Olasupo Opeyemi Ajayi

Dr. Olasupo Opeyemi Ajayi

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 May 2022 in IEEE Access
Verified
Journal Article
Open access
OAOlasupo Opeyemi Ajayi
Olasupo Opeyemi Ajayi
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
HMHloniphani Maluleke
Hloniphani Maluleke
ZGZaheed Gaffoor
Zaheed Gaffoor
NJNebo Jovanovic
Nebo Jovanovic
KPKevin Pietersen
Kevin Pietersen
Water is a fundamental requirement for human, animal, and plant survival. Despite its importance, quality water is not always fit for drinking, domestic and/or industrial use. Numerous factors such as industrialization, mining, pollution, and natural occurrences impact the quality of water, as they introduce or alter various parameters present therein, thus, affecting its suitability for human consumption or general use. The World Health Organization has guidelines which stipulate the threshold levels of various parameters present in water samples intended for consumption or irrigation. The Water Quality Index (WQI) and Irrigation WQI (IWQI) are metrics used to express the level of these parameters to determine the overall water quality. Collecting water samples from different sources, measuring the various parameters present, and bench-marking these measurements against pre-set standards, while adhering to various guidelines during transportation and measurement can be extremely daunting. To this end this study proposes a network architecture to collect data on water parameters in real-time and use machine learning (ML) tools to automatically determine suitability of water samples for drinking and irrigation purposes. The developed monitoring network is based on LoRa and takes the land topology into consideration. Results of simulations done in Radio Mobile revealed a partial mesh network topology as the most adequate. Due to the absence of large and open datasets on drinking and irrigation water, datasets usable for training ML models were developed. Three ML models -Random Forest (RF), Logistic Regression (LR) and Support Vector Machine (SVM) were considered for the water classification and results obtained showed that LR performed best for drinking water, while SVM was better suited for irrigation water. Recursive feature elimination was then combined with the three ML models to reveal which of the water parameters had the greatest influence on the classification accuracies of the respective model.

21 June 2019 in Sensors
Verified
Journal Article
Open access
PDF file
KMKun Ma
Kun Ma
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
CNClement Nyirenda
Clement Nyirenda
OAOlasupo Opeyemi Ajayi
Olasupo Opeyemi Ajayi
The internet of things (IoT) and cloud computing are two technologies which have recently changed both the academia and industry and impacted our daily lives in different ways. However, despite their impact, both technologies have their shortcomings. Though being cheap and convenient, cloud services consume a huge amount of network bandwidth. Furthermore, the physical distance between data source(s) and the data centre makes delays a frequent problem in cloud computing infrastructures. Fog computing has been proposed as a distributed service computing model that provides a solution to these limitations. It is based on a para-virtualized architecture that fully utilizes the computing functions of terminal devices and the advantages of local proximity processing. This paper proposes a multi-layer IoT-based fog computing model called IoT-FCM, which uses a genetic algorithm for resource allocation between the terminal layer and fog layer and a multi-sink version of the least interference beaconing protocol (LIBP) called least interference multi-sink protocol (LIMP) to enhance the fault-tolerance/robustness and reduce energy consumption of a terminal layer. Simulation results show that compared to the popular max–min and fog-oriented max–min, IoT-FCM performs better by reducing the distance between terminals and fog nodes by at least 38% and reducing energy consumed by an average of 150 KWh while being at par with the other algorithms in terms of delay for high number of tasks.

15 July 2022 in Hydrology
Verified
Journal Article
Open access
PDF file
ZGZaheed Gaffoor
Zaheed Gaffoor
KPKevin Pietersen
Kevin Pietersen
NJNebo Jovanovic
Nebo Jovanovic
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
TKTOB KANYERERE
TOB KANYERERE
GWGift Wanangwa
Gift Wanangwa
Machine learning and deep learning have demonstrated usefulness in modelling various groundwater phenomena. However, these techniques require large amounts of data to develop reliable models. In the Southern African Development Community, groundwater datasets are generally poorly developed. Hence, the question arises as to whether machine learning can be a reliable tool to support groundwater management in the data-scarce environments of Southern Africa. This study tests two machine learning algorithms, a gradient-boosted decision tree (GBDT) and a long short-term memory neural network (LSTM-NN), to model groundwater level (GWL) changes in the Shire Valley Alluvial Aquifer. Using data from two boreholes, Ngabu (sample size = 96) and Nsanje (sample size = 45), we model two predictive scenarios: (I) predicting the change in the current month’s groundwater level, and (II) predicting the change in the following month’s groundwater level. For the Ngabu borehole, GBDT achieved R2 scores of 0.19 and 0.14, while LSTM achieved R2 scores of 0.30 and 0.30, in experiments I and II, respectively. For the Nsanje borehole, GBDT achieved R2 of −0.04 and −0.21, while LSTM achieved R2 scores of 0.03 and −0.15, in experiments I and II, respectively. The results illustrate that LSTM performs better than the GBDT model, especially regarding slightly greater time series and extreme GWL changes. However, closer inspection reveals that where datasets are relatively small (e.g., Nsanje), the GBDT model may be more efficient, considering the cost required to tune, train, and test the LSTM model. Assessing the full spectrum of results, we concluded that these small sample sizes might not be sufficient to develop generalised and reliable machine learning models.

14 April 2021 in Sensors
Verified
Journal Article
Open access
PDF file
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
OAOlasupo Opeyemi Ajayi
Olasupo Opeyemi Ajayi
HMHloniphani Maluleke
Hloniphani Maluleke
Recently, vast investments have been made worldwide in developing Cyber-Physical Systems (CPS) as solutions to key socio-economic challenges. The Internet-of-Things (IoT) has also enjoyed widespread adoption, mostly for its ability to add “sensing” and “actuation” capabilities to existing CPS infrastructures. However, attention must be paid to the impact of IoT protocols on the dependability of CPS infrastructures. We address the issues of CPS dependability by using an epidemic model of the underlying dynamics within the CPS’ IoT subsystem (CPS-IoT) and an interference-aware routing reconfiguration. These help to efficiently monitor CPS infrastructure—avoiding routing oscillation, while improving its safety. The contributions of this paper are threefold. Firstly, a CPS orchestration model is proposed that relies upon: (i) Inbound surveillance and outbound actuation to improve dependability and (ii) a novel information diffusion model that uses epidemic states and diffusion sets to produce diffusion patterns across the CPS-IoT. Secondly, the proposed CPS orchestration model is numerically analysed to show its dependability for both sensitive and non-sensitive applications. Finally, a novel interference-aware clustering protocol called “INMP”, which enables network reconfiguration through migration of nodes across clusters, is proposed. It is then bench-marked against prominent IoT protocols to assess its impact on the dependability of the CPS.

22 November 2021 in Sustainability
Verified
Journal Article
Open access
PDF file
OAOlasupo Opeyemi Ajayi
Olasupo Opeyemi Ajayi
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
HMHloniphani Maluleke
Hloniphani Maluleke
IOIsaac Odun-Ayo
Isaac Odun-Ayo
Intelligent Transportation Systems (ITS), also known as Smart Transportation, is an infusion of information and communication technologies into transportation. ITS are a key component of smart cities, which have seen rapid global development in the last few decades. This has in turn translated to an increase in the deployment and adoption of ITS, particularly in countries in the Western world. Unfortunately, this is not the case with the developing countries of Africa and Asia, where dilapidated road infrastructure, poorly maintained public/mass transit vehicles and poverty are major concerns. However, the impact of Westernization and “imported technologies” cannot be overlooked; thus, despite the aforementioned challenges, ITS have found their way into African cities. In this paper, a systematic review was performed to determine the state of the art of ITS in Africa. The output of this systematic review was then fed into a hybrid multi-criteria model to analyse the research landscape, identify connections between published works and reveal research gaps and inequalities in African ITS. African peculiarities inhibiting the widespread implementation of ITS were then discussed, followed by the development of a conceptual architecture for an integrated ITS for African cities.

18 December 2019 in IEEE Access
Verified
Journal Article
Open access
OAOlasupo Opeyemi Ajayi
Olasupo Opeyemi Ajayi
BBBigomokero Antoine Bagula
Bigomokero Antoine Bagula
KMKun Ma
Kun Ma
Inefficient healthcare is a major concern among many African nations. It can be mitigated by building world-class infrastructure connecting different medical facilities for collaboration and resource sharing. Such infrastructure should support the exchange of medical data, enabling access to expertise not available locally. It should be equipped with technologies of the fourth industrial revolution, providing support to doctors thereby enabling African nations leapfrog from poorly equipped to medically prepared. Sadly, world-class healthcare facilities are a missing piece in African public health ecosystems. Medical facilities are either non-existent or prohibitively expensive. Being a collaborative model between Cloud providers, federated Clouds allow the execution of tasks on computing resources flexibly and cost efficiently. This paper aims to interconnect medical facilities across Africa by proposing a Cloud federation for healthcare using co-operative and competitive collaboration models. Simulations were carried out to test the efficiency of these models using two new allocation schemes: Genetic Algorithm-based VM Allocation (GAVA) and Stable Roommate Allocation (SRA). These schemes were bench-marked against First-Fit-Descending (FFD), Best-Fit-Descending (BFD), Binary-Search-Best-Fit (BSBF) allocation schemes; for both light and heavy workloads. Obtained results revealed that the co-operative model resulted in lower delays but higher resource utilization; while the competitive provided faster service delivery and better quality of service. Deployment considerations and potential business models for the African Cloud federation were also presented.