particles using Rayleigh method. Three conditions are set to validate the suitability of the method for the model. It is shown that the Rayleigh approximation is valid for determining the scattering of spherical dust particles for the particle sizes and frequency range considered. The wave attenuation expression is proposed in terms of wavelength, visibility and complex permittivity. Attenuation results obtained are compared with some already published results. It is found that the attenuation by the proposed formula and the published formulae show close agreement. Attenuation in dry dust is only significant when the visibility becomes severe or at lower millimetric wave bands.
Genetic Algorithm Based Routing Algorithm for Packet Switching Network
(International Journal Of Electrical, Electronics and Computer Systems (IJEECS), 2014) Ogunbiyi, O., & Ahmed, W. A.
The distributed nature of routers in a packet switching network (PSN) and the need for them to send packet to one another following an optimal path make routing algorithm a necessity. In this paper, genetic algorithm (GA) is proposed to solve routing problem in a PSN. Computer simulation showed that GA approach obtain a result similar to Dijkstra’s algorithm (used in routing information protocol (RIP)) but with some improvement. The GA technique finds the optimal path between any source and destination nodes in a network. The network may be simple or complex, such that a feasible path or optimal path seems intractable. The developed technique was able to determine an entire route right from the source node, quick adaptation to changes in the network. It can also handle a numerous number of different constraints in the network. The binary coding used will also make it easier to implement in hardware.
Reliability Analysis of a 3-Machine Power Station Using State Space Approach
(Int. Journal of Engineering Research and Applications, 2014) Wasiu Akande Ahmed, Olalekan Ogunbiyi
With the advent of high-integrity fault-tolerant systems, the ability to account for repairs of partially failed (but still operational) systems become increasingly important. This paper presents a systemic method of determining the reliability of a 3-machine electric power station, taking into consideration the failure rates and repair rates of the individual component (machine) that make up the system. A state-space transition process for a 3-machine with 23 states was developed and consequently, steady state equations were generated based on Markov mathematical modeling of the power station. Important reliability components were deduced from this analysis. This research simulation was achieved with codes written in Excel®-VBA programming environment. System reliability using state space approach proofs to be a viable and efficient technique of reliability prediction as it is able to predict the state of the system under consideration. For the purpose of neatness and easy entry of data, Graphic User Interface (GUI) was designed.
Review and Assessment of Electromagnetic Wave Propagation in Sand and Dust Storms at Microwave and Millimeter Wave Bands – Part I
(2014) Musa, Abdulwaheed
Electromagnetic wave propagation in arid and semi-arid regions is influenced by sand and dust storms. Meagre information has hitherto been reported as to the effect of storms on telecommunication systems operating in such regions. This paper presents a survey of current understanding of the wave propagation during storms. In this first part of the review—Part I, detailed parametric assessment of some electrical and mechanical properties affecting wave propagation in sand and dust storms is given. The second part of the review—Part II describes the principle of approach and technology adopted for the investigation highlighting both strengths and drawbacks. The results demonstrate that most authors have calculated signal attenuation effect, revealing that it is not very significant unless during severe storms. A few papers indicate the possibility of more significant cross polarisation. Part I explicitly gives an account of the sand and dust storms’ phenomenon, reviews the storms’ parameters affecting electromagnetic wave propagations and discusses the microwave and millimeter wave bands.
Review and Assessment of Electromagnetic Wave Propagation in Sand and Dust Storms at Microwave and Millimeter Wave Bands – Part II
(2014) Musa, Abdulwaheed
Suspended particles in the atmosphere during sand and dust storms have numerous consequences on electromagnetic wave propagation in arid regions. The electromagnetic wave signal may suffer attenuation and cross polarization upon encounter with the suspended particles. However, meager information has hitherto been reported about effect of storms on the telecommunication systems operating in such regions. This paper presents a survey of current understanding of the electromagnetic wave propagation in sand and dust storms. A review of the literature covering electromagnetic scattering theory and applications is given. The review describes the principle of approach and technology adopted for the investigation highlighting both strengths and drawbacks. Detailed parametric assessment of the effects of storms on wave propagation as it concerns signal attenuation and cross polarization is also carried out. The results demonstrate that most authors have calculated the attenuation effect, revealing that it is not very significant unless very high suspended dust densities are assumed (i.e., during severe sand and dust storms). A few papers indicate the possibility of more significant cross polarisation. The obvious gap in knowledge of this field is finally also clearly established.
A Complexity Metric for Multi-Paradigm Programming Languages
(International Journal of Emerging Technology and Advanced Engineering, 2014-04-22) Olabiyisi S. O.; Omidiora E. O.; Balogun M. O.
Software complexity metrics are used to measure variety of software properties such as cost, effort, time, maintenance, understanding and reliability. Most of the existing metrics considered limited factors that affect software complexity, but do not consider the characteristics of multi-paradigm languages. In this work, a Multi-paradigm Complexity Metric (MCM) for measuring software complexity was developed for multi-paradigm codes. Multi-paradigm languages that were used in this work combine the features of procedural and object oriented paradigms, therefore this research began with investigation of factors that affect the complexity of procedural code, thereafter with a more modern approach, the research was further extended by adding object oriented features, so that the developed metric could be used not only for procedural code, but also either object oriented codes or in more general meaning for multi-paradigm codes. The developed metric was then applied on sample programs written in most popular programming languages such as Python, Java and C++, and was further evaluated with other existing complexity metrics like effective line of code (eLOC), cyclomatic complexity metric and Halstead complexity measures. The study showed that the developed complexity metric have significant comparison with the existing complexity metrics and can be used to rank competitive programs and difficulties of various modules.
Mobile AntNet Routing for Mobile Ad hoc Network
(Journal of Electronics and Communication Engineering (IOSR-JECE), 2015) Javeed Basha Haroon, Abdulkadir Ahmed, Olalekan Ogunbiyi
Routing in a Mobile Ad hoc Network (MANET) still pose great challenges which need to be addressed. Whenever a routing algorithm is developed, it should address the need of improving the quality of service (QoS) requirements, these requirements ranges from throughput, less overhead, packet loss, security etc. This paper focus on designing a nature inspired routing algorithm called the Mobile AntNet for Mobile Ad hoc network. Much of the previous implementations of this algorithm have been revolving around the fixed networks and improving the QoS for fixed networks. The AntNet algorithm was implemented in mobile ad hoc network using NS-2.34 simulator, the implemented algorithm was compared with other traditional routing algorithms in terms of node transmission range, node mobility, number of nodes and node failure. Multiple simulations were performed to obtain a statistical output by varying the different simulation parameters and graphs were plotted against three important performance metrics: throughput, routing overhead and end-to-end delay. Simulation result shows the performance of the designed algorithm in terms of throughput, packet loss and node failure.
Optimal Data Collection from a Network using Probability Collectives (Swarm Based)
(International Journal of Research in Engineering and Science, 2015) Abdulkadir Ahmed, Olalekan Ogunbiyi, Tahir Aduragba
This paper contains the implementation of the BeeAdhoc algorithm for data routing in mobile Ad-Hoc Network (MANet). The algorithm was inspired by the foraging behaviour of honey bees and its implementation mimics this behaviour. The integration was done on Network Simulator version 2 (NS-2.34) where different scenarios were considered in comparison with other existing state-of-the-art routing algorithms that have been implemented in the chosen simulator. The comparison was carried out between DSR, DSDV, AOMDV which are all multipath routing algorithms as the BeeAdhoc; this gave a better insight to the different behaviour of the algorithms on a common application environment. Throughput, end-to-end delay and routing overhead constitute the indices used for the performance evaluation. Experimental results showed the best performance of BeeAdhoc over, DSDV and AOMDV algorithms.
Harmonic Analysis in a 33-kV Distribution Network: A Case Study of Island Business District
(IEEE-Africa, 2015-06-01) L.M. Adesina; O.A. Fakolujo
Distribution Line Network harmonic investigation has become an important issue in electric power systems since the increased use of power electronic devices and equipment sensitive to harmonics, which in turn, has increased the number of adverse harmonic-related events. The power quality problem and the means of keeping it under control is a growing concern. Due to the connection of nonlinear loads in a 33kV distribution network, power quality issues have been raised and have resulted in widespread waveform distortion. This paper makes use of the Busbar voltage solutions obtained from a power flow study on the Eko Electricity Distribution Company’s 33kV network and they are used as the base data for the harmonic analysis. A distribution line model was formulated. MATLAB/Simulink was used to simulate this modeled network for each distribution line of the power system network considered. This simulation was achieved through the application of sending and receiving end busbar voltages already obtained from the power flow study. The harmonics observed on each distribution line at various scenarios of load/feeder restoration and their characteristic impedance magnitudes/frequency are all presented. Necessary discussions on the harmonic results are also presented.
Harmonic Mitigation on a 33kV Distribution Line using Passive Filters
(IEEE-Africa, 2015-09-01) L.M. Adesina; O.A. Fakolujo
The use of modern power electronic devices in circuits has made ‘power quality’ an increasingly important factor in the planning of both transmission and distribution systems. These devices are nonlinear loads such as office equipment like Central Processing Units (CPU), Plotters, etc., and most electronic home appliances such as Television, Video players, etc., that generate distorted harmonic currents and voltages, which get injected into the power system and leads to ineffective operation of the system. The Harmonic mitigation scheme is therefore imperative in the design and planning of a power system network. Consequently, this paper presents the control of harmonics in a 33kV Distribution line by using passive filters – a case of RLC and LC filters in both single and cascaded configurations were examined in order to study the net effects of their application in a distribution line. It involves the use of the distribution line (case study) results obtained from previous studies on power flow and harmonic analysis of the overall network that contains the distribution line of the case study. These results serve as source data for this research. Only a distribution line of the network was used as a test case. The harmonic mitigation analysis was carried out using MATLAB/Simulink platform. The simulation results of mitigation harmonics are presented. Conclusions and necessary recommendations for future research are also discussed.
Determination of Total Harmonic Distortion (THD) on a 33-kV Distribution Network: A Case Study of Island Business District
(University of Nigeria Press Ltd, University of Nigeria, Nsuka., 2015-10-01) L. M. Adesina; O. A. Fakolujo
Modern day AC power systems are proliferated by the introduction of several kinds of nonlinear loads which generate harmonics in a power system and this has a cumulative negative effect on power quality. Examples of nonlinear loads are power electronic devices, which cause distortion of voltage and current waveforms and consequently create Some harmonics within the power system. This paper presents the estimation of Total Harmonic Distortion (THD) of the Distribution lines in the 33kV distribution network of Island Business District, Eko Electricity Distribution Plc, taken as a case study using a set of busbar voltage results, obtained from previous studies on power flow and harmonic analyses of each time of the 33kV feeder restoration. The harmonics time of the 33kV feeder restoration. The harmonics and their impedances on each line at the scenario time of the 33kV feeders restored are presented. The estimated THD of each line and the overall network average THD are also presented.
Determination of Power System Losses in Nigerian Electricity Distribution Networks
(IJET Publications UK, 2016-09-01) Adesina, L. M.; Ademola Abdulkareem
Nigerian Electric Power Utilities face epileptic power supply due to poor generation level. The available power is characterised with high losses of Aggregate Technical and Commercial (ATC) or Total network losses. These losses have serious effects on the quality of power delivered to customers and adverse effect in meeting the expected revenue targets. Technical losses are caused by network impedance due to current flowing in the network and auxiliary supplies. Whereas non-technical losses are caused by several factors which include, energy theft, unbilled accounts, non-payment of customers, estimated customer accounts etc. This paper presents analysis of some selected power system network for estimation of total network or ATC losses and determination of network technical losses (TL) using power flow analysis. From the results of ATC losses and TL calculations, a total network non-technical loss (NTL) is determined.
Using Artificial Intelligence to Predict Animal Behaviour in Food Webs
(Transactions on Machine Learning and Artificial Intelligence, 2017) Aduragba, Tahir; Ahmed, Abdulkadir; Jimada-Ojuolape, Bilkisu; Ajani, Ayodeji; Adedoyin, Yinka
Overfishing of species in the marine life has caused oceans to become deserts at a fast pace. The population of specific species such as Cod and Haddock has reduced over the years. This has affected countries that hugely depend on them as a source of food. This study used Dynamic Bayesian Network (DBN) to predict animal behaviour in a food web. Two independent biomass surveys from the North Sea were used to learn predictive models and test them on the Northern Gulf Ocean. The resulting predictive model is expected to unveil useful information about what affects the population of fishes in the Northern Gulf Ocean. In addition, the predictive model was used to make predictions into the future about the effects of tampering with the population of specific species of fish in the same region. The focus was on the Cod species in the George’s Bank in relationship to species network in their food web. Looking at their biomass states and the effects it has on the hidden dependence when there is a change in their biomass states. Also, the different predictive models were used to evaluate species in the George’s Bank based on their performance. The result from the experiment shows that there is a hidden dependence, which is responsible for the collapse of species (Cod); due to the temperature or salinity of the ocean.
Automatic Generation of Root Locus Plots for Linear Time Invariant Systems
(Nigerian Journal of Technology (NIJOTECH), 2017) Durutoye, N., & Ogunbiyi, O.
Design and analysis of control systems often become difficult due to the complexity of the system model and the design techniques involved. This paper presents the development of a Tools Box in Microsoft Excel for control engineers that uses root locus as a time domain technique for system design and analysis. The Tool Box can also serve as a computer-aided graphical analytical tool for trainers. The work was done in two phases: the first phase is the development of programmable algorithms for root locus using the angle condition and bisection method while the second phase is the implementation of the developed algorithms. The implementation was done using Microsoft Excel (R) Visual Basic Application (VBA). Results of simulations for different systems show the potential of the Tool Box as an alternative for other software package and the ease of using it on the readily available Microsoft Excel environment.
A Study of Energy Conversion at the Jebba Hydroelectric Power Station
(IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017) Thomas C. T., Akorede M. F., Ogunbiyi O., Olufeagba B. J., & Samuel S. J.
Hydroelectric power significantly contributes to the national power grid of Nigeria. This paper examined the extent of utilization of the energy supplied into each of the turboalternators at the Jebba Hydroelectric Power Station (JHEPS), Nigeria and suggests a corrective culture to be employed for improved efficiency. The basic principle of a hydropower scheme and its conversion considerations were highlighted. The daily discharge, Q, in cumecs and the power generated, P, in MW at JHEPS over a decade period (2005 – 2014) were analyzed using codes and scripts of Microsoft EXCEL-VBA. Jebba hydroelectric power station is one of the three major hydropower stations in Nigeria and the potential is just beginning to be exploited. The stochastic distribution pattern of the station is also presented for further analysis of failure and repair of the station. The conversion behavior of each unit was found to be linear and all have a value greater than 0.5 on a scale of 0.00 to 1.00. Turbo-alternator (TA) unit 1 was found to have the highest conversion characteristic of 0.9951, while unit 4 was the least at 0.6884. However unit 6 was exempted in this analysis as it was not in use during this period. The paper also gave an insight into the effective operating head of each TA, the paper also suggests the corrective measure to employ for each turbine.
Total Harmonic Distortion (THD) in a Short Distribution Line of Varying Busbar Loads
(International Academic Institute for Science and Technology, 2017-01-01) Adesina Lambe Mutalub
In Electric Power Systems, attention is being focused on poor power quality issues which, in most cases, is caused by non-linear loads connected to the network. This often leads to waveform distortion. Consequently, harmonics at various electrical equipment that are connected to the power system are created. At this condition, the current or voltage Total Harmonic Distortion (THD) values violates the limits specified by IEEE 519-1992. This paper presents an investigation into the Total Harmonic Distortion of a short Distribution line (DL) with varied restoration energy in Megawatts. The distribution line of case study (Alagbon - Alagbon local) is between Alagbon 2 X 60 MVA, 132/33kV Transmission station and Alagbon local 2 X 15 MVA, 33/11kV Injection station, both within the same perimeter fence and located in Lagos, Nigeria. An algorithm as well as a Model circuit were developed and presented. This algorithm was applied to the developed Model circuit for Harmonic simulation using the MATLAB/Simulink platform. The resulting harmonic (second harmonic) at varying Busbar loads remained the same as shown in the results presented. Necessary discussions were made with conclusions drawn accordingly.
Effect of Capacitor Bank Installation in a Medium Voltage (MV) Substation
(International Institute for Science, Technology and Education (IISTE), 2017-01-01) Adesina, Lambe Mutalub; Ebere Iheanyichukwu
Several medium voltage substations, often called 33/11kV injection substations in Nigeria, are being run in electric utility companies without installing capacitor banks. Research has shown that the inclusion of capacitor bank improves system power factor and efficient running of the power system. This paper presents a brief description of the theory of power factor and its importance in achieving power system control and stability. Possible implications of substations without capacitor bank installations were also itemised. A schematic diagram of Ajangbadi 2X15MVA 33/11kV injection substation in Eko Electricity Distribution Company, Nigeria, is presented as a case study. A flowchart of the algorithm used to determine substation and network load parameters was developed and implemented. All results obtained and the necessary conclusions are presented.
Comparative Performance Evaluation Of Open Shortest Path First, OSPF And Routing Information Protocol, RIP In Network Link Failure and recovery cases
(2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017-05-20) Ayodeji Akeem Ajani; Bilkisu Jimada Ojuolape; Abdulkadir A. Ahmed; Tahir Aduragba; Balogun Monsurat
The effect of Network link failure is undesirable which necessitated redundant links for reliability. This implies that operations are switched between links in case of failure. In the modern world where speed matters, it is important to investigate how quickly different routing protocols, in this case, Open Shortest Path First, OSPF and Routing Information Protocol, RIP recovers in case of link failure in a mesh topology. The research was simulated using OPNET. It was modelled after the University of Salford main campus, using three of its building, Newton, Peel and CW library. There were several links in between the buildings. There network was configured for the two routing protocols in different scenarios to test for their performance in case of single and multiple link(s) failure and recovery. It was observed that RIP converges faster (11.21s) than OSPF (53.06s) at the initial stage of the network in all cases. However, OSPF converges faster (Average of 5s – link failure, Average of 15s – Link recovery) than RIP (Average of 18.57s- link failure, Average of 18.28s – link recovery) in both single and multiple link(s) failure/recovery scenarios.Therefore, based on the performance comparison, OSPF should be used in a network prone to frequent link failure as it performs better in this situation. However, RIP would be preferred
Assessment of Failure and Repair Behaviours of the Jebba Hydroelectric Power Station
(ELEKTRIKA- Journal of Electrical Engineering, 2018) Thomas, C. T., Ogunbiyi, O., Akorede, M. F., & Olufeagba, J. B.
Nigeria power generation is circa 4000 MW as at October 2016, this is far less than the national required value. Jebba Hydroelectric Power Station (JHEPS) is one of the three major hydropower stations in the country which its maximum average generation value is still less than the rated value of 578.4 MW. This paper presented some basic concepts of analysis of failure and repair. An algorithm was set up to extract the contiguous set of up-times and down-times to determine time-tofail (TTF) and time-to-repair (TTR) events, these events were analyzed for stochastic study. It was observed that the longest up time was 262 days and seen in turbo-alternator unit five, while the shortest was zero day and seen in the entire units except that of unit two. The longest downtime was 133 days and seen in the turbo-alternator of unit one, the least time-to-repair is a day and common to all the units. The frequency distributions for both TTF and TTR showed that 79% of TTF events and 57% of TTR events are distributed in the first 2 classes

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