<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Journal of Biomedical Semantics 4 (2013). doi: 10.1186/
2041</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.1007/s12599-019-00595-2</article-id>
      <title-group>
        <article-title>Re-imagining health and well-being in low resource African settings using an augmented AI system and a 3D digital twin</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Deshendran Moodley</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christopher Seebregts</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Centre for Artificial Intelligence Research</institution>
          ,
          <addr-line>Cape Town</addr-line>
          ,
          <country country="ZA">South Africa</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Jembi Health Systems</institution>
          ,
          <addr-line>Tokai, Cape Town</addr-line>
          ,
          <country country="ZA">South Africa</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>University of Cape Town</institution>
          ,
          <addr-line>18 University Avenue, Rondebosch, Cape Town</addr-line>
          ,
          <country country="ZA">South Africa</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2021</year>
      </pub-date>
      <volume>34</volume>
      <fpage>29348</fpage>
      <lpage>29363</lpage>
      <abstract>
        <p>This paper discusses and explores the potential and relevance of recent developments in artificial intelligence (AI) and digital twins for health and well-being in low-resource African countries. We use the case of public health emergency response to disease outbreaks and epidemic control. There is potential to take advantage of the increasing availability of data and digitization to develop advanced AI methods for analysis and prediction. Using an AI systems perspective, we review emerging trends in AI systems and digital twins and propose an initial augmented AI system architecture to illustrate how an AI system can work with a 3D digital twin to address public health goals. We highlight scientific knowledge discovery, continual learning, pragmatic interoperability, and interactive explanation and decision-making as essential research challenges for AI systems and digital twins.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Augmented AI</kwd>
        <kwd>AI in Health</kwd>
        <kwd>Digital Twin</kwd>
        <kwd>PHEOC</kwd>
        <kwd>Pragmatic Interoperability</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Public health aims to prevent disease, promote health, and prolong life among the population. In
the Alma-Ata declaration [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], the World Health Organization (WHO) reafirmed that attaining
the highest possible level of health is the most significant worldwide social goal. Public health
programs strive to optimise the conditions in which people can achieve health and well-being.
      </p>
      <p>
        Low-resource countries bear much of the world’s disease burden and outbreaks [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. They
also lack essential infrastructure and need to maximize the utility of the available resources.
Despite these challenges, African and low-resource countries have made admirable progress in
digitising health systems, resulting in a significant number of surveillance and routine health
information systems. This opens up novel opportunities to leverage advanced computing
techniques such as AI to advance health and well-being in low-resource African countries
[
        <xref ref-type="bibr" rid="ref4">4</xref>
        ][
        <xref ref-type="bibr" rid="ref5">5</xref>
        ].
      </p>
      <p>Modern approaches to health systems and public health in low-resource settings increasingly
focus on preventative in addition to curative health approaches. This leads to a more holistic
perspective on health and well-being. However, preventative health requires a better
understanding of the factors that cause and influence disease onset and the positive and negative
determinants of disease and adverse health conditions. Understanding and promoting healthy
behaviours and lifestyles is a primary goal of digital health systems in African countries.</p>
      <sec id="sec-1-1">
        <title>1.1. One Health and epidemic surveillance</title>
        <p>
          The WHO recommends a One Health approach [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] to design and implement health programmes,
policies, legislation and research. The One Health approach proposes an integrated, unifying
approach to balance and optimize the health of people, animals and the environment. It is
essential to prevent, predict, detect, and respond to global health threats and emergencies such
as the recent COVID-19 pandemic [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ]. The One Health approach mobilizes multiple sectors,
disciplines and communities at varying levels of society to work together to achieve better
public health outcomes. This way, new and better ideas are developed that address root causes
more holistically and create long-term, sustainable solutions to predict adverse health conditions
before they occur. Supporting the One Health approach presents new challenges to digital
health systems [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]. Public health decision-makers integrate several diferent data sources from
diverse digital and paper-based systems to assist with complex decision-making around outbreak
management and epidemic control. These include routine health data systems, surveillance
systems, household and bio-behavioural surveys, and research data. If it is paper-based, the
data must first be digitised, then transformed and compiled into dashboards to optimize public
health situation detection, response and prediction. A One Health digital platform must deal
with new levels of interoperability between diferent jurisdictions and disciplines to connect
vast amounts of heterogeneous data and systems. The platform must support real-time situation
analysis, predictive modelling, and proactive decision-making to reach its full potential.
        </p>
      </sec>
      <sec id="sec-1-2">
        <title>1.2. Health monitoring and digital data management</title>
        <p>
          Surveillance of public health threats is one of the main functions of public health, e.g. in a public
health emergency operations centre (PHEOC) [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ] [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]. Typical activities include monitoring
public health threats in a country, e.g. surveillance of public health threats followed by situation
analysis and decision-making [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ]. Similar challenges are encountered in other vertical disease
areas, such as the attainment of HIV Epidemic Control [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ] [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ]. HIV Epidemic Control Rooms
have been developed to monitor progress towards achieving goals and performance targets.
Traditional information and data sources are changing due to digitization and shifting emphasis
to using information from routine health information systems to derive, monitor and manage
epidemiological targets [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ].
        </p>
        <p>
          Data management processes supporting monitoring, such as semantic annotation and data
integration, are established in practice. In the case of situation analysis, well-established
surveillance methods support detection. Support for prediction from digital health and AI
is emerging with examples such as the digital predictive tool developed for forecasting the
occurrence of diseases based on historical weather and health data in Uganda [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ].
        </p>
      </sec>
      <sec id="sec-1-3">
        <title>1.3. Relevance and potential of AI and digital twins</title>
        <p>Powerful data-driven AI models can be used for dynamic data fusion, situation analysis,
predictive modelling, and scientific knowledge discovery. These are all valuable functions in public
health and can lead to a new understanding of complex dynamic processes. An AI system
working in parallel with a digital twin can augment and amplify interactive decision-making
and scientific knowledge discovery in public health decision-making.</p>
        <p>
          In this position paper, we explore the relevance and potential of artificial intelligence and
digital twins as two key emerging technologies that push the boundaries of the One Health
vision in low-resource public health systems. Our perspective is informed by over a decade of
research and real-world implementation of advanced digital health technologies in multiple
African countries [
          <xref ref-type="bibr" rid="ref15">15</xref>
          ]. Based on our experience, we propose an abstract architecture for an
augmented AI system incorporating a Digital Twin, highlighting the potential for AI and digital
twins to realise the One Health vision. We focus on the potential of AI systems and digital
twins to support scientific knowledge discovery, interactive decision making and pragmatic
interoperability.
        </p>
        <p>The paper is structured as follows. In section 2, we describe digital twins in health care
and then review emerging trends and critical challenges in AI systems in section 3. Section
4 provides a preliminary proposal for an abstract architecture for an augmented AI system
incorporating a digital twin. In section 5, we ofer a brief discussion and conclusions.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. Digital Twins in Health Care</title>
      <p>
        A digital twin is a virtual model of a physical entity, with dynamic, bi-directional links between
the physical entity and its corresponding twin in the digital domain [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. While they have been
traditionally explored in the manufacturing sector, digital twins are increasingly being explored
in medicine and health care [
        <xref ref-type="bibr" rid="ref17 ref18 ref19">17, 18, 19</xref>
        ]. Applied to medicine and public health, digital twin
technology has been proposed to drive a much-needed radical transformation of traditional
electronic health/medical records (focusing on individuals) and their aggregates (covering
populations) to make them ready for a new era of precision (and accuracy) medicine and public
health [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
      <sec id="sec-2-1">
        <title>2.1. Cognitive digital twins</title>
        <p>
          A digital twin augmented with AI capabilities can be called a Cognitive Digital Twin (CDT) [
          <xref ref-type="bibr" rid="ref20 ref21">20,
21</xref>
          ]. Semantic Web technologies, such as ontologies and knowledge graphs, can be incorporated
within DTs to support reasoning and deliberation [
          <xref ref-type="bibr" rid="ref21">21</xref>
          ]. Abburu et al. describe a broader
vision and architecture for a CDT in the process and manufacturing industry [
          <xref ref-type="bibr" rid="ref20">20</xref>
          ]. Their CDT
architecture incorporates cognitive features that will enable sensing complex and unpredicted
behaviour and reason about dynamic strategies for process optimization, leading to a system
that continuously evolves its own digital structure and behaviour.
        </p>
        <p>The CDT evolves into a self-learning and proactive system that will optimize its own cognitive
capabilities over time based on the data it will collect and the experience it will gain. It will find
new answers to emerging questions by combining expert knowledge with the power of Digital
Twins. A CDT will thus achieve synergy between the DT and the expert and problem-solving
expertise. Unlike the process industry, which can be viewed as a closed and bounded system, in
public health, a plethora of digital twins may be developed by diferent organisations and in
other domains with potentially diferent perspectives. A more recent proposal by Ricci et al.
[22, 23] explores and proposes a distributed and open architecture and platform for a Web of
Digital Twins. They describe an open ecosystem of multiple digital twins possibly belonging
to diferent domains and organisations. The open-distributed system perspective aligns well
with the One Health perspective for low-resource African countries. Population, clinical, vital
statistics, e.g. births and deaths, and geospatial and environmental data may be stored in
diferent systems across diferent government departments, possibly with other systems at the
facility, city, district, state and country levels.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. Digital twins for healthcare and well-being</title>
        <p>
          Several recent studies have explored digital twins for healthcare [
          <xref ref-type="bibr" rid="ref17">17, 24, 25</xref>
          ]. The most common
approach is to use DTs for precision medicine [
          <xref ref-type="bibr" rid="ref17 ref18">17, 18</xref>
          ] where healthcare practice shifts from
being primarily reactive to a more preventative approach. Many studies highlighted the higher
complexity of designing digital twins for health care compared to digital twins in manufacturing
and industry.
        </p>
        <p>
          Ahmadi-Assalemi et al [
          <xref ref-type="bibr" rid="ref17">17</xref>
          ] highlighted diferent types of support that DTs must provide at
varying levels of the healthcare system, i.e. individual level, healthcare professional level, and
health system level. At the individual level, a patient’s complex needs may influence real-time
behaviours, feelings, adherence to the set targets and the utilization of healthcare services. They
propose a more ambitious definition of health as the state of complete well-being, including the
physical, mental, and social aspects in addition to the biomedical one. This proactive patient
care aims to preempt the disease through preventative medicine and early detection, which
could change the societal culture by empowering individuals to prevent their own disease. They
note that many factors that afect a person’s well-being and condition, including environmental,
demographic, socioeconomic or biological, in a constantly changing landscape, are not detected
during routine health screening.
        </p>
        <p>
          Kamel-Boulos et al suggested a role for Digital twins in precision public health and disease
outbreaks potentially integrated as part of a health city [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ]. The suggested systems could
include advanced systems for case management and case finding as well as determining risk
levels in particular geographic areas [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ].
        </p>
        <p>Hassani et al [24] highlight the complexity of healthcare and propose diferent digital twins
for the various life stages of a person. They argue that digital twins can be used to combat
healthcare inequality, improve operational eficiencies of healthcare facilities and accelerate
advances in healthcare research. They also highlight the need for further research on the
interactions between digital twins and AI. More in-depth reviews of digital twins in healthcare
can be found in [26, 27, 28].</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. AI systems</title>
      <p>In this section, we provide an overview of emerging trends and future directions for AI systems
in the context of the One Health vision. Next-generation AI systems must support
scientific knowledge discovery, complex social and behavioural modelling, decision making and
simulation.</p>
      <sec id="sec-3-1">
        <title>3.1. Augmented AI systems</title>
        <p>Our perspective of AI aligns closely with the notion of augmented AI [29, 30], which more
recently is being referred to as Hybrid Intelligence [31, 32]. In augmented AI, the AI system
amplifies human cognition rather than replacing it. As such the human user, in this case the
public health practitioner, works interactively and cooperatively with the system.</p>
        <p>An augmented AI system can be characterised as an adaptive and cognitive system. The
adaptive characteristic presents broader challenges beyond merely dealing with changes
emanating from dynamic environments. To better describe this interaction, we use the word
agent as a personification of the system from the user’s perspective. From the human user
perspective, the agent forms the communication interface between the system and the user. For
human-agent interaction to be efective, the user must be able to specify their knowledge about
the environment and decision-making context to the agent.</p>
        <p>The agent’s knowledge base and reasoning processes constitute a shared model reflecting
both the system’s and the user’s knowledge, reasoning and decision-making processes. This
shared model serves as a basis for communication and interaction between the user and the
system. The user may initially specify goals and objectives which are incomplete and vague.
These will also change and evolve naturally over time as the agent adapts to the user and the user
to the agent. Even though the agent may incorporate diferent inference algorithms, the agent
must be able to follow reasoning patterns compatible with and understandable by the human
user within their application context. In this way, the rationale and analysis of any decision
recommendation can efectively be communicated and explained to the user. The human user
can ask the question, “Why would I do this?” or “How did you arrive at this conclusion?”. As
such, an agent must convince the user that the action it recommends is the best one to take
after analysing all the information at hand.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Scientific knowledge discovery</title>
        <p>The One Health approach proposes an integrated, unifying approach to balance and optimize
the health of people, animals and the environment. It will leverage scientific understanding
and theories in the earth, biological and behavioural sciences. Physical, biological and social
processes are constantly evolving and depend on dynamic micro-scale and meso-scale
environments [33]. Processes may vary significantly at diferent locations and typically change over
time. Subsequently, theoretical positions difer significantly and may even be contradictory. An
integral part of data analysis and scientific enquiry is the application of diferent theories to
analyse incoming observations. Well-founded and established theories can be incorporated into
modelling, simulation and decision-support tools. In contrast, new theories can be constantly
adapted and evaluated against incoming observations to test their validity. Moreover, powerful
Artificial Intelligence (AI) data mining and pattern analysis techniques can be continuously
applied to data over time to capture new patterns, formulate new theories and refine existing
theories. Ultimately the scientific community should publish dynamic and formal models of
their theories and validation data online for immediate dissemination and reproducibility. This
has the potential to accelerate and reduce the cost and efort for scientific discovery and lower
the barrier for decision-makers to access the latest data analysis and simulation models to
improve their planning and inform policy.</p>
        <p>AI-driven knowledge discovery systems will have the capacity to pursue scientific research,
collect measurements, find regularities, form hypotheses, and gather additional data to test
them [34]. Like humans these continual learning systems [35] will learn incrementally and
cumulatively. Key functions will include taxonomy formation, descriptive law induction and
explanatory model construction [34]. These systems would engage in all of these scientific
activities, each of which can involve detecting and responding to anomalous observations.
While these systems may act autonomously [34], a more compelling vision is for them to work
in tandem with human researchers as a fully functional member of a research team. There are
three fundamental functional areas where AI can contribute to new scientific understanding
[36]. First, AI can act as an instrument revealing properties of a physical system that are
dificult or even impossible to probe. Humans then use these insights to formulate new scientific
understanding. Second, AI can act as a source of inspiration for new concepts and ideas that
are subsequently understood and generalized by human scientists. Third, AI acts as an agent
to create new understanding. AI reaches new scientific insight and can transfer it to human
researchers.</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. Knowledge based approaches</title>
        <p>Generating hypotheses and maintaining a consistent body of knowledge in science is a
formidable task due to the vast number of hypotheses generated and maintained, and the
complexity, non-monotonicity, uncertainty and unreliability of knowledge and data published
[37]. Logic-based concept ontologies emanating from the Semantic Web community have been
widely used to represent, and reason about concepts and relations in a domain [38]. Ontology
languages like OWL are typically based on monotonic logic such as Description Logics and
provide limited support to deal with uncertainty and non-monotonicity. While they can
efectively capture both syntax and semantics to enable communication, they are limited in terms of
capturing and representing pragmatics, i.e., the context in which the knowledge is used [39, 40].
Ontologies can enable semantic interoperability, but not pragmatic interoperability between
agents [41]. Casanovas [42] argue that social context is crucial and that meaning is only fully
realised in actual situations assuming an interactional and dynamic notion of context. A further
limitation is the lack of explicit support for representing decision-making processes.</p>
        <sec id="sec-3-3-1">
          <title>3.3.1. Bayesian Networks and frameworks</title>
          <p>Bayesian Networks (BNs) are highly efective causal models that aim to capture human
reasoning and decision-making in uncertain situations [43]. They support three diferent types
of explanations [44]. For the explanation of the evidence, an abduction inference process is
typically used to obtain the most probable explanation (MPE) explanation of the evidence. The
purpose of this kind of explanation is to ofer a diagnosis for a set of observed anomalies.
Explanation of the model consists of displaying the information contained in the knowledge base and
allows experts to easily navigate the knowledge. Explanation of reasoning provides justification
for inferences made by the system. It allows users to understand and check the correctness of
the reasoning process and the inferences made by the system. Compared to a rule-based expert
system with IF-THEN rules, BNs are more compatible with present thinking about explanation
[45]. However, it is neither clear how explanations in BNs can capture pragmatics, nor how to
operationalise explanatory virtues in the context of BNs [45].</p>
          <p>In philosophy, the conventional rational choice model of decision-making (based upon
expected utility maximization), is widely discussed and used [46]. Bayesian Decision Networks
(BDN), which are based on expected utility maximisation, are widely used for representing
decision-making processes. Fareh [47] discusses how Bayesian Networks (BN) can be combined
with ontologies to represent incomplete knowledge and uncertainty to predict liver cancer.
BDNs also incorporate uncertainty and can recommend decisions where there is incomplete
knowledge. However, rational choice can be viewed as a prescriptive model, a way of specifying
how individuals ought to behave, rather than how they actually behave. Human behaviour can
also be impacted by emotion, mood, personality, needs and subjective well-being. Abaalkhail
[48] reviews current ontologies for afective states (emotion and mood). These ontologies
can be used to build decision-support systems that consider emotion and mood. In a recent
review paper, Barthès [49] explored decision-making mechanisms for ethical decision-making
in cognitive agents. He highlights uncertainty and incomplete knowledge as key issues that
must be taken into account. He provides a preliminary computational framework that takes
into account diferent factors that influence human decision-making, including emotion and
mood. This can be used as a foundation to design and analyse empathetic agents that are better
able to support human decision-making.</p>
        </sec>
        <sec id="sec-3-3-2">
          <title>3.3.2. Explanation in AI systems</title>
          <p>Knowledge discovery, cognition, communication, decision making and explanation are integrally
linked. In their recent papers, Chari et al [50, 51] provide an excellent analysis of explanation
in knowledge-based AI systems. They identify nine types of explanation [50] in AI systems
and highlight the need for AI systems to present personalized, trustworthy, and context-aware
explanations to users. Our view is that a 3D virtual twin can provide a visual explanation in
both space and time and is grounded in a pseudo-reality. We consider this as a new type of
explanation. This is linked to the notion of pragmatic and social world communication. A 3D
virtual digital twin can provide a rich context for communicating predictions, theories and
beliefs posed by the AI system. It provides the outputs and deliberations of the AI system to be
rendered in a pseudo-reality for further analysis.</p>
        </sec>
      </sec>
      <sec id="sec-3-4">
        <title>3.4. Continual learning</title>
        <p>Continual learning, also known as incremental learning or lifelong learning, is an increasingly
relevant area of study that asks how artificial systems might learn sequentially, as biological
systems do, from a continuous stream of data [35, 52, 53]. Unlike, traditional Deep Neural
Network (DNN) tasks that rely on fixed datasets and stationary environments, the problem of
continual learning is defined by a sequential training protocol and by the features expected
from the solution. In contrast to the common machine learning setting of a static dataset or
environment, the continual learning setting explicitly focuses on non-stationary or changing
environments. Continual learning systems must deal with temporal generalisation, change
detection and mechanisms for a model update, specifying and aligning expected features and
loss functions, and appropriate validation and data partitioning methods. While some of these
issues have been explored, e.g. prequential or walk-forward validation in time series forecasting
[54], and more recently temporal generality in language models [55], this is still an emerging
area with many open challenges.</p>
        <p>Spatial Temporal Graph Neural Networks (ST-GNN) are a new wave of advanced DNN
techniques, which have emerged recently to model and predict flow in complex systems [ 56].
Typical characteristics are high frequency and noisy observations from multiple sensors with
complex and often latent spatial and temporal dependencies. While the canonical application is
for trafic flow in a city, these techniques have wider applications for modelling dynamic systems
in general, for example, weather modelling [57]. Weather prediction has a higher complexity
than the trafic problem. Unlike trafic flow prediction which models a single variable, i.e. trafic
speed at diferent points in a city, weather prediction involves many diferent weather variables
at diferent temporal and spatial scales. A key feature of ST-GNNs is that they dynamically learn
complex spatial-temporal dependencies inherent in the data and capture this in an adjacency
matrix. These dependencies can be used as the foundation for constructing causal theories
in the domain. We believe that ST-GNNs are at the frontier of learning-based approaches for
knowledge discovery, predictive modelling and explanation in dynamic environments.</p>
      </sec>
      <sec id="sec-3-5">
        <title>3.5. Architectures for scientific knowledge discovery systems</title>
        <p>AI systems for scientific knowledge discovery are introduced in section 3.2. In this section we
explore some of the architectures for such systems. Systems that can contribute to new scientific
understanding are certainly on the frontier of AI [34, 36, 37]. A compelling vision for the field is
to design an “AI scientist” that works in tandem with human researchers as a fully functioning
member of a research team. This overlaps with the notion of hybrid intelligence and augmented
intelligence systems where the machine works in collaboration with and cooperatively with the
human user [58, 31]. Hybrid intelligence systems for knowledge discovery have been explored
recently by Gil in her position paper on “Thoughtful Artificial Intelligence Systems” [ 59] where
she proposes seven principles for such systems and sets an agenda for research in this area.</p>
        <sec id="sec-3-5-1">
          <title>3.5.1. Ontology driven systems</title>
          <p>One of the first examples of knowledge discovery systems is the Robot Scientist [ 60]. The
Robot Scientist is a semantic architecture that incorporates the LABORS ontology. More recent
eforts are DISK [ 61] and HELO [62]. In the HELO study [62] the representation of uncertainty
is identified as a key limitation of previous ontology-driven knowledge discovery systems.
HELO explicitly targets this limitation and Bayesian probability is incorporated into the HELO
ontology to represent the current belief or uncertainty of diferent research statements or
hypotheses. The uncertainty of research statements is updated as new evidence arises, forming
the basis for decision-making during the research process. This aligns with our previous
work where we found that a knowledge engineering approach that uses ontologies alone has
substantial limitations in real-world applications. Based on our experience in four studies
in South Africa across diverse domains and user communities, i.e. earth observation [33],
health [63], biodiversity [64], and finance [ 65], we found that an approach that combines both
ontologies and Bayesian decision networks to be highly efective to deal with these challenges.
While ontologies are ideal for representing and structuring domain knowledge, Bayesian decision
networks (BDN) provide explicit support for reasoning with uncertainty, and for capturing and
reasoning about decision-making processes.</p>
        </sec>
        <sec id="sec-3-5-2">
          <title>3.5.2. Emerging architectures based on Philosophy of Science</title>
          <p>Understanding scientific method is essential for designing knowledge discovery systems. Various
theories of scientific method have been proposed in Philosophy of Science, for example, the
inductive theory and the hypothetico-deductive theory of methods. The scientific Abductive
Theory of Method (ATOM) [66, 67] is a recent theory that is more encompassing and detailed
and is compatible with current thinking around knowledge discovery in the AI community [34,
36, 37] (described above). ATOM consists of two overarching processes, namely i) phenomenon
detection where novel or anomalous patterns are detected in data, and ii) theory construction
where plausible theories are generated and evaluated to explain detected phenomena. In recent
work [68], we explored a generic architecture for a knowledge discovery agent based on ATOM.
There are many advantages for grounding the architecture in ATOM. It will more closely align
with the process that researchers actually use making it more human-centred. It provides an
abstract architecture that incorporates both data-driven and knowledge-based AI approaches
described above. It also provides an entry point to the large body of recent work emanating
from the Philosophy of Science community on theory construction. Haig suggests the use of
analogical reasoning for theory construction and for assessing explanations [66]. Confirmation
based on analogical inference using a Bayesian framework is currently being explored in the
Philosophy of Science community [69, 70]. Analogical inference is related to the notion of
transfer learning in the machine learning community. This is particularly important in
lowresource settings where large clinical data sets may not be available. Machine learning models
may be training initially on large data sets from diverse populations in the developed world and
then fine tuned on smaller data sets in low resource African countries. An initial exploration of
transfer learning to detect heart disease in diverse populations from ECG signals can be found
in [71].</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. An architecture for an AI-driven digital twin system</title>
      <p>We propose an initial abstract architecture for an augmented AI system in figure 1. The
architecture draws from and extends the ideas presented in Wanyana and Moodley’s KDE Agent
architecture [68], Russell and Norvig’s learning agent [72] and Ricci et al’s WoDT [22]. The
AI system augments the 3D digital twin and uses it as a key platform for its simulations, for
knowledge discovery and ultimately to augment the human user, in this case, the public health
decision maker.</p>
      <sec id="sec-4-1">
        <title>4.1. System overview</title>
        <p>The system will continuously interrogate vast quantities of heterogeneous observational data,
automatically generate and maintain internal models to explain evolving phenomena, evaluate
these models through simulation in the DT and in cooperation with the user, discover a new
understanding of evolving phenomena and provide possible courses of actions to achieve the
goals set by the human user.</p>
        <p>The system maintains two views of the world which connect it to the user and the physical
world. The Cognitive view maintains a model of the user, i.e. the beliefs, goals and decision
paths of the public health decision-maker. The Physical view encompasses the 3D digital world,
which is used to model a pseudo-reality of the physical world, including properties of physical
entities, and interactions and behaviours of individuals and populations.</p>
        <p>Adaptation and cognition are two essential functional areas of the system. The adaptive
characteristic is concerned with rapid learning and model updates when the world changes,
communicating new information about the environment to the user and adjusting to changes
in the user’s decision-making goals and preferences as the user learns and adjusts to the system.
The cognitive characteristic involves the use of representing prior knowledge, world dynamics
and appropriate reasoning mechanisms for sense-making and belief update and revision that is
aligned to human reasoning. The cognitive aspect facilitates the overall interactions with the
user and provides explicit support for providing explanations and allows the user to interrogate
courses of action recommended by the system.</p>
        <p>The abstract architecture consists of three layers, i.e. the Monitoring Layer, the Situation
Analysis Layer and the Augmentation Layer</p>
      </sec>
      <sec id="sec-4-2">
        <title>4.2. Monitoring Layer</title>
        <p>At the Monitoring Layer, ontologies will be used for semantic data annotation and data fusion.
Data will include earth observation data, clinical data, population data, behavioural data and
clinical data. Existing semantic architectures from our previous work in earth observation [33]
and biodiversity [64] will be leveraged for semantic mediation and dynamic data fusion.</p>
        <p>The Sensor Web Agent Platform (SWAP) architecture [33] proposes a three-layered open
distributed system architecture and a conceptual knowledge representation and reasoning
framework that integrates ontologies and Bayesian networks for developing distributed Sensor
Web applications. The SWAP semantic architecture provides modular ontologies for reasoning
about space, time, theme (the entity and properties being observed) and uncertainty and supports
semantic annotation and dynamic data fusion from heterogeneous sensor data. Coetzer et al
[64] explored a semantic architecture for a knowledge-based system that uses expert knowledge
to generate ecological interaction networks from distributed and heterogeneous natural history
occurrence data. The system builds on the SWAP architecture and introduces a biodiversity
mapping ontology that supports semantic annotation and fusion of heterogeneous data from
three biodiversity databases hosted by diferent museums across South Africa.</p>
        <p>The 3D digital twin provides a pseudo-reality of the physical world. Observational data stored
in databases in existing systems together with real-time sensor observations will be semantically
annotated, fused and rendered in the 3D digital twin. The fused observations are contextualised
within the 3D world and must be harmonised and logically consistent with other observations,
entities and processes that are unfolding in the 3D world. The 3D world thus provides context
for and guides data fusion and is integral to achieving pragmatic interoperability.</p>
      </sec>
      <sec id="sec-4-3">
        <title>4.3. Situation Analysis</title>
        <p>This layer consists of two components. Situation detection can use ontologies, semantic rules,
fuzzy rules and Bayesian networks for detecting current situations. Semantic technologies
are increasingly being used for situation analysis in personal health monitoring systems that
incorporate wearable sensors [73]. Bayesian networks can be used for situation analysis and
root cause analysis to support clinical diagnosis [74]. They can be supplemented by machine
learning, e.g. ST-GNNs for flow prediction for early detection of adverse events.</p>
        <p>Ontologies and Bayesian networks can be combined for behavioural modelling and risk
analysis, based on an approach we used in our previous work on analysing the risk of
nonadherence behaviour for medical treatment for tuberculosis patients [63].</p>
      </sec>
      <sec id="sec-4-4">
        <title>4.4. Augmentation Layer</title>
        <p>The Augmentation Layer has three functional components. Similarly to the CDT, the system
augments the DT and in turn augments the user. This tridirectional augmentation is a crucial
aspect of the architecture. Each environment evolves separately, but feedback loops between
the user, the DT and the AI system allow for synchronisation and alignment.</p>
        <p>The system maintains the current beliefs in a knowledge base. It uses continual learning,
e.g. STGNNs, for discovering novel spatial-temporal patterns or new phenomena. This triggers
the theory construction module, which attempts to find explanations for the phenomena. If
there is no suitable explanation, it uses 3D simulation in the DT to better understand the
nature and possible root causes of the novel phenomena. These possible explanations form
new unconfirmed theories that must be further explored. The latest theories are exposed to
the user in the DT for further analysis and input. The user can prioritise theories or propose
alternate theories not discovered by the system. The critic module, similar to the critic module
in Russell &amp; Norvigs Learning Agent [72], provides internal evaluation and analysis of new
theories. It prioritises theories aligned with the user’s goals and uses the DT to evaluate theories
by integrating knowledge from diferent contexts and perspectives.</p>
        <p>The key notion is explicitly modelling the human decision maker’s mental models, i.e. the
Cognitive view. We see the digital twin as capturing physical notions, but the specification
of beliefs, goals, decisions, and knowledge are abstract notions which we separate from the
physical representation. The physical representation (Physical view) not only models properties
of physical entities but also interactions and behaviours of individual people and populations.</p>
        <p>The architecture for an AI-driven digital twin system shown in Figure 1 aligns with the public
health decision-making process in a PHEOC, described in section 1.2. An AI-driven digital twin
can represent and support diferent activities and, in addition, provide enhanced support for
predictive analytics, knowledge discovery and interactive decision-making.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>5. Discussion and conclusion</title>
      <p>This paper describes an ambitious and bold vision to harness the potential of artificial intelligence
and digital twins to re-imagine public health in African countries. A future digital platform
for One Health will have to overcome both social and technical challenges. An open and
distributed One Health platform must mediate between many heterogeneous systems which
manage population, clinical, vital statistics, geospatial and environmental data across diferent
government departments at the facility, city, district, state and country levels.</p>
      <p>The application of Digital Twins to public health shows much promise in LMICs. An
opportunity exists to use a 3D digital twin to mediate and contextualise diferent data sources,
models and systems from a public health perspective. This could include dynamic fusion and
harmonisation of multiple information sources and models in an open distributed environment
with diferent contributors and users. Equipped with AI, the system could also provide
predictive modelling and risk profiling to mitigate disease outbreaks and support early warning
systems for adverse health conditions. The digital twin provides a powerful visual analysis
and simulation tool for investigating and explaining the root causes of events of interest in
public health. However, it will be important to understand the ethical implications of these
approaches.</p>
      <p>To truly unleash the power of these emerging technologies would require a continental-scale
efort and buy-in across multiple African countries, ministries of health, international donors,
universities and non-governmental organisations. Establishing standards and platforms and
an ecosystem to support this vision will indeed be challenging, especially in low-resource
environments. The structure of the ecosystem must balance long-term sustainability, provide
a clear vision, and must be resilient to changing technologies and organisational changes in
the health system. Based on our previous experience in the public health sector our view is
that a middle-out strategy [75] should be considered for structuring such an ecosystem. In
such a middle-out approach, a central authority, such as the national government, manages and
provides leadership in setting standards, the platform architecture and the overall direction
while still allowing autonomy for participating organisations to implement and manage their
own systems.
[22] A. Ricci, A. Croatti, S. Mariani, S. Montagna, M. Picone, Web of Digital Twins, ACM</p>
      <p>Transactions on Internet Technology 22 (2022) 1–30. doi:10.1145/3507909.
[23] A. Ricci, A. Croatti, S. Montagna, Pervasive and Connected Digital Twins - A Vision
for Digital Health, IEEE Internet Computing 26 (2022) 26–32. doi:10.1109/MIC.2021.
3052039.
[24] H. Hassani, X. Huang, S. MacFeely, Impactful Digital Twin in the Healthcare Revolution,</p>
      <p>Big Data and Cognitive Computing 6 (2022). doi:10.3390/bdcc6030083.
[25] D. Chen, N. A. AlNajem, M. Shorfuzzaman, Digital twins to fight against COVID-19
pandemic, Internet of Things and Cyber-Physical Systems 2 (2022) 70–81. doi:10.1016/
j.iotcps.2022.05.003.
[26] N. P. Rocha, A. Dias, G. Santinha, M. Rodrigues, A. Queirós, C. Rodrigues, Smart Cities
and Public Health: A Systematic Review, in: Procedia Computer Science, volume 164,
Elsevier B.V., 2019, pp. 516–523. doi:10.1016/j.procs.2019.12.214.
[27] A. Khan, M. Milne-Ives, E. Meinert, G. E. Iyawa, R. B. Jones, A. N. Josephraj, A Scoping
Review of Digital Twins in the Context of the Covid-19 Pandemic, Biomedical Engineering
and Computational Biology 13 (2022). doi:10.1177/11795972221102115.
[28] S. Elkefi, O. Asan, Digital Twins for Managing Health Care Systems: Rapid Literature</p>
      <p>Review, 2022. doi:10.2196/37641.
[29] N. n. Zheng, Z. y. Liu, P. j. Ren, Y. q. Ma, S. t. Chen, S. y. Yu, J. r. Xue, B. d. Chen, F. y. Wang,
Hybrid-augmented intelligence: collaboration and cognition, 2017. doi:10.1631/FITEE.
1700053.
[30] K. L. A. Yau, H. J. Lee, Y. W. Chong, M. H. Ling, A. R. Syed, C. Wu, H. G. Goh, Augmented
Intelligence: Surveys of Literature and Expert Opinion to Understand Relations between
Human Intelligence and Artificial Intelligence, IEEE Access 9 (2021) 136744–136761.
doi:10.1109/ACCESS.2021.3115494.
[31] Z. Akata, D. Balliet, M. De Rijke, F. Dignum, V. Dignum, G. Eiben, A. Fokkens, D. Grossi,
K. Hindriks, H. Hoos, H. Hung, C. Jonker, C. Monz, M. Neerincx, F. Oliehoek, H. Prakken,
S. Schlobach, L. Van Der Gaag, F. Van Harmelen, H. Van Hoof, B. Van Riemsdijk,
A. Van Wynsberghe, R. Verbrugge, B. Verheij, P. Vossen, M. Welling, A Research
Agenda for Hybrid Intelligence: Augmenting Human Intellect with Collaborative,
Adaptive, Responsible, and Explainable Artificial Intelligence, Computer 53 (2020) 18–28.
doi:10.1109/MC.2020.2996587.
[32] W. Zhang, H. Ning, L. Liu, Q. Jin, V. Piuri, Guest Editorial: Special Issue on Hybrid
Human</p>
      <p>Artificial Intelligence for Social Computing, 2021. doi: 10.1109/TCSS.2021.3049702.
[33] D. Moodley, I. Simonis, J. Tapamo, Architecture for managing knowledge and system
dynamism in the worldwide sensor web, International Journal on Semantic Web and
Information Systems 8 (2012). doi:10.4018/jswis.2012010104.
[34] P. Langley, Agents of exploration and discovery (2021). doi:10.1609/aaai.12021.
[35] R. Hadsell, D. Rao, A. A. Rusu, R. Pascanu, Embracing Change: Continual Learning in</p>
      <p>Deep Neural Networks, 2020. doi:10.1016/j.tics.2020.09.004.
[36] M. Krenn, R. Pollice, S. Y. Guo, M. Aldeghi, A. Cervera-Lierta, P. Friederich, G. dos
Passos Gomes, F. Häse, A. Jinich, A. K. Nigam, Z. Yao, A. Aspuru-Guzik, On scientific
understanding with artificial intelligence, Nature Reviews Physics 4 (2022) 761–769.
doi:10.1038/s42254-022-00518-3.
[37] H. Kitano, Nobel Turing Challenge: creating the engine for scientific discovery, 2021.</p>
      <p>doi:10.1038/s41540-021-00189-3.
[38] P. Hitzler, Semantic Web: A Review Of The Field (2020). URL: https://doi.org/10.1145/
nnnnnnn. doi:10.1145/nnnnnnn.
[39] M. Schoop, A. De Moor, Dietz Jan L G, pragmatic-web-2006-manifesto, Communications
of the ACM 49 (2006).
[40] M. Singh, The Pragmatic Web, IEEE Internet Computing 6 (2002) 4–5. URL: http://computer.</p>
      <p>org/internet/.
[41] F. W. Neiva, J. M. N. David, R. Braga, F. Campos, Towards pragmatic interoperability to
support collaboration: A systematic review and mapping of the literature, Information
and Software Technology 72 (2016) 137–150. doi:10.1016/j.infsof.2015.12.013.
[42] P. Casanovas, V. Rodr\’\iguez-Doncel, J. González-Conejero, The role of pragmatics in
the web of data, in: Pragmatics and Law, Springer, 2017, pp. 293–330. doi:10.1007/
978-3-319-44601-1{\_}12.
[43] K. B. Korb, A. E. Nicholson, Bayesian artificial intelligence, CRC press, 2010.
[44] C. Lacave, F. J. Díez, A review of explanation methods for Bayesian networks, 2002.</p>
      <p>doi:10.1017/S026988890200019X.
[45] M. Tesic, U. Hahn, Explanation in AI systems, in: Human-Like Machine Intelligence, Oxford</p>
      <p>University Press, 2021, pp. 114–136. doi:10.1093/oso/9780198862536.003.0006.
[46] Briggs R A, Normative theories of rational choice: Expected utility. Available online: , 2014.</p>
      <p>URL: https://plato.stanford.edu/entries/rationality-normative-utility/.
[47] M. Fareh, Modeling incomplete knowledge of semantic web using Bayesian
networks, Applied Artificial Intelligence 33 (2019) 1022–1034. doi: 10.1080/08839514.
2019.1661578.
[48] R. Abaalkhail, B. Guthier, R. Alharthi, A. E. Saddik, Survey on Ontologies for Afective
States and Their Influences, Technical Report, ???? URL: http://tomdrummond.com/
leading-and-caring-.
[49] J. P. A. Barthes, Cognitive Agents and Ethical Behavior in Collaborative Teams, in:
Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics,
volume 2020-October, Institute of Electrical and Electronics Engineers Inc., 2020, pp. 3776–
3781. doi:10.1109/SMC42975.2020.9282936.
[50] S. Chari, D. M. Gruen, O. Seneviratne, D. L. McGuinness, Directions for Explainable</p>
      <p>Knowledge-Enabled Systems (2020). URL: http://arxiv.org/abs/2003.07523.
[51] S. Chari, D. M. Gruen, O. Seneviratne, D. L. McGuinness, Foundations of Explainable</p>
      <p>Knowledge-Enabled Systems (2020). URL: http://arxiv.org/abs/2003.07520.
[52] D. L. Silver, Q. Yang, L. Li, Lifelong Machine Learning Systems: Beyond Learning
Algorithms, Technical Report, 2013. URL: www.aaai.org.
[53] G. M. van de Ven, T. Tuytelaars, A. S. Tolias, Three types of incremental learning, Nature</p>
      <p>Machine Intelligence 4 (2022) 1185–1197. doi:10.1038/s42256-022-00568-3.
[54] V. Cerqueira, L. Torgo, I. Mozetič, Evaluating time series forecasting models: an empirical
study on performance estimation methods, Machine Learning 109 (2020) 1997–2028.
doi:10.1007/s10994-020-05910-7.
[55] A. Lazaridou, A. Kuncoro, E. Gribovskaya, D. Agrawal, A. Liška, T. Terzi, M. Gimenez,
C. de Masson, T. Kocisky, S. Ruder, D. Yogatama, K. Cao, S. Young, P. Blunsom, Mind the Gap:
[70] C. J. Feldbacher-Escamilla, A. Gebharter, Confirmation Based on Analogical Inference:
Bayes Meets Jefrey, Canadian Journal of Philosophy 50 (2020) 174–194. doi: 10.1017/
can.2019.18.
[71] S. Aarons, D. Moodley, M. Nzomo, A Generalizable Hybrid Deep Learning Algorithm for
the Detection of Atrial Fibrillation from Diverse Electrocardiogram Data, Technical Report,
University of Cape Town, Cape Town, 2022. URL: https://projects.cs.uct.ac.za/honsproj/
cgi-bin/view/2022/aarons_fisher_rosenthal.zip/deliverables/finalpapershai.pdf.
[72] S. Russell, P. Norvig, Artificial intelligence: A modern approach, Prentice-Hall, Englewood</p>
      <p>Clifs, NJ, 2009.
[73] M. Nzomo, D. Moodley, Semantic Technologies in Sensor-Based Personal Health
Monitoring Systems: A Systematic Mapping Study (2023). URL: http://arxiv.org/abs/2306.04335.
[74] T. Wanyana, M. Nzomo, C. S. Price, D. Moodley, Combining Machine Learning and
Bayesian Networks for ECG Interpretation and Explanation, in: International Conference
on Information and Communication Technologies for Ageing Well and e-Health, ICT4AWE
- Proceedings, Science and Technology Publications, Lda, 2022, pp. 81–92. doi:10.5220/
0011046100003188.
[75] T. Mudaly, D. Moodley, A. Pillay, C. Seebregts, Architectural frameworks for developing
national health information systems in low and middle income countries, in: Proceedings
of the 1st International Conference on Enterprise Systems, ES 2013, 2013. doi:10.1109/
ES.2013.6690083.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1] WHO,
          <string-name>
            <surname>Declaration of</surname>
          </string-name>
          Alma-Ata,
          <source>Technical Report</source>
          ,
          <year>1978</year>
          . URL: https://www.who.int/ publications/i/item/WHO-EURO-1978
          <string-name>
            <surname>-</surname>
          </string-name>
          3938-43697-61471.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2] WHO, World Health Statistics
          <year>2021</year>
          (
          <year>2021</year>
          ). URL: https://apps.who.int/iris/bitstream/handle/ 10665/342703/9789240027053-eng.pdf.
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>M. M. Coates</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          <string-name>
            <surname>Ezzati</surname>
            ,
            <given-names>G. R.</given-names>
          </string-name>
          <string-name>
            <surname>Aguilar</surname>
            ,
            <given-names>G. F.</given-names>
          </string-name>
          <string-name>
            <surname>Kwan</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          <string-name>
            <surname>Vigo</surname>
            ,
            <given-names>A. O.</given-names>
          </string-name>
          <string-name>
            <surname>Mocumbi</surname>
            ,
            <given-names>A. E.</given-names>
          </string-name>
          <string-name>
            <surname>Becker</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <string-name>
            <surname>Makani</surname>
            ,
            <given-names>A. A.</given-names>
          </string-name>
          <string-name>
            <surname>Hyder</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          <string-name>
            <surname>Jain</surname>
            ,
            <given-names>D. Cristina</given-names>
          </string-name>
          <string-name>
            <surname>Stefan</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          <string-name>
            <surname>Gupta</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          <string-name>
            <surname>Marx</surname>
          </string-name>
          , G. Bukhman,
          <article-title>Burden of disease among the world's poorest billion people: An expert-informed secondary analysis of Global Burden of Disease estimates</article-title>
          ,
          <source>PLoS ONE 16</source>
          (
          <year>2021</year>
          ). doi:
          <volume>10</volume>
          .1371/journal. pone.
          <volume>0253073</volume>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>B.</given-names>
            <surname>Natifu</surname>
          </string-name>
          ,
          <source>Climate Change and Health in Sub-Saharan Africa: The Case of Uganda, Technical Report</source>
          ,
          <year>2020</year>
          . URL: https://www.cif.org/sites/cif_enc/files/knowledge-documents/final_ chasa
          <source>_report_19may2020.pdf.</source>
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>T.</given-names>
            <surname>Ciecierski-Holmes</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Singh</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Axt</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Brenner</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Barteit</surname>
          </string-name>
          ,
          <article-title>Artificial intelligence for strengthening healthcare systems in low- and middle-income countries: a systematic scoping review</article-title>
          ,
          <year>2022</year>
          . URL: https://www.nature.com/articles/s41746-022-00700-y. doi:
          <volume>10</volume>
          . 1038/s41746-022-00700-y.
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>The</given-names>
            <surname>Lancet</surname>
          </string-name>
          ,
          <article-title>One Health: a call for ecological equity</article-title>
          ,
          <year>2023</year>
          . doi:
          <volume>10</volume>
          .1016/S0140-
          <volume>6736</volume>
          (
          <issue>23</issue>
          )
          <fpage>00090</fpage>
          -
          <lpage>9</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>K. E.</given-names>
            <surname>Worsley-Tonks</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. B.</given-names>
            <surname>Bender</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S. L.</given-names>
            <surname>Deem</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A. W.</given-names>
            <surname>Ferguson</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E. M.</given-names>
            <surname>Fèvre</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. J.</given-names>
            <surname>Martins</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. M.</given-names>
            <surname>Muloi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Murray</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Mutinda</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Ogada</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G. P.</given-names>
            <surname>Omondi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Prasad</surname>
          </string-name>
          ,
          <string-name>
            <given-names>H.</given-names>
            <surname>Wild</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. M.</given-names>
            <surname>Zimmerman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. M.</given-names>
            <surname>Hassell</surname>
          </string-name>
          ,
          <article-title>Strengthening global health security by improving disease surveillance in remote rural areas of low-income and middle-income countries</article-title>
          ,
          <year>2022</year>
          . URL: https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(
          <issue>22</issue>
          )
          <fpage>00031</fpage>
          -
          <lpage>6</lpage>
          / fulltext. doi:
          <volume>10</volume>
          .1016/
          <fpage>S2214</fpage>
          -109X(
          <issue>22</issue>
          )
          <fpage>00031</fpage>
          -
          <lpage>6</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          <article-title>[8] Working together for the health of humans, animals, plants and the environment</article-title>
          .
          <source>One Health Joint Plan of Action</source>
          (
          <year>2022</year>
          -2026), Bulletin de l'
          <source>OIE</source>
          <year>2022</year>
          (
          <year>2022</year>
          )
          <fpage>18</fpage>
          -
          <lpage>19</lpage>
          . doi:
          <volume>10</volume>
          . 20506/bull.
          <year>2022</year>
          .
          <volume>2</volume>
          .3324.
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>World</given-names>
            <surname>Health</surname>
          </string-name>
          <string-name>
            <surname>Organisation</surname>
          </string-name>
          ,
          <article-title>Framework for a Public Health Emergency Operations Centre</article-title>
          , World Health Organisation,
          <year>2015</year>
          . URL: https://www.who.int/publications/i/item/ framework
          <article-title>-for-a-public-health-emergency-operations-centre.</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10] WHO,
          <article-title>Handbook for Public Health Emergency Operations Center Operations and Management</article-title>
          .,
          <year>2021</year>
          . URL: https://africacdc.org/download/ handbook
          <article-title>-for-public-health-emergency-operations-center-operations-and-management/.</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <given-names>Ethiopia</given-names>
            <surname>Public Health</surname>
          </string-name>
          <article-title>Institute (EPHI), National Public Health Emergency Operation Center Handbook</article-title>
          ,
          <source>Technical Report</source>
          ,
          <year>2022</year>
          . URL: https://ephi.gov.et/wp-content/uploads/ 2022/07/EPHI_cPHEM_EWISMD_PHEOC_Handbook_V1.pdf.
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <surname>UNAIDS</surname>
          </string-name>
          ,
          <string-name>
            <surname>Fast-Track</surname>
            <given-names>Targets</given-names>
          </string-name>
          ,
          <source>Technical Report</source>
          ,
          <year>2020</year>
          . URL: https://www.unaids.org/sites/ default/files/media_asset/201506_JC2743_
          <article-title>Understanding_FastTrack_en</article-title>
          .pdf.
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <surname>Pepfar</surname>
          </string-name>
          ,
          <string-name>
            <surname>Reimagining PEPFAR's Strategic</surname>
            <given-names>Direction</given-names>
          </string-name>
          ,
          <source>Technical Report</source>
          ,
          <year>2022</year>
          . URL: https: //www.state.gov/wp-content/uploads/2022/09/PEPFAR-Strategic-Direction_FINAL.pdf.
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <given-names>B.</given-names>
            <surname>Rice</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Boulle</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Baral</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Egger</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Mee</surname>
          </string-name>
          , E. Fearon, G. Reniers,
          <string-name>
            <given-names>J.</given-names>
            <surname>Todd</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Schwarcz</surname>
          </string-name>
          , S. Weir,
          <string-name>
            <given-names>G.</given-names>
            <surname>Rutherford</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Hargreaves</surname>
          </string-name>
          ,
          <article-title>Strengthening routine data systems to track the HIV epidemic and guide the response in Sub-Saharan Africa</article-title>
          ,
          <source>JMIR Public Health and Surveillance</source>
          <volume>4</volume>
          (
          <year>2018</year>
          ). doi:
          <volume>10</volume>
          .2196/publichealth.9344.
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <given-names>D.</given-names>
            <surname>Moodley</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Pillay</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Seebregts</surname>
          </string-name>
          ,
          <article-title>Establishing a health informatics research laboratory in South Africa</article-title>
          , in: Digital Re-imagination
          <source>Colloquium</source>
          <year>2018</year>
          :
          <article-title>Preparing South Africa for a Digital Future through e-Skills</article-title>
          ,
          <string-name>
            <surname>NEMISA</surname>
          </string-name>
          ,
          <year>2018</year>
          , pp.
          <fpage>16</fpage>
          -
          <lpage>24</lpage>
          . URL: https://www.cair.org.za/ sites/default/files/2020-02/HeAL-NEMISA-
          <year>2018</year>
          .pdf.
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <given-names>M. N. Kamel</given-names>
            <surname>Boulos</surname>
          </string-name>
          ,
          <string-name>
            <surname>P. Zhang,</surname>
          </string-name>
          <article-title>Digital twins: From personalised medicine to precision public health</article-title>
          ,
          <year>2021</year>
          . doi:
          <volume>10</volume>
          .3390/jpm11080745.
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <given-names>G.</given-names>
            <surname>Ahmadi-Assalemi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>H.</given-names>
            <surname>Al-Khateeb</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Maple</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Epiphaniou</surname>
          </string-name>
          ,
          <string-name>
            <given-names>Z. A.</given-names>
            <surname>Alhaboby</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Alkaabi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Alhaboby</surname>
          </string-name>
          ,
          <article-title>Digital twins for precision healthcare</article-title>
          ,
          <source>in: Advanced Sciences and Technologies for Security Applications</source>
          ,
          <year>2020</year>
          . doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>030</fpage>
          -35746-7{\_}
          <fpage>8</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <given-names>G.</given-names>
            <surname>Coorey</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G. A.</given-names>
            <surname>Figtree</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. F.</given-names>
            <surname>Fletcher</surname>
          </string-name>
          ,
          <string-name>
            <surname>J. Redfern,</surname>
          </string-name>
          <article-title>The health digital twin: advancing precision cardiovascular medicine</article-title>
          ,
          <year>2021</year>
          . doi:
          <volume>10</volume>
          .1038/s41569-021-00630-4.
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <given-names>A.</given-names>
            <surname>Fuller</surname>
          </string-name>
          ,
          <string-name>
            <given-names>Z.</given-names>
            <surname>Fan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Day</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Barlow</surname>
          </string-name>
          , Digital Twin: Enabling Technologies, Challenges and Open Research, IEEE Access 8
          <article-title>(</article-title>
          <year>2020</year>
          )
          <fpage>108952</fpage>
          -
          <lpage>108971</lpage>
          . doi:
          <volume>10</volume>
          .1109/ACCESS.
          <year>2020</year>
          .
          <volume>2998358</volume>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <given-names>S.</given-names>
            <surname>Abburu</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A. J.</given-names>
            <surname>Berre</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Jacoby</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Roman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Stojanovic</surname>
          </string-name>
          ,
          <string-name>
            <surname>N.</surname>
          </string-name>
          <article-title>Stojanovic, COGNITWIN - Hybrid and Cognitive Digital Twins for the Process Industry</article-title>
          , in: Proceedings - 2020
          <source>IEEE International Conference on Engineering, Technology and Innovation, ICE/ITMC</source>
          <year>2020</year>
          ,
          <year>2020</year>
          . doi:
          <volume>10</volume>
          .1109/ICE/ITMC49519.
          <year>2020</year>
          .
          <volume>9198403</volume>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          [21]
          <string-name>
            <given-names>X.</given-names>
            <surname>Zheng</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Lu</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Kiritsis</surname>
          </string-name>
          ,
          <article-title>The emergence of cognitive digital twin: vision, challenges and opportunities</article-title>
          ,
          <source>International Journal of Production Research</source>
          <volume>60</volume>
          (
          <year>2022</year>
          )
          <fpage>7610</fpage>
          -
          <lpage>7632</lpage>
          . doi:
          <volume>10</volume>
          .1080/00207543.
          <year>2021</year>
          .
          <volume>2014591</volume>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>