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My research explores the integration of data-based (e.g. machine learning) and knowledge-based (e.g. ontologies) AI in an agent architecture for health monitoring using sensors. I'm supervised by A/Prof. Deshen Moodley. Prior to this, I graduated with Distinction from the University of Manchester, where I earned an MSc in Advanced Computer Science with a specialization in AI.
Latest Research Publications:
1.
Wanyana T, Nzomo M, Price CS, Moodley D. Combining Machine Learning and Bayesian Networks for ECG Interpretation and Explanation. In: Proceedings of the 8th International Conference on Information and Communication Technologies for Ageing Well and e-Health - ICT4AWE. INSTICC: SciTePress; 2022. doi:https://doi.org/10.5220/0011046100003188.
We explore how machine learning (ML) and Bayesian networks (BNs) can be combined in a personal health agent (PHA) for the detection and interpretation of electrocardiogram (ECG) characteristics. We propose a PHA that uses ECG data from wearables to monitor heart activity, and interprets and explains the observed readings. We focus on atrial fibrillation (AF), the commonest type of arrhythmia. The absence of a P-wave in an ECG is the hallmark indication of AF. Four ML models are trained to classify an ECG signal based on the presence or absence of the P-wave: multilayer perceptron (MLP), logistic regression, support vector machine, and random forest. The MLP is the best performing model with an accuracy of 89.61% and an F1 score of 88.68%. A BN representing AF risk factors is developed based on expert knowledge from the literature and evaluated using Pitchforth and Mengersen’s validation framework. The P-wave presence or absence as determined by the ML model is input into the BN. The PHA is evaluated using sample use cases to illustrate how the BN can explain the occurrence of AF using diagnostic reasoning. This gives the most likely AF risk factors for the individual
@inbook{478,
author = {Tezira Wanyana, Mbithe Nzomo, C. Sue Price, Deshen Moodley},
title = {Combining Machine Learning and Bayesian Networks for ECG Interpretation and Explanation},
abstract = {We explore how machine learning (ML) and Bayesian networks (BNs) can be combined in a personal health agent (PHA) for the detection and interpretation of electrocardiogram (ECG) characteristics. We propose a PHA that uses ECG data from wearables to monitor heart activity, and interprets and explains the observed readings. We focus on atrial fibrillation (AF), the commonest type of arrhythmia. The absence of a P-wave in an ECG is the hallmark indication of AF. Four ML models are trained to classify an ECG signal based on the presence or absence of the P-wave: multilayer perceptron (MLP), logistic regression, support vector machine, and random forest. The MLP is the best performing model with an accuracy of 89.61% and an F1 score of 88.68%. A BN representing AF risk factors is developed based on expert knowledge from the literature and evaluated using Pitchforth and Mengersen’s validation framework. The P-wave presence or absence as determined by the ML model is input into the BN. The PHA is evaluated using sample use cases to illustrate how the BN can explain the occurrence of AF using diagnostic reasoning. This gives the most likely AF risk factors for the individual},
year = {2022},
journal = {Proceedings of the 8th International Conference on Information and Communication Technologies for Ageing Well and e-Health - ICT4AWE},
pages = {81-92},
publisher = {SciTePress},
address = {INSTICC},
isbn = {978-989-758-566-1},
doi = {https://doi.org/10.5220/0011046100003188},
}
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Latest Research Publications:
1.
Casini G, Meyer T, Paterson-Jones G. KLM-Style Defeasibility for Restricted First-Order Logic. In: 19th International Workshop on Non-Monotonic Reasoning. Online; 2021. https://drive.google.com/open?id=1WSIl3TOrXBhaWhckWN4NLXoD9AVFKp5R.
We extend the KLM approach to defeasible reasoning to be applicable to a restricted version of first-order logic. We describe defeasibility for this logic using a set of rationality postulates, provide an appropriate semantics for it, and present a representation result that characterises the semantic description of defeasibility in terms of the rationality postulates. Based on this theoretical core, we then propose a version of defeasible entailment that is inspired by Rational Closure as it is defined for defeasible propositional logic and defeasible description logics. We show that this form of defeasible entailment is rational in the sense that it adheres to our rationality postulates. The work in this paper is the first step towards our ultimate goal of introducing KLM-style defeasible reasoning into the family of Datalog+/- ontology languages.
@{429,
author = {Giovanni Casini, Tommie Meyer, Guy Paterson-Jones},
title = {KLM-Style Defeasibility for Restricted First-Order Logic},
abstract = {We extend the KLM approach to defeasible reasoning to be applicable to a restricted version of first-order logic. We describe defeasibility for this logic using a set of rationality postulates, provide an appropriate semantics for it, and present a representation result that characterises the semantic description of defeasibility in terms of the rationality postulates. Based on this theoretical core, we then propose a version of defeasible entailment that is inspired by Rational Closure as it is defined for defeasible propositional logic and defeasible description logics. We show that this form of defeasible entailment is rational in the sense that it adheres to our rationality postulates. The work in this paper is the first step towards our ultimate goal of introducing KLM-style defeasible reasoning into the family of Datalog+/- ontology languages.},
year = {2021},
journal = {19th International Workshop on Non-Monotonic Reasoning},
pages = {184-193},
month = {03/11/2021-05/11/2021},
address = {Online},
url = {https://drive.google.com/open?id=1WSIl3TOrXBhaWhckWN4NLXoD9AVFKp5R},
}
1.
Paterson-Jones G, Meyer T. A Boolean Extension of KLM-style Conditional Reasoning. In: First Southern African Conference for AI Research (SACAIR 2020). Muldersdrift, South Africa: Springer; 2020. doi:10.1007/978-3-030-66151-9_15.
Propositional KLM-style defeasible reasoning involves extending propositional logic with a new logical connective that can express defeasible (or conditional) implications, with semantics given by ordered structures known as ranked interpretations. KLM-style defeasible entailment is referred to as rational whenever the defeasible entailment relation under consideration generates a set of defeasible implications all satisfying a set of rationality postulates known as the KLM postulates. In a recent paper Booth et al. proposed PTL, a logic that is more expressive than the core KLM logic. They proved an impossibility result, showing that defeasible entailment for PTL fails to satisfy a set of rationality postulates similar in spirit to the KLM postulates. Their interpretation of the impossibility result is that defeasible entailment for PTL need not be unique. In this paper we continue the line of research in which the expressivity of the core KLM logic is extended. We present the logic Boolean KLM (BKLM) in which we allow for disjunctions, conjunctions, and negations, but not nesting, of defeasible implications. Our contribution is twofold. Firstly, we show (perhaps surprisingly) that BKLM is more expressive than PTL. Our proof is based on the fact that BKLM can characterise all single ranked interpretations, whereas PTL cannot. Secondly, given that the PTL impossibility result also applies to BKLM, we adapt the different forms of PTL entailment proposed by Booth et al. to apply to BKLM.
@{413,
author = {Guy Paterson-Jones, Tommie Meyer},
title = {A Boolean Extension of KLM-style Conditional Reasoning},
abstract = {Propositional KLM-style defeasible reasoning involves extending propositional logic with a new logical connective that can express defeasible (or conditional) implications, with semantics given by ordered structures known as ranked interpretations. KLM-style defeasible entailment is referred to as rational whenever the defeasible entailment relation under consideration generates a set of defeasible implications all satisfying a set of rationality postulates known as the KLM postulates. In a recent paper Booth et al. proposed PTL, a logic that is more expressive than the core KLM logic. They proved an impossibility result, showing that defeasible entailment for PTL fails to satisfy a set of rationality postulates similar in spirit to the KLM postulates. Their interpretation of the impossibility result is that defeasible entailment for PTL need not be unique. In this paper we continue the line of research in which the expressivity of the core KLM logic is extended. We present the logic Boolean KLM (BKLM) in which we allow for disjunctions, conjunctions, and negations, but not nesting, of defeasible implications. Our contribution is twofold. Firstly, we show (perhaps surprisingly) that BKLM is more expressive than PTL. Our proof is based on the fact that BKLM can characterise all single ranked interpretations, whereas PTL cannot. Secondly, given that the PTL impossibility result also applies to BKLM, we adapt the different forms of PTL entailment proposed by Booth et al. to apply to BKLM.},
year = {2020},
journal = {First Southern African Conference for AI Research (SACAIR 2020)},
pages = {236-252},
month = {22/02/2021-26/02/2021},
publisher = {Springer},
address = {Muldersdrift, South Africa},
isbn = {978-3-030-66151-9},
url = {https://link.springer.com/book/10.1007/978-3-030-66151-9},
doi = {10.1007/978-3-030-66151-9_15},
}
1.
Paterson-Jones G, Casini G, Meyer T. BKLM - An expressive logic for defeasible reasoning. 18th International Workshop on Non-Monotonic Reasoning. 2020.
Propositional KLM-style defeasible reasoning involves a core propositional logic capable of expressing defeasible (or conditional) implications. The semantics for this logic is based on Kripke-like structures known as ranked interpretations. KLM-style defeasible entailment is referred to as rational whenever the defeasible entailment relation under consideration generates a set of defeasible implications all satisfying a set of rationality postulates known as the KLM postulates. In a recent paper Booth et al. proposed PTL, a logic that is more expressive than the core KLM logic. They proved an impossibility result, showing that defeasible entailment for PTL fails to satisfy a set of rationality postulates similar in spirit to the KLM postulates. Their interpretation of the impossibility result is that defeasible entailment for PTL need not be unique.
In this paper we continue the line of research in which the expressivity of the core KLM logic is extended. We present the logic Boolean KLM (BKLM) in which we allow for disjunctions, conjunctions, and negations, but not nesting, of defeasible implications. Our contribution is twofold. Firstly, we show (perhaps surprisingly) that BKLM is more expressive than PTL. Our proof is based on the fact that BKLM can characterise all single ranked interpretations, whereas PTL cannot. Secondly, given that the PTL impossibility result also applies to BKLM, we adapt the different forms of PTL entailment proposed by Booth et al. to apply to BKLM.
@misc{383,
author = {Guy Paterson-Jones, Giovanni Casini, Tommie Meyer},
title = {BKLM - An expressive logic for defeasible reasoning},
abstract = {Propositional KLM-style defeasible reasoning involves a core propositional logic capable of expressing defeasible (or conditional) implications. The semantics for this logic is based on Kripke-like structures known as ranked interpretations. KLM-style defeasible entailment is referred to as rational whenever the defeasible entailment relation under consideration generates a set of defeasible implications all satisfying a set of rationality postulates known as the KLM postulates. In a recent paper Booth et al. proposed PTL, a logic that is more expressive than the core KLM logic. They proved an impossibility result, showing that defeasible entailment for PTL fails to satisfy a set of rationality postulates similar in spirit to the KLM postulates. Their interpretation of the impossibility result is that defeasible entailment for PTL need not be unique.
In this paper we continue the line of research in which the expressivity of the core KLM logic is extended. We present the logic Boolean KLM (BKLM) in which we allow for disjunctions, conjunctions, and negations, but not nesting, of defeasible implications. Our contribution is twofold. Firstly, we show (perhaps surprisingly) that BKLM is more expressive than PTL. Our proof is based on the fact that BKLM can characterise all single ranked interpretations, whereas PTL cannot. Secondly, given that the PTL impossibility result also applies to BKLM, we adapt the different forms of PTL entailment proposed by Booth et al. to apply to BKLM.},
year = {2020},
journal = {18th International Workshop on Non-Monotonic Reasoning},
month = {12/09/2020-24/09/2020},
}
Research Groups:
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Latest Research Publications:
1.
Price CS, Moodley D, Pillay A, Rens G. An adaptive probabilistic agent architecture for modelling sugarcane growers’ decision-making. South African Computer Journal. 2022;34(1). doi:https://doi.org/10.18489/sacj.v34i1.857.
Building computational models of agents in dynamic, partially observable and stochastic environments is challenging. We propose a cognitive computational model of sugarcane growers’ daily decision-making to examine sugarcane supply chain complexities. Growers make decisions based on uncertain weather forecasts; cane dryness; unforeseen emergencies; and the mill’s unexpected call for delivery of a different amount of cane. The Belief-Desire-Intention (BDI) architecture has been used to model cognitive agents in many domains, including agriculture. However, typical implementations of this architecture have represented beliefs symbolically, so uncertain beliefs are usually not catered for. Here we show that a BDI architecture, enhanced with a dynamic decision network (DDN), suitably models sugarcane grower agents’ repeated daily decisions. Using two complex scenarios, we demonstrate that the agent selects the appropriate intention, and suggests how the grower should act adaptively and proactively to achieve his goals. In addition, we provide a mapping for using a DDN in a BDI architecture. This architecture can be used for modelling sugarcane grower agents in an agent-based simulation. The mapping of the DDN’s use in the BDI architecture enables this work to be applied to other domains for modelling agents’ repeated decisions in partially observable, stochastic and dynamic environments.
@article{488,
author = {C. Sue Price, Deshen Moodley, Anban Pillay, Gavin Rens},
title = {An adaptive probabilistic agent architecture for modelling sugarcane growers’ decision-making},
abstract = {Building computational models of agents in dynamic, partially observable and stochastic environments is challenging. We propose a cognitive computational model of sugarcane growers’ daily decision-making to examine sugarcane supply chain complexities. Growers make decisions based on uncertain weather forecasts; cane dryness; unforeseen emergencies; and the mill’s unexpected call for delivery of a different amount of cane. The Belief-Desire-Intention (BDI) architecture has been used to model cognitive agents in many domains, including agriculture. However, typical implementations of this architecture have represented beliefs symbolically, so uncertain beliefs are usually not catered for. Here we show that a BDI architecture, enhanced with a dynamic decision network (DDN), suitably models sugarcane grower agents’ repeated daily decisions. Using two complex scenarios, we demonstrate that the agent selects the appropriate intention, and suggests how the grower should act adaptively and proactively to achieve his goals. In addition, we provide a mapping for using a DDN in a BDI architecture. This architecture can be used for modelling sugarcane grower agents in an agent-based simulation. The mapping of the DDN’s use in the BDI architecture enables this work to be applied to other domains for modelling agents’ repeated decisions in partially observable, stochastic and dynamic environments.},
year = {2022},
journal = {South African Computer Journal},
volume = {34},
pages = {152-191},
issue = {1},
url = {https://sacj.cs.uct.ac.za/index.php/sacj/article/view/857},
doi = {https://doi.org/10.18489/sacj.v34i1.857},
}
1.
Clark A, Pillay A, Moodley D. A system for pose analysis and selection in virtual reality environments. In: SAICSIT ’20: Conference of the South African Institute of Computer Scientists and Information Technologists 2020. Virtual: ACM Digital Library; 2020. https://dl.acm.org/doi/proceedings/10.1145/3410886.
Depth cameras provide a natural and intuitive user interaction mechanism in virtual reality environments by using hand gestures as the primary user input. However, building robust VR systems that use depth cameras are challenging. Gesture recognition accuracy is affected by occlusion, variation in hand orientation and misclassification of similar hand gestures. This research explores the limits of the Leap Motion depth camera for static hand pose recognition in virtual reality applications. We propose a system for analysing static hand poses and for systematically identifying a pose set that can achieve a near-perfect recognition accuracy. The system consists of a hand pose taxonomy, a pose notation, a machine learning classifier and an algorithm to identify a reliable pose set that can achieve near perfect accuracy levels. We used this system to construct a benchmark hand pose data set containing 2550 static hand pose instances, and show how the algorithm can be used to systematically derive a set of poses that can produce an accuracy of 99% using a Support Vector Machine classifier.
@{379,
author = {Andrew Clark, Anban Pillay, Deshen Moodley},
title = {A system for pose analysis and selection in virtual reality environments},
abstract = {Depth cameras provide a natural and intuitive user interaction mechanism in virtual reality environments by using hand gestures as the primary user input. However, building robust VR systems that use depth cameras are challenging. Gesture recognition accuracy is affected by occlusion, variation in hand orientation and misclassification of similar hand gestures. This research explores the limits of the Leap Motion depth camera for static hand pose recognition in virtual reality applications. We propose a system for analysing static hand poses and for systematically identifying a pose set that can achieve a near-perfect recognition accuracy. The system consists of a hand pose taxonomy, a pose notation, a machine learning classifier and an algorithm to identify a reliable pose set that can achieve near perfect accuracy levels. We used this system to construct a benchmark hand pose data set containing 2550 static hand pose instances, and show how the algorithm can be used to systematically derive a set of poses that can produce an accuracy of 99% using a Support Vector Machine classifier.},
year = {2020},
journal = {SAICSIT '20: Conference of the South African Institute of Computer Scientists and Information Technologists 2020},
pages = {210-216},
month = {14/09/2020},
publisher = {ACM Digital Library},
address = {Virtual},
isbn = {978-1-4503-8847-4},
url = {https://dl.acm.org/doi/proceedings/10.1145/3410886},
}
1.
Price CS, Moodley D, Pillay A. Modelling uncertain adaptive decisions: Application to KwaZulu-Natal sugarcane growers. In: Forum for Artificial Intelligence Research (FAIR2019). Cape Town: CEUR; 2019. http://ceur-ws.org/Vol-2540/FAIR2019_paper_53.pdf.
A dynamic Bayesian decision network was developed to model the preharvest burning decision-making processes of sugarcane growers in a KwaZulu-Natal sugarcane supply chain and extends previous work by Price et al. (2018). This model was created using an iterative development approach. This paper recounts the development and validation process of the third version of the model. The model was validated using Pitchforth and Mengersen (2013)’s framework for validating expert elicited Bayesian networks. During this process, growers and cane supply members assessed the model in a focus group by executing the model, and reviewing the results of a prerun scenario. The participants were generally positive about how the model represented their decision-making processes. However, they identified some issues that could be addressed in the next iteration. Dynamic Bayesian decision networks offer a promising approach to modelling adaptive decisions in uncertain conditions. This model can be used to simulate the cognitive mechanism for a grower agent in a simulation of a sugarcane supply chain.
@{244,
author = {C. Sue Price, Deshen Moodley, Anban Pillay},
title = {Modelling uncertain adaptive decisions: Application to KwaZulu-Natal sugarcane growers},
abstract = {A dynamic Bayesian decision network was developed to model the preharvest burning decision-making processes of sugarcane growers in a KwaZulu-Natal sugarcane supply chain and extends previous work by Price et al. (2018). This model was created using an iterative development approach. This paper recounts the development and validation process of the third version of the model. The model was validated using Pitchforth and Mengersen (2013)’s framework for validating expert elicited Bayesian networks. During this process, growers and cane supply members assessed the model in a focus group by executing the model, and reviewing the results of a prerun scenario. The participants were generally positive about how the model represented their decision-making processes. However, they identified some issues that could be addressed in the next iteration. Dynamic Bayesian decision networks offer a promising approach to modelling adaptive decisions in uncertain conditions. This model can be used to simulate the cognitive mechanism for a grower agent in a simulation of a sugarcane supply chain.},
year = {2019},
journal = {Forum for Artificial Intelligence Research (FAIR2019)},
pages = {145-160},
month = {4/12-6/12},
publisher = {CEUR},
address = {Cape Town},
url = {http://ceur-ws.org/Vol-2540/FAIR2019_paper_53.pdf},
}
1.
Moodley D, Pillay A, Seebregts C. Establishing a Health Informatics Research Laboratory in South Africa . In: Digital Re-imagination Colloquium 2018. NEMISA; 2018. http://uir.unisa.ac.za/bitstream/handle/10500/25615/Digital%20Skills%20Proceedings%202018.pdf?sequence=1&isAllowed=y.
Aim/Purpose
The aim of this project was to explore models for stimulating health
informatics innovation and capacity development in South Africa.
Background
There is generally a critical lack of health informatics innovation and capacity in South Africa and sub-Saharan Africa. This is despite the wide anticipation that digital health systems will play a fundamental role in strengthening health systems and improving service delivery
Methodology
We established a program over four years to train Masters and Doctoral students and conducted research projects across a wide range of biomedical and health informatics technologies at a leading South African university. We also developed a Health Architecture Laboratory Innovation and Development Ecosystem (HeAL-IDE) designed to be a long-lasting and potentially reproducible output of the project.
Contribution
We were able to demonstrate a successful model for building innovation and capacity in a sustainable way. Key outputs included: (i)a successful partnership model; (ii) a sustainable HeAL-IDE; (iii) research papers; (iv) a world-class software product and several
demonstrators; and (iv) highly trained staff.
Findings
Our main findings are that: (i) it is possible to create a local ecosystem for innovation and capacity building that creates value for the partners (a university and a private non-profit company); (ii) the ecosystem is able to create valuable outputs that would be much less likely to have been developed singly by each partner, and; (iii) the ecosystem could serve as a powerful model for adoption in other settings.
Recommendations for Practitioners
Non-profit companies and non-governmental organizations implementing health information systems in South Africa and other low resource settings have an opportunity to partner with local universities for purposes of internal capacity development and assisting with the research, reflection and innovation aspects of their projects and programmes.
Recommendation for Researchers
Applied health informatics researchers working in low resource settings could productively partner with local implementing organizations in order to gain a better understanding of the challenges and requirements at field sites and to accelerate the testing and deployment of health information technology solutions.
Impact on Society
This research demonstrates a model that can deliver valuable software products for public health.
Future Research
It would be useful to implement the model in other settings and research whether the model is more generally useful
@{252,
author = {Deshen Moodley, Anban Pillay, Chris Seebregts},
title = {Establishing a Health Informatics Research Laboratory in South Africa},
abstract = {Aim/Purpose
The aim of this project was to explore models for stimulating health
informatics innovation and capacity development in South Africa.
Background
There is generally a critical lack of health informatics innovation and capacity in South Africa and sub-Saharan Africa. This is despite the wide anticipation that digital health systems will play a fundamental role in strengthening health systems and improving service delivery
Methodology
We established a program over four years to train Masters and Doctoral students and conducted research projects across a wide range of biomedical and health informatics technologies at a leading South African university. We also developed a Health Architecture Laboratory Innovation and Development Ecosystem (HeAL-IDE) designed to be a long-lasting and potentially reproducible output of the project.
Contribution
We were able to demonstrate a successful model for building innovation and capacity in a sustainable way. Key outputs included: (i)a successful partnership model; (ii) a sustainable HeAL-IDE; (iii) research papers; (iv) a world-class software product and several
demonstrators; and (iv) highly trained staff.
Findings
Our main findings are that: (i) it is possible to create a local ecosystem for innovation and capacity building that creates value for the partners (a university and a private non-profit company); (ii) the ecosystem is able to create valuable outputs that would be much less likely to have been developed singly by each partner, and; (iii) the ecosystem could serve as a powerful model for adoption in other settings.
Recommendations for Practitioners
Non-profit companies and non-governmental organizations implementing health information systems in South Africa and other low resource settings have an opportunity to partner with local universities for purposes of internal capacity development and assisting with the research, reflection and innovation aspects of their projects and programmes.
Recommendation for Researchers
Applied health informatics researchers working in low resource settings could productively partner with local implementing organizations in order to gain a better understanding of the challenges and requirements at field sites and to accelerate the testing and deployment of health information technology solutions.
Impact on Society
This research demonstrates a model that can deliver valuable software products for public health.
Future Research
It would be useful to implement the model in other settings and research whether the model is more generally useful},
year = {2018},
journal = {Digital Re-imagination Colloquium 2018},
pages = {16 - 24},
month = {13/03 - 15/03},
publisher = {NEMISA},
isbn = {978-0-6399275-0-3},
url = {http://uir.unisa.ac.za/bitstream/handle/10500/25615/Digital%20Skills%20Proceedings%202018.pdf?sequence=1&isAllowed=y},
}
1.
Ndaba M, Pillay A, Ezugwu A. An Improved Generalized Regression Neural Network for Type II Diabetes Classification. In: Iccsa 2018, lncs 10963. 10963rd ed. Springer International Publishing AG; 2018.
This paper proposes an improved Generalized Regression Neural Network (KGRNN) for the diagnosis of type II diabetes. Dia- betes, a widespread chronic disease, is a metabolic disorder that develops when the body does not make enough insulin or is unable to use insulin effectively. Type II diabetes is the most common type and accounts for an estimated 90% of cases. The novel KGRNN technique reported in this study uses an enhanced K-Means clustering technique (CVE-K-Means) to produce cluster centers (centroids) that are used to train the network. The technique was applied to the Pima Indian diabetes dataset, a widely used benchmark dataset for Diabetes diagnosis. The technique outper- forms the best known GRNN techniques for Type II diabetes diagnosis in terms of classification accuracy and computational time and obtained a classification accuracy of 86% with 83% sensitivity and 87% specificity. The Area Under the Receiver Operating Characteristic Curve (ROC) of 87% was obtained.
@inbook{195,
author = {Moeketsi Ndaba, Anban Pillay, Absalom Ezugwu},
title = {An Improved Generalized Regression Neural Network for Type II Diabetes Classification},
abstract = {This paper proposes an improved Generalized Regression Neural Network (KGRNN) for the diagnosis of type II diabetes. Dia- betes, a widespread chronic disease, is a metabolic disorder that develops when the body does not make enough insulin or is unable to use insulin effectively. Type II diabetes is the most common type and accounts for an estimated 90% of cases. The novel KGRNN technique reported in this study uses an enhanced K-Means clustering technique (CVE-K-Means) to produce cluster centers (centroids) that are used to train the network. The technique was applied to the Pima Indian diabetes dataset, a widely used benchmark dataset for Diabetes diagnosis. The technique outper- forms the best known GRNN techniques for Type II diabetes diagnosis in terms of classification accuracy and computational time and obtained a classification accuracy of 86% with 83% sensitivity and 87% specificity. The Area Under the Receiver Operating Characteristic Curve (ROC) of 87% was obtained.},
year = {2018},
journal = {ICCSA 2018, LNCS 10963},
edition = {10963},
pages = {659-671},
publisher = {Springer International Publishing AG},
isbn = {3319951718},
}
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Sue Price is a Lecturer in Information Systems at the University of KwaZulu-Natal (Westville campus). She is also studying towards a PhD in Computer Science at UKZN, where she is using agent-based modelling and simulation to model the complexities of a sugarcane supply chain.
Latest Research Publications:
1.
Price CS, Moodley D, Pillay A, Rens G. An adaptive probabilistic agent architecture for modelling sugarcane growers’ decision-making. South African Computer Journal. 2022;34(1). doi:https://doi.org/10.18489/sacj.v34i1.857.
Building computational models of agents in dynamic, partially observable and stochastic environments is challenging. We propose a cognitive computational model of sugarcane growers’ daily decision-making to examine sugarcane supply chain complexities. Growers make decisions based on uncertain weather forecasts; cane dryness; unforeseen emergencies; and the mill’s unexpected call for delivery of a different amount of cane. The Belief-Desire-Intention (BDI) architecture has been used to model cognitive agents in many domains, including agriculture. However, typical implementations of this architecture have represented beliefs symbolically, so uncertain beliefs are usually not catered for. Here we show that a BDI architecture, enhanced with a dynamic decision network (DDN), suitably models sugarcane grower agents’ repeated daily decisions. Using two complex scenarios, we demonstrate that the agent selects the appropriate intention, and suggests how the grower should act adaptively and proactively to achieve his goals. In addition, we provide a mapping for using a DDN in a BDI architecture. This architecture can be used for modelling sugarcane grower agents in an agent-based simulation. The mapping of the DDN’s use in the BDI architecture enables this work to be applied to other domains for modelling agents’ repeated decisions in partially observable, stochastic and dynamic environments.
@article{488,
author = {C. Sue Price, Deshen Moodley, Anban Pillay, Gavin Rens},
title = {An adaptive probabilistic agent architecture for modelling sugarcane growers’ decision-making},
abstract = {Building computational models of agents in dynamic, partially observable and stochastic environments is challenging. We propose a cognitive computational model of sugarcane growers’ daily decision-making to examine sugarcane supply chain complexities. Growers make decisions based on uncertain weather forecasts; cane dryness; unforeseen emergencies; and the mill’s unexpected call for delivery of a different amount of cane. The Belief-Desire-Intention (BDI) architecture has been used to model cognitive agents in many domains, including agriculture. However, typical implementations of this architecture have represented beliefs symbolically, so uncertain beliefs are usually not catered for. Here we show that a BDI architecture, enhanced with a dynamic decision network (DDN), suitably models sugarcane grower agents’ repeated daily decisions. Using two complex scenarios, we demonstrate that the agent selects the appropriate intention, and suggests how the grower should act adaptively and proactively to achieve his goals. In addition, we provide a mapping for using a DDN in a BDI architecture. This architecture can be used for modelling sugarcane grower agents in an agent-based simulation. The mapping of the DDN’s use in the BDI architecture enables this work to be applied to other domains for modelling agents’ repeated decisions in partially observable, stochastic and dynamic environments.},
year = {2022},
journal = {South African Computer Journal},
volume = {34},
pages = {152-191},
issue = {1},
url = {https://sacj.cs.uct.ac.za/index.php/sacj/article/view/857},
doi = {https://doi.org/10.18489/sacj.v34i1.857},
}
1.
Wanyana T, Nzomo M, Price CS, Moodley D. Combining Machine Learning and Bayesian Networks for ECG Interpretation and Explanation. In: Proceedings of the 8th International Conference on Information and Communication Technologies for Ageing Well and e-Health - ICT4AWE. INSTICC: SciTePress; 2022. doi:https://doi.org/10.5220/0011046100003188.
We explore how machine learning (ML) and Bayesian networks (BNs) can be combined in a personal health agent (PHA) for the detection and interpretation of electrocardiogram (ECG) characteristics. We propose a PHA that uses ECG data from wearables to monitor heart activity, and interprets and explains the observed readings. We focus on atrial fibrillation (AF), the commonest type of arrhythmia. The absence of a P-wave in an ECG is the hallmark indication of AF. Four ML models are trained to classify an ECG signal based on the presence or absence of the P-wave: multilayer perceptron (MLP), logistic regression, support vector machine, and random forest. The MLP is the best performing model with an accuracy of 89.61% and an F1 score of 88.68%. A BN representing AF risk factors is developed based on expert knowledge from the literature and evaluated using Pitchforth and Mengersen’s validation framework. The P-wave presence or absence as determined by the ML model is input into the BN. The PHA is evaluated using sample use cases to illustrate how the BN can explain the occurrence of AF using diagnostic reasoning. This gives the most likely AF risk factors for the individual
@inbook{478,
author = {Tezira Wanyana, Mbithe Nzomo, C. Sue Price, Deshen Moodley},
title = {Combining Machine Learning and Bayesian Networks for ECG Interpretation and Explanation},
abstract = {We explore how machine learning (ML) and Bayesian networks (BNs) can be combined in a personal health agent (PHA) for the detection and interpretation of electrocardiogram (ECG) characteristics. We propose a PHA that uses ECG data from wearables to monitor heart activity, and interprets and explains the observed readings. We focus on atrial fibrillation (AF), the commonest type of arrhythmia. The absence of a P-wave in an ECG is the hallmark indication of AF. Four ML models are trained to classify an ECG signal based on the presence or absence of the P-wave: multilayer perceptron (MLP), logistic regression, support vector machine, and random forest. The MLP is the best performing model with an accuracy of 89.61% and an F1 score of 88.68%. A BN representing AF risk factors is developed based on expert knowledge from the literature and evaluated using Pitchforth and Mengersen’s validation framework. The P-wave presence or absence as determined by the ML model is input into the BN. The PHA is evaluated using sample use cases to illustrate how the BN can explain the occurrence of AF using diagnostic reasoning. This gives the most likely AF risk factors for the individual},
year = {2022},
journal = {Proceedings of the 8th International Conference on Information and Communication Technologies for Ageing Well and e-Health - ICT4AWE},
pages = {81-92},
publisher = {SciTePress},
address = {INSTICC},
isbn = {978-989-758-566-1},
doi = {https://doi.org/10.5220/0011046100003188},
}
1.
Mbonye V, Price CS. Students’ use of on-campus wireless networks: Analysis by residence type. In: 2021 International Conference on Artificial Intelligence, Big Data, Computing and Data Communication Systems (icABCD). Durban, South Africa: IEEE; 2021. doi:https://doi.org/10.1109/icABCD51485.2021.9519327.
Universities supply free Wi-Fi to registered students on campus to access learning materials. Many issues could reduce the quality of students' Wi-Fi use, e.g., devices using different Wi-Fi standards than those used on campus, and numerous students accessing Wi-Fi through a single access point simultaneously. Understanding where, when and how students use Wi-Fi on campus can help IT administrators to provide an adequate Wi-Fi service. This pre-COVID study adopted a mixed method approach. Questionnaires were completed by a representative sample of 373 students on the Westville campus of the University of KwaZulu-Natal, South Africa. Two Information Communication Services (lCS) staff members were interviewed to gain insights into how the Wi-Fi was set up, and their perspectives on how students utilise the Wi-Fi. The questionnaire data were analysed statistically, and interview results were used to explain results. The students' most used venues, and the places they encountered poor and best Wi-Fi signal quality, are presented, along with the durations of use and problems encountered. When analysing these results by students' residence type, each category showed a different pattern of use. These results can help IT administrators understand where to improve the Wi-Fi quality, if necessary. It is particularly useful if some categories of students return to campus, while others do not, e.g. as COVID-19 lockdowns ease.
@{424,
author = {V. Mbonye, C. Sue Price},
title = {Students’ use of on-campus wireless networks: Analysis by residence type},
abstract = {Universities supply free Wi-Fi to registered students on campus to access learning materials. Many issues could reduce the quality of students' Wi-Fi use, e.g., devices using different Wi-Fi standards than those used on campus, and numerous students accessing Wi-Fi through a single access point simultaneously. Understanding where, when and how students use Wi-Fi on campus can help IT administrators to provide an adequate Wi-Fi service. This pre-COVID study adopted a mixed method approach. Questionnaires were completed by a representative sample of 373 students on the Westville campus of the University of KwaZulu-Natal, South Africa. Two Information Communication Services (lCS) staff members were interviewed to gain insights into how the Wi-Fi was set up, and their perspectives on how students utilise the Wi-Fi. The questionnaire data were analysed statistically, and interview results were used to explain results. The students' most used venues, and the places they encountered poor and best Wi-Fi signal quality, are presented, along with the durations of use and problems encountered. When analysing these results by students' residence type, each category showed a different pattern of use. These results can help IT administrators understand where to improve the Wi-Fi quality, if necessary. It is particularly useful if some categories of students return to campus, while others do not, e.g. as COVID-19 lockdowns ease.},
year = {2021},
journal = {2021 International Conference on Artificial Intelligence, Big Data, Computing and Data Communication Systems (icABCD)},
month = {5-6/08},
publisher = {IEEE},
address = {Durban, South Africa},
isbn = {978-1-7281-8591-0},
url = {https://ieeexplore.ieee.org/document/9519327},
doi = {https://doi.org/10.1109/icABCD51485.2021.9519327},
}
1.
Price CS, Moodley D, Pillay A. Modelling uncertain adaptive decisions: Application to KwaZulu-Natal sugarcane growers. In: Forum for Artificial Intelligence Research (FAIR2019). Cape Town: CEUR; 2019. http://ceur-ws.org/Vol-2540/FAIR2019_paper_53.pdf.
A dynamic Bayesian decision network was developed to model the preharvest burning decision-making processes of sugarcane growers in a KwaZulu-Natal sugarcane supply chain and extends previous work by Price et al. (2018). This model was created using an iterative development approach. This paper recounts the development and validation process of the third version of the model. The model was validated using Pitchforth and Mengersen (2013)’s framework for validating expert elicited Bayesian networks. During this process, growers and cane supply members assessed the model in a focus group by executing the model, and reviewing the results of a prerun scenario. The participants were generally positive about how the model represented their decision-making processes. However, they identified some issues that could be addressed in the next iteration. Dynamic Bayesian decision networks offer a promising approach to modelling adaptive decisions in uncertain conditions. This model can be used to simulate the cognitive mechanism for a grower agent in a simulation of a sugarcane supply chain.
@{244,
author = {C. Sue Price, Deshen Moodley, Anban Pillay},
title = {Modelling uncertain adaptive decisions: Application to KwaZulu-Natal sugarcane growers},
abstract = {A dynamic Bayesian decision network was developed to model the preharvest burning decision-making processes of sugarcane growers in a KwaZulu-Natal sugarcane supply chain and extends previous work by Price et al. (2018). This model was created using an iterative development approach. This paper recounts the development and validation process of the third version of the model. The model was validated using Pitchforth and Mengersen (2013)’s framework for validating expert elicited Bayesian networks. During this process, growers and cane supply members assessed the model in a focus group by executing the model, and reviewing the results of a prerun scenario. The participants were generally positive about how the model represented their decision-making processes. However, they identified some issues that could be addressed in the next iteration. Dynamic Bayesian decision networks offer a promising approach to modelling adaptive decisions in uncertain conditions. This model can be used to simulate the cognitive mechanism for a grower agent in a simulation of a sugarcane supply chain.},
year = {2019},
journal = {Forum for Artificial Intelligence Research (FAIR2019)},
pages = {145-160},
month = {4/12-6/12},
publisher = {CEUR},
address = {Cape Town},
url = {http://ceur-ws.org/Vol-2540/FAIR2019_paper_53.pdf},
}
1.
Mbonye V, Price CS. A model to evaluate the quality of Wi-Fi perfomance: Case study at UKZN Westville campus. In: 2nd International Conference on Advances in Big Data, Computing and Data Communication Systems (icABCD 2019). Danvers MA: IEEE; 2019.
Understanding how satisfied users are with services is very important in the delivery of quality services and in improving them. While studies have investigated perceptions of Wi-Fi among students, there is still a gap in understanding the overall perception of quality of service in terms of the different factors that may affect Wi-Fi service quality. Brady & Cronin Jr’s service quality model proposes that outcome quality, physical environment quality and interaction quality affect service quality. Sub-constructs for the independent variables were generated, and Likert-scale items developed for each sub-construct, based on the literature. 373 questionnaires were administered to University of KwaZulu-Natal (UKZN) Westville campus students. Factor analysis was to confirm the sub-constructs. Multiple regression analysis was used to test the model’s ability to predict Wi-Fi service quality.
Of the three independent constructs, the outcome quality mean had the highest value (4.53), and it was similar to how the students rated service quality (4.52). All the constructs were rated at above the neutral score of 4. In the factor analysis, two physical environment quality items were excluded, and one service quality item was categorised with the expertise sub-construct of interaction quality. Using multiple regression analysis, the model showed that the independent constructs predict service quality with an R2 of 59.5%. However, when models for individual most-used locations (the library and lecture venues) were conducted, the R2 improved. The model can be used to understand users’ perceptions of outcome quality, physical environment quality and interaction quality which influence the quality of Wi-Fi performance, and evaluate the Wi-Fi performance quality of different locations.
@{217,
author = {V. Mbonye, C. Sue Price},
title = {A model to evaluate the quality of Wi-Fi perfomance: Case study at UKZN Westville campus},
abstract = {Understanding how satisfied users are with services is very important in the delivery of quality services and in improving them. While studies have investigated perceptions of Wi-Fi among students, there is still a gap in understanding the overall perception of quality of service in terms of the different factors that may affect Wi-Fi service quality. Brady & Cronin Jr’s service quality model proposes that outcome quality, physical environment quality and interaction quality affect service quality. Sub-constructs for the independent variables were generated, and Likert-scale items developed for each sub-construct, based on the literature. 373 questionnaires were administered to University of KwaZulu-Natal (UKZN) Westville campus students. Factor analysis was to confirm the sub-constructs. Multiple regression analysis was used to test the model’s ability to predict Wi-Fi service quality.
Of the three independent constructs, the outcome quality mean had the highest value (4.53), and it was similar to how the students rated service quality (4.52). All the constructs were rated at above the neutral score of 4. In the factor analysis, two physical environment quality items were excluded, and one service quality item was categorised with the expertise sub-construct of interaction quality. Using multiple regression analysis, the model showed that the independent constructs predict service quality with an R2 of 59.5%. However, when models for individual most-used locations (the library and lecture venues) were conducted, the R2 improved. The model can be used to understand users’ perceptions of outcome quality, physical environment quality and interaction quality which influence the quality of Wi-Fi performance, and evaluate the Wi-Fi performance quality of different locations.},
year = {2019},
journal = {2nd International Conference on Advances in Big Data, Computing and Data Communication Systems (icABCD 2019)},
pages = {291-297},
month = {05/08 - 06/08},
publisher = {IEEE},
address = {Danvers MA},
isbn = {978-1-5386-9235-6},
}
Research Groups:
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My name is Alex Priscu, and I am a Masters (MSc by Dissertation) student at the University of Cape Town, where I am currently completing a dissertation under the supervision of Dr Deshendran Moodley. I am a member of the Centre for Artificial Intelligence (CAIR) and hold a BSc in Computer Science and Computer Engineering with double distinction, as well as a BSc (Honours) in Computer Science with First Class.
Under the supervision of Dr Hussein Suleman, I conducted research on information systems for my Honours degree, and we successfully implemented the first South African National Heritage Portal Prototype using metadata aggregation. Furthermore, my Masters degree research focuses on machine learning, specifically the topic of "Automated Machine Learning for Solving the Combined Algorithm Search and Hyperparameter Optimisation Problem in Trend Prediction".
Under the supervision of Dr Hussein Suleman, I conducted research on information systems for my Honours degree, and we successfully implemented the first South African National Heritage Portal Prototype using metadata aggregation. Furthermore, my Masters degree research focuses on machine learning, specifically the topic of "Automated Machine Learning for Solving the Combined Algorithm Search and Hyperparameter Optimisation Problem in Trend Prediction".
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