Stephen Joseph - Academia.edu (original) (raw)

Papers by Stephen Joseph

Heliyon

The simplicity, transparency, reliability, high efficiency and robust nature of PID controllers a... more The simplicity, transparency, reliability, high efficiency and robust nature of PID controllers are some of the reasons for their high popularity and acceptance for control in process industries around the world today. Tuning of PID control parameters has been a field of active research and still is. The primary objectives of PID control parameters are to achieve minimal overshoot in steady state response and lesser settling time. With exception of two popular conventional tuning strategies (Ziegler Nichols closed loop oscillation and Cohen-Coon&amp;amp;amp;#39;s process reaction curve) several other methods have been employed for tuning. This work accords a thorough review of state-of-the-art and classical strategies for PID controller parameters tuning using metaheuristic algorithms. Methods appraised are categorized into classical and metaheuristic optimization methods for PID parameters tuning purposes. Details of some metaheuristic algorithms, methods of application, equations and implementation flowcharts/algorithms are presented. Some open problems for future research are also presented. The major goal of this work is to proffer a comprehensive reference source for researchers and scholars working on PID controllers.

Advanced Journal of Social Science, 2021

Background: Although the disparities in mental health outcomes for ethnic minorities in the Unite... more Background: Although the disparities in mental health outcomes for ethnic minorities in the United Kingdom are well-documented, little is known about the role perception of control plays in the experiences of service users and its role in perpetuating or improving health inequalities. This quantitative methods study investigated the perspectives of the members of these communities from the Locus of Control domain. Methods: A small-scale survey (N=50), applied a purposive sampling method to recruit mental health service users of African and Caribbean origin from a South London Borough to complete two structured questionnaires. Data were analysed using SPSS in the examination of the scores, various demographic variables, linear relationships, and other reliability tests. Results: Key findings indicate a moderate to high externality in LOC scores for participants, in general and mental health milieus, with some remarkable differences in ethnicity, gender, and age. Conclusion: The resu...

Illumination of Artificial Intelligence in Cybersecurity and Forensics, 2022

Face recognition which is a sub-discipline of computer vision is gaining a lot of attraction from... more Face recognition which is a sub-discipline of computer vision is gaining a lot of attraction from large audience around the world. Some application areas include forensics, cyber security and intelligent monitoring. Face recognition attendance system serves as a perfect substitute for the conventional attendance system in organizations and classrooms. The challenges associated with most face recognition techniques is inability to detect faces in situations such as noise, pose, facial expression, illumination, obstruction and low performance accuracy. This necessitated the development of more robust and efficient face recognition systems that will overcome the drawbacks associated with conventional techniques. This paper proposed a parallel faces recognition attendance system based on Convolutional Neural Network a branch of artificial intelligence and OpenCV. Experimental results proved the effectiveness of the proposed technique having shown good performance with recognition accuracy of about 98%, precision of 96% and a recall of 0.96. This demonstrates that the proposed method is a promising facial recognition technology.

Scientific Reports, 2020

Biochar may serve as a tool to sustainably mitigate climate change via carbon sequestration and b... more Biochar may serve as a tool to sustainably mitigate climate change via carbon sequestration and by improving soil fertility. Biochar has shown to retain nitrate in its pores, which increases with an organic coating of the inner surfaces and residence time in soil (“aging”). Here we investigated the plant accessibility of the captured nitrate in field-aged biochar, as a pre-requisite for developing carbon-based N fertilization techniques with environmental benefits. Based on previous results, we hypothesized that part of the biochar-captured nitrate would remain unavailable for plants. A two-factorial greenhouse experiment was designed, where the N was applied either as Ca(NO3)2 or as N captured in field-aged biochar at five increasing N doses to quinoa and perennial ryegrass in pots. Interestingly, the biochar-captured N was as plant available as the mineral nitrate, except for the highest dosage. Refuting our hypothesis, no significant amounts of N were extractable at the end of th...

International Journal of Engineering and Management Research, 2019

The ISME journal, May 7, 2017

Biochar and mineral-enriched biochar (MEB) have been used as soil amendments to improve soil fert... more Biochar and mineral-enriched biochar (MEB) have been used as soil amendments to improve soil fertility, sequester carbon and mitigate greenhouse gas emissions. Such beneficial outcomes could be partially mediated by soil bacteria, however little is known about how they directly interact with biochar or MEB. We therefore analyzed the diversity and functions of bacterial communities on the surfaces of one biochar and two different MEBs after a 140-day incubation in soil. The results show that the biochar and the MEBs harbor distinct bacterial communities to the bulk soil. Communities on biochar and MEBs were dominated by a novel Gammaproteobacterium. Genome reconstruction combined with electron microscopy and high-resolution elemental analysis revealed that the bacterium generates energy from the oxidation of iron that is present on the surface. Two other bacteria belonging to the genus Thiobacillus and a novel group within the Oxalbacteraceae were enriched only on the MEBs and they h...

Jurnal Teknologi, 2016

Peer-to-Peer (P2P) applications are bandwidth-heavy and lead to network congestion. The masquerad... more Peer-to-Peer (P2P) applications are bandwidth-heavy and lead to network congestion. The masquerading nature of P2P traffic makes conventional methods of its identification futile. In order to manage and control P2P traffic efficiently preferably in the network, it is necessary to identify such traffic online and accurately. This paper proposes a technique for online P2P identification based on traffic events signatures. The experimental results show that it is able to identify P2P traffic on the fly with an accuracy of 97.7%, precision of 98% and recall of 99.2%.

Environmental science & technology, Jul 10, 2016

Dramatic changes in molecular structure, degradation pathway and porosity of biochar are observed... more Dramatic changes in molecular structure, degradation pathway and porosity of biochar are observed at pyrolysis temperatures ranging from 250-550 °C, when bamboo biomass is pretreated by iron-sulfate-clay slurries (iron-clay biochar), as compared to untreated bamboo biochar. Electron microscopy analysis of the biochar reveals the infusion of mineral species into the pores of the biochar and formation of mineral nano-structures. Quantitative 13C Nuclear Magnetic Resonance (NMR) spectroscopy shows that the presence of the iron-clay prevents degradation of the cellulosic fraction at pyrolysis temperatures of 250 °C, whereas at higher temperatures (350-550 °C), the clay promotes biomass degradation, resulting in an increase in both the concentrations of condensed aromatic, acidic and phenolic carbon species. The porosity of the biochar, as measured by NMR cryo-porosimetry, is altered by the iron-clay pretreatment. In presence of the clay, at lower pyrolysis temperatures, the biochar deve...

Frontiers in microbiology, 2016

Organic farming avoids the use of synthetic fertilizers and promises food production with minimal... more Organic farming avoids the use of synthetic fertilizers and promises food production with minimal environmental impact, however this farming practice does not often result in the same productivity as conventional farming. In recent years, biochar has received increasing attention as an agricultural amendment and by coating it with minerals to form biochar-mineral complex (BMC) carbon retention and nutrient availability can be improved. However, little is known about the potential of BMC in improving organic farming. We therefore investigated here how soil, bacterial and plant properties respond to a combined treatment of BMC and an organic fertilizer, i.e., a compost based on poultry manure. In a pakchoi pot trial, BMC and compost showed synergistic effects on soil properties, and specifically by increasing nitrate content. Soil nitrate has been previously observed to increase leaf size and we correspondingly saw an increase in the surface area of pakchoi leaves under the combined t...

Scientific reports, Jan 30, 2015

Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contr... more Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contributing to global warming and depletion of stratospheric ozone. Biochar addition has shown potential to lower soil N2O emission, with the mechanisms remaining unclear. We incubated eucalypt biochar (550 °C) - 0, 1 and 5% (w/w) in Ferralsol at 3 water regimes (12, 39 and 54% WFPS) - in a soil column, following gamma irradiation. After N2O was injected at the base of the soil column, in the 0% biochar control 100% of expected injected N2O was released into headspace, declining to 67% in the 5% amendment. In a 100% biochar column at 6% WFPS, only 16% of the expected N2O was observed. X-ray photoelectron spectroscopy identified changes in surface functional groups suggesting interactions between N2O and the biochar surfaces. We have shown increases in -O-C = N /pyridine pyrrole/NH3, suggesting reactions between N2O and the carbon (C) matrix upon exposure to N2O. With increasing rates of bioc...

2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2015

Fertile dark soils made by humans in the Amazon basin, terra preta, have influenced the manufactu... more Fertile dark soils made by humans in the Amazon basin, terra preta, have influenced the manufacture of the biochar based fertilizers. Different types of biochar exist but not all of them are good in improving the quality of the soil. FTIR was used to distinguish between the more and the less fertile biochar.

Jurnal Teknologi, 2015

Malware is a computer security problem that can morph to evade traditional detection methods base... more Malware is a computer security problem that can morph to evade traditional detection methods based on known signature matching. Since new malware variants contain patterns that are similar to those in observed malware, machine learning techniques can be used to identify new malware. This work presents a comparative study of several feature selection methods with four different machine learning classifiers in the context of static malware detection based on n-grams analysis. The result shows that the use of Principal Component Analysis (PCA) feature selection and Support Vector Machines (SVM) classification gives the best classification accuracy using a minimum number of features.

PloS one, 2015

The study of the interaction of bacteria with surfaces requires the detection of specific bacteri... more The study of the interaction of bacteria with surfaces requires the detection of specific bacterial groups with high spatial resolution. Here, we describe a method to rapidly and efficiently add nanogold particles to oligonucleotide probes, which target bacterial ribosomal RNA. These nanogold-labeled probes are then used in an in situ hybridization procedure that ensures both cellular integrity and high specificity. Electron microscopy subsequently enables the visualization of specific cells with high local precision on complex surface structures. This method will contribute to an increased understanding of how bacteria interact with surface structures on a sub-micron scale.

Women's Studies International Forum, 2004

Pesquisa Agropecuária Brasileira, 2012

The objective of this work was to determine the contribution of dissolved organic carbon (DOC) fr... more The objective of this work was to determine the contribution of dissolved organic carbon (DOC) from a biochar mineral complex (BMC), so as to better understand the interactions between DOC, biochar, clay, and minerals during thermal treatment, and the effects of BMC on amended soils. The BMC was prepared by heating a mixture of a H3PO4-treated saligna biochar from Acacia saligna, clays, other minerals, and chicken manure. The BMC was applied to a sandy loam soil in Western Australia, where wheat was grown. Liquid chromatography-organic carbon detection (LC-OCD) tests were carried out on water extracts from the untreated biochar, the BMC, the BMC-amended soil, and on a control soil to measure the DOC concentration. LC-OCD tests provide a fingerprint of the DOC, which allows the fractions of DOC to be determined. Thermal processing enhanced the reaction of the A. saligna biochar with manure, clays and minerals, and affected the distribution of the DOC fractions. Notably, the process l...

Nature Communications, 2010