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Item A low complexity greedy scheduler for multiuser MIMO downlink.(Wiley, 2014-02-01) Mureithi, George Maina; Mzyece, Mjumo; Djouani, KarimIt is widely believed that the implementation of multi-user multiple input multiple output (MU-MIMO) technology at the radio access portion of current and future wireless networks would positively impact on the performance of such networks especially in terms of system capacity. This however demands the design of efficient multi-user scheduling algorithms at the data link layer. In the case of packet data which is delay tolerant, there is more flexibility in the design of such multi-user scheduling algorithms. One such algorithm that is known to be throughput optimal is the greedy scheduler. For the downlink of a single input single output (SISO) system, the greedy scheduler serves the user whose channel maximizes the channel capacity at each transmission opportunity. By employing this algorithm to the down- link of a MU-MIMO system applying spatial multiplexing, the scheduler can allow a subset of active users whose channels are most favourable to transmit simultaneously. However, unlike in the SISO systems, the implementation of the classical greedy scheduler in MU-MIMO systems would result in very high computational complexity. This paper proposes a low complexity greedy scheduler for the MU-MIMO downlink and through simulations, demon- strates that the low complexity greedy scheduler performs close to the classical greedy scheduler but with minimum complexity.Item Energy harvesting techniques for sustainable underwater wireless communication networks: A review.(Elsevier Ltd., 2023-08-23) Alamu, Olumide; Olwal, Thomas O.; Djouani, KarimThe emergence of various underwater wireless communication systems has been on the rise due to increasing human activities in the marine environment. In underwater wireless communication networks (UWCNs), several communication devices, such as sensors and autonomous underwater vehicles (AUV) are interconnected to expand communication coverage, monitoring, information gathering, and surveillance. These devices operate on batteries, making their replacement and recharging difficult. Consequently, sustaining the operational lifetime of UWCNs is deemed a major challenge. This leads to the development of various energy harvesting (EH) techniques to perpetuate the power supply to underwater devices. In this paper, we present a review of various energy sources and EH techniques applicable to UWCNs. To achieve this, we classify the energy sources into various categories in order to establish the peculiarities of each source and the type of harvester applicable to each category. Based on this classification, we present discussions on various contributions of articles related to applications of EH techniques in UWCNs. In addition to various insights gained from the presented papers, we establish that energy harvesters based on triboelectric effect, piezoelectric effect, sediment microbial fuel cell, acoustic, and optical power transfer are suitable for low-power (milliwatt-order) consuming devices such as sensors. Also, for devices with high power consumption requirement, such as AUV, solar and inductive power transfer-based harvesters should be employed. Furthermore, we identify several technical challenges that should be taken into consideration during the planning and system design phases. Finally, we highlight open research areas that could further improve the EH and communication processes in UWCNs.Item A novel non-iterative based framework for quick dynamic assessment of wind energy dominated multi-machine power system.(Elsevier Ltd., 2023-08-05) Alayande, Akintunde Samson; Popoola, Olawale; Pam, Gyang PaulRenewable Energy Sources have considerably expanded in recent years to address the widening energy deficit in modern power systems. Integrating these sources raises significant concerns for power system management, with transient stability constraints of networks being one of the growing issues for engineers and researchers. In this paper, the impact of Doubly Fed Induction Generators integration is analyzed to examine the transient stability on two test models. A Coupling Strength Index formulated from Network Structural Characteristics Theory is explored to detect the weakest transmission line. This method identifies line 7 to 8 and 5 to 6 as the weakest line with coupling strength index of 0.02739 and 0.105158 for IEEE 9 and 39 bus system, respectively. The system’s transient stability is then investigated with and without the Doubly Fed Induction Generators, considering a three-phase short-circuit fault applied at the middle of the identified line. Several characteristics associated with the system such as generator speed, rotor angle, and electric power were investigated. The simulation was carried out using DIgSILENT Power Factory and the results indicate that the systems are negatively impacted by the integration of Doubly Fed Induction Generators.Item Energy harvesting techniques for sustainable underwater wireless communication networks: A review.(Elsevier Ltd., 2023-08-23) Alamu, Olumide; Olwal, Thomas O.; Djouani, kARIMThe emergence of various underwater wireless communication systems has been on the rise due to increasing human activities in the marine environment. In underwater wireless communication networks (UWCNs), several communication devices, such as sensors and autonomous underwater vehicles (AUV) are interconnected to expand communication coverage, monitoring, information gathering, and surveillance. These devices operate on batteries, making their replacement and recharging difficult. Consequently, sustaining the operational lifetime of UWCNs is deemed a major challenge. This leads to the development of various energy harvesting (EH) techniques to perpetuate the power supply to underwater devices. In this paper, we present a review of various energy sources and EH techniques applicable to UWCNs. To achieve this, we classify the energy sources into various categories in order to establish the peculiarities of each source and the type of harvester applicable to each category. Based on this classification, we present discussions on various contributions of articles related to applications of EH techniques in UWCNs. In addition to various insights gained from the presented papers, we establish that energy harvesters based on triboelectric effect, piezoelectric effect, sediment microbial fuel cell, acoustic, and optical power transfer are suitable for low-power (milliwatt-order) consuming devices such as sensors. Also, for devices with high power consumption requirement, such as AUV, solar and inductive power transfer-based harvesters should be employed. Furthermore, we identify several technical challenges that should be taken into consideration during the planning and system design phases. Finally, we highlight open research areas that could further improve the EH and communication processes in UWCNs.Item Development of a novel plane piezoelectric actuator using Hamilton’sprinciple based model and Hertz contact theory.(Elsevier B.V., 2014-07-06) M’boungui, G.; Semail, B.; Giraud, F.; Jimoh, A.A.A simple device based on friction coefficient control was designed as a solution to the lack of compact-ness and simplicity encountered in the number of force feedback interfaces. The structure comprises a64 × 38 × 3 mm copper-beryllium plate on which well-adjusted polarized piezoceramics are glued. The plate stands on four legs, each of which has a spherical end. By controlling the drive voltage, friction force may be varied as required by a user who moves the device on a flat surface, as he or she would do with a normal mouse. This adds the possibility of rendering simulated forces from objects manipulated on a PC screen. Friction forces obtained using Hertz contact theory compare well with the ones measured on an experimental setup, which demonstrate the validity of the approach with regard to force feedback application.Item An alternative algorithm for solving generation‐to‐load matching and loss allocation problems.(Wiley, 2017-01-21) Alayande, Akintunde S.; Jimoh, Adisa A.; Yusuff, Adedayo A.This paper presents an alternative approach of Inherent Structural Characteristics Theory (ISCT), for solving loss allocation to network participants as well as generation‐to‐load matching problems in a deregulated environment. The mathematical formulations of ISCT, based on the fundamental circuit theory laws, are revisited. A Generation‐to‐Load Allocation Coefficient (GLAC) matrix for solving generation‐to‐load allocation and network loss allocation to load problems, for efficient transmission pricing, is formulated. The allocation of real and reactive power contributions, by individual generator, required to serve the network demands is also determined on the basis of the GLAC matrix. Total network losses are determined and allocated to individual network loads based on GLAC matrix. The approach is demonstrated using the standard IEEE 30 bus network. The results obtained are compared with that obtained using graph theory approach based on the solved power flow. The comparison of the results shows that the ISCT approach is reasonable and it is a good signal, which could be useful for pricing of electricity by the market regulators.Item Design of fault-tolerant automotive gateway architecture using MC9S12XDP512 microcontroller device.(MDPI, 2023-08-10) Krishnamoorthy, Ramesh; Chokkalingam, Bharatiraja; Munda, Josiah LangeThe increasing number of electrical components and sensors in modern vehicles makes network design more challenging. The development of automotive electronics through multiple communication protocols bring out the importance of a hybrid network that is both optimal and fault tolerant. In order for a vehicle to communicate with electronic components like engine management systems, stability control units, braking systems, and door functions, a CAN (controller area network) is developed. In order to create a hierarchical vehicle network gateway for quality fortification and cost reduction of vehicles, the CAN and LIN (local interconnect network) are considered. This standardisation will reduce the variety of low-end multiplex solutions currently available for automotive electronics’ development costs, production rates, service fees, and logistics costs. The implementation of a gateway in these electronic devices is made possible with the proposed hybrid architecture. This system effectively shows the high-speed and low-speed applications relevant to crucial ECUs in the network by using two distinct CAN and LIN gateways to send sensor data between the ECUs (electronic control units).Item On the most suitable sites for wind farm development in Nigeria.(Elsevier Inc., 2018-05-08) Ayodele, T.R.; Ogunjuyigbe, A.S.O.; Odigie, O.; Jimoh, A.A.The increasing demand for energy and the need for clean and affordable energy in Nigeria have necessitated the need for renewable energy resource assessment and subsequent determination of suitable sites within the country. One of the promising renewable energy resources with good potentials of meeting the energy requirements is wind. One of the main challenges of wind power development in Nigeria is lack of scientific data for policy formulation and decision making that will aid the development of wind power utilization. The data presented in this article were obtained with proper evaluation of the wind resource while taking into consideration environmental, social, and economic factors. The information from the data could be useful for taking optimal site selection decision by the policy makers, government, engineers etc. This will ensure optimal investment and return on investment for wind farm developers.Item Selection and rating of the step-up transformer for renewable energy application.(SAIEE, 2020-06-01) Thango, Bonginkosi A.; Jordaan, Jacobus A.; Nnachi, Agha F.In the past decade, South Africa has acquired more renewable energy (RE) generation capacity than the rest of the Sub-Saharan countries. This development has led to increasing concerns about problems associated with electrical equipment connected with the RE technologies, especially in wind and solar. These RE technologies have intermittent generation profiles and are connected to non-linear loads. The fundamental electrical equipment including the step-up transformer, with respect to which, high harmonic losses, abnormal temperature rise, and gassing problems have been extensively reported within the last 10 years and remains a precedence for many Independent Power Producers (IPPs). A requirement of the step-up transformer is that IPPs are required to provide a technical schedule clarifying the harmonic and distortion content at the plant’s point of common coupling (PCC). A lack of this knowledge to the transformer manufactures thereof leads to under-designing or over-designing cases if the harmonic content has been underestimated or overestimated respectively. In hindsight, it may be beneficial for the Independent Power Producers and transformer manufactures to collaborate to assure the transformer design philosophy for the intended RE application is aligned with the technical requirements. In this paper, a method of de-rating the transformer when supplying non-sinusoidal loads is presented. In this method, the continuous power rating of the transformer is reduced to treat the additional losses as a result of harmonic penetration. Initially, a harmonic spectrum supplied by the IPP is used to calculate the transformer load and service losses. Secondly, the harmonic load spectrum is employed to compute derating factors ascribed to as “K-Factor” and “Factor-K”, indicating the amount of de-rating necessary for the transformer under study when serving the considered harmonic spectrum. Lastly, the thermal considerations under the harmonic spectrum are presented.Item Investigating the nanomechanical properties of polymer-graphene-titanium nitride nanocomposites for high strength application.(Elsevier B.V., 2023-09-01) Uyor, Uwa O.; Popoola, Abimbola Patricia I.; Popoola, Olawale M.In this work, hybrid graphene nanoplatelets (GN) and titanium nitride (TiN) were used as reinforcements to enhance nanomechanical properties of ultra-high molecular weight polyethylene (PE). The ternary nanocomposites were prepared by solvent mixing and melt-compounding processes. The nanomechanical properties of the developed nanocomposites was determined using nanoindenter. It was observed that PE-GN binaryn nanocomposites enhanced the nanomechanical properties, however, this was significantly pronounced with PEGN- TiN ternary nanocomposites. For instance, the hardness and elastic modulus increased from 171 MPa and 2.5 GPa for the pure PE to 282 MPa and 3.2 GPa for PE-2 wt %GN nanocomposite, which are about 65% and 28% increments at applied load of 100 mN respectively. While PE-2 wt%GN-20 wt% TiN ternary nanocomposite revealed hardness and elastic modulus increments of about 196% and 100% compared to the pure PE and 80% and 56% compared to PE-2 wt% GN binary nanocomposite. The enhanced nanomechanical properties is attributed to the uniform distribution and interlocking of the PE molecular chains by the presence of the hybrid GNTiN nanoparticles in the polymer matrix. The enhanced hardness, elastic modulus and other mechanical properties in this study are essential for advanced engineering applications where high mechanical features are required.Item Pseudocapacitive material for energy storage application: PEDOT and PEDOT:PSS(AIP Publishing., 2020-11-26) Adekoya, Gbolahan Joseph; Sadiku, Rotimi Emmanuel; Hamam, Yskandar; Ray, Suprakas Sinha; Mwakikunga, Bonex Wakufwa; Folorunso, Oladipo; Adekoya, Oluwasegun Chijoke; Lolu, Olajide Jimmy; Biotidara, Olusesan FrankThe total volume of solar energy reaching the earth in every second is equivalent to the total energy usage by the entire human race for three days. With this vast amount of clean energy freely available to humanity, there is still heavy dependence on fossil resources for energy. The major challenge with the use of fossil-based fuel is the generation of both land and atmospheric pollutants, which adversely affect the ecosystem. However, an essential requirement in transitioning from fossil energy to clean energy is the use of effective energy storage systems. Poly(3,4-ethylenedioxythiophene) (PEDOT) and poly (4-styrene sulfonate) (PSS) PEDOT:PSS is currently one of the highly researched semi-conducting polymers that form the vast and expanding literature on energy application. Owing to its high electrical conductivity, thermal stability, and film-forming ability, PEDOT and its derivatives are employed for pseudocapacitive storage applications. This review will present a detailed discussion on the synthesis, properties, and application of PEDOT:PSS for battery and ultracapacitors. Highlights on the recent development and outlook in the use of PEDOT and its derivatives for energy application will also be provided.Item Comparative study of graphene-polypyrrole and borophene-polypyrrole composites: molecular dynamics modeling approach(Growing Science Ltd., 2021-01-19) Folorunso, Oladipo; Hamam, Yskandar; Sadiku, Rotimi; Ray, Suprakas Sinha; Adekoya, Gbolahan JosephIn the search for the solution to energy storage problems, this study investigates the interfacial energy interaction and temperature stability of the composites made of polypyrrole-graphene-borophene (PPy-Gr-Bon) by using molecular dynamics simulations. From the calculated thermodynamics and interfacial energies of the system, comparisons between the ternary and the binary-binary systems were made. The materials in the entity show a good degree of temperature stability to a dynamic process at 300, 350, 400, and 450 K. Moreso, at 300 K, the interaction energy of PPy-Gr, PPy-Bon, and PPy-Gr-Bon are: -5.621e3 kcal/mol, -26.094e3 kcal/mol, and -28.206e3 kcal/mol respectively. The temperature stability of the systems is in the order of: PPy-Gr-Bon > PPy-Bon > PPy-Gr. The effect of temperature on the interaction energy of the systems was also investigated. The ternary system showed higher stability as the temperature increased. In addition, the radial distribution function computed for the three systems revealed that there is a strong, but non-chemical bonding interaction between PPy-Gr-Bon, Bon-PPy, and Gr-PPy. By considering the excellent mechanical properties of PPy-Gr-Bon and the already established high electrical conductivity and chemical stability of Gr, Bon and PPy, their composite is therefore suggested to be considered for the manufacturing of electrochemical electrodes.Item A mini-review of artificial intelligence techniques for predicting the performance of supercapacitors(Elsevier Ltd., 2022-05-18) Adekoya, Gbolahan Joseph; Adekoya, Oluwasegun Chijioke; Ugo, Ugonna Kingsley; Sadiku, Emmanuel Rotimi; Hamam, Yskandar; Ray, Suprakas SinhaSupercapacitors are used to store and release electrical charges like batteries and conventional capacitors. Unlike conventional capacitors, they have higher capacitance and power density, and they charge faster than batteries can. Supercapacitors are mainly classified as hybrid supercapacitors, pseudocapacitors, and electrochemical double-layer capacitors. To predict the application behaviour and optimization of supercapacitors, artificial intelligence, specifically machine language is utilized more recently. Models based on artificial intelligence are less complicated and maybe accurate enough. This paper identifies machine language models that have been employed to predict the supercapacitors’ performance.Item Application of DFT calculations in designing polymer-based drug delivery systems: An overview.(MDPI, 2022-09-19) Adekoya, Gbolahan Joseph.; Adekoya, Oluwasegun Chijioke.; Sadiku, Rotimi Emmanuel.; Hamam, Yskandar.; Ray, Suprakas Sinha.Drug delivery systems transfer medications to target locations throughout the body. These systems are often made up of biodegradable and bioabsorbable polymers acting as delivery components. The introduction of density functional theory (DFT) has tremendously aided the application of computational material science in the design and development of drug delivery materials. The use of DFT and other computational approaches avoids time-consuming empirical processes. Therefore, this review explored how the DFT computation may be utilized to explain some of the features of polymer-based drug delivery systems. First, we went through the key aspects of DFT and provided some context. Then we looked at the essential characteristics of a polymer-based drug delivery system that DFT simulations could predict. We observed that the Gaussian software had been extensively employed by researchers, particularly with the B3LYP functional and 6-31G(d, p) basic sets for polymer-based drug delivery systems. However, to give researchers a choice of basis set for modelling complicated organic systems, such as polymer–drug complexes, we then offered possible resources and presented the future trend.Item Quantum mechanical study of the dielectric response of V2C-ZnO/PPy ternary nanocomposite for energy storage application.(Springer, 2023-04-19) Ezika, Anthony Chidi.; Sadiku, Emmanuel Rotimi.; Adekoya, Gbolahan Joseph.; Ray, Suprakas Sinha.; Hamam, Yskandar.With the proliferation of electronic gadgets and the internet of things comes a great need for lightweight, affordable, sustainable, and long-lasting power devices to combat the depletion of fossil fuel energy and the pollution produced by chemical energy storage. The use of high-energy-density polymer/ceramic composites is generating more curiosity for future technologies, and they require a high dielectric constant and breakdown strength. Electric percolation and Interface polarization are responsible for the high dielectric constant. To create composite dielectrics, high-conductivity ceramic particles are combined with polymers to improve the dielectric constant. In this work, ternary nanocomposites with better dielectric characteristics are created using a nanohybrid filler of V2C Mxene-ZnO in a polypyrrole (PPy) matrix. Then, the bonding and the uneven charge distribution in the ceramic/ceramic contact area are investigated using quantum mechanical calculations. This non-uniform distribution of charges is intended to improve the ceramic/ceramic interface’s dipole polarization (dielectric response). The interfacial chemical bond formation can also improve the hybrid filler’s stability in terms of structure and, consequently, of the composite films. To comprehend the electron-transfer process, the density of state and electron localization function of the ceramic hybrid fillers are also studied. The polymer nanocomposite is suggested to provide a suitable dielectric response for energy storage applications.